JP2019182590A - Sheet feeder and sheet processing apparatus, and image reading apparatus - Google Patents

Abstract

To provide a sheet processing apparatus and image processing apparatus capable of effectively preventing poor processing of a sheet.SOLUTION: A sheet processing apparatus comprises feeding means that feeds a sheet, a plurality of detection sensors that are juxtaposed orthogonally to a sheet-feed direction in a downstream in the sheet-feed direction of the feeding means, processing means that is provided downstream in the sheet-feed direction of the plurality of detection sensors and performs predetermined processing on the sheet, and control means that controls a start or termination of the predetermined processing the processing means performs on the sheet based on detection timing by the plurality of detection sensors. The plurality of detection sensors detect a sheet movement amount of the sheet moving toward the processing means.SELECTED DRAWING: Figure 2

Description

  The present invention provides, for example, a sheet feeding apparatus used in a document scanner, a facsimile, a printer, a copying machine, and the like, a sheet processing apparatus provided with the sheet feeding apparatus, and a sheet image including the sheet processing apparatus. The present invention relates to an image reading apparatus.

  2. Description of the Related Art Conventionally, there is known an image reading apparatus that reads an image based on a timing at which a leading edge of a document is detected while conveying the document (see Patent Document 1).

JP 2010-141737 A

  In a conventional image reading apparatus, for example, when a conveyance failure such as skew feeding in which a document is conveyed obliquely occurs, subsequent reading processing may be affected. Such a problem may occur not only in the above-described image reading process but also in other processes including, for example, printing as well as a processing failure, and regardless of the size of the document, There is a possibility that the same occurs in various media (sheets).

  The present invention provides a sheet feeding apparatus, a sheet processing apparatus, and an image reading apparatus that can effectively prevent sheet processing defects.

The present invention is a sheet feeding apparatus that feeds a sheet toward a processing unit that performs a predetermined process on the sheet, the feeding unit feeding the sheet, and the sheet feeding of the feeding unit A plurality of detection sensors provided in a direction orthogonal to the sheet feeding direction on the downstream side of the direction, and a control unit that controls the driving of the feeding unit based on detection results of the plurality of detection sensors; And the plurality of detection sensors are sensors for detecting a rotation state of a rotating body that rotates following the sheet being fed.
According to this aspect of the present invention, since the driving of the feeding unit is stopped based on the rotation state of the rotating body in the plurality of detection sensors, it is possible to effectively prevent the sheet processing failure performed thereafter.

In the present invention, a determination unit that determines a sheet feeding abnormality based on detection results of the plurality of detection sensors, and a designation unit that designates a next process after the determination unit determines the sheet feeding abnormality. And when the determination means determines that the sheet is abnormally fed, the control means stops driving the feeding means, and then executes the next process based on a designation operation from the designation means. This may be a feature.
According to this aspect of the present invention, the user can specify the next processing to be performed after the sheet feeding is stopped. For example, the handling of the sheet whose feeding is stopped can be accepted by a user operation. Can be improved.

In the present invention, the next process may be characterized in that the feeding means resumes the operation of feeding sheets toward the downstream side in the sheet feeding direction.
According to this aspect of the present invention, if the sheet that has stopped feeding stays in the apparatus, the next process cannot be performed, so the sheet needs to be taken out from the apparatus, but the sheet feeding operation is resumed. By allowing the operation to be accepted, it is possible to save the trouble of taking out the sheet from the apparatus.

In the present invention, the next processing may be characterized in that the feeding unit starts an operation of feeding the sheet backward toward the upstream side in the sheet feeding direction.
According to this aspect of the present invention, since the next process cannot be performed if the sheet that has stopped feeding remains in the apparatus, it is necessary to take out the sheet from the apparatus, but the sheet is returned to the mounting table side. By making it possible to accept an operation for starting the operation, it is possible to save the trouble of taking out the sheet from the apparatus and to reduce the trouble of replacing the sheet with respect to the mounting table.

In the present invention, the next processing is performed by the feeding unit performing an operation of feeding the sheet backward toward the upstream side in the sheet feeding direction, and then feeding the sheet toward the downstream side in the sheet feeding direction. It may be a series of switchback operations for feeding.
According to this aspect of the present invention, since the next process cannot be performed if the sheet that has stopped feeding remains in the apparatus, the sheet needs to be taken out from the apparatus, but the sheet is returned to the mounting table side. The operation to shift to the feeding operation can be received again, thereby eliminating the trouble of taking out the sheet from the apparatus, the trouble of resetting the sheet on the mounting table, and the operation for resuming the sheet feeding. Can also be reduced.

In the present invention, the next process may be a process based on a preset initial setting.
According to such an aspect of the present invention, it is possible to smoothly shift to the next process by setting the next process after stopping the sheet feeding in advance.

In the present invention, it is provided with a notification means for notifying the external device that the driving of the feeding means has been stopped, and the notification means sends the notification to the external device when the next process is not set as the initial setting. Notification or notification to the display means included in the device itself may be executed.
According to such an aspect of the present invention, notification to an external device such as a computer (error notification or the like) is performed when the initial setting is not set, so that notification to the external device can be reduced.

As another aspect of the present invention, a feeding unit that feeds a sheet, and a plurality of detection sensors provided in a direction orthogonal to the sheet feeding direction on the downstream side of the sheet feeding direction of the feeding unit, A processing unit that is provided downstream of the plurality of detection sensors in the sheet feeding direction, and that performs a predetermined process on the sheet; and driving of the feeding unit based on detection results of the plurality of detection sensors Control means for stopping and controlling, wherein the plurality of detection sensors are sensors that detect a rotation state of a rotating body that rotates following the sheet being fed, and the processing means is configured to detect the plurality of detection means. The predetermined processing is performed on the sheet based on the rotation state of the rotating body detected by a sensor.
According to this aspect of the present invention, it is possible to determine whether to perform predetermined processing or to stop driving of the feeding unit based on detection results of a plurality of detection sensors, thereby preventing a decrease in sheet processing productivity. Predetermined processing can be performed efficiently.

In the present invention described above, the image forming apparatus further includes a conveying unit that conveys the sheet fed by the feeding unit toward the processing unit, and the conveying unit is provided in the axial direction of a rotationally driven drive shaft. A plurality of first and second transport rollers that are rotationally driven together with a drive shaft, a first driven roller that is driven to rotate by the first transport roller, and a second driven roller that is driven to rotate by the second transport roller, The rotating body included in the detection sensor may be provided to be rotatable independently of each roller on the rotation shafts of the first and second driven rollers or the drive shaft.
According to this aspect of the present invention, by providing the rotating body on the roller shaft of the drive system, the movement of the sheet can be detected with high accuracy based on the rotating state of the rotating body.

In the present invention, the plurality of detection sensors detect arrival and passage of a sheet, and a sheet movement amount obtained based on outputs of the plurality of detection sensors and detection by the plurality of detection sensors. Control means for controlling driving of the processing means based on the timing may be provided.
According to this aspect of the present invention, the skew state of the sheet can be grasped based on the detection timings of the plurality of detection sensors, and the processing of the sheet can be accurately performed by obtaining the subsequent seed movement amount.

Further, in the present invention, the control unit is configured to detect the leading edge of the sheet at a position upstream of the processing position by the processing unit in the sheet feeding direction based on the detection timings by the plurality of detection sensors. The start of the predetermined process by the processing means may be controlled.
According to this aspect of the present invention, for example, when the skew of the sheet occurs, the start of the predetermined process can be controlled depending on the degree thereof, so that a processing failure can be effectively prevented.

Further, in the present invention, the control unit has the trailing end of the sheet reach a position downstream of the processing position by the processing unit in the sheet feeding direction based on detection timings by the plurality of detection sensors. The completion of the predetermined processing by the processing means may be controlled at timing.
According to this aspect of the present invention, for example, when the skew of the sheet occurs, the start of the predetermined process can be controlled depending on the degree thereof, so that a processing failure can be effectively prevented.

In the present invention, the control unit may control not to perform the predetermined process by the processing unit when detection results of the plurality of detection sensors exceed a predetermined threshold.
According to this aspect of the present invention, when it is determined that it is difficult to continue the predetermined process based on the detection results of the plurality of detection sensors, for example, the sheet feeding, the start of the process, etc. are stopped. It is possible to prevent re-execution of predetermined processing. The predetermined threshold here is a threshold for determining whether or not to perform predetermined processing, and may be a threshold different from the threshold for determining abnormal sheet feeding or the same threshold.

  Note that the present invention provides an image reading apparatus such as a scanner, an image forming apparatus such as a printer, and a multi-function including these in combination. The image reading apparatus is characterized by reading an image of a sheet fed by the above-described sheet feeding apparatus. Can be widely applied to copiers and multifunction machines.

  According to the present invention, it is possible to realize a sheet feeding apparatus and an image reading apparatus that can effectively prevent sheet processing defects.

1 is a schematic diagram of a document conveying device according to an embodiment of the present invention. FIG. 3 is a schematic diagram of an encoder viewed from the paper feed roller side. The output waveform figure of an encoder. Examples of images before and after distortion correction. Examples of images before and after distortion correction. Number of pixels in the f-th pulse before and after distortion correction. FIG. 6 is a flowchart showing scan processing in the image reading apparatus. The flowchart figure which shows a scan end process. The flowchart figure which shows a double feed post-process. The flowchart figure which shows AM post-process. The flowchart figure which shows the double feed recovery waiting process. The flowchart figure which shows a JAM recovery waiting process. Schematic of an image reading apparatus according to another embodiment. FIG. 14 is a block diagram of a control unit of the image reading apparatus in FIG. 13.

  Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings.

  As shown in FIG. 1, a document scanner 1 according to the present embodiment is an original image reading apparatus that is an example of a sheet processing apparatus in which a sheet feeding apparatus that performs sheet feeding is mounted. Is a lower guide unit 2a that constitutes the conveyance path wall on the lower side in the vertical direction (apparatus installation surface side), and an upper guide unit that constitutes the conveyance path wall on the upper side in the vertical direction. The conveyance path 10 for the document D is formed in a space between the upper and lower guide units 2a and 2b. Note that the direction in which the transport path 10 extends is the feeding direction of the document D (sheet feeding direction).

  Here, the pickup roller 8, the paper feed roller 9, and the separation roller 3 are an example of a feeding unit that is driven by a paper feed motor (not shown). The pickup roller 8 and the paper feed roller 9 feed the uppermost document D of the document stack placed on the paper feed tray 4 to the downstream side. The separation roller 3 is pressed against the paper feed roller 9 and rotates in the opposite direction to the paper feed roller 9 to separate the originals D from the original bundle one by one. The separation roller 3 may be a separation pad made of a friction member.

  The lower guide unit 2a includes a separation roller 3, a paper feed tray 4, a lower reading sensor 5a, an upstream side conveyance roller 6a, and a downstream side conveyance roller 7a. The upper guide unit 2 b includes a pickup roller 8, a paper feed roller 9, an upper reading sensor 5 b, upstream conveyance roller pairs 6 a and 6 b, a downstream conveyance roller 7 b, and an encoder 11. The lower guide unit 2a is connected so that the paper feed tray 4 can be accommodated, and a portion to which the front end of the original or the original bundle is placed is connected to the portion where the paper feed tray 4 is connected. The placement portion of the lower guide unit 2a is provided with an optical paper feed sensor (document placement sensor) S1 that detects whether or not a document is placed.

  Further, the document D separated one by one by the paper feed roller 9 and the separation roller 3 is supplied to the conveyance path 10, but the paper feed roller 9 and the separation roller 3 and the upstream side conveyance roller pairs 6a and 6b are connected to each other. In between, there are provided a double feed detection sensor S2, which will be described later, and a pre-registration sensor S3 on the downstream side of the double feed detection sensor S2. The pre-registration sensor S3 detects the arrival and passage of the document D, that is, the leading edge and the trailing edge of the document D. An ultrasonic double feed detection sensor S2 is provided upstream of the pre-registration sensor S2 in the document conveyance direction. When the document is fed to the conveyance path 10 in a double feed state without being fed between the paper feed roller 9 and the separation roller 3, the double feed detection sensor S2 performs double feed detection.

  The lower reading sensor 5a and the upper reading sensor 5b, which are examples of processing means, are arranged to face each other with the conveyance path 10 in between. The pair of upstream conveyance rollers 6a and 6b and the downstream conveyance rollers 7a and 7b are in contact with each other on the conveyance path 10, and the upstream conveyance roller 6a and the downstream conveyance roller 7a on the lower guide unit 2a side are not illustrated. The upstream side conveyance roller 6b and the downstream side conveyance roller 7b on the upper guide unit 2b side are driven rollers.

  As shown in FIG. 2, each roller on the upstream side of the conveying means in the conveying path 10 is a set each in a direction orthogonal to the feeding direction of the document D (that is, the axial direction of each roller). It is provided at intervals. In other words, the document D fed by the paper feed roller 9 includes left and right upstream transport rollers (first transport roller, second transport roller) 6a, and upstream transport rollers (first driven roller, second transport roller) that follow the upstream transport rollers 6a. When sandwiched between the driven rollers 6b, it is conveyed toward the downstream side.

  Further, the lower reading sensor 5a and the upper reading sensor 5b are sandwiched between the upstream side and the downstream side by the rotation of the upstream side conveyance rollers 6a and 6b and the downstream side conveyance rollers 7a and 7b and are stable (for example, faster than the feeding speed). The images of the lower surface and the upper surface of the document D conveyed at high speed and at a constant speed are optically read.

  Here, either one of the lower reading sensor 5a and the upper reading sensor 5b serving as such an image reading means (processing means for performing a predetermined process) may be used. The arrival and / or passage of the document D is detected on the side, and the image reading start and end timings are controlled based on the detection timing.

  For example, in the present embodiment, in the transport unit described above, an encoder 11 using a plurality of detection sensors (an encoder 11 that is a rotating body that is driven and rotated in contact with the document D moving on the transport path). Sensor for detecting the amount of rotation or angle of rotation), and the image reading start and end timings are controlled based on the detection timings of the plurality of detection sensors.

  Here, for example, in the present embodiment, one detection sensor includes an encoder 11 and a detection unit (photo interrupter) 131 that detects the rotation of the encoder 11. The encoder 11 is arranged on the rotation shaft of the upstream conveying roller 6b, starts rotating from the timing when the leading edge and the trailing edge of the conveyed document D come into contact with each other, and continues to rotate as the document D moves. To do.

  By detecting such rotation of the encoder 11 optically by the detection unit 131, for example, the timing at which the leading edge of the document D arrives, the movement amount and speed of the document D, and the timing at which the trailing edge of the document D is removed. It can detect from the output signal of each sensor.

  In other words, in the present embodiment, the left and right detection sensors (first rotation detection sensor and second rotation detection sensor) can detect the arrival and passage of the document D and the movement between them. For this reason, when the document D enters the detection area in a skewed state, either the left or right detection sensor detects first, and the other detection sensor detects after that. In the case of the document D without skew, there is no difference between the detection timings of the left and right detection sensors, and the start / end of image reading is controlled based on the detection timing.

  Therefore, when skew occurs, a difference in detection timing between the left and right detection sensors occurs. In this case, for example, control is performed to start reading an image based on the timing at which the document D is detected first. You may make it do. As a result, the start of image reading can be executed in the shortest time based on the detection timings of the left and right detection sensors, so that reading defects such as image chipping can be effectively reduced.

  In any case, the control unit that controls the lower reading sensor 5a and the upper reading sensor 5b generates control signals for reading start and end based on the detection of the leading edge and the trailing edge of the document, and detects the detected conveyance speed (movement). Image acquisition and conveyance control of the lower reading sensor 5a and the upper reading sensor 5b are performed at a timing based on (speed).

  Note that the control unit may perform control so that image reading processing is not performed when the detection timing difference exceeds a predetermined threshold. In this case, the paper may be discharged while being skewed. However, if the document is damaged if the document feeding is continued while the document is skewed, the feeding or the conveyance should be stopped. May be.

  Here, the configuration of the encoder 11 will be described with reference to FIG. 2 which is a schematic view seen from the paper feed roller 9 side. The encoder 11 is pivotally supported at both ends of a roller shaft 12 that rotatably supports the upstream-side transport roller 6b.

  Although FIG. 2 illustrates an example of the structure provided on both outer sides of the left and right upstream transport rollers 6b, it can also be provided inside the left and right upstream transport rollers 6b. Further, the outer diameter of the encoder 11 is formed larger than the outer diameter of the upstream-side transport roller 6b. Thus, the document D can be slidably contacted and rotated.

  The encoder 11 is positioned in the thrust direction (not shown) so as not to come into contact with the transport roller 6b and is rotatably supported. The encoder 11 is formed of a high friction material such as rubber, and has a paper detection roller 11a that rotates around the conveyed document, and rotates in conjunction with the paper detection roller 11a.

  The upstream-side transport roller 6b rotates with the upstream-side transport roller 6a regardless of whether or not there is a document, but the encoder 11 rotates with the transported document and stops when there is no transported document. That is, since the encoder 11 is interlocked with the movement of the transported document, the state of movement of the transported document can be detected by detecting the rotation state of the encoder 11.

  The detection unit 131 that detects the rotation of the encoder 11 and the substrate 132 of the detection unit are fixed to the upper guide unit 2b. The detection unit 131 detects the time when the encoder 11 changes from the stopped state to the rotating state as the document leading edge, and detects the time when the encoder 11 changes from the rotating state to the stopped state as the document trailing edge.

  For example, when the document is not skewed, the rotation of the left and right encoders 11 and the stop thereof are substantially synchronized, and during that time, it is estimated that the document is being conveyed in the conveyance direction. The amount can be estimated as the length in the document transport direction. The document length referred to here is the amount of movement of the document per unit time (sheet movement amount) obtained from the rotation amount of the encoder 11.

  Also, since each encoder 11 follows the document independently, when a skewed document enters, after one encoder 11 starts rotating, the other encoder 11 starts rotating and skewed. When the document passes through the detection area of each encoder 11, the rotation of one encoder 11 ends first, and then the rotation of the other encoder 11 ends.

  In the detection of the skewed document, the timing at which the stopped encoder 11 first changes to the rotating state is detected as the leading edge of the document, and the timing at which the rotating encoder 11 changes to the stopped state later is the trailing edge of the document. , It is easy to shift to reading start and end control. It should be noted that the length of the document when skewed is estimated to be the length in the document transport direction based on the amount of rotation from when the encoder 11 first rotates to when the other encoder 11 stops last. It may be. The document length here is the amount of movement of the document per unit time determined from the amount of rotation of the encoder 11.

  The document reading timing is determined by calculating the time for the document leading edge / rear edge to reach the reading line from the document leading edge / rear edge detection information of the encoder 11 and the rotation speed at the document leading edge / rear edge.

  For example, in the document conveying apparatus of the present embodiment, since the actual rotation speed of the encoder 11 is used, the reading start / end positions are determined more accurately, so that it is possible to prevent missing images and set the paper interval to be unnecessarily long. The number of processed sheets per hour can be increased.

  A post-registration sensor is provided between the lower reading sensor 5a and the upper reading sensor 5b and the upstream conveying roller pair 6a and 6b to detect arrival and passage of the document D, and subsequent reading control, jamming, etc. It may be used for detecting anomalies. In that case, the above-described plurality of detection sensors (sensors that detect the rotation state of the left and right encoders 11) do not perform image reading control based on the arrival and passage timing of the document, but based on the left and right rotation difference. What is necessary is just to detect abnormal feeding of the document such as skew and rotation.

<Image reading control>
Here, an example of image reading control will be described.
For example, regarding the start of image reading, it may be controlled to start reading an image based on the detection timing of the encoder 11 that has been rotated first, or the image reading may be performed based on the detection timing of the encoder 11 that has been rotated later. You may control to start. The former can start reading an image immediately after detection by the encoder 11, and therefore can effectively prevent reading defects such as a chip in the image. In the latter case, image reading of the document can be started at a predetermined timing in consideration of the degree of skew of the document, and extra background reading can be reduced.

  Alternatively, after the encoder 11 that has been rotated first is detected, image reading may be started after a predetermined interval. In other words, the control unit (control means) that performs image reading control has the leading edge of the document from the image reading positions (processing positions) of the lower reading sensor 5a and the upper reading sensor 5b based on the detection timing when the encoder 11 is rotated. Also, the start of image reading processing by the lower reading sensor 5a and the upper reading sensor 5b is controlled at the timing when the position reaches the upstream position in the document feeding direction. As a result, it is possible to prevent reading defects such as missing images while reducing unnecessary background reading.

  Note that another document detection sensor is provided upstream of the encoder 11 in the document conveyance direction, and reading is started based on the detection result of the document detection sensor (starts immediately after detection by the document detection sensor, or a predetermined time after detection). It is also possible to control starting). In this case, the detection result of the encoder 11 is used for image distortion correction, although details will be described later.

Next, the end of image reading will be described.
For example, the image reading is performed with high accuracy even when the document is skewed by controlling the image reading to be terminated based on the detection timing of the encoder that has stopped rotating later among the left and right encoders 11. be able to.

  Specifically, the control unit (control unit) that performs image reading control is configured such that the trailing edge of the document is positioned at each image reading position (lower reading sensor 5a and upper reading sensor 5b) based on the detection timing when the encoder 11 is rotated. The start of image reading processing by the lower reading sensor 5a and the upper reading sensor 5b is controlled at a timing when the position reaches a position downstream of the processing position) in the document feeding direction. Thereby, reading defects such as image chipping can be prevented.

  Further, another document detection sensor may be provided on the upstream side of the image reading sensor in the conveyance direction, and the image reading may be terminated after a predetermined time has elapsed since the detection by the document detection sensor.

  Note that another document detection sensor (image reading sensor passage sensor) is provided downstream of the image reading sensor in the conveyance direction, and based on the detection result of the document detection sensor, reading of an image by the image reading sensor is terminated. You may control. In this case, it is possible to prevent reading defects such as missing images more reliably by providing a gap between the image reading sensor and the document detection sensor on the downstream side.

(Other image reading control)
If there is a difference in detection timing among a plurality of detection sensors, it means that the document is skewed. Therefore, if the difference in detection timing is within a predetermined threshold, the image reading is continued. However, if it is outside the predetermined threshold, the image reading and feeding / conveyance may be stopped in order to prevent document damage.

  Further, in the above description, the arrival and passage of the document are detected by a plurality of detection sensors using the encoder, but such arrival and passage of the document are not detected, and based on the rotation amount of the encoder, Only the amount of movement of the document is detected, and based on the detection result, processing on the document (here, image reading is illustrated, but the type of processing may be other processing such as printing). Good.

  In addition, the control unit that controls reading of the image or the like is based on the detection timing of the plurality of detection sensors (the detection unit 131 that detects that the left and right encoders 11 start or stop rotating), or a detection timing difference. An instruction signal for starting reading of the image reading sensors (lower reading sensor 5a and upper reading sensor 5b) and an instruction signal for ending reading of the image reading sensor are issued.

  That is, the control unit controls the start of image reading at the timing when the leading edge of the document reaches a position upstream in the document feeding direction from the reading position of the image reading sensor (the lower reading sensor 5a and the upper reading sensor 5b). To do. Further, the control unit controls the completion of image reading at a timing when the trailing edge of the document reaches a position downstream of the reading position of the image reading sensor in the document feeding direction. Thus, the start and end of reading by the image reading sensor that has received the instruction signal from the control unit is controlled.

  Further, the reading timing of the document leading edge is not limited to the method of determining from the rotation speed of the encoder 11, for example, and may be a method of starting reading when the encoder generates a predetermined number of pulses after detecting the document leading edge.

  Further, when the time required for the encoder 11 to generate a predetermined number of pulses (hereinafter referred to as rotation time) differs between the left and right encoders 11, image distortion correction is performed. Here, the image distortion correction may be executed by, for example, an image correction unit provided in the image reading apparatus, or an image correction unit provided in an information processing apparatus such as a computer connected to the image reading apparatus. Alternatively, the image correction unit provided in the image reading apparatus and the image correction unit provided in the information processing apparatus may be executed in cooperation.

When the rotation time for each pulse is acquired after the image reading is started and the rotation time of the f-th pulse is t _Lf and t _Rf by the left and right encoders 11, the f-th pulse is obtained when t _Lf ≠ t _Rf. Will be distorted.

FIG. 3 shows an output waveform of the encoder 11 when t _Lf > t _Rf . When this waveform is generated, the upper reading sensor 5b acquires a distorted image as shown in the left figure of FIG. The left diagram in FIG. 4 can divide the image into pulses as shown in FIG. 5 based on the output information of the encoder 11.

  In the distortion correction, as shown in FIG. 6, the image is expanded or contracted by increasing or decreasing the number of pixels of the f-th pulse.

Here, the designed number of pixels in one pulse of the encoder is L _s , and the number of pixels of the f-th pulse of the left and right encoders is L ₀ , L _a (rotation time t _Lf , t _Rf of the f-th pulse of the encoder ₎ The document conveyance distance can be obtained from the outer diameter of the paper detection roller 11a, and the number of pixels can be obtained from the conveyance distance.) When the distance between the left and right paper detection rollers 11a is a, any line k in the sub-scanning direction the pixel number L _k in the f-th pulse at, determined by the equation _{L k = (L a -L 0} ) / a * k + L 0, to L _s by stretching a L _k.

  The above method is a method of uniformly expanding and contracting within one line, but is not limited thereto, and for example, a method of correcting image distortion by performing thinning may be adopted.

  As described above, when the left and right conveyance speeds of the document are different from the designed conveyance speed, when the result scan image is distorted, the distortion of the image can be corrected by the information of the encoder 11. For example, an embossed plastic card or the like has a non-uniform thickness and a partially thick portion. Therefore, when such a document is transported, the balance between the contact pressures on the left and right of the transport rollers is likely to be lost, so the document may be rotated and transported, and an image read as it is may be a bent image. .

  According to the image reading apparatus of the present embodiment, the left and right encoders 11 are driven with respect to such a rotating document, so that a rotational difference occurs between the left and right encoders 11. For this reason, based on the rotation difference between the left and right encoders 11, a distorted portion of the bent image can be corrected and a scan image serving as output data can be generated. The rotation difference here is a difference in rotation amount between the left and right encoders 11, that is, a difference in movement amount of the document.

  When the document does not rotate, there is no difference in the amount of movement of the document obtained from the left and right encoders 11, but when the document rotates, the amount of movement of the document obtained from one encoder 11 and the document obtained from the other encoder 11 There will be a difference in the amount of movement. Therefore, in this embodiment, a desired image can be output by correcting the distortion of the bent image based on the rotation difference of the encoder 11.

  In the above embodiment, the encoder 11 is arranged on the roller shaft 12 of the upstream side conveyance roller 6b. However, the arrangement is not limited to this, and the encoder 11 is arranged anywhere between the upstream side conveyance roller 6b and the lower reading sensor 5a and the upper reading sensor 5b. May be. For example, a plurality of rotating bodies that follow the document in the conveyance path may be arranged in parallel in a direction orthogonal to the conveyance direction.

  Further, as in the present embodiment, when there is a speed difference between the feeding speed and the feeding speed in the feeding and feeding of the document (the feeding speed is set to be higher than the feeding speed), the image reading start control is performed. In this case, it is preferable to install a plurality of rotating bodies so as to follow the original after the original is transferred from feeding to conveyance, that is, when the original is conveyed at a constant speed. Or you may provide in the axis | shaft of the upstream conveyance roller 6a side, and you may provide in the axis | shaft of both the upstream conveyance rollers 6a and 6b. As a result, when there is slippage of a document in one encoder, more accurate reading control can be performed by using the output of the other encoder.

  In the sense of monitoring the movement of the document during conveyance, an encoder 11 is provided on each roller shaft to detect the arrival and passage of the document in the conveyance direction and the amount of movement at the position where the encoder 11 is disposed at a plurality of locations. In addition to being able to set the start timing of image reading with high accuracy, it can also be used to detect conveyance abnormalities.

  Further, if the encoder 11 is arranged on at least one of the rotation shafts of the separation roller 3 and the paper feed roller 9 in the above-described embodiment to detect the movement amount of the document in the separation feeding, When the originals are fed one by one at the nip portion between the separation roller 3 and the paper feed roller 9, it is possible to detect early separation failures such as skewing of the originals. The position where the encoder 11 is provided does not have to be provided on the rotating shafts of the separation roller 3 and the paper feed roller 9, and may be provided, for example, in the vicinity of the front and rear of these rollers.

  Further, by arranging the encoder 11 on each shaft of the separation roller 3 and the paper feed roller 9, for example, the rotation of the encoder 11 on the separation roller 3 side is the rotation of the encoder 11 on the paper feed roller 9 side. Can be used for detecting a feeding abnormality such as a phenomenon of bringing in a plurality of documents and double feeding.

  On the other hand, if the rotation of the encoder 11 on the separation roller 3 side is relatively small compared to the rotation of the encoder 11 on the paper feed roller 9 side, it is determined that the feeding state is normal when the predetermined condition is satisfied. Can do.

  In the above-described embodiment, the mode in which the subsequent image reading is continued when the document D serving as the transport medium is slightly skewed or rotated has been described in detail. A case where the feeding of the document D is temporarily stopped when the threshold value is equal to or greater than the threshold value will be described.

  Here, if the skew of the document D is greater than or equal to a predetermined threshold value, that is, if the document D is damaged due to skew feeding or if subsequent image reading becomes difficult if the feeding and conveyance are continued, the document immediately It is preferable to temporarily stop the feeding of D. For example, when a difference occurs between the rotation states of the left and right encoders 11 and the difference exceeds a predetermined threshold, the feeding and feeding of the document D are temporarily stopped as a jam (JAM) process. Thereby, the document D can be protected.

  When the image reading on the document D is to be performed again after the document D is temporarily stopped, the apparatus main body is opened (the conveyance path is opened), that is, the upper part of the lower guide unit 2a. If the guide unit 2b is lifted to open the conveyance path in which the document D stays and the document D is taken out from the apparatus, it may take time and effort for the user.

  For example, when a plastic card or the like is skewed or rotated to temporarily stop feeding and conveyance, it is convenient if the user can take out the card using the driving system of the own apparatus without opening the conveyance path. For this reason, it is preferable that the next processing after the document D is temporarily stopped can be designated (designated operation) by a simple user operation.

  Specifically, a user operation is received on an operation panel (an example of a designation unit) of the image reading apparatus, and a control unit (control unit) included in the image reading apparatus is configured to copy the document D based on the detection results of a plurality of detection sensors. If it is determined that the feeding abnormality has occurred, the control unit controls the feeding of the document D to be temporarily stopped, and the control unit causes the control unit to execute the next process based on the operation of the operation panel. Good.

  Here, as a next process after the feeding of the document D is temporarily stopped, for example, the pickup roller 8, the sheet feeding roller 9 and the separation roller 8, and the upstream conveyance roller pairs 6 a and 6 b are driven to rotate forward, that is, the document D is scanned. A control unit included in the image reading apparatus may control the driving of the driving motor so that the feeding is performed again in the feeding direction.

  Further, the image reading apparatus has a control for driving the pickup roller 8, the paper feeding roller 9, the separation roller 8, and the upstream conveying roller pairs 6a and 6b in the reverse direction, that is, returning the original D in the direction opposite to the feeding direction. The unit may control the drive of the drive motor.

  Further, a series of switchback driving for switching to normal rotation driving may be performed after the original D is driven to reverse rotation to a predetermined position.

  In any case, since the next process cannot be performed immediately after the stopped document D stays in the apparatus, it takes time to take out the document D from the apparatus. By making it possible to accept a specified operation by a user operation for any one of resumption, reverse rotation operation, and switchback operation, it is possible to save the trouble of taking out a sheet from the apparatus.

  If the switchback or reverse operation is performed, it is possible to reduce the user's trouble of resetting the document D on the mounting table 4, and if the switchback operation is performed, the operation for re-feeding can be omitted. Can do.

  The next process after the document D is temporarily stopped is a process based on a preset initial setting in an operation panel of the image reading apparatus or an external apparatus such as a computer to which the image reading apparatus is connected. Can do. In that case, for example, by assigning the next process to each operation button on the operation panel of the image reading apparatus, the user can designate the next process of the temporary stop of feeding of the document D by one or more buttons. It becomes possible to do. As described above, by setting the next process after stopping the feeding of the document D in advance, the transition to the next process can be performed smoothly.

  Hereinafter, an example of scan processing in the image reading apparatus of the present embodiment will be described in detail with reference to FIGS. As another example of the next process described above, a JAM post-process will be described in detail as a process after detecting a feeding abnormality based on the detection results of the plurality of detection sensors (results of the rotation state of the encoder 11). .

  FIG. 7 is a flowchart showing a scanning process in the image reading apparatus. In FIG. 7, the image reading apparatus first determines whether or not a start button (not shown) of the self apparatus has been pressed in a state where an external apparatus such as a computer is connected (step S600).

  If the result of this determination is that the start button has been pressed (YES in step S600), the paper feed sensor S1 confirms that the document D exists (YES in step S602), and then the main motor is driven to drive the document D. Is started (step S603). The documents D placed on the placing table 4 are separated one by one by the paper feed roller 9 and the separation roller 3 and fed into the apparatus.

  Here, the separation feeding in which the document D is separated and fed one by one from the document bundle is described as an example. However, the image reading apparatus performs separation feeding and non-separation without separation feeding. When the function of switching between feeding is implemented, there is a case where the start of feeding the document D is instructed in the switching state to non-separating feeding.

  On the other hand, when the start button is not pressed (NO in step S600) and the stop button (not shown) of the own apparatus is pressed (YES in step S601), the process proceeds to step S610, and the scan shown in FIG. Perform termination processing.

  Next, the leading edge of the document D fed into the apparatus passes through the pre-registration sensor S3 (YES in step S604), and after a predetermined time, the lower reading sensor 5a and the upper reading sensor 5b are controlled to control the document D. Image reading is started (step S605).

  On the other hand, when the leading edge of the document D does not pass the pre-registration sensor S3 (NO in step S604), it is determined whether or not the double feed of the document D is detected by the double feed detection sensor S2 (step S611). If double feed is detected (YES in step S611), the flow advances to step S613 to execute post-double feed processing in FIG. 9 described later.

  On the other hand, when double feed is not detected (NO in step S611), it is determined whether or not JAM is detected (step S612). When JAM is detected (YES in step S612), the document D is fed and conveyed. The process is temporarily stopped, the process proceeds to step S614, and the JAM post-process shown in FIG. On the other hand, when JAM is not detected (NO in step S612), the process returns to step S604.

  After the image reading in step S605 is started, the trailing edge of the document D passes through the pre-registration sensor S3 (YES in step S606), and the document is controlled by controlling the lower reading sensor unit 5a and the upper reading sensor 5b after a certain period of time. D image reading is terminated (step S607). The read image of the document D is sent to an external device such as a computer as image data.

  If it is determined in step S606 that the trailing edge of the document D has not passed the pre-registration sensor S3 (NO in step S606), it is determined whether or not double feed is detected by the double feed detection sensor S3 (step S606). S615) When a double feed is detected (YES in step S615), the process proceeds to step S617 to execute the post-double feed process of FIG. 9 to be described later.

  On the other hand, if double feed is not detected (NO in step S615), it is determined whether JAM is detected (step S616). If JAM is detected (YES in step S616), the process proceeds to step S618, which will be described later. The JAM post-processing shown in FIG. 10 is executed. On the other hand, when JAM is not detected (NO in step S616), the process returns to step S606.

  As a result of the determination in step S608, if the trailing edge of the document D does not pass through the discharge sensor S4 and the discharge sensor S4 does not detect discharge of the document D (NO in step S608), whether JAM is detected or not Is determined (step S619). If JAM is detected as a result of this determination (YES in step S619), the feeding and conveyance of the document D are temporarily stopped, and the process proceeds to step S620 to perform JAM post-processing in FIG. (NO in step S619), the process returns to step S608.

  Next, when the trailing edge of the document D passes the sheet discharge sensor S4 (YES in step S608), the document D is discharged and the main motor is stopped (step S609), and the process returns to step S602 and the process is repeated. When all of the plurality of documents D placed on the mounting table 4 have been read and the document D is no longer detected by the paper feed sensor S1 (NO in step S602), the process proceeds to step S610 to execute a scan end process. .

<Scan end processing>
FIG. 8 is a flowchart showing the scan end process in step S610 of FIG.

  In FIG. 8, after the main motor is stopped as a scan end process (step S802), it is determined whether or not the image reading has ended without error (step S803). When the scan ends without error (YES in step S803). ) Notifying the external device that there is no next document (step S804), and the process is terminated.

  The external device that has received that there is no next document displays a continuation dialog on the display by the scanner driver, and prompts the operator to determine whether or not to continue image reading. On the other hand, as a result of the determination in step S803, if the process ends with an error (or ends due to an error) (NO in step S803), the reason for the end due to the error is notified to the external device (step S805), and this process is performed. finish.

<Post-feed processing>
Next, the post-multifeed processing in steps S613 and S617 in FIG. 7 will be described with reference to FIG. FIG. 9 is a flowchart showing the post-multifeed processing in steps S613 and S617 of FIG.

  In FIG. 9, when double feed of the document D is detected by the double feed detection sensor S2 during document conveyance or image reading, a screen indicating that double feed has been detected is displayed on the LCD on the operation panel (step S902). Then, it is determined whether or not to notify a double feed detection error to an external device such as a computer based on a set value set in advance by the operator from the operation panel (step S903). If a double feed detection error is notified as a result of this determination (YES in step S903), the double feed detection error is held in the flash memory 207 as the reason for termination due to the error (step S904), and the scan end process of FIG. 8 is executed. (Step S601).

  In this scan end process, in step S805, the external device is notified that a double feed detection error has been detected as the reason for the end due to the error. The external device that has received the double feed detection error displays an error dialog on the display by the scanner driver. On the other hand, as a result of the determination in step S903, when a double feed detection error is not notified (NO in step S903), the process proceeds to step S905, and a double feed recovery waiting process in FIG.

<JAM post-processing>
Next, post-JAM processing in steps S614, S618, and S620 of FIG. 7 will be described with reference to FIG. FIG. 10 is a flowchart showing the JAM post-processing in steps S614, S618, and S620 of FIG.

  In FIG. 10, during document conveyance or image reading, the paper feed JAM (step of FIG. 7) is performed by the fluctuation JAM based on the rotation difference of the encoder 11, the paper feed sensor S1, the pre-registration sensor S3, the paper discharge sensor S4, and the timer. When JAM is detected such as S612), stagnant JAM (step S616 in FIG. 7), paper discharge JAM (step S619 in FIG. 7), a screen indicating that JAM has been detected is displayed on the LCD on the operation panel (step S612). S1002), it is determined whether or not to notify a JAM detection error based on a setting value set in advance from the operation panel by the operator (step S1003).

  Here, the JAM detection by the timer means that when each sensor is turned on / off, the counter value measured by the timer is acquired, and the JAM detection is performed by comparison with the counter value taken to pass between the sensors. Is what you do.

  If it is determined in step S1003 that a JAM detection error is to be notified (YES in step S1003), the JAM detection error is held in the flash memory as the reason for termination due to the error (step S1004), and the scan end process in FIG. 8 is executed. (Step S610).

  In this scan end processing, in step S805, the external device is notified that a JAM detection error has been detected as the reason for the end due to the error. The external device that has received the JAM detection error displays an error dialog on the display by the scanner driver.

  On the other hand, as a result of the determination in step S1003, when a JAM detection error is not notified (NO in step S1003), the process proceeds to step S1005, and a JAM recovery waiting process shown in FIG.

<Multifeed recovery waiting process>
FIG. 11 is a flowchart showing the double feed recovery waiting process in step S905 of FIG. In FIG. 11, after the document D that has caused double feeding in the image reading apparatus 200 is removed by the operator (YES in step S102), a confirmation message as to whether or not to continue scanning is displayed on the LCD on the operation panel. (Step S103).

  Next, it is determined whether or not the start button has been pressed (step S104). If the start button has been pressed (YES in step S104), the process returns to step S602 in FIG. The setting value stored in the flash memory is read, and scanning is resumed based on the setting value. On the other hand, when the start button is not pressed (NO in step S104) and the stop button is pressed (YES in step S105), a scan end process is executed.

  In this way, the operator removes a document that has been detected as a double feed such as an envelope by removing the original D that has caused double feed in the image reading apparatus, placing it again on the mounting table 4 and pressing the start button. Even if the document is intentionally sent, if the start button is pressed as it is, reading of the subsequent document can be continued.

  Further, it is possible to read a document image without resetting when an operator detects an error. In addition to this, even when a sticky note or the like is pasted on the document D, double feed detection is performed, but there is a case where it is desired to continue feeding and feeding as it is. By the operation), it is possible to continue image reading with only a button operation without opening the conveyance path of the image reading apparatus. The conveyance may be stopped immediately after the double feed is detected, but the conveyance may be stopped while being held at the discharge roller. In this case, if the discharge process is performed by the button operation described above, Good.

<JAM recovery waiting process>
FIG. 12 is a flowchart showing the JAM recovery waiting process in step S1005 of FIG.

  In FIG. 12, after the document D in which JAM has occurred in the image reading apparatus is removed by the operator (YES in step S1902), a confirmation message as to whether or not to continue scanning is displayed on the LCD on the operation panel (step S1902). S1903).

  Next, it is determined whether or not the start button is pressed (step S1904). When the start button is pressed (YES in step S1904), the process returns to step S602 in FIG. The setting value stored in the flash memory is read, and scanning is resumed based on the setting value. On the other hand, when the start button is not pressed (NO in step S1904) and the stop button is pressed (YES in step S1905), a scan end process is executed.

  In this way, the document D staying in the image reading device is removed, placed on the mounting table 4 again, and the start button is pressed, so that the paper feed JAM and the discharge can be performed when the document image is normally read. Even when a paper JAM or the like occurs, it is possible to continue image reading of the subsequent document. Further, it is possible to read a document image without resetting when an operator detects an error.

  According to the above embodiment, since an error recovery process corresponding to the detected error is executed after detecting an error such as double feeding of a document or JAM that has occurred in the image reading apparatus, the operator can respond to the type of error. Thus, it is not necessary to perform post-error processing, and the efficiency of reading can be improved without performing unnecessary resetting and image reading of an original when an error is detected.

  For example, when the JAM recovery waiting process, which is the JAM post-processing, and other multi-feed post-processing, multi-feed recovery waiting process, JAM recovery waiting process, etc. are performed as the next process described above, initial setting by the user is performed in advance. Thus, the user can smoothly execute the next process after feeding abnormality from the operation panel.

  When the next processing is set in this way, if an external device such as a computer to which the image reading device is connected is not notified to the external device of an error such as a feeding abnormality occurring in the image reading device, Notification to external devices can be reduced.

  The present invention is not limited to the above-described embodiment. For example, the present invention can be widely applied to image reading apparatuses as shown in FIGS.

  FIG. 13 is a schematic diagram of an image reading apparatus A according to an embodiment of the present invention, and FIG. 14 is a block diagram of a control unit of the image reading apparatus A.

<Device configuration>
The image reading apparatus A conveys one or a plurality of conveyance media S loaded on the mounting table 1 from the lowest conveyance medium S one by one into the apparatus along a route RT, reads the image, and puts them on the discharge tray 2. It is a device for discharging.

  Here, the transport medium S to be read is, for example, a sheet of OA paper, a check, a check, a business card, a card, etc., and may be a thick sheet or a thin sheet. Examples of the cards include an insurance card, a driver's license, and a credit card. The transport medium S also includes a booklet such as a passport. In the case of targeting a booklet, the holder 200 can be used. By storing the booklet in a spread state in the transparent holder 200 and placing it on the mounting table 1, the booklet is transported together with the holder 200 and the image can be read.

<Feeding>
A first transport unit 10 is provided as a feeding mechanism that feeds the transport medium S along the route RT. In the case of this embodiment, the first transport unit 10 includes a feed roller 11 and a separation roller 12 disposed to face the feed roller 11, and sequentially transports the transport medium S on the mounting table 1 one by one in the transport direction D1. Transport.

  A driving force is transmitted to the feed roller 11 from the driving unit 3 such as a motor through the transmission unit 5 and is rotationally driven in the direction of the arrow in the drawing (the forward direction in which the transport medium S is transported along the path RT). The transmission unit 5 is, for example, an electromagnetic clutch, and interrupts the driving force from the driving unit 3 to the feed roller 11.

<Driver>
For example, in this embodiment, the transmission unit 5 that connects the drive unit 3 and the feed roller 11 is in a state in which the driving force is transmitted in a normal state, and the driving force is applied when the transport medium S is fed back or stopped. Cut off. When the transmission of the driving force is interrupted by the transmission unit 5, the feed roller 11 is in a freely rotatable state. In addition, such a transmission part 5 does not need to be provided when driving the feed roller 11 only in one direction.

<Separation structure>
The separation roller 12 disposed to face the feed roller 11 is a roller for separating the transport medium S one by one, and is in pressure contact with the feed roller 11 with a constant pressure. In order to ensure this pressure contact state, the separation roller 12 is provided so as to be swingable and is urged to the feed roller 11.

  Further, the separation roller 12 is driven to rotate in the direction indicated by the solid line arrow (the direction opposite to the forward direction of the feed roller 11) when the driving force is transmitted from the driving unit 3 via the torque limiter 12a.

  Since the driving force transmission is restricted by the torque limiter 12a, the separation roller 12 rotates in a direction (indicated by a broken arrow) along with the feed roller 11 when contacting the feed roller 11. As a result, when a plurality of transport media S are transported to the pressure contact portion between the feed roller 11 and the separation roller 12, two or more transport media S are blocked so that they are not transported downstream except one. .

  In the present embodiment, the separation roller 12 and the feed roller 11 constitute a separation mechanism. However, such a separation mechanism is not necessarily provided, and the conveyance medium S is sequentially fed to the path RT one by one. Any feeding mechanism may be used. In the case where a separation mechanism is provided, instead of the configuration of the separation roller 12, a separation pad that applies a frictional force to the transport medium S is brought into pressure contact with the feed roller 11 so as to have the same separation action. May be.

<Conveying structure>
The second transport unit 20 as a transport mechanism on the downstream side in the transport direction of the first transport unit 10 includes a drive roller 21 and a driven roller 22 driven by the drive roller 21 and has been transported from the first transport unit 10. The transported medium S is transported downstream.

  Driving force is transmitted to the driving roller 21 from the driving unit 4 such as a motor, and the driving roller 21 is rotationally driven in the direction of the arrow in the figure. The driven roller 22 is brought into pressure contact with the driving roller 21 at a constant pressure, and rotates with the driving roller 21. The driven roller 22 may be configured to be biased against the driving roller 21 by a biasing unit (not shown) such as a spring.

  The third transport unit 30 located downstream of the second transport unit 20 in the transport direction includes a drive roller 31 and a driven roller 32 that is driven by the drive roller 31 and is transported from the second transport unit 20. The transport medium S is transported to the discharge tray 2. That is, the third transport unit 30 functions as a discharge mechanism.

  Driving force is transmitted to the driving roller 31 from the driving unit 4 such as a motor, and the driving roller 31 is rotationally driven in the direction of the arrow in the figure. The driven roller 32 is brought into pressure contact with the driving roller 31 at a constant pressure, and rotates with the driving roller 31. The driven roller 32 may be configured to be biased against the driving roller 31 by a biasing unit (not shown) such as a spring.

  The discharge tray 2 is pivotally supported via a first hinge 101 provided below the image reading device A so as to be rotatable with respect to the image reading device A. Further, it is composed of a first discharge tray 2a on the first hinge 101 side and a first extension tray 2b connected to the tip end side thereof. The first extension tray 2b is slidably supported with respect to the first discharge tray 2a.

<Image reading structure and control>
Here, in the image reading apparatus A of the present embodiment, since the image reading unit 70 disposed between the second transport unit 20 and the third transport unit 30 reads an image, the second transport unit 20 and the second transport unit 20 The three transport unit 30 transports the transport medium S at a constant speed. By always setting the transport speed to be equal to or higher than the transport speed of the first transport unit 10, it is possible to reliably avoid a situation in which the subsequent transport medium S catches up with the preceding transport medium S.

  For example, in this embodiment, speed control is performed so that the transport speed of the transport medium S by the second transport section 20 and the third transport section 30 is faster than the transport speed of the transport medium S by the first transport section 10. did.

  Even when the transport speed of the transport medium S by the second transport section 20 and the third transport section 30 and the transport speed of the transport medium S by the first transport section 10 are the same, the drive section 3 is controlled. It is also possible to form a minimum interval between the preceding transport medium S and the subsequent transport medium S by intermittently shifting the feeding start timing of the subsequent transport medium S.

<Double feed detection>
When the double feed detection sensor 40 disposed between the first transport unit 10 and the second transport unit 20 is in contact with transport media S such as paper due to static electricity or the like, and passes through the first transport unit 10 ( In other words, this is an example of a detection sensor (a sensor for detecting the behavior and state of the sheet) for detecting this in the case of a double feed state in which the sheets are conveyed in an overlapping manner.

  Various sensors can be used as the double feed detection sensor 40, but in the case of the present embodiment, it is an ultrasonic sensor, and includes an ultrasonic transmission unit 41 and a reception unit 42, and is a conveyance medium such as paper. Double feed is detected based on the principle that the attenuation amount of the ultrasonic wave passing through the transport medium S is different between the case where S is transported one by one and the case where S is transported one by one.

<Registration sensor>
The medium detection sensor 50 disposed on the downstream side in the transport direction with respect to the double feed detection sensor 40 is disposed on the upstream side of the second transport unit 20 and on the downstream side of the first transport unit 10. It is an example as an upstream detection sensor (a sensor for detecting the behavior and state of a sheet), and is transported to the position of the transport medium S transported by the first transport unit 10, specifically, to the detection position of the medium detection sensor 50. It is detected whether the end of the medium S has reached or passed.

  As the medium detection sensor 50, various sensors can be used. In the case of the present embodiment, the medium detection sensor 50 is an optical sensor, and includes a light emitting unit 51 and a light receiving unit 52. The transport medium S is detected based on the principle that the intensity (the amount of received light) changes.

  In the case of this embodiment, when the leading edge of the transport medium S is detected by the medium detection sensor 50, the transport medium S reaches the position where the double feed detection sensor 40 can detect double feed. The medium detection sensor 50 is provided on the downstream side in the vicinity of the double feed detection sensor 40.

  The medium detection sensor 50 is not limited to the optical sensor described above. For example, a sensor (image sensor or the like) that can detect the end of the transport medium S may be used, or a lever-type sensor that protrudes into the path RT. It may be a sensor.

  A medium detection sensor 60 different from the medium detection sensor 50 is disposed on the upstream side of the image reading unit 70. This is an example of a downstream detection sensor disposed downstream of the second transport unit 20 and detects the position of the transport medium S transported by the second transport unit 20.

  Various media detection sensors 60 can be used. In the case of the present embodiment, the medium detection sensor 60 is an optical sensor similar to the medium detection sensor 50, and includes a light emitting unit 61 and a light receiving unit 62. The transport medium S is detected based on the principle that the received light intensity (received light amount) changes due to arrival or passage. In the present embodiment, the medium detection sensors 50 and 60 are disposed on the upstream side and the downstream side in the transport direction of the second transport unit 20, respectively, but only one of them may be used.

<CIS layout>
The image reading unit 70 on the downstream side of the medium detection sensor 60 is, for example, optically scanned, converted into an electric signal and read as image data, and internally includes a light source such as an LED, an image sensor, and a lens array. Etc.

  In the present embodiment, one image reading unit 70 is disposed on each side of the path RT, and reads the front and back surfaces of the transport medium S. However, only one side of the route RT may be arranged to read only one side of the transport medium S. Further, in the present embodiment, the image reading unit 70 is configured to be opposed to both sides of the route RT. However, for example, the image reading unit 70 may be arranged with an interval in the direction of the route RT.

<Explanation of block diagram>
The control unit 80 will be described with reference to FIG. FIG. 14 is a block diagram of the control unit 80 of the image reading apparatus A.

  The control unit 80 includes a CPU 81, a storage unit 82, an operation unit 83, a communication unit 84, and an interface unit 85. The CPU 81 controls the entire image reading apparatus A by executing a program stored in the storage unit 82. The storage unit 82 includes, for example, a RAM, a ROM, and the like. The operation unit 83 includes, for example, a switch, a touch panel, and the like, and accepts an operation from the operator.

  The communication unit 84 is an interface that performs information communication with an external device. When a PC (personal computer) is assumed as the external device, examples of the communication unit 84 include a USB interface and a SCSI interface. In addition to such a wired communication interface, the communication unit 84 may be a wireless communication interface, and may include both wired communication and wireless communication interfaces.

  The interface unit 85 is an I / O interface that inputs and outputs data with the actuator 86 and the sensor 87. The actuator 86 includes the drive unit 3, the drive unit 4, the transmission unit 5, and the like. The sensor 87 includes a double feed detection sensor 40, medium detection sensors 50 and 60, an image reading unit 70, and the like.

<Driving by receiving start instruction from PC>
A basic operation of the image reading apparatus A will be described. For example, when receiving an image reading start instruction from an external personal computer to which the image reading apparatus A is connected, the control unit 80 starts driving the first to third transport units 10 to 30. The transport medium S loaded on the mounting table 1 is transported one by one from the transport medium S positioned at the bottom.

  Further, as will be described later, image reading may be started by a start key provided in the operation unit 83 of the image reading apparatus A, and then the start of image reading may be notified to an external personal computer.

<Control during double feeding>
In the middle of the conveyance, the conveyance medium S is determined by the double-feed detection sensor 40 to determine whether or not there is a double-feed, and if it is determined that there is no double-feed, the conveyance is continued. If it is determined that there is a double feed, the transport is stopped or the capture of the subsequent transport medium S by the first transport unit 10 is stopped, and the transport medium S in the double feed state is discharged as it is. It may be.

<Start reading according to the output of the registration sensor>
The control unit 80 starts reading the image by the image reading unit 70 of the transport medium S transported by the second transport unit 20 at a timing based on the detection result of the medium detection sensor 60, and temporarily stores the read image. And send them sequentially to an external computer. The transport medium S from which the image has been read is discharged to the discharge tray 2 by the third transport unit 30, and the image reading process for the transport medium S is completed.

  Here, in the image reading apparatus A of the present embodiment, the encoder 11 as shown in FIGS. 1 and 2 is provided on the left and right driven rollers 22 to detect the presence or absence of the skew of the transport medium S.

  Thus, when the skew of the transport medium S is detected at a portion where the left and right driven rollers 22 are present, the detection result is used to correct the timing based on the detection result of the medium detection sensor 60 serving as a registration sensor.

  Then, based on the timing at which the detection result of the medium detection sensor 60 is corrected, the image reading unit 70 starts to read an image of the transport medium S transported by the second transport unit 20.

  Thereby, it is possible to control the reading start according to the skew of the transport medium S, and it is possible to prevent the image from being missing. Such timing correction for starting image reading can also be applied to the timing for ending reading.

  Also in the image reading apparatus A in the present embodiment, an encoder is arranged on at least one of the rotation shafts of the separation roller 12 and the feed roller 11 so as to detect the movement amount of the document in the separation feeding. By doing so, it is possible to detect early separation defects such as skewing of the original when the originals are fed one by one at the nip portion between the separation roller 12 and the feed roller 11.

  Further, by arranging an encoder on each shaft of the separation roller 12 and the feed roller 11, for example, when the rotation of the encoder on the separation roller 12 side is equivalent to the rotation of the encoder on the feed roller 11 side, for example. Can be used for detecting a feeding abnormality such as a phenomenon of bringing in a plurality of documents and double feeding. On the other hand, when the rotation of the encoder on the separation roller 12 side is relatively small compared to the rotation of the encoder on the feed roller 11 side, it can be determined that the feeding state is normal.

  If such a document separation failure can be detected, for example, it is possible to stop the subsequent conveyance or to stop a predetermined process such as image reading, assuming that the feeding is abnormal.

  In the above-described embodiment, the case where the left and right detection sensors (the first rotation detection sensor and the second rotation detection sensor) detect the arrival and passage of the document D and the movement between them is described as an example. Of course, the present invention is not limited to this. For example, three or more detection sensors may be provided in a direction perpendicular to the document conveyance direction.

  In addition, as the predetermined process to be controlled based on the detection results of the plurality of detection sensors, for example, the image reading has been described as an example in the above-described embodiment. However, the present invention is not limited to this, and for example, It is good also as processing, such as printing and drilling.

  In the above-described embodiment, since the skew of the document can be detected by the left and right detection sensors, the skew obtained based on the detection result of the left and right detection sensors from the document image including the background area read by the image reading sensor. Using the amount, only the document area excluding the background area can be cut out with high accuracy.

D: Document bundle, d1: Lowermost document, 1 ... Document conveying device, 2a ... Lower guide unit, 2b ... Upper guide unit, 3 ... Separation roller, 4 ... Paper feed tray, 5a ... Lower reading sensor, 5b ... Upper reading Sensors 6a, 6b ... Upstream conveying rollers, 7a, 7b ... Downstream conveying roller pairs, 8 ... Pickup rollers, 9 ... Feeding rollers, 10 ... Conveying paths, 11 ... Encoders, 12 ... Roller shafts, 131 ... Detecting units 132 ... Substrate, 14 ... Doppler sensor, 15 ... Registration sensor
t _s … Designed encoder 1 pulse rotation time
t _Rf … Rotation time of the f-th pulse of the right encoder (131R)
t _Lf … Rotation time of the fth pulse of the left encoder (131L)
L _s ... Designed number of pixels of encoder 1 pulse
L ₀ ... Number of pixels in the fth pulse of the left encoder
L _a ... Number of pixels of the f-th pulse of the right encoder
L _k ... the number of pixels of the f-th pulse in any of the line k

Claims (14)

A sheet feeding device that feeds a sheet toward a processing unit that performs predetermined processing on the sheet,
A feeding means for feeding the sheet;
A plurality of detection sensors provided side by side in a direction orthogonal to the sheet feeding direction on the downstream side of the sheet feeding direction of the feeding unit;
Control means for stopping and controlling the driving of the feeding means based on the detection results in the plurality of detection sensors,
The plurality of detection sensors are sensors for detecting a rotation state of a rotating body that rotates following a sheet being fed. Determination means for determining a sheet feeding abnormality based on detection results of the plurality of detection sensors;
Designating means for designating a next process after the judging means judges the sheet feeding abnormality;
When the determination unit determines that the sheet feeding is abnormal, the control unit stops driving the feeding unit, and then executes the next process based on a designation operation from the designation unit. The sheet feeding apparatus according to claim 1.   The sheet feeding apparatus according to claim 2, wherein in the next processing, the feeding unit resumes an operation of feeding a sheet toward a downstream side in the sheet feeding direction.   3. The sheet feeding apparatus according to claim 2, wherein in the next processing, the feeding unit starts an operation of feeding the sheet backward toward the upstream side in the sheet feeding direction.   The next processing is a series of operations in which the feeding unit feeds the sheet toward the downstream side in the sheet feeding direction after performing the operation of feeding the sheet backward toward the upstream side in the sheet feeding direction. The sheet feeding device according to claim 2, wherein the sheet feeding device is a switchback operation.   The sheet feeding apparatus according to claim 2, wherein the next process is a process based on a preset initial setting. A notification means for notifying an external device that the driving of the feeding means has been stopped;
7. The notification unit according to claim 6, wherein when the next process is not set as the initial setting, the notification unit performs notification to the external device or display unit included in the own device. Sheet feeding device. A feeding means for feeding the sheet;
A plurality of detection sensors provided side by side in a direction orthogonal to the sheet feeding direction on the downstream side of the sheet feeding direction of the feeding unit;
A processing unit that is provided downstream of the plurality of detection sensors in the sheet feeding direction and that performs a predetermined process on the sheet;
Control means for stopping and controlling the driving of the feeding means based on the detection results in the plurality of detection sensors,
The plurality of detection sensors are sensors that detect a rotation state of a rotating body that rotates following the sheet being fed,
The sheet processing apparatus, wherein the processing unit performs the predetermined processing on a sheet based on a rotation state of the rotating body detected by the plurality of detection sensors. A transport unit that transports the sheet fed by the feed unit toward the processing unit;
The transport means includes first and second transport rollers that are provided in the axial direction of a drive shaft that is rotationally driven and rotationally driven together with the drive shaft, a first driven roller that is driven to rotate by the first transport roller, and A second driven roller that is driven and rotated by a second transport roller;
9. The rotating body included in the plurality of detection sensors is provided to be rotatable independently of each roller on a rotating shaft of the first and second driven rollers or a driving shaft. The sheet processing apparatus according to 1. The plurality of detection sensors are for detecting arrival and passage of a sheet,
The apparatus according to claim 1, further comprising a control unit that controls driving of the processing unit based on a sheet movement amount obtained based on outputs of the plurality of detection sensors and detection timings of the plurality of detection sensors. The sheet processing apparatus according to 8 or 9.   The control means, based on the detection timings by the plurality of detection sensors, at the timing when the leading edge of the sheet reaches a position upstream in the sheet feeding direction from the processing position by the processing means. The sheet processing apparatus according to claim 10, wherein the start of the processing is controlled.   The control means is based on the detection timings of the plurality of detection sensors, and the processing means by the processing means at a timing when the trailing edge of the sheet reaches a position downstream of the processing position by the processing means in the sheet feeding direction. The sheet processing apparatus according to claim 10, wherein the end of the predetermined process is controlled.   The sheet processing apparatus according to claim 10, wherein the control unit performs control so that the predetermined processing by the processing unit is not performed when detection results of the plurality of detection sensors exceed a predetermined threshold. .   An image reading apparatus that reads an image of a sheet fed by the sheet feeding apparatus according to claim 1.

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