(19)
(11)EP 3 149 927 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.06.2019 Bulletin 2019/26

(21)Application number: 15727145.3

(22)Date of filing:  14.05.2015
(51)International Patent Classification (IPC): 
H04N 1/047(2006.01)
H04N 1/12(2006.01)
(86)International application number:
PCT/US2015/030808
(87)International publication number:
WO 2015/183576 (03.12.2015 Gazette  2015/48)

(54)

SYSTEM AND METHOD FOR MONITORING AND CONTROLLING DOCUMENT VELOCITY IN A SCANNING SYSTEM

SYSTEM UND VERFAHREN ZUR ÜBERWACHUNG UND STEUERUNG DER DOKUMENTGESCHWINDIGKEIT IN EINEM ABTASTSYSTEM

SYSTÈME ET PROCÉDÉ DE SURVEILLANCE ET DE RÉGULATION DE LA VITESSE DE DOCUMENTS DANS UN SYSTÈME DE NUMÉRISATION


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 27.05.2014 US 201414287877

(43)Date of publication of application:
05.04.2017 Bulletin 2017/14

(73)Proprietor: Kodak Alaris Inc.
Rochester, NY 14615 (US)

(72)Inventors:
  • MAYSICK, Randall
    Rochester, New York 14615 (US)
  • REINKE, Stephen M.
    Rochester, New York 14615 (US)
  • WESTCOTT, Robert
    Rochester, New York 14615 (US)

(74)Representative: Vossius & Partner Patentanwälte Rechtsanwälte mbB 
Siebertstrasse 3
81675 München
81675 München (DE)


(56)References cited: : 
US-A- 6 128 106
US-A1- 2005 012 969
US-B1- 6 333 797
US-A1- 2004 114 202
US-A1- 2010 127 447
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    CROSS REFERENCE TO PRIOR APPLICATION



    [0001] This application claims priority to U.S. Patent Application No. 14/287,877; filed May 27, 2014 entitled SYSTEM AND METHOD FOR MONITORING AND CONTROLLING DOCUMENT VELOCITY IN A SCANNING SYSTEM.

    FIELD OF THE INVENTION



    [0002] The present invention relates to document scanning, and in particular to a system and method of providing an improved document velocity along a document transport and past an imaging camera to improve the scanned document image quality.

    BACKGROUND OF THE INVENTION



    [0003] Document image scanners typically include roller systems forming a transport path for a document fed into the scanner to move the document past imaging devices, such as a linear CCD (charged-coupled device) camera. The roller systems generally include multiple rollers, driven by a single motor or multiple motors, which serve to move the documents along the transport path within the scanner. Typically, when a stack of documents are fed into the entrance of a scanner, they first encounter an urging roller which urges a stack of documents to an adjacent feed roller, which mates with a separation device. The separation device provides a recessive force to the lead edge of a stack of documents and separates a single document from the stack and then advances the single document to transport rollers and past the camera.

    [0004] However, documents fed through the scanner may cause the different rollers to turn at different velocities. This can lead to transport slippage, misfeeds, and a reduction in image quality. For example, when the trailing edge of a document leaves the separation device the scanner transport may speed up slightly due to the reduction in load on the drive system. These changes in transport speed cause the document to move past the cameras at different speeds, resulting in reductions in image quality. In typical document image scanners which utilize a linear CCD camera, a constant velocity of the document being imaged past the camera is desired, to achieve the best image quality.

    [0005] What is needed is a system and method to monitor the velocity of the transport system, and in particular the velocity of the rollers within the system. The velocity of various rollers within the system may then be controlled at various times, such as when a document is entering or leaving a new set of rollers, in order to reduce slippage, jams, and improve image quality.

    [0006] US 2005/012969 (A1) pertains to a original reading device having an automatic document feeding function in which a rotary motion controller causes an original feed roller to rotate when the rear part of an original passes over the original feed roller. When the original feed roller rotates in this way, the rear part of the original is pushed downstream in an original feeding direction. If the circumferential speed of the original feed roller is higher than the circumferential speed of a registration roller, the original slacks before the rear part of the original passes beyond the original feed roller so that original becomes less susceptible to the load fluctuation when the rear part of the original is released and, as a consequence, unevenness in the original transport speed becomes less likely to occur.

    [0007] US 6 333 797 (B1) relates to a document feeder which picks up stacked documents one by one and feeds each document on an image reading position over a stationary image reading device at a constant speed.

    [0008] US 6 128 106 (A) relates to a sheet conveying apparatus which can correct a conveying velocity of a sheet.

    [0009] US 2004/114202 (A1) relates to an image scanning apparatus having a function of scanning a flowing image of a document fed at predetermined speed.

    [0010] US 2010/127447 (A1) relates to a document transport apparatus for ordered stacking of scanned documents of various sizes.

    SUMMARY OF THE INVENTION



    [0011] The invention provides a system according to claim 1 and a method according to claim 8. Further features are defined in the dependent claims. The velocity of the rollers may be monitored, and a controller may be provided to adjust the motors driving the rollers, thereby controlling the speed. By monitoring and controlling the velocity profile of the transport system, the scanning system may provide higher image quality and may reduce slippage, misfeeds and jams, and provide alerts to an operator in the event slippage, misfeeds, or jams do occur.

    [0012] Sensors may be provided to detect the speed of the rollers, and to detect the position of documents transported within the system. For example, document detection sensors may be provided to sense the leading and trailing edges of documents as they move through the transport system. These sensors may detect when a document enters and leaves various rollers, or when it moves past certain components within the system. By tracking the leading and trailing edges of the documents, the scanner may know when to adjust the speed of the rollers or feed the next document from the stack into the scanner.

    [0013] In addition, monitoring of the scanner transport speed may allow the system to predict when the leading edge of the document should be received at various locations. If the leading edge is not sensed at these locations at the expected time, an alert may be provided to the operator that there is a potential jam or misfeed within the scanning system. These early alerts may reduce the amount of jam damage done, and provide increased accuracy as to the location of the jam. Additional features of the scanner may be monitored and controlled based on the detected speeds along the transport path and detected document edges.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0014] 

    FIGURE 1 is a schematic of a scanning system in accordance with an embodiment of the invention that includes a block diagram of the control electronics.

    FIGURE 2 is a cross section perspective view of a scanning system in accordance with an embodiment of the invention.

    FIGURE 3 is view of the gear arrangement between the feeder roller and urging roller.

    FIGURE 4A is a diagram illustrating the typical velocity of a document fed in a typical scanning system transport.

    FIGURE 4B is a diagram illustrating the constant velocity of the transport drive motor in the typical scanning system transport.

    FIGURE 4C is a diagram illustrating the resulting velocity of the document at the imaging camera being imaged in the typical scanning transport system.

    FIGURE 5A is another diagram illustrating the typical velocity of a document fed in the scanning system transport.

    FIGURE 5B is a diagram illustrating the adjusted velocity of the transport drive motor in a system implementing aspects of the present invention to monitor and control velocity within the scanning system.

    FIGURE 5C is a diagram illustrating the resulting constant velocity of the document at the imaging camera being imaged by implementing the velocity control according to aspects of the present invention.

    FIGURE 6A is a diagram illustrating another typical velocity of a document fed in the scanning system transport.

    FIGURE 6B is a diagram illustrating the adjusted velocity of the transport drive motor in a system implementing aspects of the present invention to monitor and control velocity within the scanning system.

    FIGURE 6C is a diagram illustrating the resulting improved velocity of the document at the imaging camera being imaged by implementing the velocity control according to aspects of the present invention.


    DETAILED DESCRIPTION OF THE INVENTION



    [0015] The present invention is directed to systems and methods for scanning documents, and for and controlling roller speed along the transport path. The scanning system 10, shown in FIGURES 1 and 2 includes an input tray 14 which supports a document stack 12 that will be separated and driven through the scanning system 10. A motor 30 and clutch 34 are controlled by a motion controller 48 for feeding a document 52 from the document stack 12 and into a series of rollers configured to move the document 52 through the scanning system 10 and past imaging cameras 36A and 36B. As the document is fed past the cameras, its image data is captured and transferred by a control logic processor 28 and then to memory 50. Typically, an urging roller 16 is the first roller at the entrance of the scanning system 10 and makes initial contact with all documents in the document stack 12 being fed along the transport path 22 for imaging. The urging roller 16 has a mating urging pinch roller 18 which provides a nip force against the document stack 12 and the urging roller 16. The nip force helps to insure the urging roller 16 rotates without slippage on the document 52 being fed through this nip. The scanning system 10 includes an urging roller sensor 42 and an urging roller encoder wheel 44, which is rigidly attached to the urging roller 16, to monitor the velocity of the urging roller 16.

    [0016] The scanning system's motor 30 drives the clutch 34 which in turn drives the feed roller drive shaft 40 when the clutch 34 is energized. The feed roller 20 is pivotally mounted on the feed roller drive shaft 40 via a mechanical one-way clutch bearing (not shown), which allows the feed roller 20 to be driven by the clutch 34 as well as be pulled by the document 52 which is transported along the transport path 22. The motor 30 also drives the first and exit transport rollers 24, 26 typically with a belt or gear arrangement (not shown). The urging roller 16 is also pivotally mounted on a mechanical one-way bearing (not shown) which is supported on the urging roller drive shaft 17. The urging drive shaft 17 is driven via a gear arrangement 32, shown in FIGURE 3, which is in turn driven by the feed roller drive shaft 40. This described configuration allows both the urging and feed rollers 16, 20 to be driven at different speeds by the motor 30 and gear arrangement 32. Also this configuration allows the document 52 to pull both the urging and feed rollers 16, 20 at a faster rate of speed (than their motor driven speed) by the document 52 traveling in the transport rollers.

    [0017] The urging roller encoder wheel 44 may be comprised of a small wheel with slots for the urging roller sensor 42 to optically detect. In this embodiment of the invention, the urging roller sensor 42 is a photoelectric through beam sensor which looks through the slots in the urging roller encoder wheel 44. Other sensor types and wheel configurations may also be used to achieve the desired result, such as reflective sensors or magnetic sensors. The urging roller sensor 42, with some signal amplification and conditioning, provides a number of positive and negative transitions, corresponding to the number of slots, per revolution. The urging roller 16 diameter and transport velocity may be considered in determining an encoder frequency. For example, the urging roller 16 may be approximately 1.06" in diameter or 3.33" in circumference, the urging roller encoder wheel 44 may have forty slots, and the transport velocity may 10.5"/second. Considering only the position transitions, the encoder frequency for this example is (10.5/3.33) x 40 = 126 Hz. However, the urging roller sensor 42 frequency is not constant. It starts out slow (urging roller 16 speed), then speeds up when the lead edge of the document 52 enters the nip of feed roller 20, then nearly doubles in speed when the lead edge of the document 52 enters the first transport roller 24 nip. The urging roller 16 tangential velocity is 67% of the feed roller 20, which is in turn 52% of the first transport roller 24 and exit transport rollers 26.

    [0018] The nature of the construction of the urging roller encoder wheel 44 and possible contamination may lead to frequency flutter or occasional missing transitions. Therefore, it may be important to have a method to ignore frequency flutter or occasional missing transitions with a time domain filter. For example, an 8-bit counter may be used and a fixed clock may increment the counter. The encoder clock will reset the counter to zero. If the encoder clock stops, the counter will increment via the fixed clock to a terminal count, such as 4. This terminal count indicates that enough time has passed with no encoder clock to be interpreted as a stoppage of the urging roller. Reaching the terminal count will generate a signal to start the timer or distance counter to predict when the trail edge of the document reaches the feed nip. This time (in distance) is the urging roller to feed roller nip distance (29.0 mm), minus the latency of the counter filter. While the urging roller encoder wheel 44 is turning, the typical count sequence will be 0 1 0 1 0 1 as the fixed clock increments to 1 and the encoder resets to zero. If a few pulses are missing, the sequence will be 0 12 3 0 1 0 1. The fixed clock may be biased in a way that increments the counter to be lower than the urging encoder clock. The fixed clock may be unique for each transport speed used.

    [0019] One or multiple motors 30 are provided to drive the various rollers in the system. The urging roller 16 is driven by a at a slower rotational speed than the next feed roller 20 via a gear arrangement 32 that is connected to the feed roller and urging roller shafts 40, 17. For example, the urging roller 16 may be driven at 66% of speed of the feed roller 20. Both the urging roller 16 and feed roller 20 are supported on one-way bearings (not shown), which allows both rollers to be driven forward by their mating shafts (40,17) and which also allows both rollers to rotate faster than their "driven" speeds when a document 52 in their associated nips is transported (pulled) at a faster transport speed.

    [0020] The feed roller 20 may be engaged with a fixed elastomeric pad (known as a separation pad) or a separation roller (also known as a retard roller that provides a drag force on the document being transported), thereby creating one separation nip. Alternatively, the feed roller 20 may also be engaged with multiple separation devices 21, such as a fixed pad and a separation roller, thereby creating two separation nips. These nips provide separation force on a stack of documents and are designed to allow only one of the documents 52 in contact with the feed roller 20 and urging roller 16 to be fed into the first transport roller 24 (also called the takeaway roller).

    [0021] The third nip in the scanning system 10 is the first transport roller 24 and it's mating normal force roller, which is driven at the scanning system transport and cameras 36A, 36B scanning speed. The first transport roller 24 nip driven speed is faster than the feed roller 20 driven nip speed (for example the feed roller 20 nip speed may be 55% of the first transport roller 24 speed) and the feed roller 20 nip speed is faster than the urging roller 16 driven nip speed.

    [0022] Imaging cameras 36A, 36B are included in the transport path after the first transport roller 24 nip, and are capable of detection of the document 52 lead and trailing edge. After the cameras 36A, 36B, there is an exit transport roller 26 nip that is driven at the same speed as the first transport roller 24 nip. This nip releases the fed documents 52 out of the scanning system 10 after the images are obtained.

    [0023] In addition to the urging roller sensor 42, the scanning system 10 may have additional sensors after the feed roller 20 nip which can detect the leading or trailing edge of the document 52 being transported. These sensors may be of many types, including ultrasonic sensors or photoelectric.

    [0024] The urging roller sensor 42 can sense whether a fed document's 52 lead edge speeds up as it enters the feed roller 20 nip by monitoring the urging roller 16 velocity change. It can also sense whether the fed document's lead edge speeds up as it enters the first transport roller 24 nip by monitoring this velocity speed up. The urging roller sensor 42 may also monitor the amount of speed change, and the current speeds of the rollers within the scanning system 10. In addition, the trailing edge of the document fed into the scanner can be sensed at the urging roller 16 nip when it is pulled out of this nip and the urging roller sensor 42 senses a stop in the rotation of the urging roller 16. The urging roller sensor will issue a "roller stopped" signal to indicate that the roller has stopped rotating after a predetermined number of counts without a change in the sensed state of the urging roller. Alternatively, the "roller stopped" signal may be issued after a predetermined time period elapses without a change in the sensed state of the urging roller. This technique provides the capability of the urging roller sensor 42 to be a "document location sensor" by sensing the trailing edge of the fed document 52.

    [0025] The scanning system 10 includes an auto-document feeding (ADF) system, in which the feed roller 20 nip and urging roller 16 nip section of the scanning system 10 are driven by a main transport motor 30 through an electromagnetic clutch 34. The clutch 34 is energized to drive the urging and feed roller 16, 20 and feed the document 52 to the first transport roller nip 24. When the lead edge of the fed document 52 is in the first transport roller 24 nip, the clutch 34 can be disengaged. When the clutch 34 is disengaged the first transport roller 24 nip and then the exit transport roller 26 nip pull the trailing portion of the document 52 through the urging and feed nips. When the document location sensor 38 senses that the trailing edge of the fed document 52, the clutch 34 can be re-energized to feed the next document 52 from the document stack 12.

    [0026] By monitoring the scanning system 10 with the urging roller sensor 42, the systems and methods described herein allow for improved image quality, reduction in jams, reductions in slippage, reductions in misfeeds, and improved operator alerts identifying problems.

    [0027] The scanning system 10 roller transport speed may be adjusted based on the detection of the trailing edge of the fed document 52. Typically when the fed document's 52 trailing end leaves the separation device 21 nip, the scanning systems first and exit transport rollers 24,26 will speed up slightly, because of the reduction of separation drag force on the transported document 52 causes a slight increase in the actual velocity of the document 52. For example, the scanning system transport may speed up by around 1 % because of the sudden release of the separation drag force on the document 52 which was under tension. However, in order to maintain the best image quality, it is desired to keep the document 52 being imaged at a constant velocity within the scanning system 10. In order to achieve this, the transport motor 30 velocity clock may be switched from a higher frequency that accounts for separation device 21 drag force to a lower speed at the time of the document 52 releases from the separation device 21 nip. The magnitude of this frequency change may be small, such as about 1.5%, but it is sufficient to provide a more uniform velocity profile for longer documents 52 and enhance magnification accuracy in the document travel direction by a significant amount. This function is beneficial for all transport speeds, which is often needed for different scanning resolutions. The end of the document 52 can be detected in advance of its release from the separation device 21 nip by using the urging roller sensor 42 and knowing the programmed transport speed and distance the urging roller 16 nip is from the separation device 21 nip. As mentioned above, this release may cause the scanning system 10 to speed up, resulting in a loss of image quality of the scanned document. Thus, the transport speed adjustment can be made near the time of the separation device 10 nip release to correct this velocity error for any length document. This adjustment can improve the document 52 captured image length to match the original document 52 length, thereby greatly reducing the effects of the separation device 21 on the velocity of the rollers, transport components, and documents 52. This correction may be especially important for longer documents.

    [0028] The systems and methods may also allow for jam detection of the fed document 52 based on lead edge detection. The lead edge of the fed document 52 may be detected at the feed roller nip by monitoring the urging roller sensor 42 speed up frequency. There is a known time in which the lead edge of the document should get to the document location senor 38, first transport roller 24 or imaging cameras 36A, 36B, because the nip speeds and distances are known between each component. Jams of the lead edge of fed documents can be sensed if the lead edge is not at one of these locations at a predetermined time. Thus, monitoring the velocity of the system and the location of the document within the system may increase the location accuracy of sensed jams, and may reduce the amount of jam damage done to the fed document 52, by stopping the feeding process when a jam is sensed. The scanning system 10 may automatically stop the feeding process when such a jam is sensed, or provide an alert to an operator that a jam is present.

    [0029] The present invention may also allow for detection if a document stack 12 is present in the scanning system input tray 14, and detection of the last document being fed from a document stack 12. The insertion of document stack 12 or a single document 52 into the scanner will rotate the urging roller 16 and provide a signal that documents have been inserted. After the last document 52 has left the scanning system 10 and the clutch 34 is turned on in an attempt to feed another document, the urging roller 16 will not begin to rotate at a faster speed at the predicted time as it would if a document was present in the urging roller nip. Therefore, the system can detect there are no more documents to feed, and the document stack 12 has been completely fed through the scanning system. This technique can be used for end of stack detection.

    [0030] In addition to detection of documents, the present invention may detect transport roller slippage, which could impact image quality. If there is significant slippage of the document 52 in the first transport roller nip, which may be caused by non-carbon copy paper dirt for example on the rollers, the urging roller 16 speed will rotate at a slower rate than predicted based on the first transport roller 24 (also called the takeaway roller) driven nip speed. By detecting that urging roller 16 is rotating at a slower predicted rate, the scanning system will know that slippage of the document 52 is occurring, and can alert the operator.

    [0031] The urging roller sensor 42 can also be used to monitor the clutch 34 engagement profile when the clutch 34 is energized to see if it is behaving according to specified parameters. For example, the clutch 34 engagement may be monitored to ensure it is not slipping. After the clutch 34is energized, it should rotate the feed and urging rollers 20, 16 at the driven speed in an expected, repeatable manner over the life of the clutch 34. Both initial installation evaluation and long term monitoring of this clutch 34 engage profile can be performed using the urging roller sensor 42.

    [0032] When the ADF clutch 34 is de-energized, the feed and urging roller drive shafts 40,17 should not rotate. If they rotate when the clutch is de-energized, some frictional driving torque is likely being transmitted to the feed and urging roller 20,16 by the clutch, which is not desirable. If this condition occurs, the trailing edge of the fed document 52 is pulled off the urging roller 16, and the next document in the document stack 12 can be urged forward while the first fed document is still within the feeder roller nip. This condition will cause the lead section of the next fed document to buckle, which can cause jams for thin paper types (rice paper for example). Both initial installation evaluation and long term monitoring of this condition can be performed using the urging roller sensor 42.

    [0033] Figures 4A-4C illustrate the velocity within a traditional scanning system. Referring to FIGURE 4A, the typical change in the document velocity from V1 to V2 can be seen. This change in document velocity occurs when the trailing end of the document is released from the separation device. The corresponding typical constant velocity V3 of the scanning systems drive motor is shown in FIGURE 4B. Because of the release of the separation force on the document trailing end happens when the document's image is being captured, a change in the documents velocity from V5 to V6 at the imaging camera is typically seen (Refer to FIGURE 4C). This small change in velocity (typically less than 2%) can impact the image length of the document as well as the geometric accuracy of the image. Therefore, scanned images from documents fed through traditional scanning systems using a constant motor velocity, as illustrated in Figures 4A-4C, may experience distortion and loss of image quality due to the changes in velocity as the documents move past the image capturing devices.

    [0034] As discussed above, aspects of the present invention monitor and control the velocity of the document scanning system to provide higher image quality and reduce slippage, misfeeds and jams. Figures 5A-5C and 6A-6C illustrate the improved, more constant document velocity at the image capture devices that may be obtained by controlling the motor velocity to account for expected velocity changes within the scanning device as the documents enter and leave the various rollers.

    [0035] Referring to FIGURE 5A, the typical "expected" change in the document velocity from V1 to V2 is shown that occurs when the trailing end of the document is released from the separation device. In order to compensate for this expected change in velocity, adjustments to the motor velocity may be made as described above. An adjusted velocity V3 to V4 of the scanning systems drive motor is shown in FIGURE 5B. This change V3 to V4 in motor velocity coincides with the exact change in the document typical velocity change V1 to V2. Also, because the magnitude of the motor velocity adjustment change is equal to that of the document in FIGURE 5A, the resulting "actual" document velocity at the imaging cameras is at an ideal constant velocity V7, which is seen in FIGURE 5C. These associated figures illustrate the ideal result of this embodiment of the invention, which is a constant document imaging velocity during the entire length of the document.

    [0036] However, even if the magnitude or the exact timing of this scanning system drive motor adjustment is not ideal, it can still result in improved imaging velocities as illustrated in FIGURES 6A, 6B, and 6C as compared to no scanning system drive motor adjustment, as shown in FIGURES 4A, 4B and 4C. Note that the improved change in velocity V5' to V6' as shown in FIGURE 6C, has been reduced as compared to the change in document velocity V5 to V6 being imaged as shown in FIGURE 4C in a standard scanning transport with no velocity correction. Even if there are variations in the magnitude and timing of the document expected velocity change, the motor programmed velocity adjustment can greatly improve the document's resulting image quality by counter acting the change in scanning system transport speed that is typically seen when the document is released for the feed roller separation device nip.

    PARTS LIST



    [0037] 
    10
    scanning system
    12
    document stack
    14
    input tray
    16
    urging roller
    17
    urging roller drive shaft
    18
    urging pinch roller
    20
    feed roller
    21
    separation device
    22
    transport path
    24
    first transport roller
    26
    exit transport roller
    28
    control logic processor
    30
    motor
    32
    gear arrangement
    34
    clutch
    36A
    camera
    36B
    camera
    38
    document location sensor
    40
    feed roller drive shaft
    42
    urging roller sensor
    44
    urging roller encoder wheel
    48
    motion controller
    50
    memory
    52
    document



    Claims

    1. A system for providing an improved document velocity along a document transport path in a scanning system comprising:

    (a) a roller system (16, 18, 20, 24, 26) comprising a roller for conveying a document along the document transport path;

    (b) a motor (30) for driving the roller with a motor velocity;

    (c) a document location sensor (38) for detecting an edge of the document; and

    (d) a processor (28) configured to:

    (i) monitor a velocity profile of the document transport path; and

    (ii) control the motor velocity;

    wherein the processor (28) is configured to decrease the motor velocity to compensate for expected changes in velocity of the document along the transport path, thereby conveying the document at a more constant velocity along the document transport path;
    wherein the roller system (16, 18, 20, 24, 26) includes an urging roller (16) for urging the document into the document transport path and a separation device (21) for separating individual sheets of documents;
    wherein the document location sensor (38) detects a trailing edge of the document;
    wherein the processor is configured to decrease the motor velocity at a time when the trailing edge of the document is released from a nip of the separation device (21) to compensate for an expected change in velocity of the document due to release from the nip of the separation device (21),
    wherein the urging roller (16) has an urging roller sensor (42) that is configured to detect the trailing edge of the document by sensing a stop in a rotation of the urging roller (16), and
    wherein the processor is configured to calculate the time to decrease the motor velocity using the detected trailing edge of the document, the distance from a nip of the urging roller (16) to the nip of the separation device (21), and a programmed transport speed.
     
    2. The system of claim 1,
    wherein the processor is configured to decrease the motor velocity in response to detecting the movement of the trailing edge of the document along the document transport path.
     
    3. The system of claim 1, wherein the document location sensor (38) detects a leading edge of the document.
     
    4. The system of claim 1, wherein the processor (28) further monitors the velocity profiles of previous passages of other documents along the document transport path.
     
    5. The system of claim 4, wherein the processor (28) is further configured to modify the motor velocity to compensate for expected changes in velocity of the document along the document path based on the velocity profiles of the previous passages of other documents along the transport path.
     
    6. The system of claim 3, wherein the processor (28) is configured to modify the motor velocity after the leading edge of the document is detected.
     
    7. The system of claim 1, wherein the processor (28) is configured to modify the motor velocity after the trailing edge of the document is detected.
     
    8. A method of improving document velocity along a document transport path in a scanning system comprising:

    (a) conveying the document with a roller system (16, 18, 20, 24, 26) comprising a roller along the document transport path;

    (b) driving the roller with a motor (30), wherein the motor (30) operates at a variable motor velocity;

    (c) detecting an edge of the document with a document location sensor (38);

    (d) monitoring a velocity profile of the document transport path;

    (e) controlling the motor velocity; and

    (f) decreasing the motor velocity to compensate for expected changes in velocity of the document along the document path, thereby conveying the document at a more constant velocity along the document transport path,

    wherein conveying the document with a roller system (16, 18, 20, 24, 26) includes urging the document into the document transport path with an urging roller (16) and separating individual sheets of documents with a separation device (21),
    wherein detecting an edge of the document includes detecting a trailing edge of the document;
    wherein the motor velocity is decreased at a time when a trailing edge of the document is released from a nip of the separation device (21) to compensate for an expected change in velocity of the document due to release from the nip of the separation device (21),
    wherein the urging roller (16) has an urging roller sensor (42) detecting the trailing edge of the document by sensing a stop in a rotation of the urging roller (16), and
    wherein the time to decrease the motor velocity is calculated using the detected trailing edge of the document, the distance from a nip of the urging roller (16) to the nip of the separation device (21), and a programmed transport speed.
     
    9. The method of claim 8, wherein detecting an edge of the document includes detecting a leading edge of the document.
     
    10. The method of claim 8, further comprising monitoring the velocity profiles of previous passages of other documents along the document transport path.
     
    11. The method of claim 8, further comprising modifying the motor velocity to compensate for expected changes in velocity of the document along the document path based on the velocity profiles of previous passages of other documents along the document transport path.
     
    12. The method of claim 9, further comprising modifying the motor velocity after the leading edge of the document is detected.
     
    13. The method of claim 8, further comprising modifying the motor velocity after the trailing edge of the document is detected.
     


    Ansprüche

    1. System zum Bereitstellen einer verbesserten Dokumentgeschwindigkeit entlang eines Dokumenttransportpfads in einem Abtastsystem mit:

    (a) einem Walzensystem (16, 18, 20, 24, 26) mit einer Walze zum Transportieren eines Dokuments entlang des Dokumenttransportpfads,

    (b) einem Motor (30) zum Antreiben der Walze mit einer Motorgeschwindigkeit,

    (c) einem Dokumentpositionssensor (38) zum Erfassen einer Kante des Dokuments, und

    (d) einem Prozessor (28), der ausgebildet ist

    (i) ein Geschwindigkeitsprofil des Dokumenttransportpfads zu überwachen und

    (ii) die Motorgeschwindigkeit zu steuern,

    wobei der Prozessor (28) ausgebildet ist, die Motorgeschwindigkeit zu verringern, um erwartete Änderungen der Geschwindigkeit des Dokuments entlang des Dokumenttransportpfads auszugleichen, so dass das Dokument mit einer konstanteren Geschwindigkeit entlang des Dokumenttransportpfads transportiert wird,
    wobei das Walzensystem (16, 18, 20, 24, 26) eine Antriebswalze (16) zum Bewegen des Dokuments in den Dokumenttransportpfad und eine Trennvorrichtung (21) zum Trennen einzelner Seiten der Dokumente aufweist,
    wobei der Dokumentpositionssensor (38) eine Hinterkante des Dokuments erfasst,
    wobei der Prozessor ausgebildet ist, die Motorgeschwindigkeit zu einem Zeitpunkt zu reduzieren, an dem die Hinterkante des Dokuments aus einem Walzenspalt der Trennvorrichtung (21) freigegeben wird, um eine erwartete Änderung der Geschwindigkeit des Dokuments aufgrund der Freigabe aus dem Walzenspalt der Trennvorrichtung (21) auszugleichen,
    wobei die Antriebswalze (16) einen Antriebswalzensensor (42) aufweist, der ausgebildet ist, die Hinterkante des Dokuments zu erfassen, indem ein Stoppen einer Rotation der Antriebswalze (16) abgetastet wird, und
    wobei der Prozessor ausgebildet ist, die Zeit für das Verringern der Motorgeschwindigkeit unter Verwendung der erfassten Hinterkante des Dokuments, des Abstands zwischen einem Walzenspalt der Antriebswalze (16) und dem Walzenspalt der Trennvorrichtung (21) und einer programmierten Transportgeschwindigkeit zu berechnen.
     
    2. System nach Anspruch 1,
    wobei der Prozessor ausgebildet ist, die Motorgeschwindigkeit in Antwort auf ein Erfassen der Bewegung der Hinterkante des Dokuments entlang des Dokumenttransportpfads zu verringern.
     
    3. System nach Anspruch 1, wobei der Dokumentpositionssensor (38) eine Vorderkante des Dokuments erfasst.
     
    4. System nach Anspruch 1, wobei der Prozessor (28) ferner die Geschwindigkeitsprofile früherer Transporte von anderen Dokumenten entlang des Dokumenttransportpfads überwacht.
     
    5. System nach Anspruch 4, wobei der Prozessor (28) ferner ausgebildet ist, die Motorgeschwindigkeit anzupassen, um erwartete Änderungen der Geschwindigkeit des Dokuments entlang des Dokumentpfads basierend auf den Geschwindigkeitsprofilen der früheren Transporte anderer Dokumente entlang des Transportpfads auszugleichen.
     
    6. System nach Anspruch 3, wobei der Prozessor (28) ausgebildet ist, die Motorgeschwindigkeit anzupassen, nachdem die Vorderkante des Dokuments erfasst wurde.
     
    7. System nach Anspruch 1, wobei der Prozessor (28) ausgebildet ist, die Motorgeschwindigkeit anzupassen, nachdem die Hinterkante des Dokuments erfasst wurde.
     
    8. Verfahren zum Verbessern der Dokumentgeschwindigkeit entlang eines Dokumenttransportpfads in einem Abtastsystem mit den Schritten:

    (a) Transportieren des Dokuments mit einem Walzensystem (16, 18, 20, 24, 26) mit einer Walze entlang des Dokumenttransportpfads,

    (b) Antreiben der Walze mit einem Motor (30), wobei der Motor (30) mit einer variablen Motorgeschwindigkeit betrieben wird,

    (c) Erfassen einer Kante des Dokuments durch einen Dokumentpositionssensor (38),

    (d) Überwachen eines Geschwindigkeitsprofils des Dokumenttransportpfads,

    (e) Steuern der Motorgeschwindigkeit, und

    (f) Verringern der Motorgeschwindigkeit, um erwartete Änderungen der Geschwindigkeit des Dokuments entlang des Dokumenttransportpfads auszugleichen, so dass das Dokument mit einer konstanteren Geschwindigkeit entlang des Dokumenttransportpfads transportiert wird,

    wobei das Transportieren des Dokuments mit einem Walzensystem (16, 18, 20, 24, 26) das Bewegen des Dokuments in den Dokumenttransportpfad durch eine Antriebswalze (16) sowie das Trennen einzelner Seiten der Dokumente durch eine Trennvorrichtung (21) aufweist,
    wobei das Erfassen einer Kante des Dokuments ein Erfassen einer Hinterkante des Dokuments aufweist,
    wobei die Motorgeschwindigkeit zu einem Zeitpunkt reduziert wird, an dem die Hinterkante des Dokuments aus einem Walzenspalt der Trennvorrichtung (21) freigegeben wird, um eine erwartete. Änderung der Geschwindigkeit des Dokuments aufgrund der Freigabe aus dem Walzenspalt der Trennvorrichtung (21) auszugleichen, wobei die Antriebswalze (16) einen Antriebswalzensensor (42) aufweist, der die Hinterkante des Dokuments erfasst, indem ein Stoppen einer Rotation der Antriebswalze (16) abgetastet wird, und
    wobei die Zeit für das Verringern der Motorgeschwindigkeit unter Verwendung der erfassten Hinterkante des Dokuments, des Abstands zwischen einem Walzenspalt der Antriebswalze (16) und dem Walzenspalt der Trennvorrichtung (21) und einer programmierten Transportgeschwindigkeit berechnet wird.
     
    9. Verfahren nach Anspruch 8, wobei das Erfassen einer Kante des Dokuments das Erfassen einer Vorderkante des Dokuments aufweist.
     
    10. Verfahren nach Anspruch 8, ferner mit dem Schritt des Überwachens der Geschwindigkeitsprofile früherer Transporte anderer Dokumente entlang des Dokumenttransportpfads.
     
    11. Verfahren nach Anspruch 8, ferner mit dem Schritt des Anpassens der Motorgeschwindigkeit, um erwartete Änderungen der Geschwindigkeit des Dokuments entlang des Dokumentpfads basierend auf den Geschwindigkeitsprofilen der früheren Transporte anderer Dokumente entlang des Transportpfads auszugleichen.
     
    12. Verfahren nach Anspruch 9, ferner mit dem Schritt des Anpassens der Motorgeschwindigkeit, nachdem die Vorderkante des Dokuments erfasst wurde.
     
    13. Verfahren nach Anspruch 8, ferner mit dem Schritt des Anpassens der Motorgeschwindigkeit, nachdem die Hinterkante des Dokuments erfasst wurde.
     


    Revendications

    1. Système pour fournir une vitesse de document améliorée le long d'une trajectoire de transport de document dans un système de balayage, comprenant :

    (a) un système de rouleau (16, 18, 20, 24, 26) comprenant un rouleau pour transporter un document le long de la trajectoire de transport de document ;

    (b) un moteur (30) pour entraîner le rouleau avec une vitesse de moteur ;

    (c) un capteur d'emplacement de document (38) pour détecter un bord du document ; et

    (d) un processeur (28) configuré pour :

    (i) surveiller un profil de vitesse de la trajectoire de transport de document ; et

    (ii) contrôler la vitesse du moteur ;

    dans lequel le processeur (28) est configuré pour réduire la vitesse du moteur afin de compenser les changements attendus de vitesse du document le long de la trajectoire de transport, transportant ainsi le document à une vitesse plus constante le long de la trajectoire de transport de document ;
    dans lequel le système de rouleau (16, 18, 20, 24, 26) comprend un rouleau de poussée (16) pour pousser le document dans la trajectoire de transport de document et un dispositif de séparation (21) pour séparer les feuilles individuelles de documents ;
    dans lequel le capteur d'emplacement de document (38) détecte un bord de fuite du document ;
    dans lequel le processeur est configuré pour réduire la vitesse du moteur au moment où le bord de fuite du document est libéré d'une ligne de pincement du dispositif de séparation (21) afin de compenser un changement attendu de vitesse du document dû à la libération de la ligne de pincement du dispositif de séparation (21),
    dans lequel le rouleau de poussée (16) a un capteur de rouleau de poussée (42) qui est configuré pour détecter le bord de fuite du document en détectant un arrêt dans une rotation du rouleau de poussée (16), et
    dans lequel le processeur est configuré pour calculer le temps pour réduire la vitesse du moteur en utilisant le bord de fuite détecté du document, la distance allant d'une ligne de pincement du rouleau de poussée (16) jusqu'à la ligne de pincement du dispositif de séparation (21), et une vitesse de transport programmée.
     
    2. Système selon la revendication 1,
    dans lequel le processeur est configuré pour réduire la vitesse du moteur en réponse à la détection du mouvement du bord de fuite du document le long de la trajectoire de transport de document.
     
    3. Système selon la revendication 1, dans lequel le capteur d'emplacement de document (38) détecte un bord d'attaque du document.
     
    4. Système selon la revendication 1, dans lequel le processeur (28) surveille en outre les profils de vitesse des précédents passages des autres documents le long de la trajectoire de transport de document.
     
    5. Système selon la revendication 4, dans lequel le processeur (28) est en outre configuré pour modifier la vitesse du moteur afin de compenser les changements attendus de vitesse du document le long de la trajectoire de document sur la base des profils de vitesse des précédents passages des autres documents le long de la trajectoire de transport.
     
    6. Système selon la revendication 3, dans lequel le processeur (28) est configuré pour modifier la vitesse du moteur après que le bord d'attaque du document a été détecté.
     
    7. Système selon la revendication 1, dans lequel le processeur (28) est configuré pour modifier la vitesse du moteur après que le bord de fuite du document a été détecté.
     
    8. Méthode pour améliorer la vitesse de document le long d'une trajectoire de transport de document dans un système de balayage, comprenant les étapes suivantes :

    (a) transporter le document avec un système de rouleau (16, 18, 20, 24, 26) comprenant un rouleau le long de la trajectoire de transport de document ;

    (b) entraîner le rouleau avec un moteur (30), dans lequel le moteur (30) fonctionne à une vitesse de moteur variable ;

    (c) détecter un bord du document avec un capteur d'emplacement de document (38) ;

    (d) surveiller un profil de vitesse de la trajectoire de transport de document ;

    (e) contrôler la vitesse du moteur ; et

    (f) réduire la vitesse du moteur pour compenser les changements attendus de vitesse du document le long de la trajectoire de document, transportant ainsi le document à une vitesse plus constante le long de la trajectoire de transport de document,

    dans lequel le transport du document avec un système de rouleau (16, 18, 20, 24, 26) comprend l'étape pour pousser le document dans la trajectoire de transport de document avec un rouleau de poussée (16) et séparer des feuilles individuelles de documents avec un dispositif de séparation (21),
    dans lequel la détection d'un bord du document comprend la détection d'un bord de fuite du document ;
    dans lequel la vitesse du moteur est réduite au moment où un bord de fuite du document est libéré d'une ligne de pincement du dispositif de séparation (21) afin de compenser un changement attendu de vitesse du document dû à la libération de la ligne de pincement du dispositif de séparation (21),
    dans lequel le rouleau de poussée (16) a un capteur de rouleau de poussée (42) détectant le bord de fuite du document en détectant un arrêt dans une rotation du rouleau de poussée (16), et
    dans lequel le moment où l'on réduit la vitesse du moteur est calculé en utilisant le bord de fuite détecté du document, la distance allant d'une ligne de pincement du rouleau de poussée (16) jusqu'à une ligne de pincement du dispositif de séparation (21), et une vitesse de transport programmée.
     
    9. Méthode selon la revendication 8, dans laquelle la détection d'un bord du document comprend la détection d'un bord d'attaque du document.
     
    10. Méthode selon la revendication 8, comprenant en outre la surveillance des profils de vitesse des précédents passages des autres documents le long de la trajectoire de transport de document.
     
    11. Méthode selon la revendication 8, comprenant en outre la modification de la vitesse du moteur pour compenser les changements attendus de vitesse du document le long de la trajectoire de document basée sur les profils de vitesse des précédents passages des autres documents le long de la trajectoire de transport de document.
     
    12. Méthode selon la revendication 9, comprenant en outre la modification de la vitesse du moteur après la détection du bord d'attaque du document.
     
    13. Méthode selon la revendication 8, comprenant en outre la modification de la vitesse du moteur après la détection du bord de fuite du document.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description