Abstract:
The present invention relates to a system for providing diagnostic information relating to the performance of an inserter system having a roller arrangement for conveying a document in a linear direction and first and second sensors located in close proximity to the roller arrangement. Each of the sensors are operable to detect at least the presence of a leading edge of a document conveying in close proximity to each sensor. The control system of the inserter determines the time it takes for a leading edge of a document to convey from said first sensor to said second sensor and compares that time to a prescribed threshold time and provides diagnostic information based upon the measured times values.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to the field of inserting machines. More particularly, the present invention pertains to monitoring the motion of sheets through a sheet handling device, such as a mailing or high-speed inserter to provide machine control diagnostics. 
     BACKGROUND OF THE INVENTION 
     A typical sheet or envelope handling device includes various structures, motors and sensors. For example, a typical envelope handling device includes an envelope feeding structure for feeding an envelope or a batch of envelopes in singular fashion in a downstream path of travel to a work station. Typical envelope handling devices employ ejection rollers or ejection belts operating at a constant speed, or at some speed that varies as a function of time, speeds chosen so as to avoid envelope collisions and noise. It is beneficial to control to a fine degree the motion of a sheet or envelope handling device so as to keep noise and undesirable motion of the sheets or envelopes to a minimum. 
     The prior art uses motion profiles to express, as a function of time, the velocity/speed of an axis of a motor that causes motion of a sheet in a mailing system. A motion profile consists of a series of segments, each segment having a duration and each corresponding to a state of motion of an axis of a motor ultimately responsible for imparting motion to a sheet or envelope. 
     For example, a motor may have an axis that in rotating pulls a sheet through part of a mailing system at a certain speed, after accelerating at a specified acceleration as a function of time, and concluding with some specified deceleration as a function of time. If the sheet does not slip, then the motion of the sheet can be correlated precisely with the motion of the axis of the motor: the sheet moves through the mailing system with a speed that is exactly equal to the speed of rotation of the part of the axis in contact with the sheet, i.e. usually the surface of a belt driven by the axis. In this case, commands are sometimes sent to a motor to impart motion to a sheet, for a series of time segments, based simply on the assumption that the motion of the axis of the motor causing the motion of the sheet can be equated to the motion of the sheet. 
     On occasion, however, a sheet in a sheet handling device will slip so that the motion of the axis does not necessarily indicate the motion of a sheet (or envelope). Then the motion of an axis of a motor can be conditioned based on receiving commands from sensors used to detect the presence of the sheet as it moves through the sheet handling device. 
     Typically, and even in such complex sheet handling machines, the operation of these machines is often categorized as simply working or not working without regard for how well the machine is operating, or more importantly, how close it is to failing. Hence there is a need to determine degraded performance in sheet handling machines and to predict likely failure of such a machine for the purpose of proactively adjusting and/or servicing the machine prior to experiencing machine failure. In the prior art, the diagnosis of sheet handling machine control problems was achieved through a combination of inferred cause and effect complied from the theory of how the sheet handling machine was supposed to operate. This prior art method is both imprecise and burdensome as machine problems were often identified after experience of a malfunction often causing damage to the documents being process in the sheet handling machine. 
     Therefore, it is an object of the present invention to provide a diagnostic methodology for sheet handling machines to continuously monitor and evaluate the operation of sheet handling machines during their operation and interpret collected data in real time to provide diagnostic information indicating as to how the machine is operating. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention relates to a system for providing diagnostic information relating to the performance of an inserter system based upon data collected from documents conveying within the inserter system. 
     Preferably, it is the control system of the inserter system that is utilized to provide the diagnostic information. In use, the control system is preferably coupled to a roller arrangement in the inserter system utilized for conveying a document in a linear direction, with the control system being further coupled to first and second sensors located in close proximity to the roller arrangement. Each of the sensors are operable to detect at least the presence of a leading edge of a document conveying in close proximity to each sensor. The control system of the inserter determines the number of encoder counts (e.g., incremental rotational movements of a motor in the roller arrangement) it takes for a leading edge of a document to convey from said first sensor to said second sensor and compares the measured encoder counts to a prescribed number of encoder counts and provides diagnostic information based upon this comparison. In the event the diagnostic information reveals poor performance or possible malfunction is to occur in the inserter system, appropriate warning indicators are then provided to an operator of the inserter system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects and advantages of the present invention will become more readily apparent upon consideration of the following detailed description, taken in conjunction with accompanying drawings, in which like reference characters refer to like parts throughout the drawings and in which: 
     FIG. 1 depicts a block diagram of an inserter system that is the operating environment for the preferred embodiment of the present invention; 
     FIG. 2 is a simplified roller arrangement implementing the present invention diagnostic control system; 
     FIG. 3 is a flow chart depicting the diagnostic method of the present invention; and 
     FIGS. 4A,  4 B and  4 C are diagnostic charts provided by the method of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In describing the preferred embodiment of the present invention, reference is made to the drawings, wherein there is seen in FIG. 1 a schematic of a typical document inserting system, generally designated  10 , which implements the present invention input system  100 . In the following description, numerous paper handling stations implemented in inserter system  10  are set forth to provide a thorough understanding of the operating environment of the present invention. However it will become apparent to one skilled in the art that the present invention may be practiced without the specific details in regards to each of these paper-handling stations. 
     As will be described in greater detail below system  10  preferably includes an input system  12  that feeds paper sheets from a paper web to an accumulating station that accumulates the sheets of paper in collation packets. Preferably, only a single sheet of a collation is coded (the control document), which coded information enables the control system  100  of inserter system  10  to control the processing of documents in the various stations of the mass mailing inserter system. The code can comprise a bar code, UPC code or the like. 
     Essentially, input system  12  feeds sheets in a paper path, as indicated by arrow “a,” along what is commonly termed the “main deck” of inserter system  10 . After sheets are accumulated into collations by input system  12 , the collations are folded in folding station  14  and the folded collations are then conveyed to a transport station  16 , preferably operative to perform buffering operations for maintaining a proper timing scheme for the processing of documents in inserting system  10 . 
     Each sheet collation is fed from transport station  16  to insert feeder station  18 . It is to be appreciated that a typical inserter system  10  includes a plurality of feeder stations, but for clarity of illustration only a single insert feeder  18  is shown. Insert feeder station  18  is operational to convey an insert (e.g., an advertisement) from a supply tray to the main deck of inserter system  10  so as to be nested with the aforesaid sheet collation being conveyed along the main deck. The sheet collation, along with the nested insert(s) are next conveyed into an envelope insertion station  20  that is operative to insert the collation into an envelope. The envelope is then preferably conveyed to a postage station  22  that applies appropriate postage thereto. Finally, the envelope is preferably conveyed to a sorting station  24  that sorts the envelopes in accordance with postal discount requirements. 
     It is to be appreciated that the depicted embodiment of inserter system  10  implementing the present invention control system  100  is only to be understood as an example configuration of such an inserter system  10 . It is of course to be understood that such an inserter system may have many other configurations in accordance with a specific user&#39;s needs. 
     As previously mentioned, inserter system  10  includes a control system  100  coupled to each aforesaid modular component of inserter system  10 , which control system  100  controls and harmonizes operation of the various modular components implemented in inserter system  10 . In accordance with the present invention, control system  100  is now adapted to preferably provide diagnostic information for each various modular component of inserter system  10 . Specifically, and as will be described below, control system  100  continuously monitors and evaluates the operation of one or more modular components of an inserter system  10  during their operation and interprets collected data in real time to provide a machine operator with data as to how the inserter system  10  is operating as well as provide warning indications when appropriate. 
     With reference now to FIG. 2, there is shown a typical roller arrangement, designated generally at  200 , which is operable to convey a document  220  along the direction of travel indicated by arrow “B” in any one of the aforesaid modular components of inserter system  10 . Roller arrangement includes a drive roller  202  and an associated driven roller  204 . Connected to drive roller  202  is preferably a servo motor  206 , which is coupled to control system  100 . As is well known, servo motor  206  causes the incremental rotation of drive roller  202  (along the direction of arrow “C”) wherein each incremental rotation corresponds to an encoder pulse of stepper motor  206 . In the present invention, each encoder pulse of stepper motor  206  is monitored by control system  100 . It is also to be appreciated that the present invention is not to be understood to be limited to use of servo motors  206 , but rather may be utilized with any type of motor that has an encoder feed (e.g., stepper motors) or a motor coupled to a position encoder that similarly corresponds incremental rotation of the motor into encoder counts, which encoder counts are monitored by control system  100 . 
     Roller arrangement  200  further preferably includes first and second sensors  208 ,  210 , which sensors are preferably optical sensors for detecting the passage of a document in proximity to the sensor. Sensors  208  and  210  are not to be limited to optical sensors but rather may encompass any type of sensor capable of detecting passage of a document. Each sensor  208  and  210  is coupled to control system  100  to provide feedback to control system  100 . 
     It is further to be appreciated that this exemplary roller arrangement  200  may be implemented in any portion, or modular component of an inserter system  10  in which a document conveys between two fixed reference points (e.g., sensors  208  and  210 ). And, the present invention may be used to monitor a specific portion of an inserter system  10  (e.g., a sheet feeder) or may be used to simultaneously monitor a plurality of different portions of an inserter system  10 , wherein each portion of the inserter system  10  would have a similar type of roller arrangement  200  coupled to the control system  100  of the inserter system  10 . 
     Turning now to the flowchart of FIG. 3, the operation and methodology of the present invention will now be described. First, a predetermined reference threshold value (DT) is established for the number of encoder counts it takes a leading edge  222  of a document  220  to convey from the first sensor  208  to the second sensor  210 . In accordance with the preferred embodiment of the present invention, DT=DN+DS, where DN is the expected encoder count it takes for the leading edge  222  of a document  220  to convey from the first sensor  208  to the second sensor  210  (as indicated by the distance “E”) and DS is a value (in encoder counts) to allow for material slippage which may be experienced by the document  220  as it&#39;s leading edge  222  conveys from the first sensor  208  to the second sensor  210 . 
     In use, preferably once operation of the inserter system  10  starts (step  400 ), the control system  100  retrieves the predetermined value for the aforesaid threshold value (DT) (step  402 ), which may be adjusted from time to time by a user depending upon the operating parameters required for a specific job task to be performed by the inserter system  10 . First, a determination is made as to whether the first sensor  208  detects a leading edge  222  of a document (step  404 ). If yes, the control system  100  counts the number of encoder pulses corresponding to rotation of drive roller  222  once the leading edge  222  of the document  220  conveys past the first sensor  208  (DC) (step  406 ). A determination is then made as to whether the encoder count (DC) exceeds the threshold value (DT) prior to the second sensor  210  detecting the lead edge  222  of the document  220  (step  408 ). If yes, then the control system  100  preferably causes a signal to be conveyed to an operator (step  410 ) and preferably causes stoppage of the inserter system  10  to prevent damage occurring to the inserter system  10  and/or documents being processed in the inserter system  10 . This is because the document  220  is taking too much time conveying between the first and second sensors  208 ,  210  (as the threshold value (DT) as already been exceeded) indicating a malfunction condition is present in the inserter system  10  requiring operator attention. 
     If the encoder count (DC) does not exceed the threshold value (DT) a determination is then made as to whether the second sensor  210  has detected the leading edge  222  of a document  220  (step  412 ). If no, the encoder count (DC) is continued (step  406 ) and the above process therefrom is repeated. If yes, meaning the second sensor  210  detects the leading edge  222  of a document  220  before the encoder count (DC) exceeds the threshold value (DT), the control system  100  then categorizes the document  220  has arrived at the second sensor  210  within a permitted time period (e.g., less than DT) and the encoder count (DC) is stop and stored as a saved encoder code (DA) for further processing as described below (step  414 ). 
     Next, the latest recorded encoder count (DA) and all previous generated encoder counts are processed by the control system  100  for providing diagnostic information regarding the inserter system  10  (step  416 ). It is to be appreciated that various types of data processing may be performed regarding the aforesaid stored encoder counts, including, but not limited to, computing the: Mode, Average and Standard Deviation for the stored encoder counts. It is to be appreciated that the aforesaid processing for the stored encoder counts may be configured in various formats, such as comparing the Mode (the most frequently occurring encoder count (DA) value) to the expected encoder count time (DN). And, should the difference in these compared values be more than a predetermined amount (e.g., 10 encoder counts) (step  418 ), a warning message is caused to be conveyed from the control system  100  to an operator of the inserter system  10  indicating that actual (e.g., real time) operation has deviated significantly from the nominal indicating a potential problem in relevant portion of the inserter system  10  being monitored (step  420 ) while continuing to permit the inserter system to operate. 
     For example, and with reference now to FIGS. 4A,  4 B and  4 C, graphs are shown depicting exemplary distributions for stored encoder counts (DA). In regards to the exemplary illustrations of FIGS. 3A,  3 B and  3 C, the expected encoder value (DN) is  100  counts with threshold encoder warning values being prescribed at +/−10 encoder counts and having upper and lower threshold value limits (DT) being prescribed at +/−20 encoder counts. Therefore, warnings are generated when the mode of distribution exceeds +/−10 encoder counts, and in instances when an encoder count (DA) exceeds the threshold value (DT) (e.g., +/−20 encoder counts), the inserter system  10  is preferably caused to immediately stop via the control system  100 . 
     With specific reference to FIG. 4A, there is shown a diagnostic chart depicting the operation of an inserter system operating in a good condition wherein the majority of the sampled encoder counts (DA) are clustered around the nominal threshold value (DN). FIG. 4B illustrates a diagnostic chart depicting operation of an inserter system that while it may be operating correctly, it is not within optimal performance since the difference between the Mode value for the encoder counts (DA) and the nominal threshold value (DN) is an indication of the performance of the inserter system  10 , or at least the component of the inserter system  10  that is being monitored. Referring now to FIG. 4C, there is illustrated a diagnostic chart depicting operation of an inserter system  10  operating out of specification, whereby while it is still permitted to function (the threshold value (DT) has not yet been exceeded), it is functioning in a degraded mode since the Mode value for the encoder counts (DA) is greater than the aforesaid upper threshold value (e.g., 110 encoder counts) and a warning message is caused to be generated by the control system  100  to an operator indicating that the inserter system  10 , or a specific component of the inserter system  10  requires attention. 
     It is to be particularly appreciated that the present invention diagnostic system made be used for many machine events occurring in an inserter system  10  so that it simultaneously monitors each event, while the inserter system  10  is operating, thus all areas of an inserter system  10  may be monitored simultaneously with warnings be provided when a particular inserter component is operating outside of the aforesaid threshold values. Additionally, an inserter system operator may selectively choose a diagnostic chart for a selected component of the inserter system  10  to view its current operating performance state. Further, while the preferred embodiment of the invention makes reference to tracking document movements by it&#39;s arrival at sensor  208  and  210 , the present invention may make reference to tracking document movement by: document length (the lead edge  222  is detected by a first sensor  208  compared to the trail edge as detected by the second sensor  210 ); gap between documents  220  (e.g., trail edge of document  220  detected by the first sensor  208  and the lead edge of the next document is detected by the same first sensor  208 ; and arrival skew/departure skew (e.g., two sensors are mounted perpendicular to the direction of the normal document path such that by comparing the normal detection of the lead and trailing edges of a document, the skew of the material can be computed. 
     It is further to be appreciated that the present invention diagnostic system and method is not to be understood to be limited to use on an inserter system but may be used on type of device wherein there is real time comparisons between actual and expected operation, such as, voltage of power supplies (e.g., average voltage over time), pressure (e.g., average air-line pressure), temperature (average temperature), etc. 
     In summary, a method for providing diagnostic control of an inserter system has been described. Although the present invention has been described with emphasis on a particular embodiment, it should be understood that many changes and modifications may be made to the invention without departing from the scope and spirit of the invention as disclosed. For example, many modifications and adaptations to the preferred embodiment will be apparent to those skilled in the art. Further, those skilled in the art will appreciate that some aspects of the present invention will be used to advantage without the corresponding use of other aspects. 
     Accordingly, the foregoing description of the preferred embodiment should be considered as merely illustrative of the present invention and not in limitation thereof.