Automatic feeder control system to account for input variations

Abstract

 The present application relates generally to a method and system for the processing of mail items (102) within a document processing system. More specifically, described herein is a method and system for automatically adjusting the feeding of mail items (102) based on a stack pressure for minimizing jams and improving the overall system efficiency. Stack pressure is monitored as mail items (102) are fed to a transport path (106) and mail item feeding behavior is adjusted according to the stack pressure to minimize the mail item jams.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 61/052,722, filed May 13, 2008, which is incorporated by reference in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to a method and system for processing mail items within a document processing system.

BACKGROUND

[0003] Document processing facilities often use high speed document processing machines such as sorters, to sort and direct mail items appropriately to one or more mail bins for distribution. The efficiency of a sorter is generally dependent upon various factors, one of which is the rate at which mail items can be fed as input into the sorter's transport path by a feeder system. Typical feeder systems employ one or more motor driven belts in combination with a set of picker fingers, advance paddles or other means to progressively advance a plurality of mail items into the transport path. The more expedient the input of the mail items, the more expeditiously the sorter can process these mail items as they are guided downstream, through the sorter, along the transport path.

[0004] Consequently, jams that occur within the feeder system negatively impact sorter throughput and efficiency. As mail items placed into the feeder system vary in width due to variations in mail item content and width, air gap between mail items, etc., the stack pressure of mail items may also vary accordingly. Stack pressure refers to the relative pressure buildup resulting from a dense plurality of mail items to be input singularly into the transport path. The higher the stack pressure, generally resulting from the concentration of too many mail items attempting to be fed to a single point of entry to the transport path, the higher the likelihood of mail jams at the point of entry. Therefore, it is desired to monitor the stack pressure as the mail items are fed to the transport path and to adjust the mail feeding behavior according to the stack pressure to minimize the mail jams.

SUMMARY

[0005] One aspect of the present application includes providing a method for adjusting a mail feeding system. The method includes advancing a plurality of mail items in a first direction toward a guide mechanism. The guide mechanism is configured to guide the plurality of mail items to a transport path. The guide mechanism has a variable angular displacement indicative of a stack pressure against the guide mechanism. The variable angular displacement of the guide mechanism is compared with a pre-determined angular displacement. The stack pressure is adjusted in response to the comparison by advancing one or more of the plurality of mail items in a second direction opposite to the first direction.

[0006] Another aspect includes providing for a method for guiding a plurality of mail items to a transport path from a magazine of a document processing device. The method includes advancing a first mail item and a second mail item in a first direction towards a guide mechanism. The guide mechanism is configured to guide the first and the second mail items to a transport path. Prior to entry to the transport path, a gap between the first mail item and the second mail item is monitored. The guide mechanism is adjusted from a first to a second feed rate in response to the gap between the first mail item and the second mail item; and profile data associated with the first and second mail item. The second mail item is fed at the second feed rate onto the transport path based on the adjusting step.

[0007] Yet another aspect includes providing a feeder system. The system includes a variable speed magazine for driving a plurality of mail items in a direction toward or away from a transport path of a sorter. A guide mechanism guides each of the plurality of mail items onto the transport path. One or more guide mechanism sensors are included for continuously measuring a variable angular displacement indicative of a stack pressure against the guide mechanism. One or more gripper belts associated with the guide mechanism are capable of being driven in at least two speeds. The gripper belts suitably contact at least one of the plurality of mail items as it is driven by the magazine. One or more sensors are provided for monitoring a distance between successive mail items fed onto the transport path by said guide mechanism. A feeder control system is included for maintaining a consistent rate at which mail items are guided from the magazine onto the transport path by the guide mechanism. In response to an indicated stack pressure, the feeder control system drives the magazine in the direction toward or away from the transport path. In response to the monitored distance, the feeder control system adjusts the speed of the gripper belts.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawing figures depict concepts by way of example, not by way of limitations. In the figures, like reference numerals refer to the same or similar elements. In the figures, like reference numerals refer to the same or similar elements.

[0009] FIG. 1 depicts an exemplary feeder system for advancing mail items to point of entry to a transport path of a document processing device.

[0010] FIG. 2 depicts an exemplary guide mechanism of the feeder system for detecting the buildup of stack pressure near the point or entry.

[0011] FIG. 3(a) depicts a flow chart for adjusting a feeder system based on stack pressure on the guide mechanism as shown in FIG. 2.

[0012] FIG. 3(b) depict a flow chart guiding mail items to a transport path in feeder system of FIG. 1.

[0013] FIG. 4 illustrates a network or host computer platform, as may typically be used to implement a server.

[0014] FIG. 5 depicts a computer with user interface elements.

DETAILED DESCRIPTION

[0015] Described herein is a system and method for guiding mail items to a transport path, wherein the stack pressure is monitored at the entry to the transport path and the mail feeding behavior is adjusted based on the stack pressure.

[0016] As used herein, a "mail item" refers to any article having human or machine readable content generated thereon, and particularly that intended for delivery to a given recipient. Mail items may include, but are not limited to, envelopes, newsletters, newspapers, magazines, post cards, parcels or packages of varying thicknesses (e.g., flat mail), coupon booklets, brochures, and other like documents. Such documents may or may not be generated for the purpose of being distributed via an outgoing distribution channel (e.g., delivery company, postal authority), but rather, may be generated for direct/personal carry, private delivery, or internal distribution.

[0017] Also, as used herein, the phrase "document or mail processing system" refers to any high speed transport device(s) capable of processing mail items at considerably high rates with considerably high precision. Document processing systems may include, but are not limited to, inbound sorting equipment, outbound mail sorting equipment, and even various forms of inserter machines, mail integrity systems, or the like for office, commercial, or industrial settings. While the following discussion will present the teachings in an exemplary fashion with respect to a sorter device, it will be apparent to those skilled in the art that the teachings may apply to any type of document processing device requiring mail item input, and specifically, any system desiring or requiring means for dynamically compensating for excessive mail item density or gap variations occurring during input.

[0018] FIG. 1 depicts an exemplary feeder system 100 for advancing a stack of mail items 102 to a guide mechanism 200 at an entry point 104 of a transport path 106 of a sorter device. Typically, feeder systems 100 comprise the front end portion of a sorting device, employing various physical elements (e.g., drive belts, rollers, and pulleys) for receiving mail items as input and readying said mail items for processing by the other components of the sorter as it traverses the transport path 106. In the context of the examples presented herein, the feeder system 100 may also comprise various control devices (e.g., motors, sensors, programmable controllers) that operate independently or interdependently to effectively handle mail items. All of these devices may or may not be under the control of a central feeder control mechanism 170, which coordinates and tracks the actions of said devices within the feeder 100. Generally speaking, the various actions, tolerances and thresholds expected to be maintained or achieved by the devices can be defined as profile data. Examplary profile data, as provided to the feeder control system 170 in advance of a particular job run, may include but is not limited to: magazine belt speed data, stack pressure sensor threshold requirement data, variable gripper belt speed data, sensor status data, job characteristic data (e.g., mail item dimensions), etc., all data which may vary by client or job being processed.

[0019] The feeder control system 170 may further be integrated or communicable with a sorter control computer configured for interaction with the sorter. Regardless of configuration, one skilled in the art will recognize that various means of facilitating electro-mechanical control within a dynamic system exist, and that any control configuration is within the scope of the teachings described herein.

[0020] The stack of mail items 102 is placed into the feeder system 100 in an upright position such that the face of each mail item is exposed as it is transported down the transport path 106 at a given transport speed (e.g., as measured in inches per second (IPS)). For the purposes of the discussion herein, the face of a mail item within a stack thereof is to be taken synonymously as the stack plane, i.e., the two-dimensional plane that is advanced in the direction of the entry point to enable a leading edge of the mail item to enter the transport path 106 via the point of entry 104. Of course, those skilled in the art will recognize upon full discussion of the exemplary embodiment herein that other orientations of mail items are within the scope of the teachings as well.

[0021] Once entered onto the transport path 106, each mail item may be processed by various inline modules, such as imaging devices, printers, barcode readers, etc. (not shown). Such mail items typically being processed by these modules in response to one or more delivery point identifiers (e.g., ZIP Code designations) or address components (e.g., address block data) as marked thereon. The stack of mail items 102 advance down the base 108 of a magazine 107 of the feeder system 100 towards a point of entry 104 of the sorter transport path 106 with the aid of a stack plate 110, wherein the stack plate 110 is able to traverse the length of the magazine 107 in the direction X or Y as shown. The stack plate 110 of the magazine 107 is driven by a synchronized pair of motor driven belts 120 and 122, each belt containing grooves for affixing the bottom edge of the stack plate 110 and the bottom edge of the mail stack 102. As belts 120 and 122 of the magazine 107 are driven by the belt motor 130 at a fixed or variable velocity in either direction X or Y, the stack plate 110 accordingly retracts or advances the mail items 102 at a respective rate. A presence detector 155 may be used to detect the presence of mail items 102 during advancement.

[0022] The stack may be in a fixed position between the stack plate 110 and one of the grooves within the belts 120 and 122, resulting in a fixed stack pressure, i.e., a rigid contraction or density to be maintained as the stack advances toward the entry point 104 (in direction Y) of the transport path 106. Alternatively, the grooves within drive belts 120 and 122 may become level with the plane of the feeder base 108 at a release point 150, wherein the stack plate 110 advances the mail items without further reliance upon grooves on belts 120 and 122. This configuration in turn results in repositioning of mail stack 102, i.e., loosening or expansion, so that the stack pressure is subsequently minimized while still maintaining relative upright orientation with respect to the entry point 104 and transport path 106. Those skilled in the art will recognize that such variation from a rigid or fixed stack pressure to a more relaxed stack pressure proximate to actual entry to the transport path 106 further reduces the accumulation of excess stack pressure at the point of entry 104.

[0023] To enable an individual mail item within the mail stack 102 to be processed by the sorter, each item must be sufficiently separated or pulled from the stack to enable only one item at a time to be conveyed to the transport path 106 through the point of entry 104. One or more stripper fingers, suction devices and/or other combinations of elements capable of exerting restrictive, pulling or complimentary counter force may be used to single out (i.e., singulate) and separate individual mail items from stack 102 for entering to the transport path 106. In conjunction with a singulator means 210, a guide mechanism 200 as illustrated by way of example in FIG. 2 may provide a complimentary force to advance the leading edge 160 of a mail item in the direction of the transport path 106 upon contact with a mail item, thereby minimizing the accumulation of excessive mail items proximate to the point of entry 104. As will be seen, increased density of mail items at the point of entry 104, referred to herein as a stack pressure, may cause jams, considerable gaps between successive mail items (e.g., doubles) or other processing defects that affect the sorter's efficiency and processing capability.

[0024] According to one embodiment as shown in FIG. 2, the guide mechanism 200 acts as a physical buffer that prevents the overrun of mail beyond the extent of the belt drives 120 and 122 and/or positions the mail item or stack in proximity to the point of entry 104. Furthermore, the guide mechanism 200 is coordinated to generate a frictional force complimentary to any static force exerted by the singulator 210 to advance mail items at the point of entry 104 toward the transport path 106. As will be discussed in further detail, said frictional force is provided via a plurality of variable speed, motor-driven friction belts capable of driving mail items upon contact. Still further, the behavior of the guide mechanism 200 in response to contact with mail items as they are advanced towards the point of entry 104, as detected by presence sensor 155, further triggers varying behaviors of the overall feeder system 100. The guide mechanism 200 is affixed about a vertical pivot axis Z (i.e., a drive shaft) to a guide motor drive 202 positioned below the feeder base 108. In one embodiment, the motor drives 202 and 130 are independently controlled by different motor controllers, such that the guide motor drive 202 operates independently of the belt motor 130 that drives belts 120 and 122, resulting in asynchronous operations of respective motors 202 and 130. Consequently, the motor drive 202 of the guide mechanism 200 may drive its gripper belts 206 at one speed (e.g., as inches per second (IPS) 208), while belts 120 and 122 may be driven at a different speed. Alternatively, both motor drives 130 and 202 may be coupled to a twin axis motion controller 204, wherein the motors 130 and 202 can be synchronized or adjusted with respect to each other at the discretion of the controller 204.

[0025] The gripper belts 206, when rotated in the direction shown in FIG. 2, exert a frictional force upon contact with the face of a mail item proximate to the point of entry 104. The frictional force, resulting from the rotational velocity of the gripper belts 206 in accord with a variable speed guide motor controller 202 or the like, is exerted onto the mail item in the direction of the transport path 106. As stated, a complimentary static counter force is exerted by the singulator 210 upon the mail stack 102 at the point of entry 104 to ensure that a single mail item is stripped from the stack 102 and advanced towards the transport path 106. According to the exemplary embodiment described herein, the guide mechanism 200 varies its rotational position (i.e. the angular displacement), as it comes in contact with the mail stack 102, in a range including a rest position 214, a drive position 216 and a reverse position 218. Each angular displacement affects the behavior of the feeder system as described hereafter. Skilled artisans will recognize that future implementations of the examples presented herein may involve displacement of a linear nature versus rotational.

[0026] As depicted in FIG. 2, prior to contact with the mail stack 102, the guide mechanism 200 maintains a natural rest position 214 corresponding to an angle of 0 degrees (or alternatively, may be perceived as corresponding to a value less than zero). As the mail stack 102 is advanced toward the guide mechanism 200, it is detected by the presence sensor 155 and eventually begins to contact the guide mechanism 200. Consequently, the angular displacement about the pivotal axis Z also steadily increases, and eventually to an angle of α degrees wherein the stack plane 272 is approximately parallel to the drive position 216. This causes the face of the foremost mail item within the stack to substantially come into contact with drive belts 206 in a manner suitable for advancing the leading edge of the mail item to the transport path 106 through a parallel plane contact. This is further depicted via inset 270 of FIG. 2, where a two dimensional top view of the guide mechanism 200 is shown, illustrating the general orientation of the stack plane 272 (i.e., the frontal face of the mail item) relative to the guide mechanism 200 at rest position 214. It will be understood by one skilled in the art that the contact plane of the guide mechanism 200 is not generally parallel to the stack plane 272 until the guide mechanism is offset or rotated α degrees to the drive position 216. Consequently, the guide motor drive 202 remains inactive for any angular displacement of the guide mechanism 200 less than α degrees.

[0027] When the angular displacement of the guide mechanism 200 is greater than or equal to α degrees and the presence detector 155 determines the presence of mail items proximate to the point of entry 104, the guide motor drive 202 is activated. Prior to these conditions being met, the gripper belts 206 need not be active while the stack is steadily advancing forward. Hence, the contact plane of the guide mechanism at this point and the drive portion of the gripper belts 206 become parallel to the stack plane 272, thereby enabling a substantial frictional force to be applied onto the mail item at the point of entry 104 versus the static counter force of the singulator 210. From this point on, the belts 206 and the guide motor drive 202 remain active as the guide mechanism 200 is further rotated due to an increase in the stack pressure proximate to the point of entry 104.

[0028] The angular displacement 218 of θ degrees represents the maximum allowable rotational movement of the guide mechanism 200 beyond its rest position 214 before further adaptation of feeder system 100 is required. Rotation beyond the angular displacement 218 is limited due to the restriction of an extension arm 222 of the guide mechanism 200 by a buffer 224. The extension arm 222 is connected to a spring 226 that exerts a tensional force suitable for enabling controlled rotational movement and return of the guide mechanism to its rest position 214. As further depicted in FIG. 2, a magnet 232 is disposed at one end of the extension arm 222 at a small distance above a magnetic field variance sensor 230. The magnetic field variance sensor 230, also known commonly as a Hall Effect sensor, is a transducer that varies its output voltage in response to changes in the magnetic field intensity as the magnet 232 is rotated in accordance with the guide mechanism 200. Hence, as the position of the magnet 232 changes due to rotation of the guide mechanism 200 to an angle ranging from α degrees and θ' degrees, where θ' may be equal to or slightly greater than θ depending on the configuration of the extension arm 222, so too does the magnetic field intensity.

[0029] Upon detecting that the magnetic field intensity has diminished with respect to a position of the magnet 232 corresponding to an angle greater than θ degrees (e.g., an angular displacement beyond the reverse position 218 of the guide mechanism 200 up to θ' due to the accumulated density of mail items), the sensor 230 generates a signal to the feeder control system 170 indicating an excessive stack pressure condition resulting from an accumulation of mail items near the guide mechanism 200. To account for this, the feeder control system 170 responds by reversing the forward advancing direction Y of the belt motor drive 130 and hence belts 120 and 122, thereby reversing the direction of advancement 212 of the mail stack and reducing the stack pressure. This allows the guide mechanism 200 to retract in a controlled manner towards its natural rest position 214 as the force exerted upon it in direction 212 by the mail stack 102 is subsequently decreased. Alternatively, rather than reverse the drive direction of belts 120 and 122, the feeder system 100 may ramp down the speed of the belt motor 130 controlling belts 120 and 122, said speed being adjusted in proportion to the extent of angular displacement of the guide mechanism 200 as detected by the magnetic field variance sensor 230. Once positioned again between the drive position 216 and the reverse position 218, the belts 120 and 122 may resume their drive in direction 212 (i.e., direction Y as depicted in FIG. 1).

[0030] The twin axis motion controller 204 may be employed as a means for coordinating the control action of drive belts 120 and 122 in response to a given stimulus. Specifically, as the angular displacement of the guide mechanism 200 increases from drive position 216 to reverse position 218 due to build up of the stack pressure; such variation is continuously monitored by the sensor 230. The sensor 230 generates and transmits a signal to the feeder control system 170, indicating the extent of motion of the guide mechanism 200. In responding to the received signal, the feeder control system 170 generates a control signal for adjusting the behavior of the feeder system 100. For example, the feeder control system 170 may continuously or in a stepwise fashion reduce the speed of stack advancement in direction Y in response to the signal, thereby reducing the stack in proximity to the point of entry 104 and the guide mechanism 200.

[0031] As another example, the feeder control system 170 may increase the rotational speed (i.e., IPS 208) of motor drive 202 of the guide mechanism 200 in response to the signal, thereby increasing the speed of the drive belts 206 and the rate of feeding the mail items into the transport path 106. As the speed of removing the mail items from the mail stack 102 is increased, the stack pressure exerted onto the guide mechanism 200 is gradually reduced.

[0032] According to another embodiment, a touch sensor may be disposed on the side surface of buffer 224 for detecting the excessive stack pressure. Specifically, as the guide mechanism 200 is rotated to the position corresponding to the angle of θ' degrees due to the excessive stack pressure, the extension arm 222 comes into contact with the side surface of the buffer 224, thereby triggering the touch sensor to generate a signal indicating that the stack pressure exerted onto the guide mechanism 200 has exceed a safety limit (i.e. a threshold). In receiving the signal, the feeder control system 170 may adjust the behaviors of the feeder system 200. For example, the feeder control system 170 may reverse the direction of stack advancement, stop or ramp down the speed of the belt motor 130 with respect to the extent of angular displacement of the guide mechanism 200 or deactivate guide motor drive 202 responsive to reduced angular displacement of the guide mechanism 200 resulting from reversing of belt motor 130-i.e., when displacement is less than drive position 216,.

[0033] As another alternative embodiment, a pressure sensor may be disposed on the side surface of buffer 224 for monitoring the stack pressure exerted onto the guide mechanism 200. Specifically, as the guide mechanism 200 is rotated to the position corresponding to the angle of θ' degrees due to the accumulation of the mail items in front of the entry point 104, the extension arm 222 comes into contact with the side surface of the buffer 224, thereby exerting pressure onto the pressure sensor. As the mail items accumulate and the stack pressure continuously increases so does the pressure exerted onto the pressure sensor by the extension arm. At the same time, the pressure sensor generates and transmits a signal to the feeder control system 170 indicating the pressure detected by the pressure sensor at the contact point between the buffer 224 and the extension arm 222. Upon determining that the detected pressure indicated by the signal exceeds a pre-determined threshold, the feeder control system 170 adjusts the behaviors of the feeder system 100 as described earlier in this application. In addition, the pre-determined threshold may be adjusted by a user for setting the maximum allowable stack pressure exerted onto the guide mechanism 200 before the feeder control system 170 starts to execute the adjustment.

[0034] Regardless of the chosen approach, skilled artisans will recognize that modifying the behavior of the feeder system 100 in response to the degree of positional displacement of the guide mechanism 200 provides a means of compensatory feedback to thwart common feeding problems. Furthermore, it will be recognized by those skilled in the art that measuring pressure may be performed using a pressure transducer, force control monitoring device or other pressure detection means other than as a function of an extent of displacement. In this way, the sensor output produced by such pressure detection means would be suitable for indicating pressure exertion near the point of entry to the transport path and could directly replace a measurement of angular displacement as an indicator of stack pressure variation. Still further, as the behavior of the feeder system varies depending on the positional displacement, the range or threshold of displacement may be tempered to the requirements of a given sorter system accordingly. For example, while the generalized behavior of the feeder system 100 in response to varying stack pressure conditions as described above is indicated in TABLE 1 below, skilled practitioners may adjust the extent of α or θ, the speed of the belt motor drive 130, the proportional control settings of the twin axis motor controllers with respect to motor drives 130 and 202, etc, and other profile data.

TABLE 1: Response of feeder system to varying stack pressure conditions

Position; Displacement	Belts 120 and 122	Gripper Belts 206
Upon start-up and between rest position 214 and drive position 216; 0 to α degrees	Active; driven in direction 212 at a variable speed, proportional to extent of θ	Inactive
Beyond drive position 216 up to reverse position 218; Greater than α up to θ degrees	Active; driven in direction 212 at a decreasing variable speed, proportional to extent of θ	Active
Beyond reverse position 218; Greater than 0 degrees	Active; driven in reverse at an increasing variable speed, proportional to extent of θ	Active

[0035] As depicted in the table, when the guide mechanism is positioned between rest position 214 up to a pre-determined angular displacement (i.e., drive position 216), the feeder control system 170 enables belts 120/122 to drive toward the point of entry 104 at a proportionally decreasing speed; hence regulating the rate of stack pressure accumulation near the point of entry 104. Also, as depicted, when the guide mechanism is positioned well beyond the pre-determined angular displacement (i.e., greater than reverse position 218), the feeder control system 170 enables belts 120/122 to drive away from the point of entry 104 at a proportionally increasing speed; hence regulating the rate of stack pressure accumulation near the point of entry 104. Therefore, the speed and direction of the drive belts 120/122 is persistently regulated to maintain as consistent a rate of stack pressure for affecting the rate of mail item feeding within the feeder system 100. Of course, this dynamic regulatory behavior of the feeder system 100 will vary relative to differing profile variables (e.g., α, θ, the speed of the belt motor drive 130, job characteristics).

[0036] Once a mail item is singled out and forced by the guide mechanism 200 through the point of entry 104 in the direction of the transport path 106, one or more edge detection sensors 220a-b placed adjacent to the transport path 106 may detect the presence of a leading or lagging edge of a mail item as it moves towards the transport belt. Various sensor configurations may be employed accordingly, including those wherein the receiver and transmitter sensor components are integrated or separated by a given distance. Immediately following the first fed mail item, the next mail item is advanced such that a gap between the first mail item and the second mail item exists. Variations in gap between respective mail items may be persistently monitored via analysis of the data yielded by the edge detection sensors 220a-b. While some variation is typically expected when processing mail items having common dimensional characteristics (e.g., length) to within a threshold of variance, excessive or progressively increasing gap is usually a result of ineffective feeding by the feeder system. Progressively decreasing gap between mail items is usually an indicator of doubles being passed through the transport path. Lack of consistent gap, therefore affects the overall throughput and efficiency of the sorter device. Furthermore, lack of consistent gap may result from excessive stack pressure.

[0037] In responding to gap variations, and given known conditions that affect the gaps between consecutive mail items (e.g., distance between edge detection sensors, the speed 208 of the mail item in inches per second, expected mail item length or doubles resulting from improper mail item feeds), the feeder system 100 may alter its behavior to compensate for variations in gap-i.e., variation from a pre-set mail item gap length. For example, the feeder control system 170 may reduce or increase the speed of the guide mechanism motor drive 202 and hence the speed of the gripper belts 206. Furthermore, the feeder control system 170 may alter the function of motor drives 130 and 202 relative to each other with regard to a determined gap variance breach, etc., as a means of compensating for detected error conditions. Exemplary behavior of the feeding device responsive to the monitored gap between the first and second mail item is shown in the Table 2 below:

TABLE 2: Response of feeder system to varying gap conditions

Status of sensor 220(a)	Status of sensor 220(b)	Status of Gripper Belts 206
Not blocked by passing mail item (mail item not present)	Not blocked by passing mail item (mail item not present)	Active in high speed mode
Blocked by passing mail item (mail item is present)	Not blocked by passing mail item (mail item not present)	Active in high speed mode
Not blocked by passing mail item (mail item not present)	Blocked by passing mail item (mail item is present)	Active in high speed mode
Blocked by passing mail item (mail item is present)	Blocked by passing mail item (mail item is present)	Active in low speed mode

[0038] Of course the rate (as measured in IPS)-high speed or low speed-of the gripper belts 206 will vary depending upon the intended or desired gap length or pitch to be maintained or accounted for. For instance, at a gap length of 2-3" between mail items, a high speed mode may correspond to a rate of 160 IPS while a low speed mode is at a rate of 105 IPS. For a gap length of 4-5" between mail items, high speed mode may be 90 IPS while low speed is 50 IPS. Those skilled in the art will recognize that the progressive ramping up or down of the gripper belts 206 in response to detected gap or pitch variations enables more continuity and enhanced processing of mail items along the transport path 106. Mail items may be appropriately sped up (e.g., from 0 IPS and up) or slowed down (to 0 IPS) in response to monitored gap length and/or pitch, and with respect to a known speed of the transport path 106 itself, as a means of maintaining gap continuity upon entry to the transport path 106.

[0039] As a further means of maintaining gap or pitch continuity between successive mail items entered onto the transport path 106, the feeder control system 170 may dynamically switch between gap-based feeding and pitch-based feeding respective to a comparison between an actual monitored pitch and a specified minimum pitch. Specifically, when the actual measured pitch (length of a first mail item + gap length between the second mail item) is determined to be greater than a specified minimum pitch threshold (e.g., definable profile data), the guide mechanism 200 of feeder system 100 may operate as a gap-based feeder. When the actual measured pitch is determined to be less than the specified minimum pitch, a determination is made as to the extent of gap needed to meet the specified minimum pitch. Once determined, the the feeder control system 170 may adapt the guide motor drive 202 speed accordingly to accommodate, meet or maintain the fixed minimum pitch constraint.

[0040] According to one embodiment as depicted in FIG. 3(a), a method 300 is provided for adjusting a mail feeding system based on a stack pressure exerted onto a guide mechanism substantially similar to that depicted in FIG. 2. As depicted in FIG. 3(a), the method 300 includes (1) advancing a plurality of mail items in a first direction toward the guide mechanism 200 (block 302), wherein the guide mechanism 200 is configured to guide the plurality of mail items 102 to a transport path 106, and wherein the guide mechanism 200 has a variable angular displacement indicative of a stack pressure against the guide mechanism. The method 300 further includes a step of comparing the variable angular position of the guide mechanism 200 with a pre-determined angular displacement 216 (block 304) and a step of adjusting the stack pressure in response to the comparison (block 306).

[0041] According to another embodiment as depicted in FIG. 3(b), a method 310 is provided for guiding mail items to the transport path 106 in a mail feeding system 100 substantially similar to that depicted in FIG. 1. As depicted in FIG. 3(b), method 310 includes (1) advancing a first mail item and a second mail item in a first direction of a feeding device (block 312), wherein the feeding device 100 is configured to guide the first and the second items to the transport path 106, (2) monitoring on the transport path 106 a gap between the first mail item and the second mail item (block 314) and (3) adjusting at least one behavior of the feeding device in response to the gap between the first mail item and the second mail item (block 316). According to this embodiment, the feeding device may be substantially similar to the guide mechanism 200 as depicted in FIG. 2.

[0042] In the previous description, numerous specific details are set forth, such as specific materials, structures, processes, etc., in order to provide a better understanding of the present subject matter. However, the present subject matter can be practiced without resorting to the details specifically set forth herein. In other instances, well-known processing techniques and structures have not been described in order not to unnecessarily obscure the present subject matter.

[0043] Those skilled in the art will recognize that the methodologies presented herein may be controlled or implemented by one or more processors/controllers, such as one or more computers (ref. numeral 170 in FIG. 1). Typically, each such processor/controller is implemented by one or more programmable data processing devices. The hardware elements, operating systems and programming languages of such devices are conventional in nature and it is presumed that those skilled in the art are adequately familiar therewith.

[0044] FIGS. 4 and 5 provide functional block diagram illustrations of general purpose computer hardware platforms. FIG. 4 illustrates a network or host computer platform, as may typically be used to implement a server. FIG. 5 depicts a computer with user interface elements, as may be used to implement a personal computer or other type of work station or terminal device, although the computer of FIG. 5 may also act as a server if appropriately programmed. It is believed that those skilled in the art are familiar with the structure, programming and general operation of such computer equipment and, as a result, the drawings should be self-explanatory.

[0045] For example, sorter server 114 may be a PC based implementation of a central control processing system like that of FIG. 5, or may be implemented on a platform configured as a central or host computer or server like that of FIG. 4. Such a system typically contains a central processing unit (CPU), memories and an interconnect bus. The CPU may contain a single microprocessor (e.g. a Pentium microprocessor), or it may contain a plurality of microprocessors for configuring the CPU as a multi-processor system. The memories include a main memory, such as a dynamic random access memory (DRAM) and cache, as well as a read only memory, such as a PROM, an EPROM, a FLASH-EPROM, or the like. The system memories also include one or more mass storage devices such as various disk drives, tape drives, etc.

[0046] In operation, the main memory stores at least portions of instructions for execution by the CPU and data for processing in accord with the executed instructions, for example, as uploaded from mass storage. The mass storage may include one or more magnetic disk or tape drives or optical disk drives, for storing data and instructions for use by CPU. For example, at least one mass storage system in the form of a disk drive or tape drive, stores the operating system and various application software as well as data, such as sort scheme instructions and image data. The mass storage within the computer system may also include one or more drives for various portable media, such as a floppy disk, a compact disc read only memory (CD-ROM), or an integrated circuit non-volatile memory adapter (i.e. PC-MCIA adapter) to input and output data and code to and from the computer system.

[0047] The system also includes one or more input/output interfaces for communications, shown by way of example as an interface for data communications with one or more other processing systems. Although not shown, one or more such interfaces may enable communications via a network, e.g., to enable sending and receiving instructions electronically. The physical communication links may be optical, wired, or wireless.

[0048] The computer system may further include appropriate input/output ports for interconnection with a display and a keyboard serving as the respective user interface for the processor/controller. For example, a printer control computer in a document factory may include a graphics subsystem to drive the output display. The output display, for example, may include a cathode ray tube (CRT) display, or a liquid crystal display (LCD) or other type of display device. The input control devices for such an implementation of the system would include the keyboard for inputting alphanumeric and other key information. The input control devices for the system may further include a cursor control device (not shown), such as a mouse, a touchpad, a trackball, stylus, or cursor direction keys. The links of the peripherals to the system may be wired connections or use wireless communications.

[0049] The computer system runs a variety of applications programs and stores data, enabling one or more interactions via the user interface provided, and/or over a network to implement the desired processing, in this case, including those for processing document data as discussed above.

[0050] The components contained in the computer system are those typically found in general purpose computer systems. Although summarized in the discussion above mainly as a PC type implementation, those skilled in the art will recognize that the class of applicable computer systems also encompasses systems used as host computers, servers, workstations, network terminals, and the like. In fact, these components are intended to represent a broad category of such computer components that are well known in the art. The present examples are not limited to any one network or computing infrastructure model-i.e., peer-to-peer, client server, distributed, etc.

[0051] Hence aspects of the techniques discussed herein encompass hardware and programmed equipment for controlling the relevant document processing as well as software programming, for controlling the relevant functions. A software or program product, which may be referred to as an "article of manufacture" may take the form of code or executable instructions for causing a computer or other programmable equipment to perform the relevant data processing steps regarding document printing and associated imaging and print quality verification, where the code or instructions are carried by or otherwise embodied in a medium readable by a computer or other machine. Instructions or code for implementing such operations may be in the form of computer instruction in any form (e.g., source code, object code, interpreted code, etc.) stored in or carried by any readable medium.

[0052] Such a program article or product therefore takes the form of executable code and/or associated data that is carried on or embodied in a type of machine readable medium. "Storage" type media include any or all of the memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the relevant software from one computer or processor into another, for example, from a management server or host computer into the image processor and comparator. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution.

[0053] Hence, a machine readable medium may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the sorting control and attendant mail item tracking based on unique mail item identifier. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media can take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer can read programming code and/or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0054] While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.

Claims

1. A method for operating a mail feeding system, the method comprising steps of:

advancing (302, 312) a plurality of mail items (102) in a first direction toward a guide mechanism (200), the guide mechanism (200) configured to guide the plurality of mail items (102) to a transport path (106), wherein the guide mechanism (200) has a variable angular displacement indicative of a stack pressure against the guide mechanism (200);

comparing (304) the variable angular displacement of the guide mechanism (200) with a pre-determined angular displacement (218); and

adjusting (306) the stack pressure in response to the comparing step by advancing one or more of the plurality of mail items (102) in a second direction opposite to the first direction or by reducing a speed for advancing the plurality of mail items (102) in the first direction.

2. The method of claim 1, wherein the adjusting step is performed during active operation of the transport path (106).

3. The method of claim 1, further comprising the steps of:

determining whether the variable angular displacement of the guide mechanism (200) is greater or equal to the pre-determined angular displacement (218);

generating a first control signal in response to a result of the determination; and

adjusting the stack pressure in response to the first control signal.

4. The method of claim 3, wherein the guide mechanism (200) has one or more belts (206) driven by a guide motor (202) and the one or more belts (206) drive the plurality of mail items (102) to the transport path (106).

5. The method of claim 4, further comprising:

deactivating the guide motor (202) in response to the first control signal.

6. The method of claim 4, further comprising:

increasing a rotational speed of the guide motor (202) in response to the first control signal and the presence of mail items (102) proximate to the guide mechanism (200).

7. The method of claim 1, further comprising the steps of:

monitoring (314), prior to entry to the transport path (106), a distance between a first mail item and a second mail item of the plurality of mail items (102) guided by the guide mechanism (200) to the transport path (106);

adjusting (316) the guide mechanism (200) from a first to a second feed rate in response to the distance between the first mail item and the second mail item and profile data associated with the first and second mail item; and

feeding the second mail item at the second feed rate onto the transport path (106) based on the adjusting step.

8. The method of claim 7, wherein the profile data includes one or more of: a magazine belt speed profile, stack pressure sensor thresholds, gripper belt speed profile, sensor status, gap or pitch threshold and job characteristic data.

9. The method of claim 7, wherein the monitoring step further comprises:

detecting a first edge of the first mail item and a second edge of the second mail item; and

calculating pitch as the time duration between the first edge of the first mail item and the second edge of the second mail item.

10. The method of claim 7, wherein the monitoring step further comprises:

detecting a second edge of the first mail item and a first edge of the second mail item; and

calculating the gap as the time duration between the first edge of the first mail item and the second edge of the second mail item.

11. The method of claim 7, wherein the step of adjusting further comprises:

detecting a subsequent mail item proximate to the guide mechanism (200); and

adjusting a rotational speed of a belt motor (130) which is configured to advance the plurality of mail items (102) to the guide mechanism (200).

12. The method of claim 9, wherein the step of adjusting further comprises:

comparing the calculated pitch to a specified minimum pitch threshold;

determining a difference between the specified minimum pitch threshold and the calculated pitch; and

adjusting the guide mechanism (200) from a first feed rate to a second feed rate respective to the determined difference in order to meet the specified minimum pitch threshold.

13. A feeder system comprising:

a variable speed magazine (107) for driving a plurality of mail items (102) in a direction toward or away from a transport path (106) of a sorter;

a guide mechanism (200) for guiding each of the plurality of mail items (102) onto the transport path (106);

one or more guide mechanism sensors (230) for continuously measuring a variable angular displacement indicative of a stack pressure against the guide mechanism (200); and

a feeder control system (170) for maintaining a consistent rate at which mail items (102) are guided from the magazine (107) onto the transport path (106) by the guide mechanism (200),

wherein in response to an indicated stack pressure the feeder control system (170) drives the magazine (107) in the direction toward or away from the transport path (106).

14. The system of claim 13, wherein the feeder system responds to profile data including one or more of: magazine belt speed profile, stack pressure sensor thresholds, gripper belt speed profile, sensor status, gap or pitch threshold and job characteristic data..

15. The system of claim 13, further comprising:

one or more gripper belts (206) associated with the guide mechanism (200) capable of being driven in at least two speeds, the gripper belts (206) suitably contacting at least one of the plurality of mail items (102) as it is driven by the magazine (107); and

one or more sensors (220a, 220b) for monitoring a distance between successive mail items (102) fed onto the transport path (106) by said guide mechanism (200);

wherein in response to the monitored distance the feeder control system (170) adjusts the speed of the gripper belts (206).

Drawing