Abstract:
A capability is provided to reduce misregistration effects, and/or color-to-color registration errors, in output multi-color images based on velocity and position deviations and/or disturbances in transfer subsystems in image forming devices. A capability is provided to automatically compensate for torque disturbances caused by a photoreceptor belt seam crossing a mechanical device in a photoreceptor belt-based transfer subsystem in an image forming device. A learning algorithm, based on a mathematical model of transfer subsystem mechanical operational dynamics by which a series of performance curves could be generated, is employed to facilitate prediction of a torque disturbance profile in a mechanical motor driven transfer subsystem in an image forming device in order to produce a response profile which automatically predictively attempts to nullify the effects of the mechanical torque disturbance.

Description:
BACKGROUND 
   This disclosure is directed to systems and methods for incorporating a learning algorithm for adaptive feed forward control to assist in automatically rejecting repetitive torque disturbances for mechanically moving parts in image forming devices. 
   A variety of systems of methods are conventionally used to perform electrophotographic and/or xerographic image production and/or reproduction in image forming devices. One common system includes a transfer subsystem that further includes an electrophotographic photoreceptor belt. 
     FIGS. 1 and 2  illustrate a side elevation view and a front elevation view, respectively, of a schematic of a transfer subsystem  100 , which includes a photoreceptor belt  110 . A photoreceptor belt motor drive unit  122  engages the photoreceptor belt  110  and moves the photoreceptor belt  110  across a series of support rollers  124 ,  130 ,  132 ,  134 ,  142 ,  144 ,  146 , and/or a plurality of non-rotating support bars  152 ,  154 ,  156 ,  158 . 
   Typically, photoreceptor belts are fabricated from long sheets of photoreceptor material that are cut to size. The ends of the cut photoreceptor material are welded, or otherwise mated, together in order to form a continuous belt. This fabrication process produces a photoreceptor belt seam  115  at the point where the ends of the photoreceptor belt  110  are welded, or otherwise mated, together. 
   Some transfer subsystems, such as the one shown in  FIGS. 1 and 2 , include an acoustic transfer assist (ATA) module  120 , which draws the photoreceptor belt  110  into a plenum using a vacuum. The ATA module  120  vibrates the photoreceptor belt  110  in the plenum to aid in transferring toner from the photoreceptor belt  110  to an image receiving medium. 
   In areas of the photoreceptor belt  110  where there is no seam, a tight vacuum is maintained in the ATA module  120 . However, when the photoreceptor belt seam  115  of the photoreceptor belt  110  crosses the ATA module  120 , the vacuum seal is momentarily broken. Drag of the photoreceptor belt  110  on the photoreceptor belt motor drive unit  122  momentarily reduces causing the photoreceptor belt motor drive unit  122  to speed up. Speed of the photoreceptor belt motor drive unit  122  must be tightly controlled for reasons that will be discussed in greater detail below. Photoreceptor belt velocity sensors (not shown) sense the increase in velocity of the photoreceptor belt motor drive unit  122 . A motor control device reacts to readjust the speed of the photoreceptor belt motor drive unit  122  and the photoreceptor belt  110 . 
   Even a momentary perturbation in photoreceptor belt velocity during imaging affects imaging results by, for example, producing defects in output hard-copy images transferred to an image receiving medium. Color photoreceptor belt-based systems include a plurality of imaging stations, each for a different one of a plurality of primary colors. An output multi-color spectral image is produced when toner particles of one or more of the primary colors are attracted to a respective one of a plurality of identical transfer images electrostatically formed in a plurality of discrete positions for each single primary color on the photoreceptor belt  110 . As the photoreceptor belt  110  passes over the image receiving medium, toner is transferred one color at a time to the image receiving medium. Each of the primary colors of toner particles mix with any previously laid down on the image receiving medium in an image-on-image transfer process. A single pass of a plurality of transfer images, each laden with a single primary color on the photoreceptor belt, forms the mix of colors necessary to produce and/or reproduce the output color image on the image receiving medium. 
   Precise control of the velocity and the position of the photoreceptor belt  110  is necessary in order to attempt to ensure that each of the plurality of separate single color images is precisely overlaid on the image receiving medium in order to produce the output color image. When individual single color images do not correctly align, based mechanical transients and/or disturbances in the transfer subsystems such as, for example, velocity and/or position mismatches, or transient errors in control of the photoreceptor belt  110 , image quality will decrease because the colors do not precisely line up. Such defects in output hard-copy images in electrophotographic and/or xerographic image forming devices are referred to alternatively as misregistration of colors or color-to-color registration errors. Such misregistration of colors may initially fall below any detectable threshold, but increases, i.e., becomes more pronounced and/or noticeable, as image-on-image systems and/or system components age or wear under use. 
   SUMMARY 
   The mechanical operating dynamics of a transfer subsystem, and/or photoreceptor belt module, can be modeled mathematically. Parametric studies have been undertaken in an analysis space using mathematical models, and mechanical transients, such as those related to photoreceptor belt velocity, which may occur from any number of sources including, for example, a photoreceptor belt seam passing over an ATA module, are recorded. 
   New U.S. Patent Application entitled “Systems and Methods for Reducing Torque Disturbance in Devices Having an Endless Belt” by Kevin M. Carolan, filed on May 5, 2005 under Xerox Ser. No. 11/118,488, which is commonly assigned and the disclosure of which is incorporated herein in its entirety by reference, teaches a control system to compensate for motion disturbances which may cause defects in multi-color output images produced by image forming devices, particularly those image forming devices which include transfer subsystems centered around a photoreceptor belt transfer device. The disclosed system may include a controller that determines when a torque disturbance is expected to occur and controls the photoreceptor belt motor drive unit with a compensation amount that may be retrieved from a data structure, such as, a pre-stored lookup table or a mathematical algorithm that is not specifically defined. This compensation amount from the data structure may be adjusted via a gain factor and may be combined with the output of a closed loop compensator at a summation point. The output has the form of a predetermined curve of a specific shape, and with a specific timing of a repetitive torque disturbance, to attempt to minimize the misregistration effect produced by the torque disturbance in the output images produced by the image forming device. Ser. No. 11/118,488 employs a timing methodology to anticipate the onset of a disturbance and via the controller attempts to insert an opposing profile that causes the photoreceptor belt motor drive unit to generate an opposing torque to substantially nullify the disturbance. Amplitude of a correction profile, corresponding to the amplitude of the disturbance, is manually adjusted to attempt to minimize the effects of the disturbance on the produced output images, for example, the color-to-color registration error. The controller monitors the onset of the disturbance or predicts the onset of the disturbance based on sensed photoreceptor belt position and encoder timing. Actuator parameters are adjusted based on preadjusted manually input correction factors to attempt to minimize the effects of the disturbance. Correction factors for the current operating state of the transfer subsystem in the image forming device are obtained substantially through a trial and error method. 
   It would be advantageous if, instead of requiring manual input and/or adjustment of the feed forward correction factors to an FFC device, a system or method could be provided to automate and/or adapt an FFC profile to match precisely the timing and nature of a torque disturbance in a transfer subsystem. Such a system or method may reduce or substantially nullify torque disturbances, such as, for example, torque disturbances caused by a photoreceptor belt seam passing over an ATA in a photoreceptor belt-based transfer subsystem in an electrophotographic and/or xerographic image forming device. 
   Exemplary embodiments of disclosed systems and methods may provide a leaning algorithm using a correlated model of system dynamics to compensate for torque disturbances in mechanical systems, such as, for example, transfer subsystems, in image forming devices. 
   Exemplary embodiments of disclosed systems and methods may employ a learning algorithm, based on a mathematical model of transfer subsystem mechanical operational dynamics by which a series of performance curves could be generated. The learning algorithm may allow prediction of a torque disturbance profile in a mechanical motor driven transfer subsystem in an image forming device in order to produce a response profile which predictively attempts to nullify the effects of the mechanical torque disturbance. 
   Exemplary embodiments of disclosed systems and methods may provide a learning algorithm which can be used to determine a width, start position and height of a correction factor, based on sensed maximum and minimum disturbed velocities in the photoreceptor belt motor drive unit, and the positions at which these velocities occur in a belt movement cycle referenced to a belt position reference point. These correction factors are provided as inputs to, and/or through, an FFC device to predictively correct motor velocity for a pending torque disturbance which may be, for example, caused by a photoreceptor belt seam crossing an ATA. 
   Exemplary embodiments of disclosed systems and methods may provide a capability to reduce misregistration effects, and/or color-to-color registration errors, in output images based on velocity and position deviations and/or disturbances in photoreceptor belt-based transfer subsystems in image forming devices. 
   These and other features and advantages of the disclosed embodiments are described in, or apparent from, the following detailed description of various exemplary embodiments of the systems and methods. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various exemplary embodiments of disclosed systems and methods will be described, in detail, with reference to the following figures, wherein: 
       FIG. 1  illustrates a schematic side elevation view of a transfer subsystem for an image forming device including a seamed photoreceptor belt; 
       FIG. 2  illustrates a schematic front elevation view of a transfer subsystem for an image forming device including a seamed photoreceptor belt; 
       FIG. 3  is a schematic block diagram of an exemplary system for implementing a learning algorithm for producing feed forward correction factors and implementing feed forward control of a mechanical operating system within the transfer subsystem of an image forming device; and 
       FIG. 4  is a flowchart outlining an exemplary method for implementing a learning algorithm to produce feed forward correction factors and to implement feed forward control of a mechanical operating system within the transfer subsystem of an image forming device. 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   The following description of various exemplary embodiments of automated and/or adaptive feed forward control systems and methods for predictively adjusting a mechanical velocity of a transfer subsystem to compensate for mechanical torque disturbances in the transfer subsystem in an image forming devices may refer to and/or illustrate one specific type of transfer subsystem, a seamed photoreceptor belt-based transfer subsystem, for the sake of clarity, familiarity, and ease of depiction and description. However, it should be appreciated that the principles disclosed herein, as outlined and/or discussed below, can be equally applied to any known, or later-developed, system in which, based on some measurable mechanical disturbance which may corrupt constant speed and related positioning of a repetitive mechanical input, the mechanical disturbance can be controlled, and the effects of such disturbance reduced and/or nullified. 
   Various exemplary embodiments of disclosed systems and methods may automate a capability to reduce, and/or substantially eliminate, out-of-specification color-to-color registration errors in output hard copy images produced by, or reproduced in, electrophotographic and/or xerographic image production and/or reproduction devices. 
   A general location regarding where in the mechanical cycle of the transfer subsystem of the transient is going to occur is known. Based on this knowledge, a manual feed forward control method has previously been implemented. This manual feed forward control method has been shown to be effective in reducing transients such as those caused by torque disturbances. This objective is accomplished by providing manual inputs to a feed forward control (FFC) device to command a photoreceptor belt motor drive unit through a profile that counteracts the transient just as, or slightly before, the transient occurs. 
   A learning algorithm, according to the systems and methods disclosed herein, is intended to automate, and thereby make more efficient, determination of the timing and the size of the feed forward correction profile. This disclosure responds to a need to provide a system and method for automating and adapting FFC profile generation in individual image forming devices. 
   Various exemplary embodiments of disclosed systems and methods may allow simple information to be measured from actual transients experienced by the mechanical transfer subsystem in operation. Specifically, the measured parameters may include maximum belt velocity experienced during a disturbance and minimum belt velocity experienced during a disturbance. With these parameters, referenced to a belt position at which each occurs, the nature of the disturbance may be characterized. A responsive set of correction factors may then be precalculated. These correction factors, characterizing a correction profile, may then be input to, or through, an FFC device to control the velocity of, for example, a photoreceptor belt motor drive unit as a repetitive torque disturbance, e.g., a seam crossing an acoustic transfer assist (ATA) unit, approaches. The FFC device maintains substantially constant speed of the mechanical system, for example, the photoreceptor belt, through the transient torque period. 
   Various exemplary embodiments of disclosed systems and methods may compute a start point, height and width of a disturbance in order to obtain correction factors representing a correction profile for current operating conditions of an image forming device. Such a correction profile may be obtained at regular intervals, or on an as-needed cycle, in order that feed forward control can be implemented through an FFC device such that torque disturbances in such image forming devices are minimized. 
     FIG. 3  is a schematic block diagram of an exemplary system  200  for implementing a learning algorithm for producing feed forward correction factors and implementing feed forward control of a mechanical operating system within the transfer subsystem of an image forming device. As shown in  FIG. 3 , the system  200  may include a user interface  210 , a system controller  220 , an algorithm storage device  230 , a correction factors computation device  240 , and a correction factors storage device  250 , which are interconnected, as appropriate, by a data/control bus  270 . The system  200  also may include a transfer subsystem  260 . The transfer subsystem  260  may further include a photoreceptor belt motor drive unit  268 , a photoreceptor belt velocity sensor  262 , a photoreceptor belt position sensor  264 , and a feed forward control (FFC) device  266 . The photoreceptor belt velocity sensor  262 , photoreceptor belt position sensor  264 , and FFC device  266  receive individual inputs from, or send individual control inputs to, the photoreceptor belt motor drive unit  268 . These sensors  262 ,  264  and the FFC device  266  are also interconnected with the data/control bus  270  in order to provide information to, or receive information from, other system elements. 
   In various exemplary embodiments, as part of a warm-up cycle, or other pre-print cycling of the image forming device, the photoreceptor belt motor drive unit  268  is started. The FFC device  266  is not activated at that point and, as such, no correction factor is input to the photoreceptor belt motor drive unit  268 . Reference is made to photoreceptor belt position by employing a photoreceptor belt position sensor  264 . Photoreceptor belt position may be detected by, for example, detecting a hole or mark in the photoreceptor belt by the photoreceptor belt position sensor  264 . The photoreceptor belt position sensor  264  may comprise an optical sensor, magnetic sensor, mechanical sensor, or any other suitable sensor. 
   A plurality of belt cycles may be undertaken as part of a warm-up cycle for the image forming device. On each cycle, the photoreceptor belt velocity is measured by a photoreceptor belt velocity sensor  262 . The photoreceptor belt velocity sensor  262  may be an optical sensor, magnetic sensor, mechanical sensor, or any other suitable sensor. The photoreceptor belt velocity sensor  262  may be implemented by the photoreceptor belt position sensor  264  and a timing device by, for example, timing the interval between detection events completed by the photoreceptor belt position sensor  264 . Alternatively, for example, the photoreceptor belt velocity sensor  262  may detect velocity based on rotational speed of the photoreceptor belt motor drive unit  130  ( FIG. 1 ) or any other rotating element contacted by the belt. 
   A rudimentary profile of photoreceptor belt velocity versus photoreceptor belt position is obtained based on inputs from the photoreceptor belt velocity sensor  262  and the photoreceptor belt position sensor  264 . These inputs either individually, or in a correlated manner, are input to the correction factors computation device  240 . The measurements of photoreceptor belt position and photoreceptor belt velocity are conventionally undertaken to enable the system to provide control of the speed of the photoreceptor belt motor drive unit  268  under varying operating conditions. 
   Maximum and minimum photoreceptor belt velocity values are measured and recorded on each of the plurality of photoreceptor belt cycles. These values are preferably measured over a series of non-printing cycles by the photoreceptor belt velocity sensor  262  and the photoreceptor belt position sensor  264 , but may be measured over a series of printing cycles as well. The series of values for each of the maximum photoreceptor belt velocity and minimum photoreceptor belt velocity, correlated to the photoreceptor belt position where each occurred on each cycle, are fed to the correction factors computation device  240 . Each of the series of maximum photoreceptor belt velocities, minimum photoreceptor belt velocities, and corresponding photoreceptor belt positions is averaged. The result is an average value for each of the maximum photoreceptor belt velocity, the minimum photoreceptor belt velocity, average photoreceptor belt position where each of the average maximum photoreceptor belt velocity and the average minimum photoreceptor belt velocity can be referred to occur for this particular set of operating conditions, and the current condition of the transfer subsystem. 
   With the computed average values for the above parameters, a set of feed forward correction factors can be determined. These include width of the correction factor, starting position of the correction factor, and height of the correction factor. The correction factors are related to the respective width, start point and height of the torque disturbance. 
   An example regarding calculation of a set of feed forward correction factors will now be undertaken employing a set of algorithms, the constant values (C 1 -C 8 ) of which may be analytically derived for an exemplary image forming device. In order to determine width of (W d ) torque disturbance for the exemplary image forming device analytically, an analytical model of the imaging system is exercised for a range of torque disturbance widths. A plot of the positional difference between the maximum and minimum velocity points v. the disturbance pulse width yields a linear relationship whose best fit line was determined to satisfy the following equation:
 
 W   D   =C 1*( P   max   −P   min )+ C 2  (Equation 1)
 
where:
     W D  is the width of the disturbance in seconds;   P max  is the photoreceptor belt position of the maximum photoreceptor belt velocity (as averaged);   P min  is the photoreceptor belt position of the minimum photoreceptor belt velocity (as averaged); and   C 1  is the analytically determined slope of the best fit line for the plot of (Pmax−Pmin) v. disturbance width; and   C 2  is the analytically determined Y-intercept of the best fit line for the plot of (Pmax−Pmin) v. disturbance width.
 
Photoreceptor belt position is measured referenced to a specific photoreceptor belt position indicator reference, for example, a photoreceptor belt reference hole.
   W D , in seconds, is then equal to W FFC  or the width of the feed forward correction, in seconds.   

   In order to determine the start position of the feed forward correction factor, the system may employ the position of the point of maximum photoreceptor belt velocity (P max ), i.e., the distance of the point of maximum photoreceptor belt velocity from the photoreceptor belt hole sensor, and the width of the disturbance (W D ) as computed above. First, from the analytically derived equations such as those determined for the exemplary image forming device here, the system may solve for a positional offset according to the following equation:
 
 P   off =( C 3× W   D )+ C 4  (Equation 2)
 
where:
     P off  is a positional offset factor based on the width of the disturbance (W D ); and   C 3  and C 4  are analytically determined constants based on exercising the model over a range of disturbance widths and start positions, and plotting the results in the form of P max  vs P DS  for different values of W D .   

   The disturbance start point for this exemplary image forming device is then calculable based on the following equation:
 
 P   DS =( C 5× P   max )+ P   off   (Equation 3)
 
where:
     P DS  indicates the position of the start of the disturbance, and the start position for inputting the feed forward correction factor (P FFC ); and
 
C 5  represents an additional analytically determined constant based exercising the model over a range of disturbance widths and start positions, and plotting the results in the form of P max  vs P DS  for different values of W D , as above.
   

   With the width of the disturbance (W D ), and therefore the width of the feed forward correction (W FFC ), in seconds, and the point at which the disturbance starts (P DS ) and therefore the position at which the feed forward correction needs to start (P FFC ) calculated, a third feed forward correction factor to be determined regards the height of the feed forward correction factor (H FFC ). This height will be based on the height of the disturbance. Analytically for the exemplary system, it was determined that contour lines for disturbances of differing heights for the exemplary image forming device all pass through a point C 6  on the Y-axis of a standard X-Y plot. As such, a first component of the calculation may be to determine the slope (S) of a contour line on which a point (V max -V min , W D ) lies according to the following equation: 
                 S   =         W   D     -     C   ⁢           ⁢   6           V   max     -     V   min                 (     Equation   ⁢           ⁢   4     )               
With this slope (S) calculated, the height of the disturbance (H D ) may be determined according to the following equation:
 
                   H   D     =       S   +     C   ⁢           ⁢   7         C   ⁢           ⁢   8               (     Equation   ⁢           ⁢   5     )               
where constants C 6 , C 7  and C 8  are derived analytically by plotting (V max −V min ) v. W D  for a range of disturbance heights, H D .
 
   Width of the disturbance (W D ) is equal to width of the feed forward correction factor (W FFC ) in seconds, and position of the disturbance start (P DS ) is equal to the position at which the feed forward correction should start (P FFC ). Height of the feed forward correction (H FFC ), on the other hand, may not correlate on a one to one basis with height of the disturbance (H D ). For example, H FFC  was experimentally established for the exemplary image forming device to be determined according to the following equation:
 
 H   FFC =round(10 ×H   D )  (Equation 6)
 
   Having determined the three factors that determine the nature of the feed forward correction profile (W FFC , P FFC , and H FFC ), a feed forward correction profile is now defined. The feed forward correction profile can be output from the correction factors computing device  240  to the FFC device  266 . When image printing commences, the feed forward correction profile is in place via the FFC device  266  to automatically reduce misregistration effects and/or color-to-color registration errors due to torque transients. Registration errors on the order of approximately 60 microns may be reduced to registration errors on the order of, for example, less than 35 microns, which are typically viewed as being within acceptable registration deviation limits. 
   It should be appreciated that, given the inputs of maximum photoreceptor belt velocity and minimum photoreceptor belt velocity based on the disturbance, with associated photoreceptor belt positions at which these points occur, software algorithms, hardware and/or firmware circuits, or any combination of software, hardware and firmware control elements, may be used to implement the individual computational devices and data storage units in the exemplary system  200 . 
   It should be further appreciated that the individual devices and/or units depicted in  FIG. 3  as internal to the exemplary system  200  could be either discrete devices, units and/or capabilities internal to the system  200 , or may be presented individually, or in combination, attached as separate devices and/or units connected by any path that facilitates data communication and coordination between such devices and/or units such as, for example, one or more of a wired, a wireless, and/or an optical digital data transmission connection. Though presented as discrete elements, it should be recognized that the capabilities represented by the discrete elements depicted in  FIG. 3  may be integrated into a single software algorithm, hardware and/or firmware circuit, or otherwise in any combination of such components. 
   Any of the data storage units depicted, or alternately as described above, may be implemented using any appropriate combination of alterable, volatile or non-volatile memory, or non-alterable, or fixed, memory. The alterable memory, whether volatile or non-volatile, may be implemented using any one or more of static or dynamic RAM, a computer disk and compatible disk drive, a writable or re-writable optical disk and associated disk drive, a hard drive, a flash memory, a hardware circuit, a firmware circuit, or any other like memory medium and/or device. Similarly, the non-alterable, or fixed, memory may be implemented using any one or more of ROM, PROM, EPROM, EEPROM, an optical ROM disk, such as a CD-ROM or DVD-ROM disk with a compatible disk drive; or any other like memory storage medium and/or device. 
     FIG. 4  is a flowchart outlining one exemplary method for implementing a learning algorithm to produce feed forward correction factors and implement feed forward control of a mechanical operating system within the transfer subsystem of an exemplary image forming device. 
   As shown in  FIG. 4 , operation of the method begins at step S 1000  and continues to step S 1200  where the system warm-up routine of the image forming device commences. Operation of the method continues to step S 1300 . 
   In step S 1300 , a plurality of sensing cycles commence. Operation of the method continues to step S 1400 . 
   In step S 1400 , on each of the plurality of sensing cycles, photoreceptor belt position is sensed by a belt position sensor. Photoreceptor belt position is typically referenced to some standard photoreceptor belt position indicator such as, for example, a belt hole or mark. Operation of the method continues to step S 1500 . 
   In step S 1500 , photoreceptor belt velocity is measured as the photoreceptor belt travels through a full rotation, or a single cycle, of the plurality of sensing cycles. Photoreceptor belt velocity may be discretely or continuously referenced to photoreceptor belt position. Operation of the method continues to step S 1600 . 
   It should be appreciated that photoreceptor belt position and photoreceptor belt velocity are conventionally sensed in order to attempt to control speed of the photoreceptor belt motor drive unit within acceptable limits. Photoreceptor belt position is sensed with respect to a reference point. In the disclosed system, photoreceptor belt velocity is referenced to photoreceptor belt position through each cycle of the photoreceptor belt. 
   In step S 1600 , a determination is made whether the plurality of sensing cycles is complete. The number of sensing cycles for a given system may be manually or automatically input as part of the sensing routine, and may remain constant or may be variable based on other operating conditions. 
   If a determination is made in step S 1600  that the required number of a plurality of sensing cycles is complete, the operation of the method continues to step S 1700 . 
   If a determination is made in step S 1600  that the required number of a plurality of sensing cycles is not complete, the operation of the method returns to step S 1400  and photoreceptor belt velocity and photoreceptor belt position continue to be sensed through the rest of a plurality of sensing cycles until the required number of sensing cycles is determined to be complete at step S 1600 . 
   In step S 1700 , average values of the maximum sensed photoreceptor belt velocities and the minimum sensed photoreceptor belt velocities are individually computed. Additionally, an average value for that photoreceptor belt position at which each of the averaged maximum photoreceptor belt velocity and the averaged minimum photoreceptor belt velocity values occurs through the plurality of cycles is also computed. Operation of the method continues to step S 1800 . 
   In step S 1800 , correction factors are computed according to a set of analytically derived equations for the specific image forming device that are then stored in the system. Such a set of equations was analytically derived for an exemplary image forming device and is listed in paragraphs [0034]-[0038] above. Operation of the method continues to step S 1900 . 
   In step S 1900 , the computed correction factors of height (H FFC ), width (W FFC ), and start position (P FFC ) for the feed forward corrections are fed to a feed forward control device. Operation of the method continues to step S 2000 . 
   In step S 2000 , the feed forward control device applies the computed correction factors in order to drive the photoreceptor belt motor drive unit velocity in such a manner to reduce the effect of repetitive torque disturbances thereon. Operation of the method continues directly to step S 2400 , or alternatively to optional step S 2100 . 
   In step S 2100 , the system is commanded to produce a test image on an image receiving medium. Operation of the method continues to step S 2200 . 
   In step S 2200 , a manual or automated evaluation of the test image is performed. Operation of the method continues to step S 2300 . 
   In step S 2300 , a determination is made as to whether misregistration of colors, or color-to-color registration error, is below registration threshold value in the test image. 
   If in step S 2300  a color-to-color registration error is above registration threshold value, the system returns to step S 1300  and another plurality of sensing cycles is undertaken. 
   If in step S 2300  color-to-color registration is below the registration threshold value, the operation of the method continues to step S 2400 . 
   In step S 2400 , the requested series of multi-color output images commanded of the image forming device are printed. Operation of the method continues directly to step S 2800 , or alternatively to optional step S 2500 . 
   In step S 2500 , correction factors calculated for the transfer subsystem in the image forming device based on current operating conditions are verified. Operation of the method continues to step S 2600 . 
   In step S 2600 , verified correction factors may be stored in a data storage unit within the image forming device for future reference. Operation of the method continues to step S 2800 . 
   In step S 2800 , operation of the method stops. 
   It should be appreciated that, although the disclosed systems and methods have been described in conjunction with a conventional color image-on-image printing device, wherein a transfer subsystem is centered around a mechanically motor driven photoreceptor belt, the depictions and descriptions are illustrative and not meant to be in anyway limiting, particularly not limited to such a narrow application as any single color image printing device and/or any transfer subsystem that may be deemed to require a photoreceptor belt. 
   It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art, and are also intended to be encompassed by the following claims.