by adding sophistication to the software routines that keep track of the usage of high frequency service items ( hfsi ) parts in a document processing system , we can improve the predictability of these routines . this will reduce the amount of waste and customer dissatisfaction that comes from replacing parts either too early or too late . system modeling techniques can be used to represent the relative amount of component stress that a given job contains . one example is to keep track of the number of image pitches that actually take place during cycle - up / cycle - down and count them for all of those subsystems that are impacted . another example is to use pixel counting to determine the area coverage and use that information to scale the count by the proportional amount of stress that it represents . the predictability of the current approach can be improved if certain operational characteristics are taken into consideration . the broad teaching here is for the use of estimated or model derived print / copy count adjustments to the hfsi counters that can correlate relative stress levels between certain types of machine usage with the expected life of the various machine subsystems . fig1 depicts a flow chart with the broad concepts pertaining to the teachings of the present invention . input block 100 is the number of “ clicks ” or other incremental count or system input data for a part being monitored as is typically already collected in present prior art systems . of course , in the alternative , for any input data from the part being monitored that is not currently being collected , a new data collector would need to be implemented . in a copier / printer system , for example , the input data being monitored would typically be the number of copies , although there are many other possible parameters such as operation hours . the input from block 100 is then passed into usage condition weighting blocks 101 - 105 and 108 . these weighting conditions for this embodiment comprise usage block 101 environment , block 102 paper type , block 103 image type , block 104 job type , block 105 job length and block 108 recovery . weighting considerations for usage block 101 environment would be parameters of temperature and humidity . the weighting considerations for paper type usage block 102 would be concerned with the media type such as transparencies verses paper , as well as paper thickness and weight . image type considerations as weighed in at block 103 are toner coverage metrics as determined by examining the incoming image data and , in pursuit thereof , may be as simple as pixel counting or involve more complex digital imaging manipulation techniques . in usage block 104 , job type considerations such as job requirements for simplex / duplex , covers , and inserts , are the weighting factors . usage block 105 provides a weighting factor as provided for job run length which allows the difference in stress to the system depending upon whether a single page is copied / printed or many copies / prints are generated for a single job . finally , in usage block 108 weighting considerations due to the stress of system recovery from system problems are provided for . a couple of illustrative examples as found in printer / copier systems follow below . in electrostatic - graphic printer / copier document processing systems , for example , it is a well - known fact that short run jobs are more stressful than long run jobs . one reason for this is the percentage of the total job resources consumed by machine cycle - up and cycle - down . in fact , for very short print / copy length jobs , the cycle - up / down may account for more machine stress than the process of making the prints does . that is because cycle - up is used to prepare the system for printing . the belt or drum is charged and given time to reach electrical equilibrium . measurements are taken of test patches to determine the appropriate charge and bias levels and to calibrate the control system . this must be done each time because the belt continuously changes its electrical properties over time . some setup procedures have an iterative component so time is required to complete that . at the same time , the fuser and the illumination lamp ( where applicable ) are warming up . the cleaner is also run to clean the belt of any dust or debris that might have fallen or settled since the last job . for a typical machine , it is not unusual for 10 or more photoreceptor panels to pass by the transfer zone before the first sheet is fed . during this time , many of the key machine subsystems ( e . g . p / r , developer , and charge ) are being exercised in much the same way that they are during the actual print job . copy / print quality adjustments may consume many machine resources without contributing to the “ click ” count input to block 100 at all . cycle - down is generally shorter . it is primarily used to run the cleaner after the job is complete and move waste toner into the sump . some diagnostic test routines may also be run during this time . any paper that is still in the system must be purged out as well to bring the machine back to a ready - to - run condition . it is important then to count those extra photoreceptor panels as usage for those subsystems rather than relying solely on the sheets fed and printed . so , if a given printer / copier machine runs ten blank photoreceptor panels before making the first print , and a customer runs 3 images , the enhanced hfsi counters for those impacted sub - systems would provide for a count of 13 rather than three . the output of usage block 105 will provide a weighted count to account for just such a scenario . over a long period in which many short run jobs are made , the counts could be quite different than what a simple print counter will show . in the case of a 1000 sheet run , the 10 cycle up copies would be negligible reflecting the is fact that the relative impact of cycle up in a long run is negligible . another usage mode provided for by usage block 103 in the fig1 model is % area coverage . since the amount of toner on an image can affect the stress on the developer , p / r , cleaner , and fuser , a proportionality factor is used . for example , if a basic text document with 10 % area coverage were considered nominal , a pictorial image with 35 % coverage would tend to stress those subsystems more . it is unlikely however that this document is really 3 . 5 times as stressful in terms of reliability and wear . detailed modeling , or empirical data , would provide an influence factor for area coverage . the influence factor would moderate the effect of area coverage by a given percentage . for example , it may be determined that the influence of area coverage is 20 % at most . that would mean that from a wear perspective a dark dusting ( 100 % coverage ) would generate the equivalent of 2 copy counts per page as shown below : in other words , actual coverage divided by the nominal coverage and multiplied times the influence factor would generate the weighting factor that is then the output of usage block 103 . it will be apparent to one skilled in the art that embodiment with additional sophistication can be added to this . for example , in another embodiment , not only area coverage but also density can be included . in a yet a further alternative embodiment , a direct pixel count of the input data image can be used . other stress factors addressed by usage block 102 are paper size and paper weight . there are a number of stresses well known in the printer / copier arts . for example , there is the 11 ″ wear mark on fuser rolls . a favorable mix of 14 ″ sheets could actually reduce the stress on the fuser and , thus , independently keeping track of 11 ″ sheets would be beneficial . heavy weight papers can stress drive elements , requiring more torque . transparencies can stress fuser rolls because of higher adhesion forces and the higher fusing temperatures required to improve color transparency performance . de - lamination of fuser rolls is a function of the integral of temperature and time and the magnitude of the thermal gradients that the fuser must endure . all these can contribute to the life expectancy calculation of this high cost replacement item as determined in usage block 102 . the usage block 108 for recovery , provides for the stress various replaceable elements incur in system breakdown situations like power failure or power interruption , and as is often experienced in document processing systems , paper jam . the wear patterns so incurred can vary significantly depending upon where the jam occurs and on when in the job cycle the jam occurs . the stress during recovery may further vary depending on the kind of print job being executed as well . returning to fig1 the weighted counts as determined by the weighting factors in the usage blocks 101 - 105 and 108 are combined at summation block 106 . in one preferred embodiment as shown at block 107 , the resultant summation from summation block 106 is expressed as an equivalent number of system cycles or “ clicks ” although they need not be an integer quantity . it may also comprise a fractional part of a “ click ”. the idea is that the customer or field engineer for whom this is provided is most comfortable in determining the need to replace a serviceable unit working within the paradigm of copy counts or “ clicks ”. this representation is also more compatible with information systems that deal with replacement intervals in these same terms . however , it will be apparent to those skilled in the art other representations maybe used . fig2 depicts the process flow for smart copy count correction from system recovery showing the accommodation of startup cycle down and paper path jam impact factors in a copier embodiment . starting with block 200 , user input determines a selection of some initial number of copies “ n ”. then as depicted at block 201 , the print job begins . an increment of “ s ” copy clicks , as shown at block 202 , is included to cover the startup impact . the number “ s ” may be ten as discussed above , however , this is machine dependent and will , therefore , vary from system to system . concurrent with the startup impact increment of block 202 , the print job will request the appropriate number of sheet feeds 203 . each sheet feed will increment the nominal main copy counter 205 as is shown at step 204 . the sheet feed block 203 will then initiate an assessment of any jam conditions at decision block 206 . if there are indeed jam conditions , then at step 207 the supplemental diagnostic copy counters 208 are incremented by “ j ”. this number will vary from system to system and may even vary depending upon the type of jam . for example , a jam during a duplex job will involve clearing the duplex paper path as well as the simplex paper path . the table 1 which follows provides one example embodiment scenario : in the above table , the “ side 1 jam ” event is the simplex paper path situation . notice that no extra “ clicks ” are to be incremented for the duplex supplemental diagnostic copy counter 208 in that situation since that portion of the machine is not affected by the event . however , for a “ side 2 jam ” event which involves the duplex paper path , there is a tally of 10 clicks for the duplex supplemental diagnostic copy counter 208 . so the “ j ” increment in step 207 is 10 for the duplex supplemental diagnostic copy counter 208 in that situation . in step 209 , a summation of startup “ s ” and cycle - down ( or job end ) “ e ” click increments are allotted . typical incremental “ click ” values are provided in the table 1 above for the photoreceptor , cleaner , fuser , duplex developer , and registration transport of a document processing system in the jam condition startup and cycle - down situations provided for in step 209 . note that the equivalent values for the cleaner are particularly high , since in the case of a jam , the cleaner must remove the entire untransferred image as opposed to the residual amount of toner left after the image has been transferred to paper as it typically does . the summation performed at step 209 can include weighted counts combined with recovery counts from jam conditions , plus startup and cycle - down counts . when needed , step 211 provides for a clear and continue system reset , providing system sheet purge , and initiating operator diagnostics . the supplemental diagnostic copy counter 208 is updated in count by the summation of the nominal main count “ n ”, the jam count “ j ”, the startup “ s ” and the cycle - down “ e ” counts to yield a much more robust and meaningful indicator of cru and hfsi wear replacement scheduling in a document processing system . the clear and continue block 211 , or if there was no jam the jam decision block 206 , toggle decision block 210 where a comparison between the sheet counter and the print job copy number “ n ” is used to determine if the print job has completed or if the counter should be decremented and a sheet feed command issued to block 203 to repeat the above described sequence until the job is done . once decision block 210 determines that the job is complete , step 212 provides for the summation of “ e ” job cycle - down impact clicks into the supplemental diagnostic copy counters 208 and directs the system to a job stop at step 213 . it will be understood by those skilled in the art that a paper jam is just one example of several types of recovery conditions . while a paper jam has been used as an illustrative example however , the same recovery strategies apply to any type of recovery condition for both a fault recovery situation or for a hard shutdown scenario . more specifically , knowledge of the type of fault or shutdown is to be used to further modify the recovery impact counts . a shutdown recovery can occur as the result of a sheet of paper physically stubbing or lodging at a specific location in the paper path . in another scenario it could occur as the result of a sheet delay due to reduced motor speed or slippage between the driving roll and the paper , causing the sheet to arrive outside the allotted time window . a simple fault recovery could occur as the result of a system software error condition or a hard shutdown could ensue from perhaps an electrical power surge that would cause the abnormal termination of the controlling software program and possible reboot . all of these possible recovery scenarios will involve the same typical situation in a document processing system , which is that the machine has come to a stop with one or more sheets in the paper path and one or more images at various stages of construction on the photoreceptor belt or drum . typically there will be a latent image where the charged portion of the belt has been exposed to the image generating light source , as well as a developed image on the photoreceptor where toner has been applied but not yet transferred to paper . furthermore , there will be a residual image on the photoreceptor that has not yet entered the cleaner and a sheet of paper with a toner image that has not yet entered the fuser . the recovery procedure will require that all of these sheets be removed from the paper path and the photoreceptor returned to its nominal condition . this process of recovery will create stress levels on the machine that will in many instances be several orders of magnitude higher than what is normally encountered . fig3 provides an alternative recovery mode embodiment . recovery mode weighting factors and counter increment counts (“ clicks ”) are preferably adjusted depending upon the severity and type of recovery or jam scenario . in a document processing system and , in particular , in an electrostaticgraphic type system , the impact to a transfer drum or transfer belt and their attendant cleaning systems will vary depending upon at what point in the copying cycle the jam interrupt occurs . if , for example , all toner has been transferred from the belt onto paper sheets and then a jam or recovery interrupts , there will be little impact to the belt and its cleaning system . however , if as more likely to happen particularly in a image - on - image color system , the toner happens to be on the belt when a recovery interruption occurs , there will be a very large strain upon the cleaning system in dealing with the abnormal load . this in turn means a considerably higher amount of wear for the both the cleaning system as well as the transfer belt . the difference in load for the cleaner between normal operation and jam clearance may be as much as 1000 times greater . furthermore , the amount of toner is dependent upon the image which was to be transferred . so , in one embodiment , digital imaging techniques are employed to compare a nominal typical toner coverage and compare it to the actual input image and thereby actual indication of toner upon the belt . this ratio is utilized as an area coverage influence factor and adjusted in impact for each given subsystem . above , in table 1 , the column for high area coverage lists these influence factors for each subsystem as an example embodiment . the influence factor is applied as a multiplier against the equivalent sheet count which is also multiplied by the ratio for a given sheet &# 39 ; s actual area coverage relative to nominal sheet coverage . given a nominal 10 % area coverage the resulting impact of a jam of an 80 % coverage sheet on the cleaner would be 100 sheets as shown in the following formula : 25 equivalent sheets × 80 %/ 10 %× 0 . 5 ( table 1 cleaner influence factor )= 100 . so what starts as an initial 25 “ clicks ” becomes 100 clicks because of higher than nominal area coverage . starting at block 200 in fig3 user input determines a selection of some initial number of copies “ n ”. then as depicted at block 201 , the print job begins . an increment of “ s ” copy clicks may be included to cover the startup impact . the number “ s ” may be ten as discussed above , however , this is machine dependent and will , therefore , vary from system to system . concurrent with the startup impact increment , the print job will request the appropriate number of sheet feeds 203 . the sheet feed block 203 will then initiate an assessment of percent area coverage at block 300 , as discussed above , and provide an area coverage ratio “ ac ” at block 302 . each sheet feed initiation of block 300 will also increment the nominal main copy counter 205 as is shown at step 204 . with the increment main copy counter step 204 , a determination of jam conditions is made at decision block 206 . if a jam scenario is detected , the next step is to calculate the jam impact at block 304 . this pulls the example table 1 data from memory with location / register 306 providing the equivalent copies e i data and memory location 308 the influence factor i i . as described above , these factors and equivalent copy numbers are multiplied and the result then multiplied against the area coverage ratio ac . jam impact j i = i i × e i × ac . this final “ click ” count result j i is then used to increment the appropriate supplemental diagnostic copy counter 208 which , in this example , would be the counter for the cleaner . when needed , the next step 211 provides for a clear and continue system reset , providing system sheet purge , and initiating operator diagnostics . the step that follows ( or if there was no jam condition determined at decision block 206 ) is to toggle decision block 210 where a comparison between the sheet counter and the print job copy number “ n ” is used to determine if the print job has completed or if the counter should be decremented and a sheet feed command issued to block 203 to repeat the above described sequence until the job is done . once decision block 210 determines that the job is complete , it directs the system to a job stop at step 213 . in closing , employing supplemental counters and inputting both additional startup / rundown considerations , as well as scenario modified recovery counts into those supplemental counters , results in greater accuracy in determining and thereby predicting component end of life wear time . furthermore , application of this methodology will allow appropriate replacement schedules to be instituted and updated which will thereby minimize both cost and customer down time . while the embodiments disclosed herein are preferred , it will be appreciated from this teaching that various alternative , modifications , variations or improvements therein may be made by those skilled in the art . for example , it will be understood by those skilled in the art that the teachings provided herein may be applicable to many types of document processing systems including copiers , printers and multifunction scan / print / copy / fax machines with computer , fax , local area network , and internet connection capability . further , the techniques herein described above may be applied to many different subsystems in the prior listed document processing systems . all such variants are intended to be encompassed by the following claims .