Phaser 540/550 "Number of Pages" to Expect based on Toner Coverage Area:

Below you can calculate the number of pages obtained based on the percentage fill of toner coverage. The calculations will give the low, nominal, and high values for the number of pages you can expect from a typical toner cartridge.

Key Caveat: The quoted lifetimes of a toner cartridge are the nominal "average" for that toner cartridge when print coverage is 5% per primary. They are not guaranteed minima. Actual results, even under carefully controlled 5% coverage tests will sometimes vary by as much as ±15% due to physical and environmental conditions. There will be occasional instances where customers run a majority of their images at 25% coverage or more per primary (basically 100% page coverage if all 25% primary colors are used on a single page), thus toner cartridge life will be substantially reduced. By as much as a factor of five. In this kind of environmental usage, customers will end up replacing the toner cartridges much more frequently than the "nominal" specification of 5% coverage.

Therefore, it is appropriate to set the customers expectations with a statement like "their mileage may vary" on toner usage, depending on how they use the printer. Also, the above yield estimates are averages based on 5% per primary coverage, and are not guaranteed minima. However, it is not appropriate to state toner usage as a variable with respect to coverage, both because it is not "industry standard " and because it leads people to think that yields should be completely deterministic and predictable, when in fact they are not! All we can do is make an attempt at a good estimate.

Therefore, if we provide estimates that were "bullet proof, worst case, never exceed " numbers, it would be much too pessimistic, and not representative of the average case.

However, with the above said, it may be necssary to at least give a customer some value or better yet, some range of values due to their misguided expectation of what they think they should get from a toner cartridge.

Using the "Good Estimate Formula" GEF Calculator:

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This page was last updated on 09/07/2003
Copyright, RDB Prime Engineering