Phaser 6121MFP Service Manual 2-17Theory of OperationPPM controlPPM (page per minute) control prevents the edge temperature of the heatingroller from increasing during a multi-print cycle using smaller sized media. Thedistance between fed sheets is increased according to the number of printedpages that are to be produced and the media length. This evens out thetemperature of the heating roller and thus stabilizes fusing performance of theprinted toner image.The PPM control is provided at 20 ppm for a multi-print cycle of producing 20pages. The number of printed pages per minute is established as detailed belowfor each media size for the 21st and subsequent pages.No PPM control is provided for a multi-print cycle of color printing, as it is 1/4 ofthe monochrome printing.ScannerScanner components include:• Scanner Motor and Drive Belt• Platen Glass• ScanheadFunctional components of the Scanner are illustrated below.The Scanner does not include sensors for determining the size of the originaldocument. Original media size settings are made on the Control Panel.Media Conditions PPMA5, invoice 14 ppmMedia having a narrower width and longer length than above 8 ppms6121mfp-114Scanner Motor (M101)Exposure Unit
