US Patent 7319833 Developer roller preserver

A toner cartridge adapted to fit within a toner cartridge-receiving cavity of a printer. The body of the cartridge comprises a front section, which houses the photoconductive drum common in all printers, capable of being biased in relation to the rest of the cartridge which houses the developer roller. The placement of a mechanical biasing element, or developer roller preserver, between the main body and front section creates a gap between the rigid photoconductive drum and the relatively soft developer roller. This gap prevents a “flat spot” from forming along the length of the developer roller during periods of long storage or non-use.