1. A method of collecting diagnostic data for a printer, the method comprising: generating at least one of cover sheets and/or electronic versions of the cover sheets, the cover sheets and/or electronic versions of the cover sheets identifying documents having substantive sheets being printed by the printer; routinely collecting the generated cover sheets and/or electronic versions of the cover sheets; and preserving at least some of the collected cover sheets and/or electronic versions of the cover sheets as a historical record of the output of the printer over a time period, wherein the historical record of the cover sheets and/or electronic versions of the cover sheets includes data which is used to diagnose image quality issues and potential image quality issues related to the documents processed by the printer.