copy starts getting darker with grey background

[sbtiti]

Customer's WC 4150 works fine when first powered on but the background which should be white starts to get more and more grey as more copies are made. Could a worn out drum cause this or do I need to look at the high voltage system or other components? Any comments or suggestions will be greatly appreciated. Thank you.

[Exok]

Try a new drum first. I find the 4150 drums rarely last their regular life span.