HI! We've had a Xerox Phaser 7760 for many years with minimum problems! We love it. However all of a sudden our prints are turning out as the above image illustrates. Any print that contains Yellow comes out with void space where the yellow toner should be. We've replaced all the imaging drums (the yellow one twice), all of the toner, the fuser, transfer roller, and the belt cleaner assembly.
One other thing that I've discovered is that this only happens when the printer tray is set to any type of "thin" or "plain" paper. If I set the paper tray to "Thick" paper it prints perfectly, no lines.
I'm really at a loss here. Any suggestions would be appreciated.
Barber pole deletions are caused by the developer housing. Take the yellow drum out and shine a flashlight on the developer housing. You will see the the same voids there. Replace the developer housing and developer.