ok i give up , i have a unit out there that is producing backround all over the copy like it was over exposed but its not... i have replaced
the dv unit it worked for a day then right back to crappy copies , i replaced the drum unit and transport section , and still nothing changes...
it almost looks like bad dv bias , i need help....
You said you replaced the DV unit and worked for a day and problem returned.
Sounds like you may have contaminated toner or a bad toner sensor.
You may need to clean out the toner hopper (make sure the bottom transport coil has no damage), replace the DV (and make sure it calibrates properly) if not replace the toner sensor as well. If it is bad, it could be overtoning causing the background. Also make sure to use OEM toner.
** don't use your vacuum on the DV unit with the toner sensor still on it.
try to clean up charge corona and the grid with liquid soap and warm water. i have a problem like this a view weeks ago with a e studio55 after cleaning it works like new!
saluti harry
I had an 853 start giving background after about 160k it turned out Developer bias conection in back of machine fell off. reinstalled and changed developer havent herd from cust. since.
thanks guys for all the help, i did manage to reset all the dv bias settings to factory spec (one of them was way off)
put in a new grid and reset the drum...
everything seems to be cool now....
Toshiba e studio 80 backround on the copies 
Linear Mode
