C451-550 developer loosing

[t-rex]

Hello my colleuges,ı have a problem for bizhub c 451 or 550.Developer goes to waste toner box.I was change hv1,hv2,prcb,mfb... all pwb but my trouble contınue.Im changing IU,yes everthing is ok but after 4000-10000 copy same problem.I check it developer bias voltage,cleaning bias ,contact plates,earth plates puuuuffffff.pls help me bodys.

[mrfixit]

is this happening on every color or just black?

[t-rex]

is this happening on every color or just black?

every color.

[fixthecopier]

could the place the machines are in cause the IU's to dump. Environment can cause strange things to happen to machines. We have had machines in factories that made soaps and other cleaners. The IU's would only go a fraction of their life and when we would change the machines the same thing would happen on different machines. Do they have other printing equipment that have short life on drums?