Background in 2 sided copies in bizhub 420

[moonwalker3778]

Dear experts,

Iam facing a problem in bizhub 420,the prob is while doing 2 sided copies background is appearing only on the second side.when doing single side copies no issues.

Pls give me the solution. The Drum & Developer life is 70K copies.

Thanks in advance

[barratec]

Try to change the developer. That model of machine often doesn't reach the established end of life.

[mick75]

try to adjust the second transfer, in the negative direction, if your in a low humidity area, they have problems with transfer. Is this just plain paper or heavy stock?

[moonwalker3778]

its just plain paper.if i change new dev prob ll fix but again appears after 50k copies and becomes worse.

[Sjeuf]

Please check the connection to ground !!
check also the if the voltage is correct

sjeuf