Brother MFC L5900 Light copies when copying off glass (Prints fine from PC)

[Doug James]

The copy's off the glass are noticeably slighter lighter than the prints. If you adjust the density to dark they look fine. I cleaned the optics. Is there a way to adjust the exposure density in service mode to just affect the copies off the glass and not the prints ? Thanks so much for any help !!

[Elmtech]

If you execute maintenance mode function 55 this initializes the white level data for the CIS.

[Doug James]

If you execute maintenance mode function 55 this initializes the white level data for the CIS.

Thanks so much,Really appreciate your help !!!