Our WorkCentre 4118X is not networked or connected to a PC, it is standalone. Our copies are too light. Even when we adjust using the lighten/darken button all the way to dark for an individual copy, it still is not dark enough. This problem seems to have worsened over time. We have changed toner & drum. We can not find any kind of setup accessible to us to adjust darkness/contrast. Any help will be greatly appreciated.