Lexmark C912 Service Manual - Page 194

5055-xxx Duplex unit A duplex unit can be optionally installed in the main unit, allowing two-sided printing. Selecting Paper feeding, Registration, Transfer, Separation, Fusing, or Face-Down paper discharging with the pulse motor in the duplex unit, feeding is stopped before the paper is delivered. Paper delivery is then reversed and fed to the duplex unit. Paper fed with the duplex unit stops once, and the center position is corrected by the operation of the side guide plate. Paper is then refed by the printer controller signal to the main unit, and, following printing on the back side, is delivered to the normal feeding path. When non-offset type color toner is used, the process speed in the OHP mode is decreased, causing toner to melt sufficiently with the fusing unit, while the fusing temperature is set higher than usual to increase the smoothness on the surface of the toner image. This mode restricts paper feeding to multipaper feeding, not cassette feeding. 3-44 Service Manual