Brother International HL 1850 Service Manual - Page 172

CHAPTER 6 TROUBLESHOOTING (4) Others Condensation: When the printer is moved from a cold room into a warm room in cold weather, condensation may occur inside the printer, causing various problems as listed below: • Condensation on the optical surfaces such as the scanning mirror, lenses, the reflection mirror and the protection glass may cause the print image to be light. • If the photosensitive drum is cold, the electrical resistance of the photosensitive layer is increased, making it impossible to obtain the correct contrast when printing. • Condensation on the corona unit may cause corona charge leakage. • Condensation on the hopper plate and separation pad may cause paper feed troubles. If condensation has occurred, print several pages or leave the printer for 2 hours to allow it to reach room temperature. If the drum unit is unpacked soon after it is moved from a cold room to a warm room, condensation may occur inside the unit, which may cause incorrect images. Instruct the user to allow the unit to come to room temperature before unpacking it. This will take one or two hours. 1.2 Warnings for Maintenance Work To avoid creating secondary problems by mishandling, follow the warnings below during maintenance work. WARNING (1) Always turn off the power switch and unplug the power cord from the power outlet before accessing any parts inside the printer. (2)Some parts inside the printer are extremely hot immediately after the printeris used. When opening the front cover or rear cover to access any parts inside the printer, never touch the red coloredparts shown in the following figures. it ' --' I\ g 6-2