Brother International HL-3400CN Service Manual - Page 309

HL-3400CN SERVICE MANUAL 1-7 White Line (2) Phenomenon Vertical white line appears from the leading edge to the trailing edge of the printed image as shown in print sample (7) of Page 8-45. Main Causes The dustproof glass of the laser unit is smeared with toner or foreign particles. Countermeasures Clean the dustproof glass. (See Section 2.8 of Chapter 6.) (1) Remove the OPC belt cartridge and toner cartridges. (2) Remove the dustproof glass from the laser unit. (3) Clean the dustproof glass. 1-8 Vertical White Band Phenomenon White band appears in the vertical direction of printed image as shown in print sample (8) of Page 8-45. Main Causes Silicone oil adhering to the transfer drum. Transfer drum Adhered silicon oil Transfer unit Transfer drum Fig. 8-6 Countermeasures (1) Wipe off the oil adhering to the transfer unit and its perimeter. (2) Replace the transfer drum with a new one. (See Section 4.8 of Chapter 6.) (3) If the oil adhesion is excessive, replace the OPC belt cartridge and drum cleaner with new ones. (See Section 4.1 and 4.5 of Chapter 6.)