Brother International HL-3400CN Service Manual - Page 314

CHAPTER 8 TROUBLESHOOTING 1-15 White Spot / Black Spot Phenomenon White spots and black spots appear on the print as shown in print sample (15) of Page 8-46. Main Causes (1) Foreign particles adhering to the OPC belt or transfer drum. (2) The OPC belt or transfer drum is damaged. (3) Foreign particles mixed in the toner. (4) Foreign particles adhering to the transfer roller, or local deformation of the transfer roller. Countermeasures (1) Remove the OPC belt cartridge. 1-1) Lightly wipe off the foreign particles adhering to the OPC belt using a cotton cloth. 1-2) Replace the damaged OPC belt cartridge with a new one. (See Section 4.1 of Chapter 6.) (2) Open the transfer unit, and check the transfer drum. 2-1) Lightly wipe off the foreign particles adhering to the transfer drum using a cotton cloth. 2-2) Replace the damaged transfer drum with a new one. (See Section 4.8 of Chapter 6.) (3) Remove the toner cartridge. 3-1) Clean the surface of the developer roller. 3-2) Replace the toner cartridge with a new one. (4) Replace the transfer unit with a new one. (See Section 4.6.1 of Chapter 7.) 1-16 Mixed Color Image Phenomenon Mixed color image appears in the print as shown in print sample (16) of Page 8-46. Main Causes (1) Failure of toner cartridge: Blade pressure of the developer roller is incorrect or the blade is deformed. (2) Restitution error of toner cartridge. Countermeasures (1) Confirm the toner cartridge can be inserted smoothly. (2) Replace the toner cartridge with a new one. (3) Reconfirm that the front cover unit is locked. 8-56