Brother International HL-2400C Service Manual - Page 295

I-13 White Band Phenomenon White banding line appears in the horizontal direction, and consequently causes a missing image as shown in print sample (13) of Fig.8-2. Main Causes 1) Installation failure of the transfer unit, and deformation of the transfer roller. 2) Contact failure of the transfer roller bias pole. 3) Transfer solenoid failure. Countermeasures 1) Confirm if the transfer unit is properly locked in position and that both ends of the transfer unit are held by the hooks. 2) Confirm if the transfer unit is properly installed or not. 3) Replace the transfer solenoid with a new one. (See Section 4.1.14 of Chapter VII.) 4) Replace the transfer unit with a new one. (See Section 4.6.1 of Chapter VII.) I-14 Toner Drop Phenomenon Toner spot stain is caused on the print by toner dropping within the printer engine as shown in print sample (14) of Fig.8-2. Main Causes 1) Toner drops onto the transfer drum due to the breakdown of the waste toner feeder. 1-1) Mylar of the waste toner feeder is deformed. 1-2) Waste toner is not properly collected by the waste toner feeder. Drum Cleaner Mylar Cleaning brush Toner drop Transfer Drum Waste toner feeder Fig.8-9 2) Toner adhering to the developer roller drops on the OPC belt . Countermeasures 1) Check the cleaning brush and waste toner feeder. 1-1) Clean the perimeter of the cleaning brush installation location. 1-2) Check if the seal is deformed or damage. If there is any deformation or damage, replace the waste toner feeder with a new one. 1-3) Check if waste toner is stuck in the printer engine. Remove the waste toner with a vacuum cleaner designed to manage toner. 2) Remove the toner cartridge. 2-1) Clean the surface of the developer roller. 2-2) Replace the toner cartridge with a new one. VIII-50