Brother International HL-2400C Service Manual - Page 289

I-3 Jitter Phenomenon Uneven optical density appears periodically in the horizontal direction on the printed image as shown in print sample (3) of Fig.8-2. Main Causes Failure of main motor. 1) Irregular rotation of the drive motor. 2) Failure of the gears. 3) Variation of OPC belt running speed due to above reasons. 4) Too much rotational load of the OPC belt. Countermeasures 1) Replace the main motor with a new one. (See Section 4.1.8 of Chapter VII.) 2) Replace the OPC belt cartridge with a new one. (See Section 2.1 of Chapter VI.) Note: If the print mode is set to CAPT (Color Advanced Photoscale Technology) in the driver, this problem might occur. Change the mode setting to normal mode. I-4 Ribbing Phenomenon Light print occurs on the right or left hand side of the image as shown in print sample (4) of Fig.8-2. Main Causes 1) Slight tilt on the surface of printer installation table. (Tilt should be less than 1°.) 2) Toner amount in the toner cartridge is insufficient. (The amount in a full cartridge should be 175g for Y, M, & C and 275g for K.) 1 Fig.8-3 Countermeasures 1) Confirm that the printer installation table is flat and level. 2) Replace the toner cartridge with a new one. VIII-44