Brother International HL-2400C Service Manual - Page 298

I-19 Mottle Phenomenon Variation of the scanning density is found in the image as shown in print sample (19) of Fig.8-2. Main Causes 1) The transfer unit is not fixed in place. 2) Assembly of the transfer roller is inaccurate. 3) THV output of DC high voltage unit is not normal. 4) Failure of the toner cartridge. 5) Deformation of the print paper. Countermeasures 1) Confirm that the transfer unit is firmly locked in place. 2) Confirm that the transfer roller is properly installed. 3) Replace the DC high voltage unit with a new one. (See Section 4.3.2 of Chapter VII.) 4) Replace the toner cartridge with a new one. 5) Replace the paper with new paper from a freshly opened ream. I-20 Residual Image Phenomenon Image of the preceding page appears on every other page as shown in print sample (20) of Fig.8-2. Main Causes 1) Cleaning failure due to lifting of the cleaning brush of the drum cleaner. 2) Contact failure of the drum cleaner's bias pole. 3) Failure of DC high voltage unit. Countermeasures 1) Check if the drum cleaner is properly installed or not. 2) Replace the failed DC high voltage unit with a new one. (See Section 4.3.2 of Chapter VII.) VIII-53