Please check the following points to solve the problem:
Clean the primary corona wire inside the drum unit by sliding the green tab. Be sure to return the green tab to the home position.
Please refer to the instructions, "Clean the corona wire of the drum unit.".
The drum unit may be damaged. Put in a new drum unit.
Please refer to the instructions, "REPLACE DRUM".
DCP-L2520DW, DCP-L2540DW, DCP-L2550DW, DCP-L5500DN, DCP-L5502DN, DCP-L5600DN, DCP-L5602DN, DCP-L5650DN, DCP-L5652DN, DCP-L6600DW, HL-2130, HL-2135W, HL-2220, HL-2230, HL-2240, HL-2240D, HL-2270DW, HL-2275DW, HL-L2300D, HL-L2305W, HL-L2315DW, HL-L2320D, HL-L2325DW, HL-L2340DW, HL-L2350DW, HL-L2360DW, HL-L2370DW(XL), HL-L2380DW, HL-L2390DW, HL-L2395DW, HL-L5000D, HL-L5100DN, HL-L5102DW, HL-L5200DW(T), HL-L5202DW, HL-L6200DW(T), HL-L6202DW, HL-L6250DW, HL-L6300DW, HL-L6400DW(T), HL-L6402DW, MFC-L2680W, MFC-L2685DW, MFC-L2690DW, MFC-L2700DW, MFC-L2705DW, MFC-L2707DW, MFC-L2710DW, MFC-L2720DW, MFC-L2730DW, MFC-L2740DW, MFC-L2750DW(XL), MFC-L5700DW, MFC-L5702DW, MFC-L5705DW, MFC-L5800DW, MFC-L5802DW, MFC-L5850DW, MFC-L5900DW, MFC-L5902DW, MFC-L6700DW, MFC-L6702DW, MFC-L6750DW, MFC-L6800DW, MFC-L6900DW, MFC-L6902DW