Some Questions and Answers Evenly spaced, repeated marks on the page. Evenly spaced, repeated dots, or a fine line from the top of the page to the bottom means that your toner cartridge OPC drum has been damaged in some way. The only way to solve this problem is to replace the cartridge with another one.
Printing is too light or too dark.
The most common reason that your printing is too light or too dark on the left or the right side is the doctor blade is set incorrectly. Another reason is that you need to set your print density setting on your laser printer. Check your printer manual for information on this procedure. A dirty cartridge corona wire mostly causes random black and vertical lines. To solve this problem you need to clean the wire with the brush provided with your laser printer.