Xerox 4510 User Guide

There are dark spots or marks that appear in a random pattern on the page. 

The paper path may be contaminated with toner.

Print several blank sheets of paper to remove the 
toner accumulations.

The print cartridge may be defective.

Replace the print cartridge.

The fuser may be defective.

Replace the fuser (in the maintenance kit).

The transfer roller may be defective.

Replace the transfer roller (in the maintenance 
kit).