Brother Facsimile Equipment MFC7420 - Manual (Page 223)

Confidential 9-35
I-9 White vertical streaks
User Check
(1) Try to wipe the scanner window with a soft cloth.
(2) The toner cartridge may be damaged. Install a new toner cartridge.
(3) Check the printer’s environment. High temperature and high humidity
conditions can cause this problem.
(4) Damp (wet) paper might be used. Try to change to freshly unpacked
paper.
Possible cause Step Check Result Remedy
Transfer
failure 1 Is the transfer roller
scratched? Yes Replace the drum unit.
Condensation 2 Has condensation occurred
inside the printer? Yes Try to print several pages or leave
the printer 2 hours to allow it to
reach room temperature.
I-10 White horizontal streaks
User Check
(1) Check the paper used meets the recommended paper specifications. A
rough surfaced paper, damp paper or thick media can cause the problem.
(2) Check that the appropriate media type is selected in the printer driver.
(3) The problem may disappear by itself. Try printing multiple pages to
clear this problem especially if the printer has not been used for a long
time.
(4) The drum unit may be damaged. Install a new drum unit.
Possible cause Step Check Result Remedy
Ground
contacts
Developing
bias contact
failure 1 Are the developing bias
contacts between the
printer body and toner
cartridge dirty? Yes Clean the electrodes at
both sides.
(4)