Brother MFC9100C Service Manual page 205

Trouble
(7) Print edges not aligned
(8) Ink splash
(9) Random missing dots
Jobs enclosed by parentheses (♦ ) require the special adjustment jig.
At the printer
• Check the alignment of vertical print lines by using the
maintenance-mode function code 65. (Refer to Chapter V,
Section 3.11).
• Check the print head unit.
• Check the encoder strip for stains or scratches. (♦ If the
encoder strip is not hooked properly, correct it.)
At the printer
• For each of the four ink-jet units, perform the head purging
operation several times to remove dust or air bubbles from its
nozzles.
• Check the ink cartridges. Any of them has run out of ink or the
ink viscosity has been increased, so replace it.
• Replace the print head unit.
• Replace the main PCB
• Replace the power supply PCB.
• (♦ Adjust the head-platen gap by turning the eccentric bushings
on the carriage rail.)
At the printer
• For each of the four ink-jet units, perform the head purging
operation several times to remove dust or air bubbles from its
nozzles.
• Check the ink cartridges. If any cartridges have run out of ink,
replace them.
• Check the dimple contact between the print head PCB and the
carriage PCB. Clean it if contaminated.
• Replace the print head unit.
(♦ If the problem persists, replace the carriage ASSY.)
• Check the connection of the head flat cables on the main PCB.
(♦ If either of those cables is broken or damaged, replace the
carriage ASSY.)
• Replace the main PCB
• (♦ Adjust the position of the purge unit.)
• (♦ Clean the purge cap of the purge unit with the head cleaner.
If the wiper or the pump of the purge unit is defective, replace
the purge unit.)
VI - 21
Action to be taken