Ink Splash; Print Edges Not Aligned; Random Missing Dots - Brother MFC640CW Service Manual

Problem

(7) Ink splash

(8) Print edges not aligned

(9) Random missing dots

Printer
• 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 head/carriage unit.
• Replace the main PCB.
• Replace the power supply PCB.
• Replace the maintenance unit.
Printer
• Check the alignment of vertical print lines using maintenance-
mode function code 65. (Refer to
• Check the head/carriage unit.
• Check the CR encoder strip for stains or scratches. (If the CR
encoder strip is not hooked properly, correct it.)
• Correct the positioning error of the head/carriage unit. (Refer
to Chapter 6, Section 6.2, [ 3
Printer
• 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 that the carriage-head flat cable is connected to the
carriage PCB.
• Replace the head/carriage unit.
• Check the connection of the head flat cables on the main PCB.
(If either of those cables is broken or damaged, replace it.)
• Replace the main PCB.
• Clean the head caps and wiper of the maintenance unit with a
Rubycel stick. For the cleaning procedure, refer to
Section 7.1 "CLEANING THE MAINTENANCE UNIT."
• Replace the maintenance unit.
9 - 3 3
Action to be taken
Chapter 8, Section
].)
8.4.14.)
Chapter 7,
Confidential