PIXMA MP780 - not printing black chararcters
All the people in this forum with a Canon ink printer not printing
black, especially if you tried replacing the print head and still have
the same problem.
Your purge unit/capping assembly is most likely clogged. This can be
caused by using crappy ink cartridges and by not using the printer for
exptemely long periods of time.
You will have to disassemble the printer. First open the lid so the
print head moves into the centre of travel. Unplug the power cord.
Remove the upper case (can be hard to do, usually they're
Remove one screw on either side of the print engine and remove the
engine from the lower case. Unplug the cables that go from the main
board to the purge unit (the large black assembly covered with old ink,
located on the right side of the printer where the head usually would
stop after you've finished using the printer and shut it off).
Now you have to remove that black purge unit from the right side of the
engine. Usually there are two screws holding it in place.
Give the unit a bath, carefully removing old ink from everything so the
unit looks like new. (be sure to remove the one motor first or you will
ruin the motor). Check the bottom and make sure the two small clear
rubber tubes are not clogged with old ink. Clean the absorber off (the
pad in the lower case) if it has ink piled into a small hill shape.
If the tubes look like they might be clogged, you'll have to find a way
to clear them out. I can do it in my shop, but it's too in depth to
Reassemble the printer, connect to a PC and do a few deep cleans and print out a test page. Problem solved.
Remember, if one colour is not working it's because the head is
clogged. You will have to do multiple cleans to get it to work. If it
still doesn't work, then either it's REALLY clogged or the purge unit
is not working because it's clogged. If you buy a new print head, then
the only thing left is the purge unit. Be brave and try the disassembly
and cleaning, or take it to your local service shop.
We charge $45 CDN for a job like this.
Rule of thumb: If you can get it fixed at a shop for 1/2 prince of a new unit, go for it.
Jan 02, 2008 |
Canon PIXMA MP780 All-In-One InkJet...