PIXMA MP780 Big black

[stuber]

I posted this before back in may. I have a MP780 that has the following simptons.

I have a new print head and new ink in the printer. When I perform a nozzle check the section at the top for the BCI-3 is not there at all, only the BCI-6 color sections are printed.
If I place a black and white document on the glass and tell it to copy in black, I get a blank page. If I place a color document on the glass and tell it to print in color it prints but the black is very faint.
Scanning an faxing work fine.
If I print a text document from the computer it comes out as a blank sheet. If I print a color document from the computer it prints the color, but no black.

I have tried the soaking and the windex, none of which seems to make a difference.

I have had several people suggest the purge unit. If this is a posibility how does one go about replacing it.

Any assistance would be appreciated

 

[Tin Ho]

I believe your pigment black print head is badly clogged. You have a good chance still to unclog it. You will need a new BCI-3ebk cartridge that is in good working order when the print head is unclogged. If you use the same one that caused the clog in the first place it will be very likely to clog the print head again.

You need more agressive unclogging effort. Here is one method to try. Turn on your kitchen water faucet to produc dripping water drops like a few drops per second. Let the dripping water drops the water from high above (maybe about 8 inches?) into the ink intake for the BCI-3ebk cartridge. The force of the dripping water will give some small yet safe amount of pressure to push the dried black pigments in the print head down and out of the nozzles. Use warm water. Watch black ink dripping out from the bottom. Try to keep the PCB on the back of the print head assembly dry. You probably need to repeat this several times until the clog is cleared.

 

[ghwellsjr]

Your original question about cleaning the purge unit is answered here.