Pixma MP780 Printer, not printing

Not normally but the black print head nozzles maybe blocked.
Inkjet printers need to be used frequently to prevent ink drying out and blocking the print head nozzles.
If the print head cleaning maintenance routine does not clear the blockages, then print head needs replacing, but it may be expensive.
It may be more cost effective to buy a later model and better printer than replace the print head.

Hello!

Please check the "Rplacing an ink tank" part of the manual. Hope it will help you.
https://manualsbrain.com/en/manuals/1796179/?page=45

The black is the first to wear out on these printheads, you will need a new printhead, QY6-0049-000.
You will only waste inks trying to clean or deep clean, the best bet is to replace the printhead and if all else is ok you will get many more trouble free prints and better quality color prints.

you may have a blocked printhead, try running a clean from the printers own maintenance program
good luck

Issue: Alarm / Power light flashes orange 8 times consecutively (Waste Ink Nearly Full Error)
Solution: Press the <RESUME/CANCEL> button to clear the error (1700)
Waste ink absorber error 1700
The printer has a built-in waste ink absorber to hold the ink used during print head cleaning. Eight flashes indicates that this absorber is nearly full.

Press the <RESUME/CANCEL> button on the printer to clear the error, so you can continue the print job. The printer will need to be serviced as soon as possible.

Issue: Alarm / Power light flashes orange 8 times consecutively (Waste Ink Nearly Full Error)
Solution: Press the <RESUME/CANCEL> button to clear the error (1700)
Waste ink absorber error 1700
The printer has a built-in waste ink absorber to hold the ink used during print head cleaning. Eight flashes indicates that this absorber is nearly full.

Press the <RESUME/CANCEL> button on the printer to clear the error, so you can continue the print job. The printer will need to be serviced as soon as possible.

Hi ...

Cannon Pixma MP780 have an absorber and this error is related to this absorber.

This printer has an ink absorber that takes in ink during the printing and print head cleaning processes. The cleaning process is necessary in order to keep the print head nozzles from becoming clogged. Over the life of the printer, the amount of ink that the ink absorber has absorbed is calculated by the printer. Eventually, after substantial use, the printer will enter an error condition when the ink absorber is nearly full. At this point, printing is still possible. Press the <Stop/Reset> button to cancel the error. You will still be able to print for a short period. To protect the printer from damage, you will not be able to print at all once the ink absorber is full.
Canon recommends having the printer serviced before the absorber becomes full. Replacing the ink absorber is a complicated and potentially messy procedure. Even if the ink absorber is successfully changed, the ink absorber counter must be reset.

I would suggest that you take your printer to the nearest cannon service centre and get it repaired.

Don't forget to vote if this helps ... Cheers :)

There is a cleaning solution sold on E-bay for Cannon i470D print heads.
Or you can try a little ammonia. I used a cap full of ammonia in each side of the print head where the ink tanks go.
Put the print head in a can and let it set in the ammonia for 5-15 minutes then blot dry with paper towels and let stand until dry.
Then run the maint routines for the print head found under properties/maintance.

Try a new tank, there are more and more people getting bad ink tanks. HOWEVER if it is a printer that has seperate heads you might have to change it.

open your list of printers. r/click on the 780 and open properties. fo to the last tab "maintenance" and run cleaning 2 or 3 times then run deep cleaning 2 or 3 times. and see how this helps. If you've never done it before you might want to take out the print head and clean it with alcohol. Take out all the ink like you were changing them then reach in and gently pull out the container that holds the ink. This is the print head. Clean it and replace it, then run clean and deep clean again. run Nozzle check to see how clean it's become and you'll definetly see a difference in your printing. good luck

Will it print internal reports in color? Can you perform a maintenance head cleaning cycle?

I’m happy to help further over the phone at https://www.6ya.com/expert/jayw_0e86fb055a7b73de