I've found that if they don't respond to your prodding after 2 years you toss them and get a new printer.
Do try the usual print head clean 2 dozen times.
Also, does a self test print come out OK?
I have two Canon InkJet printers. Canon BJC 2000 not work apsolutely. When I push Up the printer cover, printer head don't move to centrall position, printer do nothing. I measure voltage on SMPS and everything is O.K. (24V, 5V).
Second printer is Canon S200SPx. Problem is incorect printing pages. Picture with blue color this printer prints like red, after reset PC something printing is O.K but pure.