First you need to ensure that this is not a driver problem, by
reinstalling drivers and testing the printer on a different computer.
Also ensure that ink cartridges are OK, try replacement inks.
If
the problem is not a software problem, and the printer is recognised by
computer, and the printout is coming as a blank or faded page, then you
usually have a faulty or clogged printhead.
Try first performing
print head cleaning procedure from printer tools, that may not fix the
problem, but do the cleaning a couple of times, just in case.
If the print head is clogged, that can be fixed soaking the print head in isopropyl alcohol overnight.
If still no luck, then the printhead must be replaced, here is the part:
Canon MULTI-PASS F-80 Print Head
$61.00