hp officejet pro 7720 not printing in colour at A3 format

[Frank471]

I have exactly the same problem as many users have encountered over the past 3-4 years, my HP7720 works fine with all apps with A4 paper size but switches into grayscale when either the software or the printer (or both) are set at A3 paper size. I have tried all the sequences suggested by previous suggestions with no useful effect. I have tried the 'borderless printing' solution suggested by a couple of your commentators but this has not worked for me. It is beyond comprehension that there is not a clear solution to a problem raised so many times on these pages over the years and it does provoke me to look elsewhere when I next purchase a color printer and scanner.

[Valsimot]

The solution is to go to hp.com and install the original HP print driver for that printer model, you are currently using Microsoft drivers and those are not good for A3.