Problems printing correct colors with PIxma MG7720

[jeanbean67]

Hoping someone can help. Didn't find the answer on Google. My printer has been working just fine till now. All of a sudden, it only prints gray instead of black. I use only Canon cartridges. I have taken out and reinstalled all of them making sure they are seated properly. The only cartridge that might be tripping things up is an empty skinny black cartridge but I have been printing just fine without it being refilled as I haven't had time to get to the store. The PG black cartridge is full. Nozzle check works great, all the colors, including the black look fine. Unplugged and replugged printer back in. Not sure what to try. next. I am reluctant to do a deep cleaning because it says it will use a lot of ink to do that.  Any help on this would be greatly appreciated! Thank you.

[Ramona]

Hi jeanbean67,

When a nozzle check pattern prints correctly, it will look like the image shown here.  If the nozzle check pattern did not print correctly, we recommend replacing any empty ink tanks in the unit, then performing a print head alignment on the printer by following the steps shown here.  Should this not resolve the issue, you can try performing the deep cleaning to see if this will help.  Should the issue continue, we ask that you please contact a Canon technical support representative here for further assistance. A representative will be happy to assist you free of charge.