OfficeJet and Inkjet printers only have 2 critical components to printing. The cartrdige/ink is the first and the print head is the other. On most models the printhead and cartridge are installed together. In higher end models they are seperate.
Since you have already tried to clean the print heads your next steps are either to swap the cartrdige or the print heads. You can figure out if the cartrdige is bad if you happen to have a 2nd 4622 lying around. All you would need to do is try the cartrdige in a different pritner and see if they work or not. If you dont have a spare 4622 available then you will have to take a best guess.
In very rare cases the carriage itself is damaged and unable to opperate any of the print heads or cartridges. Most of the time the printer will be able to detect that as a part of its pre boot initialization test. Considering you dont have any error messages I would try swapping heads and cartridges first. Last resort is to swap the whole printer since swapping a rriage is generally a bad sign and time for replacement anyways.