The most common cause of poor print quality and missing colors is debris build-up on the print head. Run your printer's print head cleaning utility (instructions typically found in your user manual). If the problem persists, you will need to remove the individual cartridges and ensure the contact and cable surfaces are free of ink residue. If there is some, you can clean them with cotton swabs and clean water by wiping the residue away gently.
After doing all the steps mentioned above, you will then need to print a test page to check if it's working correctly. If unsure how to do this, feel free to check our 'How To Test Print?' page for the step-by-step guide for printing a test page.
To prevent this issue in the future, run the print head cleaning function as often as the manufacturer recommends.