My printer is only printing in black in. No color is printing at all. I have a lexmark Platinum Pro905 and the firmware is fully updated.

We're sorry to hear that you're having problem with your printer. That sounds like a printhead problem. Lexmark recognizes that some of our inkjet all-in-one customers may be experiencing issues with their print quality. We take our customer user experience very seriously, and we strive to ensure that each time a customer prints using a Lexmark device the page is crisp, clear and up to the highest standards.
However, if your device is displaying a 'printhead error' on the hardware and/or you are suddenly experiencing a print quality issue, please contact the Lexmark Technical Support Center at 1-800-539-6275.
Lexmark agents are prepared and able to help diagnose and resolve your issue. This may involve updating your printer firmware and/or replacing the printhead for your printer, at no charge to you, our customer. Installation is quick and easy for any customer to perform.

Try to clean the printhead. To do that, on the control panel of your printer, press on the Ink Levels > More Options > Deep Clean Printhead.

Also, make sure that you're using a Genuine Lexmark cartridges.

If it doesn't fix your problem, try to go to this link for more info: http://bit.ly/mDKqh7