Thank you for using the Support Forum. Make sure that you do not have draft mode turned on in the driver. Select High Resolution in the Print Quality drop down and you should have the 1200x2400. Please consider contacting your support centre for further assistance.
Thanks, CherylO-Xerox Community Manager
Be sure to click Kudos for those who have helped you. Select Accept as Solution for posts that have helped to solve your issue(s)!