Printer for solid colors?

I've used the Xerox Phaser 7400 and although it's fast and has good resolution, it can NOT print solid colors without ghosting and banding. I was told this is due to the toner going direct to the paper instead of the transfer belt.

I'd like to print solid color flyers and business cards. Could the Xerox Phaser 7800 or Oki Pro 9431 handle this? Speed and resolution aren't important but coverage quality is.

Also, do you have experience with Oki Smart contract? Looking for a managed print service without hidden limits.