I have this idea for a HP or other type of printer hack. Which is to have arduino move all of the motors in the printer and control the flow of ink onto the paper... anyone have ideas?
Controlling the motors should not be too difficult. Most smal inkjet type printers have either one stepper motor and one DC motor or two stepper motors. Usualy a stepper is controling the paperfeed and a DC mortor is moving the printhead.
Controlling the ink flow is probably more difficult, you would need acces to detailed information on how it works before you can have Arduino control it.