US Patent 7527359 Circuitry for printer

A print head has an array of jets formed in a jet stack to deliver ink to an image receptor and at least one ink reservoir to deliver ink to the jet stack. Control circuitry is arranged on the jet stack with an actuator array arranged on the control circuitry to cause the reservoir to deliver ink in response to signals from the control circuitry. A ground plane is arranged between the actuators and the ink reservoir. A print head has an array of jets formed into a jet stack to deliver ink to a printing medium and an actuator array formed on the jet stack, each actuator separated from other actuators by gaps. A spacer is arranged on the jet stack so as to fill the gaps between the actuators.