Printer with a driven print media carriage

1. A printer that comprises

a chassis;

a print media tray arranged on the chassis and displaceable with respect to the chassis;

a drive mechanism mounted on the chassis and engaged with the print media tray to displace the print media tray with respect to the chassis;

a controller to control the drive mechanism, the controller including a user interface to allow a user to actuate the drive mechanism; and

an ink jet printhead assembly mounted in the print media tray to print on the sheets of print media

wherein the print media tray includes one or more roller wheels that are engageable with the chassis to facilitate displacement of the tray and ink jet printhead assembly with respect to the chassis.

2. A printer as claimed in claim 1 , wherein the chassis includes a pair of elongate rails that are configured so that the wheels can travel along the rails.

3. A printer as claimed in claim 1 , in which the controller includes a sensor that is configured to sense manual urging of the print media tray and to provide the drive mechanism with a suitable control signal so that the drive mechanism displaces the print media tray in a direction of said urging.

4. A printer as claimed in claim 3 , wherein the sensor is further configured to detect any stoppage of the print media tray during displacement in one direction and to provide the drive mechanism with a suitable control signal so that the drive mechanism displaces the print media tray in an opposite direction.

5. A printer as claimed in claim 1 , in which a roller assembly is mounted on the chassis and configured to pick sheets of print media from the print media tray.