Patent ID: 7467847

Claim:
An inkjet printing apparatus for printing an image on a printing surface of a three-dimensional object located at a printing position, the apparatus being adapted to print the image on the printing surface by printing droplets at grid points of a print grid for the image, the grid points being spaced apart at a grid pitch, wherein the apparatus comprises: a handling apparatus for supporting the object such that the object extends out from the handling apparatus into a printing region, wherein the handling apparatus is operable to move the object into and away from the printing region; an inkjet printhead having a plurality of nozzles spaced apart at a nozzle pitch in a nozzle row direction, the printing apparatus being operative to effect relative movement of the printhead and the object, during printing, with a rotational component about an axis of rotation and with a linear component, in which the linear component is at least partially in a direction substantially parallel with the axis of rotation and wherein the nozzle pitch of the printhead is greater than the grid pitch of the image in the nozzle row direction; and wherein the printhead and the handing apparatus are operative to move with respect to each other and the handing apparatus is further operative to rotate the object with a variable angular velocity so that a printing surface of the object that is at non-constant radius with respect to the axis of rotation passes a nozzle of the printhead with a substantially constant linear velocity.