Three-dimensional object printing apparatus and method

Abstract

Ejection nozzles ( ) are located in a nozzle surface ( ) of an ejection head ( ). A distance (H: Ha-Hg) between each of the ejection nozzles ( ) and a printing object ( ) is obtained and compared with a permissible distance (H ) which is determined by the required level of print quality. The ejection nozzles ( ) whose distances (H) from the printing object ( ) are not more than the permissible distance (H ) are enabled for ink ejection, while the ejection nozzles ( ) whose distances (H) are greater than the permissible distance (H ) are disabled for ink ejection. The surface of a printing object ( ) is divided into a plurality of target areas ( ), each of which is then approximated by a projective plane ( ). Then, image data about a projected image ( ) which is obtained by orthogonal projection of a print image ( ) onto the projective planes ( ), is obtained from print image data about an image to be printed on the surface of the printing object ( ). According to the projected image data obtained, printing is performed on the target area ( ) while moving a ink-jet printhead ( ) in parallel with the projective planes ( ). This inhibits image degradation during printing on a three-dimensional printing object and also facilitates control of the inclination and position of the ejection head relative to the printing object, thereby permitting high-speed printing.