Patent ID: 7669946

Claim:
A printing apparatus for making colored contact lenses, comprising: (1) a securing means for holding a contact lens or a portion of a mold for making the contact lens; (2) a printer head, wherein the printer head comprises one or more nozzles each of which is capable of jetting droplets of color liquid independent of each other under control of a computer system; (3) a positioning means for precisely positioning the printer head at each of a plurality of predetermined printing positions, one at a time from a first printing position to a last printing position on a curved surface of the contact lens or the mold portion under control of the computer system; and (4) a means for converting a two-dimension color image into a set of printing control signals that control jetting of each of the nozzles at each of the predetermined printing positions on the curved surface of the contact lens or the mold portion to obtain a three dimensional color image on the curved surface, wherein each of the two-dimensional color image and the three-dimensional color image on the curved surface is represented by a matrix of discrete color dots or blended color dots or both, wherein during converting of the two-dimensional color image into the set of the printing control signals, the two-dimensional color image is converted into a three-dimensional color image by projecting the two-dimensional color image onto a hemispherical surface and the density of dots in the three-dimensional color image is kept constant by adding dots or deleting dots or both in the dot matrix of the three-dimensional color image on the curved surface of the article, wherein the positioning means is a motor assembly, wherein the motor assembly moves the contact lens or the mold portion or the printer head along a translational axis, rotates the contact lens or the mold portion or the printer head around a rotational axis that passes through the apical center of the surface of the contact lens or the mold portion in a direction normal to the surface of the contact lens or the mold portion, and tilts the contact lens or the mold portion or the printer head with respect to the rotational axis.