| 主权项 |
1. A printer for forming objects comprising:
a rotating member having a surface layer and an edge along a perimeter of the surface layer, the surface layer having a refractive index in a range of about 1.4 to about 1.8; a printhead configured to eject material onto the surface layer of the rotating member, the material ejected by the printhead having a refractive index in a range of about 1.3 to about 1.5; a light source positioned to direct light into the edge of the surface layer of the rotating member; an optical sensor positioned to receive light emitted by the surface layer of the rotating member, the optical sensor being configured to generate image data corresponding to the surface layer of the rotating member; and a controller operatively connected to the printhead, the light source and the optical sensor, the controller being configured to operate the printhead to eject material onto the surface layer of the rotating member with reference to a predetermined pattern, to activate the light source selectively, to receive image data generated by the optical sensor while the light source is directing light into the edge of the rotating member, and to detect inoperable inkjets in the printhead with reference to the received image data and the predetermined pattern. |
