System for detecting inoperative inkjets in three-dimensional object printing using a test pattern and an ultrasonic sensor

摘要

A printer detects inoperative inkjets during printing of three dimensional objects. The printer includes a substrate onto which a printhead ejects building and support material in a test pattern. An ultrasonic sensor scans the substrate on the unprinted side and measures thicknesses at a plurality of locations on the substrate. The thickness measurements are used to identify inoperative inkjets in the printhead and the printing of an object can be suspended to take remedial action with regard to the printhead before formation of the object is completed.

主权项

1. A printer for forming objects comprising:
a substrate having a surface; a printhead configured to eject material through inkjets in the printhead onto the surface of the substrate; at least one ultrasonic sensor, the ultrasonic sensor being configured to generate an electrical signal corresponding to a thickness of the substrate and material opposite the at least one ultrasonic sensor; and a controller operatively connected to the printhead, and the at least one ultrasonic sensor, the controller being configured to operate the printhead to eject material onto the surface of the substrate with reference to a predetermined pattern, to receive the signal generated by the at least one ultrasonic sensor, and to detect inoperative inkjets in the printhead with reference to the signal received from the at least one ultrasonic sensor and the predetermined pattern.