System For Detecting Inoperative Inkjets In Three-Dimensional Object Printing Using An Optical Sensor And Reversible Thermal Substrates

摘要

An apparatus detects inoperative inkjets during printing of three-dimensional objects. The apparatus includes a reversible thermal substrate that changes optical density in areas where material drops are ejected onto the substrate. An optical sensor generates image data of the substrate after material drops are ejected onto the substrate and these image data are analyzed to identify inoperative inkjets.

主权项

1. A printer comprising:
a printhead configured with inkjets to eject drops of material; a thermal substrate configured to move to a position opposite the printhead to receive drops ejected from the printhead; an optical sensor configured to generate data corresponding to the drops on the thermal substrate; a transport configured to move the substrate to a position opposite the optical sensor to enable the optical sensor to generate image data of the drops on the thermal substrate; and a controller operatively connected to the transport, the optical sensor, and the printhead, the controller being configured to operate the printhead to eject a predetermined number of drops from each inkjet onto the thermal substrate while the thermal substrate remains stationary at the position opposite the printhead to enable the predetermined number of drops to form a test dot for each inkjet on the thermal substrate, to operate the optical sensor to generate image data of the thermal substrate, and to identify inoperative inkjets in the printhead with reference to the image data received from the optical sensor that corresponds to the test dots on the thermal substrate.