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US 9,114,652 B1Granted
System for detecting inoperative inkjets in printheads ejecting clear ink using heated thermal substrates
AssigneeXerox Corporation
InventorWilliam H. Wayman
Life of this patent
Estimating the term…
Abstract
An apparatus detects inoperative inkjets during printing operations. The apparatus includes a supply of thermal substrate that is exposed to heat to darken the substrate. The thermal substrate is printed with materials ejected from a printhead to form a test pattern. The contrast between the ejected materials and the exposed thermal substrate are imaged by an optical sensor to generate image data that are analyzed to identify inoperative inkjets.
Claims16
A printer comprising:
- a printhead configured with a plurality of inkjets to eject material;
- a supply of thermal substrate configured to move thermal substrate to a position opposite the printhead to receive material ejected from the printhead;
- an optical sensor configured to generate electrical signals corresponding to an optical density of a location on the thermal substrate;
- an actuator operatively connected to the optical sensor to move the optical sensor to a position opposite the thermal substrate onto which material has been ejected;
- a heater configured to expose a length of thermal substrate to heat;
- and
- a controller operatively connected to both actuators, the optical sensor, the heater, and the printhead, the controller being configured to operate the printhead to eject a predetermined number of material drops from each inkjet onto the thermal substrate to enable the predetermined number of material drops to form a test dot for each inkjet on the thermal substrate, to operate the heater to darken the length of thermal substrate exposed to heat, to operate the actuator to move the optical sensor to a position opposite the thermal substrate to generate image data of the substrate and the test dots on the substrate, and to identify inoperative inkjets in the printhead with reference to the data received from the optical sensor that corresponds to optical densities of the thermal substrate at a plurality of locations on the thermal substrate.
4 more elements
An apparatus comprising:
- a supply of thermal substrate;
- an optical sensor configured to generate electrical signals data corresponding to an area of material drops on the substrate;
- an actuator operatively connected to the optical sensor to move the optical sensor to a position opposite the thermal substrate onto which material has been ejected;
- a heater configured to expose a length of thermal substrate to heat;
- and
- a controller operatively connected to the actuator, the optical sensor, and the heater, the controller being configured to operate the heater to darken the length of thermal substrate exposed to heat after inkjets in a printhead have been operated to eject a predetermined number of material drops from each inkjet onto the thermal substrate to enable the predetermined number of material drops to form a test dot for each inkjet on the thermal substrate, to operate the actuator to the optical sensor to a position opposite the thermal substrate, and to identify inoperative inkjets in the printhead with reference to the data received from the optical sensor that corresponds to optical densities of the thermal substrate at a plurality of locations on the thermal substrate.
3 more elements
Dependencies are inferred from the claim text.