US 11,685,157 B2Granted

Upwards jetting digital printing platform

AssigneeElectronics for Imaging, Inc.

InventorsEduardo Bueno Espinal, Juan Escudero Gonzalez

Life of this patent

Estimating the term…

Loading patent…

Abstract

A printing platform includes a printing engine with one or more printheads arranged such that the ink drops are jetted vertically upwards against the action of gravity; and a substrate transportation system where the normal to the surface in contact with the substrate is parallel and with opposite direction to the travelling direction of the jetted ink drops. It is necessary to counteract the weight of the substrate during the printing process to avoid it from falling under the action of gravity. This is achieved through any of a mechanical element that interferes with the falling of the substrate and that keeps it in place; or a system that generates adhesion forces between the element that transmits the motion to the substrate, typically a conveyor belt, and the substrate through the action of electrostatic forces, an air pressure differential between both faces of the substrate, or any other suitable mechanism.

Claims23

Dependent claims

An apparatus, comprising:

a digital printing engine having one or more printheads arranged to jet ink drops vertically upwards to a downward facing printing surface of a sheet against the action of gravity;
and
a sheet transportation system where normal to a surface thereof that is in contact with each sheet is parallel, and with opposite direction, to the traveling direction of the jetted ink drops, said sheet transportation system conveying said downward facing printing surface of said sheet past said digital printing engine, wherein said digital printing engine forms an image on said downward facing printing surface of said sheet by jetting said ink drops vertically upwards thereto;
wherein said one or more printheads comprise:
a modification of any of the printhead, ink delivery system operating conditions, and substrate properties to ensure that the drop ejection process and deposition takes place against the action of gravity,
wherein the modification comprises any of the following aspects:
adjustments to ink delivery system setpoints that set ink temperature and viscosity, pressure within the one or more printheads, and a flow rate across the one or more printheads,
adjustments to a driving voltage signal that excites printhead actuators to effect ink drop ejection, and
adjustments to surface properties of the sheet;
and
wherein the adjustments achieve an optimal convex meniscus shape by modifying ink pressure at a meniscus at a nozzle of the printhead, wherein the ink delivery system setpoints are modified to make pressure at the meniscus slightly above atmospheric one, thereby counteracting an effect of gravity and ensuring optimal meniscus shape for drop formation.

8 more elements

A digital printer for printing on individual sheets having a downward facing printing surface, the digital printer comprising:

a digital print engine comprising one or more printheads arranged to jet ink drops vertically upwards to said downward facing printing surface of a sheet against the action of gravity;
wherein said print engine is configured to ensure that a drop ejection process and deposition takes place against the action of gravity;
wherein said configuring is performed with respect to any of the impact of gravity on an ink meniscus at nozzles of the one or more printheads, the effect of gravity on ink drop formation, the effect of gravity on a trajectory of the jetted ink drops, and the interaction of the jetted ink drops with the sheet upon landing on the sheet;
and
wherein said configuring comprises any of:
adjustments to ink delivery system setpoints that set ink temperature and viscosity, pressure within the one or more printheads, and a flow rate across the one or more printheads;
adjustments to a driving voltage signal that excites printhead actuators to effect ink drop ejection;
and
adjustments to surface properties of the sheet;
wherein said adjustments achieve an optimal convex meniscus shape by modifying ink pressure at the ink meniscus, wherein ink delivery system setpoints are modified to make pressure at the ink meniscus slightly above atmospheric one, thereby counteracting an effect of gravity and ensuring optimal meniscus shape for drop formation;
and
a sheet transportation system where normal to a surface thereof that is in contact with each sheet is parallel, and with opposite direction, to the traveling direction of the jetted ink drops, said sheet transportation system conveying said downward facing printing surface of said sheet past said digital printing engine, wherein said digital printing engine forms an image on said downward facing printing surface of said sheet by jetting said ink drops vertically upwards thereto.

9 more elements

A method for printing on individual sheets having a downward facing printing surface, comprising:

in a digital print engine, arranging one or more printheads to jet ink drops vertically upwards to said downward facing printing surface of a sheet against the action of gravity;
configuring said digital print engine to ensure that a drop ejection process and deposition takes place against the action of gravity;
performing said configuring with respect to any of the impact of gravity on an ink meniscus at nozzles of the one or more printheads, the effect of gravity on ink drop formation, the effect of gravity on a trajectory of the jetted ink drops, and the interaction of the ink drops with the sheet upon landing on the sheet;
and
wherein said configuring comprises any of:
adjusting ink delivery system setpoints that set ink temperature and viscosity, pressure within the one or more printheads, and a flow rate across the one or more printheads;
adjusting a driving voltage signal that excites printhead actuators to effect ink drop ejection;
and
adjusting surface properties of the sheet;
providing a sheet transportation system where normal to a surface thereof that is in contact with each sheet is parallel, and with opposite direction, to the traveling direction of the jetted ink drops, said sheet transportation system conveying said downward facing printing surface of said sheet past said digital printing engine, wherein said digital printing engine forms an image on said downward facing printing surface of said sheet by jetting said ink drops vertically upwards thereto;
and
achieving an optimal convex meniscus shape by modifying ink pressure at the ink meniscus, wherein ink delivery system setpoints are modified to make pressure at the ink meniscus slightly above atmospheric one, thereby counteracting an effect of gravity and ensuring optimal meniscus shape for drop formation.

9 more elements

Dependencies are inferred from the claim text.