Abstract: A method for preparing a transparency involves application of hot melt ink to a transparent substrate to form a three-dimensional pattern with subsequent heating of the hot melt image above its melting point to change the configuration of the upper surface. In the embodiment described in the specification, a hot melt ink image on a substrate is treated in a continuous manner by moving it along a platen having a heating zone to melt drops of hot melt ink and cause them to spread on the substrate. The platen has a flat central portion and curved portions at each end with curvatures sufficient to prevent formation of cockle. At the output end of the heating zone, the substrate is moved continuously into a quenching zone where a cooling platen cools the substrate by thermal contact at a rapid rate to prevent crystallization or frosting of the hot melt ink image.

Abstract: In the particular embodiments of the invention described in the specification, the surface of a hot melt ink image in a projection transparency having curved surface portions is reoriented to provide an ink layer of substantially uniform thickness causing rectilinear transmission of light rays passing through the transparency and provide a clear, saturated projection image. Reorienting of the curved surface portion to provide a layer of uniform thickness is accomplished by burnishing, pressing with or without heating, rolling with or without heating, or heating the ink to a temperature above its melting point for a selected time such as 0.5 to 10 seconds. Preferably, the ink is cooled rapidly after remelting to reduce crystallization and frosting and thereby reduce light transmission losses in the ink.

Abstract: In the embodiment described in the specification, a hot melt ink image on a substrate is treated in a continuous manner by moving it along a platen having a heating zone to melt drops of hot melt ink and cause them to spread on the substrate. The platen has a flat central portion and curved portions at each end with curvatures sufficient to prevent formation of cockle. At the output end of the heating zone, the substrate is moved continuously into a quenching zone where a cooling platen cools the substrate by thermal contact at a rapid rate to prevent crystallization or frosting of the hot melt ink image. After the quenching zone, the substrate is moved along a surface having a reverse curvature with respect to the curved portions of the heating platen to eliminate residual curvature of the substrate resulting from the curved portions of the heating platen.

Abstract: In the embodiment described in the specification, a hot melt ink coating such as an image on a substrate is treated in a continuous manner by moving it along a platen having a heating zone to melt drops of hot melt ink and cause them to spread on the substrate. The platen has a flat central portion and curved portions at each end with curvatures sufficient to prevent formation of cockle. At the output end of the heating zone, the substrate is moved continuously into a quenching zone where a cooling platent cools the substrate by thermal contact at a rapid rate of at least 50.degree. C. per second to prevent crystallization or frosting of the hot melt ink image thereby minimizing light transmission losses. After the quenching zone, the substrate is moved along a surface having a reverse curvature with respect to the curved portions of the heating platen to eliminate residual curvature of the substrate resulting from the curved portions of the heating platen.

Abstract: In the particular embodiments of the invention described in the specification, an opaque subtractive color ink reflection print having improved color purity resulting from reduced frosting and crystallization of the ink layers is prepared by reheating the ink image to a temperature above the melting point of at least one of the inks and then quenching the image by cooling it at a rate of at least 50.degree. C. per second. In one embodiment, the ink image is produced by an ink jet head applied to a substrate supported on a platen maintained at least 20.degree. C. below the melting point of the inks to inhibit spreading of the inks into the substrate, and the image is thereafter heated to a temperature at least 20.degree. C. above the melting point of at least one of the inks for a period of 3 to 5 seconds and then quenched at a rate of 500.degree. C. per second to produce an image having less than 20% light loss resulting from scattering of light by frosting and crystallization of the ink in the layers.

Abstract: In the embodiment described in the specification, a hot melt ink image on a substrate is treated in a continuous manner by moving it along a platen having a heating zone to melt drops of hot melt ink and cause them to spread on the substrate and decrease the angle of contact of the drops with the surface of the substrate. The platen has a flat central portion and curved portions at each end with curvatures sufficient to prevent formation of cockle. At the output end of the heating zone, the substrate is moved continuously into a quenching zone where a cooling platen cools the substrate by thermal contact at a rapid rate to prevent crystallization or frosting of the hot melt ink image. After the quenching zone, the substrate is moved along a surface having a reverse curvature with respect to the curved portions of the heating platen to eliminate residual curvature of the substrate resulting from the curved portions of the heating platen.

Abstract: In the particular embodiment of the invention described in the specification, a hot melt ink print is prepared by applying the ink to a porous substrate, permitting it to solidify, and reheating the substrate and the ink to a temperature 5.degree. C. to 30.degree. C. above the melting point of the ink for 0.5 to 10 seconds. In one embodiment, the porous substrate is supported on a platen which is maintained at least 30.degree. C. below the melting point of the ink to prevent drying of the substrate and to inhibit spreading of the ink into the substrate. The subsequent reheating of the ink in a controlled manner causes the ink to penetrate to a desired extent into the substrate while preventing shrinkage or cockling of the substrate.

Abstract: An improved construction for a continuous ink jet printing system of the kind having a chamber for receiving a plurality of ink cartridges, a plurality of ink supply sub-systems for delivering ink from the cartridges to respective print heads and a plurality of ink return sub-systems for returning ink from the print heads to respective cartridges. The cartridge chamber is constructed to be substantially air-tight and the ink cartridges have a vent opening to their interior. The chamber itself is coupled to a vacuum source and the cartridges in the chamber are maintained at the chamber pressure via their vent openings. The chamber evacuating source includes a source of compressed air and a venturi devcie coupled to the housing interior and the compressed air source. The compressed air source also can be coupled, via check valves structure, to provide drying air to the print heads.

Abstract: In the particular embodiments of the invention described in the specification, a projection transparency includes a transparent substrate and an ink pattern disposed on one surface of the transparent sheet in the form of three-dimensional ink spots having curved surfaces with a radius of curvature of at least 3 mils and an angle of contact with the substrate of no more than about 25.degree.. The transparency is prepared by applying ink drops to the substrate and maintaining the ink at a temperature above its melting point for a selected time such as 0.5 to 10 seconds. Thereafter, the ink is cooled rapidly to reduce crystallization and frosting and thereby reduce light transmission losses in the ink to less than 50%.

Abstract: An improved damping system for continuous ink jet printers of the kind having: (i) a print head, including an ink cavity and an orifice plate coupled to the cavity, and (ii) an ink circulation system having an ink supply conduit to the print head cavity inlet and an ink return conduit coupled to the cavity outlet. The damping system reduces ink pressure transients within said print head means and includes: (i) a damping chamber for enclosing a gas-over-ink region that is coupled to the ink return conduit at a location proximate the print head and (ii) a printer subsystem for periodically introducing gas into said ink return conduit upstream of the damper chamber.

Abstract: The detection system includes a cartridge having a first detection port for detecting the pressure condition in the top portion of the cartridge and a second detection port and tube for detecting the pressure condition in a bottom portion of the cartridge. The cooperative printer structure couples these ports to a pressure differential sensor that signals a printer refill condition.