Spectra, Inc.

Xerox Corporation

Robert R Schaffer

Paul A Hoisington

Charles W Spehrley, Jr

Linda T Creagh

Lawrence R Young

Bruce A Paulson

Kenneth H Fischbeck

Steven F Fulton

Edward Russell Moynihan

Michael A Malachowski

Steven J Fulton

Dean Thomas

Michelle Anne Remus

An apparatus for advancing a sheet from a moving imaging member having an unfused image after transfer of the image to the sheet. After the image is transferred to the sheet, the sheet is advanced by a transport to a fuser. The transport has low impedance, high air flow to draw the sheet toward the transport for acquisition. As the sheet is moved across the transport, an increased air flow impedance causes a low vacuum pressure in the transport to provide a low drive force that minimizes quality and motion disturbances on the sheet. The low drive force exerted on the sleet is lower than a holding force of the sheet to the moving imaging member thus causing the sheet to slide on the transport.

High air flow low pressure prefuser transport

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.

Post-processing of colored hot melt ink images

In the representative embodiments of the invention described in the specification, an ink jet head has a series of aligned arrays of ink jet orifices arranged to project drops of different colored inks in sequence to the same location on a substrate during each scan of the ink jet head adjacent to the substrate. The spacing of the orifices in each aligned array and the speed of the ink jet head during the scanning are arranged so that all the ink drops applied at the same location on the substrate are applied in a time period of no more than about 100 milliseconds and preferably no more than 50 milliseconds. Moreover, to avoid banding the lines produced by successive scans of the head are interlaced so as to produce a periodic frequency of no more than about four lines per millimeter.

Bidirectional hot melt ink jet printing

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.

Remelting of printed hot melt ink images

In the representative embodiments of an ink jet array described in the specification, a plurality of ink sources is arranged to provide different inks to selected orifices and a linear array of ink jet orifices is supplied with ink from pressure chambers alternately disposed on opposite sides of the array to permit close spacing of the ink jet orifice and adjacent pairs of orifices in the array receive ink from the same ink source. At the end opposite from the ink jet orifice, each pressure chamber having a compliant wall communicates with a low acoustic impedance chamber to reflect negative pressure pulses from the pressure chamber back through the chamber as positive pulses to reinforce positive pulses applied to the pressure chamber and to prevent pressure pulses from being transmitted to the ink supply.

Ink jet array

In the particular embodiments of the invention described in the specification, a transparency includes a transparent substrate made of a polyester material, an ink pattern disposed on one surface of the transparent sheet in the form of three-dimensional ink spots having curved surfaces and a transparent layer convering the ink spots which has an index of refraction approximately the same as that of the ink spots. The transparent layer is applied to the substrate and the ink spots in the form of a liquid coating which wets the surfaces of the substrate and ink spots and spreads over them to produce a transparent layer having a maximum deviation of about 20 degrees from a plane parallel to the substrate.

Hot melt ink transparency

An apparatus in which a sheet is advanced into registration with information developed on a moving member. Spaced belts having a sheet gripper secured thereto move the sheet in a recirculating path of movement. The belts move at a first velocity during registration of the sheet with the information on the moving member and at a second velocity during non-registration of the sheet with the information on the moving member.

Sheet transport

In the representative embodiments of an ink jet array described in the specification, a linear array of ink jet orifices is supplied with ink from pressure chambers alternately disposed on opposite sides of the array to permit close spacing of the ink jet orifices. At the end opposite from the ink jet orifice, each pressure chamber communicates with a low acoustic impedance chamber to reflect negative pressure pulses from the pressure chamber back through the chamber as positive pulses and to prevent pressure pulses from being transmitted to the ink supply. In addition, a high-impedance passage between the low acoustic impedance chamber associated with one pressure chamber and the pressure chamber for the adjacent ink jet provides a continuous flowthrough passage from the ink supply port for one ink jet to the ink supply port for an adjacent ink jet. This permits continuous circulation by thermal convection of the ink when the ink jets are not in use to prevent settling of pigment in a pigmented ink and to transport ink containing dissolved air from the region of the ink jet orifice to a deaeration passage.

A transparency includes a transparent substrate such as a polyester material, an ink pattern disposed on one surface of the transparent sheet in the form of three-dimensional ink spots having curved surfaces and a transparent layer covering the ink spots which has an index of refraction approximately the same as that of the ink spots. The transparent layer is applied to the substrate and the ink spots in the form of a liquid coating which wets the surfaces of the substrate and ink spots and spreads over them to produce a transparent layer having a maximum deviation of about 20 degrees from a plane parallel to the substrate.

Method for preparing a hot melt ink transparency

In the particular embodiment described in the specification, a hot melt ink jet system includes a temperature-controlled platen provided with a heater and a thermoelectric cooler electrically connected to a heat pump and a temperature control unit for controlling the operation of the heater and the heat pump to maintain the platen temperature at a desired level. The apparatus also includes a second thermoelectric cooler to solidify hot melt ink in a selected zone more rapidly to avoid offset by a pinch roll coming in contact with the surface of the substrate to which hot melt ink has been applied. An airtight enclosure surrounding the platen is connected to a vacuum pump and has slits adjacent to the platen to hold the substrate in thermal contact with the platen.

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Canaan, NH, United States of America

Robert R Schaffer