Abstract: A high-resolution ink jet printer includes a drum supported for rotation about an axis, substrate positioning means for positioning a substrate sheet on the surface of the drum to receive a printed image, carriage means movable parallel to the drum axis, printhead means supported on the carriage means and having at least one array of orifices disposed in spaced relation to the surface of the drum for projecting ink drops onto a substrate sheet carried by the drum, drive means for driving the carriage parallel to the axis of the drum, encoder means providing a train of signals at a rate dependent upon the rate of rotation of the drum, and control means for controlling the projection of the ink drops from the printhead means at a rate that depends on the rate of signals received by the control means.

Abstract: A high resolution ink jet printer includes a rotating drum and a pair of ink jet heads scanned along a substrate carried by the drum in a direction parallel to the axis of the drum. The heads are driven by a lead screw coupled to the drum drive shaft and a control unit controls the rate of drop ejection from the printheads at a rate corresponding to the rate of encoder signals received from an encoder coupled to the drum drive draft. One printhead receives and ejects drops of black, magenta, cyan and yellow high-density inks and the other printhead ejects drops of black, magenta and cyan low-density inks along with another ink which may be a different color or black ink of a different density. High resolution and high print quality are assured by accurate control of the distance between the drum support shaft and the drum surface and also between the drum support shaft and a carriage support rail on which the printhead is supported as it moves adjacent to the drum surface.

Abstract: Apparatus for precisely positioning one or more of the work stations of a document printer/copier relative to an internal drum, including a first member, attached to either a work station or the internal drum, having two sections, each section having a reference surface forming an angle therebetween, an actuator for changing the included angle between the first reference surface and second reference surface, thus enabling the included angle to be increased or decreased, and a second member having a reference surface that mates with the pair of reference surfaces, associated with the other of the work station or the internal drum, so as to accurately adjust the work station relative to the internal drum dependent upon the included angle of the first reference surface and second reference surface.

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 ink jet printing system described in the specification, a hot melt ink jet printhead having two ink reservoirs is coupled through an ink supply line to a remote hot melt ink supply and a temperature controller is arranged to control the temperatures of the ink in the remote ink supply, the supply line, the ink reservoirs in the printhead and passages leading from the reservoirs to the ink jet orifices at selected temperature levels to inhibit high-temperature degradation of the ink while permitting the ink to be jetted at the desired jetting temperature. In addition, a pressure control system controls the pressure of the ink in the printhead at one or more selected levels to permit the printhead to be used at different orientations and to permit purging of air bubbles and contaminants from the orifice passageways and to supply a relatively high vacuum to a deaerator in the printhead to extract dissolved air from the ink.

Abstract: In the ink jet printing system described in the specification, a hot melt ink jet printhead having two ink reservoirs is coupled through an ink supply line to a remote hot melt ink supply and a temperature controller is arranged to control the temperatures of the ink in the remote ink supply, the supply line, the ink reservoirs in the printhead and passages leading from the reservoirs to the ink jet orifices at selected temperature levels to inhibit high-temperature degradation of the ink while permitting the ink to be jetted at the desired jetting temperature. In addition, a pressure control system controls the pressure of the ink in the printhead at one or more selected levels to permit the printhead to be used at different orientations and to permit purging of air bubbles and contaminants from the orifice passageways and to supply a relatively high vacuum to a deaerator in the printhead to extract dissolved air from the ink.

Abstract: 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.

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 representative ink supply system described in the specification, continuous circulation of ink in an ink jet head is accomplished by providing two reservoirs connected to each ink jet orifice through corresponding passages so that ink flows continuously from a high-level reservoir past the orifice to a low-level reservoir. The difference between the levels of ink in the reservoirs is maintained relatively constant by inertial pumping during reciprocal motion of the ink jet head or by pressure transfer of ink from one reservoir to the other reservoir. Cross-flow purging of air or debris from the ink jet head is effected by covering the ink jet orifices and applying air pressure to one reservoir to cause ink and any trapped air or debris to flow from the head to the other reservoir. A pump responsive to reciprocal motion of the ink jet head generates a positive air pressure which is applied during purging and a negative air pressure which is applied to a deaerator for removing dissolved air from the ink.

Abstract: In the particular embodiments of the invention described in the specification, a transparency includes a transparent substrate made of a polyester material, a colored ink pattern disposed on one surface of the transparent substrate in the form of three-dimensional ink spots having curved surfaces, and spots of a colorless ink made of a material which has an index of refraction approximately the same as that of the colored ink spots deposited in overlapping relation to colored ink spots as to reduce the dispersion of light by those ink spots. In one embodiment, the colorless ink spots are located in regions having no colored ink spots and in another embodiment the colorless ink spreads to a greater extent than the colored ink.

Abstract: In the embodiment of the hot melt ink supply unit described in the specification, a block of solid hot melt ink has a peripheral surface formed with a key configuration and a handle is removably connected to the block by a threaded projection. After insertion of the block into a correspondingly keyed opening in a heated reservoir, the handle is turned to separate the handle portion from the block of solid ink. A container provided with a removable seal encloses the block of solid ink and handle to protect the ink from contamination.

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 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.

Abstract: In the particular embodiments described in the specification, a hot melt ink jet system includes a temperature-controlled platen provided with a heater and with 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 a substrate on the platen which receives the ink at a temperature which provides a desired spot size without causing print-through. In certain embodiments, the substrate temperature is from about 20.degree. C. above to about 20.degree. C. below the melting point of the ink and is determined by subtracting half the difference between the jetting temperature and the temperature at which the ink has a viscosity of about 200-300 cp from the latter temperature.

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 embodiment of the hot melt ink supply unit described in the specification, a block of solid hot melt ink has a peripheral surface formed with a key configuration and a handle is removably connected to the block by a threaded projection. After insertion of the block into a correspondingly keyed opening in a heated reservoir, the handle is turned to separate the handle portion from the block of solid ink. A container provided with a removable seal encloses the block of solid ink and handle to protect the ink from contamination.

Abstract: In the particular embodiment of an ink deaerator described in the specification, an elongated ink path leading to an ink jet head is formed between two permeable membranes. The membranes are backed by air plenums which contain support members to hold the membranes in position. Reduced pressure is applied to the plenums to extract dissolved air from the ink in the ink path. Increased pressure can also be applied to the plenums to eject ink from the ink jet head for purging. Within the ink jet head ink is circulated convectively from the orifice to the deaerating path even when the jet is not jetting ink.

Abstract: .[.The invention provides a.]. .Iadd.A .Iaddend.scanner system .[.which.]. in one embodiment includes only a single moving part in the document path, namley a drive roll, which serves not only to move the document through the system, but also to provide a backing against which the document is pushed while a proximate region thereof is being scanned. .[.The invention in an.]. .Iadd.An .Iaddend.embodiment also provides an opto-mechanical assembly that is shock-mounted to the frame of the system at only three-spaced apart locations, so that the assembly tends to be isolated from vibration and torsional forces.