Abstract: A media sheet handling system and a method of duplex printing are disclosed wherein a media sheet is imaged with a phase change ink on both sides of the media sheet without smudging or remelting the images and the media sheet is partially exited from the printer into a media output tray and then is drawn back into the printer along a duplex path of travel that automatically reverses the media sheet so that the trailing edge becomes the leading edge during the imaging of the second side of the media sheet. The stiffness of the media sheet facilitates the media sheet moving above and beyond a stationary media path diverter prior to reversing its direction of travel along and passing along the duplex path of travel back to the imaging station.

Abstract: A method of printing with phase change ink on an ink jet printer that contains multiple levels of black gray scale ink and a clear or slightly tinted wax ink base and which is applied to the roughened surface of an adhesion promoting coating applied to a transparent substrate is disclosed. The adhesion promoting coating has a surface roughness of greater than about 0.5 micrometers and contains a binder and an inorganic particulate material.

Abstract: Reactive ink compositions of the present invention utilize at least two reactive components, a base ink component and a curing component, that are applied to a receiving substrate separately. The base ink component includes an ink carrier, a compatible colorant, and a cross-linkable constituent, and the curing component is a cross-linking agent. Upon exposure of the base ink component to the curing component, at least a portion of the ink is cross-linked to provide a printed image that is durable and abrasion-resistant.

Abstract: A digital halftone pattern geometry adapted not to the characteristics of variable dot size printing presses but to the operating characteristics of the printer itself achieves a high degree of image quality. The techniques for creating the halftone pattern geometry include linear spot growth to provide uniform darkening and the use of a super-cell structure to maximize the number of tint or gray scale levels. A preferred super-cell structure is of hexagonal dispersed-dot form to reduce low frequency artifacts by spreading them over a greater number of frequencies. Hexagonal centered super-cells also distribute row and column artifacts along three axes of symmetry instead of two. The super-cell structure gives sharp edges and a greater amount of edge area available to manipulate when the super-cells are tessellated to form an image. This halftone cell arrangement is especially suited to thermal transfer printers, which print linear rows and form good rectangular shapes.

Abstract: Colored waxes are made by reacting selected nucleophiles, including alcohol containing colorants with an isocyanate are disclosed. A phase change ink is made by blending the colored wax with a clear ink carrier composition. The clear ink carrier composition can be a fatty amide-based material and/or a combination of isocyanate-derived resins in which the order of addition of the isocyanate and the different nucleophiles can tailor the distribution of di-urethane, mixed urethane/urea, and/or di-urea molecules in the final resin product. The colored wax materials are useful as ingredients with phase change ink carrier compositions to make phase change ink jet inks.

Abstract: A phase change ink composition is disclosed wherein the ink composition utilizes colorant in combination with a selected phase change ink carrier composition containing at least one hydroxy-functional fatty amide compound.

Abstract: A duty cycle based AC power control method reduces objectionable voltage fluctuations at a frequency that causes "flicker" by shifting the frequency of actuations of controlled devices to frequencies significantly greater than and/or less than the flicker sensitive frequency. The frequency of actuations may be redistributed (1) by segmenting the devices to provide approximately equal power requirements per actuation, (2) by providing one-half cycle actuation pulses rather than one cycle actuation pulses, and/or (3) by spacing the actuations evenly over a given time period and forcing the aggregate demand to follow a slowly rising/falling envelope. The result is the minimization of power distribution at the flicker frequency.

Abstract: An improved ink stick supply assembly is provided for a solid ink color printer which reliability feeds solid ink sticks from an ink stick loading bin to ink stick melt plates which melt the ink sticks on demand and guide the molten ink into individual color ink reservoirs in the printer print head. Low ink and empty ink level sensors are provided which advise the printer operator when to replenish the ink stick supply. A low friction material and spring loaded pusher blocks facilitate travel of the inks through the ink stick feed chutes to the melt plates.

Abstract: A method of cleaning a media preheater that is positioned in the media path of a printer is disclosed. The media preheater has a fixed heater and a movable plate array biased toward the heater such that printer media passing between the plate array and the heater is compressed therebetween and heated. The preheater may be positioned upstream of a print head and downstream of a media advancing mechanism in the media path. More than one plate may be provided in the plate array to accommodate non-planarity of the heater or the printing media. The method elevates the temperature of the contact surface of the preheater to a cleaning temperature that is greater than the operating temperature and then passes a chase sheet over the surface to remove contamination from the preheater surface.

Abstract: A halftoning method characterized by two nonaligned halftone screens, one for black and the other for the subtractive primary colors cyan, magenta, and yellow, produces multi-color images on a color laser printer. The black screen is the inverse of, i.e., in reverse fill order to, the subtractive primary colors screen. The halftone pattern is a vertical line screen. In a preferred embodiment, the cells are grouped on hexagonal centers and aligned along X and Y coordinate axes. The dots are grouped in the linear direction of print medium motion. The grouping of dots reduces the effect of halftone screen misregistration, and the cell alignment in X and Y results in fewer high frequency artifacts. Inverting the black screen increases the number of possible chromatic mixed colors that include black, increases color uniformity and reduces the frequency of white "holes" in the printed images.

Abstract: Resins and waxes made by reacting selected nucleophiles, including alcohols and/or amines, with an isocyanate are disclosed. The order of addition of the isocyanate and the different nucleophiles can tailor the distribution of diurethane, mixed urethane/urea, and/or di-urea molecules in the final resin product. The isocyanate-derived resin and wax materials are useful as ingredients as phase change ink carrier compositions used to make phase change ink jet inks.

Abstract: Resins and waxes made by reacting selected nucleophiles, including alcohols and/or amines, with an isocyanate are disclosed. The order of addition of the isocyanate and the different nucleophiles can tailor the distribution of diurethane, mixed urethane/urea, and/or di-urea molecules in the final resin product. The isocyanate-derived resin and wax materials are useful as ingredients as phase change ink carrier compositions used to make phase change ink jet inks.