Abstract: A non-erasable ink-jet composition that is the admixture of (1) an aqueous colored polyurethane dispersion that is the reaction product of (a) a colored urethane prepolymer that is the catalyzed reaction product of at least one polyol; at least one polyisocyanate; at least one internal surfactant; and at least one reactive colorant; wherein the ratio of internal surfactant to polyol and the ratio of NCO groups to total OH groups are predetermined stoichiometric equivalent molar ratios; (b) at least one neutralizing agent; (c) a first aqueous dispersing medium; and (d) at least one chain extender; (2) a second aqueous medium; and (3) at least one humectant; wherein the ink composition has a jettable viscosity from about 1 to about 20 centipoise at about 10.degree. C. to about 45.degree. C.

Abstract: A media preheater positioned in the media path of a printer and having a fixed heater and a movable plate array biased toward the heater such that printing media passing between the heater and the plate array 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 medium. The plate array may be a thermally massive element that contacts the heater when no media is present, thereby permitting the medium to be heated from both sides.

Abstract: A flexible bar connected to an actuator is suspended within an ink reservoir. The bar is preferably mounted in a cantilever or free-standing mode and vibrates in response to signals from the actuator. When the actuator signals are discontinued the bar continues to vibrate and causes the actuator to generate signals that are analyzed to determine the level of ink in the reservoir.

Abstract: An ink jet (10, 200) provides high-resolution gray scale printing or switchable resolution printing by providing PZT drive waveforms (100, 110, 120, 360, 370), each having a spectral energy distribution that excites a modal resonance of ink in an ink jet print head orifice (14, 208). By selecting the particular drive waveform with selectable energy inputs that concentrates spectral energy at frequencies associated with a desired oscillation mode and that suppresses energy at the other oscillation modes, an ink drop (170, 180, 190, 210) is ejected that has a diameter proportional to a center excursion size of the selected meniscus surface oscillation mode. The center excursion size of high order oscillation modes is substantially smaller than the orifice diameter, thereby causing ejection of ink drops smaller than the orifice diameter. Conventional orifice manufacturing techniques may be used because a specific orifice diameter is not required.

Abstract: A method of printing an image onto a substrate includes the steps of determining a difference in intended color intensity between a first pixel and a second pixel; adjusting the intended color intensity of the first pixel based on the determined difference; and depositing a colorant onto the substrate at the first pixel at the adjusted intended intensity, so as to enhance the appearance of the image on the substrate. The current system has particular utility in enhancing the appearance of fine images such as one pixel wide, vertical and diagonal lines in a printing system which utilizes printhead heating elements that are larger in the vertical direction than in the horizontal direction.

Abstract: A compact ink jet print head has cross-sectionally tapered ink manifolds (16) for supplying ink to ink supply channels (18) leading to the acoustically driven ink pressure chambers (22). An array of closely spaced nozzles (14) which are supplied with ink from the densely packed ink pressure chambers by way of offset channels (71). The tapered manifolds, ink supply channels, pressure chambers, and offset channels are designed to provide uniform operating characteristics among the ink jet nozzles of the array. To enhance the packing density of the pressure chambers, the ink supply channels leading to the pressure chambers and offset channels are positioned in planes between the pressure chambers and nozzles. The tapered ink supply manifolds enhance purging of contaminants or bubbles from the print head by providing uniform ink flow rates (97, 97') along the entire length of the manifolds.

Abstract: A phase-locked loop circuit comprises a VCO and a ramp generator. The ramp generator has an output connected to a control terminal of the VCO. A center frequency control loop is connected between a signal output terminal of the VCO and a first ramp control input of the ramp generator and a spread spectrum control loop is connected between the signal output terminal of the VCO and a second ramp control input of the ramp generator. The signals applied to the ramp control inputs of the ramp generator by the two control loops control respective characteristics of a periodic voltage ramp signal that is generated by the ramp generator at its signal output terminal.

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 system for printing an image onto a substrate includes a print controller that determines a difference in intended color intensity between a first pixel and a second pixel; adjusts the intended color intensity of the first pixel based on the determined difference; and deposits a colorant onto the substrate at the first pixel at the adjusted intended intensity, so as to enhance the appearance of the image on the substrate. The current system has particular utility in enhancing the appearance of fine images such as one pixel wide, vertical and diagonal lines in a printing system which utilizes printhead heating elements that are larger in the vertical direction than in the horizontal direction.

Abstract: An improved media-width phase-change ink-jet print had (102) maintains a uniform temperature across its width to produce consistent drop mass and uniform print quality. The print head uses a heater (120) including two separately controlled, overlapping heating zones (154). The heating zones produce heat gradients (170, 172) that have maximum outputs toward opposing edges (168a, 168b) of the print head and are controlled in response to thermistors (138s, 168b) positioned at the corresponding edges. The two heating zones together produce a linear heat gradient (180) across the print heat to compensate for uneven head-to-drum spacing (166) and other unsymmetrical thermal loads on the print head. The improved print head also includes baffles (192) that reduce air flow between the head and the attached reservoir (118), and thermal breaks (218) that insulate the section (220) of the head that includes the jets from the thermal gradients at the edges of the print head.

Abstract: Improved color ink-jet printing is accomplished by an ink-jet nozzle array configuration (32, 110) which has an odd number of nozzles (34) that are uniformly spaced apart by two line widths (2 V) such that naturally interlaced printing is accomplished when a print head (54) employing the nozzle array configuration is moved in uniformly stepped intervals. A color ink-jet print head employing the array configuration further employs multiple horizontally spaced apart instances (30) of the array in which each array ejects a particular color of ink, and the nozzles of each array are aligned in the direction of scanning to eject ink toward a common band of lines.

Abstract: An image transfer ink-jet printer employs an image receiving drum that rotates relative to an ink-jet array print head spanning the full width of the drum. A print head positioner moves the print head in precise increments to position adjacent scan lines of ink drops. Without affecting the overall scale of the image, adjacent pairs of scan lines are spaced at distances less than one nominal pixel width. Pairings within the range of 0.2 to 0.5 pixel widths are used, with optimal spacing at 0.35 pixel widths.

Abstract: A phase change ink composition is disclosed wherein the ink composition utilizes polymeric dyes in combination with a selected phase change ink carrier composition.