Abstract: Liquid sensing apparatuses and liquid sensing methods are described. In some embodiments, a liquid sensing apparatus includes a magnetic element; a source magnetic field, which produces on the magnetic element a magnetic force with a component that opposes a gravitational force on the magnetic element; and a structure configured to prevent rotation of the magnetic moment of the magnetic element relative to the magnetic field, e.g., so that the magnetic force remains greater than the gravitational force. The apparatus is capable of sensing the level of a liquid using a combination of magnetic force and buoyancy force.

Abstract: This invention features a hot melt ink composition. The composition includes a vehicle; a pigment having a modifying group on a surface of the pigment; and a polymeric dispersant including a group which associates with the modified surface and a backbone which is miscible with the vehicle.

Abstract: A technique for marking pixels on workpieces by routing a scanned beam to different marking stations to mark individual pixels on the workpieces. A diffractive scan lens focuses the beam. A mark is formed on a workpiece by producing the mark and curing the mark. Angular position of a scanning mirror in a raster scanner is determined by moving a beam, reflected from the scanner, across rulings on an optical element during scanning. A print head for printing spots on a surface of a workpiece has a walled, internally pressurized chamber and structure for causing an inked web to conform to a contour of the chamber wall and to be pulled along the chamber wall. A print head has a compliant-walled, internally pressurized chamber. A print head has a chamber having a low-coefficient of friction coating. Two workpieces may be marked at two marking stations by two-directional scanning.

Abstract: An ink supply system for an ink jet printhead having an orifice plate with orifices includes an ink reservoir connected through a valve and a luer connection to an ink supply container and an air pump arranged to produce a vacuum in the ink reservoir to draw ink form the ink supply container into the ink reservoir. The ink reservoir has an ink sensor to detect a desired ink level in the reservoir and to detect a low ink condition along with a control unit which controls the operation of the air pump for a predetermined period established by the control unit in response to signals from the sensor. A restricted passage connects the ink reservoir to the atmosphere through a filter so that the ink in the reservoir is maintained at atmospheric pressure and the level of the ink in the reservoir is selected to provide a desired negative liquid pressure head at the orifices in the ink jet printhead.

Abstract: A hot melt ink having a water auto-dispersibility of at least 50%, methods for using this ink to provide marks having a water auto-dispersibility of at least 50%, and methods for using this ink to provide UV opaque masks are disclosed.

Abstract: A technique for marking pixels on workpieces by routing a scanned beam to different marking stations to mark individual pixels on the workpieces. A diffractive scan lens focuses the beam. A mark is formed on a workpiece by producing the mark and curing the mark. Angular position of a scanning mirror in a raster scanner is determined by moving a beam, reflected from the scanner, across rulings on an optical element during scanning. A print head for printing spots on a surface of a workpiece has a walled, internally pressurized chamber and structure for causing an inked web to conform to a contour of the chamber wall and to be pulled along the chamber wall. A print head has a compliant-walled, internally pressurized chamber. A print head has a chamber having a low-coefficient of friction coating. Two workpieces may be marked at two marking stations by two-directional scanning.

Abstract: A hot melt ink having a water auto-dispersibility of at least 50%, methods for using this ink to provide marks having a water auto-dispersibility of at least 50%, and methods for using this ink to provide UV opaque masks are disclosed.

Abstract: In the particular embodiment described in the specification, an ink jet printhead has a linear array of orifices and is adapted to be mounted in three mutually orthogonal orientations to eject ink drops from the orifices in horizontal or vertical directions. The printhead includes a reservoir for supplying ink to the orifices and the outlet from the reservoir is positioned below the level of ink in the reservoir in each of the orientations of the ink jet printhead. A reservoir vent is located above the level of the ink in each of the reservoir orientations and a U-shaped tube within the reservoir has one end connected to the vent and another end which is open to the interior of the reservoir at a location which is above the level of the ink in each of the reservoir orientations.

Abstract: Improvements are provided to improve an apparatus and method for processing a substantially constant velocity flow of a web of material, including a cutting mechanism and a web accumulator upstream of the cutter. The improvements include stopping the web by a side surface of the movable blade and configuring the accumulator dimensions and cutting speed to cause an appropriate level of force between the upstream severed end of the web and the blade. Several features achieve a low cutting time and modify cutting force to cut web regions with different characteristics, such as for cutting through splices. A low inertia rotary solenoid accelerates a blade through the web and against a resilient stop. The blade bounces off of the stop to its spring-biased home position. A permanent magnet or electromagnet holds the blade in the home position as solenoid current develops. These features result in reduced noise and shorter cutting time, thereby allowing an increase in web speed.

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: A hot melt jet ink composition comprising a glycerol ester of a hydrogenated rosin and Montan wax exhibits good adhesion and resistance to offset and has substantially constant viscosity over a wide range of application temperatures.

Abstract: An ink jet composition exhibits a reduced tendency to smear upon application to a substrate. The ink composition includes a propylene glycol ether and/or a propylene glycol ether acetate, a surfactant and a colorant.

Abstract: A cup holder for rotating a doctoring ink cup includes a housing with a cup receiving chamber and a bumper extending into the chamber. The bumper contacts the ink cup to rotate it within the chamber during inking of a gravure plate. It is the relative motion of the plate and the ink cup during inking of the plate which causes the bumper to contact the ink cup. A second bumper extends into the cup receiving chamber. A method of inking a gravure plate includes inking the plate by relative motion between an ink cup and the plate, and rotating the ink cup during inking such that an edge of the ink cup in contact with the plate rotates with respect to the plate. The rotation is caused by the relative motion.

Abstract: A thermally stable ink for use in ink jet printing contains an ester amide resin, a tackifying resin, and a colorant.

Abstract: A doctoring cup particularly suited for inking non-flat plates includes a plate contacting edge with an "Ease of Flex" parameter greater than about 0.020 lb.sup.-1. Ease of Flex is defined as 1/(Mt.sup.2), where t is the thickness of the plate contacting edge and M is the flexural modulus of the material from which the cup wall defining the edge is formed. By non-flat plates is meant plates out of flat by greater than 0.0002 inches/inch. The doctoring cup can be used to ink both flat and non-flat printing plates using a doctoring pressure of less than about 300 psi.

Abstract: A transfer printing medium that includes a carrier to which is applied a curable laser-transferrable ink having one or more layers. The transfer medium is capable of converting laser energy to heat. The ink includes: (a) at least one colorant; (b) at least one polymerization initiator; and (c) at least one curable prepolymer.

Abstract: A compliant doctoring cup particularly suited for inking non-flat plates includes a body defining a cavity for containing ink and a blade with two free ends coupled to the body along a periphery of the cavity. The body of the cup defines a channel generally along a periphery of the cavity and the blade is positioned within the channel. A resilient member, for example, a liner, interfaces the blade to the body of the cup. The liner contains the ink and defines the channel.

Abstract: A printing process includes printing a liquid ink onto a substrate surface. The ink includes a vehicle and a colorant dissolved in the ink. When the ink solidifies on the substrate the colorant, which is substantially insoluble in the solidified ink, migrates and locks to the surface to provide a substantially permanent readable color to the surface.

Abstract: A device for measuring relative viscosity includes a fluid reservoir, a stirrer, and a sensing system. The stirrer has two members, with one member being more bendable than the other. When the stirrer is moving, the sensing system detects a differential bend between the members; the differential bend is related to the viscosity of a fluid in the fluid reservoir. The sensing system includes two spaced sensors which detect when magnets on the members pass the sensors. A timer provides a time lapsed between passage of one of the members past a sensor and passage of the other member past the other sensor. The time lapsed is related to the viscosity of the fluid in the fluid reservoir. A controller automatically controls the addition of a solvent to the fluid within the fluid reservoir; the addition of the solvent is dependent on the time lapsed.

Abstract: A doctoring ink cup for containing and applying ink to an engraved image on a printing plate includes a flexible doctoring cup drawn from a sheet of spring steel. The doctoring cup has rim forming a doctoring edge for wiping excess ink from the printing plate. A cup shaped stiffening member is bonded to the doctoring cup for stiffening the doctoring cup.