Abstract: Method and apparatus for determining jet fuel density. A microprocessor monitors the temperature, velocity of sound and dielectric constant of a jet fuel. The microprocessor determines the type of jet fuel and the density of the fuel using data from jet fuel samples of a known density and a least-squares-fit of the test data.

Abstract: A sensor for measuring fluid concentrations or the temperature of body. A fiber-optic catheter having a fluorometric sensor attached at a distal end is excited by a light source outside the body. The sensor fluoresces with an intensity or with a lifetime related to the concentration of the fluid or the temperature. The catheter has one light pipe for exciting the sensor and a second light pipe for generating a reference signal to calibrate signals from the fluorometric sensor. One embodiment has two sensors that fluoresce with different intensities and lifetimes to simultaneously give information about both the temperature and the fluid concentration.

Abstract: An ink jet droplet exciter for generating pressure waves in a droplet generator. The preferred exciter is a composite made of PZT, Pb (Zr:Ti) O.sub.3, and a polyethylene supporting material. The mean diameter of the PZT particles is 7 mils and the entire exciter thickness is between 10 and 12 mils. The composite is pliable and can be made in sheets of a large enough area to provide droplet excitation for a multiple nozzle generator.

Abstract: An ink jet printer having a drop generator for directing streams of ink droplets through deflection electrodes so that droplets travel to either a gutter or to selected regions on a printing medium. The gutter is constructed of a first low surface energy material such as parylene coated to a high surface energy material such as stainless steel. Only a portion of the steel is coated so that a boundary between high and low surface energy material is contacted by ink after it strikes the gutter. This boundary attracts the ink away from the gutter entrance due to capillary action and in a preferred embodiment is also aided by the force of gravity due to the orientation of the gutter.

Abstract: An electro-optic wave guide substrate for both intensity modulating and continuously deflecting an incident laser beam. A first set of electrodes for intensity modulating the beam include substantially parallel, periodically interdigital conductors affixed to a substrate surface and coupled to a controlled voltage source. A second set of electrodes for beam deflecting have non-parallel conductors affixed to the same substrate and are also coupled to a controlled voltage. By controlling the voltage applied to the second set of electrodes the beam can be continuously deflected through a controlled angle to facet track a rapidly rotating multi-faceted mirror of a raster output scanner. The substrate is fabricated using a new technique whereby the atmosphere in which the waveguiding surface is diffused is controlled. In particular, the diffusion is done in a heated oxygen environment having an elevated moisture content.

Abstract: An improved ink jet marking architecture for enhancing ink droplet placing accuracy. The improved architecture combines a bipolar scanning arrangement with a drop interlace scheme. The preferred marking apparatus comprises an array of ink jet column generators which direct ink droplets to first a charging region and then through a deflection region. The droplets are charged either negatively or positively depending on a desired droplet trajectory; thus the bipolar designation. The deflection region has an electric field strength slightly less than the breakdown field strength of air for the environment in which the apparatus is to operate. The high field strength reduces the charge which must be applied to the droplets and therefore minimizes the drop to drop coulomb interaction. The interlace strategy causes sequential drops from a given generator to be printed in non-sequential locations on the paper.

Abstract: An ink jet printer having improved droplet sensing apparatus for calibrating the printer. The improved apparatus defines a number of sensing sites each having first and second light sources for directing light signals through a sensing zone and a single fiber optic light pipe leading away from the sensing zone to circuitry for detecting the presence of ink droplets in that sensing zone. The preferred apparatus includes two light emitting diodes, each of which generate visible light signals of different wavelengths. These two light signals are received by an output light pipe and travel together along the right pipe to means for detecting the intensity of the two signals and determining droplet positioning in the sensing zone as a function of the two intensities. One apparatus for differentiating between the two light intensities comprises first and second photo detectors which respond to the wavelength light generated by the two light sources.

Abstract: A method for fabricating an ink jet droplet generator. According to the disclosed technique, a metallic body is first machined to define one or more ink receiving cavities and to further define an intended nozzle surface. Resist material is applied to the nozzle surface at the intended ink nozzle positions and a thin metallic plating formed on the surface. The resist and body are then etched to form one or more passageways from the ink cavities past the regions formerly occupied by the resist. These passageways form the generator nozzles.

Abstract: A visible light projection device for producing an image on a screen in a variety of angular orientations and sizes. The device includes two servo controlled prisms rotatable about two transverse axes. The prisms serve to direct an input image to a zoom lens for reprojection of the image on a suitable screen in a variety of angular positions and image sizes.