Patents Represented by Attorney Timothy Rex Croll
  • Patent number: 5834864
    Abstract: A specially designed, forceful, compact magnetic micro-mover includes at least one etched single crystal silicon plate having integral springs and stable, low internal stress. A structure of springs which support a rectangular plate are etched in silicon. The plate is driven by planar electromagnetic actuation. The micro-mover consists of a specific etched silicon spring in combination with a planar electromagnetic moving coil actuator that is capable of generating forces greater than 50 mN, while dissipating less than 1 W peak power. The micro-mover also includes a plate suspension system that facilitates the required plate motions and resolution, while preventing changes in plate spacing from effects such as external acceleration, temperature, humidity, and aging; and includes an actuator that appropriately moves the plates in response to electrical signals, such that there is only minimal cross-talk between axes of motion.
    Type: Grant
    Filed: September 13, 1995
    Date of Patent: November 10, 1998
    Assignee: Hewlett Packard Company
    Inventors: Victor W. Hesterman, Robert G. Walmsley, Jobst Brandt
  • Patent number: 5821019
    Abstract: A composite organic photoconductor for electrophotography is described. The composite photoconductor includes a conductive support, a charge generation layer and a particulate charge transport layer disposed between the conductive support and the charge generation layer. The charge transport layer is formed from a first colorant composition comprising a particulate pigment embedded in a polymeric matrix. The charge generation layer is formed from a second colorant composition which comprises either a pigment or a dye. The charge transport layer has an infrared absorption maximum of about 740 nm, and the charge generation layer has an infrared absorption maximum greater than about 770 nm. The composite organic photoconductor exhibits both good electrophotographic response and superior thermal stability over a range of operating conditions, and is thus useful in a number of electrophotographic processes such as those employing charging, exposing and developing operations to form images.
    Type: Grant
    Filed: April 18, 1996
    Date of Patent: October 13, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Khe C. Nguyen
  • Patent number: 5818261
    Abstract: A bus mechanism mitigates programmable device performance and power consumption issues by utilizing a small swing transmitter at the source end of an interconnect network and a high gain differential amplifier at the receiver end of the interconnect network. The signal is generated as a small swing voltage differential compared to a reference voltage and the reference voltage is set at a magnitude close to the negative power supply signal (near ground or GND). Because the performance of NMOS cross point switches with signals close to GND is very good, virtually no signal swing is lost in these NMOS cross point switches. The small swing signal voltages also significantly reduce the power dissipated when transmitting data. Transmitter pre-charge, differential amplifier equalization and a PMOS differential amplifier further enhance performance and reduce power consumption.
    Type: Grant
    Filed: August 8, 1996
    Date of Patent: October 6, 1998
    Assignee: Hewlett Packard Company
    Inventor: Frederick A. Perner
  • Patent number: 5811931
    Abstract: An edge emitter with a cap on top of a thin-film stack. The thin film stack includes a top transparent electrode, a bottom electrode, an active film between the two electrodes and an insulating film between the active film and the bottom electrode. Both the refractive indexes of the cap and the top transparent electrode are substantially matched to that of the active film to increase the amount of electroluminescent radiation propagating from the active film into the cap. The cap is thicker than the active film, and is made of a material with an attenuation to the electroluminescent radiation that is lower than that of the active film material. One side surface, the emitting side surface, of the cap is more transmissive to the electroluminescent radiation than the other side surfaces and the top surface of the cap. A significant portion of the electroluminescent radiation from the active film entering the cap is re-directed towards the emitting side surface to be radiated from the edge emitter.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: September 22, 1998
    Assignee: Hewlett Packard Company
    Inventors: Regina B. Mueller-Mach, Gerd O. Mueller
  • Patent number: 5805477
    Abstract: An arithmetic cell to be used in field programmable devices is defined in this invention. This cell will allow efficient implementations of multipliers, multipliers/accumulators and adders (addition, compare, and subtraction) in one compact cell that is a collection of circuits common to field programmable devices. This cell may be used in a flexible manner that allows full multipliers of any dimension (n*m products), adders of any length (n+m sums, compare, differences), accumulators, and registers (to hold complete results or partial products). Key elements in this invention are an application controlled multiplexer, signal routing to provide a shift function for multiplication, and a minimum collection of configuration bits and circuit elements to perform the basic arithmetic functions.
    Type: Grant
    Filed: September 26, 1996
    Date of Patent: September 8, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Frederick A. Perner
  • Patent number: 5787482
    Abstract: A disk control mechanism for controlling the operations of a movable arm disk drive. The disk control mechanism contains a disk access scheduler which accepts disk access requests having a deadline and a disk location. The disk access scheduler further consists of a queue data structure for storing the requests. The queue contains a predefinded window that contains a certain number of requests with deadlines to expire sooner than all other requests. The request that is most soon to expire, the most urgent request, is located at the head of the queue. The disk access scheduler contains logic to determine whether the most urgent request has a deadline to expire sooner than tolerated by a set threshold, and in such cases the disk access scheduler schedules for service the most urgent request prior to any other request, otherwise it scans towards the most urgent request and schedules requests with a disk location between the current arm location and the most urgent request.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: July 28, 1998
    Assignee: Hewlett-Packard Company
    Inventors: Shenze Chen, Manu Thapar
  • Patent number: 5786804
    Abstract: A method and system for tracking attitude of a device includes fixing a two-dimensional array of photosensors to the device and using the array to form a reference frame and a sample frame of images. The fields of view of the sample and reference frames largely overlap, so that there are common imaged features from frame to frame. Sample frames are correlated with the reference frame to detect differences in location of the common features. Based upon detection of correlations of features, an attitudinal signal indicative of pitch, yaw, and/or roll is generated. In the preferred embodiment, the attitudinal signal is used to manipulate a screen cursor of a display system, such as a remote interactive video system (RIVS). However, attitudinal tracking using the invention may be employed in other applications.
    Type: Grant
    Filed: October 6, 1995
    Date of Patent: July 28, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Gary B. Gordon
  • Patent number: 5779971
    Abstract: A solder drop ejector is disclosed where a current through liquid solder in a channel flows in a direction opposite to the direction of current through a fixed conductor insulated from the channel. The magnetic fields generated repulse the solder toward an orifice to eject a droplet of solder. The dielectric layer separating the fixed conductor and the solder is formed of a film. The film may be made extremely thin, such as 0.1 microns, so that the necessary repulsion force generated by the oppositely flowing currents may be achieved with relatively low driving currents of 10-200 amperes. The thin dielectric film is not molded and is not required to provide mechanical support to a channel wall. Hence, the manufacturing of the resulting solder jet printhead is simplified and its reliability is improved.
    Type: Grant
    Filed: June 7, 1996
    Date of Patent: July 14, 1998
    Assignee: Hewlett-Packard Company
    Inventors: Alfred I. Tsung Pan, Ross R. Allen, Eric G. Hanson
  • Patent number: 5774505
    Abstract: A signal processing channel and method for reducing intersymbol interference in a sequence of data symbols includes a pre-shaping filter for sharpening leading edges of data symbols and providing trailing edges that approximate a decaying exponential. The output of the pre-shaping filter is combined with a cancellation output from a resistance-capacitance circuit having a time constant selected to provide pulse responses that complement the exponentially decaying trailing edges. The combination of the shaped output and the cancellation output is input to a slicer or other decision device. The 2-level output from the slicer is an input to a decision feedback filter that generates the cancellation output. In addition to the resistance-capacitance circuit, the decision feedback filter includes a delay to properly time the coincidence of the cancellation output with the shaped output from the pre-shaping filter.
    Type: Grant
    Filed: April 4, 1996
    Date of Patent: June 30, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Richard A. Baugh
  • Patent number: 5751863
    Abstract: In a design of an optical arrangement for a digital imaging system, optical elements are selected and arranged based upon achieving low levels of aberrations other than distortion, with a distortion level of 5% or greater being introduced by sacrificing distortion-free imaging to achieve such low levels. The distortion of the optical arrangement is characterized and then identified to a digital image processing system, allowing the distortion that is introduced at the optical level to be corrected at the processing level. The approach is to provide front end image shaping that sacrifices distortion-free imaging to control other aberration contributions and then to provide back end digital reshaping to substantially correct the distortion. The identification of front end and back end shaping and reshaping is made with reference to a digitizing sensor that provides the image raw data. In one embodiment, the sensor is a two-dimensional array of sensor elements.
    Type: Grant
    Filed: June 18, 1996
    Date of Patent: May 12, 1998
    Assignee: Hewlett Packard Company
    Inventor: Mina Farr
  • Patent number: 5750300
    Abstract: Embodiments of photoconductors and methods of making photoconductors for electophotography are described, each embodiment comprising a complex between metal oxide phthalocyanine compound(s) and hydroxy compound(s). A metal oxide phthalocyanine pigment exhibits extended photoresponse between 850 nm and 1000 nm when it is milled with a specific hydroxy binder, which preferably includes a modified poly-vinyl butyral binder containing a --CH.sub.2 CH.sub.2 OH unit, a cyclohexanol unit, or another hydroxy unit. Optionally, hydroxy solvents or other hydroxy additives may also be included. Preferably, the pigment is dehydrated or hydroxy-starved before milling with the binder and solvents. The metal oxide phthalocyanine pigments and the hydroxy groups form a complex which extends the photo-response of an OPC to wavelengths beyond about 850 nm, in order to achieve higher xerographic speed with higher resolution.
    Type: Grant
    Filed: April 18, 1996
    Date of Patent: May 12, 1998
    Assignee: Hewlett-Packard Company
    Inventor: Khe C. Nguyen
  • Patent number: 5745128
    Abstract: An ink transfer printing device in which ink transfer is driven by a viscosity change in ink. The ink transfer printing device includes an ink reservoir for retaining ink held under pressure. The ink reservoir is associated with an ink transfer surface which has a plurality of perforations. Under ambient conditions, the viscosity of the ink prevents flow of the ink through the perforations. The ink transfer printing device also includes a viscosity control unit for inducing a change in the viscosity of the ink near certain perforations thereby enabling a controlled amount of the ink near each of these certain perforations to flow through these certain perforations to an outer surface of the ink transfer surface. The ink which has flowed onto the outer surface can then be transferred to an intermediate surface or a printing media. A method for viscosity-driven ink transfer printing is also disclosed.
    Type: Grant
    Filed: August 16, 1996
    Date of Patent: April 28, 1998
    Assignee: Hewlett Packard Company
    Inventors: Si-Ty Lam, Young-Soo You