Abstract: Four microprocessors type Intel 8051 collectively map one print buffer containing 136 ASCII character codes, each of a nominal 64 different types, into the control of 136 print hammers at an associated 136 columnar print positions. The print hammers are controlled to fire upon a selected one scan time interval of 690 microseconds, one of a total of 67 such scan time intervals within a 46.7 millisecond print time period. Print hammers are controlled to fire at a particular scan time interval in order to print a character from a then oppositely juxtaposed character font upon a circulating print band.

Abstract: A novel impulse ink jet ink for use with an ink jet system having material subject to corrosion by said ink is disclosed. The subject ink comprises a fatty acid vehicle, a colorant, and amounts of anti-oxidant, preferably an alkylated hydroquinone, which are effective to substantially reduce the rate of corrosion on metallic parts of the system. The preferred anti-oxidant, which comprises 0.1-5 wt % of the ink, is an alkylated hydroquinone, particularly butylated hydroquinone. The subject ink preferably comprises an oleic acid vehicle, and a vehicle additive selected from the group consisting of aromatic alcohols, aromatic ethers, dimethylsulfoxides, alkyl pyrrolidones, methoxy- and ethoxy- triglycols, aliphatic ketones, and mixtures thereof. The corrosive nature of such inks is potentiated by the relatively high percentages of the vehicle-soluble dyes in the ink. Such dyes are present in amounts up to 20 wt % of the ink.

Abstract: Ink jet apparatus for use with hot melt ink has an integrally connected ink jet head and reservoir system, the reservoir system including a highly efficient heat conducting plate, such as aluminum, inserted within an essentially non-heat conducting reservoir housing. The reservoir system has a sloping flow path between an inlet position and a sump from which ink is drawn to the head, and includes a plurality of vanes situated upon the plate for rapid heat transfer.

Abstract: An impulse ink jet apparatus includes a plurality of lengthwise expandable piezoelectric transducers, each of the transducers varying the volume of a compression chamber in order to eject droplets of ink therefrom. Mechanical cross talk propagating along a support structure for the transducers is minimized by effectively decoupling each transducer from its neighbors. In one approach, the support structure rigidly supports each transducer at displacement nodal points thereof, while in another approach the lengths of the transducers are uniquely varied with respect to their neighbors.

Abstract: A method and apparatus for supplying ink to an array of ink jets is provided by two fluidically independent reservoirs, each reservoir supplying ink to a respective end of a manifold which communicates with the array of ink jets via their inlet restrictors. During normal operations involving an acceleration of the array along a scanning path, the ink levels in the two reservoirs will remain the same since any difference in their levels will create a pressure differential that drives a flow of ink through the manifold from the higher level reservoir until such time that their levels equalize.

Abstract: An impulse ink jet apparatus includes a plurality of lengthwise expandable piezoelectric transducers, each of the transducers varying the volume of a small compression chamber which is supplied ink from a reservoir by an ink flow path defined by a stack of thin plates held together upon the rigid forward face of a print head by a spring plate and U-clip.

Abstract: An elongated unitary spring armature is disclosed for use in dot matrix printers. The spring armature has an elongated triangular shape with attachment means located adjacent to the base and means for securing the impact tip located adjacent to the apex. A spring portion formed of a high carbon steel is located adjacent to the attachment means and an armature portion formed of a low carbon steel separates the spring portion from the apex. Processes for making the spring armature are also disclosed.

Abstract: A transducer array for an ink jet printing apparatus includes a plurality of discrete transducer elements, each of which are comprised of a poled ferroelectric material arranged and bonded along one face thereof to a rigid substrate by a thermoplastic cement. The opposite face of each of said transducer elements is bonded at one end to a coupling means communicating within an ink jet chamber having an ink droplet ejection orifice, and at the other end to rigid support means, a means for bonding both ends comprised of a structural-type conductive epoxy having a predetermined cure temperature. A method for fabricating such an array includes the steps of heating the bonded transducer elements at the cure temperature, but below a second predetermined temperature representative of the temperature at which the thermoplastic cement readily flows.

Abstract: A stearic acid-containing ink jet ink for use in an ink jet apparatus which features good print quality. The ink jet ink is discharged from the ink jet ink apparatus at elevated temperatures above ambient.

Abstract: A multi-layer transducer array for an ink jet apparatus having a plurality of variable-volume chambers includes a plurality of thin plates of piezoceramic material stacked one upon the other. Each of the plates are adapted to be coupled to a respective one of the chambers, and are formed with an active piezoelectric region which is separated from a structured region by a cut through the material leaving only one end of the active region connected to the structural region. One side of the active region is coated with a conductive material, thereby providing electrical connection to a thin foil strip arranged at the end of the plate remote from the chambers. Successive layers of such plates are stacked one on top of the other, with adjacent active regions staggered relative to each other, and with the thin foil strip between adjacent pairs of plates providing both mechanical isolation and a connection for electrical signals to pulse selected transducers.

Abstract: A method of fabricating an ink jet apparatus of the type having a plurality of variable volume chambers arranged in an array, each of the chambers adaptive to receive ink from a reservoir and including an orifice for ejecting droplets of ink-on-demand, is facilitated by utilizing a ganged array of transducer feet which are inserted into the chambers, joined to the respective transducer and unganged by lapping off an interconnecting web flushed with the forward face of the image head.

Abstract: An atmospheric probe for detecting the occurrence and measuring the extent of ice accretion upon the probe.

Abstract: A method of ejecting droplets of phase change or hot melt ink jet ink upon a target such as paper includes a step of applying pressure to the droplets after they have cooled upon the paper in order to increase their coverage and, thus, minimize the volume of ink required to produce a high quality print with a high degree of resolution. Including a means for applying pressure to the cooled droplets, a suitable apparatus increases the area of the target covered by a particular droplet after spreading by at least five percent and preferably by twenty percent.

Abstract: Hot melt ink is maintained in a solid state. When ink is called for in the reservoir of a scanning imaging head, the head is moved to a position coupled to the solid state ink whereupon the ink is melted coupled into the reservoir of the imaging head.

Abstract: A cartridge for hot melt or phase change ink is tubular, having a cover at one end and an opening at the other end. Upon engagement and cooperation between the cartridge and a reservoir, solid ink is dropped under the influence of gravity through the opening in the cartridge. Solid ink is retained in the cartridge until such cooperation, which includes keying the cartridge to the reservoir and forming a seal of the inlet to the reservoir between the cartridge and the reservoir.

Abstract: A system for printing dot-matrix characters wherein a double column of dot forming elements is used, and no single dot forming element is required to print more often than once in any four column interval of printed text. Means for timing the actuation of the dot forming elements wherein the "on" time of the individual actuators can be longer than the time interval between columns is included.

Abstract: A cooling apparatus for a hammer bank assembly of an impact printer. The cooling apparatus directs air onto each hammer and magnet of the hammer bank assembly and maintains the temperature differential of the hammers and magnets within predetermined ranges.

Abstract: An improved dot matrix actuator is provided which includes a magnetic circuit formed of a yoke assembly and a pivotal armature. The armature is pivotally supported with respect to the yoke by means of a flexure assembly which eliminates the need for a true pivot between the two elements. The elements are shaped so as to maintain a constant small air gap therebetween so as to maximize the magnetic efficiency of the device while eliminating wear. The device is operated just below saturation of the magnetic circuit in order to maximize efficiency. In addition, the actuator includes several features for maximizing its speed and operational efficiency.

Abstract: A paper clamp is provided for a computer printer in which the paper is continuously clamped while the paper is advanced and printed. In one embodiment, a clamp magnet is positioned on one side of the paper path opposite a clamp plate on the other side of the paper path. The paper is clamped by the magnetic attraction between the clamp magnet and clamp plate.

Abstract: An improved dot matrix actuator is provided which includes a magnetic circuit formed of a yoke assembly and a pivotal armature. The armature is pivotally supported with respect to the yoke by means of a flexure assembly which eliminates the need for a true pivot between the two elements. The elements are shaped so as to maintain a constant small air gap therebetween so as to maximize the magnetic efficiency of the device while eliminating wear. The device is operated just below saturation of the magnetic circuit in order to maximize efficiency. In addition, the actuator includes several features for maximizing its speed and operational efficiency.