Abstract: An impact limit stop or crash stop control in a disc drive for setting and maintaining the limits of movement and the stopping distance of a linear or rotary actuator member which supports and moves the transducer heads for bidirectional movement between radial limits with respect to the memory discs. In one of its aspects, this crash stop control provides a low sensitivity, high precision, limit stop adjustment which sets the limits of movement of the actuator member, and which, in another of its aspects, provides a non-linear deceleration characteristic, with some frictional damping, for the actuator member in its limits of movement.

Abstract: An actuator arm assembly for a rotary disc memory drive which comprises a pivotally mounted actuator member and an arm stack unit mounting individual transducer head flexure assemblies. The armstack unit is connected to the actuator member at two locations and requires clamping only at one of the two locations to secure the connection at both locations. The armstack and transducer head flexure assemblies are removable as a unit by unclamping the armstack at that one location, effecting release at both locations, permitting armstack removal as an aligned assembly unit including the transducer head flexure assemblies, circuits and electrical connectors.

Abstract: In a plotter (10) having a plurality of pens (14) stored in a rotatable turret (16) for selective use in a plotting operation, the turret may be rotated by the drive motor (32) used to move the paper (12) bidirectionally, thereby eliminating the cost and weight associated with a pen turret drive motor. The rotation of the turret is mechanically coupled to a grit wheel shaft (34), which is used to move the paper and which is driven by the paper drive motor. The turret is positioned on a spindle (86) provided with slots (88) associated with the location of the pens. The bottom of the spindle is provided with a worm gear (110), which is continuously engaged by a worm (94) mounted on one end of a worm shaft (96). The grit wheel shaft is also provided with a gear (104) which is selectively engageable by a sliding gear (102) mounted on the other end of the worm shaft. A lever engager (98) is actuated by a foot (106 ) on the bottom of the carriage assembly (56) which supports a pen during the plotting operation.

Abstract: This application discloses a thermal ink jet printhead and method of manufacture featuring an improved all-metal orifice plate and barrier layer assembly. This assembly includes constricted ink flow ports to reduce cavitation damage and smooth contoured convergent ink ejection orifices to prevent "gulping" of air during an ink ejection process. Both of these features extend the maximum operating frequency, fmax, of the printhead. The nickel barrier layer and the underlying thin film resistor substrate are gold plated and then soldered together to form a good strong solder bond at the substrate - barrier layer interface.

Abstract: A modular rotary disc drive or disc file having three major subassemblies. These are a rotary actuator structure subassembly having an actuator housing and a pivotally mounted actuator member in said housing, an armstack subassembly including the transducer heads and their electric circuits including the plug terminal therefor, and a magnetic driver subassembly having a magnetic housing and a movable coil assembly. The armstack subassembly is attached and removed from the actuator member without removing the actuator member from the actuator housing. The magnetic housing of the magnetic driver subassembly is secured to the actuator housing and its moving coil assembly is secured to the actuator member. This magnetic driver subassembly is also attached and removed as a unit without removing the actuator member from the actuator housing.

Abstract: An ink delivery system (10) comprising an ink bag or reservoir (14), a bladder (16) and a print head (24) is provided. A valve (38) provides selected fluid communication to permit total closure (no ink flow), fluid communication from the ink bag to the bladder (refill mode) and fluid communication from the bladder to the print head (print mode). The ink bag comprises a material impervious to air and water and bladder comprises a resilient material capable of several refills. Both are mounted on one side of a platform support (12). The valve is mounted in a plenum chamber (22) on the oppsite side of the platform support and is provided with a rotatable valve stem (50) to permit rotation of the valve to its various modes. The print head is mounted on the plenum chamber.

Abstract: A printhead for a thermal ink jet printer or the like is brought into good electrical contact with raised electrical contacts on a flexible interconnect circuit by the use of a molded near-linear spring connect structure. This novel structure includes a horizontal central locating member from which a plurality of resilient hollow cylinders extend vertically upward and in alignment with the electrical contacts on the flexible interconnect circuit. Since there is a near-linear deflection of the cylinder walls with increasing force applied thereto, good electrical contact is achieved between the printhead and the flex circuit using a minimum of force, thereby minimizing the likelihood of damage to the printhead.

Abstract: An improved system and process is provided in a disc drive for determining and for compensating head/track offsets when a data (target) head is moved to a new data (target) track position. Such disc drives typically include an armstack with transducer heads thereon, either pivotally or linearly mounted to move the transducer heads radially across a plurality of memory discs in a disc stack. A dedicated reference head is provided for scanning dedicated servo tracks on a dedicated memory disc, and a data head is provided on each data disc.Head/track position offset is determined by generating an initial position offset signal indicative of the position offset between the dedicated head and an adjacent dedicated track while a selected data head, called the present head, is centered on its data track.

Abstract: The specification describes thermal ink jet (TIJ) processes and device structures produced thereby wherein either heater resistors or heater resistor-diode combinations are constructed vertically upward from a common supporting substrate. A lower or first metal level conductor pattern provides one part of an X-Y matrix multiplex connection to the resistor/diode components, and a second, upper metal level conductor pattern forms the second part of the X-Y matrix multiplex connection. In this manner, the multiplex drive circuitry for the TIJ printhead resistors/diodes may be fabricated (integrated) directly on the thin film resistor (TFR) printhead substrate. Additionally, the second level metal conductors which overlie the resistive heater and diode elements also serve as a barrier shield to ink corrosion and cavitation wear.

Abstract: This application discloses a thermal ink jet printhead and method of manufacture featuring an improved all-metal orifice plate and barrier layer assembly. This assembly includes constricted ink flow ports to reduce cavitation damage and smooth contoured convergent ink ejection orifices to prevent "gulping" of air during an ink ejection process. Both of these features extend the maximum operating frequency, fmax, of the printhead. The nickle barrier layer and the underlying thin film resistor substrate are gold plated and then soldered together to form a good strong solder bond at the substrate-barrier layer interface.

Abstract: A method of increasing the water fastness and print quality of an ink employed in ink-jet printers is provided. The method involves providing a reactive species that reacts with a component in the substrate (i.e., paper) to form a polymer that binds the dye in the ink to the polymeric lattice. Alternatively, a separate reactive component may be deposited on the substrate on the same location as the reactive species which causes a polymeric reaction to occur. In this case, the ink may be in one or the other or both reactive components. An ink-jet printer having indexed orifices permits registration of deposited droplets of ink and reactive species to form the desired product.

Abstract: Improvements are realized in magnetic disc drives in minimizing servo gain variations from one head to another and in differing track offset positions by providing servo code patterns and methods of fabricating such patterns in which magnetic heads of differing widths overlap the same amount of servo code and in which servo gain variations in track offset positions are minimized by maintaining servo code overlap by the magnetic heads relatively constant up to substantially one-half track offsets of magnetic head.

Abstract: A process for preparing an aqueous-based ink composition for use in ink-jet printers in disclosed. The process comprises (a) forming a solution of a dye having at least one negatively charged functional group per molecule; (b) acidifying the solution; (c) cycling the solution through a reverse osmosis membrane to form a concentrate and a permeate, the concentrate including a cation of the compound associated with at least one functional group on the dye and the permeate including a cation formerly associated with at least one functional group; (d) adding water as necessary (e) concentrating the dye by reverse osmosis; and (f) admixing the concentrated dye with at least one glycol ether. The pH of the ink composition is maintained below about 7.

Abstract: A chemical filter is provided for preventing pollutants in the atmosphere from contaminating sensitive electronic equipment, such as hard disc drives. The chemical filter comprises a layer of charcoal or charcoal-impregnated foam to remove organic contaminants and at least one layer of a high surface area metal to remove inorganic pollutants, such as SO.sub.2, H.sub.2 S, NO.sub.2 and Cl.sub.2. In one embodiment, the chemical filter comprises a layer of charcoal, a layer of a copper foam, a layer of a nickel foam and a layer of a particle filter.A method is also provided for preventing pollutant molecules in the atmosphere from contaminating electronic equipment. The method comprises interposing the chemical filter of the invention between the electronic equipment and the source of the pollution, introducing polluted air into the chemical filter, reacting pollutant molecules with the high surface area metal, and introducing filtered air to the electronic equipment.

Abstract: A ribbon shield for a dot matrix printer which is comprised of a step contoured recessed cavity such that the ribbon sequentially wipes against an upper edge, a lower edge, towards the paper, the other lower edge and the other upper edge and the ink removed accumulates in the cavity whereby it is restrained from flowing onto the paper.

Abstract: In a thin film resistor substrate for a thermal ink jet printhead, there is provided an elongated ink feed slot for supplying ink to a plurality of heater resistors on the substrate. Ink flows from this slot vertically through the substrate and then laterally along predetermined ink flow paths in an orifice plate and barrier layer members to ink reservoirs above the heater resistors. In this manner ink flow pressure drops to all of the reservoirs are equal and thereby enhance ink pressure control for all of the reservoirs.

Abstract: In a thin film resistor substrate for a thermal ink jet printhead, there is provided an elongated ink feed slot for supplying ink to a plurality of heater resistors on the substrate. Ink flows from this slot vertically through the substrate and then laterally along predetermined ink flow paths in an orifice plate and barrier layer members to ink reservoirs above the heater resistors. In this manner ink flow pressure drops to all of the reservoirs are equal and thereby enhance ink pressure control for all of the reservoirs.

Abstract: A shaft assembly of a rotary actuator arm structure in a rotary disc memory drive in which all machine operations cutting slots or openings for receiving leaf springs which provide axial and radial loads are performed along axes paralleling the axis of the rotary actuator. One leaf spring provides an axial load on the bearings of the shaft assembly. A second leaf spring fitted between one shaft bearing and the bearing housing thereat provides the radial bearing load.

Abstract: Interferometer apparatus for determining the spatial relationship of two or more observed points such as the height of a magnetic transducer head as it moves over the surface of a spinning recording disc. A monochromatic light beam having components of characteristic polarization and frequency is separated with one component being directed upon the two observation points one of which may be on the transducer head and other may be on the spinning disc. The other component is simultaneously directed upon a reference surface. The reflected beams are then combined to produce an optical beat frequency which is subsequently detected electronically and converted to a voltage representative of the phase shift between images of the two points and utilized to provide the display of the distance between the two points.

Abstract: A preloaded check valve disposed in a valve body between an ink reservoir and a printhead has a valve opening pressure or "cracking" pressure at least sufficient to overcome the hydrostatic pressure due to gravity of ink in the reservoir. This prevents depriming or leakage of ink at the orifices of the orifice plate forming part of the ink ejecting mechanism. Ejection of ink during printing creates a pressure differential across the valve sufficient to cause it to open and replenish the ink supply at the ink ejecting mechanism.