Abstract: A method of bonding ink jet printhead components together by coating a flexible substrate with a relatively thin, uniform layer of an adhesive having an intermediate non-tacky curing stage with a shelf life with around one month for ease of alignment of the parts and ease of storage of the components having the adhesive thereon. Transferring about half of the adhesive layer on the flexible substrate to the high points or lands of one of the printhead components within a predetermined time of the coating of the flexible substrate by placing it in contact therewith and applying a predetermined temperature and pressure to the flexible substrate prior to peeling it from the printhead component. This causes the adhesive to fail cohesively in the liquid state, assuring that about half of the thickness of the adhesive layer stays with the flexible substrate and is discarded therewith, leaving a very thin uniform layer of adhesive on the printhead component lands.

Abstract: An aperture plate for an ink jet printer of the continuous stream type is made corrosion resistant to the ink for long printer operating times. The aperture plate is made corrosion resistant by ion implantation, preferably of chromium ions by an ion beam implanting device. The walls of the aperture plate nozzles are substantially uniformly implanted by rotating and concurrently angling the aperture plate relative to the ion beam direction. The ion beam density and ion potential are regulated to predetermined ranges to assure effective corrosion protection while preventing overheating which will warp or embrittle the aperture plate.

Abstract: An electrohydrodynamic stimulated ink jet printing device and method of manufacture which eliminates the prior art problem of ink wetting the dielectric spacer between the stimulating electrode and the ink jet nozzles. The nozzles are electroformed on one side of a sheet of dielectric material and the EHD electrodes are electroformed on the other side of the dielectric material in registration with the nozzles. The dielectric material is removed from the nozzles by using the nozzles or the electrodes as masks. The internal surface of the dielectric material is coated with a one of a number of coatings non-wettable by the ink such as a mixture of paraffin and ethylene vinyl acetate copolymer dissolved in a light aliphatic hydrocarbon, such as VMP naphtha.

Abstract: A method for controlled fabrication of a waveguide region in a crystalline member, such as lithium niobate. The crystalline member is placed within a crucible which gives off the same metal component as the crystalline member at a predetermined temperature. Both the crystalline member and the crucible are heated in a controlled highly oxidizing atmosphere. During fabrication of the waveguide region, this atmosphere enhances oxidation of optical damage inducing impurities in the crystalline member. Waveguides so fabricated resist the development of laser induced optical damage.

Abstract: An ink jet printhead having an internal, integrated filtering system and fabricating process therefor is disclosed. Each printhead is composed of two parts aligned and bonded together. One part is a substantially flat substrate which contains on a surface thereof a linear array of heating elements and addressing electrodes. The other part is a flat substrate having a set of concurrently etched recesses in one surface. The set of recesses include a parallel array of elongated recesses for use as capillary filled, ink channels having ink droplet emitting nozzles at one end and having interconnection with a common ink supplying manifold recess at the other ends. The manifold recess contains an internal, closed wall defining a chamber with an ink fill hole. Small passageways are formed in the internal chamber walls to permit passage of ink therefrom into the manifold.

Abstract: A continuous stream type ink jet printhead utilizing constant thermal pulses to perturbate the ink streams emitted through a plurality of nozzles to break up the ink streams into droplets at a fixed distance from the nozzles whereat the drops are individually charged by a charging electrode in accordance with digitized data signals. Each printhead has a manifold, a plurality of ink channels communicating at one end with the manifold and terminating at the other end with nozzles, and at least one resistor addressed by a predetermined frequency of current pulses for applying thermal pulses to the ink. In one embodiment, a resistor is positioned in each of the channels adjacent the nozzles and in another embodiment, a single resistor is located in the ink manifold. The resistors are pulsed at low power to generate a perturbation of ink properties such as density, viscosity, or surface tension without producing a phase change in the ink.

Abstract: An improved thermal ink jet printhead is disclosed for ejecting and propelling ink droplets on demand along a flight path toward a recording medium spaced therefrom in response to receipt of electrical input signals representing digitized data signals. Each printhead has one or more capillary filled ink channels. The channels have a droplet emitting nozzle on one end and connect to an ink supplying manifold on the other end. Each channel has a heating element upstream from the nozzle that is located in a recess. The heating elements are selectively addressable with a current pulse for substantially instantaneous vaporization of the ink contacting the addressed heating element to produce a bubble that expels a droplet of ink during its growth and collapse.

Abstract: A thermo-optic light modulation array is disclosed for use in an imaging system of an electrophotographic printer to produce electrostatic latent images. The array comprises a light transmitting medium arranged in contact with an array of pixel shaped heaters which are selectively energized in response to digitized data signals for pulse heating the portions of the medium in vicinity of the heaters. Temperature gradients in the medium produced by the energized heaters cause changes in the index of refraction of the medium, so that selected portions of a sheet of collimated light directed through the temperature gradients in the light transmitting medium are deflected or modulated. The modulated light may be blocked by a stop and the unmodulated light may be directed to the precharged photoconductive member of the printer to form the latent images or visa versa. Several modes of light modulation are disclosed.

Abstract: A multicolor ink jet printhead for use in a continuous stream ink jet printing system is disclosed. Each ink emitting nozzle is supplied from a separate ink reservoir under a predetermined pressure to an associated inlet in a common droplet generator. A means of passage is provided from the inlet of the droplet generator to a respective nozzle through a medium in the droplet generator resonance cavity. The passage means maintaining the separation of the various colored inks from the cavity medium, the passage means being relatively impedance matched when the cavity medium is liquid or a solid. Therefore, a single acoustic driver and droplet generator may be used for perturbating the different colored inks emitted from the nozzles thereof. In one embodiment, each of the multicolored streams of ink droplets emitted from the nozzles are fanned in a direction perpendicular to the translation direction of the printhead, so that a swath of information is printed on a stationary but steppable recording medium.

Abstract: An ink jet printhead composed of substantially two identical parts and method of batch fabricating the parts. Each part has V-grooves anisotropically etched between a linear array of heating elements having selectively addressable electrodes which are parallel to each other. The grooved structures of the parts permit them to be mated face-to-face, so that they are automatically self-aligned by the inter-meshing of the lands containing the heating elements on one part with the grooves of the other part. A pair of parts may be used as a printhead for a carriage type ink jet printer or a plurality of parts may be assembled for a pagewidth printer. The pagewidth printhead is assembled by offsetting the first two parts a selected number of grooves when they are mated so that the subsequently added adjacent parts abut each other and yet are self-aligned with the confronting parts.

Abstract: Several fabricating processes for ink jet printheads are disclosed, each printhead being composed of two parts aligned and bonded together. One part is a substantially flat substrate which contains on the surface thereof a lineal array of heating elements and addressing electrodes, and the second part is a substrate having at least one recess anisotropically etched therein to serve as an ink supply manifold when the two parts are bonded together. A lineal array of parallel grooves are formed in the second part, so that one end of the grooves communicate with the manifold recess an the other ends are open for use as an ink droplet expelling nozzles. Many printheads can be made simultaneously by producing a plurality of sets of heating elements array with their addressing electrodes on a silicon wafer and by placing alignment marks thereon at predetermined locations.

Abstract: A liquid crystal image bar for an electrophotographic printer is disclosed, having a nematic liquid crystal device with crossed polarizers configured as a single array of dot shutters that are driven by a single frequency voltage source. The image bar produces latent electrostatic image on the printer's photoconductive member one line at a time in response to receipt of digitized data signals. During the operational mode, all of the image bar shutters are energized and, in this electrically driven state, the image bar shutters are non-transmissive. The latent image is produced by selective erasure of precharged background areas on the member. For the erasure to occur, interruption of the driving voltage to selected shutters in response to the data signals cause the selected shutter to become transmissive because the liquid crystal material enters a transient state. The response time for the transmissiveness is about one millisecond.

Abstract: An ink jet printhead for use in a thermal ink jet printer having bubble-generating heating elements formed symmetrically around the entrances to passageways in the ink-holding printhead chamber that terminate as nozzles. The heating elements are individually addressable with current pulses to form vapor bubbles, which, during collapse, produce an impact force that expels and propels droplets toward a recording medium. An alternate embodiment includes an ultrasonic generator in the printhead chamber to produce pressure waves in the ink contained in the chamber. The current pulse applied to the heating element is synchronized with the lower pressure wave to obtain bubble growth with substantially lower temperatures resulting in a more energy efficient printhead.

Abstract: A thermal ink jet printhead ejects ink droplets on demand by utilizing the conservation of momentum of collapsing bubbles in a layer of liquid ink having a predetermined thickness. The printhead has an ink containing chamber with an array of individually addressable heating elements on one chamber interior surface which are aligned with an elongated opening in a parallel, confronting chamber wall. The spacing between the chamber wall with the elongated opening and the chamber surface with the heating elements provide the desired ink layer thickness. Selectively addressed heating elements momentarily produce vapor bubbles in the ink layer. When the bubbles collapse radially inward towards their respective heating elements, an oppositely directed force perpendicular to the heating element is generated which is large enough to overcome the surface tension of the ink in the elongated opening and propel a droplet of ink therefrom towards a recording medium.

Abstract: A ink jet printer having a reciprocating printhead with a single jet to print full pages of information on a recording medium by printing contiguous swaths of information. The recording medium is stepped a distance of one swath height after each swath is printed. A height control sensor is located on one side of the recording medium to receive periodically one or more sweeps of test droplets. The height control sensor has upper and lower pairs of photodetectors to detect droplets passing thereby and to produce differential sensing signals which identify the droplet having a trajectory closest to the desired trajectory. By determining the number of droplets between the identified droplets, the interdroplet spacing and drift of the droplet trajectories is monitored. In response to the height control sensor signals, the printer controller with associated circuitry adjusts the operating parameters of the printer to correct and to maintain the desired droplet trajectories and interdroplet spacings.

Abstract: A plurality of disposable, individually replaceable ink supply cartridges are mountable on the carriage of an ink jet printer. Each cartridge has a thermal printhead fixedly attached thereto. A constant slightly negative pressure is maintained at the nozzles of the printhead by means of a secondary reservoir with a level of ink maintained below the ink supply. The majority of the ink is stored in a hermetically sealed main reservoir in the cartridge which contains the ink supply at the negative pressure. A passageway provides ink from the main reservoir to the printhead nozzles. The secondary reservoir holds an air pocket at atmospheric pressure and releases air into the main reservoir as required to maintain the desired negative pressure constant therein as the ink supply is depleted. The passageway entrance is sized to maintain a meniscus when the cartridge is tilted to prevent loss of the desired nozzle pressure by air from the second reservoir.

Abstract: A cleaning apparatus for a recording head in a magnetographic printing device of the type having a movable magnetic imaging tape in endless belt form is disclosed. The apparatus is especially effective for cleaning thermal printheads for thermoremanent magnetic imaging systems, and comprises a cleaning member adapted for reciprocal movement into and out of a nip formed by the magnetic tape and the printhead. In one embodiment, the cleaning member is a flexible substrate attached at one end to a rotatably mounted spool. The substrate is wound on the spool with the loose end resting on a guide plate and confronting the nip. The spool is periodically rotated to drive the substrate through the nip while the tape is moving and then is rotated in the opposite direction to rewind the substrate and withdraw it from the nip. In another embodiment, the cleaning member is a flexible substrate which is maintained in a planar configuration by parallel guide plates.

Abstract: An energy efficient means for selectively pre-magnetizing a magnetic recording medium of a thermoremanent magnetographic printer is disclosed. It consists of a pair of axially aligned, elongated two-pole, substantially cylindrical permanent magnets separated by a narrow gap and oriented so that like poles of adjacent magnets confront one another across the gap. The recording medium moves between the magnets in a direction perpendicular to the magnets. The elongated magnets produce magnetic field components that are additive in the surface of the recording medium and that cancel in the direction normal to the recording medium's surface. The magnetizing field of the magnets may be turned off for latent image retention by rotating the magnets about 90 degrees.

Abstract: An improved continuous stream ink jet printer is disclosed that conducts pagewidth printing via an array of fixed nozzles which direct droplets towards a moving recording medium. Each nozzle is assigned a segment of a printable line that extends across the entire width of the recording medium. The droplets from each nozzle are charged with printing information and fanned along its segment to specific pixels locations or to a gutter for recirculation. Distance sensing sensors are located below the droplet trajectories, parallel to the recording medium surface and perpendicular to the direction of movement of the recording medium. The distance sensing sensors periodically produce signals representative of the actual throw distance of the droplets and compare the signals indicative of the actual throw distance to a signal representative of the distance from the nozzles to a predetermined printing plane.

Abstract: A carriage type, bubble jet ink printing system having improved bubble generating resistors that operate more efficiently and consume lower power, without sacrificing operating lifetimes. The resistor material is heavily doped polycrystalline silicon which can be formed on the same process lines with those for integrated circuits to reduce equipment costs and achieve higher yields. Glass mesas thermally isolate the active portion of the resistor from the silicon supporting substrate and from the electrode connecting points, so that the electrode connection points are maintained relatively cool during operation. A thermally grown dielectric layer permits a thinner electrical isolation layer between the resistor and its protective, ink interfacing tantalum layer, thus increasing the thermal energy transfer to the ink.