Abstract: As a step in the manufacture of an ink jet printer, a cover (16) is adhesively bonded to a piezoelectric layer (10) having parallel grooves (20) which will serve as ink channels in the finished printer. Mating surfaces are prepared, excess adhesive is applied and bond pressure exerted until surface extremities of the two surfaces come into contact, producing a bond layer of 2 .mu.m or less. To ensure that the flow distance of excess adhesive is uniform over the bond plane, grooves (32) are cut at the margin (30) of the piezoelectric layer.

Abstract: This invention relates to improvements in or relating to ceramic piezoelectric ink jet print heads of the kind having an ink channel for connection to an ink ejection nozzle and to a reservoir for the ink, and a piezoelectric wall actuator which forms part of the channel and is displaceable in response to a voltage pulse thereby generating a pulse in liquid ink in the channel due to a change of pressure therein which causes ejection of a liquid droplet from the channel. Such print heads are referred to hereafter as piezoelectric ceramic ink jet print heads.

Abstract: An ink jet ink especially for printing on to plain paper comprises a suspension in (a) non aqueous solvent of (b) a disperse phase comprising: (i)) a water-insoluble dyestuff which is insoluble in said solvent at the ink jet operating temperature and below; (ii) a water insoluble resinous dispersant for the dyestuff which in the amount used is capable of forming a solution in the said solvent at the ink jet operating temperature, (iii) a polymer binder to hold the dyestuff on the surface of the paper.

Abstract: A method of multi-tone printing employs a drop-on-demand printing apparatus 100 for depositing ink droplets from an array of channels 104 on printing element areas of a substrate 111 which is movable relatively to said apparatus. The channels length and nozzle location and dimensions afford each channel with a high longitudinal resonant frequency and electrically actuable means 110,112,114,116,118 supply energy pulses to a selected band of channels at or near the resonant frequency of the channels to deposit from each selected channel in the corresponding printing element area of the substrate a number of drops equal to the number of pulses applied thereto, the number of pulses applied being dependent on the tone of printing required. Droplet ejection from even numbered channels is in anti-phase at the resonant frequency with droplet ejection from odd numbered channels.

Abstract: A co-fired laminate (10) for use in printheads for drop-on-demand ink jet printers has two inner layers (12, 14) of piezoelectric material which are thickness poled in opposite senses, two outer layers (11, 15) of inactive material and a fifth layer (13) disposed between the inner layers which is electrically insulating under the printhead operating conditions and conductive under the poling conditions of the inner layers. The fifth layer preferably is an N.T.C. material with its critical temperature between the operating and poling temperatures. After poling of the inner layers further manufacture of the printhead from one side thereof can be effected as described.

Abstract: A multi-channel array droplet deposition apparatus has a base sheet comprising a layer of piezo-electric material poled normal thereto, an array of parallel, open-topped droplet liquid channels provided by upstanding channel separating walls formed in the layer, electrodes on channel facing surfaces of the walls, a channel closure sheet bonded to the walls, nozzles respectively communicating with the channels and a droplet liquid supply connecting with the channels, the closure sheet having an array of parallel conductive tracks thereon paced at intervals corresponding with the channel spacing and located parallel to and opposite the channels and bonds, which preferably are solder bonds, mechanically and electrically connect each track to the electrodes of the channel facing walls of the channels opposite thereto and seal the closure sheet to the channels.

Abstract: A method of operating a pulsed droplet deposition apparatus, e.g. a drop-on-demand ink jet printer, having a droplet liquid chamber (16) with which a nozzle (18) communicates for expulsion of droplets (12) from the chamber, droplet liquid replenishment means (20) connected to the chamber and energy pulse applying means for imparting pulses of energy to the droplet liquid in the chamber, employs, to increase the volume of droplets expelled by respective energy pulses, a droplet liquid having high viscosity at low shear rate and low viscosity at high shear rate, the liquid relaxation time constant being of the same order or greater than the period of pulses applied to the liquid and the characteristic time of the liquid in the nozzle being of the same order or less than the period of the pulses.

Abstract: Multi-channel droplet deposition apparatus of the kind having an array of parallel channels (1-11) with which respective nozzles and common ink supply communicate and in which electrically actuable devices (21-31) are located in relation to said channels to impart energy pulses to selected channels for effecting droplet ejection therefrom is operated by applying energy pulses to selected channels of the array and channels in the vicinity of the selected channels the amplitudes of which depend on the value of the compliance ratio of the channel walls to the droplet liquid and which together produce a pressure distribution in the channels to which they are applied which both effects droplet ejection from only said selected channels and is substantially free from pressure crosstalk between said selected channels or between said selected channels and other channels of the array.

Abstract: This invention relates to a method of testing multi-channel array pulsed droplet deposition apparatus (10) comprising a multiplicity of parallel channels (12) each with pulse imparting means for expelling droplets therefrom. The apparatus is located opposite a test module (20) having detecting elements (21) with channels of the apparatus opposed and close to the respective elements. Coupling fluid (23) fills the channels (12) to be tested and the space between the apparatus and the test module. Test signals are applied to impart energy pulses to the fluid in the channels opposite the detecting elements so that signals are passed to those elements by way of the fluid which are evaluated to assess the channel performance. Various forms of the detector elements and the apparatus are disclosed.

Abstract: A method of multi-tone printing employs a drop-on-demand printing apparatus for depositing ink droplets on printing element areas of a substrate which is movable relatively to the apparatus. The droplets are deposited from an array of channels on the substrate which is movable relatively to the channels. The channels length and nozzle location and dimensions afford each channel with a high longitudinal resonant frequency and energy pulses are supplied to selected channels at or near the resonant frequency of the channels to deposit from each selected channel in the corresponding printing element area of the substrate a number of drops equal to the number of pulses applied thereto, the number of pulses applied being dependent on the tone of printing required. Single channel and color versions of the invention are also disclosed.

Abstract: A recording transparency and method of preparing the same from water solution are disclosed. The transparency is receptive to a wide variety of inks and other indicia, exhibits rapid ink drying times, excellent dot size and shape retention, and excellent water resistance and stability. The transparency comprises a transparent substrate coated from an aqueous solution of a polymeric sorbent selected from synthetic transparent cellulosic polymers, especially one or a mixture of hydroxyethyl cellulose polymers, and a surfactant composition comprising nonionic detergent, anionic detergent and complexing agent.

Abstract: An ink jet composition and method of printing on plain paper are provided wherein the composition comprises a colloidal solution of a nonaqueous solvent (e.g. selected glycol ethers) and a disperse phase comprising a resin (e.g. a selected ethylene-vinyl acetate copolymer) which is soluble in the solvent at room temperature and a dyestuff which is soluble in the resin at room temperature but substantially insoluble in the solvent at room temperature. The ink composition is fluid and may have a very low viscosity at room temperature.

Abstract: A method of manufacturing one or more nozzles for an ink jet printhead initially comprises bonding a nozzle plate to the ink ejection end of the printhead. A mask is then secured in contact with the nozzle plate, the mask having a plurality of apertures each defining a respective nozzle exit. Laser radiation applied to the mask exposes the areas defined by the apertures to ablate the plate material between the nozzle exits on the external surface of the plate and corresponding nozzle inlets on the opposite surface of the plate. The assembly comprising the printhead, plate and mask is rocked during the exposure step to increase the area of the nozzle inlet relative to its outlet. Also, prior to the nozzle formation step, one or more ink troughs may be provided for supplying an external source of ink for each nozzle. The ink troughs, which may be formed using laser ablation techniques similar to those used in the formation of the nozzles, facilitate a continuous, positive flow of ink through the nozzles.

Abstract: The method of forming a pattern on a substrate is described which includes first applying a film of thermo plastic material under pressure to a substrate. Energy is then supplied to dissipate heat at the surface of the film facing the substrate thereby to bond the film to the substrate. Next, areas of the film are selectively dry etched to form a predetermined pattern on the substrate and this is followed by depositing on the substrate in the areas where the film has been dry etched, a layer of patterning material. Finally, dry removal from the substrate is effected of the film remaining thereon. There is also described the application of this method to the manufacture of an array, drop-on-demand ink jet printer.

Abstract: A method of operating a pulsed droplet deposition apparatus for ejecting a liquid droplet from a nozzle supplied by a liquid retaining chamber comprises applying a first energy pulse to the liquid in the chamber of sufficient energy to effect expulsion of a droplet from the nozzle and thereafter applying a further energy pulse to the liquid in the chamber to insure that the meniscus of the body of liquid to which the droplet is attached is convex in the direction of motion of the droplet at the time of detachment of the droplet, so as to propel the droplet along the axis of the nozzle. The second pulse has an energy content which is insufficient to alone effect droplet ejection.

Abstract: A method of providing the surface area of a substrate with a first zone which is solvent-wettable and a second zone which is solvent-non-wettable, and which is particularly suitable for application to the printheads and nozzle plates of drop-on-demand ink jet printers or like products where the spacing between zones of the same kind can be as little as just tens of microns, and wherein the solvent-non-wettable zone displays excellent abrasion resistance and resistance to solvents, is virtually non-wettable by a wide range of solvents and bonds well even to plastics substrates, comprises:(i) providing a surface having good solvent wettability at least over that part of the area of the substrate which is to form said first zone;(ii) providing said area with a first layer which comprises siloxic material which bonds to the substrate and which is in contact with the substrate over at least that part of the area which is to form said second zone;(iii) providing said area with an overlayer comprising organic fluoro

Abstract: An ink jet ink composition and method of printing on plain paper are provided wherein the composition comprises a mixture of a nonaqueous solvent (e.g. selected glycol ethers), a resin (e.g. an ethylene-vinyl acetate copolymer) which is substantially completely soluble in the solvent at elevated operation temperatures but substantially insoluble in the solvent at room temperature and a dyestuff which is soluble in the resin at room temperature and above but substantially insoluble in the solvent at room temperature. The ink composition is fluid at room temperature, and has very low viscosity at elevated operating temperatures.

Abstract: Jet printing ink compositions characterized as having low volatility, low viscosity and low variation of viscosity with respect to temperature are disclosed. The compositions comprise a coloring agent dissolved or dispersed in a liquid vehicle which is preferably substantially free of added water and is a propylene glycol ether or an ethylene glycol butyl ether in which the coloring agent is soluble or dispersible.

Abstract: An integral abrasive cutting tool comprising a multiplicity of equally spaced parallel coaxial abrasive cutting discs is formed by rotating a cylindrical mandrel coated with a matrix of abrasive powder in a metal in a fluid bath. A wire is aligned tangentially with the coating and voltage pulses are applied therebetween while the wire is fed in its lengthwise direction past the coating. The wire is translated axially to each of a plurality of disc spacing locations and, at each such location, translated radially to effect electro erosion of the coating forming a channel therein. An abrasive cutting disc is thereby provided between each pair of successive channels.

Abstract: A pulsed droplet ink jet printer has relatively long thin ink channels extending in parallel between an ink manifold 13, and a nozzle plate 5 providing a nozzle 6 for each channel. Side walls 11 may be formed substantially entirely of piezo-electric material so as to be displaceable transversely into a selected channel on the application of an electric field. This transverse displacement produces an acoustic wave in the channel which results in the ejection of an ink droplet. The side walls may deflect in shear mode to a cross-section of chevron formation. Usefully, it is arranged that both side walls adjoining the selected channel are displaced inwardly of the channel to cooperate in droplet ejection. Under this arrangement, the channels are assigned alternately to first and second groups of channels, only one group of channels being capable of actuation at any one instant.