Abstract: The invention describes a method of forming a drop-on-demand printing apparatus having a body formed with a high density array of parallel channels (13) extending normal to the array direction, nozzles (27) connected respectively with the channels, printing liquid supply means with which said channels each communicate and pressure pulse applying means provided with each channel to apply pressure pulses to the channel liquid to effect droplet ejection, in which the body is formed by a plurality of like modules (2) serially butted together at facing end surfaces (49, 51) which are normal to the array direction, the arrangement enabling ejection of droplets from the channels so that said droplets are deposited on a printing surface at a predetermined spacing transversely to the direction of relative movement between the apparatus and said surface.

Abstract: Ink jet printhead components are formed initially by bonding together a grooved base wafer and a suitable cover wafer, the area of the bonding wafer assembly being sufficient to provide a 14.times.14 array of components. Using a datum formation, the wafer assembly is divided into strips and linear processing steps are conducted, such as applying nozzle plates and laser ablating nozzles. Each strip can then be divided to form separate printhead components.

Abstract: A fiber preform having a web and at least one flange has fibers disposed in the web such that each follows a zig-zag path and is interlocked with the fibers of the flange. A manufacturing method for the preform includes interlocking the web yarns with those of the flange and engaging the web yarns at a plurality of points spaced longitudinally of the prefrom and also spaced from the flange in the direction of the web to define the required web dimension.

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 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 pulsed droplet ink jet printer has at least one channel communicating with a nozzle. The side wall of the channel is formed as a shear mode piezo-electric actuator comprising an unpoled crystalline material. Electrodes applied to the actuator enable an electric field to be applied such that the actuator moves in transversely of the field to change the liquid pressure in the channel and thereby eject a droplet through the nozzle. The actuator can be made in two parts so as to deform, in cross section, to a chevron formation.

Abstract: A high density multi-channel array, electrically pulsed droplet deposition apparatus comprises a bottom sheet of piezoelectric material poled in a direction normal to said sheet and formed with a plurality of parallel channels mutually spaced in an array direction normal to the length of said channels. Each channel is defined by a pair of facing side walls and a bottom surface extending between the respective side walls. A top sheet facing said bottom surfaces of said channels and bonded to said side walls closes the channels at their tops. Each of at least some of the side walls include electrodes on opposite sides thereof to form shear mode actuators for effecting droplet expulsion from the channels associated with the actuators.

Abstract: A pulsed droplet ink jet printer has at least one channel communicating with a nozzle. The side wall of the channel is formed as a shear mode piezo-electric actuator. Electrodes applied to the actuator enable an electric field to be applied such that the actuator moves in the direction of the field to change the liquid pressure in the channel and thereby eject a droplet through the nozzle. The actuator can be made in two parts so as to deform, in cross section, to a chevron formation.

Abstract: A multi-channel array, pulsed droplet ink jet printer comprises a plurality of channels each communicating with a respective nozzle. A side wall of each channel is formed as a shear mode piezo-electric actuator. Electrodes applied to the actuators enable electric fields to be applied such that the actuators move laterally in the direction of the field to change the liquid pressure in the channels for effecting droplet ejection through the channel nozzles. The actuators can be made in two parts so as to deform, in cross section, to a chevron formation.

Abstract: A housekeeping manifold is provided at the end of a row of ejector apertures of a drop-on-demand printhead module. The housekeeping manifold includes upper and lower parts disposed on opposite sides of the row of ejector apertures, a trench extending between the manifold parts through which ink drops from the ejector apertures are discharged, openings between the manifold parts and the trench and a ducting arrangement for supplying environmental fluids to or exhausting such fluids from the region of said apertures by way of the manifold parts and trench.

Abstract: A drop-on-demand ink drop printhead is mounted fixed in a printer for selectively printing drops of ink in a print line. The printhead comprises a plurality of stacks of like print modules arranged in side-by-side relationship to form a number of laterally offset module layers. Each of the modules includes at least one group of uniformly laterally spaced ink ejectors, the groups in each layer being laterally spaced by the same amount such that drops from overlapping portions of two or more of the groups interleave to form a segment of the print line. Make-up ink and air supply ducting arrangements are provided for the modules in each stack.

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.

Abstract: A pulsed droplet ink jet printer has at least one channel communicating with a nozzle. The side wall of the channel is formed as a shear mode piezo-electric actuator. Electrodes applied to the actuator enable an electric field to be applied such that the actuator moves in the direction of the field to change the liquid pressure in the channel and thereby eject a droplet through the nozzle. The actuator can be made in two parts so as to deform, in cross section, to a chevron formation.

Abstract: An ink jet"drop-on-demand" printer has a number of parallel channels each containing ink. A thread of mercury extends longitudinally of each channel or pair of channels and is connected for electrical current flow. A magnetic field is applied orthogonally to the channel plane such that current flow in a selected channel causes electromagnetic deformation of the mercury thread. This leads to a pressure pulse in the ink causing ejection of an ink droplet. With a mercury thread shared between a pair of channels, current in the opposite sense results in droplet ejection from the opposite channel of the pair.

Abstract: A process for impregnating a continuous sheet of glass fibre web, paper, carbon fibre, cloth etc., which comprises feeding the sheet continuously into a closed vessel filled to a suitable height with a polymer solution, immersing the sheet under the surface of polymer solution while causing solvent boiling to occur and solvent vapor bubbles to flow out of the sheet, whereby bubbles of gas, such as air held or absorbed in the sheet during the immersion, are automatically removed from the sheet and then withdrawing the sheet from the vessel.

Abstract: This invention relates to apparatus for cooling a mercury vapor lamp, or other longitudinally-extending body, by causing a flow of cooling air to pass along a conduit extending along the length of the lamp. The source of the coolant is a blower directing air along the interior of an open-sided housing extending in parallel with the direction of movement of the lamp. A scoop at one end of the conduit projects into the interior of the housing so as to direct the flow of cooling air passing along the housing into the interior of the conduit at all relative positions of the lamp and housing. In one preferred form of the invention the housing functions as one of the guide rails on which the lamp is mounted for reciprocal movement.

Abstract: Apparatus for shirring a tubular casing includes a pair of shirring wheels with helical teeth.The wheels 21,22 (FIG. 9) are moulded from flexible rubber or polyurethane. The leading edge 43 of a tooth of one wheel 22 is aligned (shown by a nominal straight line 48) with the leading edge 42 on the adjacent tooth on the other wheel 21.The helical teeth are of controlled flexibility and the wheels may include circumferential walls joining the teeth.Other features of the invention relate to the curvature of the crest or face surface of the teeth which are related to wheel diameter and to the desired diameter of the shirred stick or slug which is to be produced.

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.