Abstract: The selected ink channels of a drop-on-demand ink jet printer are caused to expand and then contract, ejecting ink droplets by the application of unipolar voltages first to selected channels and then to non-selected channels. Further unipolar voltages, delayed in time by 2L/c and scaled by a pressure wave reflection coefficient r of the nozzle, effect prompt cancellation of residual pressure waves so that adjacent channels are ready for actuation with minimum delay.

Abstract: In a multi-drop system, a drive pulse voltage for increasing a volume of an ink chamber is applied for a time of AL, a drive pulse voltage for decreasing the volume of the ink chamber is subsequently applied for a time of 2AL, application of the drive pulse voltage is thereafter paused for a time of AL, and the same timing operation is thereafter repeated again to perform emission of an ink drop a plurality of times, where AL is a time required for a pressure wave in an ink chamber to be transmitted from an end to the other end in the ink emission direction. The drive pulse voltage for emitting a last ink drop forming a part of a one-dot liquid drop is applied for a time of 2AL, application of the drive pulse voltage is thereafter paused for a time of AL, and a dumping pulse voltage is thereafter applied in a direction in which the volume of the ink chamber is decreased.

Abstract: Nozzles for an ink jet printer are formed by laser ablation in a nozzle plate (24) which has previously been bonded to the body of the printer (16). The laser beam is caused to converge at a point in front of the nozzle plate (24) so that a nozzle is formed which tapers toward the outlet. First and second beam masks (72, 74) are established in front of a focussing lens with the masks being respectively conjugate in the lens with the nozzle inlet and outlet, which are of different shape. The nozzle has a central land (218) which controls the ink meniscus and avoids the ejected drop receiving a sideways kick from the nozzle wall.

Abstract: An inkjet printhead has ink channels separated one from the next by channels walls that are displaceable in response to actuating signals. Groups of adjacent channels are supplied by respective manifolds such that a single displaceable wall bounds channels belonging to adjacent channel groups. A simplification of the construction and manufacture of the printhead results.

Abstract: An inkjet printhead comprises an array of parallel channels separated one from the next by side walls transversely displaceable in response to an actuating signal. Pattern dependent crosstalk is avoided by applying to a channel selected for actuation a signal held at a given non-zero level for a period of length greater than that the length of the period at which the velocity of droplets ejected from said channel is at its maximum and at which the velocity of a droplet ejected from said selected channel is substantially independent of whether or not channels in the vicinity of said selected channel are similarly actuated to effect droplet ejection simultaneously with droplet ejection from the selected channel.

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: A coating on a substrate which endows the substrate with a desired surface property, the coating comprising a cross-linked polysiloxane containing X'-- and X-groups attached to different Si atoms wherein the groups X'-- are monovalent organic groups which provide the desired surface property and the groups X-- are monovalent organic groups which are reactive with a group on the substrate surface and have a higher surface tension than the groups X'--, said coating being bonded to said substrate by reaction of X-groups with substrate surface groups reactive therewith. In one embodiment a non-wetting coating is provided wherein the X'-- group has the formula CF.sub.3 Z-- where Z is a divalent organic group or the formula CH.sub.3 (CH.sub.2).sub.t where t is at least 3.

Abstract: In a method of making an ink jet printhead, corrugations are formed by laser ablation in the bonding surface of a polymer nozzle plate. Adhesive is applied to the micro-cavities thus formed and the nozzle plate is pressed against the end surface of the printhead until the surface lands in the nozzle plate abut on the surface of the printhead.

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 dispersion ink for ink jet printing and which is stable and produces good quality print on plain paper for extended periods of time without the need to interrupt printing to clean the print head, comprises a diluent containing a non-polar component, a pigment and a dispersant for stabilizing the dispersion of the pigment in the diluent, and has a polar solubility parameter greater than 0 but not greater than 7.0 MPa.sup.1/2 and a dewetting velocity of at least 100 .mu.m.sec.sup.-1, measured on a surface having a surface energy of 10.+-.1 mN.m.sup.-1.

Abstract: An ink jet printer ink of the kind comprising a dispersion of a pigment in a non-aqueous diluent wherein the diluent is a single phase liquid comprising a major amount of aliphatic hydrocarbon and a minor amount of a polar component, comprising oleyl alcohol alone or in combination with a least one other polar liquid such as an ether or an ester.