Abstract: In a color printhead, print elements for different colors print swaths of pixels in different colors side by side in a first traverse; the printhead and the surface to be printed are indexed, and in the next traverse, further swaths are printed with each new swath overlapping a previous swath in a different color.

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: An ink jet or other printer serves to print for each row of input pixels, two superimposed rows of contiguous “super pixels,” each print pixel being capable of receiving print contributions from N super pixels. The super pixels are twice the width of the input pixels and one row of super pixels is offset by half a super pixel width from the next row of super pixels. Redundancy is thus provided against the loss of a print element. The effects of smoothing or an image are reduced by edge enhancement processes.

Abstract: A method of manufacturing an ink jet print head includes the steps of bonding a body of piezoelectric material to a base plate and cutting channels into the piezoelectric material to form ink chambers which are actuated by applying voltages to electrodes provided on surfaces of the chambers. The base plate carries IC's which contain the drive circuitry for actuating the ink chambers. To ensure reliable electrical connection between the chamber electrodes and the IC's, the electrodes and conducting tracks on the base plate are formed in a single step by depositing a conductive layer over both the PZT body and the base plate. A step of masking or selective removal of material may be performed to achieve the necessary patterning of the electrodes and tracks.

Abstract: In a fluid pumping apparatus suitable for use in drop on demand ink jet printing, a resiliently deformable chamber wall is acted upon to create acoustic waves, which in turn cause a fluid flow in a chamber outlet. The resiliently deformable chamber wall preferably includes both rigid and flexible portions. In an alternative arrangement a channel wall is provided with a region moveable in an actuation direction. An electromagnetic actuator operates under the principle of flux modulation. The invention is preferably of planar construction, manufactured using MEMS techniques.

Abstract: A nozzle in a nozzle plate for an inkjet printhead is formed by directing a laser beam at a nozzle plate. Accurate control of the divergence of the beam is achieved by splitting the beam into sub-beams, each sub-beam having divergence with an origin lying apart from the point at which the beam is created by splitting, and thereafter recombining the sub-beams. Greater accuracy in the taper and inlet shape of the manufactured nozzle is thereby obtained.

Abstract: Data input to an ink jet printer is subjected to a transformation which is the inverse of a transformation representing the errors in ink drop placement which have been measured for that specific ink jet printer.

Abstract: An inkjet printer has a print head unit with four parallel rows of nozzles each row being able to receive an ink of a different color. The length of each row is less than the length of the print head unit. A number of print head units may be aligned together to provide elongate arrays of nozzles. The nozzle spacing along the array is non-uniform in that the inter-nozzle spacing within the rows is less than the inter-row spacing between neighboring print head units. In operation each print head unit deposits a non-contiguous swath on the paper and then all the units are moved an equal distance and a further swath printed thereby interleaving the swaths. A method of supplying ink and an ink supply member are also provided.

Abstract: A hollow cylindrical support for a plurality of flow-through inkjet print heads has two folded wall sections cooperating to define elongate inlet and outlet ink manifolds, one wall section being thermally conducting so as to promote heat transfer along the length of the support, the other wall section being thermally insulating so as to inhibit heat transfer between the inlet and outlet manifolds. The thermally insulating section serves to trap a boundary layer of fluid, for example in a cavity wall or cellular material.

Abstract: An ink supply system for a droplet deposition apparatus wherein the pressure at the nozzle is controlled by a remote point, said remote point being positioned in parallel with said print head. The flow restrictions in the printhead arm and the pressure control arm of the circuit being selected to achieve this.

Abstract: An ink jet printer with ink flowing through an ink chamber and over an ink ejection port leading to a nozzle has a deflection surface such as a chamfer at the junction of the chamber and the ejection port to inhibit debris from entering the port.

Abstract: Droplet deposition apparatus comprises a fluid chamber comprising an actuator actuable by electrical signals to effect ejection of droplets from the fluid chamber, a drive circuit for supplying the electrical signals; and a conduit for supplying droplet fluid to said fluid chamber, the drive circuit being in substantial thermal contact with the conduit so as to transfer a substantial part of the heat generated in the drive circuit to the droplet fluid.

Abstract: A nozzle plate includes a body and an insert formed of polymeric material. Each nozzle has an inlet, an outlet, and a bore extending between the inlet and the outlet and formed through the polymeric material of the insert located within an aperture formed in a body of the nozzle plate.

Abstract: An inkjet printhead is formed by a multistage process: Grooves are formed on the base of a block of piezoelectronic material, and a conductor applied thereto. Conducting tracks are deposited on a substrate with matching spacing, such that the base and piezoelectric material can be joined giving a desired electrical connection. Channels are cut into the top of teh piezoelectric block to intersect with the grooves, forming ink chambers, and these are provided with electrodes in electrical contact with the tracks.

Abstract: Data input to an ink jet printer is subjected to a transformation which is the inverse of a transformation representing the errors in ink drop placement which have been measured for that specific ink jet printer.

Abstract: A vacuum drum assembly for a printing machine has a drum with an array of passageways distributed along its length and around its periphery. The passageways permit air to flow from outside the drum to inside the drum in response to reduced air pressure inside the drum. The assembly also has an array of valve members, each valve member being movable between a closed position in which that valve member restricts at least one of the passageways and an open position in which the restriction of that passageway or those passageways is reduced. The assembly is arranged such that, when a partial area of the drum is wrapped with a sheet of material, at least some of the valves for the passageways adjacent the edges of that area are open, and the valves for the passageways which are not covered by the sheet and are not adjacent the edges of that area are closed.

Abstract: In ink jet printing, a UV curable undercoat is first deposited on a substrate. The ink and undercoat are cured together. The thickness of the undercoat varies inversely with the thickness of the ink, so that a flat print surface is achieved. Application of an undercoat may be disabled on text material, to preserve edge definition.

Abstract: In droplet deposition apparatus comprising one or more independently actuable ink ejection chambers, electrical signals are applied to reduce variation in the temperature of the droplet fluid between chambers and with variations in droplet ejection input data. Short potential difference pulses, suitable for influencing the temperature of the droplet fluid in a chamber, can be generated by application of longer duration voltages to ink chamber actuation means.

Abstract: A drop-on-demand piezo-electric printhead has channel walls defined by piezo-electric material (10) with electrodes (26) along the length thereof. In portions of the channels which are open to an ink supply conduit, the piezo material is locally disabled, e.g. by reducing the width of the electrode or by interposing a material (40) of lower dielectric constant between the electrode and the piezo material. A lower capacitive load results.

Abstract: A method for prevention of nozzle plate peel for inkjet printheads. The nozzle plate is bonded to the nozzle, with a layer of adhesive, and to a support, with a thicker layer of adhesive. This extra support prevents the peeling of the nozzle plate under the forces generated by, for example, a wiper blade passing over it. Spacers between the nozzle plate and support ensure the correct uniformity and constant thickness of the adhesive layer.