Xaar Technology Limited

Arrayjet Limited

Howard John Manning

Stephen Temple

Robert Alan Harvey

Michael John Dixon

Salhadin Omer

Keith P Butler

Jerzy Marcin Zaba

Paul Raymond Drury

Christopher D Philips

Steven Temple

Steve Temple

Peter Stanier

Benjamin Bruce Mitchell

Inkjet printhead with an array of ejection chambers spaced in an array direction, each communicating with an ink orifice, inlet and outlet plenum chambers communicating with the ejection chambers, and inlet and outlet manifolds extending in the array direction and communicating with the plenum chambers through a porous sheet. While there are substantial net ink flows in the array direction in the inlet and the outlet manifolds, there is substantially no net flow in the array direction in the inlet or outlet plenum chamber. Ink pressure is therefore constant over the array of ejection chambers.

Droplet deposition apparatus

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.

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.

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.

Droplet deposition apparatus comprises an array of fluid chambers, each chamber communicating with an orifice for droplet ejection, a common fluid inlet manifold and a common fluid outlet manifold, and means for generating a fluid flow into the inlet manifold, through each chamber in the array and into the outlet manifold, the fluid flow through each chamber being sufficient to prevent foreign bodies in the fluid from lodging in the orifice. Each chamber is associated with means for effecting droplet ejection from the orifice simultaneously with the fluid flow through the chamber. The resistance to flow of one of the inlet and outlet manifolds is chosen such that the pressure at a fluid inlet to any chamber in the array varies between any two chambers by an amount less than that which would give rise to significant differences in droplet ejection properties between these two chambers.

A method is described of operating an ink jet printhead having one or more manifolds each connected to more than one chamber, each chamber being associated with a nozzle and capable of ejecting drops therefrom: a number of different liquids larger than the number of manifolds is introduced into the printhead via the nozzles; and the volume of the liquid subsequently printed from each nozzle is less than the volume of the chamber associated with that nozzle, and also less than the volume of liquid introduced into that chamber. By this means the printhead prints more different liquids than is conventionally possible without mixing them.

Highly parallel fabrication of microarrays by ink jet printheads

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.

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.

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.

Vacuum drums for printing, and duplex printers

A vacuum drum assembly for a printing machine has a drum with an array of passageways distributed along its length and around its periphery to permit airflow from outside the drum to inside the drum in response to reduced air pressure inside the drum. An array of valves are movable between a closed position in which that valve restricts at least one of the passageways and an open position in which the restriction of the same passageways is reduced. When a partial area of the drum is wrapped with a sheet of material, at least some of the passageway valves adjacent the edges of that area are open, and the valves for the passageways not covered by the sheet and not adjacent the edges of that area are closed. The drum open area is regulated to be small in regions where there is no paper. Accordingly, the open area of the drum is adapted to the paper shape and size and the paper position on the drum, while minimizing the required suction flow. A duplex printing machine has two such vacuum drum assemblies with their drums parallel. The air pressure inside the drums is reduced and the drums are counter-rotated. Printing material is fed to the first drum and held on the first drum by vacuum and rotated therewith. A first print head prints on one side of the material. The material is released from the first drum in a direction towards the second drum and held on the second drum by vacuum and rotated therewith. A second print head then prints on the material on the second drum. The material is then released from the second drum.

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Edinburgh, United Kingdom

Howard John Manning