Abstract: An ink jet ink is disclosed which comprises a binder, a colorant, a conductivity controller and a liquid vehicle in which at least the binder and colourant are soluble, the binder being a nitrocellulose having a viscosity of 15 centipoise or less as measured by method 1 herein; or a weight average molecular weight of not more than 25,000 as measured by method 3 herein; or the nitrocellulose has both the said viscosity and the said weight average molecular weight;and in that the nitrocellulose has a nitrogen content of at least 9.5% by weight as measured by the method of ASTM D 301-72;and in that the ink has a viscosity of 1.6 to 4 centipoise at 25.degree. C. using a Brookfield DV-11+ viscometer with a number 00 spindle at 60 r.p.m (method 2 herein).

Abstract: A method of making an electrode assembly for a continuous ink jet printer. The method includes disposing a plurality of conductive tracks side by side on a flexible non-conductive film, each of said conductive tracks having an electrode portion, a conductor portion and a connector portion. The film is mounted on a support block with the electrode portion of each conductive track disposed at an end surface of the block.

Abstract: A method of printing with a multi-nozzle continuous ink jet printer 1 that has a row of nozzles through which respective streams of ink 3 are emitted before being broken up into columns of droplets, a charge electrode assembly has a plurality of charge electrodes for charging individual droplets in each of the columns of droplets, deflection electrodes 5, 6 for deflecting charged droplets according to the charge thereon and an auxiliary charge electrode 8. A compensating charge is applied to all droplets in a chosen row by the auxiliary charge electrode causing differential deflection that allows drops from adjacent rows of droplets printed in alignment rather than offset from one another.

Abstract: A print head for a continuous ink jet printer has a nozzle through which ink is emitted and broken up into droplets under the action of a piezoelectric oscillator. A charge electrode applies charge to selected droplets and a deflection electrode deflects the path of the charged droplets to cause printing on a substrate. A gutter collects droplets which are not required for printing. A charge electrode, together with one of the deflection electrodes is movable in a direction transverse to the path of the droplets selectively under the action of pressurized ink fed from an ink supply. Similarly, the gutter is movable in the same way by another actuator.

Abstract: An armature (1) for an actuator drive for a multi-jet continuous ink jet printhead has, at one side, a row of transducer mountings (10). The armature (1) has a plurality of elongate slots (5) therethrough in a row parallel to the one side, each slot (5) extending away from the one side and being aligned intermediate to the transducer mountings (10), whereby lands (6) between the slots (5) are aligned with the transducer mountings (10).

Abstract: The invention relates to a multi-channel RF-excited gas laser device which has an elongate tubular dielectric housing 1. The housing has a common elongate ground electrode 2 therein and a plurality of laser channels 4 defined within and extending along the ground electrode 2 adjacent to an interior surface 3 of the dielectric housing. A laser gas is provided within the dielectric housing and a plurality of RF electrodes 7 are disposed adjacent to and extending along an external surface 8 of the dielectric housing 1. Each RF electrode 7 is disposed in registration with one of the laser channels 4.

Abstract: A print head for a continuous ink jet printer has a nozzle 5 through which ink is emitted and broken up into droplets under the action of a piezoelectric oscillator. A charge electrode 3 applies charge to selected droplets and a deflection electrode 4 deflects the path 20 of the charged droplets to cause printing on a substrate. A gutter 6 collects droplets which are not required for printing. A charge electrode 3, together with one of the deflection electrodes 4 is movable in a direction transverse to the path of the droplets selectively under the action of pressurised ink fed from an ink supply 14. Similarly, the gutter 6 is movable in the same way.

Abstract: A pump (1) has a rotor (4) and a stator (3) disposed closely adjacent to and biased towards it, but spaced apart from a surface of the rotor. The stator (3) or rotor (4) has recesses (30) on its surface facing the rotor or stator respectively, and an inlet to and an outlet from each recess to provide for the supply of fluid to and from the recess. Rotation of the rotor (4) about its axis is arranged to cause fluid to be pumped from the inlet to the outlet as a result of the viscous drag on the fluid resulting from rotation of the rotor relative to the stator (3). The force biasing the rotor (4) and stator (3) together is provided at least in part by fluid pressure feedback from the pump (1) in order to control the clamping or biasing pressure between the rotor and stator automatically.

Abstract: A printhead (1) for an ink jet printer includes a chamber (5) for containing marking fluid fed to the head in use. A plurality of orifices (8) open from the chamber (5), a marking fluid being emitted in use through the orifices (8). A corresponding plurality of actuators are provided. Each actuator comprises an arm (12) having at one end means for selectively opening and closing a respective orifice (8); a magnetic circuit (12, 13, 14, 15) of which the arm (12) forms a side; and one or more coils (14) for selectively inducing a magnetic flux in the circuit in order to move the arm (12) between a position in which it closes the respective orifice (8) and a position in which it opens the orifice (8).

Abstract: A galvanometer optics assembly includes a housing which has a laser beam input which is optically coupled to the laser beam output of the laser marking apparatus, a first laser beam output and a second laser beam output, a stationary mirror which is fixedly coupled to the housing and is optically coupled to the laser beam input of the housing, a galvanometer mirror which is rotatively coupled to the housing and is optically coupled to the stationary mirror, a galvanometer optics motor which has a shaft which is fixedly coupled to the galvanometer mirror so that the galvanometer mirror may be optically coupled to either the first laser beam output or the second laser beam output and a galvanometer controller which is electrically coupled to the galvanometer optics motor. The galvanometer optics assembly is for use with a laser marking apparatus which includes a housing and and a laser beam output which is optically coupled to the lasers.

Abstract: Ink jet inks are disclosed comprising a liquid vehicle which is preferably a blend of ethanol and water in a weight ratio of 23/70 (equivalent to 30/70 by volume) to 71/10 (equivalent to 90/10 by volume), a binder, which comprises a sugar or a sugar alcohol or a mixture thereof, preferably a mixture of sorbitol and maltitol, which is soluble in the liquid vehicle, a colorant which is soluble in the liquid vehicle and a surfactant comprising 90% or more of phosphatidylcholine or lysophosphatidylcholine, which is soluble in the liquid vehicle.

Abstract: A continuous ink jet printer has a nozzle plate 1 which includes an orifice 3 for emitting a stream of ink. A counterbore 4 surrounds the orifice. A passage 5, 6 is provided which lies substantially in the plane of the plate and intersects the counterbore, and through which a flow of cleaning agent may be supplied to the counterbore, in order to flush ink from the surrounds of the orifice.

Abstract: There is provided an ink jet ink comprising a binder, a colourant, a liquid vehicle and an adhesion promoter, the adhesion promoter being an alkoxysilane polyalkylene-imine containing repeat units of the formula (I): ##STR1## wherein R.sup.5 represents a bond to another nitrogen atom and R.sup.4 represents a bond to another carbon atom or a hydrogen atom; a is from 1 to 8; b is 1 to 8; c is from 1 to 6; at least one of R.sup.1, R.sup.2 and R.sup.3 is a C.sub.1 -C.sub.6 alkoxy group and any of R.sup.1, R.sup.2 and R.sup.3 which are not alkoxy groups are C.sub.1 -C.sub.6 alkyl groups and p is 1 or more, and x is 1-50.

Abstract: An ink jet printer or a pen has a nozzle or valve (4) formed by an orifice in an elastic material (1), and the orifice comprising a slit or hole (9) in the elastic material deformable to cause the slit or hole to open or close to eject ink (2) under pressure. The printer preferably has plural, closely spaced nozzles and actuators in the form of a piezoelectric unimorph (10).

Abstract: A continuous ink jet printer printhead having an ink channel that is fed by an oscillator to a nozzle connected to the ink channel. A closer is connected within the printhead to close off the nozzle when the continuous jet ink printer is not in use.

Abstract: An ink supply system for a continuous ink jet printer gun body must allow solvent to be added during printing, and known systems are complex, requiring a pair of pumps, the output pressure of at least one of which is critical. Accordingly, to overcome these problems, an ink supply system for such a printer comprises a pump (9) for pressurising ink and air received from a gutter (8) of the printhead to a pressure above that required for ejection of the ink from the gun body (10) and an ink reservoir (1) from which fresh ink may be fed to the pump (9). The system has first (12) and second (19) chambers in combination with air space (13) and valves (14,15,25), provided for maintaining pressurised air above ink in the first chamber (12) and for controlling the pressure of air above ink in the second chamber (19). Conduit (21) is provided for supplying ink from the second chamber (19) to the printhead.

Abstract: A printhead (1) for a continuous ink jet printer has a single pair of nozzles (3,3'). One or more oscillators for vibrating the ink (3,3') may be used to break up the twin streams (4,4') of droplets issuing from the nozzles. A pair (5) of charging gates is provided for applying, selectively and respectively, a charge to droplets in the two streams (4,4'). A pair of deflector means (7) apply respective electric fields across the streams (4,4') to deflect the droplets individually in accordance with the charge thereon. A gutter (10) or pair of gutters (11,11') receive droplets from the respective streams if they are not charged. The arrangement is such that the two streams of droplets are deflected in opposite directions so as to be printed.

Abstract: A two-stage pump (9) for a continuous ink jet printing system comprises a first stage (A) which includes a chamber (91,92) having an inlet (93) and an outlet (94) via a non-return valve (115) to a channel (95). The first stage chamber (91,92) is divided by a dished diaphragm (101) movable by a first cylinder (97) mounted on a pump shaft (98). The pump (9) has a second stage (B) comprising a chamber (104,105) having an inlet (106) from the channel (95) and an outlet (107). The second stage chamber (104,105) is divided by a rolling diaphragm (116) movable by a second cylinder (108) mounted on a pump shaft (98). The cylinders (97,108) are arranged to be driven, and thus drive their respective diaphragms (101,116), 180.degree. out of phase so that ink and air enters the first stage chamber (91,92), is pressurised by the first cylinder (97) and passed through the channel (95) to the second stage chamber, and is further pressurised and passed out of the outlet (107) of the second stage chamber (104,105).

Abstract: An ink-jet ink comprises a colorant and a liquid phase consisting essentially of polymerizable monomers. For continuous printing, the ink also includes a conductive component that is soluble in the liquid phase. No methanol, ethanol, MEK or other such low molecular weight organic solvent is required.

Abstract: A printhead for a continuous ink jet printer has a body with a circular recess in an end face thereof. A circular piezoelectric transducer is disposed in the recess so as to provide a short ink chamber adjacent the face of the body and the piezoelectric transducer is arranged to expand and contract in the direction of its axis when an excitation voltage is applied to it. An ink feed channel connects with the recess for feeding ink to the ink chamber and a nozzle plate is detachably mounted on the end face of the body to eject ink under pressure when the piezoelectric transducer is actuated.