Domino UK Limited

Richard Thomas Calhoun Bridges

Stuart Mark Walkington

Colin Jon Partridge

Justin Chase

Daniel John Lee

Juergen Martin

Antonio Martin

A continuous inkjet printer () has an ink droplet generator () and a controller () that varies a modulating voltage applied to the ink droplet generator () and measures corresponding breakup times of a jet of ink into ink droplets to obtain a portion of a characteristic of breakup time against modulating voltage. The controller () obtains a variation range, varies the modulating voltage over the variation range to obtain the portion of the characteristic, calculates a gradient from the portion of the characteristic, compares the gradient with a predetermined gradient and, depending on whether the calculated gradient is less than or greater than the predetermined gradient, generates an adjusted variation range that is displaced in a first sense or a second, opposite sense, respectively, relative to the variation range.

Dynamic modulating voltage adjustment

A continuous inkjet printer () having a printhead () that includes first and second ink droplet generators (), each operable to generate a stream () of ink droplets, and a common gutter () arranged to receive unprinted ink droplets from the first and second ink droplet generators (), the printer () further including control means configured to determine receipt into the common gutter () of ink droplets from the first and second ink droplet generators (), wherein the control means are operable to use a single sensor () to determine receipt into the common gutter () of ink droplets from one, both, or neither of the first and second ink droplet generators ().

Common gutter sensing

A print head () for a continuous inkjet printer has an ink drop generator (), an ink supply tube () connected to the ink drop generator (), and a solvent supply tube () connected at a first end to the ink drop generator () and for connection at a second end to a solvent reservoir. The solvent supply tube () is provided with ink flow restriction means () for restricting a flow of ink from the ink drop generator () into the solvent supply tube (). The flow restriction means () comprise an arrangement () of the solvent supply tube () such that, for a flow direction reversing portion () of the solvent supply tube () at the first end of the solvent supply tube (), a flow of solvent from the second end to the first end of the solvent supply tube () flows away from the ink drop generator (). Also a printer including such a print head and a former for use with such a print head.

Solvent supply tube arrangement

A continuous inkjet printer () has an ink drop generator () to generate a stream of ink drops (), deflection means () to direct each drop of the stream of ink drops either to a gutter () or to one of a plurality of default print positions in a stroke direction () on a substrate (), and input means () to receive an indication of an offset. The deflection means, in dependence upon the indication of the offset, direct drops that would otherwise be directed to default print positions to offset print positions on a substrate (), the offset print positions being displaced in the stroke directionby the offset from the default print positions. The input means () may also receive an indication of a print height scaling factor and the deflection means (), in dependence upon the indication of the print height scaling factor, direct drops that would otherwise be directed to default print positions to scaled print positions on a substrate (), the scaled print positions being displaced from the origin in the stroke direction () by displacements corresponding to displacements from the origin of the default print positions when scaled by the print height scaling factor.

Stroke direction offset adjustment

The invention discloses various methods of controlling or monitoring the performance of a continuous inkjet printer based on monitoring vacuum levels and/or noise in the gutter line.

Continuous inkjet printers

A printer () operable to print a message in strokes on a substrate () passing in a print direction () along a moving line (), wherein the printer is operable () to receive an indication of an allowable increase in length in the print direction of a message due to an increase in length in the print direction of gaps between successive strokes printed by the printer, to receive () an indication () of a speed of movement in the print direction of a moving line, to determine from the indication of the speed of movement of the moving line whether an increase in length in the print direction of a message printed by the printer is greater than the allowable increase in length and, if so, to generate an alert.

Printers

The invention provides a method of adding solvent or make-up fluid into the gutter line of a continuous ink printer. During the addition of solvent, the vacuum level in the gutter line is monitored and maintained at a level sufficient to ensure that vacuum is maintained at the gutter. Vacuum level in the gutter line is preferably controlled by controlling the speed of a variable speed gutter pump. Noise in the gutter line is preferably used as a control over pump speed.

Growing community of inventors

Cambridge, United Kingdom

Richard Thomas Calhoun Bridges