A flexographic printer is provided with: a printing plate for transferring ink at an ink transfer site to an object to be printed S; an anilox roll for supplying ink to the printing plate at an ink supply site; a plate cylinder on which the printing plate is wound and rotated; and an ink solvent supply unit for supplying a solvent for the ink on the surface of the printing plate in a post-ink transfer region that is downstream of the ink transfer site in the plate cylinder rotation direction and upstream of the ink supply site in the plate cylinder rotation direction.

There is disclosed an ultrasonic cleaning bar for cleaning a roller of a printing machine. The ultrasonic cleaning bar comprises: an elongate body defining a longitudinal axis; a doctor blade supported by the body; an ultrasonic transducer for generating ultrasonic waves within the cleaning fluid; and first and second formations positioned at longitudinally opposite ends of the body, the first formation being releasably engageable with a first mounting bracket of the printing machine and the second formation being releasably engageable with a second mounting bracket of the printing machine; and wherein, when the first and second formations are engaged with the first and second brackets, the doctor blade engages a surface of the roller, such that the body, the doctor blade and the roller define a trough therebetween configured to contain a cleaning fluid which contacts the roller.

There is provided a method of cleaning a print roller and a system for performing the same. The method comprises providing an ultrasonic cleaning bar having at least one ultrasonic energy source. The ultrasonic cleaning bar is engaged with an ink-carrying surface of the print roller, the ultrasonic cleaning bar and the ink-carrying surface defining a trough therebetween for containing a cleaning fluid. A cleaning routine is executed, the cleaning routine comprising: filling the trough with the cleaning fluid so that the cleaning fluid contacts the ink-carrying surface; activating the ultrasonic energy source for a period of time to remove contaminants from the ink-carrying surface of the print roller so that the contaminants become suspended in the cleaning fluid; and draining the suspension of cleaning fluid and contaminants from the trough. The method comprises executing the cleaning routine at least two times in succession before cleaning of the print roller is complete.

There is provided a method of cleaning a print roller and a system for performing the same. The method comprises providing an ultrasonic cleaning bar having at least one ultrasonic energy source. The ultrasonic cleaning bar is engaged with an ink-carrying surface of the print roller, the ultrasonic cleaning bar and the ink-carrying surface defining a trough therebetween for containing a cleaning fluid. A cleaning routine is executed, the cleaning routine comprising: filling the trough with the cleaning fluid so that the cleaning fluid contacts the ink-carrying surface; activating the ultrasonic energy source for a period of time to remove contaminants from the ink-carrying surface of the print roller so that the contaminants become suspended in the cleaning fluid; and draining the suspension of cleaning fluid and contaminants from the trough. The method comprises executing the cleaning routine at least two times in succession before cleaning of the print roller is complete.

A printing screen for printing deposits of a print medium onto workpieces, the printing screen comprising a sheet in which a pattern of printing apertures are formed to allow for printing of a pattern of deposits onto a workpiece, and a waveguide which can be driven to induce an ultrasonic vibration in the sheet, wherein the waveguide comprises an elongate body at a surface of the sheet which at least partially surrounds the pattern of printing apertures.

A flexographic printer is provided with: a printing plate for transferring ink at an ink transfer site to an object to be printed S; an anilox roll for supplying ink to the printing plate at an ink supply site; a plate cylinder on which the printing plate is wound and rotated; and an ink solvent supply unit for supplying a solvent for the ink on the surface of the printing plate in a post-ink transfer region that is downstream of the ink transfer site in the plate cylinder rotation direction and upstream of the ink supply site in the plate cylinder rotation direction.

A cleaning liquid for a liquid ejecting apparatus to be fed into liquid channels of a liquid ejecting apparatus contains at least a water-soluble organic solvent, a silicone surfactant, and an acetylenic diol surfactant. At least part of the inner surfaces of the liquid channels is made from a fluorine-based material.

There is disclosed an ultrasonic cleaning bar for cleaning a roller of a printing machine. The ultrasonic cleaning bar comprises: an elongate body defining a longitudinal axis; a doctor blade supported by the body; an ultrasonic transducer for generating ultrasonic waves within the cleaning fluid; and first and second formations positioned at longitudinally opposite ends of the body, the first formation being releasably engageable with a first mounting bracket of the printing machine and the second formation being releasably engageable with a second mounting bracket of the printing machine; and wherein, when the first and second formations are engaged with the first and second brackets, the doctor blade engages a surface of the roller, such that the body, the doctor blade and the roller define a trough therebetween configured to contain a cleaning fluid which contacts the roller.

A printing screen for printing deposits of a print medium onto workpieces, the printing screen comprising a sheet in which a pattern of printing apertures are formed to allow for printing of a pattern of deposits onto a workpiece, and a waveguide which can be driven to induce an ultrasonic vibration in the sheet, wherein the waveguide comprises an elongate body at a surface of the sheet which at least partially surrounds the pattern of printing apertures.