Cleaning system and method

A system for cleaning a print roller, comprising:

• an ultrasonic cleaning bar having at least one ultrasonic energy source, wherein the ultrasonic cleaning bar is engageable with an ink-carrying surface of a print roller to define a trough therebetween for containing a cleaning fluid;
• an outlet valve to control the flow of fluid leaving the trough;
• and
• a control unit;
• wherein the control unit is configured to execute a cleaning routine, the cleaning routine comprising:
• filling the trough of the ultrasonic cleaning bar 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;
• maintaining the outlet valve in a closed configuration to prevent cleaning fluid draining from the trough whilst the ultrasonic energy source is activated;
• and
• draining the suspension of cleaning fluid and contaminants from the trough;
• wherein the control unit is configured to execute the cleaning routine at least two times in succession before cleaning of the print roller is complete.