Continuous inkjet printer

A continuous inkjet printer comprising:

• an ink supply system;
• a droplet generator configured to receive ink from the ink supply system and to produce a jet of ink for printing;
• a gutter configured to receive parts of the jet that are not required for printing;
• a gutter line connected to the gutter and configured to return unprinted ink to the ink supply system;
• a suction system comprising a Venturi having a suction port configured to apply a suction force to the gutter line;
• and
• a gutter flow rate control system configured to control a rate of flow of fluid along the gutter line, the gutter flow rate control system comprising a controllable fluid path configured to allow ink to flow from a first location within the printer to a second location in fluid communication with the suction port of the Venturi such that an amount of suction force is changed based on delivery of the ink from the ink supply system to the suction port of the Venturi via the controllable fluid path.

A method comprising:

• operating a continuous inkjet printer that includes,
• an ink supply system;
• a droplet generator configured to receive ink from the ink supply system and to produce a jet of ink for printing;
• a gutter configured to receive parts of the jet that are not required for printing;
• a gutter line connected to the gutter and configured to return unprinted ink to the ink supply system;
• and
• a suction system comprising a Venturi having a suction port configured to apply a suction force to the gutter line, the suction system having a first suction configuration and a second suction configuration;
• wherein operating the continuous inkjet printer comprises,
• controlling a rate of flow of fluid along the gutter line based on temperature,
• wherein
• controlling the rate of flow of fluid along the gutter line based on temperature comprises causing the suction system to operate in the first suction configuration at a first temperature, and to operate in a second suction configuration at a second temperature, the first temperature being higher than the second temperature;
• and
• wherein the first suction configuration and the second suction configuration are configured such that if the suction system was caused to operate in the first suction configuration at the second temperature, the rate of flow of fluid along the gutter would be greater than the rate of flow of fluid along the gutter when the suction system is caused to operate in the second suction configuration at the second temperature.