Abstract: There is provided a continuous inkjet printer for printing onto an external substrate that moves past the printer. The printer comprising: a print head. The print head comprising: a nozzle for generating and ejecting a stream of ink droplets for printing; at least one electrode for guiding the stream of ink droplets; and a gutter for receiving droplets of ink which are not used for printing. The printer comprising an ink system for storing ink and supplying ink to the print head, the ink system comprising a gutter pump in fluid communication with the gutter. The print head is fluidly coupled to the ink system via a plurality of fluid conduits, the plurality of conduits comprising a main return line; and a portion of the main return line which extends between the gutter and the gutter pump has a length of no more than 1 metre.