A continuous ink jet printer has a line (69a) for venting at least some of the air that has been sucked along the gutter line (17), and a line (69b) for recirculating back to the printhead (25) at least some of the air that has been sucked down the gutter line (17). Preferably the relative proportions of vented air and recirculated air can be varied, so as to reduce solvent loss during normal operation but allow increased solvent loss if the ink is over-dilute. Preferably the air recirculated to the printhead is connected directly into the flow path from the gutter orifice to the source of gutter suction, without opening into the space containing the ink jet. This reduces the tendency of solvent in the recirculated air condense on the printhead electrodes.