Ink jet print head with water protection

A continuous ink-jet printer comprising a print head comprising:

• a cavity for circulating at least one ink jet, delimited by lateral walls,
• at least one nozzle for producing at least one ink jet in said cavity,
• at least one electrode for electrostatically separating drops or sections of one or more of said jet intended for printing from drops or sections that do not serve for printing,
• a slot, open on the outside of the cavity or of the print head for an exit of drops or sections of ink intended for printing,
• at least one gutter for recovering drops or sections not intended for printing, said ink-jet printer further comprising:
• a circuit that generates and circulates dry air along an inlet part of said slot or an outlet part of said slot to prevent atmospheric humid air from outside the print head from flowing into the print head,
• a recirculation circuit for recirculating air extracted from said cavity, said recirculation circuit providing a flow of recirculated air reinjected into said cavity.

A continuous ink-jet printer comprising a print head comprising:

• a cavity for circulating at least one ink jet, delimited by lateral walls,
• at least one nozzle for producing at least one ink jet in said cavity,
• at least one electrode for electrostatically separating drops or sections of one or more of said jet intended for printing from drops or sections that do not serve for printing,
• a slot, open on the outside of the cavity or of the print head for an exit of drops or sections of ink intended for printing,
• at least one gutter for recovering drops or sections not intended for printing,
• said ink-jet printer further comprising:
• a circuit that generates and circulates dry air along an inlet part of said slot or an outlet part of said slot to prevent atmospheric humid air from outside the print head from flowing into the print head, said circuit comprising at least a generator of dry air for generating dry air, said dry air having a water vapor pressure lower than the water vapor pressure defined by 100% relative humidity at the coldest temperature of the printer, along at least part of the outlet slot of said cavity or of said print head.