A self-cleaning ink jet printer with reverse fluid flow and ultrasonics and method of assembling the printer

摘要

Self-cleaning printer with reverse fluid flow and ultrasonics and method of assembling the printer. The printer (10) comprises a print head (60) defining a plurality of ink channels (70) therein, each ink channel terminating in an ink ejection orifice (85). The print head also has a surface (90) thereon surrounding all the orifices. Contaminant (140) may reside on the surface and also may completely or partially obstruct the orifice. Therefore, a cleaning assembly (170) is disposed relative to the surface and/or orifice for directing a flow of fluid along the surface and/or across the orifice to clean the contaminant from the surface and/or orifice. The cleaning assembly includes a septum (210) disposed opposite the surface or orifice for defining a gap therebetween. Presence of the septum accelerates the flow of fluid through the gap to induce a hydrodynamic shearing force in the fluid. This shearing force acts against the contaminant to clean the contaminant from the surface and/or orifice. A pump (290) in fluid communication with the gap is also provided for pumping the fluid through the gap. As the surface and/or orifice is cleaned, the contaminant is entrained in the fluid. A filter (300, 310) is provided to separate the contaminant from the fluid. In addition, a valve system (380) in fluid communication with the gap is operable to direct flow of the fluid through the gap in a first direction and then in a second direction opposite the first direction to enhance cleaning effectiveness. Moreover, an ultrasonic transducer (245) induces pressure waves in the fluid to dislodge the contaminant and thus clean the surface and/or orifice. <IMAGE>