| 摘要 |
Self-cleaning printer with reverse fluid flow and ultrasonics and method of assembling the printer. The printer comprises a print head defining a plurality of ink channels therein, each ink channel terminating in an ink ejection orifice. The print head also has a surface thereon surrounding all the orifices. Contaminant may reside on the surface and also may completely or partially obstruct the orifice. Therefore, a cleaning assembly 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 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 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 is provided to separate the contaminant from the fluid. In addition, a valve system 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 induces pressure waves in the fluid to dislodge the contaminant and thus clean the surface and/or orifice.
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