US 6,183,057 B2 · Self-cleaning ink jet printer having ultrasonics with reverse flow and method of assembling same

Abstract

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.

Claims30

Dependent claims

A self-cleaning printer, comprising:

(a) a print head having a surface thereon;
(b) a structural member disposed opposite the surface for defining a gap therebetween sized to allow a flow of fluid in a first direction through the gap, the size of the gap controlling hydrodynamic pressure and acceleration of the fluid through the gap to induce a shearing force in the fluid, whereby the shearing force acts against the surface while the shearing force is induced in the fluid;
(c) a junction coupled to the gap for changing flow of the fluid from the first direction to a second direction opposite the first direction, whereby the fluid is agitated while the fluid changes from the first direction to the second direction;
and
(d) a pressure pulse generator in fluid communication with the fluid for generating a pressure wave propagating in the fluid and acting against the surface, whereby the surface is cleaned while the shearing force and the pressure wave act against the surface and while the fluid is agitated.

2 more elements

A self-cleaning printer, comprising:

(a) a print head having a surface defining an orifice therethrough, the orifice susceptible to contaminant obstructing the orifice;
(b) a cleaning assembly disposed proximate the surface for directing a flow of liquid in a first direction along the surface and across the orifice to clean the contaminant from the orifice, said assembly including:
(i) a cup sealingly surrounding the orifice, said cup defining a cavity therein;
(ii) an elongate septum disposed in said cup perpendicularly opposite the orifice for defining a gap between the orifice and said septum, the gap sized to allow the liquid through the gap, said septum dividing the cavity into a first chamber and a second chamber each in communication with the gap, the size of the gap controlling hydrodynamic pressure and acceleration of the liquid through the gap to induce a hydrodynamic shearing force in the liquid, whereby the shearing force acts against the contaminant while the shearing force is induced in the liquid;
(iii) a valve system in fluid communication with the gap for changing flow of the liquid from the first direction to a second direction opposite the first direction to agitate the contaminant;
(iv) an ultrasonic transducer in fluid communication with the liquid for generating a pressure wave propagating in the liquid and acting against the contaminant, whereby the contaminant is entrained in the liquid while the shearing force and the pressure wave act against the contaminant and while the contaminant is agitated and whereby the surface is cleaned of the contaminant while the contaminant is entrained in the liquid;
(v) a pump in fluid communication with the second chamber for pumping the liquid and entrained contaminant from the gap and into the second chamber;
and
(c) a controller connected to said cleaning assembly and said print head for controlling operation thereof.

6 more elements

A method of assembling a self-cleaning printer, comprising the steps of:

(a) providing a print head, the print head having a surface defining an orifice therethrough, the orifice susceptible to contaminant obstructing the orifice;
(b) disposing a cleaning assembly proximate the surface for directing a flow of liquid in a first direction along the surface and across the orifice to clean the contaminant from the orifice, the step of disposing a cleaning assembly including the steps of:
(i) providing a cup for sealingly surrounding the orifice, the cup defining a cavity therein;
(ii) disposing an elongate septum in the cup perpendicularly opposite the orifice for defining a gap between the orifice and the septum, the gap sized to allow the liquid through the gap, the septum dividing the cavity into a first chamber and a second chamber each in communication with the gap, the the size of the gap controlling hydrodynamic pressure and acceleration of the liquid through the gap to induce a hydrodynamic shearing force in the liquid, whereby the shearing force acts against the contaminant while the shearing force is induced in the flow of liquid;
(iii) providing a valve system to be disposed in fluid communication with the gap for changing flow of the liquid from the first direction to a second direction opposite the first direction;
(iv) disposing an ultrasonic transducer in fluid communication with the liquid for generating a pressure wave propagating in the liquid and acting against the contaminant, whereby the contaminant is entrained in the liquid while the shearing force and pressure wave act against the contaminant and while the contaminant is agitated and whereby the surface is cleaned of the contaminant while the contaminant is entrained in the liquid;
(v) disposing a pump in fluid communication with the second chamber for pumping the liquid and entrained contaminant from the gap and into the second chamber;
and
(c) connecting a controller to the cleaning assembly and the print head for controlling operation thereof.

6 more elements

Dependencies are inferred from the claim text.

Self-cleaning ink jet printer having ultrasonics with reverse flow and method of assembling same

Life of this patent

Self-cleaning ink jet printer having ultrasonics with reverse flow and method of assembling same

Life of this patent

Abstract

Claims30