Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-11-12
2002-12-10
Hilten, John S. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06491375
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to printheads used with ink printers. It finds particular application in conjunction with printheads used with acoustic ink printers, and will be described with particular reference thereto. It will be appreciated, however, that the invention will also find application in printheads used with other types of ink printers, and the like.
In acoustic ink printing, acoustic radiation by an ejector is used to eject individual droplets on demand from a free ink surface (i.e., the Liquid/air interface). Typically, several ejectors are arranged in a linear or two-dimensional array in a printhead. The ejectors eject droplets at a sufficient velocity in a pattern so that the ink droplets are deposited on a nearby recording medium in the shape of an image.
Heretofore, acoustic ink printheads incorporate several different components. More specifically, they incorporate electrical components to supply power to the printhead, acoustic components to produce the acoustic radiation within the printhead, structural components to define and maintain the framework of the printhead, and fluidic components to flow ink, coolants, and/or other liquids through the printhead.
In conventional printheads, each of the components is a separate and independent element. Each of the independent components is combined to form a stand-alone printhead.
To illustrate the component-based design of the conventional printhead, one method of producing a traditional printhead is discussed. The first step includes stamping different hole patterns into several pieces of two-dimensional sheet metal. The two-dimensional metal sheets are then stacked on top of one another in an aligned design. The sheets are secured to one another using a brazed metal, thereby creating a three-dimensional structure. A glass acoustic transducer, an aperture plate, along with fluidic components and connections, are then secured to the three-dimensional structure. Wires are bonded into the structure and electrical connections are made to allow the printhead to communicate with external devices. Traditionally, the electrical connections include polyimide/copper flex, which is epoxied to the head. Wire bonds between the flex and the chips on the glass complete connections to the glass transducers.
Building printheads according to the method discussed above, which merely combines various discrete components, has at least one drawback. For example, because the reliability of the printhead is dependent upon the reliability of each of the components, the reliability of the printhead is negatively affected if any one of the components is defective. Furthermore, the number of component parts in the conventional printhead adds to the complexity and cost of the manufacturing process and, consequently, the final product.
The present invention provides a new and improved apparatus and method which overcomes the above-referenced problems and others.
SUMMARY OF THE INVENTION
An integrated printhead includes a housing and a reservoir defined in the housing. The reservoir contains a first fluid. A plate covers an open side of the reservoir. The plate has apertures for passing the first fluid from the reservoir to the exterior of the housing. A passage is formed within the housing. The passage communicates with the reservoir. A temperature sensor within the housing measures a temperature of the first fluid. A substrate, within the reservoir, causes the first fluid to be ejected from the reservoir.
In accordance with one aspect of the invention, the housing includes a ceramic material.
In accordance with another aspect of the invention, an acoustic generator, secured to the substrate, produces acoustic sound waves within the reservoir. At least one lens, secured to the substrate, focuses the acoustic sound waves toward the aperture plate. Each lens is associated with one of the acoustic generators.
In accordance with another aspect of the invention, electronics are integrated into the housing.
In accordance with a more limited aspect of the invention, an electrical connection is used for testing the electronics.
In accordance with another aspect of the invention, a second reservoir contains a gas and a portion of the fluid. The gas acts as a dampener for absorbing vibrations and shocks in the fluid.
In accordance with another aspect of the invention, a second cover surrounds the substrate. A second fluid passes through apertures in the second cover for cooling the first fluid.
In accordance with another aspect of the invention, a pressure sensor measures a pressure of the first fluid.
In accordance with another aspect of the invention, a temperature controller device, electrically connected to the temperature sensor, controls a temperature of the first fluid as a function of data received from the temperature sensor.
In accordance with another aspect of the invention, a flow controller controls a flow of the first fluid as a function of data received from a flow sensor.
One advantage of the present invention is that the number of parts within the acoustic ink printhead is reduced.
Another advantage of the present invention is that the manufacturing cost of the acoustic ink printhead is reduced.
Another advantage of the present invention is that the performance of the acoustic ink printhead is improved.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
patent: 4347524 (1982-08-01), Engel et al.
patent: 4415910 (1983-11-01), Reece
patent: 5612723 (1997-03-01), Shimura et al.
patent: 5684519 (1997-11-01), Matoba et al.
patent: 6074043 (2000-06-01), Ahn
patent: 6154236 (2000-11-01), Roy et al.
patent: 6315394 (2001-11-01), Fujii
Fay Sharpe Fagan Minnich & McKee LLP
Feggins K.
Hilten John S.
Xerox Corporation
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