Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including an additional nonwoven fabric
Reexamination Certificate
2002-04-29
2004-10-26
Shewareged, B. (Department: 1774)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including an additional nonwoven fabric
C442S402000, C442S407000, C347S031000, C347S035000, C347S036000
Reexamination Certificate
active
06809047
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed generally to an ink absorber for use primarily in an ink jet printer. More particularly, the present invention is directed to a composite non-woven material for use as an ink-absorber in an ink jet printer. More specifically, the present invention is directed to a composite non-woven needlefelt for use as an ink absorber in an ink jet printer. The composite non-woven ink absorber has a low density/coarse denier top layer and a high density/fine denier bottom layer wherein denier is understood to be the weight-per-unit-length measure of the fiber. The composite non-woven ink absorber of the present invention provides for uniform and efficient absorption and transportation of ink from the top surface of the top layer to the body of the bottom layer of the composite non-woven material.
DESCRIPTION OF PRIOR ART
In ink jet printing devices, the print head typically includes one or more ink filled channels, each with a relatively small ink supply chamber at one end and having an opening, referred to as a nozzle, at the opposite end. Ink droplets are formed and are discharged onto a substrate to be printed. To prevent the nozzles from becoming clogged with dried residual ink droplets, the nozzles are thoroughly flushed with additional ink jet droplets after use. Alternatively, a vacuum may be created within the nozzles, which removes all residual ink prior to any further printing operations. The waste ink generated by either the flushing or vacuuming procedure is discharged to a waste ink absorber where it is subsequently stored for the duration of the service life of the ink jet printer.
Another consideration is the use of “full bleed” ink jet photographic quality printing. An overshoot of ink droplets from a print head can intentionally be made to fill the print sheet from edge-to-edge. The print sheet would not be adhered to a base sheet but would be independently fed through the ink jet printer. The overshoot of ink droplets in the “full bleed” process would be dispersed to a waste ink absorber where it is subsequently stored or transferred to a final waste ink reservoir for the duration of the service life of the ink jet printer.
In both cases, the collection of ink is not always uniform. Ink accumulates on the surface of the waste ink absorber device. It dries into a gel state that consequently clogs the waste ink absorber. The clogged waste ink absorber does not allow for efficient and uniform dispersal of waste ink into the body of the waste ink absorber. This results in an insufficient capacity for waste ink storage with respect to the life of the ink jet printer.
Nozzles can become contaminated or even clogged by contact with the waste ink. The print sheet can have unwanted ink spots on its non-printed backside. In either case, the quality of print is greatly reduced because of the accumulation of the ink in the waste ink absorber.
There is a need for a waste ink absorber that will eliminate waste ink clogging in the waste ink absorber and which will also allow for a sufficient amount of waste ink storage corresponding to the service life of an ink jet printer. The composite non-woven ink absorber, in accordance with the present invention, overcomes the limitations of the prior art. It is a substantial advance in the art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink jet absorber for use primarily in an ink jet printer.
Another object of the present invention is to provide a non-woven ink jet absorber.
A further object of the present invention is to provide a composite non-woven needlefelt for use as an ink jet absorber.
Yet a further object of the present invention is to provide an ink jet absorber that accomplishes the uniform and efficient absorption and transport of ink from a top surface of the composite non-woven material to the body of the composite non-woven material.
The ink jet absorber in accordance with the present invention utilizes a composite non-woven material, such as a composite non-woven needlefelt, having a low density/coarse denier top layer and at least one higher density/finer denier lower or bottom layer. The denier is understood to be the weight-per-unit-length of the fiber used to form the non-woven needlefelt. The ink jet absorber is intended primarily for use with ink jet printers, and will be discussed hereinafter in that context. It is to be understood that the ink jet absorber of the present invention is susceptible of other uses.
The ink jet absorber quickly absorbs waste ink discharged from ink jet nozzles and, through the inherent capillary gradient between layers in the composite non-woven material, disperses or transports the waste ink evenly from the surface of the top layer through to the bottom layer of the ink jet absorber. Typically, waste ink from ink jet nozzles is dropped onto the ink jet absorber at a specific point on the surface of the top layer. The ink jet absorber of the present invention will quickly disperse waste ink vertically through its top layer and will then subsequently disperse the waste ink evenly horizontally through the bottom layer of the ink jet absorber.
One important characteristic of the present invention is the provision of a capillary gradient between the top and bottom layers of the composite non-woven material. The capillary gradient is accomplished by constructing a composite non-woven material, such as a composite non-woven needlefelt, in the subject ink jet absorber, with a minimum of two layers having differing capillary forces between these layers. The capillary force of each layer is selected in accordance with the requirements of the specific application. The ink jet absorber of the present invention has a top layer consisting of a low density/coarse denier composition and at least a high density/fine denier composition bottom layer.
Capillary force in a non-woven material is a function of the surface tension of ink with respect to fiber type, contact angle of ink on the fiber and the fiber surface area per unit volume of the non-woven material, such as needlefelt. Capillary force in a non-woven material can be considered as being analogous to capillary head in a vertical capillary tube. The space between the fibers in the non-woven material can be approximated as a vertical capillary tube. The equation for force in a vertical capillary tube is given as follows:
F=2&pgr;r&sgr;
LV
cos &thgr;
LS
where,
F=Capillary Force
r=Tube Radius
&sgr;
LV
=Surface Tension
&thgr;
LS
=Contact Angle
The fiber surface area per unit volume of the non-woven material is a function of the non-woven material's density and fiber size. The equation for fiber surface area per unit volume of the non-woven material is given as follows:
SA
=
(
4
d
f
)
(
ρ
ρ
f
)
where,
SA=fiber surface area per unit volume
d
f
=diameter of fiber
&rgr;=density of non-woven needlefelt
&rgr;
f
=density of fiber
A higher SA or surface area will create many individual capillary tubes within the non-woven material, such as a needlefelt, thus creating a high capillary force, F, in the non-woven needlefelt. A low density/coarse denier layer will have a low fiber SA or surface area per unit volume of felt compared to a high density/fine denier layer. The ink jet absorber of the present invention has a top layer consisting of a low density/coarse denier composition and at least a bottom layer consisting of a high density/fine denier composition. The top layer can be considered as having a high permeability, or “open” structure, while the bottom layer can be considered as a having a low permeability with a high capillary force particularly in the horizontal direction. High permeability is understood to mean a low fiber surface area to unit volume structure and low permeability is understood to mean a high fiber surface area to unit volume structure.
The “open” structure of the top layer of the composite non-woven needlefelt or similar material ink absorber of the present invent
Lebold Alan
Sass Thomas
BMP America, Inc.
Jones Tullar & Cooper PC
Shewareged B.
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