Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Post imaging process – finishing – or perfecting composition...
Reexamination Certificate
2000-02-10
2001-02-13
Martin, Roland (Department: 1753)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Post imaging process, finishing, or perfecting composition...
Reexamination Certificate
active
06187498
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is generally directed to liquid toner and developer compositions and to imaging processes thereof. More specifically, the present invention relates to improved liquid developer compositions and improved development and imaging processes thereof arising from, for example, including an adhesion promoting compound in the liquid developer.
A significant problem associated with prior art liquid developers, particularly liquid developers that are subsequently laminated is delamination or poor adhesion of the laminate or overcoat to the ink image and to the substrate. The problem is particularly pronounced for laminated images which experience high or variable humidity, and related extreme environmental and temperature fluctuations. Total or partial delamination typically results in deterioration or destruction of the image quality thereby rendering the image incomprehensible and unacceptable from an aesthetic appeal perspective. The foregoing delamination and image degradation problems are particularly acute where the laminate overcoat layer employs a vinyl acrylic adhesive. These and other lamination and image defect problems are solved in embodiments of the present invention.
PRIOR ART
In U.S. Pat. No. 5,842,097, issued Nov. 24, 1998, to Kanbayashi, et al., there is disclosed an image forming method, including the steps of: forming a toner image with a toner having toner particles and an external additive on a surface of a first image-carrying member which includes a support and a lamination layer disposed thereon containing a peeling layer, fixing the toner image on the surface of the peeling layer of the first image-carrying member to form a fixed image, peeling the peeling layer having the fixed image from the first image-carrying member, and transferring the fixed image on the peeling layer onto a second image-carrying member while swelling the peeling layer, wherein the lamination layer has at least the peeling layer and an adhesive layer, the peeling layer at least including a transfer layer and having an area expansion ratio of 102-106%. The transfer layer may preferably be a composition containing a high-saponified polyvinyl alcohol having a saponification degree of at least 90% and a low-saponified polyvinyl alcohol having a saponification degree of below 90%. The binder resin may preferably be polyester resin having an acid value of 2-25 mg KOH/g. The peeling layer having an appropriate area expansion ratio (102-106%, preferably 102-105%) is effective in allowing quick and uniform peeling thereof from the fixed image.
In U.S. Pat. No. 5,725,935, issued Mar. 10, 1998, to Rajan, there is disclosed signage articles having a layer of fused dry toner powder which is fused by employing a tacky pressure-sensitive adhesive and low compression. Suitable tacky pressure-sensitive adhesives include alkyl acrylate polymers or copolymers, alkyl vinyl ether polymers or copolymers, polyisobutylene, polybutadiene, and butadiene-styrene copolymers. Such signage articles further comprise a transparent cover layer disposed over the fused dry toner powder-bearing surface. Also disclosed are methods of forming signage articles, one method comprising the steps of applying dry toner powder to a first substrate surface, applying a composition including a tacky pressure-sensitive adhesive to a second substrate surface, and laminating the two substrates to admix the dry toner powder and the tacky pressure-sensitive adhesive. Either the first or second substrate may be the transparent cover layer of the resulting signage article.
In U.S. Pat. No. 5,655,192, issued Aug. 5, 1997, to Denton et al., there is disclosed a method and apparatus for compaction of a liquid ink developed image in a liquid ink type multicolor electrostatographic printing machine of the type utilizing liquid developing material, particularly an image-on-image type liquid ink multicolor system. The image compacting apparatus includes a biased electrode situated proximate to the image on an image bearing surface, and a liquid applicator for depositing liquid insulating material in a conditioning gap defined by the electrode and the image bearing surface. A high electric potential is applied to the electrode for generating a large electric field in the gap to electrostatically compress toner particles into image areas on the image-bearing surface. The liquid insulating material is deposited into the conditioning gap for avoiding the risk of air breakdown as may occur in an electrostatic device of this nature due to the small geometry of the apparatus and the tendency of air ionization in an air gap between electrically biased surfaces. Preferably, the liquid insulating material is the very same material utilized as the liquid carrier component of the liquid developing material.
Liquid developer and related compositions and processes for their preparation are known, reference for example, U.S. Pat. Nos. 5,563,015, 5,565,299, 5,567,564, 5,382,492, 5,714,993, 5,570,173, and 5,612,777. The disclosures of the aforementioned patents are incorporated herein by reference in their entirety.
There remains a need for liquid electrostatic toner and developer compositions and processes thereof which provide high quality and high resolution developed images over the entire range of known development and printing speeds, and for highly robust and environmentally stable laminated images prepared from the developed images.
The developers and development processes thereof of the present invention are useful in many applications, including toners for use in electrophotographic imaging processes, such as digital printing and copying systems including color systems, and for use for example, in liquid marking, such as liquid electrostatic printing, ink jet printing applications, and offset printing inks and applications.
SUMMARY OF THE INVENTION
Embodiments of the present invention, include:
A process comprising:
forming a first image on a first substrate with a liquid toner comprising a resin, a colorant, a carrier liquid, and an adhesion promoting compound;
transferring the image from the first substrate to a second substrate;
overcoating the image on the second substrate with a transparent overcoat layer, and
treating the resulting overcoated image;
A liquid toner comprising: a first resin, a second adhesion promoting resin, a colorant, and a carrier liquid; and
A printing machine comprising:
a liquid developer image forming device adapted for forming images on a first substrate;
a second substrate adapted for receiving the image from the first substrate;
a coater adapted for overcoating the resulting image on the second substrate; and
a heater adapted to thermally activate an adhesion promoting compound contained in the liquid developer thereby substantially permanently affixing the image or images and overcoat to the second substrate.
These and other embodiments of the present invention are illustrated herein.
DETAILED DESCRIPTION OF THE INVENTION
The developers and development processes of the present invention provide a simple and effective solution to the problem of delamination or poor lamination stability encountered, for example, in liquid ink development printing systems which employ conventional liquid electrostatic toner or ink developer formulations.
Although not wanting to be limited by theory it is believed that the vinyl acrylic adhesive component or other formulation ingredients of the laminate may exacerbate the delamination and image distortion problems by, for example, plasticizing the toner image layer(s) and thereby vitiate adhesive and cohesive attractive forces associated with the toner resin and which forces act on the substrate, the laminate overcoat, and any adjacent toner layers, for example, images provided by “image-on-image” type development processes.
Thus the present invention in embodiments provides a process comprising:
forming a first image on a first substrate with a liquid toner comprising a resin, a colorant, a carrier liquid, and an adhesion promoting compound;
Gibson George A.
Knapp Christopher M.
Pan David H.
Spiewak John W.
Haack John L.
Martin Roland
Xerox Corporation
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