Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2001-03-23
2002-12-10
Rodee, Christopher (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S078000, C430S133000, C430S134000, C430S135000
Reexamination Certificate
active
06492080
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is generally directed to photoresponsive devices, and imaging apparatus and processes thereof. More specifically, the present invention relates to improved photoresponsive devices comprised generally of a photogenerating layer and a transport layer. The present invention provides a process for selecting or fine tuning the sensitivity of photoresponsive devices by preparing and including in the photogenerator layer of the device a mixture of chlorogallium phthalocyanine (ClGaPc) photopigment particles, and which mixture of ClGaPc photopigment particles are the same polymorph but have a different origin or source, and the different source materials possess a different sensitivity.
The photoresponsive devices of the present invention are useful as imaging members in various electrostatographic imaging systems, including those systems wherein electrostatic latent images are formed on the imaging member. Additionally, the photoresponsive devices of the present invention can be irradiated with light, for example, as generated by a known laser, to accomplish, for example, latent image formation by, for example, charged area discharge (CAD) or dark area discharge (DAD) methodologies.
Numerous photoresponsive devices for electrostatographic imaging systems are known including selenium, selenium alloys, such as arsenic selenium alloys; layered inorganic photoresponsive, and layered organic devices. Examples of layered organic photoresponsive devices include those containing a charge transporting layer and a charge generating layer, or alternatively a photogenerator layer. Thus, for example, an illustrative layered organic photoresponsive device can be comprised of a conductive substrate, overcoated with a charge generator layer, which in turn is overcoated with a charge transport layer, and an optional overcoat layer overcoated on the charge transport layer. In a further “inverted” variation of this device, the charge transporter layer can be overcoated with the photogenerator layer or charge generator layer. Examples of generator layers that can be employed in these devices include, for example, charge generator materials such as pigments, selenium, cadmium sulfide, vanadyl phthalocyanine, x-metal free phthalocyanines, dispersed in binder resin, while examples of transport layers include dispersions of various diamines, reference for example, U.S. Pat. No. 4,265,990, the disclosure of which is incorporated herein by reference in its entirety.
There continues to be a need for improved photoresponsive devices, and improved imaging systems utilizing such devices. Additionally, there continues to be a need for photoresponsive devices of varying sensitivity, which devices are economical to prepare and retain their properties over extended periods of time. Furthermore there continues to be a need for photoresponsive devices that permit both normal and reverse copying of black and white as well as full color images, especially in high speed digital printing systems.
PRIOR ART
In U.S. Pat. No. 5,588,991, issued Dec. 31, 1996, and U.S. Pat. No. 5,688,619, issued Nov. 18, 1997, both to Hongo, et al., there is disclosed a process for producing a chlorogallium phthalocyanine crystal comprising mechanically dry-grinding chlorogallium phthalocyanine and subjecting the crystal [to] conversion, the weight ratio of chlorogallium phthalocyanine to the grinding media is set at a range of from ⅕ to {fraction (1/1,000)}. The resulting chlorogallium phthalocyanine crystal excels in the dispersability in a binding resin and the stability in the dispersion.
In U.S. Pat. No. 5,521,306, issued May 28, 1996, to Burt, et al., there is disclosed a process for the preparation of Type V hydroxygallium phthalocyanine which comprises the in situ formation of an alkoxy-bridged gallium phthalocyanine dimer, hydrolyzing said alkoxy-bridged gallium phthalocyanine dimer to hydroxygallium phthalocyanine, and subsequently converting the hydroxygallium phthalocyanine product obtained to Type V hydroxygallium phthalocyanine.
In U.S. Pat. No. 5,472,816, Dec. 5, 1995, to Nukada et al., there is disclosed a halogen-containing hydroxygallium phthalocyanine crystal showing intense diffraction peaks at Bragg angles (2 . . . theta . . . degree . . . +−.0.2.degree) of (1) 7.7, 16.5, 25.1 and 26.6 degrees; (2) 7.9, 16.5, 24.4, and 27.6 degrees; (3) 7.0, 7.5, 10.5, 11.7, 12.7, 17.3, 18.1, 24.5, 26.2, and 27.1 degrees; (4) 7.5, 9.9, 12.5, 16.3, 18.6, 25.1, and 28.3 degrees; or (5) 6.8, 12.8, 15.8, and 26.0 degrees, and an electrophotographic photoreceptor containing the halogen-containing hydroxygallium phthalocyanine crystal as a charge generating material are disclosed. Hydroxygallium phthalocyanine crystals are produced by reacting a gallium trihalide with phthalonitrile or diiminoisoindoline in a halogenated aromatic hydrocarbon solvent, treating the resulting halogenated gallium phthalocyanine with an amide solvent, and hydrolyzing the halogenated gallium phthalocyanine. The photoreceptor exhibits stabilized electrophotographic characteristics.
Also of interest are U.S. Pat. Nos. 5,493,016, 5,456,998, and 5,466,796. The aforementioned references are incorporated in their entirety by reference herein.
The disclosures of each the above mentioned patents are incorporated herein by reference in their entirety. The appropriate components and processes of these patents may be selected for the materials and processes of the present invention in embodiments thereof.
In the devices, imaging apparatuses, and processes of the prior art, various significant problems exist. For example, in the manufacture of photogenerator compounds for the xerographic arts, it is common practice to reproduce a photopigment synthetic procedure as exactly as possible each and every time the process is used in order to manufacture a very consistent target photogenerator compound material and thereby provide the exact photosensitivity demanded by the specifications of a particular printer or copier model. It is known that the synthesis conditions employed, including the solvent used, among other factors, play an irreversible role in imparting to the photogenerator compound so formed certain indelible electrical characteristics which can only moderately be manipulated by subsequent processing steps. The particular printer or copier has electronics and mechanical subsystems which are developed along with the photoreceptor imaging member to achieve a desired image quality. The photoreceptor fabrication conditions, including the particular plant or plants in which manufacturing takes place, can give rise to variations in the photoreceptor's performance in the printer and copier products. Image quality problems can also arise for particular models in field use which may then require changes in photoreceptor photogenerator specifications, or a need to adjust the sensitivity of the photoreceptor, up or down, as required by a particular application, a machine, a developer design change, or a customer requirement. As a consequence of the above described variables, it is advantageous to be able to manufacture photogenerators, and thereby photoreceptors, with variations as required during the lifetime of a given printer or copier design program which allows for minimal variation in the photoreceptor manufacturing conditions. These and other advantages are enabled with the articles, apparatuses, and processes of the present invention.
SUMMARY OF THE INVENTION
Embodiments of the present invention, include:
A process comprising:
forming a first chlorogallium phthalocyanine (ClGaPc) in N-methyl-2-pyrrolidone (NMP) to form a ClGaPc (NMP) Type-I product;
forming a second chlorogallium phthalocyanine in dimethyl sulfoxide (DMSO) to form a ClGaPc (DMSO) Type-I product;
separately dry milling and then wet treating the resulting Type-I products to convert them to a more sensitive Type-II polymorph;
blending the resulting Type-II products together along with a resin and a solvent for the resin to form a
Burt Richard A.
Hor Ah-Mee
Hsiao Cheng-Kuo
Liebermann George
Rodee Christopher
Thompson Robert
Xerox Corporation
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