Radiation imagery chemistry: process – composition – or product th – Electric or magnetic imagery – e.g. – xerography,... – Radiation-sensitive composition or product
Reexamination Certificate
2002-12-16
2004-08-24
RoDee, Christopher (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Electric or magnetic imagery, e.g., xerography,...
Radiation-sensitive composition or product
C430S970000, C430S059400, C430S059600, C430S064000, C430S065000, C430S133000, C430S058050
Reexamination Certificate
active
06780554
ABSTRACT:
BACKGROUND
This invention relates in general to layered imaging members comprised for example, of a photogenerating layer; (1) a first charge transport layer comprised for example, of a charge transport component and a resin binder, and thereover and in contact with the first layer; (2) a second top charge transport layer comprised for example, of a charge transport component, and a polymer of a styrene containing hindered phenol. Advantages associated with the imaging members of the present invention, in embodiments, thereof include for example, the avoidance of or minimal undesirable migration of a hindered phenol to the photogenerating layer to thereby avoid imaging member instability, such as, electrical performance degradation, and undesirable electrical characteristics especially on long term cycling of the member; coating of two transport layers in separate passes to for example, minimize the transport layers thickness variations which variations can cause image defects referred to as rain drops; minimizing and in embodiments, avoiding an increase in the lateral surface conductivity of the member which in turn can cause image degradation, referred to as lateral conductivity migration (LCM) and which disadvantages are minimized by adding to the second transport layer a polymer of styrene having attached thereto a hindered phenol moiety or moieties.
Processes of imaging, especially xerographic imaging and printing, including digital, are also encompassed by the present invention. More specifically, the layered photoconductive imaging members of the present invention can be selected for a number of different known imaging and printing processes including, for example, electrophotographic imaging processes, especially xerographic imaging and printing processes wherein charged latent images are rendered visible with toner compositions of an appropriate charge polarity. Moreover, the imaging members of this invention are useful in color xerographic applications, particularly high-speed color copying and printing processes and which members are in embodiments, sensitive in the wavelength region of, for example, from about 500 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source.
REFERENCES
Electrophotographic imaging members may be multilayered photoreceptors that comprise a substrate support, an electrically conductive layer, an optional charge blocking layer, an optional adhesive layer, a charge generating layer, a charge transport layer, and an optional protective or overcoating layers. The imaging members can be of several forms, including flexible belts, rigid drums, and the like. For a number of multilayered flexible photoreceptor belts, an anticurl layer may be employed on the backside of the substrate support, opposite to the side carrying the electrically active layers.
Various combinations of materials for the charge generating layers and charge transport layers have been disclosed. U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference, illustrates a layered photoreceptor having a separate charge generating layer (CGL) and a separate charge transport layer (CTL). The charge generating layer is capable of photogenerating holes and injecting the photogenerated holes into the charge transport layer. The photogenerating layer utilized in multilayered photoreceptors include, for example, inorganic photoconductive particles or organic photoconductive particles dispersed in a film forming polymeric binder. Examples of photosensitive members having at least two electrically operative layers including a charge generating layer and a diamine containing transport layer are disclosed in U.S. Pat. Nos. 4,265,990, 4,233,384, 4,306,008, 4,299,897 and 4,439,507, the disclosures of each of these patents being totally incorporated herein by reference in their entirety.
In multilayer photoreceptor devices, one property, for example, is the charge carrier mobility in the transport layer. Charge carrier mobility determines the velocities at which the photo-injected carriers transit the transport layer. For greater charge carrier mobility capabilities, for example, it may be necessary to increase the concentration of the active molecule transport compounds dissolved or molecularly dispersed in the binder. Phase separation or crystallization can establish an upper limit to the concentration of the transport molecules that can be dispersed in a binder. Thus there is desired an imaging member that exhibits excellent performance properties and minimizes lateral conductivity migration of the charge image pattern and which characteristics may be achievable by including in the member, especially the top charge transport layer a styrene polymer containing and attached thereto a hindered phenol and wherein the hindered phenol is present for example, in an amount of from about 2 weight percent to about 10 weight percent. In specific embodiments, the hindered phenol is present in an amount of from about 5 to about 8 percent by weight.
SUMMARY
Aspects of the present invention, relate to an electrophotographic imaging member comprising a photogenerating layer, (1) a first charge transport layer comprised of a charge transport component and a resin binder, and thereover and in contact with the first charge transport layer (2) a second top charge transport layer comprised of a charge transport component, a binder resin or polymer and a polymer of a styrene having attached thereto a hindered phenol, and wherein the migration of the hindered phenol to the first charge transport layer is avoided; methods of imaging as illustrated herein and imaging devices thereof.
The first charge transport layer includes at least one charge transport material, of for example, in embodiments, a charge, especially hole transport component and a polymer binder, and which layer can be deposited on a second charge transport layer containing a charge transport component, a resin binder and a polymer of a styrene containing a hindered phenol. In embodiments, the hindered phenol can be selected from the group consisting of octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, Thiodiethylene bis-(3,5-di-tert-butyl-4-hydroxy)hydrocinnamate, o,o-di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphonate, N,N′-hexamethylene bis-(3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione.
In embodiments the second top charge transport layer comprises a charge transport component and a polymer of styrene containing hindered phenol, where the polymer of styrene is represented by:
wherein x and y represent the number of segments.
In embodiments, the hindered phenol is present for example, in the styrene polymer in an amount of from about 0.05 to about 0.5 mole percent. In a more specific embodiment, the hindered phenol is present in the styrene polymer in an amount of from about 0.15 to about 0.3 mole percent. The hindered phenol is incorporated into the styrene polymer during esterification by a covalent bond connection. The resulting polymer in embodiments, has for example, a weight average molecular weight of from about 1,000 to 20,000, and a number average molecular weight of from about 1,500 to about 18,000. In a more specific embodiment, the resulting polymer has a weight average molecular weight of from about 3,500 to 15,000, and a number average molecular weight of from about 3,000 to about 10,000.
In specific embodiments, the hindered phenol comprises octadecyl-3,5-di-tert-butyl-4-hydroxyhydrociannamate, available as IRGANOX® from Ciba Specialty Chemicals.
For the application of each of the charge transport layers there can be selected a number of known suitable organic solvents such as, methylene chloride, toluene and tetrahydrofuran and wherein the total solid, that is charge transport and binder amount ratio to total solvent amount is for example, from about 10:90 weight percent to about 30:70 weight percent, and in embodime
Carmichael Kathleen M.
DeFeo Paul J.
Evans Kent J.
Fuller Timothy J.
Garland Karen S.
Oliff & Berridg,e PLC
Palazzoo Eugene
RoDee Christopher
Xerox Corporation
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