Patent Grant
8216661
1. Field of the Use
The present teachings relate generally to coating materials for electrophotographic devices and processes and, more particularly, to coating materials that contain nano-fibers for providing variable image gloss levels.
2. Background
Electrophotographic marking is performed by exposing a light image representation of a desired document onto a substantially uniformly charged photoreceptor. In response to that light image, the photoreceptor discharges to create an electrostatic latent image of the desired document on the photoreceptor's surface. Toner particles are then deposited onto that latent image to form a toner image. That toner image is then transferred from the photoreceptor onto a substrate such as a sheet of paper. The transferred toner image is then fused to the substrate, using heat and/or pressure. The surface of the photoreceptor is then cleaned of toner residue and recharged in preparation for production of another image.
Gloss is a property of a surface that relates to specular reflection. Specular reflection is a sharply defined light beam resulting from reflection off a smooth, uniform surface. Gloss follows the law of reflection which states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection. Gloss properties are generally measured in Gardner Gloss Units (ggu) by a gloss meter.
Gloss acceptability levels for copies and prints are dependent on the market segment involved. On color production prints, a particular level of image gloss is typically desired. The level of image gloss is significantly impacted by the toner formulation used in the printing process. Conventionally, the level of image gloss is further controlled by using additional equipment to adjust the image gloss after the fusing operation. It is desirable, however, to control the image gloss level without using additional equipment.
According to various embodiments, the present teachings include a fuser member. The fuser member can include a substrate and a coating material having an average surface roughness ranging from about 0.1 μm to about 1.5 μm disposed over the substrate. The coating material can include a polymer matrix and a plurality of nanoceram fibers disposed in the polymer matrix in a form selected from the group consisting of a non-agglomerated nano-fiber, a nano-fiber cluster, and a combination thereof.
According to various embodiments, the present teachings also include a fusing method. The fusing method can include first forming a contact arc between a coating material of a fuser roll and a backup member. The coating material can include a plurality of nanoceram fibers disposed in a polymer matrix, and the coating material can have an average surface roughness ranging from about 0.1 μm to about 1.5 μm. When fusing, a print medium can be passed through the contact arc such that toner images on the print medium contact the coating material and are fused on the print medium. The fused toner images on the print medium can have a gloss level ranging from about 30 ggu to about 70 ggu.
According to various embodiments, the present teachings further include a fusing system that includes a fuser roll and a backup roll. The fuser roll can include an outermost layer including a plurality of nanoceram fibers disposed in a polymer matrix in a form selected from the group consisting of a non-agglomerated nano-fiber, a nano-fiber cluster, and a combination thereof. The backup roll can be configured to form a contact arc with the fuser roll to fuse toner images on a print medium that passes through the contact arc. The outermost layer of the fuser roll can have an average surface roughness ranging from about 0.1 μm to about 1.5 μm such that the fused toner images have a gloss level ranging from about 30 ggu to about 70 ggu.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present teachings, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings.
It should be noted that some details of the figures have been simplified and are drawn to facilitate understanding of the embodiments rather than to maintain strict structural accuracy, detail, and scale.
Reference will now be made in detail to embodiments of the present teachings, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. In the following description, reference is made to the accompanying drawings that form a part thereof, and in which is shown by way of illustration specific exemplary embodiments in which the present teachings may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present teachings and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present teachings. The following description is, therefore, merely exemplary.
Exemplary embodiments provide coating materials useful for electrophotographic devices and processes. The coating materials can include a plurality of nanoceram fibers dispersed, distributed, and/or agglomerated in a polymer matrix. The coating materials can be used as an outermost layer for electrophotographic members and devices including, but not limited to, a fuser member or other fixing members, a pressure member, and/or a release donor member so as to control or improve, for example, fusing performances, printing performances, and/or thermal, mechanical and electrical properties of the electrophotographic members.
As used herein, unless otherwise specified, the term “nano-fiber” refers to an elongated structure, for example, a fibrous particulate, having at least one dimension, e.g., width or diameter, less than about 1000 nm and having an average aspect ratio ranging from about 10 to about 100, or from about 10 to about 50, or from about 10 to about 20. Generally, the aspect ratio is a ratio of a longest dimension to a shortest dimension of the nano-fiber, such as a ratio of the length to the diameter of the nano-fiber. The nano-fibers can have an average length ranging from about 20 nm to about 400 nm, or from about 20 nm to about 200 nm, or from about 20 nm to about 80 nm, and an average width or diameter ranging from about 2 nm to about 4 nm, or from about 2 nm to about 3 nm, or from about 2 nm to about 2.5 nm. In one embodiment, the nano-fibers can be about 2 nm in diameter and about 50 nm to about 1000 nm in length.
In embodiments, the nano-fibers can include various cross-sectional shapes including, but not limited to, a circular, square, rectangular, and/or triangular shape. The nano-fibers can have an average surface area, for example, ranging from about 450 m2/g to about 600 m2/g, or from about 450 m2/g to about 500 m2/g, or from about 450 m2/g to about 475 m2/g. In one embodiment, the nano-fibers can have an average surface area of about 600 m2/g.
As used herein, unless otherwise specified, the term “nanoceram fiber” refers to a nano-fiber that is primarily made of ceramic materials. Exemplary ceramic materials used for nanoceram fibers can include, but are not limited to, alumina, silica, zirconia, titania, silicon carbide, silicon nitride, tungsten carbide, or other ceramics. In one embodiment, the nanoceram fibers can be alumina ceramic fibers. In embodiments, the ceramic nano-fibers can include, for example, a calcined ceramic, a tabular ceramic, a fused ceramic, and/or a fumed ceramic. As disclosed herein, the nanoceram fibers dispersed in a polymer matrix can be of only one type or a mixture of two or more ceramic types selected from the above described ceramics, which can be used in the same or different, amounts and fiber sizes, in the polymer matrix.
In embodiments, a plurality of nano-fibers can be disposed in a polymer matrix as non-agglomerated nano-fibers (see 120 of
Specifically,
The non-agglomerated nano-fibers 120 and/or nano-fiber clusters 125 can be distributed within the polymer matrix 110 to substantially control or enhance physical properties, such as, for example, thermal conductivity, and/or mechanical robustness of the resulting polymer matrix, as well as fusing performances, and/or printing performances. For example, the coating material can be used as an outermost layer of a fuser member in a variety of fusing subsystems and embodiments, wherein the coating materials can provide improved gloss performance of the fused images depending on the polymers involved in the polymer matrix.
Various polymers can be used for the polymer matrix 110 to provide desired properties according to specific applications. The polymers used for the polymer matrix 110 can include, but are not limited to, silicone elastomers, fluoroelastomers, fluoroplastics, thermoelastomers, fluororesins, and/or resins.
In one embodiment, the polymer matrix 110 can include fluoroelastomers, e.g., having a monomeric repeat unit selected from the group consisting of tetrafluoroethylene (TFE), perfluoro(methyl vinyl ether), perfluoro(propyl vinyl ether), perfluoro(ethyl vinyl ether), vinylidene fluoride (VDF or VF2), hexafluoropropylene (HFP), and a mixture thereof. The fluoroelastomers can also include a curing site monomer.
Commercially available fluoroelastomers can include, for example, VITON® A: copolymers of hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2); VITON® B: terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP); VITON® GF: tetrapolymers of TFE, VF2, HFP); as well as VITON® E; VITON® E-60C; VITON® E430; VITON® 910; VITON® GH; and VITON® GF. The VITON® designations are Trademarks of E.I. DuPont de Nemours, Inc. (Wilmington, Del.) and are also referred herein as “VITON.”
Other commercially available fluoroelastomers can include those available from 3M Corporation (St. Paul, Minn.) including, for example, DYNEON™ fluoroelastomers, AFLAS® fluoroelastomers (e.g., a poly(propyiene-tetrafluoroethylene)), and FLUOREL® fluoroelastomers (e.g. FLUOREL®II (e.g., LII900) a poly(propylene-tetrafluoroethylenevinylidenefluoride), FLUOREL® 2170, FLUOREL® 2174, FLUOREL® 2176, FLUOREL® 2177, and/or FLUOREL® LVS 76. Additional commercially available fluoroelastomer materials can include the “tecnoflons” identified as FOR®-60KIR, FOR®-LHF, FOR®-NM, FOR®-THF, FOR®-TFS, FOR®-TH, and FOR®-TN505, available from Solvay Solexis (West Deptford, N.J.).
In embodiments, the polymer matrix 110 can include polymers cross-linked with an effected curing agent (also referred to herein as cross-linking agent, or cross-linker) to form elastomers that are relatively soft and display elastic properties. For example, when the polymer matrix uses a vinylidene-fluoride-containing fluoroelastomer, the curing agent can include, a bisphenol compound, a diamino compound, an aminophenol compound, an amino-siloxane compound, an amino-silane, and/or a phenol-silane compound. An exemplary bisphenol cross-linker can be VITON® Curative No. 50 (VC-50) available from E. I. du Pont de Nemours, Inc. VC-50 can be soluble in a solvent suspension and can be readily available at the reactive sites for cross-linking with, for example, VITON®-GF (E. I. du Pont de Nemours, Inc.).
The polymer matrix 110 can include fluoroplastics including, but not limited to, PFA (polyfluoroalkoxypolytetrafluoroethylene), PTFE (polytetrafluoroethylene), and/or FEP (fluorinated ethylenepropylene copolymer). These fluoroplastics can be commercially available from various designations, such as TEFLON® PFA, TEFLON® PTFE, or TEFLON® FEP available from E.I. DuPont de Nemours, Inc. (Wilmington, Del.).
In
In embodiments, various other particle fillers including conventional particle fillers can be optionally included in the disclosed coating materials. As exemplarily shown in
The particle fillers 130 can have dimensions on the micron and/or nano-scales. The particle fillers 130 can be organic, inorganic, or metallic and can include conventional composite filler materials of, for example, metals or metal oxides including copper particles, copper flakes, copper needles, aluminum oxide, nano-alumina, titanium oxide, silver flakes, aluminum nitride, nickel particles, silicon carbide, silicon nitride, etc.
In embodiments, the plurality of nano-fibers in one or more forms of the non-agglomerated nano-fibers 120 (e.g., nanoceram fibers), and the nano-fiber clusters 125 (e.g., nanoceram fiber clusters) shown in
For example, when the forms of the non-agglomerated nano-fibers 120 (e.g., nanoceram fibers) and the nano-fiber clusters 125 (e.g., nanoceram fiber clusters) are both present in the polymer matrix 110 as shown in
In embodiments, the coating materials 100A-F can provide desirable average surface roughness, for example, ranging from about 0.01 μm to about 3.0 μm, or from about 0.1 μm to about 1.5 μm, or from about 0.5 μm to about 1.0 μm. For example, this surface roughness can facilitate controlling of image gloss levels when the coating materials are used as fuser member materials during electrophotographic printing.
The coating materials 100A-F can provide desirable mechanical properties. For example, the coating materials 100A-F can have a tensile strength ranging from about 500 psi to about 5,000 psi, or from about 1,000 psi to about 4,000 psi, or from about 1,500 psi to about 3,500 psi; an elongation % ranging from about 20% to about 1000%, or from about 50% to about 500%, or from about 100% to about 400%; a toughness ranging from about 500 in.-lbs./in.3 to about 10,000 in.-lbs./in.3, or from about 1,000 in.-lbs./in.3 to about 5,000 or from about 2,000 in.-lbs./in.3 to about 4,000 in.-lbs./in.3; and an initial modulus ranging from about 100 psi to about 2,000 psi, or from about 500 psi to about 1,500 psi, or from about 800 psi to about 1,000 psi.
The coating materials 100A-F can provide a desirable average thermal diffusivity ranging from about 0.01 mm2/s to about 0.5 mm2/s, or from about 0.05 mm2/s to about 0.25 mm2/s, or from about 0.1 mm2/s to about 0.15 mm2/s, and a desirable average thermal conductivity ranging from about 0.01 W/mK to about 1.0 W/mK, or from about 0.1 W/mK to about 0.75 W/mK, or from about 0.25 W/mK to about 0.5 W/mK.
In various embodiments, the disclosed coating materials 100A-F can be used in any suitable electrophotographic members and devices. For example,
As shown in
The substrate 205 can be made of a material including, but not limited to, a metal, a plastic, and/or a ceramic. For example, the metal can include aluminum, anodized aluminum, steel, nickel, and/or copper. The plastic can include polyimide, polyester, polyetheretherketone (PEEK), poly(arylene ether), and/or polyamide.
As illustrated, the member 200 can be, for example, a fuser roller including the outermost layer 255 formed over an exemplary core substrate 205. The core substrate can take the form of, e.g., a cylindrical tube or a solid cylindrical shaft, although one of the ordinary skill in the art would understand that other substrate forms, e.g., a belt substrate, can be used to maintain rigidity and structural integrity of the member 200.
The outermost layer 255 can include, for example, the coating material 100A-100F as shown in
For example, the member 200B can have a 2-layer configuration having a compliant/resilient layer 235, such as a silicone rubber layer, disposed between the outermost layer 255 and the core substrate 205. In another example, the exemplary fuser member 200 can include an adhesive layer (not shown), for example, formed between the resilient layer 235 and the substrate 205 or between the resilient layer 235 and the outermost layer 255.
In one embodiment, the exemplary fuser member 200A-B can be used in a conventional fusing system to improve fusing performances as disclosed herein.
The exemplary system 300 can include the exemplary fuser roll 200A or 200B having an outermost layer 255 over a suitable substrate 205. The substrate 205 can be, for example, a hollow cylinder fabricated from any suitable metal. The fuser roll 200 can further have a suitable heating element 306 disposed in the hollow portion of the substrate 205 which is coextensive with the cylinder. Backup or pressure roll 308, as known to one of ordinary skill in the art, can cooperate with the fuser roll 200 to form a nip or contact arc 310 through which a print medium 312 such as a copy paper or other print substrate passes, such that toner images 314 on the print medium 312 contact the outermost layer 255 during the fusing process. The fusing process can be performed at a temperature ranging from about 60° C. (140° F.) to about 300° C. (572° F.), or from about 93° C. (200° F.) to about 232° C. (450° F.), or from about 160° C. (320° F.) to about 232° C. (450° F.). Optionally, a pressure can be applied during the fusing process by the backup or pressure roll 308. Following the fusing process, after the print medium 312 passing through the contact arc 310, fused toner images 316 can be formed on the print medium 312.
As disclosed herein, the gloss output of the fused toner images 316 on the print medium 310 can be controlled by using the nano-fiber-containing coating materials as the outermost layer of the fuser member. Depending on the polymers selected for the polymer matrix or the nano-fibers, suitable levels of image gloss can be obtained as desired. For example, conventional fuser materials produce images with a gloss level greater than 70 ggu in iGen configurations, while the exemplary fuser materials including nano-fibers can produce images with controllable, e.g., reduced, gloss level of the fused or printed images of less than about 70 ggu, for example, in a range from about 30 ggu to about 70 ggu, or from about 40 ggu to about 60 ggu, or from about 45 ggu to about 55 ggu.
In addition to controlling the gloss level of fused images, the disclosed coating materials can also provide desired physical properties for the fuser members. In an exemplary embodiment, a coating material having about 15% nanoceram fibers by weight in a VITON® GF polymer matrix can have a thermal conductivity of about 0.28 Wm−1K−1, while conventional fuser rolls without using the nano-fibers exhibit a thermal conductivity of less than about 0.17 Wm−1K−1. The improved thermal conductivities can provide fast ramp up times during fusing.
Various embodiments can also include methods for forming the disclosed coating materials (see
At 410 in
For example, the liquid coating dispersion can be formed by first dissolving the polymer in a suitable solvent, followed by adding a plurality of nano-fibers into the solvent in an amount to provide desired properties, such as a desired fusing properties, thermal conductivities, or mechanical robustness. In another example, the liquid coating dispersion can be formed by first mixing the polymer and a plurality of nano-fibers, followed by dissolving or dispersing the mixture in an appropriate solvent as described above.
In various embodiments, when preparing the liquid coating dispersion, a mechanical aid, such as an agitation, sonication and/or attritor ball milling/grinding, can be used to facilitate the mixing of the dispersion. For example, an agitation set-up fitted with a stir rod and Teflon blade can be used to thoroughly mix the nano-fibers with the polymer in the solvent, after which additional chemical curatives, such as curing agent, and optionally other particle fillers such as metal oxides, can be added into the mixed dispersion.
At 420, an exemplary fuser member can be formed by applying an amount of the liquid coating dispersion to a substrate, such as the substrate 205 in
At 430, the applied liquid coating dispersion can then be solidified, e.g., by a curing process, to form a coating layer, e.g., the layer 255, on the substrate, e.g., the substrate 205 of
In embodiments, the solidified coating layer, i.e., the outermost layer of the fuser member can have a thickness ranging from 5 μm to about 100 μm, or from about 10 μm to about 75 μm, or from about 15 μm to about 50 μm. In embodiments, additional functional layer(s) (see 235 of
The outermost layer of the exemplary fuser member was formed to have a concentration of about 15% by weight of nanoceram fibers in a VITON® GF topcoat fuser material, which was coated on a conventional iGen fuser roll.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein.
While the present teachings have been illustrated with respect to one or more implementations, alterations and/or modifications can be made to the illustrated examples without departing from the spirit and scope of the appended claims. In addition, while a particular feature of the present teachings may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular function. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description and the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.”
Further, in the discussion and claims herein, the term “about” indicates that the value listed may be somewhat altered, as long as the alteration does not result in nonconformance of the process or structure to the illustrated embodiment. Finally, “exemplary” indicates the description is used as an example, rather than implying that it is an ideal.
Other embodiments of the present teachings will be apparent to those skilled in the art from consideration of the specification and practice of the present teachings disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the present teachings being indicated by the following claims.
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