Patent Application
20080069609
For a better understanding, reference may be had to the accompanying figures.
The disclosure herein relates to fuser members having a substrate, conformable intermediate layer, and outer fluoropolymer filled fluoroelastomer configuration. The addition of the fluoropolymer additive to the fluoroelastomer outer coating, in embodiments, improves topcoat wear properties, improves toner release, diminishes or eliminates problems of adhesion to the silicone layer, and allows for lower curing temperatures when used with a conformable silicone rubber intermediate layer.
Referring to
After the toner particles have been deposited on the photoconductive surface, in image configuration, they are transferred to a copy sheet 16 by transfer means 15, which can be pressure transfer or electrostatic transfer. Alternatively, the developed image can be transferred to an intermediate transfer member and subsequently transferred to a copy sheet.
After the transfer of the developed image is completed, copy sheet 16 advances to fusing station 19, depicted in
In
Backup or pressure roll 6 cooperates with fuser roll 5 to form a nip or contact arc 9 through which a copy paper or other substrate 16 passes such that toner images 21 thereon contact fluoroelastomer surface 2 of fuser roll 5. As shown in
In the embodiment shown in
In embodiments, there may be present an outer release layer 27 positioned on the outer layer 2 as shown in
Examples of the outer surface of the fuser system members include fluoroelastomers. Specifically, suitable fluoroelastomers are those described in detail in U.S. Pat. Nos. 5,166,031, 5,281,506, 5,366,772 and 5,370,931, together with U.S. Pat. Nos. 4,257,699, 5,017,432 and 5,061,965, the disclosures each of which are incorporated by reference herein in their entirety. As described therein, these elastomers are from the class of 1) copolymers of two of vinylidenefluoride, hexafluoropropylene, and tetrafluoroethylene; 2) terpolymers of vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene; and 3) tetrapolymers of vinylidenefluoride, hexafluoropropylene, tetrafluoroethylene and cure site monomer. These fluoroelastomer are known commercially under various designations such as VITON A®, VITON B®, VITON E®, VITON E 60C®, VITON E430®, VITON 910®, VITON GH®; VITON GF®; VITON ETP®. The VITON® designation is a Trademark of E.I. DuPont de Nemours, Inc. The cure site monomer can be 4-bromoperfluorobutene-1,1,1-dihydro-4-bromoperfluorobutene-1,3-bromoperfluoropropene-1,1,1-dihydro-3-bromoperfluoropropene-1, or any other suitable, known cure site monomer commercially available from DuPont. Other commercially available fluoropolymers include FLUOREL 2170®, FLUOREL 2174®, FLUOREL 2176®, FLUOREL 2177® and FLUOREL LVS 76®, FLUOREL® being a Trademark of 3M Company. Additional commercially available materials include AFLAS™ a poly(propylene-tetrafluoroethylene) and FLUOREL II® (LII900) a poly(propylene-tetrafluoroethylenevinylidenefluoride) both also available from 3M Company, as well as the Tecnoflons identified as FOR-60KIR®, FOR-LHF®, NM® FOR-THF®, FOR-TFS®, TH®, and TN505®, available from Montedison Specialty Chemical Company.
Examples of three known fluoroelastomers are (1) a class of copolymers of two of vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene, such as those known commercially as VITON A® (2) a class of terpolymers of vinylidenefluoride, hexafluoropropylene and tetrafluoroethylene known commercially as VITON B® and (3) a class of tetrapolymers of vinylidenefluoride, hexafluoropropylene, tetrafluoroethylene and cure site monomer known commercially as VITON GH® or VITON GF®.
The fluoroelastomers VITON GH® and VITON GF® have relatively low amounts of vinylidenefluoride. The VITON GF® and Viton GH® have about 35 weight percent of vinylidenefluoride, about 34 weight percent of hexafluoropropylene, and about 29 weight percent of tetrafluoroethylene with about 2 weight percent cure site monomer.
The amount of fluoroelastomer compound in solution in the outer layer solutions, in weight percent of total solids, is from about 10 to about 25 percent, or from about 16 to about 22 percent by weight of total solids. Total solids as used herein include the amount of fluoroelastomer, optional adjuvants and fillers, other solid materials, and includes the fluoropolymer filler.
In addition to the fluoroelastomer, the outer layer may comprise a fluoropolymer or other fluoroelastomer blended with the above fluoroelastomer. Examples of suitable polymer blends include the above fluoroelastomer blended with a fluoropolymer selected from the group consisting of polytetrafluoroethylene and perfluoroalkoxy. The fluoroelastomer can also be blended with non-fluorinated ethylene or non-fluorinated propylene.
The substrate, intermediate layer, and/or outer layer, in embodiments, may comprise fillers dispersed therein. These fillers can have the ability to increase the material hardness or modulus into the desired range.
A filler is included in the outer fluoroelastomer layer. The filler is a fluoropolymer. Examples of suitable fluoropolymer fillers include TEFLON®-like fillers such as polytetrafluoroethylene (PTFE) powder, perfluoroalkoxy (PFA) materials, fluorinated ethylenepropylene copolymer (FEP), polyfluoroalkoxy polytetrafluoroethylene (PFA TEFLON®), ethylene chlorotrifluoro ethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene perfluoromethylvinylether copolymer (MFA), and the like, and mixtures thereof. Specific commercially available fluoropolymer fillers include those sold under the names DYNEON® THV 200A; ZONYL® MP 1000; and the like. The fluoropolymer filler is present in the outer fluoroelastomer layer in an amount of from about 10 to about 50 percent, or from about 20 to about 40 percent, or from about 30 to about 35 percent by weight of total solids.
A filler can be included in the intermediate layer, and a second filler can be included along with the fluoropolymer filler, in the outer layer. Examples of suitable fillers for inclusion in the intermediate layer, and for inclusion in the outer layer (in addition to the fluoropolymer filler) include fillers such as metals, metal oxides, doped metal oxides, carbon blacks, ceramics, polymers, and the like, and mixtures thereof. Examples of suitable metal oxide fillers include titanium dioxide, tin (II) oxide, aluminum oxide, indium-tin oxide, magnesium oxide, copper oxide, iron oxide, silica or silicon oxide, and the like, and mixtures thereof. Examples of carbon fillers include carbon black (such as N-990 thermal black, N330 and N110 carbon blacks, and the like), graphite, fluorinated carbon (such as ACCUFLUOR® or CARBOFLUOR®), and the like, and mixtures thereof. Examples of ceramic materials include aluminum nitrate, boron nitride, silicates such as zirconium silicates, and the like, and mixtures thereof. Examples of polymer fillers include polytetrafluoroethylene powder, polypyrrole, polyacrylonitrile (for example, pyrolyzed polyacrylonitrile), polyaniline, polythiophenes, and the like, and mixtures thereof. The optional filler is present in the intermediate layer, and/or outer layer in an amount of from about 0 to about 30 percent, or from about 1 to about 20 percent, or from about 1 to about 5 percent by weight of total solids in the layer.
The thickness of the outer fluoroelastomer surface layer of the fuser member herein is from about 10 to about 250 micrometers, or from about 15 to about 100 micrometers.
The intermediate silicone rubber layer is conformable, in embodiments. The intermediate layer may be present between the substrate and the outer fluoroelastomer surface. Examples of suitable intermediate layers include silicone rubbers such as room temperature vulcanization (RTV) silicone rubbers; high temperature vulcanization (HTV) silicone rubbers and low temperature vulcanization (LTV) silicone rubbers. These rubbers are known and readily available commercially such as SILASTIC® 735 black RTV and SILASTIC® 732 RTV, both from Dow Corning; and 106 RTV Silicone Rubber and 90 RTV Silicone Rubber, both from General Electric. Other suitable silicone materials include the siloxanes (such as polydimethylsiloxanes); fluorosilicones such as Silicone Rubber 552, available from Sampson Coatings, Richmond, Va.; liquid silicone rubbers such as vinyl crosslinked heat curable rubbers or silanol room temperature crosslinked materials; and the like. Another specific example is Dow Corning Sylgard 182. The intermediate layer has a thickness of from about 0.5 to about 20 mm, or from about 1 to about 5 mm. The intermediate layer is conformable and has a durometer of from about 53 to about 85 or from about 64 to about 80 Shore A.
There may be provided an adhesive layer between the substrate and the intermediate layer. There may also be an adhesive layer between the intermediate layer and the outer layer. In the absence of an intermediate layer, the fluoroelastomer layer may be bonded to the substrate via an adhesive layer.
Generally, the fuser member can be produced by priming a metal core (in embodiments, the core may comprise aluminum). The primer is used to promote adhesion of the intermediate layer. A silicone rubber intermediate layer is applied to the top in any known and suitable manner, such as injection or compression molding, or the like. The outer fluoroelastomer layer is then applied to the silicone rubber layer by any suitable means, such as by flowcoating, or the like. The fluoropolymer fillers are directly added to the fluoroelastomer during the mixing process.
Release agents or fusing oils can be provided onto the outer layer of the fuser member via a delivery mechanism such as a delivery roll. The delivery roll is partially immersed in a sump, which houses the fuser oil or release agent. The oil is renewable in that the release oil is housed in a holding sump and provided to the fuser roll when needed, optionally by way of a release agent donor roll in an amount of from about 0.1 to about 20 mg/copy, or from about 1 to about 12 mg/copy. The system by which fuser oil is provided to the fuser roll via a holding sump and optional donor roll is well known. The release oil may be present on the fuser member in a continuous or semicontinuous phase. The fuser oil in the form of a film is in a continuous phase and continuously covers the fuser member.
Examples of suitable fuser oils include amino functional fuser oils, mercapto functional fuser oils, fluorosilicone fuser oils, hydride functional fuser oils, or mixtures thereof.
Alternatively, a blend of functional and nonfunctional fuser oils can be used. For example, in a blend of amino-fluid with fluoro-fluid, the amine groups enable reactivity with the fluoroelastomer substrate while the fluoro-fluid contributes excellent surface wetting characteristics.
A nonfunctional oil, as used herein, refers to oils that do not interact or chemically react with the surface of the fuser member or with fillers on the surface. A functional oil, as used herein, refers to a release agent having functional groups which chemically react with the fillers present on the surface of the fuser member, so as to reduce the surface energy of the fillers so as to provide better release of toner particles from the surface of the fuser member. If the surface energy is not reduced, the toner particles will tend to adhere to the fuser roll surface or to filler particles on the surface of the fuser roll, which will result in copy quality defects.
The disclosed fuser member works specifically well with toners with relatively high pile heights
With the disclosed fuser member, in embodiments, a gardiner gloss of from about 40 to about 100 ggu, or from about 60 to about 80 ggu can be obtained with respect to the fused toner image on the copy substrate. Gloss within these limits is highly desired from a customer standpoint.
All the patents and applications referred to herein are hereby specifically, and totally incorporated herein by reference in their entirety in the instant specification.
The following Examples further define and describe embodiments of the present invention. Unless otherwise indicated, all parts and percentages are by weight.
Formation of Fuser Member Coating
A fuser member coating formulation may be prepared from a solvent solution/dispersion containing 100 parts by weight of a hydrofluoroelastomer, DuPont VITON® GF (a tetrapolymer of 35 weight percent vinylidenefluoride, 34 weight percent hexafluoropropylene, 29 weight percent tetrafluoroethylene, and 2 weight percent of a cure site monomer). The VITON® GF may be mixed with 7 parts by weight of DuPont VITON® Curative 50, 1.5 parts by weight magnesium oxide (ELASTOMAG® 170 Special available from Rohm and Hass, Andover Mass.)Mass.), 0.75 parts by weight calcium hydroxide, 0.75 parts by weight carbon black (N990 available from R. T. Vanderbilt Co.), 4.89 parts by weight NOVEC® FC-4430 (available from 3M) and 0.86 parts by weight AKF-290 (available by Wacker) in a mixture of methylethylketone and methylisobutyl ketone. This coating formulation may be dispensed onto a fuser roll surface via flow coating to a nominal thickness of about 20 micrometers. The coating may be cured by stepwise heating in air at 95° C. for about 2 hours, 175° C. for about 2 hours, 205° C. for about 2 hours, and 230° C. for about 24 hours.
Formation of Fuser Member Coating Comprising Fluoroelastomer Outerlayer
Fuser roll topcoat formulations may be prepared identically to Example I with the exception of the application of a thin fluoropolymer outerlayer. An adhesive layer may need to be applied, possibly via brush coating, prior to application of this fluoropolymer outerlayer. This adhesive layer may be applied by metering the adhesive via a micro-pump as the fuser roll is rotated at a specific RPM. The fluoropolymer is flowcoated onto the fuser roll via flowcoating procedure documented in previous patents. This component is then cured either by Infrared (IR) curing or by convection oven via process in Example I followed by IR curing. The IR oven heat intensities should be set from about 50 to about 250° C. The heat intensity corresponds to about 2 times the voltage applied to the infrared lamps. The radiant energy curing time is generally selected to be about 5 to about 60 minutes.
While the invention has been described in detail with reference to specific and preferred embodiments, it will be appreciated that various modifications and variations will be apparent to the artisan. All such modifications and embodiments as may readily occur to one skilled in the art are intended to be within the scope of the appended claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 11/524,155, filed Sep. 19, 2006 from which priority is claimed, the disclosure of which is totally incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11524155 | Sep 2006 | US |
| Child | 11789981 | US |
