EP0740804A1 - Piece en couches pour transfert d'huile - Google Patents

Piece en couches pour transfert d'huile

Info

Publication number
EP0740804A1
EP0740804A1 EP95905709A EP95905709A EP0740804A1 EP 0740804 A1 EP0740804 A1 EP 0740804A1 EP 95905709 A EP95905709 A EP 95905709A EP 95905709 A EP95905709 A EP 95905709A EP 0740804 A1 EP0740804 A1 EP 0740804A1
Authority
EP
European Patent Office
Prior art keywords
oil
sheet material
component according
polytetrafluoroethylene
porous
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95905709A
Other languages
German (de)
English (en)
Inventor
Alistair Pitcairn
Francis Michael John Mccollam
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WL Gore and Associates UK Ltd
Original Assignee
WL Gore and Associates UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by WL Gore and Associates UK Ltd filed Critical WL Gore and Associates UK Ltd
Publication of EP0740804A1 publication Critical patent/EP0740804A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
    • G03G15/2014—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat
    • G03G15/2017—Structural details of the fixing unit in general, e.g. cooling means, heat shielding means
    • G03G15/2025—Structural details of the fixing unit in general, e.g. cooling means, heat shielding means with special means for lubricating and/or cleaning the fixing unit, e.g. applying offset preventing fluid
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/20—Details of the fixing device or porcess
    • G03G2215/2093—Release agent handling devices
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/20—Details of the fixing device or porcess
    • G03G2215/2093—Release agent handling devices
    • G03G2215/2096—Release agent handling devices using porous fluoropolymers for wicking the release agent

Definitions

  • the present invention relates to an oil transfer component for transferring oil to a roll in a fuser system of a copying machine, and if necessary for wiping excess toner from the roll.
  • copying machine as used herein relates to machines which employ heated fuser rolls, for example, plain-paper copying machines and laser printers.
  • toner images applied to the surface of paper or other recording medium are fixated by application of heat and pressure.
  • fixation is accomplished by passing the image-bearing recording medium between a hot thermal fixation roll and a pressure roll.
  • the toner material is directly contacted by a roll surface and a portion of the toner usually becomes adhered to the roll surface.
  • the adhered toner material may be redeposited on the recording medium resulting in undesirable offset images, stains, or smears; or in severe cases the recording medium may stick to the adhered toner material on the roll and become wrapped around the roll.
  • Toner pick-up by the rolls can be controlled by coating the surface of at least one of the rolls with a liquid release agent, such as a silicone oil.
  • release liquid it is important that the release liquid be applied uniformly and in precise quantities to the surface of the roll. Too little liquid or non-uniform surface coverage, will not prevent the toner from being picked up from the paper and deposited on the roll. On the other hand, excessive quantities of the release liquid may cause silicone rubber roll surfaces to swell and wrinkle, thus producing copies of unacceptable quality.
  • British published patent application 2242431 discloses a porous polytetrafluoroethylene structure used as a filter in industrial filtration.
  • the porous polytetrafluoroethylene material is produced by fusing particles of polytetrafluoroethylene such as to form a porous integral network of interconnected particles.
  • the disclosure of this patent specification is incorporated herein.
  • the web is supplied to a customer in this manner with one end wound on a feed spool and the other end attached to a take-up spool.
  • the web is slowly advanced from the feed spool to the take-up spool and is discarded once the feed spool is empty.
  • only a single thickness of the PTFE web is in operational contact with the fuser roll as the web is advanced.
  • an oil transfer component comprising multiple layers of PTFE web in direct contact with the fuser roll. Only a single thickness of web is used to apply oil and wipe off excess toner.
  • Patent publication EP0174474 shows a release oil applicator which comprises a porous body formed of PTFE held in a housing.
  • the PTFE body is saturated with silicone oil and may be formed with various cross-sections. However, only a single layer of PTFE is used.
  • Patent specification US 4336766 shows the use of a compound wick assembly formed from a relatively thick layer of Nomex felt and a relatively thin layer thereof.
  • the thick layer acts as a feeder to convey oil to the thinner layer.
  • the function of the oil reservoir is to hold quantities of liquid release agent for application to the roll of the fuser system.
  • the reservoir may be pre-loaded with a predetermined quantity of release oil. This is referred to as an "oil-filled device", and is generally discarded once the supply of liquid release agent is used up.
  • the device may be an "oil-fed” device which is supplied with liquid release agent on a continuous basis from a supply device.
  • the reservoir has to hold a finite quantity of liquid release agent and should have the ability to supply the liquid release agent at a suitable rate via the oil permeation control layer to the surface of the roll in the fuser system.
  • a reservoir material having a high void volume and thus a high porosity which enables it to hold relatively large quantities of liquid release agent may have a relatively low resistance to flow of the liquid release agent. Whilst to some extent this is obviated by the presence of the permeation control layer, problems can nonetheless arise.
  • the liquid release agent may run to the lowest point of the roller whilst the roller is stationary, such as between runs or overnight. This phenomena is known as "puddling" and leads to a non-uniform distribution of liquid release agent throughout the reservoir, which may in turn cause non-uniform application of release agent to the fuser system roll.
  • conventional reservoirs such as compressed fibres or open-cell foam materials may require costly processing steps to produce.
  • open-cell plastics foams it is usually necessary to mill the foam to the required shape, such as a block or roller.
  • Merely casting open-cell foams leaves a skin on the surface thereof which needs to be removed by machining or grinding in order to allow access of the liquid release agent to the foam and transference of the liquid release agent from the open-cell foam reservoir in use.
  • an oil transfer component which mitigates these problems can be provided by forming the oil transfer component as a plurality of contiguous layers of a porous polytetrafluoroethylene sheet material.
  • one aspect of the present invention provides an oil transfer component for transferring oil to a roll in a fuser system of a copying machine, which comprises: first and second contiguous layers of a sheet material, the first layer defining a roll- contacting face of the component for contacting said roll and transferring oil thereto, and the second layer underlying the first layer; the contiguous layers forming a unitary structure; and the sheet material comprising porous polytetrafluoroethylene.
  • the oil transfer component of the present invention is intended for holding and transferring oil to a roll in a fuser system, it also has the ability to remove excess oil if necessary. The oil transfer component may also wipe excess toner from the fuser system roll, particularly when the roll contacting face is textured.
  • the invention envisages the use of at least two contiguous layers of sheet material, more generally from three to twenty layers.
  • the number of layers employed will depend on the thickness of the sheet material but typically five to ten contiguous layers of sheet material may be used.
  • Each layer in itself constitutes a reservoir for holding and delivering release oil.
  • spaces may be defined between adjacent layers of sheet material which also act to contain release oil.
  • the component is simple to construct since a single material may be used to provide both the reservoir function and the oil permeation control functions of the prior art constructions.
  • the volume of the spaces between adjacent layers of sheet material will depend on the extent to which the contiguous layers are held in contact with each other. This volume is increased where the sheet material has at least one face which is textured. However, it is generally preferred that the faces of the sheet material be substantially smooth so as to allow the layers to be in close contact with each other.
  • At least some of the contiguous layers are formed from a single length of the sheet material. This is particularly the case when the oil transfer component is in the form of a roller which comprises a rotatable support having a single length of sheet material wound around the rotatable support. Alternatively, each layer may be made up of spirally wrapped overlapping turns. Such a construction is not limited to the production of cylindrical forms, but may also apply when the oil transfer component is in the form of a pad, when the pad may comprise a single length of sheet material wound into a pad of generally rectangular cross- section.
  • the single length of sheet material is generally wound in a single rotational direction under a predetermined tension.
  • the tension holds together the contiguous layers of sheet material and is one factor which defines the volume of the spaces between the adjacent layers.
  • the adjacent layers of sheet material may be bonded together. Bonding may be carried out by thermal fusion or by the use of a discontinuous pattern of adhesive.
  • a suitable adhesive is applied at the transverse edges of the length of sheet material.
  • the oil transfer component is in the form of a pad, and the contiguous layers are formed of separate pieces of such sheet material laid one on top of the other. Again, the separate pieces of sheet material require to be bonded together into a unitary structure.
  • the layers may be bonded together in any suitable manner known in the art, such as by the use of adhesives, by thermal fusion, by stitching etc..
  • the pattern of adhesive should preferably be a discontinuous pattern, such as a pattern of dots or lines, such as not to impede the flow of liquid release oil.
  • the oil transfer component is provided as a unitary structure for use as such.
  • the contiguous layers of porous polytetrafluoroethylene sheet remain contiguous during use and do not become separated (or unrolled as in prior constructions) .
  • the lower layer(s) act to retain oil and transfer it to the roll-contacting first layer during use.
  • the layers may be bonded together this is not essential to the operation of the component.
  • the presence of the oil (particularly after the component has become heated in use) and friction between the layers is sufficient to maintain a unitary structure.
  • the component is in the form of a roller, it may be arranged to rotate in the same direction as the sheet was wound onto the roller so as to resist unwinding. However, this is not always the best direction of rotation - which may be determined by experiment in individual cases.
  • the layers may be formed of the same or different types of porous polytetrafluoroethylene; for example a roller might have inner layers formed from one type of polytetrafluoroethylene and outer layers formed from a different type of polytetrafluoroethylene.
  • the first layer of sheet material defines a roll- contacting face, that is to say a face of the oil transfer component which contacts a roll (usually the fuser roll or the pressure roll) of the fuser system in use so as to apply liquid release oil thereto.
  • release oil is used herein in a general sense to include liquid release agents in general.
  • the second layer underlies the first layer in the sense of being in contact with the opposite face to the roll- contacting face but without implying any particular vertical orientation, and extends under substantially the entire roll-contacting face. Thus there are effectively at least two layers of sheet material beneath the roll-contacting face of the oil transfer component.
  • the thickness of the sheet material may be in the range 10 to 1000 microns. Very thin materials are not usually preferred since a large number of layers may be required. Conversely thick materials may give rise to a step formed by the free end of the sheet material in the case of a roller construction.
  • the particular advantage of the present invention is that the multiple layers of sheet material allow an oil transfer component to be manufactured in a particularly easy manner, the invention does not necessarily discount the possibility that the contiguous layers of sheet material may also be provided in conjunction with a conventional felt or open-cell foam reservoir as known in the prior art.
  • the sheet material is a porous polytetrafluoroethylene structure formed from particles of granular-type polytetrafluoroethylene fused together . such as to form a porous integral network of interconnected particles such as disclosed in Patent Specification GB2242431.
  • This material is able to withstand the high temperatures (around 200°C) encountered within the fuser system and has excellent mechanical properties and durability.
  • the sheet material has a thickness of 50 to 1500 microns, particularly 150 to 1000 microns.
  • the porous polytetrafluoroethylene structure is hydrophobic but has a high affinity for liquid release agents (referred to here generically as "release oil") such as silicone oil.
  • release oil liquid release agents
  • the layers of sheet material will be loaded with release oil before being assembled into the oil transfer component.
  • the oil transfer component will generally be supplied pre ⁇ loaded with release oil.
  • the component is discarded when this oil is substantially used up.
  • further oil is supplied thereto by means of an oil delivery mechanism.
  • the oil will constitute 10% to 70% by weight of the total weight of the oil-containing polytetrafluoroethylene structure of the oil transfer component, particularly 20% to 60% by weight.
  • the porous polytetrafluoroethylene structure usually has a specific gravity of 0.5 to 1.8, for example 0.6 to 1.5, typically 0.7 to 1.2 measured as described herein in Section (B) .
  • pure non-porous PTFE typically has a specific gravity of 2.16.
  • the porous polytetrafluoroethylene structure does not include any filler materials, since these are generally of mineral origin and tend to be of an abrasive nature which would damage the rolls in the fuser system.
  • the porous polytetrafluoroethylene structure may be produced as described in Patent Specification GB 2242431. It is particularly preferred to form the structure from a mixture of particles of different grades of granular- type polytetrafluoroethylene.
  • polytetrafluoroethylene PTFE
  • granular PTFE granular PTFE
  • fine powder PTFE
  • a particularly useful product for use in the present invention is formed from a mixture of unsintered and sintered granular type PTFE particles, for example 40% to 60% of Teflon (trademark) resin grade 7A; and 40% to 60% of Teflon resin grade 9B, respectively.
  • 0-100% unsintered PTFE e.g. grade 7A
  • 100-0% sintered PTFE e.g. grade 9B
  • Teflon granular-type resin grades 7A and 9B are available from DuPont Speciality Polymers Division, Wilmington, U.S.A.
  • the porous polytetrafluoroethylene structure is usually prepared by spraying onto a substrate, such as a ceramic tile or sheet of metal, and then peeling the formed structure from the substrate.
  • the sheet material is formed of porous polytetrafluoroethylene which has been expanded.
  • porous expanded polytetrafluoroethylene may be produced as disclosed in US 3,953,566.
  • a structure formed of so-called fine powder polytetrafluoroethylene is expanded along a single direction (i.e. monoaxially) or along two directions (i.e. biaxially expanded) usually at right angles to each other.
  • the expanded porous polytetrafluoroethylene sheet material generally has a pore size in the range 0.02 to 15 microns as measured by the bubble point method described herein. The choice of pore size may have an effect on the amount of release oil retained by the sheet material and its rate of delivery.
  • the problem of puddling discussed above is also mitigated by such expanded porous polytetrafluoroethylene.
  • the expanded porous polytetrafluoroethylene generally has a porosity determined from specific gravity measured as described herein in the range 10 to 98% (preferably 50 to 98%) and the porosity is also a parameter effecting the amount of release oil retained by the sheet material.
  • the thickness may be in the range 12 to 1000 microns, though very thin materials are less preferred since a large number of layers of sheet material may be required to build up a required thickness.
  • the oil will typically constitute 10 to 98% by weight of the oil-containing expanded polytetrafluoroethylene structure, particularly 20 to 70% by weight.
  • sheet material formed of other types of porous polytetrafluoroethylene may be used such as those formed of fibrous polytetrafluoroethylene wherein the polytetrafluoroethylene fibres are bonded into a porous matrix.
  • One such material is available under the Zitex trademark (Norton Chemplast, New Jersey, USA) .
  • Figure 1 is a schematic cross-sectional view of an oil transfer component in the form of a roller
  • Figure 2 is a further embodiment in the form of a roller having a conventional reservoir material, and several lavers of sheet material wound thereon;
  • Figure 3 is another embodiment in the form of a pad made up of a plurality of layers of sheet material bonded together;
  • Figure 4 is a cross-section of a still further embodiment in the form of a pad made by winding a single length of sheet material in a rectangular manner;
  • Figure 5 is a schematic elevation of the fuser section of a plain-paper copying machine employing a oil transfer component in the form of a roller;
  • Figure 6 is a schematic elevation of the fuser section of a different plain-paper copying machine which employs an oil transfer component in the form of a pad.
  • FIG. 1 shows in cross-section an oil transfer component according to the invention in the form of a roller 10.
  • the roller comprises a hollow cylindrical core 12 equipped with suitable bearings (not shown) for mounting in a copying machine.
  • the core 12 has a hollow interior 13 for containing release oil which is delivered therefrom via apertures 14 provided in the core.
  • the core could be formed of a sintered ceramic material.
  • a single length 16 of sheet material is wound around the outside of the core so as to form six contiguous layers (17a, 17b, 17c etc. ) .
  • an adhesive is applied along a marginal portion of the length of sheet material so that the contiguous layers become adhered together at the ends of the cylindrical roller.
  • the free end 18 of the length of sheet material is adhered to the underlying layer to prevent it coming loose in use.
  • the length of sheet material had a width sufficient to cover the desired area on the roller. That is to say the width of the sheet material provides the full width of the oil transfer component.
  • the length of sheet material may in an alternative embodiment be spirally wound in a series of overlapping turns on to the roller core so as to build up the desired width and thickness.
  • a single length of porous polytetrafluoroethylene sheet produced as described in Example 1 was wound onto a hollow aluminium core having four rows of 3mm diameter oil delivery apertures arranged at 90° apart around the circumference thereof.
  • the thickness of the sheet was about 375 microns.
  • the porous polytetrafluoroethylene had a length of 545 mm and a width of 365 mm.
  • both ends of the sheet were cut with a knife inclined at about 30"C to the horizontal in order to chamfer the ends.
  • the ends could be feathered by abrading with sandpaper.
  • One end was adhered to the aluminium core using two lines of silicone sealant RTV732 (Dow Corning) .
  • 60,000 cS silicone release oil (Dow Corning 200) was spread evenly over the flat porous polytetrafluoroethylene sheet and left for one hour to allow the oil to soak into the sheet.
  • the aluminium core was then rolled up so as to wrap the porous polytetrafluoroethylene sheet around the core in about eight turns, the textured surface of the polytetrafluoroethylene being outermost.
  • the ends of the cylindrical roller were then sealed with RTV732 silicone sealant so as to seal together the margins of the polytetrafluoroethylene sheet, and the sealant allowed to cure at room temperature. The free end of the polytetrafluoroethylene length was not adhered to the layer beneath.
  • the weight of the core and dry polytetrafluoroethylene sheet was 141 g, and the weight of oil applied was 29 g.
  • the core diameter was about 22mm and 27mm after wrapping the polytetrafluoroethylene sheet around.
  • This roller was then fitted into a Kodak Ektoprint 300 copier and run for 250,000 copies giving satisfactory copy quality. This exceeds the number of copies which can be handled using a conventional roller formed of Nomex (trademark) aramid felt.
  • Figure 2 is a cross-section of a roller 20 having a core 12 as before. This differs from the embodiment shown in Figure 1 in that a hollow sleeve 22 of known reservoir material, such as a felt formed of Nomex fibres or an open-cell foam plastics material is employed.
  • the fibres sold under the Nomex trademark are aramid fibres, a type of polyamide.
  • the open-cell foam might be an open-cell melamine foam.
  • the hollow sleeve 22 could itself be formed of a length of one type of porous polytetrafluoroethylene (e.g. from 100% Teflon grade 9B) and the outer length 16 from a different type of porous polytetrafluoroethylene (e.g. from 50% grade 7A and 50% grade 9B) .
  • Figure 3 is a cross-section of a pad 30 formed of a plurality of contiguous layers 32 of sheet material. The layers are bonded together by means of a pattern of adhesive dots.
  • the adhesive may be silicone adhesive as mentioned above. It will be noted that the roll- contacting face 34 of the oil transfer pad 30 is slightly curved so as to follow the curvature of the roll in the fuser system on to which the pad transfers release oil in use.
  • Figure 4 also shows an oil transfer component in the form of a pad having a roll-contacting face 34.
  • the pad has a substantially rectangular cross-section and has been formed by winding a single length of sheet material (16) in a substantially rectangular manner.
  • it may be convenient to wind the length of sheet material about a flat central former, which former may be left in place or may be withdrawn after production of the oil transfer pad.
  • FIGs 5 and 6 show fuser systems employing oil transfer components according to the present invention either in the form of a roller 10 (or roller 20) or a pad 30 (or pad 40) .
  • the fuser system comprises a PTFE-covered (or silicone rubber covered) fuser roll 2 and a silicone rubber covered pressure roll 4, which are oiled and wiped by means of an oil transfer component of the present invention.
  • oil is applied directly on to the fuser roll 2 by means of the oil transfer roller 10.
  • release oil is applied to the fuser roller 2 by means of a pad 30 held within a channel 42. In both cases, the release oil may be applied to the pressure roll 4 instead of the fuser roll 2, if desired.
  • the oil transfer components may either be provided as oil-filled components, that is to say they contain a predetermined quantity of silicone release oil and are discarded after the release oil is used up; or may be provided as an oil- fed type, in which case a supply of release oil is constantly fed to the oil transfer component (which is usually supplied pre-loaded with release oil) by a conventional oil delivery means (not shown) .
  • the sheet material was a porous polytetrafluoroethylene sheet made as follows:
  • the above suspension was sprayed on to a smooth stainless steel plate to a nominal net film thickness of 1000 microns using a Binks BBR spray gun and L88 pressure cup, then dried in an oven.
  • the air temperature was brought up to 115°C and when the temperature of the stainless steel plate had reached 100°C drying was continued for 30 ins.
  • the air temperature was then progressively increased over a few hours up to 365°C. Once the plate temperature had reached 350°C drying was continued for a further 2.5 hrs.
  • the resultant structure was then cooled.
  • the specific gravity was 0.80 g/cc.
  • the PTFE sheet was carefully peeled from the stainless steel plate.
  • the thickness was about 750 microns.
  • the lower face which had been in contact with the stainless steel plate was smooth and the upper face was slightly textured as a result of the spray application.
  • the oil retention capacity could be modified by varying the proportion of Teflon grade 7A from 50% by weight upto 100% by weight.
  • the proportion of grade 7A could vary from 0% to 100% by weight depending on the desired properties of the PTFE sheet.
  • 100% grade 9B the suspension was sprayed onto a fine stainless steel mesh to anchor the material and resist shrinkage during baking; and was then peeled off.
  • Nomex (trademark) felt were compared with two types of porous PTFE sheet material produced in the manner of Example 1:
  • the weight/area was measured according to ASTM 0461-87 (Section 11) and the thickness was measured according to ASTM D461-87 (Section 10) .
  • the density was calculated as the weight/area divided by lOOOx thickness. This method of measuring the density was adopted for this comparison example (rather than the method given in Section (B) herein) in order to allow valid density measurements for the comparison Nomex felt to be made.
  • Example 2 does not give an indication as to the distribution of oil within the materials' structures.
  • Nomex 1 Upper 1.6392 25mmx75mm 1.6192 0.20
  • An oil transfer component according to the present invention which is formed of multiple layers of the porous PTFE sheet material has a markedly reduced tendency for the oil to puddle when the copying machine is not operating.
  • TEFLON (trademark) granular-type PTFE fluorocarbon resin grades 7A and 9B are available from DuPont Speciality Polymers Division, Wilmington U.S.A.
  • Grade 9B is a premelted sintered resin. The manufacturers product specification indicates an average specific gravity of 2.16, and an average particle size of 35 microns (grade 7A) and 500 microns (grade 9B prior to milling) .
  • PTFE grade 7A was unsintered and was used as supplied.
  • the PTFE grade 9B was milled to a weight average particle size of about 40 microns by grinding an aqueous slurry thereof between grinding stones at room temperature as follows.
  • the PTFE grade 9B was mixed with water to form a slurry, and the slurry fed between closely spaced grinding surfaces of a grinding mill as disclosed in US- A-4841623, to crush and shear the pieces of PTFE into particles.
  • the ground slurry was then filtered or centrifuged to separate the porous expanded PTFE particles from water, and the separated finely ground particles were oven dried at from 125°C - 150°C.
  • the specific gravity of the PTFE sheet is determined by weighing a sample thereof in two different media, viz; air and water. The weights were determined using an Avery VA124 analytical balance. The specific gravity is calculated as being equal to (weight in air)/(weight in air - weight in water).
  • Particle size of ground PTFE grade 9B was determined as follows: using a magnetic stirrer and ultrasonic agitation, 2.5 grams of milled PTFE powder were dispersed in 60 ml isopropyl alcohol. (Ultrasonic Probe Model W- 385, manufactured by Heat Systems-Ultrasonics, Inc.) . Aliquots of 4-6ml of the dispersed particles were added to approximately 250ml of circulating isopropyl alcohol in a Leeds & Northup Microtrac FRA Particle Size Analyzer of analysis. Each analysis consisted of three 30-second runs at a sample circulation rate of 2 litres/minute during which light scattering by the dispersed particles is automatically measured and the particle size distribution automatically calculated from the measurements. ( D) Pore Size
  • Pore size of expanded polytetrafluoroethylene was determined from the bubble point, defined in this patent as the pressure required to blow the first bubble of air detectable by its rise through a layer of liquid covering the sample.
  • a test device similar to the one employed in ASTM F316-80, was used consisting of a filter holder, manifold and pressure gauge (maximum gauge pressure of 275.8 kPa) .
  • the filter holder consisted of a base, a locking ring, an o-ring seal, support disk and air inlet.
  • the support disk consisted of a 150 micron mesh screen and a perforated metal plate for rigidity.
  • the effective area of the test sample was 8.0 plus or minus 0.5 cm 2 .
  • test sample was mounted on the filter holder and wet with anhydrous methanol until clarified.
  • the support screen was then placed on top of the sample and the top half of the filter holder was tightened in place.
  • Approximately 2 cm of anhydrous methanol at 21°C was poured over the test sample.
  • the pressure on the test sample was then gradually and uniformly increased by the operator until the first steady stream of bubbles through the anhydrous methanol were visible. Random bubbles or bubble stream of the outside edges were ignored.
  • the bubble point was read directly from the pressure gauge.
  • the oil used was Dow Corning 200 silicone oil of viscosity 100 centistokes and a density of 0.96 g/cc.
  • Test samples of size 25mm x 150mm were cut at random from the sheet material. Each sample was weighed to the nearest O.Olg. The samples were placed on the surface of a vessel which had been fitted with oil to a depth of 50mm and allowed to sink under gravity to avoid air entrapment. The samples remained immersed for 3 hours. Thereafter each sample was removed from the oil and hung from a wire hook with the long dimension vertical to drain for 60 ins. A stirring rod was used to remove any visible drops of oil adhering to the sample before weighing the sample.
  • the oil retention was calculated according to ASTM D461-37 Section 21.6.1.
  • the oil-containing sample was weighed to an accuracy of O.Olg to give an initial weight.
  • the sample was then immersed in methylene chloride at a temperature of 20 ⁇ 2°C and agitated for 1 minute.
  • the sample was then removed and hung in an oven at 110°C for 15 minutes. This procedure was repeated until a constant weight (measured to O.Olg accuracy) was achieved; giving the final weight.
  • the net oil content was calculated from the difference between the initial and final weights of the sample.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Laminated Bodies (AREA)
  • Fixing For Electrophotography (AREA)
  • Fats And Perfumes (AREA)

Abstract

Pièce destinée à transférer de l'huile à un rouleau (2) dans un système fixeur d'une machine d'impression, telle qu'une photocopieuse ou une imprimante laser, qui est constituée de couches contiguës (17a, 17b, 17c, etc.) de feuilles de polytétrafluoroéthylène, dont le nombre va en général de trois à vingt. Ladite pièce peut être fabriquée par enroulement de tours d'une seule bande autour d'une partie centrale (par ex. dans le cas d'un rouleau (10)) ou être constituée de feuilles séparées (32). Le polytétrafluoroéthylène poreux peut être formé de particules de polytétrafluoroéthylène de type granulaire agrégées par fusion pour former un réseau poreux monobloc ou peut être un polytétrafluoroéthylène expansé poreux. Ladite pièce de transfert d'huile est facile à produire et possède d'excellentes propriétés d'alimentation en huile et d'essuyage du toner; elle résiste en outre à l'accumulation d'huile.
EP95905709A 1994-01-19 1995-01-17 Piece en couches pour transfert d'huile Withdrawn EP0740804A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9400934 1994-01-19
GB9400934A GB9400934D0 (en) 1994-01-19 1994-01-19 Layered oil transfer component
PCT/GB1995/000082 WO1995020186A1 (fr) 1994-01-19 1995-01-17 Piece en couches pour transfert d'huile

Publications (1)

Publication Number Publication Date
EP0740804A1 true EP0740804A1 (fr) 1996-11-06

Family

ID=10748992

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95905709A Withdrawn EP0740804A1 (fr) 1994-01-19 1995-01-17 Piece en couches pour transfert d'huile

Country Status (6)

Country Link
EP (1) EP0740804A1 (fr)
JP (1) JPH09509259A (fr)
AU (1) AU1421995A (fr)
CA (1) CA2178638A1 (fr)
GB (2) GB9400934D0 (fr)
WO (1) WO1995020186A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU711872B2 (en) * 1995-06-07 1999-10-21 W.L. Gore & Associates (Uk) Ltd. Porous composite
US5779795A (en) * 1995-08-04 1998-07-14 W. L. Gore & Associates, Inc. Low surface energy fluid metering and coating device
JP3699299B2 (ja) 1999-07-05 2005-09-28 ニチアス株式会社 オイル塗布装置

Family Cites Families (8)

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Publication number Priority date Publication date Assignee Title
US4336766A (en) * 1980-11-24 1982-06-29 Xerox Corporation Roll fusing apparatus for electrophotography and release agent management system therefor
JPS59214062A (ja) * 1983-05-19 1984-12-03 Sumitomo Electric Ind Ltd 複写機の離型剤塗布装置
CA1240832A (fr) * 1984-05-23 1988-08-23 Thomas F. Szlucha Meche pour organe de fusion
JPS6161663A (ja) * 1984-08-31 1986-03-29 Sumitomo Electric Ind Ltd 離型剤塗布装置
US4908670A (en) * 1988-06-20 1990-03-13 Eastman Kodak Company Wick for fixing roller
GB9122750D0 (en) * 1991-10-26 1991-12-11 Gore W L & Ass Uk Oil transfer component
US5267004A (en) * 1991-12-18 1993-11-30 Eastman Kodak Company Rotating wick for fusing apparatus having improved oil laydown
GB9207571D0 (en) * 1992-04-07 1992-05-20 Gore W L & Ass Uk Oil reservoir

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9520186A1 *

Also Published As

Publication number Publication date
GB9400934D0 (en) 1994-03-16
JPH09509259A (ja) 1997-09-16
GB2285768B (en) 1997-09-17
AU1421995A (en) 1995-08-08
WO1995020186A1 (fr) 1995-07-27
CA2178638A1 (fr) 1995-07-27
GB9500817D0 (en) 1995-03-08
GB2285768A (en) 1995-07-26

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