EP1014220A1 - A fusing member for hot pressure fixing of toner particles and for transfusing toner particles - Google Patents

A fusing member for hot pressure fixing of toner particles and for transfusing toner particles Download PDF

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Publication number
EP1014220A1
EP1014220A1 EP98204368A EP98204368A EP1014220A1 EP 1014220 A1 EP1014220 A1 EP 1014220A1 EP 98204368 A EP98204368 A EP 98204368A EP 98204368 A EP98204368 A EP 98204368A EP 1014220 A1 EP1014220 A1 EP 1014220A1
Authority
EP
European Patent Office
Prior art keywords
layer
fusing
outermost layer
support
fusing member
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Withdrawn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
EP98204368A
Other languages
German (de)
French (fr)
Inventor
Stefaan De Meutter
Serge Tavernier
Danny Van Wunsel
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.)
Xeikon NV
Original Assignee
Agfa Gevaert NV
Xeikon NV
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 Agfa Gevaert NV, Xeikon NV filed Critical Agfa Gevaert NV
Priority to EP98204368A priority Critical patent/EP1014220A1/en
Priority to US09/461,368 priority patent/US6365279B1/en
Publication of EP1014220A1 publication Critical patent/EP1014220A1/en
Withdrawn legal-status Critical Current

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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
    • G03G15/2053—Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating
    • G03G15/2057—Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating relating to the chemical composition of the heat element and layers thereof

Definitions

  • This invention relates to a member that can be used as a fusing roller for hot pressure fixing of toner particles or as an intermediate member in transfuse systems. It relates in particular to such a roller with specified elastomeric layers, in particular silicone rubbers.
  • the toner image formed on the photoconductor can be transferred directly to the final image receiver, e.g. plain paper whereon it is fixed by fusing the toner particles by heat and pressure using fixing rollers.
  • the toner image formed on the photoconductor or brought on a means for collecting the colour separations when performing colour printing can be transferred not directly to the final image receiving member but in a first transfer zone to an intermediate member that can be heated and from that intermediate member to the final image receiving member whereon it is fixed by the heating of the intermediate member that is pressed against the final image receiving member by a pressure means.
  • This latter process is further on termed as a "transfuse" and the intermediate member is designated by "transfusing member".
  • Fusing and fixing of toner particles to a substrate by simultaneous application of heat and pressure are well known in the art and also fusing rollers for use in hot pressure fixing of toner particles are well known.
  • a fusing roller is disclosed with a base member and thereon a first layer of an heat resistant resin and on top of the first layer a layer of silicone rubber.
  • a fuser member with a base material and two elastomer layers thereon the outer elastomer layer containing a metal filler is disclosed.
  • a multi-layered fusing member is disclosed. This member has in sequential order a base support member, an adhesive layer, a tie coat layer and an outer elastomeric fusing layer with therein a copolymer with vinylidene fluoride and a metal oxide.
  • transfusing members are well known in the art. When transfusing members are in contact with the photoconductor it is important that the photoconductor is not soiled by impurities present in the final imaging member. Therefore transfusing members comprising two layers, a top layer permeable for the impurities and a layer under the top layer absorbing the impurities have been disclosed.
  • a transfusing member consisting of a metal roller provided with a first covering of pigmented RTV silicone rubber (RTV201/200, wherein silica particles are present) and a second covering of non-pigmented silicone rubber obtained by cross-linking an ⁇ , ⁇ -hydroxy-polymethylsiloxane with a tetra-ethyl silicate under influence of di-butyl tin dilaurate.
  • RTV201/200 pigmented RTV silicone rubber
  • non-pigmented silicone rubber obtained by cross-linking an ⁇ , ⁇ -hydroxy-polymethylsiloxane with a tetra-ethyl silicate under influence of di-butyl tin dilaurate.
  • a transfusing member consisting of a support with a pigmented rubber layer, wherein the pigment is preferably carbon black, and a top layer of silicone rubber.
  • a release agent most frequently a silicone oil, is applied to the fusing or transfusing members to prevent hot-offset (i.e. toner particles adhering to the surface of the fusing or transfusing members instead of to the substrate) and to enhance the lifetime of the surface of the fusing and transfusing members.
  • release agent can however create problems in the finished image, basically because it gives kind of gloss to the image and that, when the release agent is not evenly spread over the image differences in gloss appear.
  • release agents frequently entails problems of streaks, oily look, patchiness, etc. in the finished image.
  • silicone oil is applied to a transfusing member that comes in direct contact with the photoconductor, the photoconductor can be soiled by the silicone oil and therefore it is important that the use external release agent can be minimised or preferably avoided.
  • a fusing member comprising a support, and on said support,
  • fusing member will be used to indicate both a fusing member and a transfusing member. It was now found, after experimentation, that it was possible to design a member that could be used as fusing member with a very low amount of external release agent, e.g. silicone oil, or even without any external release agent and still had a long lifetime and did not show hot-offset.
  • external release agent e.g. silicone oil
  • the fusing member as in the prior art, comprised two layers on a support wherein an outermost layer containing at most 5 % by weight of an inorganic filler is in direct contact with a second impurity absorbing layer wherein preferably at least 5 % by weight of metal oxide particles are present.
  • the outermost layer of the fusing member according to this invention had to be quite soft.
  • the outermost layer is chosen to be quite hard (e.g. a hardness equal to or larger than 40 Shore A)
  • fusing members having an outermost layer being between 5 and 500 ⁇ m thick, with a degree of swelling factor equal to or higher than 3 % gave better results in terms of avoiding hot-offset than the harder prior art outermost layers.
  • the swelling factor is in the case of an outermost layer according to this invention an indication of the softness, a layer with a high swelling factor is quite soft.
  • an outermost layer in a fusing member according to this invention has a swelling factor, SF, equal to or larger than 3 , more preferably SF ⁇ 5.
  • the swelling factor is measured as follows : The thickness of a self-supporting sample of the outermost layer measuring about 20 mm x 3 mm is measured to an accuracy of 0.1 ⁇ m. This is the value Th d , standing for dry thickness. Afterwards the self-supporting sample is wetted with toluene and the sample is allowed to swell for 3 minutes, then the excess toluene is wiped and the thickness of the swollen sample is again measured to an accuracy of 0.1 ⁇ m. This is the value Th w .
  • the swelling factor, SF is Th w /Th d .
  • an inorganic filler Preferably at most 5 % by weight of an inorganic filler is added to the outermost layer, more preferably at most 2 % by weight of an inorganic filler is added and in an even more preferred embodiment, it no inorganic filler at all is deliberately added to the outermost layer, so that it contain no inorganic filler, except for possible impurities that can be present in the other ingredients of the layer .
  • peeling force is the force necessary to peel a TESA 4163 tape away from the outermost layer at a speed of 30 cm/min.
  • the outermost layer which is preferably the outermost layer of the fusing member that comes in direct contact with the toner particles, contains preferably at least 80 % by weight of a silicone elastomer (silicone rubber) being loosely cross-linked and forming a kind of network having a low amount of cross-links.
  • the outermost layer may further contain, imbedded in said network a silicone oil with a molecular weight equal to or larger than 50,000.
  • a well suited silicone oil is, e.g., the silicone oil sold by ABCR GmbH, Düsseldorf, Germany under trade name DGM-000.
  • Very well suited elastomers for forming the outermost layer in a fusing member of this invention, are RTV or loosely cross-linked silicone elastomers formed by poly-addition of a organopolysiloxane with average molecular weight ⁇ 300,000 and/or an organopolysiloxane gum with average molecular weight > 300,000 having an alkenyl group, preferably at least two alkenyl groups, which are preferably vinyl groups.
  • the latter silicone rubbers are preferred.
  • Very preferred silicone rubbers for use in the outermost layer of a fusing member of this invention are silicone rubbers produced by cross-linking of organopolysiloxanes containing more than 0.005 milli-equivalent of vinyl groups per g and less than 0.1 milli-equivalent of vinyl groups per g. More preferably the content of vinyl groups in organopolysiloxanes, useful for forming the outermost layer of a fusing member of this invention, is between 0.005 and 0.05 milli-equivalent of vinyl groups per g. The equivalent value of vinyl groups is calculated by dividing the number of vinyl groups in the organopolysiloxane by the molecular weight of the organopolysiloxane.
  • the outermost layer can comprise a mixture of organopolysiloxanes with free alkenyl groups.
  • the average alkenyl content of the mixture is preferably between 0.005 milli-equivalent and 0.1 milli-equivalent of vinyl groups per g. More preferably the average content of vinyl groups in such a mixture of organopolysiloxanes, is between 0.005 and 0.05 milli-equivalent of vinyl groups per g.
  • the vinyl groups on the organopolysiloxane can be terminal groups or the vinyl groups can be side groups in the organopolysiloxane.
  • Organopolysiloxanes with an alkenyl group and with average molecular weight ⁇ 300,000 are commercially available, e.g., from Rhone-Poulenc under trade name SILCOLEASE 7420, SILCOLEASE 7440, from ABCR, Düsseldorf, Germany under trade name VGM-021.
  • Organopolysiloxane guns with an alkenyl group and with average molecular weight > 300,000 commercially available, e.g., from ABCR, Düsseldorf, Germany under trade name DMS-V41, DMS-V46 and VDT-153.
  • the outermost layers in a fusing member according to this invention are frequently applied from a coating solution by dip-coating or by ring-coating.
  • a coating solution by dip-coating or by ring-coating.
  • the organopolysiloxane with an alkenyl group and with average molecular weight ⁇ 300,000 and an organopolysiloxane gum with an alkenyl group and with average molecular weight > 300,000, forming the outermost layer of a fusing member according to this invention can be hardened by reaction with an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule.
  • an hardener of this type it is added to the coating solution so that between 0.5 to 20 moles of hydrogen atoms direct bound to a Si-atom are present per mole of the alkenyl groups.
  • Typical examples are :
  • the cross-linking reaction can be speeded up by addition of a Pt-catalyser an a concentration between 0.1 to 500 ppm with respect to the total amount of organopolysiloxanes.
  • the outermost layer can comprise further additives, if so desired, e.g. cure retardants, heat stabilisers, flame retardants, plasticisers, anti-static agents, electric conductive compounds, etc.
  • further additives e.g. cure retardants, heat stabilisers, flame retardants, plasticisers, anti-static agents, electric conductive compounds, etc.
  • the second layer immediately in contact with the outermost layer
  • the second layer comprises preferably at least 80 % by weight of a silicone rubber and preferably at least 5 % by weight of inorganic filler particles with specific surface of at least 30 m 2 /g, more preferably said particles have a specific surface of at least 50 m 2 /g and even more preferably said particles have a specific surface of at least 100 m 2 /g.
  • This filler can be SiO 2 , TiO 2 , Al 2 O 3 , a pigment as, e.g. Cu-phthalocyanine.
  • the inorganic filler with specific surface of at least 30 m 2 /g is a member selected from the group consisting of SiO 2 , TiO 2 , and Al 2 O 3 .
  • the presence of the filler aids the fusing member to absorb compounds coming from the heated toner particles and/or the heated image receiving member that soil the surface of the fusing member and that penetrate the outermost layer. Thus the surface of the fusing member stays clean for a longer time of use.
  • the second layer is in a fusing member of this invention mostly used as the layer for transporting the thermal energy needed to fuse the toner particles from a source of heat towards the outermost layer. Therefore the thermal conductivity of the second layer is at least 0.4 W/m.K (measured according to DIN 52612 in Watt per meter times degree Kelvin), preferably the thermal conductivity of the second layer is at least 0.7 W/m.K .
  • the high thermal conductivity is beneficial for cold offset, which means that when the fusing member has a second layer with high thermal conductivity the fusing process of the toner particles starts a lower temperatures.
  • this second layer further comprises preferably inorganic filler particles having an average volume diameter of at least 1 ⁇ m, this larger filler particles can be silica, CuO, Fe 2 O 3 , Al 2 O 3 etc.
  • the support in a fusing member of the present invention can be any support known in the art.
  • a metal support e.g. aluminium, stainless steel, etc., are preferred supports.
  • the support can be in the form of a roller, which can be a hollow metal (e.g. Al, Stainless steel, etc.) cylinder incorporating an heating source or in the form of an endless belt.
  • a roller which can be a hollow metal (e.g. Al, Stainless steel, etc.) cylinder incorporating an heating source or in the form of an endless belt.
  • the fusing member of this invention can be used in a fusing device as a heated fixing roller coupled to a pressure roller for hot pressure fixing of the toner particles.
  • the amount of filler that can incorporated in the second layer depends whether the fusing member is used as nip-forming roller or not.
  • the fusing member of this invention is used as nip-forming roller, then the amount of filler is restricted by the need for having a good elasticity of the nip-forming roller.
  • the pressure roller is used as nip forming roller, more filler can be added to the second layer which makes it possible to have a second layer with high thermal conductivity.
  • a fusing member of this invention is coupled, as fixing roller, to a pressure roller for hot pressure fixing of the toner particles that the pressure roller is the nip-forming roller, so that a second layer with high thermal conductivity can be used in the fusing member.
  • the fixing roller is the heated roller in the couple fixing roller/pressure roller and it is usually heated from inside the support (which is most frequently an hollow cylinder) a second layer with high thermal conductivity is beneficial for bringing the heat rapidly to the surface of the fixing roller which in turn allows for higher fixing speed.
  • a fusing member of this invention can also be used as a transfusing member, in this case the toner image present on a photoconductor or on an intermediate member is not directly transferred to a final image receiving substrate and fixed there, but is first transferred to a transfusing member, from where it is further, in one step transferred and fixed to the final image receiving member.
  • An printer using toner particles in a transfuse system is more complicated than a printer wherein direct transfer proceeds, but a transfuse system has the advantage that lower fixing temperature can be used.
  • a toner image, developed on the photoconductor is often first transferred to an intermediate member, e.g. a belt or roller made from non-soiling material, as metal or a polymer, and from said intermediate member to the transfuse member.
  • An intermediate member e.g. a belt or roller made from non-soiling material, as metal or a polymer
  • a fusing member of this invention can be used as transfusing member in printers with direct contact between the photoconductor as well as in printers wherein the image is transferred from the photoconductor to the transfusing member over an intermediate non-soiling member.
  • a fusing member according to this invention can be used in any imaging method using toner particles, e.g., electrophotography, direct electrostatic printing, ionography, magnetography, etc.
  • a fusing member of this invention is particularly well suited in imaging method using dry toner particles with an average volume diameter between 2 and 20 ⁇ m.
  • a fusing member of the present invention can be used with printers wherein the final image receiving substrate is in sheet form as well as in printers wherein the final image receiving substrate is in web form.
  • a fusing member of this invention can most beneficially be used in the latter printers.
  • a fusing member of this invention can be used both a fusing roller as well as transfusing member with very low amounts of external release agent, the invention also encompasses an imaging method comprising the steps of :
  • the fusing members are used in the examples as fusing rollers, to fuse, without applying any external release agent to the surface, commercially available CHROMAPRESS (trade name of Agfa-Gevaert NV, Mortsel Belgium) toner to 4CC-ART paper of 115 g/m2 (trade name of ENSO).
  • CHROMAPRESS trade name of Agfa-Gevaert NV, Mortsel Belgium
  • a fixing window was determined by taking the temperature were fusing starts (the end of ,the cold offset) and the temperature at which hot offset sets on is determined after printing 100 sheets of paper in DIN A3 format and after printing 2000 sheets of paper in DIN A3 format, normal fixing proceeded at 145 °C.
  • the fusing members were also used in an experimental transfuse set-up.
  • An electrostatic latent image was developed on a photoconductor by commercially available CHROMAPRESS (trade name of Agfa-Gevaert NV, Mortsel Belgium) toner, the developed image was transferred from there to a transfusing member with a construction according to this invention, and then further transferred to plain paper 4CC-ART paper of 115 g/m2 (trade name of ENSO).
  • the transfusing member was heated and was used without any external release agent applied to its surface.
  • a fixing window was determined by taking the temperature were fusing starts (the end of the cold offset) and the temperature at which hot offset sets on is determined after printing 100 sheets of paper in DIN A3 format and after printing 7200 sheets of paper in DIN A3 format, normal transfusing took place at 120 °C.
  • the results are given in table 1.
  • the peel force in N/m was also determined according to Finat No 3, with Tape TESA 4163 at a peeling speed of 30 cm/min.
  • the same second layer (closest to the support) was used. It was prepared by mixing 150 g of SLE5900 (trade name of general Electric, USA for a silicone rubber containing fine silica particles having specific surface > 30 m2/g) part A and 150 g of SLE5900 part B are with 75 g of iso-octane 100. The solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 70 ⁇ m thick. The thermal conductivity of this second layer was 0.18 W/m.K.
  • Example 4 was repeated except for the second layer.
  • the second layer was prepared by mixing 60 g of SILCOSEAL RTV 201 containing silica having specific surface > 30 m2/g, (trace name of General Electric) and 20 g cyclohexane. 6 g of VERNETZER A21 (trade name of Rhodia) was further added to the solution. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 60 minutes at 100 °C. This gave a second layer being 100 ⁇ m thick. The thermal conductivity of this second layer was 0.18 W/m.K.
  • Example 4 was repeated except for the second layer.
  • the second layer was prepared by mixing 100 g of TSE-3331A and 100 g of TSE-3331B containing carbon particles with, (trade names of General Electric). This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 60 minutes at 100 °C. This gave a second layer being 250 ⁇ m thick. The thermal conductivity of this second layer was 0.63 W/m.K.
  • the thermal conductivity of the second layer is quite important for allowing rapid fixing at fairly low temperatures, as indicated by the following examples.
  • Example 4 was repeated except for the second layer.
  • the second layer was prepared by mixing 90 g of TSE-389 containing fine silica particles having specific surface > 30 m2/g, (trade name of General Electric) and 10 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 100 ⁇ m thick. The thermal conductivity of this second layer was 0.18 W/m.K.
  • Example 4 was repeated except for the second layer.
  • the second layer was prepared by mixing 40 g of TSE-326 containing a metal oxide having a diameter larger than 1 ⁇ m, (trade name of General Electric) and 10 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 50 ⁇ m thick. The thermal conductivity of this second layer was 0.43 W/m.K.
  • Example 4 was repeated except for the second layer.
  • the second layer was prepared by mixing 142.5 g of TSE-3280G containing a metal oxide having a diameter larger than 1 ⁇ m, (trade name of General Electric) and 7.5 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 50 ⁇ m thick. The thermal conductivity of this second layer was 0.88 W/m.K.

Abstract

A fusing member comprising a support, and on the support,
  • an outermost layer containing a silicone elastomer, having at most 5 % by weight of filler particles, the elastomer layer containing polyorganosiloxane having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
  • a second layer with an impurity absorbing material, closer to the support and immediately in contact with the outermost layer, the second layer being at least 40 µm thick.
    Preferably the second layer has a silicone containing elastomer and contains at least 5 % by weight of metal oxide particles having a specific surface of ≥ 30 m2.
    •

    Description

    FIELD OF THE INVENTION
    This invention relates to a member that can be used as a fusing roller for hot pressure fixing of toner particles or as an intermediate member in transfuse systems. It relates in particular to such a roller with specified elastomeric layers, in particular silicone rubbers.
    BACKGROUND OF THE INVENTION
    In electro(photo)graphic copiers or printers, the toner image formed on the photoconductor can be transferred directly to the final image receiver, e.g. plain paper whereon it is fixed by fusing the toner particles by heat and pressure using fixing rollers. The toner image formed on the photoconductor or brought on a means for collecting the colour separations when performing colour printing, can be transferred not directly to the final image receiving member but in a first transfer zone to an intermediate member that can be heated and from that intermediate member to the final image receiving member whereon it is fixed by the heating of the intermediate member that is pressed against the final image receiving member by a pressure means. This latter process is further on termed as a "transfuse" and the intermediate member is designated by "transfusing member".
    Fusing and fixing of toner particles to a substrate by simultaneous application of heat and pressure are well known in the art and also fusing rollers for use in hot pressure fixing of toner particles are well known.
    In, e.g., US-A-4 078 286 a fusing roller is disclosed with a base member and thereon a first layer of an heat resistant resin and on top of the first layer a layer of silicone rubber.
    In US-A-4 257 699 a fuser member with a base material and two elastomer layers thereon, the outer elastomer layer containing a metal filler is disclosed. In US-A-5 049 444 a multi-layered fusing member is disclosed. This member has in sequential order a base support member, an adhesive layer, a tie coat layer and an outer elastomeric fusing layer with therein a copolymer with vinylidene fluoride and a metal oxide.
    Also transfusing members are well known in the art. When transfusing members are in contact with the photoconductor it is important that the photoconductor is not soiled by impurities present in the final imaging member. Therefore transfusing members comprising two layers, a top layer permeable for the impurities and a layer under the top layer absorbing the impurities have been disclosed. In, e.g., EP-A-146 980 a transfusing member is described consisting of a metal roller provided with a first covering of pigmented RTV silicone rubber (RTV201/200, wherein silica particles are present) and a second covering of non-pigmented silicone rubber obtained by cross-linking an α,ω-hydroxy-polymethylsiloxane with a tetra-ethyl silicate under influence of di-butyl tin dilaurate.
    In EP-A-581 365 a transfusing member is disclosed consisting of a support with a pigmented rubber layer, wherein the pigment is preferably carbon black, and a top layer of silicone rubber.
    In most of the applications of both a fusing roller and a transfusing member, a release agent, most frequently a silicone oil, is applied to the fusing or transfusing members to prevent hot-offset (i.e. toner particles adhering to the surface of the fusing or transfusing members instead of to the substrate) and to enhance the lifetime of the surface of the fusing and transfusing members.
    The use of a release agent can however create problems in the finished image, basically because it gives kind of gloss to the image and that, when the release agent is not evenly spread over the image differences in gloss appear. Thus the use of release agents frequently entails problems of streaks, oily look, patchiness, etc. in the finished image. When silicone oil is applied to a transfusing member that comes in direct contact with the photoconductor, the photoconductor can be soiled by the silicone oil and therefore it is important that the use external release agent can be minimised or preferably avoided.
    It has been proposed, for avoiding hot-offset when using a low amount of release agent, to change the properties of the toner particles, especially the type of toner resin that is used. Such toner particles have been disclosed in, e.g., EP-A-712 881 and EP-A-740 217. These measures do indeed offer the possibility of hot-pressure fixing even when using very low amounts of release agent, but because of the need to use special toner resins, the degrees of freedom in toner design, e.g., with respect to mechanical strength, chargeability, etc., are diminished.
    Therefore the need for fusing and/or transfusing members that can be used, when only small amounts of release agent is used, is still there.
    OBJECTS AND SUMMARY OF THE INVENTION
    It is an object of this invention to provide a fusing member that can be used in hot-pressure fixing of toner particles to a substrate while avoiding the use of substantial amounts of release agents on the surface of the fusing member.
    It is a further object of the invention to provide a fusing member that can be used in hot-pressure fixing of toner particles to a substrate while avoiding the use of substantial amounts of release agents on the surface of the fusing member that can be for a very long time preparing a large amount of prints before hot-offset appears.
    It is an other object of the invention to provide a method for hot-pressure fixing of toner particles wherein only small amounts of release agent are applied to the fusing roller.
    Further objects and advantages of the invention will become clear from the detailed description hereinafter.
    The objects of the invention are realised by providing a fusing member comprising a support, and on said support,
  • an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
  • a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick.
    • Preferably said second layer has silicone containing elastomer and contains at least 5 % by weight of metal oxide particles having a specific surface of ≥ 30 m2.
    The objects of the invention are further realised by providing an imaging method comprising the steps of :
    • image-wise applying toner particles to a substrate and
    • fixing said toner particles to said substrate by simultaneous application of heat and pressure,
      characterised in that :
      • said fixing proceeds in a fusing system wherein a fusing member is present comprising
      • a support, and on said support,
      • an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      • a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick and
      • that at most 320 mg/m2 of a release agent is applied to the surface of said fusing roller.
    DETAILED DESCRIPTION OF THE INVENTION
    As described above, during fusing and transfusing a release agent, most frequently a silicone oil, is applied to the fusing or transfusing members to prevent hot-offset (i.e. toner particles adhering to the surface of the members instead of to the substrate) and to enhance the lifetime of the surface of the fusing and transfusing members. In this document the wording "fusing member" will be used to indicate both a fusing member and a transfusing member. It was now found, after experimentation, that it was possible to design a member that could be used as fusing member with a very low amount of external release agent, e.g. silicone oil, or even without any external release agent and still had a long lifetime and did not show hot-offset. Therefore the fusing member, as in the prior art, comprised two layers on a support wherein an outermost layer containing at most 5 % by weight of an inorganic filler is in direct contact with a second impurity absorbing layer wherein preferably at least 5 % by weight of metal oxide particles are present.
    The outermost layer
    Contrary to the prior art fusing members, however, it was found that the outermost layer of the fusing member according to this invention, had to be quite soft. Whereas in the prior art fusing members, the outermost layer is chosen to be quite hard (e.g. a hardness equal to or larger than 40 Shore A), it was now found that fusing members having an outermost layer, being between 5 and 500 µm thick, with a degree of swelling factor equal to or higher than 3 % gave better results in terms of avoiding hot-offset than the harder prior art outermost layers. The swelling factor is in the case of an outermost layer according to this invention an indication of the softness, a layer with a high swelling factor is quite soft. It is preferred that an outermost layer in a fusing member according to this invention has a swelling factor, SF, equal to or larger than 3 , more preferably SF ≥ 5.
    The swelling factor is measured as follows : The thickness of a self-supporting sample of the outermost layer measuring about 20 mm x 3 mm is measured to an accuracy of 0.1 µm. This is the value Thd, standing for dry thickness.
    Afterwards the self-supporting sample is wetted with toluene and the sample is allowed to swell for 3 minutes, then the excess toluene is wiped and the thickness of the swollen sample is again measured to an accuracy of 0.1 µm. This is the value Thw. The swelling factor, SF, is Thw/Thd.
    Preferably at most 5 % by weight of an inorganic filler is added to the outermost layer, more preferably at most 2 % by weight of an inorganic filler is added and in an even more preferred embodiment, it no inorganic filler at all is deliberately added to the outermost layer, so that it contain no inorganic filler, except for possible impurities that can be present in the other ingredients of the layer .
    Moreover it showed very beneficial to have an outermost layer having a peeling force lower than 5 N/m measured according to the Finat No 3 norm, with Tape TESA 4163 at a peeling speed of 30 cm/min. Thus peeling force is the force necessary to peel a TESA 4163 tape away from the outermost layer at a speed of 30 cm/min.
    The outermost layer, which is preferably the outermost layer of the fusing member that comes in direct contact with the toner particles, contains preferably at least 80 % by weight of a silicone elastomer (silicone rubber) being loosely cross-linked and forming a kind of network having a low amount of cross-links. The outermost layer may further contain, imbedded in said network a silicone oil with a molecular weight equal to or larger than 50,000. A well suited silicone oil is, e.g., the silicone oil sold by ABCR GmbH, Karlsruhe, Germany under trade name DGM-000. Very well suited elastomers, for forming the outermost layer in a fusing member of this invention, are RTV or loosely cross-linked silicone elastomers formed by poly-addition of a organopolysiloxane with average molecular weight < 300,000 and/or an organopolysiloxane gum with average molecular weight > 300,000 having an alkenyl group, preferably at least two alkenyl groups, which are preferably vinyl groups. The latter silicone rubbers are preferred. Very preferred silicone rubbers for use in the outermost layer of a fusing member of this invention are silicone rubbers produced by cross-linking of organopolysiloxanes containing more than 0.005 milli-equivalent of vinyl groups per g and less than 0.1 milli-equivalent of vinyl groups per g. More preferably the content of vinyl groups in organopolysiloxanes, useful for forming the outermost layer of a fusing member of this invention, is between 0.005 and 0.05 milli-equivalent of vinyl groups per g. The equivalent value of vinyl groups is calculated by dividing the number of vinyl groups in the organopolysiloxane by the molecular weight of the organopolysiloxane.
    The outermost layer can comprise a mixture of organopolysiloxanes with free alkenyl groups. In this case the average alkenyl content of the mixture is preferably between 0.005 milli-equivalent and 0.1 milli-equivalent of vinyl groups per g. More preferably the average content of vinyl groups in such a mixture of organopolysiloxanes, is between 0.005 and 0.05 milli-equivalent of vinyl groups per g.
    The vinyl groups on the organopolysiloxane can be terminal groups or the vinyl groups can be side groups in the organopolysiloxane. Typical examples of useful organopolysiloxanes are represented by the formulas :
    Figure 00070001
    In these formulas
    R= alkyl or aryl group, preferably methyl, ethyl, 3,3,3-trifluorpropyl and phenyl.
    Organopolysiloxanes with an alkenyl group and with average molecular weight < 300,000 are commercially available, e.g., from Rhone-Poulenc under trade name SILCOLEASE 7420, SILCOLEASE 7440, from ABCR, Karlsruhe, Germany under trade name VGM-021. Organopolysiloxane guns with an alkenyl group and with average molecular weight > 300,000 commercially available, e.g., from ABCR, Karlsruhe, Germany under trade name DMS-V41, DMS-V46 and VDT-153.
    The outermost layers in a fusing member according to this invention are frequently applied from a coating solution by dip-coating or by ring-coating. When doing so it is beneficial to use a mixture of a organopolysiloxane with an alkenyl group and with average molecular weight < 300,000 and/or an organopolysiloxane gum with an alkenyl group and with average molecular weight > 300,000, since by doing so the viscosity of the coating solution can easily be adjusted for optimum coating quality without using a separate viscosity regulating compound.
    The organopolysiloxane with an alkenyl group and with average molecular weight < 300,000 and an organopolysiloxane gum with an alkenyl group and with average molecular weight > 300,000, forming the outermost layer of a fusing member according to this invention, can be hardened by reaction with an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule. When an hardener of this type is used it is added to the coating solution so that between 0.5 to 20 moles of hydrogen atoms direct bound to a Si-atom are present per mole of the alkenyl groups.
    Typical examples are :
    Figure 00080001
    When preparing the outermost layer for a fusing member according to this invention, the cross-linking reaction can be speeded up by addition of a Pt-catalyser an a concentration between 0.1 to 500 ppm with respect to the total amount of organopolysiloxanes.
    The outermost layer can comprise further additives, if so desired, e.g. cure retardants, heat stabilisers, flame retardants, plasticisers, anti-static agents, electric conductive compounds, etc.
    The second layer immediately in contact with the outermost layer
    The second layer comprises preferably at least 80 % by weight of a silicone rubber and preferably at least 5 % by weight of inorganic filler particles with specific surface of at least 30 m2/g, more preferably said particles have a specific surface of at least 50 m2/g and even more preferably said particles have a specific surface of at least 100 m2/g. This filler can be SiO2, TiO2, Al2O3, a pigment as, e.g. Cu-phthalocyanine. In a second layer of the present invention it is preferred that the inorganic filler with specific surface of at least 30 m2/g is a member selected from the group consisting of SiO2, TiO2, and Al2O3. Surprisingly, it showed that second layer carbon black as filler, did not work very well when the second layer is combined with a soft outermost layer as is the case in a fusing member of this invention. This is contrary to the disclosure of EP-A-581 365 where a second layer comprising carbon black as filler was most beneficial, when it is combined with a hard outermost layer.
    The presence of the filler aids the fusing member to absorb compounds coming from the heated toner particles and/or the heated image receiving member that soil the surface of the fusing member and that penetrate the outermost layer. Thus the surface of the fusing member stays clean for a longer time of use.
    The second layer is in a fusing member of this invention mostly used as the layer for transporting the thermal energy needed to fuse the toner particles from a source of heat towards the outermost layer. Therefore the thermal conductivity of the second layer is at least 0.4 W/m.K (measured according to DIN 52612 in Watt per meter times degree Kelvin), preferably the thermal conductivity of the second layer is at least 0.7 W/m.K . The high thermal conductivity is beneficial for cold offset, which means that when the fusing member has a second layer with high thermal conductivity the fusing process of the toner particles starts a lower temperatures. In order to control the thermal conductivity of the second layer in a fusing member according to this invention, this second layer further comprises preferably inorganic filler particles having an average volume diameter of at least 1 µm, this larger filler particles can be silica, CuO, Fe2O3, Al2O3 etc.
    The support
    The support in a fusing member of the present invention can be any support known in the art. A metal support, e.g. aluminium, stainless steel, etc., are preferred supports.
    The support can be in the form of a roller, which can be a hollow metal (e.g. Al, Stainless steel, etc.) cylinder incorporating an heating source or in the form of an endless belt.
    If so desired it is possible to include, in a fusing member of this invention, an adhesive layer between the support and the second layer.
    The fusing member of this invention can be used in a fusing device as a heated fixing roller coupled to a pressure roller for hot pressure fixing of the toner particles. In this case, the amount of filler that can incorporated in the second layer depends whether the fusing member is used as nip-forming roller or not. When, in such a fixing device, the fusing member of this invention is used as nip-forming roller, then the amount of filler is restricted by the need for having a good elasticity of the nip-forming roller. When in such a fixing device, the pressure roller is used as nip forming roller, more filler can be added to the second layer which makes it possible to have a second layer with high thermal conductivity. It is thus preferred, in a fixing device wherein a fusing member of this invention is coupled, as fixing roller, to a pressure roller for hot pressure fixing of the toner particles that the pressure roller is the nip-forming roller, so that a second layer with high thermal conductivity can be used in the fusing member. Since the fixing roller is the heated roller in the couple fixing roller/pressure roller and it is usually heated from inside the support (which is most frequently an hollow cylinder) a second layer with high thermal conductivity is beneficial for bringing the heat rapidly to the surface of the fixing roller which in turn allows for higher fixing speed.
    A fusing member of this invention can also be used as a transfusing member, in this case the toner image present on a photoconductor or on an intermediate member is not directly transferred to a final image receiving substrate and fixed there, but is first transferred to a transfusing member, from where it is further, in one step transferred and fixed to the final image receiving member. An printer using toner particles in a transfuse system is more complicated than a printer wherein direct transfer proceeds, but a transfuse system has the advantage that lower fixing temperature can be used.
    In printers with transfusing systems it is often customary to avoid direct contact between the photoconductor and the transfusing member to avoid soiling of the photoconductor, therefore a toner image, developed on the photoconductor is often first transferred to an intermediate member, e.g. a belt or roller made from non-soiling material, as metal or a polymer, and from said intermediate member to the transfuse member. A fusing member of this invention can be used as transfusing member in printers with direct contact between the photoconductor as well as in printers wherein the image is transferred from the photoconductor to the transfusing member over an intermediate non-soiling member.
    A fusing member according to this invention can be used in any imaging method using toner particles, e.g., electrophotography, direct electrostatic printing, ionography, magnetography, etc. A fusing member of this invention is particularly well suited in imaging method using dry toner particles with an average volume diameter between 2 and 20 µm.
    A fusing member of the present invention can be used with printers wherein the final image receiving substrate is in sheet form as well as in printers wherein the final image receiving substrate is in web form. A fusing member of this invention can most beneficially be used in the latter printers.
    Since a fusing member of this invention can be used both a fusing roller as well as transfusing member with very low amounts of external release agent, the invention also encompasses an imaging method comprising the steps of :
    • image-wise applying toner particles to a substrate and
    • fixing said toner particles to said substrate, by simultaneous application of heat and pressure, in a fixing device with a fusing roller coupled to a pressure roller
      characterised in that :
      • said fusing roller comprises a support, and on said support,
      • an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      • a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick
        • and
      • that at most 320 mg/m2 of a release agent is applied to the surface of said fusing roller.
        It also encompasses an imaging method comprising the steps of - bringing a toner image on a transfuse member,
      • transferring said toner image from said member to a final image receiving substrate, and fixing said image,
        characterised in that
      • said transfusing member comprises a support, and on said support,
      • an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      • a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick and
      • that at most 320 mg/m2 of a release agent is applied to the surface of said transfusing member.
    EXAMPLES
    The fusing members are used in the examples as fusing rollers, to fuse, without applying any external release agent to the surface, commercially available CHROMAPRESS (trade name of Agfa-Gevaert NV, Mortsel Belgium) toner to 4CC-ART paper of 115 g/m2 (trade name of ENSO). A fixing window was determined by taking the temperature were fusing starts (the end of ,the cold offset) and the temperature at which hot offset sets on is determined after printing 100 sheets of paper in DIN A3 format and after printing 2000 sheets of paper in DIN A3 format, normal fixing proceeded at 145 °C. The larger the value, the better, a fixing window after 2000 sheets of 15 °C is acceptable, a fixing window above 20 °C is good and a fixing window after 2000 sheets of 25 °C is very good. The printed sheets were covered for x % with toner particles.
    For examples 4, 8, 9, 10 and 11 the cold offset temperature after fixing 100 sheets is given in table 2. This temperature is a measure for the ease of fusing the toner particles, thus the lower the better.
    The fusing members were also used in an experimental transfuse set-up. An electrostatic latent image was developed on a photoconductor by commercially available CHROMAPRESS (trade name of Agfa-Gevaert NV, Mortsel Belgium) toner, the developed image was transferred from there to a transfusing member with a construction according to this invention, and then further transferred to plain paper 4CC-ART paper of 115 g/m2 (trade name of ENSO). The transfusing member was heated and was used without any external release agent applied to its surface. A fixing window was determined by taking the temperature were fusing starts (the end of the cold offset) and the temperature at which hot offset sets on is determined after printing 100 sheets of paper in DIN A3 format and after printing 7200 sheets of paper in DIN A3 format, normal transfusing took place at 120 °C. The larger the value, the better a fixing window after 7200 sheets of 10 °C is acceptable, a fixing window after 7200 sheets of 15 °C is good and a fixing window after 7200 sheets of 20 °C is very good.
    The results are given in table 1.
    The peel force in N/m was also determined according to Finat No 3, with Tape TESA 4163 at a peeling speed of 30 cm/min.
    The SECOND LAYER closest to the support
    In comparative examples 1 to 2 and invention examples 1 to 6, the same second layer (closest to the support) was used. It was prepared by mixing 150 g of SLE5900 (trade name of general Electric, USA for a silicone rubber containing fine silica particles having specific surface > 30 m2/g) part A and 150 g of SLE5900 part B are with 75 g of iso-octane 100. The solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 70 µm thick. The thermal conductivity of this second layer was 0.18 W/m.K.
    COMPARATIVE EXAMPLE 1 (CE1)
    100 g of DMS-V22, trade name of ABCR, Karlsruhe, Germany, having a vinyl content of 0.21 milli-equivalent per g (meq/g) and a formula
    Figure 00140001
    were mixed with
    5.4 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00140002
    and with 0.43 g of a solution containing 2.27 % of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.90 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 2.3. This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 55 µm.
    COMPARATIVE EXAMPLE 2 (CE2)
    80 g of DMS-V25, trade name of ABCR Karlsruhe, Germany, having a vinyl content of 0.11 milli-equivalent per g (meq/g) and a formula
    Figure 00150001
    were mixed with
    4.3 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00150002
    and with 0.33 g of a solution containing 2.27 % of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.70 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 2.6 . This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 35 µm.
    EXAMPLE 1 (E1)
    100g of DMS-V31, trade name of ABCR Karlsruhe, Germany ????, having a vinyl content of 0.07 milli-eqiuivalent per g (meq/g) with formula
    Figure 00160001
    were mixed with
    3.4 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00160002
    and with 0.42 g of a solution containing 2.27 of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.88 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 3.2 This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 35 µm.
    EXAMPLE 2 (E2)
    40g of DMS-V52, trade name of ABCR, Karlsruhe, Germany, having a vinyl content of 0.013 milli-equivalent per g (meq/g) with formula
    Figure 00160003
    were mixed with 40 g iso-octane 100 and
    0.254 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00170001
    and with 0.16 g of a solution containing 2.27 of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.34 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 4.6. This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 50 µm.
    EXAMPLE 3 (E3)
    60g of DMS-V41, trade name of ABCR, Karlsruhe, Germany, having a vinyl content of 0.03 milli-eguivalent per g (meq/g) with formula
    Figure 00170002
    were mixed with 20 g iso-octane 100 and
    0.88 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00170003
    and with 0.25 g of a solution containing 2.27 of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.52 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 5.4. This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 35 µm.
    EXAMPLE 4 (E4)
    20g of VGM-021, trade name of ABCR Karlsruhe, Germany, having a vinyl content of 0.034 milli-equivalent per g (meq/g) with formula
    Figure 00180001
    were mixed with 80 g iso-octane 100 and
    0.076 g of SILCOLEASE CROSSLINKER 91A, trade name of Rhodia, France for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00180002
    To this mixture 0.21 g of SILCOLEASE CATALYST 90B was added. With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 5.4 . This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 25 µm.
    EXAMPLE 5 (E5)
    45 g of DMS-V46, trade name of ABCR, Karlsruhe, Germany, having a vinyl content of 0.018 milli-equivalent per g (meq/g) with formula
    Figure 00190001
    were mixed with 35 g iso-octane 100 and
    0.39 g of SILOPREN U VERNETZER 830, trade name of Bayer AG, Leverkusen, Germany, for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00190002
    and with 0.18 g of a solution containing 2.27 of 1-ethynyl-1-cyclohexanol in iso-octane 100. To this mixture, 0.39 g of a solution, in 129 g of iso-octane 100, of 1 g SILOPREN U KATA PTS, trade name of Bayer AG, Leverkusen, Germany, for a complex of Pt-siloxane in 2-propanol, were added as catalyser.
    With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 5.5 . This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 35 µm.
    EXAMPLE 6
    10g of VGM-021, trade name of ABCR, Karlsruhe, Germany, having a vinyl content of 0.034 milli-equivalent per g (meq/g) with formula
    Figure 00190003
    were mixed with 47 g iso-octane 100. To this mixture 3.33 g of DGM-000, trade name of ABCR for a high molecular weight silicone oil with formula
    Figure 00200001
    and
    0.23 g of SILCOLEASE CROSSLINKER 91A, trade name of ??????? for an organopolysiloxane containing at least two hydrogen atoms direct bound to a Si-atom per molecule with formula
    Figure 00200002
    To this mixture 0.633 g of SILCOLEASE CATALYST 90B was added. With this solution a self-supporting layer was prepared and the swelling factor, SF, was determined as described above and was 11 . This solution was also coated on the second layer as described above with a ring- coater at 1.25 mm/s and reacted for 20 minutes at 165 °C. This gave an uppermost layer with thickness of 35 µm.
    EXAMPLE 7 (E7)
    Example 4 was repeated except for the second layer. The second layer was prepared by mixing 60 g of SILCOSEAL RTV 201 containing silica having specific surface > 30 m2/g, (trace name of General Electric) and 20 g cyclohexane. 6 g of VERNETZER A21 (trade name of Rhodia) was further added to the solution. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 60 minutes at 100 °C. This gave a second layer being 100 µm thick. The thermal conductivity of this second layer was 0.18 W/m.K.
    EXAMPLE 8 (E8)
    Example 4 was repeated except for the second layer. The second layer was prepared by mixing 100 g of TSE-3331A and 100 g of TSE-3331B containing carbon particles with, (trade names of General Electric). This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 60 minutes at 100 °C. This gave a second layer being 250 µm thick. The thermal conductivity of this second layer was 0.63 W/m.K.
    Example SF meq/g peel W100F W2000F W100T W7200T
    CE1 2.3 0.21 1.40 45 5 30 2
    CE2 2.6 0.11 1.89 45 7 34 5
    E1 3.2 0.07 1.31 40 15
    E2 4.6 0.013 1.38 40 22 32 17
    E3 5.4 0.03 1.88 47 25 35 19
    E4 5.4 0.03 1.52 40 30 34 15
    E5 5.5 0.018 1.49 45 30 30 23
    E6 11 0.025 ? 45 25 32 11
    E7* 5.4 0.034 1.57 40 17 34 13
    E8* 5.4 0.034 1.58 45 5 30 11
    SF : Swelling factor
    meq/g : milli-equivalent vinyl groups in the organonolysiloxane
    peel : peel force in N/m according to Finat No 3, with Tape TESA 4163 at a peeling speed of 30 cm/min
    W100F in °C: fixing window after 100 sheets with fusing member used in a fixing device
    W2000F in °C: fixing window after 2000 sheets with fusing member used in a fixing device
    W100F in °C: fixing window after 100 sheets with fusing member used in a transfusing device
    W7200T in °C: fixing window after 7200 sheets with fusing member used in a transfusing device
    E7 and E8 : outermost layer the same as in example 4 (E4) but with different second layer.
    It is clear that the fixing window are better when the top layer has a higher swelling factor. When the second layer comprises silica as filler (E1-E7), the fixing windows are wider than when carbon particles are used as filler in the second layer (E8).
    The thermal conductivity of the second layer is quite important for allowing rapid fixing at fairly low temperatures, as indicated by the following examples.
    EXAMPLE 9 (E9)
    Example 4 was repeated except for the second layer. The second layer was prepared by mixing 90 g of TSE-389 containing fine silica particles having specific surface > 30 m2/g, (trade name of General Electric) and 10 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 100 µm thick. The thermal conductivity of this second layer was 0.18 W/m.K.
    EXAMPLE 10 (E10)
    Example 4 was repeated except for the second layer. The second layer was prepared by mixing 40 g of TSE-326 containing a metal oxide having a diameter larger than 1 µm, (trade name of General Electric) and 10 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 50 µm thick. The thermal conductivity of this second layer was 0.43 W/m.K.
    EXAMPLE 11 (E11)
    Example 4 was repeated except for the second layer. The second layer was prepared by mixing 142.5 g of TSE-3280G containing a metal oxide having a diameter larger than 1 µm, (trade name of General Electric) and 7.5 g cyclohexane. This solution was coated with a ring coater at a coating speed of 0.75 mm/s on the degreased surface of an aluminium cylinder with diameter 140 mm. The coating is hardened for 15 minutes at 165 °C. This gave a second layer being 50 µm thick. The thermal conductivity of this second layer was 0.88 W/m.K.
    In table 2 the results regarding cold-offset and fixing window obtained with fusing member with different fillers are given. Example 4 and example 8 are repeated in this table.
    Example Thermal conduc W/m.K Cold offset 100 W2000F
    E4 0.18 138 °C 30 °C
    E9 0.18 135 °C 30 °C
    E10 0.43 125 °C 17 °C
    E8 0.63 130 °C 5 °C
    E11 0.88 125 °C 18 °C
    It is clear that the ease of fusing, measured by a lower cold offset temperature, becomes better as the thermal conductivity of the second layer becomes higher with an acceptable to good fixing window. Surprisingly, a fusing member wherein the second layer is filled with carbon (E8) did, although it showed a relatively high thermal conductivity, not show as low a cold offset temperature as E10 and E11, wherein the second layer contained oxides with diameter higher than 1 µm and did certainly not show an acceptable fixing window.

    Claims (14)

    1. A fusing member comprising a support, and on said support,
      an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick.
    2. A fusing member according to claim 1, wherein said second layer contains a silicone containing elastomer and at least 5 by weight of metal oxide particles having a specific surface of ≥ 30 m2.
    3. A fusing member according to claim 2, wherein said metal oxide particles are a member selected from the group consisting of SiO2, TiO2 and Al2O3.
    4. A fusing member according to any of claims 1 to 3, wherein said outermost layer has a peel force, measured being according to Finat No 3, with Tape TESA 4163 at a peeling speed of 30 cm/min equal to or lower than 5 N/m.
    5. A fusing member according to any of claims 1 to 4 wherein, silicone elastomer in said outermost layer is based on an organopolysiloxane with free alkenyl groups and a alkenyl content between 0.005 milli-equivalent/g and 0.1 milli-equivalent/g, both limits included.
    6. A fusing member according to any of claims 1 to 4 wherein, silicone elastomer in said outermost layer is based on a mixture of organopolysiloxanes with free alkenyl groups and wherein said mixture has an average alkenyl content between 0.005 milli-equivalent/g and 0.1 milli-equivalent/g, both limits included.
    7. A fusing member according to claim 5 or 6 , wherein said alkenyl groups are vinyl groups.
    8. A fusing member according to claim 7, wherein said organopolysiloxane is a member selected from the group consisting of
      Figure 00250001
      Wherein , R = alkyl or aryl group, preferably methyl, ethyl, 3,3,3-trifluorpropyl and phenyl.
    9. A fusing member according to any of claims 1 to 5, wherein said outermost layer further comprises an organopolysiloxane containing, per molecule, at least two hydrogen atoms directly bound to a Si-atom.
    10. A fusing member according to claim 6, wherein said outermost layer further comprises in the bulk a silicone oil with weight average molecular weight ≥ 50,000.
    11. A fusing member according to anyone of the preceding claims, wherein said second layer has a thermal conductivity ≥ 0.4 W/m.K.
    12. A fusing member according to anyone of the preceding claims, wherein said second layer further comprises an inorganic filler with an weight average diameter between 1 µm.
    13. An imaging method comprising the steps of :
      image-wise applying toner particles to a substrate and
      fixing said toner particles to said substrate, by simultaneous application of heat and pressure, in a fixing device with a fusing roller coupled to a pressure roller
      characterised in that :
      said fusing roller comprises a support, and on said support,
      an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick and
      that at most 320 mg/m2 of a release agent is applied to the surface of said fusing roller.
    14. An imaging method comprising the steps of
      bringing a toner image on a transfuse member,
      transferring said toner image from said member to a final image receiving substrate, and fixing said image,
      characterised in that
      said transfusing member comprises a support, and on said support,
      an outermost layer containing a silicone elastomer, with at most 5 % by weight of filler particles, said elastomer layer having a swelling factor, SF, equal to or higher than 3 and a thickness between 5 and 500 µm, both limits included and
      a second layer with an impurity absorbing material, closer to said support and immediately in contact with said outermost layer, said second layer being at least 40 µm thick and
      that at most 320 mg/m2 of a release agent is applied to the surface of said transfusing member.
    EP98204368A 1998-12-21 1998-12-21 A fusing member for hot pressure fixing of toner particles and for transfusing toner particles Withdrawn EP1014220A1 (en)

    Priority Applications (2)

    Application Number Priority Date Filing Date Title
    EP98204368A EP1014220A1 (en) 1998-12-21 1998-12-21 A fusing member for hot pressure fixing of toner particles and for transfusing toner particles
    US09/461,368 US6365279B1 (en) 1998-12-21 1999-12-15 Fusing member for hot pressure fixing of toner particles and for transfusing toner particles

    Applications Claiming Priority (1)

    Application Number Priority Date Filing Date Title
    EP98204368A EP1014220A1 (en) 1998-12-21 1998-12-21 A fusing member for hot pressure fixing of toner particles and for transfusing toner particles

    Publications (1)

    Publication Number Publication Date
    EP1014220A1 true EP1014220A1 (en) 2000-06-28

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    Application Number Title Priority Date Filing Date
    EP98204368A Withdrawn EP1014220A1 (en) 1998-12-21 1998-12-21 A fusing member for hot pressure fixing of toner particles and for transfusing toner particles

    Country Status (1)

    Country Link
    EP (1) EP1014220A1 (en)

    Cited By (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    EP1197810A2 (en) * 2000-10-13 2002-04-17 Xeikon Nv A fixing device and method for transfusing toner
    EP1284186A3 (en) * 2001-08-06 2003-05-21 Konica Corporation Fixing belt, fixing roller, production method thereof, fixing apparatus and image fixing method utilizing the apparatus
    EP1336504A3 (en) * 2002-02-13 2005-12-07 Konica Corporation Fixing belt, fixing roller, production method thereof, fixing apparatus and image fixing method utilizing the apparatus
    CN103889077A (en) * 2012-12-21 2014-06-25 富士施乐株式会社 Method For Manufacturing Sheet Heating Element, Fixing Device, And Image Forming Apparatus

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    Publication number Priority date Publication date Assignee Title
    US4372246A (en) * 1981-05-04 1983-02-08 Xerox Corporation Externally heated fusing member for electrostatographic copiers
    JPS59209129A (en) * 1983-05-12 1984-11-27 Kinyoushiya:Kk Fixing roll
    JPS6068930A (en) * 1983-09-26 1985-04-19 Kiyoshi Sugiyama Manufacture of fixing rubber roll for dry type electrostatic transfer copying machine
    EP0531011A1 (en) * 1991-09-05 1993-03-10 Xerox Corporation Multilayered fuser member

    Patent Citations (4)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US4372246A (en) * 1981-05-04 1983-02-08 Xerox Corporation Externally heated fusing member for electrostatographic copiers
    JPS59209129A (en) * 1983-05-12 1984-11-27 Kinyoushiya:Kk Fixing roll
    JPS6068930A (en) * 1983-09-26 1985-04-19 Kiyoshi Sugiyama Manufacture of fixing rubber roll for dry type electrostatic transfer copying machine
    EP0531011A1 (en) * 1991-09-05 1993-03-10 Xerox Corporation Multilayered fuser member

    Non-Patent Citations (2)

    * Cited by examiner, † Cited by third party
    Title
    PATENT ABSTRACTS OF JAPAN vol. 009, no. 080 (M - 370) 10 April 1985 (1985-04-10) *
    PATENT ABSTRACTS OF JAPAN vol. 009, no. 209 (M - 407) 27 August 1985 (1985-08-27) *

    Cited By (7)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    EP1197810A2 (en) * 2000-10-13 2002-04-17 Xeikon Nv A fixing device and method for transfusing toner
    US6650860B2 (en) 2000-10-13 2003-11-18 Xeikon International N.V. Fixing device and method for transfusing toner
    EP1197810A3 (en) * 2000-10-13 2004-10-20 Xeikon International N.V. A fixing device and method for transfusing toner
    EP1284186A3 (en) * 2001-08-06 2003-05-21 Konica Corporation Fixing belt, fixing roller, production method thereof, fixing apparatus and image fixing method utilizing the apparatus
    US6902266B2 (en) 2001-08-06 2005-06-07 Konica Corporation Fixing belt, fixing roller, production method thereof, fixing apparatus and image fixing method utilizing the apparatus
    EP1336504A3 (en) * 2002-02-13 2005-12-07 Konica Corporation Fixing belt, fixing roller, production method thereof, fixing apparatus and image fixing method utilizing the apparatus
    CN103889077A (en) * 2012-12-21 2014-06-25 富士施乐株式会社 Method For Manufacturing Sheet Heating Element, Fixing Device, And Image Forming Apparatus

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