FIELD OF THE INVENTION
[0001] 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
[0002] 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".
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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
[0012] 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.
[0013] 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.
[0014] 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.
[0015] Further objects and advantages of the invention will become clear from the detailed
description hereinafter.
[0016] 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 m
2.
[0017] 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
[0018] 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
[0019] 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 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 µm. This is the value Th
w. The swelling factor, SF, is Th
w/Th
d.
[0020] 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 .
[0021] 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.
[0022] 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 :
In these formulas
R= alkyl or aryl group, preferably methyl, ethyl, 3,3,3-trifluorpropyl and phenyl.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] Typical examples are :
[0027] 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.
[0028] 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
[0029] 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
2O
3, 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 m
2/g is a member selected from the group consisting of SiO
2, TiO
2, and Al
2O
3. 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.
[0030] 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.
[0031] 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, Fe
2O
3, Al
2O
3 etc.
The support
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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
[0040] 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.
[0041] 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
[0042] 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)
[0043] 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
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
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.
[0044] 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)
[0045] 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
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
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)
[0046] 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
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
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)
[0047] 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
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
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)
[0048] 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
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
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)
[0049] 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
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
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)
[0050] 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
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
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
[0051] 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
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
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
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)
[0052] 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)
[0053] 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.
Table 1
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). |
[0054] 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)
[0055] 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)
[0056] 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)
[0057] 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.
[0058] 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.
Table 2
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 |
[0059] 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.
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
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.