Wick for dispensing fuser oil

An improved fluid applicating wick for use in applying release fluids to a fuser member surface of a fusing system for fusing toner images is described. The wick comprises a working surface material which contacts the fuser member surface, and a backing material to which the working surface material is needled. A preferred fluid applicating wick comprises a layer of Teflon felt or fiber as a working surface material is needled to a fibrous or felted Nomex material.

BACKGROUND OF THE INVENTION 
This invention relates generally to fusing systems utilized for pressure 
fixing toners at elevated temperatures in electrostatic copying devices 
and more particularly to an improved wick member for applying release 
fluid to fuser members in such fusing systems. 
In the process of xerography a light image of an original to be copied is 
typically recorded in the form of a latent electrostatic image upon a 
photosensitive member with subsequent rendering of the latent image 
visible by the application of electroscopic particles, commonly referred 
to as toner. The visual toner image can be fixed directly upon the 
photosensitive member or transferred from the member to another support, 
such as a sheet of plain paper, with subsequent affixing of the image 
thereto. Toners are well known in the art and may be of various types. 
In order to affix or fuse electroscopic toner material onto a support 
surface permanently by heat, it is necessary to elevate the temperature of 
the toner material to a point at which the constituents of the toner 
material coalesce and become tacky. This action causes the toner to flow 
to some extent into the fibers or pores of support members of otherwise 
upon the surface thereof. Thereafter, as the toner material cools, 
solidification of the toner material occurs causing the toner material to 
be bonded firmly to the support member. In both the xerographic as well as 
the electrographic recording arts, the use of thermal energy for fixing 
toner images onto a support member is old and well known. 
Several approaches to thermal fusing of electroscopic toner images onto a 
support have been described in the prior art and include providing the 
concomitant application of heat and pressure as by a roll pair maintained 
in pressure contact, a flat or curved plate member in pressure contact 
with a roll, a belt member in pressure contact with a roll, and the like. 
Heat may be applied by heating one or both of the rolls, plate members or 
belt members. The fusing of the toner takes place when the proper 
combination of heat, pressure and contact time are provided, the balancing 
of these parameters being well known in the art and varying according to 
various factors which must be independently determined for each particular 
situation. 
During operation of a fusing system of the type where there is a thermal 
fusing of electroscopic toner images onto a support in which at least one 
fuser member, such as a roll, plate or belt, is heated, the support member 
to which the toner images are electrostatically adhered, is moved through 
the nip formed between the members with the toner image pressure 
contacting the fuser roll thereby to effect heating of the toner images 
within the nip. By controlling the heat transfer to the toner, virtually 
no offset of the toner particles from the copy sheet to the fuser member 
is experienced under normal conditions. This is because the heat applied 
to the surface of the fuser member is insufficient to raise the 
temperature of the surface of the member above the "hot offset" 
temperature of the toner at which temperature the toner particles in the 
image areas of the toner liquify and cause a splitting in the molten toner 
resulting in "hot offset". Splitting occurs when the cohesive forces 
holding the viscous toner mass together is less than the adhesive forces 
tending to offset it to a contacting surface such as a fuser roll, fuser 
belt, or fuser plate. 
Occasionally, however, toner particles will be offset to the fuser roll by 
an insufficient application of heat to the surface thereof (i.e. "cold 
offsetting"); by imperfection in the properties of the surface of the 
roll; by the toner particles insufficiently adhering to the copy sheet; by 
the electrostatic forces which normally hold them there; or by the 
reactivity of the toner material itself in those cases where the toner is 
of a reactive nature. In such a case, toner particles may be transferred 
to the surface of the fuser member with subsequent transfer to the backup 
member which provides pressure contact, during periods of time when no 
copy paper is in the nip. 
One arrangement for minimizing the foregoing problems, particularly that 
which is commonly referred to as "offsetting", has been to provide a fuser 
member with an outer surface or covering of polytetrafluoroethylene, known 
by the tradename Teflon, to which a release agent such as silicone oil, is 
applied. More recently, bare metal fuser members have been introduced for 
fusing or fixing the electroscopic toner materials to various surfaces. 
Various fluid polymer release materials which oxidize or which contain 
functional groups, can be utilized to prevent "offsetting". Exemplary of 
such systems are the disclosures in U.S. Pat. No. 3,937,637 and U.S. Pat. 
No. 3,918,804. Other release agents for bare metal fuser rolls are 
described in Belgium Pat. No. 831,662. 
In the foregoing exemplary fusing systems the release agent or release 
fluid may be applied to the fuser member by means of a wick as described 
in U.S. Pat. No. 3,718,116, U.S. Pat. No. 3,831,553 and U.S. Pat. No. 
3,841,827. The wick is generally used to dispense silicone oil, functional 
siloxane fluids, mineral oil, and many other release fluids upon the 
external surface to the fuser member in the form of a pad overlying and in 
contact with the fuser member which is heated during operation. 
As described in the foregoing patents, the wick assembly generally includes 
two different layers. A first layer in contact with the surface of the 
fuser member meters precise amounts of release fluid thereon, while a 
second layer in contact with the first layer has high release fluid 
retention capabilities for supplying the first layer with the fluid. In a 
preferred embodiment, the wick comprises a layer of Teflon which contacts 
the surface of a fuser roll, and a second layer of Nomex which has its 
underside in contact with an applicator roll, the release fluid in a sump 
or some other fluid supply device or means. Teflon and Nomex are 
trademarks of E. I. du Pont de Nemours & Company of Wilmington, Delaware. 
The prior art wick assemblies comprising two layers, such as Teflon and 
Nomex, are joined by stitching, clamping or cementing the layers together. 
These methods of fabricating the two layers have many disadvantages. 
First, these conventional wicks are relatively inefficient in transporting 
fluid, and there is relatively short wick like due to separation of 
significant portions of the two layers. Secondly, because of the tendency 
for layers of the prior art wicks to separate from each other, and because 
there is only surface to surface contact of the two layers with each 
other, there is low fluid transfer or through put from one layer to the 
other layer. 
In the prior art methods of fabricating wick materials, there is also a 
tendency for the fibers in the layers to be loosely held, thereby causing 
accumulations of fuzz(lint) and/or fibers in various machine parts. These 
can cause serious problems in copy quality, especially when the fibers 
accumulate in critical such as in metering areas resulting in non-uniform 
metering and oil streaks on copies. Toner build-up on these fibers is 
transferred back to subsequent copies as toner offset. In fact, the second 
layer is frequently flame treated prior to use in a fuser assembly to burn 
all loose fibers. 
OBJECTS OF THE INVENTION 
Accordingly it is the principal object of this invention to overcome the 
foregoing deficiencies in wicks made up of at least two layers of 
material. 
Another object of this invention is to provide an improved release fluid 
wick applicator assembly for fusing systems in xerographic copying 
machines. 
Still another object of this invention is to provide a multiple-layered 
wick material having an improved life. 
Another object of this invention is to provide a multiple-layered wick 
material capable of high fluid through-put from layer to layer. 
Another object of this invention is to provide a multiple-layered wick 
material having a reduced amount of loose fibrous material. 
SUMMARY OF THE INVENTION 
These and other objects of the instant invention are generally accomplished 
by a wick material having two or more layers, at least some of the 
material of at least one of the layers extending into the material of at 
least one of the layers. These improved composite wicks are useful for 
applying release fluid to the surface of a fuser member. 
The release fluid applicators of the present invention comprise a working 
surface layer of a first material which contacts a fuser member surface 
and a fluid retention layer of a second material which contacts the 
working surface layer, at least some of the material of at least one of 
the layers extending into the material of the other layer, the first and 
second materials being different compositions. 
The composite wicking material of the present invention comprising a first 
release fluid metering layer (the working surface) which contacts the 
fuser member surface, and a second release fluid retention layer adjacent 
the first layer and in contact therewith, constitutes a substantial 
improvement over the prior art wicking composites used in fuser 
assemblies, when at least some of the material of at least one of the 
layers extends into the material of the other layer. When a composite wick 
material was made in this manner, it was unexpectedly found that 
substantially higher release fluid through-put and uniform spreading of 
the release fluid on the fuser member was accomplished without sacrificing 
the functional or useful life of the composite wick material. In fact, it 
was discovered that the functional or useful life of the wick actually 
increased. 
Exemplary of the method of extending some of the material of at least one 
of the layers into the material of the other layer is described in U.S. 
Pat. Nos. 2,840,831 and 3,090,099. 
As used herein, working surface is defined as that surface or layer of the 
wick composite which contacts the fuser member surface. 
Further objects of this invention together with additional features and 
advantages thereof will become apparent from the following detailed 
description of the preferred embodiments of the invention read in 
conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The fuser embodiments of the present invention may be used in automatic 
xerographic reproducing machine which utilize a fuser member to which a 
release fluid is applied, for example, such as the automatic machines 
described in U.S. Pat. Nos. 3,718,116, 3,799,401 and 3,937,637 said 
patents being incorporated herein by reference. Therein are illustrated 
reproducing machines which employ an image recording drum-like or 
belt-like member, the outer periphery of which is coated with a suitable 
photoconductive material. The imaging member, either a photoconductive 
drum or belt is suitably mounted for advancing within a machine frame by 
means of a shaft which rotates or by means of a series of support shafts 
respectively, to bring the image retaining surface thereon past a 
plurality of xerographic processing stations. Suitable drive means are 
provided to power and coordinate the motion of the various cooperating 
machine components whereby a faithful reproduction of the original input 
scene information is recorded upon a sheet of final support material such 
as paper or the like. 
Since the practice of xerography is well known in the art, the various 
processing stations for producing a copy of an original are represented as 
stations A to E. Initially, the imaging member moves the photoconductive 
surface through a charging station A. At charging station A an 
electrostatic charge is placed uniformly over the photoconductive surface 
of the imaging member preparatory to imaging. The charging may be provided 
by a corona generating device of a type described in U.S. Pat. No. 
2,836,725 issued to Vyverberg in 1958. 
Thereafter, the imaging member is advanced to exposure station B where the 
charged photoconductive surface is exposed to a light image of the 
original input scene information, whereby the charge is selectively 
dissipated in the light exposed regions to record the original input scene 
in the form of a latent electrostatic image. A suitable exposure system 
may be provided by one skilled in the art. 
After exposure the photoconductive imaging member advances the 
electrostatic latent image recorded on the photoconductive surface to 
development station C, wherein a conventional developer mix is applied to 
the photoconductive surface rendering the latent image visible. A suitable 
development station may include a magnetic brush development system 
utilizing a magnetizable developer mix having carrier granules and toner 
comprising electrophotographic resin plus colorant from dyes or pigments. 
A developer mix is continually brought through a directional flux field to 
form a brush thereof. The electrostatic latent image recorded on the 
photoconductive surface is developed by bringing the brush of developer 
mix into contact therewith. The developed image on the photoconductive 
surface is then brought into contact with a sheet of final support 
material within a transfer station D and the toner image is transferred 
from the photoconductive surface to the contacting side of a final support 
sheet. The final support material may be plain paper, gummed labels, 
transparencies such as polycarbonate, polysulfone and Mylar, etc., as 
desired. 
After the toner image has been transferred to the sheet of final support 
material, the sheet with the toner image thereon is advanced to a suitable 
fuser assembly which fuses the transfer powder image thereto. After the 
fusing process, the final support material is advanced by a series of 
rolls to a copy paper tray for subsequent removal therefrom by a machine 
operator. 
Although most of the toner powder is transferred to the final support 
material, some residual toner remains on the photoconductive surface after 
the transfer of the toner powder image to the final support material. The 
residual toner particles remaining on the photoconductive surface after 
the transfer operation are removed from the imaging member as it moves 
through cleaning station E. Here the residual toner particles may first be 
brought under the influence of a cleaning corona generating device adapted 
to neutralize the electrostatic charge remaining on the toner particles. 
The neutralized toner particles are then mechanically cleaned from the 
photoconductive surface by conventional means as for example, the use of a 
resiliently based knife blade. Other cleaning modes may be used at 
cleaning station E as desired by one skilled in the art. 
It is believed that the foregoing description is sufficient for purposes of 
present application to illustrate the general operation of an automatic 
xerographic copier which can embody the teachings of the present 
invention. 
Fuser assemblies as used herein include cylindrical rolls, flat plates, 
curved plated, belts and the like. The fuser surface may be coated with 
various elastomers, or it may be a bare metal surface. For ease of 
description and applicable to all fuser members, emphasis herein is 
directed to a fuser assembly having a roll structure as a fuser member. 
The method of providing the necessary heat is not critical in the use of 
the improved composite wicking material of this invention, and the fuser 
members can be heated by internal means, external means, or both, all 
heating means being well known in the art for providing sufficient heat to 
fuse toner to its substrate. 
Referring to FIG. 1, there is shown an exemplary environment for the 
needled composite fuser wick of the present invention. The heated pressure 
fuser assembly includes a heated fuser roll 16 and a backup pressure roll 
18. Fuser roll 16 is a hollow circular cylinder with a metallic core 20 
and a Teflon layer 22. A lamp 24 serves as a source of thermal energy and 
is located at the center of the fuser roll. Power to the lamp is 
controlled by a thermal sensor generally called a thermistor contacting 
the periphery of the fuser roll as described for example in U.S. Pat. No. 
3,357,249. The backup roll 18 is also a circular cylinder and is made up 
of a metal core 30 surrounded by a thick rubber layer 32 and also a Teflon 
layer 34 to prevent soaking silicone oil into rubber layer 32 and 
subsequent swelling. 
As a sheet of material 40 is advanced between the rolls 16 and 18 the toner 
image 42 on the support material will contact the peripheral heated 
surface of the roll 16 whereby the toner image becomes tackified and in 
this tackified condition the toner will tend to offset on this roll except 
that it is partially prevented from doing so by the Teflon coating on the 
roll. It is by the lubricating wick assembly 48 which is used to apply a 
thin film of offsetting preventing liquid such as silicone oil to the 
Teflon surface 22 of the fuser roll 16 that offset is prevented. 
An oil applicator apparatus 45 includes lubricating wick assembly 48, an 
oil pan 50 for maintaining a supply of silicone oil 51 and an applicator 
roll 52. Other details relating to this embodiment may be found in U.S. 
Pat. No. 3,831,553. 
In FIG. 1, applicator roll 52 is used to convey a thin film of oil to the 
bottom face 55 of lubricating wick assembly 48 as the applicator roll is 
rotated in the direction shown by the arrow. Desirably, applicator roll 52 
is driven by an oil dispenser motor 58 which is energized during the 
fusing operation depending upon the number of copies being produced. In 
accordance with the present invention lubricating wick assembly 48 
includes two different layers, a working surface layer of a first material 
62 and a fluid retention layer of a second material 64 wherein at least 
some of the material of at least one of the layers extends into the 
material of the other layer. Strands or filaments indicated by numeral 10 
represent the material of at least one layer extending into the material 
of the other layer. In a preferred embodiment, layer 62 is fibrous Teflon 
(polytetrafluoroethylene) and layer 64 is fibrous Nomex (a heat resistant 
nylon which is the copolymer of meta-phenylenediamine and isophthaloyl 
chloride), layer 62 being needled into 64 and represented by filaments or 
strands 10. Teflon and Nomex are trademarks of Du Pont Corporation, 
Wilmington, Delaware. 
Layer 62 contacts the surface of fuser roll 16 and the underside of layer 
64 contacts applicator roll 52. Layers 62 and 64 are assembled in 
overlapping relationship and their ends are clamped between plates 66 and 
68 which are secured by any suitable means such as screws. Teflon is 
preferred as the upper layer because it has low coefficient of friction, 
low wear properties, low tendency to accumulate molten toner as well as 
thermal stability at elevated temperatures ranging up to 400.degree. F. 
and above. Nomex is preferred as a lower layer because of thermal 
stability at elevated temperatures up to 400.degree. F. and above and due 
to its high oil retention characteristics. 
In FIG. 1, there is shown an auxiliary wick 75 which may be made out of any 
suitable wicking material and which supplies oil to wick assembly 48 
through a sponge member. Auxiliary wick 75 is maintained in position by 
support member 77 and holding member 80. Details of this optional 
auxiliary wick are described in U.S. Pat. No. 3,831,553. Although it is 
not shown a metering blade may be used on the fuser member for uniformity 
of the release fluid layer. 
Referring to FIG. 2, there is shown another exemplary fuser assembly 
environment for the needled composite fuser wick material of the present 
invention. Fuser roll 1 is supplied with release fluid from lubricator 30. 
Back-up roll 2 is in pressure contact with fuser roll 1 and forms a nip 
therewith through which the substrate carrying a toner image passes and 
becomes permanently affixed to the substrate by the heated fuser roll (not 
shown). Details of lubricator 30 and its operation are disclosed in U.S. 
Pat. No. 3,799,401. Lubricator 30 includes a supply reservoir 6 which 
contains a main supply of the lubricant which is to be applied to the 
fuser assembly. Lubricator 30 includes a dispensing reservoir 26 which is 
adapted to contain a predetermined volume 28 of release agent. A 
dispensing roller 7 is mounted on a shaft for rotation about a horizontal 
axis, and is partially immersed in the predetermined volume 28 of release 
agent. As the dispensing roller 7 rotates, a film of release agents 
adheres thereto and is conveyed to wick 3, the latter being biased against 
the dispensing roller by the weight of a curved plate 4. Plate 4 is 
mounted to a cover 29 by means of a hinge 8 so that the plate can be 
lifted when it is desired to remove the wick 3. In accordance with the 
present invention, wick 3 includes two different layers, a working surface 
layer of a first material and a fluid retention layer of a second material 
wherein at least some of the material of at least one of the layers 
extends into the material of the other layer. A magnified portion of the 
preferred wick material is shown in FIG. 3 and is described below. The 
wick 3 transmits the release agent from the dispensing roller 7 and 
applies to it a heated fuser roller 1 in the fuser assembly. This fuser 
roller is the one which contacts the powder image on the sheet of paper. 
To assure that the wick 3 maintains contact with the fuser roller 1, a 
wick support plate 5 biases the wick against the fuser roller. When it is 
desired to remove the wick 3, the support plate 5 is released and moved in 
the direction of the arrow. 
To convey release agent from the supply reservoir 22 to the dispensing 
reservoir 26, an annular conveying member 44 is mounted within the supply 
reservoir. The conveying member 44 is comprised of a belt which is affixed 
by a suitable adhesive to an annular ring having teeth formed therein. The 
belt may be polyurethane or other suitable absorbent material. The details 
of conveying the release agent 9 to dispensing reservoir 26 are described 
in detail in U.S. Pat. No. 3,799,401. 
Referring to FIG. 3, there is shown a fragmented view of a portion of a 
preferred composite wicking material having the characteristics of the 
present invention. The composite wick comprises a first material or layer 
62 having a surface whih contacts the fuser member surface, and a second 
material or layer 64 one surface of which contacts the surface of layer 62 
opposite that surface of layer 62 which contacts the fuser member surface 
and the other surface of which contacts the release agent or fluid supply 
means such as an applicator roll, a spray of release fluid, a reservoir of 
release fluid, and the like. In the present invention, at least some of 
the material of at least one of the layers must extend into the material 
of the other layer and the material of the two adjacent layers must be of 
different compositions. Thus, at least some of the material of layer 62 
must extend into the material of layer 64 or at least some of the material 
of layer 64 must extend into the material of layer 64 or both. This is 
designated by numeral 10 in FIG. 3 which represents strands or filaments 
of material from layer 62 extending into the material of layer 64. 
Referring to FIG. 4, there is shown a fragmented view of a portion of a 
composite wicking material wherein at least some of the material of at 
least one layer extends into a second and third layer. The composite wick 
comprises a first layer or material 72, a second layer or material 74 and 
a third layer of material 76. At least some of the material of layer 72 
extends into the material of layer 74 and is designated by numeral 78. At 
least some of the material of layer 72 extends into the material of layer 
76 and is designated by numeral 90. Some of the material of layer 74 
extends into the material of layer 76 and is designated by numeral 70. 
The extending of the material of one layer into the material of the other 
layer is preferably accomplished by any of several well-known needling 
techniques such as described in U.S. Pat. Nos. 2,840,881 and 3,090,099, 
incorporated herein by reference. Therein is described the forming of a 
non-woven batt or layer of natural or synthetic staple fibers such as e.g. 
asbestos, wool, cotton, flax, jute, nylon, heat resistant nylons, viscose 
rayon, cellulose acetate, polyethyleneterephthalate, polyacrylonitrile, 
glass, polyvinylidene chloride and copolymers of polyvinylidene chloride 
with other monomers copolymerizable therewith. A batt or layer of 
non-woven polytetrafluoroethylene fibers is superposed over a non-woven 
fibrous batt or layer substantially free of polytetrafluoroethylene fibers 
and some of the polytetrafluoroethylene fibers are forcibly oriented 
angularly and/or perpendicular to the ultimate faces of the fibrous sheet. 
The perpendicularly oriented polytetrafluoroethylene fibers are extended 
into the non-woven batt or layer of non-polytetrafluoroethylene fibers to 
unite or combine the two separate batts or layers. Alternately the 
non-polytetrafluoroethylene fibers may be forced into the batt or layer of 
polytetrafluoroethylene fibers. To provide additional combining strength 
fibers from each batt may be forcibly extended and/or twisted into the 
other batt to increase fiber entanglements. Naturally it is within the 
scope of the present invention to provide a plurality of batts or layers 
to form the composite wick material having unexpectedly improved 
characteristics for applying release agents or fluids to fuser members in 
xerographic fuser assemblies. Any type of needle looming operation and 
needle profile may be used to extend the material of one or more layers 
into the material of one or more other layers. 
Although non-woven intermingled fibers forming batts are preferred in the 
layers of the present invention, other types of batts and webs can be used 
in accordance with the present invention as long as the batts and webs 
lend themselves to the needling process or its equivalent whereby strands, 
filaments or fibers can be extended from one layer into at least the next 
adjacent layer. In preferred wick composites at least one of the materials 
is primarily of non-woven intermingled fibers or a web of loosely 
interlocked fibers. In the most preferred wick composite, all layers or 
materials are primarily non-woven intermingled fibers. It is deemed within 
the scope of the present invention to utilize layers of woven materials 
through which strands of filaments of adjacent layers or batts of 
non-woven fibrous materials, can be extended. 
In the preferred utility of the composite wicking materials of the present 
invention, the first material (the working surface layer), that is the 
layer having a surface in contact with the fuser member, should have low 
friction, low affinity for molten toner and high thermal stability ranging 
up to 500.degree. F., and the second material (the fluid retention layer) 
should have high thermal stability ranging up to 500.degree. F. 
The fibers which make up the major portion of the composite felt-like 
products may be selected from a large group of fibers and includes: 
asbestos, wool, cotton, polytetrafluoroethylene, flax, jute, glass, nylon, 
viscose rayon, cellulose acetate, heat resistant nylon, polyester, 
polyethylene terephthalate, polyacrylonitrile, polyvinylidene chloride and 
copolymers of vinylidene chloride with other monomers copolymerizable 
therewith such as e.g. acrylonitrile and vinyl chloride. Other fibrous 
materials and impregnated fibrous materials can also be used in the 
instant wick composites. Although the density of the felt-like materials 
is not critical a preferred density range of these materials, e.g. Nomex, 
is about 0.01 to about 1.0 grams/cc. 
The denier of the fibers which may be used in carrying out this invention 
may vary. When polytetrafluoroethylene fibers are used as the first layer 
in contact with the fuser member, the preferred denier of the 
polytetrafluoroethylene fibers is less than 20; however, useful products 
can be made with much coarser fibers having a denier of 50 to 70, as well 
as fibers such as 3.0 denier or less. The denier of the fibers for the 
resilient batt to which the polytetrafluoroethylene fibers are attached 
may likewise vary over a wide range, there being no particular limits with 
respect to denier in either batt of fibers. The fibers may be straight or 
crimped. The length for the staple fibers forming the batt are not 
critical except for those limitations imposed by the card or other web 
forming apparatus. In the case of synthetic fibers forming the reinforcing 
woven fabric they may be formed from spun staple yarn or continuous 
filament yarn. The density of the polytetrafluoroethylene is not critical, 
the preferred density being about 0.5 grams/cc. 
The relative thickness of the polytetrafluoroethylene batt and the batt 
substantially free of polytetrafluoroethylene fibers if not critical. 
However, in the preferred embodiment the layer of polytetrafluoroethylene 
fibers is thinner than the other batt of fibers. One of the important 
features of the fibrous felt-like products of this invention is the low 
surface friction combined with resiliency of the entire structure. In two 
preferred wick composite materials, the polytetrafluoroethylene layer 
(Teflon) is about 0.035 inch (0.089 cm.) thick and the heat resistant 
nylon layer (a copolymer of meta-phenylenediamine) and isophthaloyl 
chloride known by the Du Pont trademark as Nomex is about 0.300 inch (0.84 
cm.) thick or 0.6 inch (Nylon) and 0.375 inch (Nomex). The needle density 
in this preferred composite is about 3,000 perforations per square inch. 
Other preferred wick composites include fibrous 
polytetrafluoroethylene/wool and fibrous polytetrafluoroethylene/fibrous 
polyester. 
By the terms "needling", "needle punching", "needle loomed", and "needle 
looming" as used throughout the specification and claims is meant forcibly 
oriented or orienting, respectively, fibers from one batt or layer into an 
adjacent batt or layer or into adjacent batts or layers by any method well 
known in the art. 
The composite wick materials of the present invention may be used to apply 
any of the well-known fluid release agents applied to fuser members 
including bare metal or coated fuser rolls, plates, belts, and the like to 
prevent offsetting of toner especially heated or molten toner to the fuser 
member surface. The release materials or agents include mineral oil, 
peanut oil, silicone oil, and mixtures and blends of said oils with other 
materials, polymer release fluids including those which having functional 
groups such as the mercapto-functional polyorganosiloxanes, and those 
which oxidize to form functional groups thereon. The improved wick 
composites having a working surface layer exhibiting lubricity (low 
friction) and a fluid retention layer having a high capacity for retaining 
release fluids are generally in the form of a resilient fibrous sheet and 
provide an excellent supply of the release fluid at the surface of the 
fuser member and uniformly meter the release fluid in controlled amounts 
upon the surface of the fuser member. The strands or fibers extending from 
layer to layer provide integrity and strength to the composite, eliminate 
stitching which is a barrier to uniform metering of release fluid, reduce 
loose surface fibers and fuzz which interfere with doctoring and cleaning, 
and provide for excellent fluid transfer or through-put from one layer of 
the composite to the next layer. 
The following examples further define and describe exemplary materials used 
as composite wick materials in a fuser assembly. The examples are intended 
to illustrate the various preferred embodiments of the present invention. 
EXAMPLE I 
Several stitched composite wick materials were used in test fixtures 
similar to the fuser assembly shown in FIG. 2. Silicone oil was used as 
the release fluid. Five different stitching configurations were used with 
wool, polyester and Nomex substrates covered with a working layer of 
Teflon. When compared with the non-stitched composite wick material of the 
present invention having an identical Teflon layer needled to the 
substrate layer, there was a 45-65% increase in the amount of silicone oil 
supplied to the fuser roll surface, the variation in the percentage 
improvement being dependent upon the material density. It was observed 
that the wicking rate for substrates tends to increase with a decrease in 
the density of the substrate layer. Thus, in accordance with this 
invention, a higher density wick can be used and can provide acceptable 
fluid application rates with a denser, stronger composite. 
EXAMPLE II 
Fuser wick composites were tested similar to Example I. A Teflon felt batt 
was stitched to a Nomex (heat resistant nylon) batt and a Teflon felt batt 
was stitched to a wool batt. The wicks were presoaked in silicone oil and 
placed in the fuser assembly fixture as in Example I. Dyed silicone oil 
was added to the pump, and the progress of the color was observed for each 
wick for fusing 30,000 copies. With stitched Teflon/wool composite the 
colored silicone oil barely reached the 14 inch (outer) edge of the fuser 
roll. The stitched Teflon/Nomex composite wicks performed similar to the 
Teflon/wool composite, however, there was still an insufficient supply of 
the silicone oil to the outer edge of the fuser roll, that is, the full 14 
inch width of the paper path. 
EXAMPLE III 
Needled wicks of Teflon/wool and Teflon/Nomex are tested as in Example II. 
Both needled composites performed superior to their counterparts in 
Example II. The needled wick composites meter or spread silicone oil 
substantially more uniformly across the entire 14 inch width of the fuser 
roll than the stitched wick composites. 
EXAMPLE IV 
Using a stitched Teflon/wool wick composite as in Example I, it was found 
that 31.1 microliters of silicone oil were transferred to each sheet of 14 
inch copy paper. Under identical conditions a needled Teflon/wool wick 
composite provided 32.5 microliters of silicone oil for each sheet of copy 
paper. This results in a uniformity factor of 0.403 for the stitched wick 
composite versus 0.834 for the needled wick composite or an improvement of 
107% in uniformity factor. 
EXAMPLE V 
Using a stitched and a needled Teflon/Nomex wick composite, both samples of 
Nomex having a density of 0.08 gram/cc, under conditions set forth in 
Example IV, the stitched composite supplied 59.50 microliters of silicone 
oil per copy of 14 inch paper and the needled composite supplied 62.67 
microliters of silicone oil per copy of 14 inch paper. This is equivalent 
to a 121% increase in uniformity of metering of the needled composite over 
the stitched composite. 
In accordance with the stated objects, an improved composite wick material 
has been demonstrated for metering and supplying silicone oil on fuser 
members. 
While the invention has been described with respect to preferred 
embodiments, it will be apparent that certain modifications and changes 
can be made without departing from the spirit and scope of the invention 
and therefore, it is intended that the foregoing disclosure be limited 
only by the claims appended hereto.