Wound magnetic roll developer tube and method of manufacture

A developer roll for use in an electrophotographic printing machine of the type having an electrostatic latent image recorded on a photoconductive member in which a voltage differential is applied between the roll and a region adjacent the roll is provided. The developer roll includes a wound roll of media and a layer of resin. The wound roll is formed from a sheet of the media. The layer of resin is applied to the periphery of the wound roll. The layer of resin and the roll of media are selected of materials to obtain a decay rate relating to the electrical response of the layer of resin to the applied voltage differential.

The present invention relates to a method and apparatus for developing a 
latent image. More specifically, the invention relates to a magnetic roll 
developer tubes for development systems. 
The features of the present invention are useful in the printing arts and 
more particularly in electrophotographic printing. In the well-known 
process of electrophotographic printing, a charge retentive surface, 
typically known as a photoreceptor, is electrostatically charged, and then 
exposed to a light pattern of an original image to selectively discharge 
the surface in accordance therewith. The resulting pattern of charged and 
discharged areas on the photoreceptor form an electrostatic charge 
pattern, known as a latent image, conforming to the original image. The 
latent image is developed by contacting it with a finely divided 
electrostatically attractable powder known as "toner." Toner is held on 
the image areas by the electrostatic charge on the photoreceptor surface. 
Thus, a toner image is produced in conformity with a light image of the 
original being reproduced. The toner image may then be transferred to a 
substrate or support member (e.g., paper), and the image affixed thereto 
to form a permanent record of the image to be reproduced. Subsequent to 
development, excess toner left on the charge retentive surface is cleaned 
from the surface. The process is useful for light lens copying from an 
original or printing electronically generated or stored originals such as 
with a raster output scanner (ROS), where a charged surface may be 
imagewise discharged in a variety of ways. 
In the process of electrophotographic printing, the step of conveying toner 
to the latent image on the photoreceptor is known as "development." The 
object of effective development of a latent image on the photoreceptor is 
to convey toner particles to the latent image at a controlled rate so that 
the toner particles effectively adhere electrostatically to the charged 
areas on the latent image. A commonly used technique for development is 
the use of a two-component developer material, which comprises, in 
addition to the toner particles which are intended to adhere to the 
photoreceptor, a quantity of magnetic carrier granules or beads. The toner 
particles adhere triboelectrically to the relatively large carrier beads, 
which are typically made of steel. When the developer material is placed 
in a magnetic field, the carrier beads with the toner particles thereon 
form what is known as a magnetic brush, wherein the carrier beads form 
relatively long chains which resemble the fibers of a brush. This magnetic 
brush is typically created by means of a "developer roll." The developer 
roll is typically in the form of a cylindrical sleeve rotating around a 
fixed assembly of permanent magnets. The carrier beads form chains 
extending from the surface of the developer roll, and the toner particles 
are electrostatically attracted to the chains of carrier beads. When the 
magnetic brush is introduced into a development zone adjacent the 
electrostatic latent image on a photoreceptor, the electrostatic charge on 
the photoreceptor will cause the toner particles to be pulled off the 
carrier beads and onto the photoreceptor. Another known development 
technique involves a single-component developer, that is, a developer 
which consists entirely of toner. In a common type of single-component 
system, each toner particle has both an electrostatic charge (to enable 
the particles to adhere to the photoreceptor) and magnetic properties (to 
allow the particles to be magnetically conveyed to the photoreceptor). 
Instead of using magnetic carrier beads to form a magnetic brush, the 
magnetized toner particles are caused to adhere directly to a developer 
roll. In the development zone adjacent the electrostatic latent image on a 
photoreceptor, the electrostatic charge on the photoreceptor will cause 
the toner particles to be attracted from the developer roll to the 
photoreceptor. 
An important variation to the general principle of development is the 
concept of jumping development. Jumping development consists of placing an 
alternating current bias between the donor roll/metering blade and the 
photoreceptor substrate. The alternating current on the donor 
roll/metering blade and the photoreceptor substrate causes the toner to 
jump from the donor roll to the latent image on the photoreceptor at the 
nip therebetween. A transition and back zone is formed in the nip where 
the toner moves to the photoreceptor and back to the donor roll. A second 
transition zone is formed immediately downstream of the transition and 
back zone in which toner moves to the photoreceptor in the image areas and 
in which toner moves from the photoreceptor to the donor roll in the 
non-image areas. Jumping development is disclosed in U.S. Pat. No. 
4,292,387 the relevant parts thereof are incorporated herein by reference. 
Another important variation to the general principle of development is the 
concept of "scavengeless" development. The purpose and function of 
scavengeless development are described more fully in, for example, U.S. 
Pat. No. 4,868,600 to Hays et al. U.S. Pat. No. 4,868,600 to Hays et al., 
which is hereby incorporated by reference. In a scavengeless development 
system, toner is detached from the donor roll by applying AC electric 
field to self-spaced electrode structures, commonly in the form of wires 
positioned in the nip between a donor roll and photoreceptor. This forms a 
toner powder cloud in the nip and the latent image attracts toner from the 
powder cloud thereto. Because there is no physical contact between the 
development apparatus and the photoreceptor, scavengeless development is 
useful for devices in which different types of toner are supplied onto the 
same photoreceptor such as in "tri-level"; "recharge, expose and develop"; 
"highlight"; .or "image on image" color xerography. 
A typical "hybrid" scavengeless development apparatus includes, within a 
developer housing, a transport roll, a donor roll, and an electrode 
structure. The transport roll advances carrier and toner to a loading zone 
adjacent the donor roll. The transport roll is electrically biased 
relative to the donor roll, so that the toner is attracted from the 
carrier to the donor roll. The donor roll advances toner from the loading 
zone to the development zone adjacent the photoreceptor. In the 
development zone, i.e., the nip between the donor roll and the 
photoreceptor, are the wires forming the electrode structure. During 
development of the latent image on the photoreceptor, the electrode wires 
are AC-biased relative to the donor roll to detach toner therefrom so as 
to form a toner powder cloud in the gap between the donor roll and the 
photoreceptor. The latent image on the photoreceptor attracts toner 
particles from the powder cloud forming a toner powder image thereon. 
Another variation on scavengeless development uses a single-component 
developer material. In a single component scavengeless development, the 
donor roll and the electrode structure create a toner powder cloud in the 
same manner as the above-described scavengeless development, but instead 
of using carrier and toner, only toner is used. 
As stated earlier, development is typically accomplished by the use of a 
magnetic brush. The magnetic brush is typically formed by a developer roll 
which is typically in the form of a cylindrical sleeve which rotates 
around a fixed assembly of permanent magnets. When utilizing magnetic 
brush-type development, the cylindrical sleeve is typically made of an 
electrically conductive, non-magnetically conductive material, for 
example, aluminum. 
When utilizing the jumping development and the (hybrid) scavengeless 
development described above, the developer roll typically includes a 
semi-conductive portion preferably on the periphery of the roll. The 
semi-conductive nature of the roll assists in the proper biasing of the 
roll with respect to the photoconductive surface onto which the toner is 
be deposited. 
An electrically semi-conductive roll has typically been made of an aluminum 
shell with an anodizing coating placed upon the outside periphery of the 
aluminum roll. The semi-conductive properties of the anodized layer vary 
widely and are not easily predicted. Also, the anodized layer of aluminum 
has a tendency to wear rapidly. 
Semi-conductive rolls have also been made utilizing an outer periphery of a 
phenolic. The phenolic is typically applied over a core of a conductive 
metallic material, for example, aluminum. The process of applying the 
phenolic material to the aluminum substrate is very expensive and time 
consuming. 
Phenolic coated developing rolls have been made with two thermoset 
processes. These two thermoset processes are distinct. The first of these 
processes consists of extruding from phenolic material a free standing 
tube with a wall thickness of 0.02 to 0.04 inches. Subsequent to the 
extruding of the free standing tube, a metal tube is inserted into the 
inner periphery of the free standing tube at a secondary operation. 
The second of the two thermoset extruding processes for manufacturing 
phenolic developing rolls is known as a cross head extrusion process. In 
this process, a metal tube is overcoated with a conductive phenolic 
coating during the extrusion process. 
Both of these processes require an extensive amount of expensive equipment 
as well as expensive custom dies for each particular developer roll size. 
The extrusion process is further limited to a particular conductivity of 
the phenolic coating. Further, the developer roll utilizing this process 
will only have a decay rate corresponding to the above conductivity range 
of the phenolic coating. Also, the extruder typically can only manufacture 
one developer roll at a time through the extruder. The limitations of this 
process to only manufacture one roll at a time results in a slow, 
expensive process. Also, the core of a extruded developer roll must be 
rigid to accommodate the conforming resin. 
The following disclosures may be relevant to various aspects of the present 
invention: 
U.S. Pat. No. 5,455,077 
Patentee: Yamamoto, et al. 
Issue Date: Oct. 3, 1995 
U.S. Pat. No. 5,448,342 
Patentee: Hays, et al. 
Issue Date: Sep. 5, 1995 
U.S. Pat. No. 5,416,566 
Patentee: Edmunds, et al. 
Issue Date: May 16, 1995 
U.S. Pat. No. 5,386,277 
Patentee: Hays, et al. 
Issue Date: Jan. 31, 1995 
U.S. Pat. No. 5,378,525 
Patentee: Yamamoto, et al 
Issue Date: Jan. 3, 1995 
U.S. Pat. No. 5,300,339 
Patentee: Hays, et al 
Issue Date: Apr. 5, 1994 
U.S. Pat. No. 5,245,392 
Patentee: Behe, et al. 
Issue Date: Sep. 14, 1993 
U.S. Pat. No. 5,177,538 
Patentee: Mammino, et al. 
Issue Date: Jan. 5, 1993 
U.S. Pat. No. 4,891,081 
Patentee: Takahashi, et al. 
Issue Date: Jan. 2, 1990 
U.S. Pat. No. 4,278,733 
Patentee: Benzinger 
Issue Date: Jul. 14, 1981 
U.S. Pat. No. 4,034,709 
Patentee: Fraser, et al. 
Issue Date: Jul. 12, 1977 
U.S. Pat. No. 3,616,046 
Patentee: Benzinger, et al. 
Issue Date: Oct. 26, 1971 
U.S. Pat. No. 5,455,077 discloses a crowned resilient roll of continuously 
increasing diameter from the axially opposed ends. The resilient roll 
includes a columnar roll body formed of a resilient material and a coating 
layer formed on an outer circumferential surface of the roll body. The 
coating is applied to a rotating body with the speed of the rotating body 
being decreased in the middle of the roll. 
U.S. Pat. No. 5,448,342 discloses a coated transport roll including a core 
with a coating of charge transporting molecules and an oxidizing agent 
dispersed in a resin. The transporting molecules includes aryldiamine 
molecules. 
U.S. Pat. No. 5,416,566 discloses a magnetic roll assembly including a 
rotatable non-conductive shell surrounding a magnetic member to prevent 
eddy currents during rotation. The substrate has an elastomer coating 
formed thereon. 
U.S. Pat. No. 5,386,277 discloses a coated toner transport roller including 
a core with a coating of an oxidized polyether carbonate. 
U.S. Pat. No. 5,378,525 discloses a crowned resilient roll of continuously 
increasing diameter from the axially opposed ends. The resilient roll 
includes a columnar roll body formed of a resilient material and a coating 
layer formed on an outer circumferential surface of the roll body. A 
protective layer of N-methoxymethlated nylon is applied to the coating. 
U.S. Pat. No. 5,300,339 discloses a coated toner transport roll containing 
a core with a coating of transporting molecules dispersed in a binder and 
an oxidizing agent of ferric chloride and/or trifluoroacetaic acid. The 
coating possesses a relaxation time of from about 0.0099 millisecond to 
about 3.5 milliseconds and a residual voltage of from about 1 to about 10 
volts. 
U.S. Pat. No. 5,245,392 discloses a donor roll for conveying toner in a 
development system. The roll includes a core of an electrically conductive 
material such as aluminum. The core is coated with a resin, for example a 
phenolic, to obtain a suitable conductivity to facilitate a discharge time 
constant of less than 300 microseconds. 
U.S. Pat. No. 5,177,538 discloses a donor roll for a printer formed by 
mixing resin particles with conductive particles and subsequently 
extruding or centrifugal casting the mixture into a cylindrical shell. The 
shell is cut to the desired length and journals are attached to each end 
of the shell. The resin particles are thermoset particles preferably 
phenolic resin particles, and the conductive particles are preferably 
graphite particles. 
U.S. Pat. No. 4,891,081 discloses a method of molding and a foamed resin 
molding in which a skin layer is formed by pressing an expandable film 
against and into conformity with cavity walls of a mold or a bag-like 
cover member by foaming pressure of a foamable resin and a foamed resin 
body molded concurrently and integrally under the skin layer. 
U.S. Pat. No. 4,278,733 discloses a laminate product and method of making 
the same involving a base material such as cellulose fibrous materials 
impregnated with a cured mixture of aniline, phenol, formaldehyde and 
epoxy resin, which laminate has electrical and mechanical properties with 
improved heat resistance over previous materials. 
U.S. Pat. No. 4,034,709 discloses a developer roll for a xerographic 
copier. The roll includes a tubular member made a non-magnetic metal for 
example aluminum. The roll is coated with a layer of styrene-butadiene. 
Magnets are disposed in the interior of the tubular member. 
U.S. Pat. No. 3,616,046 discloses a laminated product possessing good 
physical and electrical properties made with an impregnating resin which 
is a reaction product of aniline, phenol and formaldehyde. These resins 
impart unusually good electrical and physical properties to the laminated 
product and are sufficiently water soluble as to allow their water content 
to be adjusted for direct, one stage impregnation of cellulose fiber 
materials such as paper. 
In accordance with one aspect of the present invention, there is provided a 
developer roll for use in an electrophotographic printing machine of the 
type having an electrostatic latent image recorded on a photoconductive 
member in which a voltage differential is applied between the roll and a 
region adjacent the roll. The developer roll includes a wound roll of 
media and a resin. The wound roll is formed from a sheet of the media. The 
resin is applied to the periphery of the wound roll. The resin and the 
roll of media are selected of materials to obtain a decay rate relating to 
the electrical response of the roll to the applied voltage differential. 
In accordance with another aspect of the present invention, there is 
provided a developer unit for use in an electrophotographic printing 
machine of the type having an electrostatic latent image recorded on a 
photoconductive member in which a voltage differential is applied between 
the unit and a region adjacent the unit. The developer unit includes a 
housing defining a chamber for storing a supply of toner particles therein 
and a developer roll for transporting the toner particles on a surface 
thereof from the chamber of the housing to the member. The developer roll 
further includes a wound roll of media. The wound roll is formed from a 
sheet of the media and a resin applied to the periphery of the wound roll. 
The resin and the roll of media are selected of materials to obtain a 
decay rate relating to the electrical response of the roll to the applied 
voltage differential. 
In accordance with yet another aspect of the present invention, there is 
provided an electrographic printing machine of the type having an 
electrostatic latent image recorded on a photoconductive member in which a 
voltage differential is applied between the unit and a region adjacent the 
unit. The printing machine includes a housing defining a chamber for 
storing a supply of toner particles therein and a developer roll for 
transporting the toner particles on a surface thereof from the chamber of 
the housing to the member. The developer roll further includes a wound 
roll of media. The wound roll is formed from a sheet of the media and a 
resin applied to the periphery of the wound roll. The resin and the roll 
of media are selected of materials to obtain a decay rate relating to the 
electrical response of the roll to the applied voltage differential. 
In accordance with a further aspect of the present invention, there is 
provided a method for manufacturing a developer roll for use in an 
electrophotographic printing machine of the type having an electrostatic 
latent image recorded on a photoconductive member in which a voltage 
differential is applied between the unit and a region adjacent the unit. 
The method includes the steps of forming a media including filaments into 
a sheet, impregnating the media with a resin wherein the resin and the 
roll of media are selected of materials to obtain a decay rate relating to 
the electrical response of the layer of the roll to the applied voltage 
differential, and rolling the sheet around the periphery of a mandrel.

While the present invention will be described in connection with a 
preferred embodiment thereof, it will be understood that it is not 
intended to limit the invention to that embodiment. On the contrary, it is 
intended to cover all alternatives, modifications, and equivalents as may 
be included within the spirit and scope of the invention as defined by the 
appended claims, 
For a general understanding of the illustrative electrophotographic 
printing machine incorporating the features of the present invention 
therein, reference is made to the drawings. In the drawings, like 
reference numerals have been used throughout to designate identical 
elements. FIG. 3 schematically depicts the various components of an 
electrophotographic printing machine incorporating the developing device 
of the present invention therein. Although the developing device of the 
present invention is particularly well adapted for use in the illustrative 
printing machine, it will become evident that the developing device is 
equally well suited for use in a wide variety of printing machines and are 
not necessarily limited in its application to the particular embodiment 
shown herein. 
Referring now to FIG. 3, the electrophotographic printing machine shown 
employs a photoconductive drum 16, although photoreceptors in the form of 
a belt are also known, and may be substituted therefor. The drum 16 has a 
photoconductive surface deposited on a conductive substrate. Drum 16 moves 
in the direction of arrow 18 to advance successive portions thereof 
sequentially through the various processing stations disposed about the 
path of movement thereof. Motor 20 rotates drum 16 to advance drum 16 in 
the direction of arrow 18. Drum 16 is coupled to motor 20 by suitable 
means such as a drive. 
Initially successive portions of drum 16 pass through charging station A. 
At charging station A, a corona generating device, indicated generally by 
the reference numeral 30, charges the drum 16 to a selectively high 
uniform electrical potential, preferably negative. Any suitable control, 
well known in the art, may be employed for controlling the corona 
generating device 30. 
A document to be reproduced is placed on a platen 22, located at imaging 
station B, where it is illuminated in known manner by a light source such 
as a tungsten halogen lamp 24. The document thus exposed is imaged onto 
the drum 16 by a system of mirrors 26, as shown. The optical image 
selectively discharges surface 28 of the drum 16 in an image configuration 
whereby an electrostatic latent image 32 of the original document is 
recorded on the drum 16 at the imaging station B. 
At development station C, a magnetic development system or unit, indicated 
generally by the reference numeral 36 advances developer materials into 
contact with the electrostatic latent images. Preferably, the magnetic 
developer unit includes a magnetic developer roller mounted in a housing. 
Thus, developer unit 36 contains a magnetic roller 40. The roller 40 
advances toner particles into contact with the latent image. Appropriate 
developer biasing is may be accomplished via power supply 42, electrically 
connected to developer unit 36. 
The developer unit 36 develops the charged image areas of the 
photoconductive surface. This developer unit contains magnetic black 
toner, for example, particles 44 which are charged by the electrostatic 
field existing between the photoconductive surface and the electrically 
biased developer roll in the developer unit. Power supply 42 electrically 
biases the magnetic roll 40. 
A sheet of support material 58 is moved into contact with the toner image 
at transfer station D. The sheet of support material is advanced to 
transfer station D by a suitable sheet feeding apparatus, not shown. 
Preferably, the sheet feeding apparatus includes a feed roll contacting 
the uppermost sheet of a stack copy sheets. Feed rolls rotate so as to 
advance the uppermost sheet from the stack into a chute which directs the 
advancing sheet of support material into contact with the photoconductive 
surface of drum 16 in a timed sequence so that the toner powder image 
developed thereon contacts the advancing sheet of support material at 
transfer station D. 
Transfer station D includes a corona generating device 60 which sprays ions 
of a suitable polarity onto the backside of sheet 58. This attracts the 
toner powder image from the drum 16 to sheet 58. After transfer, the sheet 
continues to move, in the direction of arrow 62, onto a conveyor (not 
shown) which advances the sheet to fusing station E. 
Fusing station E includes a fuser assembly, indicated generally by the 
reference numeral 64, which permanently affixes the transferred powder 
image to sheet 58. Preferably, fuser assembly 64 comprises a heated fuser 
roller 66 and a pressure roller 68. Sheet 58 passes between fuser roller 
66 and pressure roller 68 with the toner powder image contacting fuser 
roller 66. In this manner, the toner powder image is permanently affixed 
to sheet 58. After fusing, a chute, not shown, guides the advancing sheet 
58 to a catch tray, also not shown, for subsequent removal from the 
printing machine by the operator. It will also be understood that other 
post-fusing operations can be included, for example, stapling, binding, 
inverting and returning the sheet for duplexing and the like. 
After the sheet of support material is separated from the photoconductive 
surface of drum 16, the residual toner particles carried by image and the 
non-image areas on the photoconductive surface are charged to a suitable 
polarity and level by a preclean charging device 72 to enable removal 
therefrom. These particles are removed at cleaning station F. The vacuum 
assisted, electrostatic, brush cleaner unit 70 is disposed at the cleaner 
station F. The cleaner unit has two brush rolls that rotate at relatively 
high speeds which creates mechanical forces that tend to sweep the 
residual toner particles into an air stream (provided by a vacuum source), 
and then into a waste container. Subsequent to cleaning, a discharge lamp 
or corona generating device (not shown) dissipates any residual 
electrostatic charge remaining prior to the charging thereof for the next 
successive imaging cycle. 
It is believed that the foregoing description is sufficient for purposes of 
the present application to illustrate the general operation of an 
electrophotographic printing machine incorporating the development 
apparatus of the present invention therein. 
According to the present invention and referring to FIG. 2, a conductive 
sheet 100 is shown for use in manufacturing the wound magnetic roll 
developer tube of the present invention. The sheet 100 of media is made 
from a media 102 which may be any suitable material capable of absorbing a 
resin 104. Any wrapable or windable media can be used. For example, the 
media 102 may be a woven fiber cloth or a paper. For example, the paper 
may be a Kraft paper. The paper or cloth or other suitable media may be 
impregnated with a conductive material, for example, carbon fibers. 
The resin 104 may be any suitable thermoset or thermoplastic resin. For 
example, the thermoset resins may include phenolics or epoxies. The resins 
may be conductive or semi-conductive. The level of 
conductivity/resistivity of the resin may be controlled by the amount or 
type of additive to the phenolic material. 
While the invention is preferably practiced with a sheet of media 100, it 
should be appreciated that the invention may be practiced utilizing a 
filament winding process. Filament winding is the process of wrapping 
resin-impregnated continuous fiber windings around a suitable mold or 
mandrel to produce a finished product. This process will be described in 
greater detail later. 
The media 102 may be conductive or non-conductive, while the resin 104 may 
be conductive or semi-conductive. The combination of varying the 
conductivities of both the media 102 and the resin 104 permits a wide 
range and reasonably tight control of the conductivity/resistivity of the 
sheet of media 100. 
The sheet of media 100 may have any particular size depending on the size 
of the developer roll to manufactured. For example, for a developer roll 
having a length L, the sheet of media preferably has a length L roughly 
identical to the length of the roll. To permit the copying of a sheet of 
81/2".times.11" piece of paper both lengthwise and crosswise, the length L 
is typically slightly larger than 11 inches. The sheet of media 100 is 
wound into cylindrical roll and therefore has a predetermined width W 
which may be described by the following: 
EQU W=C.times.N.sub.F +C.times.N.sub.M 
where: 
C=the circumference of the roll; 
N.sub.F =the number of layers of the sheet of media in the finished 
developer roll; and 
N.sub.M =the number of windings of the sheet of media which are 
subsequently removed in the machining process. 
The sheet of media 100 may have any suitable thickness, but the applicants 
have found that a sheet of media 100 having thickness T of approximately 
0.004 to 0.007 inches performs satisfactorily. For the thickness of the 
media 102 of 0.004 to 0.007 inches, the sheet when impregnated with resin 
104 has an impregnated thickness of approximately 0.006 to 0.010 inches. 
Referring now to FIG. 1, sheet of media 100 is shown wound about mandrel 
106. The mandrel 106 may have any suitable shape suitable for winding the 
sheet of media 100 into roll 110 of media. Preferably the mandrel 106 has 
a cylindrical shape is made of a suitable, durable material, for example, 
steel or aluminum. The resistivity of sheet of media 100 is probably 
selected to obtain the proper operating conditions. For example, for a 
semi-conductive developing roll, the resin 104 and media 102 are selected 
to have a resistivity from 10.sup.1 to 10.sup.9 ohms. 
Referring now to FIG. 2A, a process for applying resin 104 into the media 
102 is shown. It should be appreciated that other coating operations or 
methods including but not limited to dipping or spraying may be used The 
resin 10 is stored in a tank 114. The media 102 is fed into the tank 114 
with the media 102 being submersed within the resin 104 in the tank 114. 
The sheet 100 may be permitted to be raised and lowered above and below 
the level of the media 102 to permit partial drying of the resin 104 
within the media 102. To obtain a constant thickness for the sheet of 
media 100, the sheet of media 100 may be squeezed between a set of rolls 
116 upon exit from the tank 114. 
After the coating operation, the sheet 100 of media is partially cured and 
chemically cross-linking the resin. The roll 100 is processed to a "B" 
stage which is dry to the touch, not tacky and not fully cured. 
Referring again to FIG. 1, the "B" stage sheet 100 is wrapped about mandrel 
106 to form roll 110 of media. The sheet 100 is fed between a set of rolls 
122 including a heated roll 124 and a pressure roll 126. It should be 
appreciated that heat may be added to sheet 100 in any suitable way such 
as by induction heating, or conduction or convection heating the sheet 100 
directly. The mandrel 106 is rotated in the direction of arrow 130 to 
permit the sheet 100 to wrap about the mandrel 106. The rotational 
velocity of the mandrel 106 and the linear velocity of the sheet 100 
entering the mandrel 106 are controlled to provide for the proper tension 
upon the sheet 100 to properly form the roll 110 of media. 
The mandrel 106 has an unfinished diameter D.sub.U which is of sufficient 
size to provide for a finished diameter D.sub.F of the roll 110 as well as 
a thickness T.sub.F of the roll. The applicants have found that for a roll 
with a finished diameter D.sub.F of approximately 0.8 inches, the mandrel 
preferably has a diameter of 0.75 inches. The finished thickness T.sub.F 
of the roll in this case is approximately 0.025 inches. For a sheet 100 
with a thickness T of approximately 0.006 inches, this represents four 
revolutions or wraps of the sheet 100 about mandrel 106. To permit 
subsequent machining of the roll 110, the unfinished roll diameter D.sub.U 
prior to machining is substantially larger than the finished roll diameter 
D.sub.F of the roll 110. Applicants have found that an unfinished roll 
diameter D.sub.U of approximately 0.80 inches is sufficient for use with a 
finished diameter D.sub.F of approximately 0.75 inches. When using a sheet 
100 with a thickness T of approximately 0.006 inches, the sheet 100 has 
four revolutions of wraps about mandrel 106 to accommodate the portion of 
the roll 110 which is machined away in a subsequent operation. The heating 
of the sheet 100 with heated roll 124 serves to fuse the outer edge or 
seam 132 of the roll 110. 
Referring now to FIG. 4, the roll 110 is shown subsequent to machining. For 
a roll with a finished diameter D.sub.F of approximately 0.80 inches wound 
about a mandrel with unfinished diameter D.sub.U (see FIG. 1) of 0.75 
inches, the sheet 100 is wound about approximately four revolutions. Each 
of the layers of the sheet have a thickness of approximately 0.006 inches. 
Seam 132 is formed at the periphery of roll 110. Roll 110 is shown with 
mandrel 106 (see FIG. 1) removed therefrom. 
While the invention may be practiced with roll 110 consisting essentially 
of the roll 110 of media, the invention may be alternatively practiced 
with the mandrel serving also as a core for the roll. The use of the 
mandrel as a core will tend to strengthen the roll and if the mandrel is 
made from an electrically conductive material, the mandrel may serve to 
conduct an electrical bias to the roll. 
For example, referring to FIG. 8, developer roll 200 is shown. The 
developer roll 200 includes sleeve 214. Sleeve 214 includes core 210 as 
well as resin impregnated tube 216 which is located on core 210. Tube 216 
is similar to developer roll 110 of FIG. 4. Tube 216 of FIG. 5 is 
constructed of similar materials in a similar fashion to roll 110 of FIG. 
4. The core 210 serves as the mandrel, as in mandrel 106 of FIG. 1. 
The core 210 may be made of any suitable, durable material, but preferably 
is made of an electrically conductive material, for example, a metal. 
Preferably, the core 210 is made of a non-magnetic metal, for example, 
aluminum. The core may add any suitable shape, but preferably has a 
cylindrical shape. The core 210 may be solid, but for use with a roller 
for magnetic brush development, the core 210 is hollow. The core 210 has a 
length L.sub.C approximately equal to the length L of the roll 200. The 
core 210 has bore diameter D.sub.B which is slightly smaller than core 
diameter D.sub.C of outer periphery 220 of the core 210. The core diameter 
D.sub.C is sufficiently larger than the bore diameter D.sub.B of bore 218 
to provide adequate stiffness for the developer roll 200. For example, for 
a developer roll 200 having a bore 218 with bore diameter D.sub.B of 
approximately 0.70 inches, the core diameter D.sub.C of the core 210 is 
approximately 0.75 inches for a core 210 made of aluminum. 
Applicants have found that with the use of a core 210 with a core diameter 
D.sub.C of approximately 0.75 inches, finished diameter D.sub.F of the 
sleeve 214 of approximately 0.80 inches is acceptable. 
Referring now to FIG. 6, a magnet 222 for use with the sleeve 214 (see FIG. 
5) is shown in FIG. 6. The magnet 222 may have any suitable shape, but 
preferably has a cylindrical body 224 as well as first and second stems 
226 and 230, respectively, which extend outwardly from first and second 
ends 232 and 234, respectively, of the body 224. The body 224 is made of 
any material having a ferromagnetic property and preferably is made of a 
permanent magnet material. The first and second stems 226 and 230 are made 
of any suitable, durable material, for example, steel. The body 224 has a 
body diameter D.sub.M which is slightly smaller than the bore diameter 
D.sub.B of the bore of the sleeve 214 (see FIG. 5). Body 224 is thus able 
to rotate within the sleeve 214. 
The body 224 has a length L.sub.M which is smaller than length L.sub.S of 
the sleeve 214. The magnet 222 has a overall length Lo which is 
significantly than length L.sub.S of the sleeve 214 (see FIG. 5). 
Referring now to FIGS. 7A and 7B, plugs 240 and 242 are shown. First and 
second plugs 240 and 242, respectively, serve to support the magnet 222 
and permit the magnet 222 to rotate within the sleeve 214 (see FIG. 5). 
The first plug 240 includes outer diameter 244 which is fitted within bore 
218 of the sleeve 214 at first end 246 of sleeve 214 (see FIG. 5). 
Similarly, second plug 242 includes outer diameter 250 which is fitted to 
bore 218 of sleeve 214 at second end 252. First plug 240 further includes 
a first plug bore 254 to which stem 226 is slidably located. Similarly, 
the second plug 242 includes second plug bore 256 to which second stem 230 
is slidably fitted. First plug and second plug, 240 and 242, respectively, 
are made of any suitable, durable material capable of performing the 
desired functions of the roll 200. Preferably, first plug and second plug 
240 and 242 are made of a magnetically non-conductive material. Further, 
the first and second plugs 240 and 242 are preferably made of an 
electrically conductive material to transmit an electrical bias from the 
plugs 240 and 242 to the core 210 of the sleeve 214 (see FIG. 5). Aluminum 
is a suitable magnetic non-conductor and electrical conductor and is 
suitable for this application. 
Referring again to FIG. 8, developer roll 200 is shown with the magnet 222 
installed within sleeve 214. Plugs 240 and 242 provide the support for 
magnet 222 within the sleeve 214. 
Electrical bias is applied to the plugs 240 and 242 and passes through core 
210 of sleeve 214 and through the resin impregnated tube 216 to the 
periphery 260 of the developer roll 200. 
Referring now to FIG. 9, an alternate process for making a resin 
impregnated tube according to the present invention is shown in FIG. 9. 
Mandrel 308 is similar to mandrel 118 of FIG. 1. Roll 320 of media of FIG. 
9 is similar to roll of media 120 of FIG. 1, except that media 102 of FIG. 
2 which is made of paper is replaced by non-conductive filaments 302. The 
filaments may be made of any suitable material, for example 
carbon/graphite or glass. The filaments may be made of glass. In this 
process, the glass filaments 302 are coated with liquid resin 310 located 
in resin bath 312. The glass filaments 302 are fed from glass creels 314 
through a glass guide 316 into the resin bath 312. From the resin bath 
312, the glass filaments 302 which now are coated with resin 310 are 
separated through a comb or eyelet 322 and are finally gathered together 
by yoke 324 and twisted about mandrel 308. The mandrel 308 rotates while 
the filaments 302 are fed through the yoke 324 while the yoke 324 moves up 
and down the length of the mandrel 308. The mandrel is then treated and 
the part is cured. The molded parts may require oven curing. Impregnated 
and partially cured reinforcing tapes may also used for filament windings. 
These are commonly used for products of unusual shapes. 
By providing a developer roll according to the present invention with a 
wound magnetic roll developer tube, a developer tube that only requires 
low cost tooling including a mandrel, is provided. 
By providing a wound magnetic roller including media and resin which media 
and resin can both be modified to provide various conductivity ranges, a 
developer roll can be provided with a widely varied and accurately 
maintained conductivity range. 
By providing a wound magnetic roll developer tube with controllable 
conductivity resins and controllable conductivity media, a developer roll 
with an accurate, specific decay rate can be provided. 
By providing a wound magnetic roll developer tube which may be wound about 
a mandrel, many parts may be simultaneously manufactured at one time. 
By providing a wound magnetic roll developer tube, various conductive 
mediums including paper, wound fabrics, fillers, and non-conductive 
filaments can be used to provide the developer tube. 
By utilizing wound magnetic roll developer tools, a wide variety of resins 
can be used which have a wide range of conductivity and decay rates. These 
materials may include thermoset resins such as phenolics, polyesters and 
epoxies as well as thermoplastics. 
By providing a wound magnetic roll developer tube, a roll can be provided 
with a specific decay rate which may be used as a donor roll for hybrid 
scavengeless development or for jumping development. 
While this invention has been described in conjunction with various 
embodiments, it is evident that many alternatives, modifications, and 
variations will be apparent to those skilled in the art. Accordingly, it 
is intended to embrace all such alternatives, modifications, and 
variations as fall within the spirit and broad scope of the appended 
claims.