Note: Descriptions are shown in the official language in which they were submitted.
MAGNETIC COLORED ENCAPSULATED TONER COMPOSITIONS
BACKGROUND OF THE INVENTION
The present invention is generally directed to toner
compositions, and more specifically to colored encapsulated toner
compositions. In one embodiment, the present invention is related to
magnetic colored encapsulated toner cornpositions comprised of a core and
a polymeric shell thereover preferably prepared by interfacial
polymerization, which shell may contain a silane component derived from
the reaction of organosilane reagents such as a functionalized alkoxysilane,
a siloxysilane, and the like, with shell precursor materials. An embodiment
of the present invention relates to conductive colored, other than black,
encapsulated toner compositions suitable for inductive single component
development with no carrier component, which toner composition is
comprised of a core comprised of a suitable polymer resin, a colorless or
lightly colored such as grayish light orange, or a light b!own magnetic
material, such as iron powders, iron oxides, surface treated or surface
coated magnetic pigments, finely divided magnetic particles dispersed in
polymeric and the like, a whitening agent, and dye or pigment particles,
which core is encapsulated by a polymeric shell, such as a polyurea,
polyurethane, polyamide, polyester, mixtures thereof, and the like, and
which shell also has incorporated therein, orthereon a layerof a conductive
component. The core resin for the encapsulated toners of the present
invention may also contain a siloxane or polysiloxane moiety to enhance its
release property. In an embodiment of the present invention there can be
selected for the magnetic material a grayish colored iron powder, Sicopur
4068 available from BASF, which iron powder it is believed has a high
saturation magnetic moment of over 90 emu per gram. In another
embodiment of the present invention, there is provided a colored single
component encapsulated toner composition comprising a core comprised
of, for example, a methacrylate polymer resin or the copolymers thereof, a
colorant, such as cyan, magenta, yellow, or other colored pigments or dyes,
mixturff thereof, and the like, Sicopur 4068 iron powder, and a whitener
such as titanium dioxide or tin dioxide powder; and wherein the
. , .
-2- 2V~l9~
aforementioned core is encapsulated in a polymeric shell, and which shell
can be coated ~vith a layer of conductive agents. In an embodiment of the
present invention, there are provided single component magnetic colored
encapsulated toner compositions comprised of a polymeric shell obtained
by interfacial polymerization, and a core comprised of polymers obtained
preferably by free radical polymerization, colorants, an iron powder or
other colorless or lightly colored magnetic material with a particle size
diameter of from about 0.1 to about 8 microns, and a whitener comprised
of a white inorganic pigment such as titanium dixoide, tin dixoide or other
whitening agents, and wherein the toner surface is coated, for example, by
dry blending process with a conductive powder. In another embodiment,
the present invention relates to a magnetic colored encapsulated toner
composition without the aforementioned surface conductive layer, which
toner composition is especially useful for xerographic process wherein
image toning and transfer are accomplished electrostatically, and the fixing
of the image on paper is achieved in a separate step with a pressure roll.
Examples of advantages associated with many of the toner compositions of
the present invention include excellent color quality and color variety,
improved toner fixing characteristics, suitability for use in the ionographic
imaging systems, such as Delphax S6000~, S4500~, S3000-" and Xerox
Corporation 4075~, which employ inductive single component
development systems, suitability for highlight color imaging processes, the
elimination or the minimization of image ghosting, superior release
properties enabling their selection, for example, in imaging systems
wherein a release fluid, such as a silicone oil, is avoided, no or minimal
toner agglomeration, excellent powder flow characteristics, no or minimal
Ieaching of the core components, and avoidance of core resin component
adherence to, for example, dielectric receivers or photoreceptors. The
toner compositions of the present invention can be selected for a variety of
known reprographic imaging processes including electrophotographic and
ionographic processes. In an embodiment, the toner compositions are
selected for pressure fixing processes wherein the image is fixed onto paper
with pressure. Pressure fixing is utilized in some reprographic imaging
processes. In ~ome ionographic processes, latent
images ~re fir~t gener~t~d on a dlelectric rece~ver
such as silicon carb~de, reference U.S. Pat~nt 4,885,220.
The latent images are toned with ~ conductivQ toner by
inductive single component development, and transferred and fixed
simultaneously (transfix) in one single step onto paper with pressure.
Specifically, the toner compositions of the present invention can be
selected for known inductive single component developmet processes, such
as those utilized in the Delphax based ionographic printers. This printing
process involves the generation of latent images on a dielectric receiver
with an ion deposition head, toning the images with a conductive toner
encapsulated toner of the present invention by inductive development, and
transfixing to paper with an applied pressure of, for example, from about
1,000 to about S,000 psi. The toner of the present invention can be selected
for the generation of colored images in the commercial Delphax printers
such as the Delphax S9000~, S6000~, 54500~, S3000"', and Xerox
Corporation printers such as the 4060~ and 4075~ wherein, for example,
transfixing is utilized. The toner compositions of the present invention are
particularly useful for highlight colored imaging processes as indicated
herein. In another embodiment of the present invention, the toner
compositions of the present invention can be rendered insulative without
the application of a surface condùctive coating, and can thus, for example,
be utilized in xerographic imaging and printing apparatuses wherein image
toning and transfer are accomplished electrostatically, and transferred
images are fixed in a separate step by means of a pressure roll with or
without the assistance of thermal energy fusing.
The toner compositions of the present invention can, in one
specific embodiment, be prepared by a number of methods including first
dispersing the toner precursor materials into stabilized microdroplets of
controlled droplet size and size distribution, followed by shell formation
around the microdroplets via interfacial polymerization, and subsequently
generating the core polymer resin by in situ addition polymerization,
preferably free radical polymerization within the newly formed
~4~ 2a~19~n
microcapsules. The encapsulated particles thus obtained can be washed,
dried, and surface treated with conductive additives by dry blending
process to impart to the particles the required conductivity characteristics.
In one embodiment, the present invention is directed to a process for the
simple, and economical preparation of pressure fixable magnetic colored
encapsulated toner compositions by interfacial/free radical polymerization
methods wherein there are selected as the core polymer resin precursors an
addition-type monomer or monomers, a colored, other than black, pigment
or dye, a colorless or lightly colored magnetic material of high magnetic
saturation moment, a whitening agent, shell-forming monomers, and
conductive inorganic powders, such as tin oxide, electroconducting powder
T-1 obtained from Mitsubishi Chemical, the tin/antimony oxides KW175 of
Magnesium Electron Inc., the coated titanium oxide, electroconducting
powder W-1 and W-10 of Mitsubishi, KW375 of Magnesium Electron Inc.,
the electroconducting white pigment of Tioxide, the electroconducting
pigment of Sumimoto Cement Company, and the like as the surface
conductive agents. The particle diameter of the above mentioned
conductive powder is generally less than one micron, and preferably less
than 0.1 micron. The effective amount of the conductive agent is, for
example, from 0.1 to about 15 weight percent, and preferably ranges from
about 0.5 to about 10 weight percent. Other process embodiments of the
present invention relate to, for example, interfacial/free radical
polymerization processes for obtaining magnetic colored encapsulated
toner compositions. Further, in another process aspect of the present
invention the encapsulated toners can be prepared without organic
solvents as the diluting vehicle or as a reaction medium, thus eliminating
explosion hazards associated therewith, and these processes, therefore, do
not require expensive and hazardous solvent separation and recovery steps.
Encapsulated and cold pressure fixable toner compositions are
known. Cold pressure fixable toners have a number of known advantages
in comparison to toners that are fused by heat, primarily relating to the
utilization of less energy since the toner compositions used can be fused at
room temperature. Nevertheless, many of the prior art cold pressure
-s- 2~940
fixable toner compositions, and in particular the magnetic colored toners,
suffer from a number of deficiencies. Many of the prior art cold pressure
fixable colored toners are insulative, and cannot effectively, it is believed,
be utilized for the Delphax based inductive single component
development. Also, in a number of instances some of the prior art cold
pressure fixable colored toners are generally dull in color quality and do not
offer a wide selection of color variety. Furthermore, some of the prior art
toners do not contain a sufficient amount of magnetic materials to provide
the required magnetic prope ty for use in the Delphax ionography
technology. Moreover, the above mentioned prior art toner compositions
generally require high pressure for image fixing, and this usually leads to
undesirably high image gloss and paper calendering problem.
Furthermore, most of the prior art cold pressure fixable toners are prepared
by conventional melt blending process, which process can produce larger
toner sizes, generally of the order of over 20 microns in average particle
diameter, and the large toner size usually does not effectively satisfy the
requirements for high image resolution. Also, with some of the prior art
cold pressure toner compositions, substantial image smearing can result
because of their low fixing characteristics. Additionally, for encapsulated
toner compositions, the preparative processes of the prior art in many
instances employ organic solvents as the diluting vehicles and reaction
media, and these could increase the toner's manufacturing cost because of
the expensive solvent separation and recovery procedure, and the
necessary precautions that have to be undertaken to prevent the solvent
associated hazards. Moreover, the involvement of an organic solvent in the
prior art processes also decreases the product yield per unit volume of
reactor size. The solvents in many prior art processes may also have
deleterious effects on toner particle morphology and bulk density as a
result of their removal from the toner particles during the toner isolation
stage, thus causing shrinkage or collapse of the toner particles, resulting in
a toner of very low bulk density, which disadvantages are substantially
eliminated with the process of the present invention in embodiments
thereof. In addition, with many of the prior art conventional melt blended
~19~
-6-
processes, narrowed size distribution toner particles cannot usually be
obtained without the conventional particle size classification step as
contrasted with the process of the present invention wherein narrowed size
distribution toner particles can be obtained without the additional
classification step in an embodiment thereof. Specifically, thus with the
magnetic colored encapsulated toners of the present invention, control of
the toner properties, such as color variety and shade, image fixing
chracteristics, surface conductivity, toner mechanical integrity, shelf life,
thermal stability, and the like can be desirably achieved. More specifically,
with the magnetic colored encapsulated toners of the present invention in
embodiments thereof, excellent color quality and a wide selection of color
variety and shade can be obtained, the leaching or loss of core components
from the encapsulated toner can be avoided or minimized, and image
ghosting associated with ionographic transfix development is eliminated or
minimized in many instances. Image ghosting is one of the common
phenomena in the transfix ionographic printing processes. This refers to
the unwarranted repetitious generation of images, and is related to the
contamination of dielectric receiver by residual toner materials which
cannot be readily removed in the cleaning process. The result is the
retention of latent images on the dielectric receiver surface after cleaning,
and the subsequent unwarranted development of these images. One of
the common causes of image ghosting is related to the adherence of
residual toner materials to the dielectric receiver during the image
development process, and this is intimately related to the poor shell and
core materials properties.
Also, encapsulated toners with core containing relatively high
Ioadings of, for example, 30 to 70 weight percent of magnetic material are
usually black or intensely dark in color even when bright colorants are
present in the core. These toners usually cannot be effectively selected for
the generation of brilliant colored images, especially images of high color
quality. In addition, to be suitable for inductive single component
development, especially for use in the Delphax type printers, it is desirable
for the toner to possess a high saturation magnetic moment of from about
7- ~419~0
30 to about 60 emu per gram, as well as a volume resistivity in the range of
about 103 to about 108 ohm-cm. The encapsulated colored toners of the
present invention satisfy not only all the magnetic and resistivity
requirements, but also offer other features such as high image fix, brilliant
color, a wide spectrum of color variety and shade, excellent toner flow,
nonagglomerating and nonghosting characteristics, and excellent
suitability for pressure transfix under low pressure transfix conditions.
Furthermore, the prior art encapsulated toners are not suitable for the
provision of quality colored images.
In a patentability search report, there were listed the following
United States patents: 4,199,614 which relates to transparent magnetic
materials and electrostatographic processes thereof, and wherein the
magnetic composite particles are prepared by a solution phase thermal
decomposition of certain metal carbonyls, reference the Abstract of the
Disclosure, and wherein these particles may be combined with coloring
dyes or pigments according to the aforementioned report; 4,238,558 and
4,245,026 relating to magnetic polymer carrier materials wherein iron
carbonyl can be selected in forming the carrier particles, reference for
example the Abstracts of the Disclosures; and as background interest
4,443,527; 4,448,870; 4,486,523; 4,543,312 and 4,758,490.
There is disclosed in U.S. Patent 4,803,143 a heat fusible
insulative single component colored toner which is obtained by
conventional melt blending milling processes. U.S. Patent 4,238,558 is
directed to the production of low optical density polymer systems
impregnated with very fine metal or metal oxide particles for the
preparation of conventional colored toners; U.S. Patent 4,474,866 discloses
an ion exchange resin with trapped fine magnetic particles which can be
used for the preparation of magnetic colored toners; 4,770,968 is directed
to polysiloxane butadiene terpolymer toner resins, reference for example
column 4, and note the formulas of Figures 1 to 6, including Figure 2B,
which toners can be selected wherein silicone release oils are avoided;
4,814,253 is directed to encapsulated toners comprised of domains
containing a polymer component having dispersed therein a release
-8-
composition and thereover a host resin component comprised of toner
resin particles and pigment particles, see for example the Abstract of the
Disclosure and column 4, and note column 4 wherein there is illustrated as
one of the components of the encapsulated toner domains comprised of
styrene butadiene block polymers, such as Kraton, styrene copolymers, or
styrene siloxanes, which components have entrapped or dissolved therein
mineral oils or silicon oils; and as background interest 4,430,408 relating to
developer compositions containing a fluorene modified alkyl siloxane and a
surface treatment carbon black, reference the Abstract of the Disclosure,
for example; 4,758,491 relating to dry toner and developer compositions
with a multiphase polyorganosiloxane block or graft condensation
copolymer, which provides polyorganosiloxane domains of a particular size
and concentration at the toner particle surfaces; and 4,820,604 directed to
toner compositions comprised of resin, pigment particles, and a sulfur
containing organopolysiloxane wax, such as those of the formulas
illustrated in the Abstract of the Disclosure.
There are disclosed in U.S. Patent 4,307,169 microcapsular
electrostatic marking particles containing a pressure fixable core, and an
encapsulating substance comprised of a pressure ruptùrable shell, wherein
the shell is formed by an interfacial polymerization. One shell prepared in
accordance with the teachings of this patent is a polyamide obtained by
interfacial polymerization. Furthermore, there is disclosed in U.S. Patent
4,407,922 pressure sensitive toner compositions comprised of a blend of
two immiscible polymers selected from the group consisting of certain
polymers as a hard component, and polyoctyldecylvinylether-co-maleic
anhydride as a soft component. Interfacial polymerization processes are
also selected for the preparation of the toners of this patent. A!so, there is
disclosed in the prior art encapsulated toner compositions containing in
some instances costly pigments and dyes, reference for example the color
photocapsule toners of U.S. Patents 4,399,209; 4,482,624; 4,483,912 and
4,397,483.
~or-ov r, lllu-tr~t-d ln U 8 P~t-nt 4,758,506 r lngl- co~pon nt
cold pressure fixable toner composition-, wherein the shell
selected can be prepared by an interfacial polymerization
process .
Disclosed in copending application U s Patent No
s,045,422, issued September 3, 1991, entitled Encapsulated Toner
Compositions are encapsulated compositions containing coros
comprisQd of a fluorocarbon-incorporatQd rQsin binder More
specifically, there is illustrated in the aforemontioned patent
an encapsulated toner composition comprisQd of a core with a
fluorocarbon-incorporated re-in binder, pigment or dyes, and a
polymeric shell; and an encapsulatQd toner composition comprised
of a cor~ comprised of a fluorocarbon-incorporated resin binder
derived from the copolymerization of an addition-type monomer and
a functionalized fluorocarbon compound representQd by Formula
(I), wherein a is a structural moiety containing an addition
polymQrization functional group; B is a fluorine atom or a
structural moiety containing an addition polymerization
functional group and x i- the number of difluoromethylene
functions, pigment or dyes, and a polymeric shell Also,
illustrated in U S Patent No 5,013,630, issued May 7, 1991,
entitled Encap-ulated Toner Compositions is an encapsulated toner
composition comprised of a core comprised of pigments or dyes,
and a polysiloxane-incorporated core binder resin, which core is
Qncapsulated in a polymeric shell Moreover, illustrated in U S
Patent No 5,023,159 i~ued June 11, 1991, ncapsulated tonQrs
with a ~oft core co~prised of silane modified polymer resin, a
colorant, and a polymeric shell thereover Specifically, in one
embodi~ent there i- di-closed in the aforementioned patent
encap~ulat-d toner- co~prised of a core containing a silanQ-
modified polymer resin, preferably obtained by free radical
poly erization, silane-modified pigment particles or dyes, and
thereover a shell preferably obtained by interfacial
polymerization U S Patent 5,023,159, in one embodiment is
directed to an encapsulated toner composition comprised of a core
comprised of a polymer product of a monomer or monomers, and a
polyfunctional organosilicon reagent, and
'- 2~4194~
more specifically wherein the core is comprised of a silane-modified
polymer resin having incorporated therein an oxysilyl (I), a dioxysilyl (II), ora trioxysilyl (m) function of the following formula, pigment dye particles or
mixtures thereof; and a polymeric shell.
O-- O--
`. Si-O-- Si-O-- Si-O--
.. I l I
:~, O--
~, (I) (Il) (III)
The aforementioned toners can be prepared by a number of
different processes including the interfacial/free-radical polymerization
process which comprises (1) mixing or blending of a core monomer or
monomers, up to 10 in some embodiments, a functionalized organosilane,
' a free radical initiator or initiators, pigment, and a shell monomer or
monomers; (2) dispersing the resulting mixture of pigmented organic
materials by high shear blending into stabilized microdroplets in an
aqueous medium with the assistance of suitable dispersants or emulsifying
agents; (3) thereafter subjecting the aforementioned stabilized
microdroplets to a shell forming interfacial polycondensation; and (4)
subsequently forming the core resin binder by heat induced free radical
polymerization within the newly formed microcapsules. The shell forming
interfacial polycondensation is generally accomplished at ambient
- ` temperature, but elevated temperatures may also be employed depending
-- on the nature and functionality of the shell monomer selected. For the core
polymer resin forming free-radical polymerization, it is generally effected
- at a temperature of from ambient temperature to about 100C, and
preferably from ambient or room temperature, about 25C temperature to
about 85C. In addition, more than one initiator may be utilized to enhance
, .
,,
...
11
2~9~
the polymerization conversion, and to generate the desired molecular
weight and molecular weight distribution.
Accordingly, there is a need for encapsulated toner compositions
with many of the advantages illustrated herein. More specifically, there is a
need for colored encapsulated toners wherein image of brilliant color
quality and excellent resolution can be obtained. Also, there is a need for
pressure fixable magnetic colored encapsulated toners which provide high
quality colored images with excellent image fix levels, for example over 70
percent at low fixing pressure of, for example, 2,000 psi. Moreover, there is
a need for colored encapsulated toners that can be selected for inductive
single component development processes such as those utilized in the
commercial Delphax printers. There is also a need for a conductive
magnetic colored encapsulated toner which is suitable for highlight color
imaging processes. Additionally, there is a need for magnetic colored
encapsulated toners, wherein the cores are comprised of certain magnetic
materials that minimize, or avoid interference with the color quality of the
colorants. Furthermore, there is a need for colored encapsulated toners,
which possess excellent toner physical properties such as no toner
agglomeration, and long shelf life exceeding, for example, 12 months.
There is also a need for magnetic colored encapsulated toners which can be
utilized in the Delphax based ionographic imaging members without or
minimization of the problems of image ghosting and toner agglomeration
in the developer housing. Also, there is a need for magnetic colored
encapsulated toners that have been surface treated with conductive
additives such as conductive metal oxide powders and the like to impart to
their surface certain conductive characteristics, such as a toner volume
resistivity of from about 103 ohm-cm to about 108 ohm-cm. Furthermore,
there is also a need for simple and economic processes for the preparation
of pressure fixable, conductive magnetic colored encapsulated toners.
Specifically, there is a need for interfacial/free radical polymerization
processes for magnetic colored encapsulated toner compositions wherein
explosion prone organic solvents are eliminated in some embodiments.
Moreover, there is a need for a process that provides enhanced flexibility in
- 12 -
the de~ign of the shell and core ~aterial~ for pre~sure
fixable m~gnetic colored encap~ulated toner~, and
flexibility in controlling the toner physical properties
~uch ~ ~urface oonductivity, bulk den~ity, particle
size, and oize dispersity.
~ SUMMARY OF THE INVENTION
`~ It i9 an ob~ect of an aspect of the present
invention to provide eneapsulated toner compositions
with many of the advantages illustrated herein.
;; An ob~eet of an aspeet of the present invention i8
to provide eolored, xeluding black, eneapsulated toner
compositions comprised Or a core comprised of a polymer
resin, or a plurality of polymer resins preferably
obtained by free radical polymerication, colored
pigments and/or dyes, a colorless or lightly colored
powdered iron, cobalt, nickel, magnQsium, manganese,
zinc, and alloys and oxides thereof, and the like, which
possess a high saturation magnetic moment, and a
whitener powder comprisQd of white inorganic material;
and thereover a poly~erie shell prepared, for example,
by interfaeial polymerization and wherein the shell may
have incorporated therein a polyether or silane moiety,
and wherein the toner's surfaee is coatQd with a layer
of conduetive agent.
An ob~ective of an aspect of the present invention
is the provi~ion of eolored eneapsulated toner
composition- which are suitable for the inductive single
componQnt developm nt systQms, such as the Delphax
.J~ 30 apparatuses-
- An ob~ect of an aspQct of the present invention is
the provi~ion of pressure fixable colored encapsulated
toner~ which can be selected for use in transfix
ionographic i~aging systQms wherein image ghosting is
eliminated in 80me ~mbodiment~, or minimizQd in other
embodi~ent~.
.;
. . .
.
,R!,
~ _ ., _ ~
.~
An ob~ect of an aspect of the present invention is
the provision of colored encapsulated toners which
possess excellent thormal and mochanical stability, and
wherein the problem of toner agglomeration i8
eliminated.
An ob~ect of an aspQct of the present invention i8
the provision of pressure fixable magnetic colored
encapsulated toners that can be selected for highlight
color proces6Qs and where$n images of i~proved color
quality are obtained as compared to a~number of known
pressure fixable magnetic colored toners.
an ob~ect of an aspect of the present invention is
the provision of colored encapsulated toners wherein
core component leaching or 1088 is eliminated in some
~bodiments, or minimized in other Qmbodiments.
An object of an aspect of the prQsent invention is
the provision of color-d encapsulatQd toners wherein
image offsetting is elimianted in some Qmbodiments, or
minimized in other embodiments.
An ob~ect of an aspect of the present invention is
the provision of colored encapsulated toners with
extended ~helf life.
An ob~ect of an aspect of the present invention is
the provision of colored encapsulated toners with
excellent release properties.
An ob~ect of an aspect of the present invention i~
the provision of colored encapsulated toners with a core
containing an iron powder which i8 available from BASF,
and is commercially known as Sicopur 4068 iron powder.
;~ It is an ob~ect of an aspect of the present
invention to provide colored encapsulatQd toner~ wherein
contamination of the imaging member, such as a
dielectric receiver or a photoreceptor, is eliminated or
minimized.
A
:
.
An ob~ect of an aspect of the present invention is
the provi~ion of encapsulated toners that can be
selected for colored imaging processes, especially
highlight color processes, wherein cold pre~sure fixing
is selected.
An ob~ect of an aspect of the present invention is
to provide simple and economical processes for magnetic
eolored encap~ulated toner compo~itions prepared by an
interfacial/free radical polymerization process in which
the shell is generated by interfacial polymerization,
and the core resin is formed by free radical
polymerization.
-~ An ob~ect of an aspect of the present invention
resides in the provision of pre~sure fixable colored
encapsulated toner compositions which provide a high
image fix level of, for example, over 70 percent at a
relatively low fixing pressure of, for example, 2,000
psi.
An objective of an aspect of the present invention
i8 to provide eolored eneap~ulated toner eompositions
whieh are ~uitable for duplex imaging applications.
A feature of an aspeet of the present invention is
to provide colored encapsulated toners whieh eontain a
colorless iron oxide magnetite which has been treated
with an iron carbonyl.
A feature of an aspeet of the present invention is
- to provide eolored eneapsulated toners with average
- particle diameters of from 10 to about 17 microns.
A feature of an aspect of the pre~ent invention is
to provide colored encapsulated toner~ with pigments,
such as PV Fast Blue, Helogen Blue, Sudan Blue, Neopen
Blue, Lithol Searlet, Fanal Pink, Hostperm Pink,
Novaperm Yellow, Sieo Yellow, Helogen Green, and the
like.
..
,~.
- k
.
,
- 14a -
Other aspects of thi~ invention are as follows:
An encapsulated toner composition comprised of a
core comprised o~ a polymer re~in, color pigment, dye or
mixtures thereof, a colorless magnetic material, and a
whitening agent; which core i~ encap~ulated in a
polymeric shell.
An encapsulated toner composition comprised of a
core compri~ed of a polymer re~in, color pigment, dye or
mixtures thereof, a light colored magnetic material, and
a whitening agent; which core is encapsulated in a
polymeric shell.
An encapsulated toner composition comprised of a
core comprised of a polymer resin, color pigment, dye or
mixtures thereof, a colorles~ or lightly colored
magnetic material, and a whitening agent; which core is
encapsulated in a polymeric shell and wherein the shell
has optionally incorporated therein or thereon surface
additives.
An encapsulated toner composition comprised of a
core comprised of a polymer resin, color pigment, a
substantially colorless magnetic m~terial, and a
whitening agent, which core is encapsulated in a
polymeric shell.
An encapsulated toner composition comprised of a
core comprised of a polymer resin, color pigment, a
substantially colorless magnetic material, and an
inorganic powder whitening agent, which core is
encapsulated in a polymeric shell.
A colored magnetic encapsulated toner composition
comprised of a core comprised of a polymer resin, color
; pigment, dye or mixtures thereof, a lightly colored
magnstic material, and a whitening agent of inorganic
powder, which core is encapsulated in a polymeric shell,
and wherein the shell has optionally incorporated on the
~; shell surface or within the shell polymer a conductive
powder, and a release agent.
~'
. ,:
-14b -
An inductive single component colored encapsulated
toner composition compri~ed of a core comprised of a
polymer resin or a plurality of polymer resins, color
pigment, dye or mixture~ thereof, a colorless or lightly
colored magnetic material of high magnetic saturation
moment and a whitening agent, which core iB encapgulated
in a polymeric shell obtained by interfacial
polymerization, and wherein the toner i~ optionally
rendered conductive by application to the toner's
surface of a layer of conductive powder.
A colored magnetic encapsulated toner composition
comprised of a core comprised of a polymer resin,
colored pigment, excluding black, lightly colored
magnetic material and an inorganic whitener, which core
is encapsulated in a polymeric shell which contains
polyether or siloxane moieties as integral parts of its
polymer structure, and wherein the toner is optionally
coated with a layer of conductive and release agents.
An imaging method which comprises the formation of
an image on an imaging substrate, subsequently
developing the image with the toner composition referred
to hereinbefore, and transferring the image to a
substrate.
A method which comprises the formation of an image
on a di-lectric substrate, ~ubseguently developing the
image with the toner composition ~et out hereinbefore,
and transferring the image to the substrate.
A process for the preparation of encapsulated
toners of the type hereinbefore set out which comprises
mixing a core monomer, or a plurality of monomers, a
- free radical initiator, a colorant, a whitener, a
~ substantially colorless magnetic material and an oil
- soluble shell monomer, or plurality of monomers;
dispersing the resulting mixture by heat shear blending
into stabilized microdroplets in an aguoous medium;
~" sub~Qcting the aforementioned stabilized droplets to a
~, .,
. ,
- 14c -
shall forming interfacial polycondensation; subsequently
forming the core re~in binder by heat induced free
radical polymerization; and optically subjecting the
S resulting encapsulated toner particles to washing and
drying.
An encapsulated toner composition comprised of a
core comprised of a polymer resin, color pigment,
excluding black, a lightly colored magnetic material,
and a whitening agent.
An encapsulated toner composition comprised of a
core comprised of polymer resin particles, color pigment
particles, colorless or lightly colored magnetic
material particles, and whitening agent particles, and
which core is encapsulated in a polymeric shell, and
wherein the shell has optionally incorporated therein on
the shell surface or within the shell polymer functional
additives comprised of conductive components and release
agents.
A highlight colored encapsulated toner comprised of
a core comprised of a polymer resin, color pigment,
excluding black, a substantially colorl-ss or lightly
colored magnetic material, and a whitening agent.
By way of added explanation, the foregoing and
other objects and features of the present invention can
be accomplished in embodiments thereof by the provision
of toners and more specifically encapsulated toners. In
one ~bodiment Or the present invention, there are
provided color-d encapsulated toners comprised of a core
comprised Or a polymer resin, pigment or dye, a
colorlQss or lightly colored magnetic material of high
magnetic saturation ~om nt of over 70 emu per gram, and
a whitener; and thereover a poly eric shell, which shell
; ~urface can be coated with a layer of conductive powder
such as conductive metal oxide~, and the like.
.
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.
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- 14d -
The present invention in one embodiment is directed
to an encapsulated colored toner composition comprised
of a core comprised of a polymer resin obtained by free
radical polymerization of a monomer or monomer~,
colorant, excluding black colorant, or mixtures of
colorants, and a colorless or lightly colored magnetic
material such as the iron powder, Sicopur 4068 of BASF,
and a whitening agent, and wherQin the eore i8
encapsulated in a polymeric shell preferably obtained by
interfacial polymerization, and wherein the toner is
rendered conduetive with a layer of surfaee eonduetive
additives sueh as a eonductive powder eomprised of very
fine eonduetive metal oxides of tin, titanium, silicon,
and the li~e. The
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shell of the toner composition of the present invention may have
incorporated therein a polyether moiety or an oxysilyl (I), a dioxysilyl (II), or
a trioxysilyl (m) function of the following formula
O-- O--
Si-O-- Si-O-- Si-O--
O--
(I) ~II) (III)
The aforementioned toners of the present invention can be
prepared by a number of different processes including the interfacial /free
radical polymerization processwhich comprises (1) mixing or blending of a
core monomer or monomers, up to 10 in some embodiments, a free radical
initiator or initiators, colorant, a colorless or lightly colored magnetic
material such as the iron powder, Sicopur 4068 of BASF, a whitener such as
powdered calcium carbonate, tin oxide, titanium oxide, zinc oxide, zinc
stereate or the like, and an oil-soluble shell monomer or monomers; (2)
dispersing the resulting mixture by high shear blending into stabilized
microdroplets in an aqueous medium with the assistance of suitable
dispersants or emulsifying agents; (3) thereafter subjecting the
aforementioned stabilized microdroplets to a shell forming interfacial
polycondensation by adding a water soluble shell monomer which reacts
with the oil soluble shell monomer at the microdroplet water interface; (4)
subsequently forming the core resin binder by heat induced free radical
polymerization within the newly formed microcapsules; (5) subjecting the
resultant encapsulated particles to washing and drying; and (6) optionally
coating the encapsulated particles with surface release and conductive
powder by dry blended process to provide a volume resistivity in the range
of 103 to 108 ohm-cm, for example. The shell forming interfacial
polycondensation is generally accomplished at ambient temperature, but
,
.
-16- ~l)41~0
elevated temperatures may also be employed depending on the nature and
functionality of the shell monomer selected. For the core polymer resin
forming free radical polymerization, it is generally effected at a
temperature of from ambient temperature to about 100C, and preferably
from ambient or room temperature, about 25C temperature to about
90C. In addition, more than one initiator may be utilized to enhance the
polymerization conversion, and to generate the desired molecular weight
and molecular weight distribution.
Further, in accordance with the present invention there are
provided processes for pressure fixable colored encapsulated toner
compositions which are obtained without using organic solvents as the
diluting vehicles or as reaction media. These processes involve dispersing a
mixture of organic materials, colorants and magnetic material to form
stabilized microdroplets in an aqueous medium containing a dispersant or
emulsifying agent. The above-mentioned mixture is comprised of from
about 20 to about 90 weight percent of core monomer or monomers, about
1 to 20 weight percent of a colorant or colorants, from about 30 to about
60 weight percent of a colorless or lightly colored magnetic material, and a
whitener such as an inorganic oxide powder of from about 1 to about 25
weigth percent, and a shell forming monamer component of from about 2
to 25 weight percent, and a free radical initiator. The shell formation
around the dispersed, stabilized microdroplets via interfacial
polycondensation is initiated by adding to the reaction mixtures a water
soluble shell forming monomer component. Subsequently, the reaction
mixture is subjected to heating to initiate free radical polymerization to
form the desired core polymer resin within the newly formed
microcapsules. The encapsulated particles produced are washed with
water, dried, and dry blended with surface additives comprised of
conductive and release agents. In general, about 0.1 to about 15 weight
percent of conductive agent in the form of very fine powder is employed,
while from about 0 to about 10 weight percent of surface release agent is
utilized. In one specific embodiment, the toner of the present invention
can be rendered insulative without the application of the surface
,~''
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-17- ~41940
conductive coating, and which toner can be selected for use in xerographic
development wherein image toning and transfer are accomplished
electrostatically, and image fixing is achieved in a separate step with a
pressure roll.
Examples of core monomers present in effective amounts, for
example from about 20 to about 90 weight percent, include, but are not
limited to, styrenes, methacrylates, acrylates, the copolymeric derivatives
thereof, mixtures thereof and the like; and more specifically, addition
monomers that can be selected as the core monomers of the present
invention include, methyl acrylate, methyl methacrylate, propyl acrylate,
propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate,
pentyl acrylate, pentyl methacrylate, hexyl acrylate, hexyl methacrylate,
cyclohexyl acrylate, cyclohexyl methacrylate, lauryl acrylate, lauryl
methacrylate, stearyl acrylate, stearyl methacrylate, benzyl acrylate, benzyl
methacrylate, ethoxypropyl acrylate, ethoxypropyl methacrylate,heptyl
acrylate, heptyl methacrylate, isobutyl acrylate, isobutyl methacrylate,
methylbutyl acrylate, methylbutyl methacrylate, tolyl acrylate, tolyl
methacrylate, styrene, dodecyl styrene, hexyl methyl styrene, nonyl styrene,
tetradecyl styrene, other substantially equivalent addition monomers, and
the like.
As colored pigments present in an effective amount such as, for
example, from about 1 to about 20 weight percent, and preferably from
- about 3 to about 10 weight percent, there can be selected PV fast blue
available from Hoescht Corporation, Helogen Blue available from BASF,
Sudan Blue, Lithol Scralet available from BASF, Fanal Pink, Hostaperm Pink,
Novaperm Yellow, Sico Yellow, Luna Yellow, Helogen 6reen, Levanox
Green, Bayplast Green, Sicopal Brown, Heliogen Blue L6900, D6840, D7080,
D7020, Pylam Oil 81ue and Pylam Oil Yellow, Pigment 81ue 1 available from
Paul Uhlich & Company Inc., Pigment Violet 1, Pigment Red 48, Lemon
Chrome Yellow DCC 1026, E.D. Toluidine Red and 8On Red C available from
Dominion Color Corporation Ltd., Toronto, Ontario, NOVAperm Yellow
FGL, Hostaperm Pink E from Hoechst, Cinquasia Magenta available from E.l.
DuPont de Nemours 1~ Company, and the like. Illiustrative examples of
~' .
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-18 'f~1 9'~
primary colorants (cyan, magenta, yellow) that can be selected include the
magenta colorants such as, for example, 2,9-dimethyl-substituted
quinacridone and anthraquinone dye identified in the Color Index as Cl
60710, Cl Dispersed Red 15, diazo dye identified in the Color Index as Cl
26050, Cl Solvent Red 19, and the like; the cyan colorants such as copper
tetra-(octadecyl sulfonamido) phthalocyanine, x-copper phthalocyanine
pigment listed in the Color Index as Cl 74160, Cl Pigment Blue, and
Anthrathrene Blue identified in the Color Index as Cl 69810, Special Blue X-
2137, and the like; and the yellow colorants such as diarylide yellow 3,3-
dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the
Color Index as Cl 12700, Cl Solvent Yellow 16, a nitrophenyl amine
sulfonamide identified in the Color Index as Foron Yellow SE/GLN, Cl
Dispersed Yellow 33 2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-
2,5-dimethoxy acetoacetanilide, and Permanent Yellow FGL.
As the magnetic material, there is selected in an effective
amount, such as, for example, from about 20 to about 60, and preferably
from about 30 to about 50 weight percent, a colorless or lightly colored
magnetic material which does not significantly interfere with the
coloration of the colorants. Illistrative examples of colorless or lightly
colored magnetic materials that can be selected include iron powder,
Sicopur 4068 of BASF; Magnox's brown magnetite, TMB-50; brown iron
oxide, LODOMS; ferrites of magnesium; nickel, magnesium, manganese,
zinc and alloys and oxides thereof, and the like. One preferred magnetic
material for the encapsulated toner composition of the present invention is
Sicopur 4068 iron powder, which has the following characteristics as
reported by BASF, (1) high magnetic saturation moment of about 98 emu
per gram; (2) particle size of about 2 to about 6 micron in average particle
diameter; (3) grayish in color; and (4) particle shape ranging from being
spherical to elliptical to acicular. Typical whitening agents are white
inorganic oxides such as oxides of tin and titanium, and the like with the
amount of the whitening agent being, for example, in the range of, for
example, from about 1 to about 30 weight percent, and preferably from S
to 20 weight percent.
:
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-19-
Examples of shell polymers present in various effective amounts
such as, for example, from about S to about 25 weight percent include
polyureas, polyamides, polyesters, polyurethanes, mixtures thereof, and
other similar polycondensation products including the reaction products of
polyether polyisocyan~te pr~po~ rs with polyamine~,
reference u.s. P~tent No. 5,043,240, ~s~ued August 27,
199l; the r-~ction product~ of poly~iocyanate~ with
functionalized organosilanes ~nd polyamines, reference
u.s. P~t~nt No. 5,104,763, is~ued April 14, 1992 with
poly~in~s. Th~ sh~ll amounts are generally from
about 5 to about 25 weight percent of toner, and have a thickness
generally, for example, of less than about 5 microns, and more specifically
from about 0.1 micron to about 3 microns in an embodiment of the present
invention. Other shell polymers, shell amounts, and thicknesses may be
selected. The polymeric shells are usually prepared by interfacial
polymerization processes such as those illustrated in U.S. Patents 4,000,087;
4,307,169 and 3,429,827.
The oil soluble shell forming monomer components present in
the microdroplet phase are in embodiments comprised of diisocyanates,
diacyl chloride, bischloroformate, together with appropriate
polyfunctional crosslinking agents such as triisocyanate, triacyl chloride,
and the like. Illustrative examples of the oil soluble shell monomer
components include benzene` diisocyanate, toluene diisocyanate,
diphenylmethane diisocyanate, cyclohexane diisocyanate, hexane
diisocyanate, Uniroyal Chemical's diphenylmethane diisocyanate-based
liquid polyether Vibrathanes such as B-635, B-843, and toluene
diisocyanate-based liquid polyether Vibrathanes such as B-604, B-614,
Mobay Chemical Corporation's liquid polyether isocyanate prepolymers,
DESMODUR E-21, E-21A, 744, AMODUR CB-60, MONDUR CB-75, MONDUR
MR, MONDUR MRS 10, adipoyl chloride, fumaryl chloride, suberoyl
chloride, succinyl chloride, phthaloyl chloride, isophthaloyl chloride,
terephthaloyl chloride, ethyiene glycol bischloroformate, diethylene glycol
, .
-20- ~41940
bischloroformate, mixtures thereof, and the like. The water soluble, shell
forming monomer components which are added to the aqueous phase can
be a polyamine or polyol including bisphenols, the nature of which is
dependent on the shell characteristics desired, for example. Illustrative
examples of water soluble shell monomers that react with the
aforementioned diisocyanates, and the like include ethylenediamine,
triethylenediamine, diaminotoluene, diaminopyridine,
bis(aminopropyl)piperazine, mixtures of polyamines and
aminoalklyltrialkoxy silane, aminoalkylalkyldialkoxy silane,
aminoalkyldialkylalkoxy silane, p-aminoaryltrialkoxy silane,
N-(aminoalkyl)aminoalkylalkyldialkoxy silane,
N-(aminoalkyl)aminoalkyltrialkoxy silane,
3-[bis(hydroxyalkyl)aminolalkyltrialkoxy silane,
trialkoxysilylal kyldialkylenetriami ne,
1,3-bis(hydroxyalkyl)tetraalkyldisiloxane, or the like, bisphenol A,
bisphenol Z, and the like. When desired, a water soluble crosslinking
component such as triamine or triol can also be added to improve the
mechanical strength of the shell structure.
In one embodiment of the present invention, there is provided a
process for the preparation of improved encapsulated toner compositions,
which process comprises mixing and dispersing a core monomer or
monomers, a free radical initiator or initiators, colored, excluding black,
pigment particles or dyes, a colorless or lightly colored magnetic material as
illustrated herein, a whitener, an oil soluble shell monomer component,
into microdroplets of specific droplet size and size distribution in an
aqueous medium containing a dispersant or stabilizer wherein the volume
average diameter of the microdroplet can be adjusted to be preferably
from about 5 microns to about 30 microns, and its volume average droplet
size dispersity can be controlled to be preferably less than about 1.4, as
determined from Coulter Counter measurements of the microcapsule
particles after encapsulation; forming a microcapsule shell around the
microdroplets via interfacial polymerization by adding a water soluble shell
forming monomer component; affecting a free radical polymerization to
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-21-
form a core resin binder within the newly formed microcapsules by, for
example, heating the reaction mixture from room temperature to about
100C for a period of from about 1 to about 10 hours; and subsequently
washing and drying the resultant encapsulated particles. Stabilizers
selected for the process of the present invention include water soluble
polymers such as poly(vinyl alcohols), methyl cellulose, hydroxypropyl
cellulose and the like. Illustrative examples of free radical initiators
selected for the preparation of the toners of the present invention include
azo compounds such as 2-2'-azodimethylvaleronitrile, 2-2'-
azoisobutyronitrile, azobiscyclohexane-nitrile, 2-methylbutyronitrile or
mixtures thereof with the quantity of initiator(s) being, for example, from
about 0.01 percent to about 10 percent by weight of that of core
monomer(s). Interfacial polymerization processes selected for toner shell
formation and shells thereof are as illustrated, for example, in U.S. Patents
4,000,087 and 4,307,169.
The toner compositions can be rendered conductive by
conventional dry blending process with a suitable conductive powder in an
effective amount of from about 0.1 to about 15 weight percent. In general,
a volume resistivity of about 103 to 108 ohm-cm, preferably from about 104
to 107 ohm-cm, is desired for the Delphax based ionographic transfix
development. Illustrative examples of conductive reagents include metal
halides such as copper iodide, and potasium iodide, conductive powdered
oxides and mixed oxides of aluminum, barium, chromium, germanium,
indium, magnesium, molybdenum, nickel, silicon, titanium, tin, zirconium,
and a combination of two or more of these metals, and the like, and
wherein tho speciric resistivity Or the powder is less
than 100 ohm-c , and preferably less than 50 ohm-cm.
Specific exa~ples of co ercial conductive powders that
can be selQcted for the compositions of the present
invention include conductive powders available from
Magnesium Electron Inc., ~itsubishi, Sumimoto Cement
Company, and Tioxide a~ electroconducting powder T-l
(Mitsubi~hi), the tin/antimony oxides KW175 (Magnesium
Electron Inc.), the coated titanium oxide, electroconducting
~ .
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powder W-1 and W-10 (Mitsubishi), KW375 (Magnesium Electron Inc.),
electroconducting white pigments (Tioxide), electroconducting pigments
(Sumimoto Cement Company). Surface release andtor flow agents may also
be used to provide the release and flow properties to the toner. Illustrative
examples of these agents that can be selected for the toner compositions of
the present invention include, for example, metal salts, metal salts of fatty
acids, colloidal silicas, mixtures thereof, and the like, which additives are
usually present on the surface of the toner in an amount of from about 0.1
to about S weight percent, reference U.S. Patents 3,590,000; 3,720,617;
3,655,374 and 3,983,045. Preforred ~dditives include
zinc stearate, magnesium stearate, and A~rosil R972.~
The following examples are being submitted to further define
various aspects of the present invention. These examples are intended to
be illustrative only and are not intended to limit the scope of the present
invention.
~ ,
EXAMPLEI
The following example illustrates the preparation of a 17.1
micron red encapsulated toner using Sicopur 4068 iron powder and a
conductive tin oxide agent. This pressure fixable encapsulated toner is
suitable for inductive single component development.
A mixture of n-lauryl methacrylate (113.0 grams), Isonate 143 L
(42.0 grams), Desmodur E-21 (5.7 grams), Vazo 52 (1.6 grams), Vazo 64 (1.6
grams) was homogenized at 4,000 rpm using an IKA T-50 polytron with a
G45/M probe for 30 seconds. To this mixture were added titanium dioxide
powder (rutile form, 90 grams), Sicopur 4068 iron powder (245.0 grams)
and Lithol Scarlet pigment (29.0 grams), followed by homogenization at
8,000 rpm for 3 to 5 minutes. To the resulting slurry was then added one
liter of a 0.10 percent aqueous poly(vinylalcohol) solution, and the mixture
was then homogenized at 9,000 rpm for 2 minutes. The resulting
dispersion was transferred into a two liter kettle equipped with a
mechanical stirrer. Bis(3-aminopropyl)piperazine (33.0 grams) was added,
" .
-23- ~V~1~40
and the mixture was stirred for one hour at room temperature.
Subsequently, the reaction mixture was heated in an oil bath with the
temperature of the bath being raised from ambient temperature to 90C
over a period of 45 minutes, and then held at this temperature for another
6 hours. After cooling to room temperature, the mixture was allowed to
remain at room temperature to permit the encapsulated particles to settle
to the bottom of the reaction kettle. The separated particles were washed
repeatedly with water until the aqueous phase was clear. The wet
encapsulated particles were sieved through a 180 micron screen, and freeze
dried to provide 350.0 grams of red encapsulated particles.
A mixture of 120.0 grams of the above prepared red
encapsulated particles and 3.0 grams of conductive tin oxide doped with
antimony oxide powder (volume resistivity of 1 to S ohm-cm, available from
Mitsubishi as ECP T-1) was dry blended in a dry blender at 3,000 rpm for 4
minutes. The blending was continued for another 15 minutes with an
additional 6.0 grams of the above ECP T-1 conductive powder, and then
with 1.2 grams of zinc stearate for 1 minute, followed by sieving through a
63 micron screen. The resulting red encapsulated toner product has a
volume average particle diameter of 17.1 microns and a particle size
distribution of 1.34 as obtained using the Coulter Counter Model ZM,
available from Coulter Electronics, Inc.
The toner's volume resistivity was measured on powdered
samples, which were packed in a 1 cm3 cell using a horseshoe magnet
placed beneath the cell. Two opposite walls of the cell are 1 centimeter x 1
centimeter conductive metal plates. The other walls and the bottom of the
cell are 1 centimeter x 1 centimeter, and are comprised of an insulating
material. A voltage of 10 volts is applied across the plates, and the current
flow through the plates is measured using an electrometer. The device is
standardized using a nickel standard whose saturation magnetic moment is
known (55 emu/gram). The nickel sample is magnetized between two
magnetic pole hces with a saturating magnetic field of 2,000 Gauss, such
that the induced magnetic field is perpendicular to one of the 1 centimeter
faces of the cell. The integrated current that is induced when the nickel
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-24-
~041~0
sample is removed from the saturating magnetic field is measured. Next,
the integrated current induced by a toner sample under identical
conditions is also measured. The toner's saturation magnetic moment is
then obtained by referencing its induced current per gram of sample to
that of the nickel sample. For the toner of this example, the saturation
magnetic moment was measured to be 49 emu per gram, and its volume
resistivity was measured to be 7.1 X 107 ohm-cm.
The above prepared toner was evaluated in a Xerox Corporation
4060'~ printer. The images developed were transfixed onto paper with a
transfix pressure of 2,000 psi. Print quality was evaluated from a
checkerboard print pattern. The image optical density was measured with
a standard integrating densitometer. Image fix was measured by the
standardized tape pull method, and is expressed as a percentage of the
retained image optical density after the tape test relative to the original
image optical density. Image smearing was evaluated qualitatively by hand
rubbing the fused checkerboard print using a blank paper under an applied
force for a specific cycle time, and viewing the surface cleanliness of
nonprinted and printed areas of the page. Image ghosting was evaluated
visually. For the above prepared toner, the image fix level was 85 percent,
and no image smear and no image ghosting were observed in this machine
testing. The toner displayed a resistance to agglomeration even when
heated at 55C for 48 hours.
EXAMPLE II
The following example describes the preparation of a 18.8
micron pressure fixable blue encapsulated toner using Sicopur 4068 iron
powder and conductive tin oxide agent.
A blue encapsulated toner was prepared in accordance with the
procedure of Example I except that Hostaperm blue pigment (Hoechst) was
employed in place of Lithol Scarlet pigment. The wet encapsulated
particles were sieved through a 180 micron screen, and freeze dried to
provide 320.0 grams of blue encapsulated particles. The dry encapsulated
particles were dry blended according to the procedure of Example I,
:A,
-25- 2~4i~0
yielding a blue encapsulated tonerwith a volume average particle diameter
of 18.8 microns and a particle size distribution of 1.36. The toner's
saturation magnetic moment was measured to be S0 emu per gram, and
the toner volume resistivity was found to be 9.S X 107 ohm-cm.
The above prepared toner was evaluated according to the
procedure of Example I. For this toner, the image fix level was 81 percent,
and no image ghosting and no image smear were observed in this machine
testing. The toner displayed a resistance to agglomeration when heated at
55C for 48 hours.
.
EXAMPLE III
A blue encapsulated toner with a polysiloxane containing
poly(lauryl methacrylate) core resin and Sicopur 4068 iron powder was
prepared as follows:
The toner was prepared in accordance with the procedure of
Example I with the exception that a mixture of 103.0 grams of lauryl
methacrylate and 10.0 grams of methacryloxypropyl terminated
polydimethyl siloxane (viscosity, 1,500 to 2,500 centistokes) was employed
in place of 113.0 grams of lauryl methacrylate. In addition, 25.0 grams of
Heliogen blue pigment (BASF) was utilized instead of 29.0 grams of Lithol
Scarlet pigment. The encapsulated particles were dry blended with zinc
stearate and conductive powdered tin oxide doped with antimony oxide,
affording a blue encapsulated toner with a volume average particle
diameter of 13.2 microns and a particle size distribution of 1.37. The toner's
saturation magnetic moment was measured to be about 42 emu per gram,
and the toner volume resistivity was found to be 6.3 X 107 ohm-cm. For this
toner, the image fix level was 83 percent, and no image smear and no
image ghosting were observed after 2,000 prints. This toner did not
evidence agglomeration on storage for about six months. .
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2041940
EXAMPLE IV
A green encapsulated toner with a poly(lauryl methacrylate)
core resin and Sicopur 4068 iron powder material was prepared in
accordance with the procedure of Example I except that Hostaperm 6reen
pigment ~Hoechst) was utilized in place of Lithol Scarlet pigment. The
green encapsulated toner as obtained in this manner has a volume average
diameter of 14.1 microns and a particle size distribution of 1.37. The toner's
volume resistivity was 1.1 X 107 ohm-cm, and its saturation magnetic
moment was measured to be 48 emu per gram. The toner was evaluated in
accordance with the procedure of Example I, and substantially similar
results were obtained.
`:~
EXAMPLE V
A magenta encapsulated toner with a (lauryl methacrylate-
stearyl methacrylate) copolymeric core resin and Sicopur 4068 iron powder
material was prepared in accordance with the procedure of Example I
except that a mixture of 56.5 grams each of lauryl methacrylate and stearyl
.methacrylate was utilized instead of 113.0 grams of lauryl methacrylate. In
addition, Lithol Scarlet pigment was replaced with Hostaperm Pink
pigment (Hoechst). The magenta toner as obtained in this manner has a
volume average particle diameter of 18.3 microns and a particle size
distribution of 1.33. This toner has a saturation magnetic moment of 49
emu per gram, and a volume resistivity of 2.4 X 107 ohm-cm.
~,This toner provided a tape fix level of 91 percent, and no image
smear and no image ghosting were observed during machine evaluation.
No signs of toner agglomeration were observed with this toner after six
months of storage.
:`
-~` EXAMPLE VI
A brown colored encapsulated toner was prepared in
.;.:accordance with the procedure of Example m using 300 grams of Magnox
iron oxide, TMB-50 and S.0 grams of Microlith brown pigment instead of
Sicopur 4068 iron powder and Heliogen Blue pigment (BASF), respectively.
-27- 20419~0
The resulting encapsulated toner has a volume average particle diameter of
15.3 micron and a particle size distribution of 1.37. The toner has a volume
resistivity of 3.6 X 107 ohm-cm and a saturation magnetic moment of 45
emu per gram. For this toner, the image fix was 79 percent with no signs of
image smear, image ghosting and toner agglomeration.
EXAMPLE VII
The following procedure illustrates the preparation of a 13.8
blue encapsulated toner with a polysiloxane containing core resin and a
silane modified shell.
A mixture of lauryl methacrylate (103.0 grams),
methacryloxypropyl terminated polydimethyl siloxane (10.1 grams;
viscosity, 1,500 to 2,500 centistokes) Isonate 143L (42.0 grams), Desmodur
E-21 (5.7 grams), Vazo 52 (1.6 grams), and Vazo 64 (1.6 grams) was
homogenized at 4,000 rpm using an IKA T-S0 polytron with a G45/M probe
for 30 seconds. To this mixture were added titanium dioxide powder (rutile
form, 90 grams), Sicopur 4068 iron powder (245.0 grams) and Heliogen Blue
pigment (25.0 grams; BASF), followed by homogenization at 8,000 rpm for
3 to S minutes. To the resulting slurry was then added one liter of a 0.10
percent aqueous poly(vinylalcohol) solution, and the mixture was then
homogenized at 9,000 rpm for 2 minutes. The dispersion was transferred
into a two liter reaction kettle, and into this mixture was added bis(3-
aminopropyl)piperazine (30.0 grams). The resulting mixture was stirred at
room temperature for 15 minutes, followed by addition of
3-aminopropyltrimethoxysilane (S.S milliliters). After the addition, the
mixture was allowed to react at room temperature for 1 hour.
Subsequently, the procedure of Example I for the free radical
polymerization and the work up was repeated to yield a blue toner. The
prepared blue toner had a volume average particle diameter of 13.8
microns and a particle size distribution of 1.34. This toner has a saturation
magnetic moment of 43 emu per gram, and a volume resistivity of 7.2 X 107
ohm-cm. The toner was machine tested in the Delphax S6000~ printer, and
substantially similar results were obtained as reported in Example I.
~'
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~4194~
EXAMPLE VIII
A red encapsulated toner was prepared in accordance with the
procedure of Example m using 29.0 grams of Lithol Scarlet pigment instead
of Heliogen Blue pigment (8ASF). The red encapsulated toner product has
a volume average particle diameter of 14.7 microns and a particle size
distribution of 1.34. Its volume resistivity was found to be 7.8 X 107 ohm-cm
and its saturation magnetic moment, 44 emu per gram. The toner was
evaluated in a Delphax S6000~, and substantially similar results were
obtained.
EXAMPLE IX
An orange encapsulated toner was prepared in accordance with
the procedure of Example I using a mixture of 150.0 grams of Sicopur 4068
iron powder, 150.0 grams of titanium dixoide and 29.0 grams of Bayplast
Orange pigrnent (Bayer) in place of a mixture of 245.0 grams of Sicopur
4068 iron powder, 90.0 grams of titanium dioxide powder and 29.0 grams
of Lithol Scarlet pigment. In addition, 0.08 percent of aqueous poly(vinyl
alcohol) solution was utilized instead of 0.10 percent of aqueous poly(vinyl
alcohol) solution. The orange toner product had a volume average particle
diameter of 19.8 micron and a particle size distribution of 1.32. This toner
had a volume resistivity of 2.3 X 107 ohm-cm and a saturation magnetic
moment of 33 emu per gram. The toner was evaluated in a Delphax
S6000~, and substantially similar results were obtained.
E)tAMPLE X
- A yellow encapsulated toner was prepared in accordance with
the procedure of Example IX using Novaperm Yellow pigment (Hoechst)
instead of Bayplast Orange pigment. The yellow toner obtained had a
volume average particle diameter of 18.7 microns and a particle size
distribution of 1.34. The toner had a volume resistivity of 5.1 X 107 ohm-cm
and a saturation magnetic moment of 32 emu per gram. This toner was
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evaluated in a Delphax S6000t", and substantially similar results were
obtained .
Other modifications of the present invention may occur to those
skilled in the art subsequent to a review of the present application, and
these modifications are intended to be included within the scope of the
present invention.
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