CA1174886A - Self-fixing electrographic developer including toner particles comprising a polyester resin and a polyester plasticizer - Google Patents
Self-fixing electrographic developer including toner particles comprising a polyester resin and a polyester plasticizerInfo
- Publication number
- CA1174886A CA1174886A CA000400733A CA400733A CA1174886A CA 1174886 A CA1174886 A CA 1174886A CA 000400733 A CA000400733 A CA 000400733A CA 400733 A CA400733 A CA 400733A CA 1174886 A CA1174886 A CA 1174886A
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- Prior art keywords
- polyester
- developer
- developer according
- poly
- plasticizer
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/12—Developers with toner particles in liquid developer mixtures
- G03G9/13—Developers with toner particles in liquid developer mixtures characterised by polymer components
- G03G9/132—Developers with toner particles in liquid developer mixtures characterised by polymer components obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Liquid Developers In Electrophotography (AREA)
- Developing Agents For Electrophotography (AREA)
Abstract
ABSTRACT
SELF-FIXING LIQUID ELECTROGRAPHIC DEVELOPERS
A liquid electrostatic image developer is disclosed which forms self-fixing images on an electrostatic image-bearing surface which may be the image-forming surface. The developer comprises a plurality of particles composed of a compatible blend of at least one polyester resin and at least one polyester plasticizer. The plasticizer contains essentially no curable groups and is insoluble in the liquid carrier. Furthermore, images from certain preferred developers containing dispersed colorants are crack-resistant in addition to self-fixing.
SELF-FIXING LIQUID ELECTROGRAPHIC DEVELOPERS
A liquid electrostatic image developer is disclosed which forms self-fixing images on an electrostatic image-bearing surface which may be the image-forming surface. The developer comprises a plurality of particles composed of a compatible blend of at least one polyester resin and at least one polyester plasticizer. The plasticizer contains essentially no curable groups and is insoluble in the liquid carrier. Furthermore, images from certain preferred developers containing dispersed colorants are crack-resistant in addition to self-fixing.
Description
~74~386 _l_ SELF-FIXINC LIQUID ELECTROGRAPHIC DEVELOPERS
m e present lnventlon relates to ~elr_ fixing liguid electro~tatlc image de~eloper~ comprising as a dlspersed component, a compatlble blend o~ at least one polyester blnder and at lea~t one polye~ter plastlclzer, to image~ formed ~rom such developer~, and to methods of formlng images with such developers.
Electrographlc imaglng and development processes have been extenslvely described in both the patent and other llterature. Cenerally, these processes have in common the step~ of formlng an electrostatlc charge image, often called an electro-static latent image, on an lnsulatlng sur~ace, such as a photoconductive lnsulating layer coated on a conductive ~upport. m- electrostatic latent image i8 then rendered vl~lble by a development step ln which the charge image_bearing ~urface 18 brought into contact with a suitable electrostatlc image developer compositlon which deposits toner particle on either the charged or uncharged lmage areas. After development, the visible image i8 either heat_flxed dlrectly to the electrostatlc charge_bearing sur~ace or lt 18 transferred to another surface such as paper where lt 18 there heat-~ixed.
Llquid developer compositions of the type de~cribed ln U.8. Patent No. 4,202,785 are very useful for developlng latent electrostatlc images.
m ese developer~ comprl~e a stable dl perslon o~
dlsper~ed componQnts and dl~olved component~ in an electrically ~nsulating carrler ll~uld. The dlspersed component~ include charged p~rtlcle~, ~nown a~ toner partlcle~, comprl~lng ~ colorant or pigment, ~uch a~
carbon black, generally a~ociated wlth a thermo_ plastlc re~ln blnder. The dl~solved component~
_2-include optional organic liquids from previous steps ln the preparation of the liquid developer, as well as optional charge control agents.
Liquid developers containing polyester resin binders such as those disclosed in the afore-mentloned U.S. Patent No. 4,202,785 as well as developers containing other polyester resin binders are particularly useful. As noted in the said U.S. patent, however, the polyesters are fixed to receiving surfaces by the application of heat. Heat_fixable polyesters having very high glass transition temperatures (Tg), (i.e., above 150C) thus require higher fixing temperatures as well as careful selection of the receiving support to avoid support distortion or charring.
In the published patent literature, various llquid toner formulations having self-fixing qualities are reported. For example, U.S. Patent 3,954,640 reports the use of low Tg linear addition polymers to give liquid developers and lnks that become fixed to a substrate with little or no carrier evaporation in the a~sence of heat. It ls essential to this patent that the polymer Tg be no higher than 35C.
m e patent further discloses the use of monomeric plasticizers as optional components that are miscible in the carrier. ~ The purpose of the plasticizer is to ad~ust the ability of the carrier to disperse the polymer resin.
U.K. Patent 1,110,225 describes a liquid developer which is sald to be self_fixing upon removal of the carrier liquid ~ollowing deposition of the toner particles. To achieve such self_fixing, the patent discloses the use of liquid alkyd resins which, because of their unsaturated chemical bond linkages, cure in air upon removal of the carrier liquid. Toner particles containing oxidizing type unsaturated alkyd ~74~386 resins in combination with certain phenol modified pen-taerythritol ester resins are also noted in UK Patent 897,903.
Also from the patent literature, the use of certain plasticizers is reported in liquid toner formu-lations for purposes entirely unrelated to selffixing.
Thus, for example, it is reported that toner adhesion to a substrate can be achieved by tack modification;
that i6, through the addition of modifying agents, a resin binder can be rendered suitably tacky to adhere to a surface of choice. According to Smith et al US
Patent 3,939,085 issued February 17~ 1976, the addition of monomeric plasticizers to toner resins produces a toner composition which has low adhesion for an image-forming surface and high adhesion for a copy surface.The adhesion differential facilitates transfer of toner images from the imageforming surface to the copy where the tacky quality is lost by curing. From the teach-ings of this patent, therefore, it would appear that the use of plasticizers will not produce a toner which self-fixes to an image-forming surface.
US Patent ~,839,032 issued October 1, 1974, relates to the use of carrier-soluble monomeric and polymeric plasticizing agents for the toner binder resin. The use of carrier-soluble plasticizers, how-ever, is undesirable as they tend to le&ch out of the binder resin into the carrier, thus negating any poten-tial benefit from ther use. Furthermore, this document does not teach that its toners are self-fixing.
In &ccordance with the presnet invention, a self-fixing liquid electrographic developer is provided exhibitng, in its broadest aspects, several significant advantages. The developer is self-fixing without resort to tacky low-T binder polymers. The self-fixing property, moreover, is exhibited specifically on an electrostatic image-bearing surface without fear ~L~7~86 of unwanted transfer to other surfaces. Furthermore, the liquid developer exhibi~ its self-fixing property immediately upon extraction o~ the image-bearing surface or element from the liquid development region, in contrast to the prior art methods relying upon further chemical reaction of included curing agents having unsaturated chemical groups.
These and other advantages are achieved with a liquid electrographic developer composition which self-fixes to an electrostatic image-forming surface.
According to the present invention there is provided a liquid electrostatic image developer composition comprising an electrically insulating organic carrier liquid contain~ng, as a dispersed constituent, a plurality of toner particles comprising a compatible blend of at least one polyester resln and at least one polyester plasticizer, characterized in that the plasticizer is substantially free of curable groups and i~ substantially insoluble in the carrier liquid.
Self_fixing in the context of the present invention denotes the quality of forming a rub resistant image on an electrostatic image-bearing surface without resort to externally applied heat.
me self-fixing property, moreover, is substantially immediate, after the image_bearing surface is treated in and removed from the liquid developer, and any residual carrier evaporated to dryness. To determine whether a particular developer meets the sel~-~ixing criteria of the present invention one can employ a simple test to determine rub resistance. The rub test comprise~ the appllcatlon of a 700 gram wei pted olelc acid soaked patch approxlmately 5 mm in diameter to a toner_bearing image and oscillating a portion of the image back and forth underneath the absorbent ~7~386 patch. Oleic acid is chosen to simulate natural finger oil. Rub resistance is determined as a range A to B, wherein A is the number of oscillatory cycles (a cycle being one movement of the patch back and forth) lt takes to first interrupt the toner image integrity while B
represents the number of cycles necessary to completely remove the sub~ected portion of the image by such rubbing. Specific toner images prepared in accordance with the present invention, exhibit an A value of from 1 to 9 cycles and a ~ value of from 2 to 12 cycles whereas control images having no polyester plasticizer are completely removed (B) in one cycle. In the practice of this inventlon, higher A_B values are, of course, likely to be obtained depending on such factors as the materials used in the compatible blend of resin and plasticizer, as well as the nature of the surface to which the blend is self_fixed.
In the practice of the present invention, a compatible blend Or at least one polyester resin and at least one polyester plasticizer is used. The plasticizer i8 specifically free of curable groups, in contrast to prlor art materials such as alkyd resins that rely on further chemlcal reaction of curable groups to fix. The plasticizer, moreover, is substantially insoluble in the carrier liquid 80 as to prevent leaching Or the plasticizer into the carrier~ A
compatible blend in this regard, refers to the ability of the re~in and plasticizer to form a non_hazy solid solution of one in the other.
The ratio of components in the compatible blend varies widely in accordance with the user need~. A useful wei p t ratio of plasticizer to resin is in the range from 0.2 to 1Ø A preferred ratio is in the range from 0.25 to 0.5.
1~74~3~i Many polyester reslns are useful ~n the practice of the present invention. Typical polyesters include repeating diol units and diacid recurring units well known to those skilled in the art.
Representative polyesters are disclosed, for example in U.K. Patent 1,528,950. m is patent discloses a redi~persible liquid developer in which the polyester binder comprises disulphonamido groups.
Preferred polyester resins of the invention include ionic poiyesters comprlsing recurring diol units and recurring ionic diacid units. Representative preferred polyester binders have recurring diol units of the formula:
_ 0 G - 0- _ wherein:
Gl represents straight or branched chain alkylene ha~ing Z to 12 carbon atoms or, ~ubstituted or unsubstituted, cycloalkylene cycloalkylenebis(oxyalkylene) or cycloalkylene-dialkylene; d have up to 35 mole percent (based on the total moles of diacid units) of ionic diacid units of the formula:
t C A C t wherein:
A represents sulphoarylene, sulphoaryloxy-arylene, sulphocyclohexylene, arylsulphonyl_ imino, sulphonylarylene, iminobis(sulphonyl-arylene), sulphoaryloxysulphonylarylene and sulphoaralkylarylene or the alkali metal or ammonlum salts thereof.
~i7~886 5uch preferred polyester resin~ include, for example, the polyester ionomer resins disclosea in U.S. Patent 4,202,785.
In general, useful polyester resin-~ of the present invention have a glass transition temperature ~Tg) of from 40C to 100C. Polyester resins having a Tg in the aforementioned preferred range can be self-fixed to smooth_surfaced dielectric coated receiving elements, as well as ordinary support surfaces, such as photoconductive co~ted paper or film elements, without dif~iculty.
Materials having a Tg above 150C can also be used.
The glass transition temperatures can be determined by conventional methods, such as differential scanning calorimetry (DSC).
Useful polyester re~ins have an inherent viscosity of 0.01 to 0.65, preferably 0.16 to 0.~1.
Polyester resins havlng inherent viscosities in the preferred range are compatible with the preferred charge control agent~, optionally used in the liquid electrographic developers of the present lnvention.
Inherent viscositie~ of the polyesters are measured in a 1:1 by weight solution of phenol:chlorobenzene at 25C at a concentration of 0.25 gram per 100 ml of solution.
The p1asticizers employed in the compatible blend of resin snd plasticizer are chosen from among a variety of commercially availsble polyester pla8ticizerg hsving ~ Tg below -40C, preferably within the range from about -45C to about -70C. In selecting suitable msterial, the criteria of compatibility with the polyester binder is usually first employed to screen potentislly ~i7~386 .
useful materials. From smong these materials that satisfy the compatibility criteria, one then excludes plasticizers having curable chemic~l groups such as oil-modified polyester plasticizers or epoxidized 5 oils. Of the eligible plasticizers, ones are chosen that are insoluble in the electrically insulating carrier liquid as defined below.
~ 1~74~386 _9_ plasticizers, ones are chosen that are insoluble in the electrically insulating carrier liquid as defined below.
Representative useful polyester plasticizers that are insoluble in commonly employed isoparaffinic hydrocarbon carrier liquids such as that sold under the trade mark 'Isopar' G are listed in the following table by Trade Mar~ and commercial source.
TABLE I
Plasticizer Commercial Source 10 'San~icizer' 429 Monsanto Chemical Co.
'Santicizer' 409 Monsanto Chemical Co.
'Paraplex' C_25 Rohm and Haas Co.
'Paraplex' G_41 Rohm and Haas Co.
'Paraplex' G_57 Rohm and Haas Co.
15 'Paraplex' G_31 Rohm and Haas Co.
'Paraplex' G-40 Rohm and Haas Co.
'Eastman' NP_10 Eastman Koda~ Co.
Preferred polyester plasticizers include those sold under the Trade Marks 'Santicizer' 429, 'Paraplex' G_25, 'Paraplex' G_41 and 'Paraplex' G-57.
'Santicizer' 429, typifying the preferred materials, has the following physical properties:
Acidity 4.0 meq/100 gm max Refractive Index at 25C 1.460 to 1.470 Speclflc Gravity 25/25C . 1.080 to 1.110 Density (25C) ca. lbs./gal. 9.1 . Flash point 288C
Fire point 310C
Insoluble ln water at 25C
Tg -56C
1~74~3~6 Preferred polyester plasticizers comprlse repeating alkylene diol units having 2 to 6 carbon ~toms such as diol units derived from ethylene glycol or butylene diol, and repeating aliphatic diacid units having 3 to 10 carbon atoms such ag diacid units derived 11'74886 from malonic acid, succinic acid or adipic acid. A
particularly preferred polyester plasticizer comprises an acetate terminated adipic acid-butylene glycol polyester.
m e polystyrene equivalent molecular weight of the preferred polyester plasticizers rangeæ from 7000 to 9000 as determined by gel permeation chromatography.
The compatible blend of resin and plasticizer defined above is formed in a variety of ways that facilitate the formation of small particles, preferably of submicron size (l.e., 0.01 to 1.0 micron average particle size). A preferred method of forming the blend comprises preparing a concentrated solution of the plasticizer and resin in a common solvent such as 'Solvesso' 100 (the trade mark for an alkylated aromatic having a ma~or aromatic component and a boiling range of from 150_185C sold by Humble Oil & Refining Co., U.S.A.). me concentrated solution ls thereafter mixed with a large excess Or the liquid carrier to precipitate particles of the plasticizer_resin blend in working developer concentration strength~.
The carrier liquid employed according to the present invention is selected from a varlety of materials that satiæfy the plasticizer insolubility criteria. These materlals should be electrically insulating and have a fairly low dielectric constant.
Useful carrier liquids have a dielectric constant of less than 3, and a volume resistivity greater than 101 ohmlcm. Suitable carrier liqulds include halogenated hydrocarbon solvents, for example, fluorinated lower alkanes, such as trichloromono_ fluoromethane and trlchlorotrifluoroethane, having a boiling range typically from 2C to 55C. Other ~ 4 hydrocarbon solvents which are useful include iso-paraffinic hydrocarbons having a boiling range of from 145 to 185 C, such as Isopar G~, or cyclohydrocarbons, such as cyclohexane. Additional S carrier liquids which are useful include polysilox-anes, odorlesæ mineral spirits and octane.
In general, useful working-strength devel-opers of the present invention contain from 0.005 to 5 percent by weight of the plasticizer-resin blend. These developers contain from 99.999 to 90 percent by weight of the liquid carrier vehicle.
Although it is possible to use the liquid developers of the present invention without further addenda, it is often desirable to incorporate such addenda as charge-control agents, waxes and dis-persing agents for the wax or colorants in the developer.
If a colorless image is desired, it i8 unnecessary to add any colorant. For example, the developer may be used to form a colorless hydropho-bic image in a lithographic printing process. In such case, the resultant developer composition con-sists essentially of the liquid carrier behicle and the plasticizer-resin blend particles of the pres-ent invention.
In accordance with a preferred embodimentof the present invention, however, colorants such as carbon black pigments are also included in the liquid developer defined. In this regard, it has been determined that images formed from toners com-prising polyester resin binder and colorants exhibit a tendency to crack in a pattern resembling that of the bed of a dried lake, the so-called adobe pattern. This tendency is significantly reduced and often eliminated with the presently defined blend of resin-plasticizer. Accordingly, the present invention contemplates the use of ~' ~'74~3a6 colorant-containing developers to produce self-fixing and crack-resistant visible images. Useful results are obtained from virtually any of a wide variety of known dyes or pigment materials. Par-ticularly good results are obtained by using vari-ous kinds of carbon black pigments.
A representative list of colorants are found, for example, in Researc _ sclosure, Vol.
109, May, 1973, in an article entitled "Electropho~
tographic Elements, Materials and Processes".
The colorant concentration, when colorant is present, varies widely with a useful concentra-tion range, by weight of the total dispersed con-stituents, being 10 to 90 percent. A preferred concentration range is from 35 to 45 percent.
Waxes and dispersing agents for the wax are also included as optional dispersed components in the present developers. Suitable waxes and dispers-lng agents include those described in Canadian Serial No. 397,476 by Alexandrovich and Upson filed March 3, 1982, which describes liquid electrographic developers comprising an electrically insulating organic carrier liquid containing dispersed con-stituents and dissolved constituents, said dissolved constituents comprising an electrically insulating organic dispersing liquid which forms a solution with said carrier liquid, said dispersed constitu-ents comprising at least one thermoplaætic resin and wax particles, and characterized in that said devel-oper also contains a dispersing agent for said waxparticles which is insoluble in said solution of carrier liquid and dispersing liquid, but soluble in said dispersing liquid alone. Preferably, the wax particles are a polyolefin wax, carnauba wax, an ester wax or an amide wax. The dispersing liquid used with these waxes is preferably an alkylated ~.~7~386 aromatic liquid when the carrier liquid is an iso-paraffinic hydrocarbon.
Optionally, the developers of the present invention include various charge control agent~ to enhance uniform charge polarity on the developer toner particles.
Various charge control agents have been described heretofore in the liquid developer art.
Examples of such charge control agents may be found in U.S. Patent No. 3,788,995 which describes various polymeric charge control agents. Other useful charge control agents include phosphonate materials described in U.S. Patent No. 4,170,56~ and quaternary ammonium polymers descrlbed in U.S. Patent No. 4,229,513.
Various optional non_polymeric charge control agents are also employed such as the metal salts described in U.S. Patent No. 3,417,019. Other charge control agents known in the liquid developer art may also be employed.
A partial listing of preferred representative polymeric charge control agents for use in the present invention includes poly(styrene-co-lauryl methacrylate_ co_sulphoethyl methacrylate), poly(vinyltoluene_co_ lauryl methacrylate-co-lithium methacrylate_co_meth_ acrylic acid), poly(styrene_co_lauryl methacrylate_co_ lithium sulphoethyl methacrylate), poly(~inyltoluene_co_ lauryl methacrylate-co_lithium methacrylate), poly-(styrene-co-lauryl methacrylate_co_lithium methacrylate), poly(t_butylstyrene_co_lauryl methacrylate_co-lithium methacrylate, poly(t_butylstyrene_co_lithium meth_ acrylate), or poly~vinyl toluene_co_lauryl methacrylate-co_methacryloyloxyethyl trimethylammonium p_toluene ~ulphonate).
1~174~386 The amount of charge-control agent used will vary depending upon the particular charge-control agent and its compatibility with the other component6 of the developer. It is uæually desirable to employ an amount of charge-control agent within the range of from 0.01 to 10.0 weight percent based on the total weight of a working-strength liquid developer compo-sition. The charge-control agent may be added in the liquid developer simply by dissolving or dispersing the charge-control agent in the liquid carrier vehicle at the time concentrates of the components are combined with the liquid carrier vehicle to form a working-strength developer.
Various techniques are employed to prepare a working-strength developer comprising the aforemen-tioned plasticizér-binder blend. For example, as disclosed in US Patent 4,202,785 by Hartman issued May 13, 1980, one or more developer concentrates are prepared for each of the developer components (a con-centrate ls a concentrated solution or dispersion ofone or more developer components in a suitable elec-trically insulating liquid vehicle not necessarily the developer carrier liquid). The concentrates are then admixed in a preselected sequence, the admixture slurried with the carrier liquid to dilute the compo-nents, and the slurry homogenized to form the working-strength developer.
The present liquid developer~ are employed to develop electrostatic charge patterns carried by various types of elements. Such elements are either photoconductive themselves, i.e., image-forming sur-faces, or adapted to receive charge images, i.e., image-receiving surfaces, as disclosed in US Patent 3,519,819 issued July 7, 1970. For example, the developers may be used with photoconductive film ele-ments containing arylmethane photoconductor composi-,~
1JL7~886 tions such as those disclosed in US Patent 4,301,226issued November 17, 1981.
The following examples are included for a further understanding of the invention.
Examples:
Preparation of Liquid Developer The following illustrates the preparation of liquid developers in accordance with the present invention. Various concentrates, each containing separate developer components in Solvesso 100~
alkylated aromatic liquid, were prepared. Concen-trates containing dispersed (insoluble) components in the Solvesso 100~ were solvent ball-milled. The Solvesso 100~ concentrates included the following in approximately 10%-by-weight concentrations:
(A) colorantl and charge-control polymer, (B) polyester resin2, (C) auxiliary charge-control polymer, (D) wax3 and disper~ing agent~ and (E) polyester platicizer5.
Raven 1255~ carbon black available from Cit-ies Service Company
m e present lnventlon relates to ~elr_ fixing liguid electro~tatlc image de~eloper~ comprising as a dlspersed component, a compatlble blend o~ at least one polyester blnder and at lea~t one polye~ter plastlclzer, to image~ formed ~rom such developer~, and to methods of formlng images with such developers.
Electrographlc imaglng and development processes have been extenslvely described in both the patent and other llterature. Cenerally, these processes have in common the step~ of formlng an electrostatlc charge image, often called an electro-static latent image, on an lnsulatlng sur~ace, such as a photoconductive lnsulating layer coated on a conductive ~upport. m- electrostatic latent image i8 then rendered vl~lble by a development step ln which the charge image_bearing ~urface 18 brought into contact with a suitable electrostatlc image developer compositlon which deposits toner particle on either the charged or uncharged lmage areas. After development, the visible image i8 either heat_flxed dlrectly to the electrostatlc charge_bearing sur~ace or lt 18 transferred to another surface such as paper where lt 18 there heat-~ixed.
Llquid developer compositions of the type de~cribed ln U.8. Patent No. 4,202,785 are very useful for developlng latent electrostatlc images.
m ese developer~ comprl~e a stable dl perslon o~
dlsper~ed componQnts and dl~olved component~ in an electrically ~nsulating carrler ll~uld. The dlspersed component~ include charged p~rtlcle~, ~nown a~ toner partlcle~, comprl~lng ~ colorant or pigment, ~uch a~
carbon black, generally a~ociated wlth a thermo_ plastlc re~ln blnder. The dl~solved component~
_2-include optional organic liquids from previous steps ln the preparation of the liquid developer, as well as optional charge control agents.
Liquid developers containing polyester resin binders such as those disclosed in the afore-mentloned U.S. Patent No. 4,202,785 as well as developers containing other polyester resin binders are particularly useful. As noted in the said U.S. patent, however, the polyesters are fixed to receiving surfaces by the application of heat. Heat_fixable polyesters having very high glass transition temperatures (Tg), (i.e., above 150C) thus require higher fixing temperatures as well as careful selection of the receiving support to avoid support distortion or charring.
In the published patent literature, various llquid toner formulations having self-fixing qualities are reported. For example, U.S. Patent 3,954,640 reports the use of low Tg linear addition polymers to give liquid developers and lnks that become fixed to a substrate with little or no carrier evaporation in the a~sence of heat. It ls essential to this patent that the polymer Tg be no higher than 35C.
m e patent further discloses the use of monomeric plasticizers as optional components that are miscible in the carrier. ~ The purpose of the plasticizer is to ad~ust the ability of the carrier to disperse the polymer resin.
U.K. Patent 1,110,225 describes a liquid developer which is sald to be self_fixing upon removal of the carrier liquid ~ollowing deposition of the toner particles. To achieve such self_fixing, the patent discloses the use of liquid alkyd resins which, because of their unsaturated chemical bond linkages, cure in air upon removal of the carrier liquid. Toner particles containing oxidizing type unsaturated alkyd ~74~386 resins in combination with certain phenol modified pen-taerythritol ester resins are also noted in UK Patent 897,903.
Also from the patent literature, the use of certain plasticizers is reported in liquid toner formu-lations for purposes entirely unrelated to selffixing.
Thus, for example, it is reported that toner adhesion to a substrate can be achieved by tack modification;
that i6, through the addition of modifying agents, a resin binder can be rendered suitably tacky to adhere to a surface of choice. According to Smith et al US
Patent 3,939,085 issued February 17~ 1976, the addition of monomeric plasticizers to toner resins produces a toner composition which has low adhesion for an image-forming surface and high adhesion for a copy surface.The adhesion differential facilitates transfer of toner images from the imageforming surface to the copy where the tacky quality is lost by curing. From the teach-ings of this patent, therefore, it would appear that the use of plasticizers will not produce a toner which self-fixes to an image-forming surface.
US Patent ~,839,032 issued October 1, 1974, relates to the use of carrier-soluble monomeric and polymeric plasticizing agents for the toner binder resin. The use of carrier-soluble plasticizers, how-ever, is undesirable as they tend to le&ch out of the binder resin into the carrier, thus negating any poten-tial benefit from ther use. Furthermore, this document does not teach that its toners are self-fixing.
In &ccordance with the presnet invention, a self-fixing liquid electrographic developer is provided exhibitng, in its broadest aspects, several significant advantages. The developer is self-fixing without resort to tacky low-T binder polymers. The self-fixing property, moreover, is exhibited specifically on an electrostatic image-bearing surface without fear ~L~7~86 of unwanted transfer to other surfaces. Furthermore, the liquid developer exhibi~ its self-fixing property immediately upon extraction o~ the image-bearing surface or element from the liquid development region, in contrast to the prior art methods relying upon further chemical reaction of included curing agents having unsaturated chemical groups.
These and other advantages are achieved with a liquid electrographic developer composition which self-fixes to an electrostatic image-forming surface.
According to the present invention there is provided a liquid electrostatic image developer composition comprising an electrically insulating organic carrier liquid contain~ng, as a dispersed constituent, a plurality of toner particles comprising a compatible blend of at least one polyester resln and at least one polyester plasticizer, characterized in that the plasticizer is substantially free of curable groups and i~ substantially insoluble in the carrier liquid.
Self_fixing in the context of the present invention denotes the quality of forming a rub resistant image on an electrostatic image-bearing surface without resort to externally applied heat.
me self-fixing property, moreover, is substantially immediate, after the image_bearing surface is treated in and removed from the liquid developer, and any residual carrier evaporated to dryness. To determine whether a particular developer meets the sel~-~ixing criteria of the present invention one can employ a simple test to determine rub resistance. The rub test comprise~ the appllcatlon of a 700 gram wei pted olelc acid soaked patch approxlmately 5 mm in diameter to a toner_bearing image and oscillating a portion of the image back and forth underneath the absorbent ~7~386 patch. Oleic acid is chosen to simulate natural finger oil. Rub resistance is determined as a range A to B, wherein A is the number of oscillatory cycles (a cycle being one movement of the patch back and forth) lt takes to first interrupt the toner image integrity while B
represents the number of cycles necessary to completely remove the sub~ected portion of the image by such rubbing. Specific toner images prepared in accordance with the present invention, exhibit an A value of from 1 to 9 cycles and a ~ value of from 2 to 12 cycles whereas control images having no polyester plasticizer are completely removed (B) in one cycle. In the practice of this inventlon, higher A_B values are, of course, likely to be obtained depending on such factors as the materials used in the compatible blend of resin and plasticizer, as well as the nature of the surface to which the blend is self_fixed.
In the practice of the present invention, a compatible blend Or at least one polyester resin and at least one polyester plasticizer is used. The plasticizer i8 specifically free of curable groups, in contrast to prlor art materials such as alkyd resins that rely on further chemlcal reaction of curable groups to fix. The plasticizer, moreover, is substantially insoluble in the carrier liquid 80 as to prevent leaching Or the plasticizer into the carrier~ A
compatible blend in this regard, refers to the ability of the re~in and plasticizer to form a non_hazy solid solution of one in the other.
The ratio of components in the compatible blend varies widely in accordance with the user need~. A useful wei p t ratio of plasticizer to resin is in the range from 0.2 to 1Ø A preferred ratio is in the range from 0.25 to 0.5.
1~74~3~i Many polyester reslns are useful ~n the practice of the present invention. Typical polyesters include repeating diol units and diacid recurring units well known to those skilled in the art.
Representative polyesters are disclosed, for example in U.K. Patent 1,528,950. m is patent discloses a redi~persible liquid developer in which the polyester binder comprises disulphonamido groups.
Preferred polyester resins of the invention include ionic poiyesters comprlsing recurring diol units and recurring ionic diacid units. Representative preferred polyester binders have recurring diol units of the formula:
_ 0 G - 0- _ wherein:
Gl represents straight or branched chain alkylene ha~ing Z to 12 carbon atoms or, ~ubstituted or unsubstituted, cycloalkylene cycloalkylenebis(oxyalkylene) or cycloalkylene-dialkylene; d have up to 35 mole percent (based on the total moles of diacid units) of ionic diacid units of the formula:
t C A C t wherein:
A represents sulphoarylene, sulphoaryloxy-arylene, sulphocyclohexylene, arylsulphonyl_ imino, sulphonylarylene, iminobis(sulphonyl-arylene), sulphoaryloxysulphonylarylene and sulphoaralkylarylene or the alkali metal or ammonlum salts thereof.
~i7~886 5uch preferred polyester resin~ include, for example, the polyester ionomer resins disclosea in U.S. Patent 4,202,785.
In general, useful polyester resin-~ of the present invention have a glass transition temperature ~Tg) of from 40C to 100C. Polyester resins having a Tg in the aforementioned preferred range can be self-fixed to smooth_surfaced dielectric coated receiving elements, as well as ordinary support surfaces, such as photoconductive co~ted paper or film elements, without dif~iculty.
Materials having a Tg above 150C can also be used.
The glass transition temperatures can be determined by conventional methods, such as differential scanning calorimetry (DSC).
Useful polyester re~ins have an inherent viscosity of 0.01 to 0.65, preferably 0.16 to 0.~1.
Polyester resins havlng inherent viscosities in the preferred range are compatible with the preferred charge control agent~, optionally used in the liquid electrographic developers of the present lnvention.
Inherent viscositie~ of the polyesters are measured in a 1:1 by weight solution of phenol:chlorobenzene at 25C at a concentration of 0.25 gram per 100 ml of solution.
The p1asticizers employed in the compatible blend of resin snd plasticizer are chosen from among a variety of commercially availsble polyester pla8ticizerg hsving ~ Tg below -40C, preferably within the range from about -45C to about -70C. In selecting suitable msterial, the criteria of compatibility with the polyester binder is usually first employed to screen potentislly ~i7~386 .
useful materials. From smong these materials that satisfy the compatibility criteria, one then excludes plasticizers having curable chemic~l groups such as oil-modified polyester plasticizers or epoxidized 5 oils. Of the eligible plasticizers, ones are chosen that are insoluble in the electrically insulating carrier liquid as defined below.
~ 1~74~386 _9_ plasticizers, ones are chosen that are insoluble in the electrically insulating carrier liquid as defined below.
Representative useful polyester plasticizers that are insoluble in commonly employed isoparaffinic hydrocarbon carrier liquids such as that sold under the trade mark 'Isopar' G are listed in the following table by Trade Mar~ and commercial source.
TABLE I
Plasticizer Commercial Source 10 'San~icizer' 429 Monsanto Chemical Co.
'Santicizer' 409 Monsanto Chemical Co.
'Paraplex' C_25 Rohm and Haas Co.
'Paraplex' G_41 Rohm and Haas Co.
'Paraplex' G_57 Rohm and Haas Co.
15 'Paraplex' G_31 Rohm and Haas Co.
'Paraplex' G-40 Rohm and Haas Co.
'Eastman' NP_10 Eastman Koda~ Co.
Preferred polyester plasticizers include those sold under the Trade Marks 'Santicizer' 429, 'Paraplex' G_25, 'Paraplex' G_41 and 'Paraplex' G-57.
'Santicizer' 429, typifying the preferred materials, has the following physical properties:
Acidity 4.0 meq/100 gm max Refractive Index at 25C 1.460 to 1.470 Speclflc Gravity 25/25C . 1.080 to 1.110 Density (25C) ca. lbs./gal. 9.1 . Flash point 288C
Fire point 310C
Insoluble ln water at 25C
Tg -56C
1~74~3~6 Preferred polyester plasticizers comprlse repeating alkylene diol units having 2 to 6 carbon ~toms such as diol units derived from ethylene glycol or butylene diol, and repeating aliphatic diacid units having 3 to 10 carbon atoms such ag diacid units derived 11'74886 from malonic acid, succinic acid or adipic acid. A
particularly preferred polyester plasticizer comprises an acetate terminated adipic acid-butylene glycol polyester.
m e polystyrene equivalent molecular weight of the preferred polyester plasticizers rangeæ from 7000 to 9000 as determined by gel permeation chromatography.
The compatible blend of resin and plasticizer defined above is formed in a variety of ways that facilitate the formation of small particles, preferably of submicron size (l.e., 0.01 to 1.0 micron average particle size). A preferred method of forming the blend comprises preparing a concentrated solution of the plasticizer and resin in a common solvent such as 'Solvesso' 100 (the trade mark for an alkylated aromatic having a ma~or aromatic component and a boiling range of from 150_185C sold by Humble Oil & Refining Co., U.S.A.). me concentrated solution ls thereafter mixed with a large excess Or the liquid carrier to precipitate particles of the plasticizer_resin blend in working developer concentration strength~.
The carrier liquid employed according to the present invention is selected from a varlety of materials that satiæfy the plasticizer insolubility criteria. These materlals should be electrically insulating and have a fairly low dielectric constant.
Useful carrier liquids have a dielectric constant of less than 3, and a volume resistivity greater than 101 ohmlcm. Suitable carrier liqulds include halogenated hydrocarbon solvents, for example, fluorinated lower alkanes, such as trichloromono_ fluoromethane and trlchlorotrifluoroethane, having a boiling range typically from 2C to 55C. Other ~ 4 hydrocarbon solvents which are useful include iso-paraffinic hydrocarbons having a boiling range of from 145 to 185 C, such as Isopar G~, or cyclohydrocarbons, such as cyclohexane. Additional S carrier liquids which are useful include polysilox-anes, odorlesæ mineral spirits and octane.
In general, useful working-strength devel-opers of the present invention contain from 0.005 to 5 percent by weight of the plasticizer-resin blend. These developers contain from 99.999 to 90 percent by weight of the liquid carrier vehicle.
Although it is possible to use the liquid developers of the present invention without further addenda, it is often desirable to incorporate such addenda as charge-control agents, waxes and dis-persing agents for the wax or colorants in the developer.
If a colorless image is desired, it i8 unnecessary to add any colorant. For example, the developer may be used to form a colorless hydropho-bic image in a lithographic printing process. In such case, the resultant developer composition con-sists essentially of the liquid carrier behicle and the plasticizer-resin blend particles of the pres-ent invention.
In accordance with a preferred embodimentof the present invention, however, colorants such as carbon black pigments are also included in the liquid developer defined. In this regard, it has been determined that images formed from toners com-prising polyester resin binder and colorants exhibit a tendency to crack in a pattern resembling that of the bed of a dried lake, the so-called adobe pattern. This tendency is significantly reduced and often eliminated with the presently defined blend of resin-plasticizer. Accordingly, the present invention contemplates the use of ~' ~'74~3a6 colorant-containing developers to produce self-fixing and crack-resistant visible images. Useful results are obtained from virtually any of a wide variety of known dyes or pigment materials. Par-ticularly good results are obtained by using vari-ous kinds of carbon black pigments.
A representative list of colorants are found, for example, in Researc _ sclosure, Vol.
109, May, 1973, in an article entitled "Electropho~
tographic Elements, Materials and Processes".
The colorant concentration, when colorant is present, varies widely with a useful concentra-tion range, by weight of the total dispersed con-stituents, being 10 to 90 percent. A preferred concentration range is from 35 to 45 percent.
Waxes and dispersing agents for the wax are also included as optional dispersed components in the present developers. Suitable waxes and dispers-lng agents include those described in Canadian Serial No. 397,476 by Alexandrovich and Upson filed March 3, 1982, which describes liquid electrographic developers comprising an electrically insulating organic carrier liquid containing dispersed con-stituents and dissolved constituents, said dissolved constituents comprising an electrically insulating organic dispersing liquid which forms a solution with said carrier liquid, said dispersed constitu-ents comprising at least one thermoplaætic resin and wax particles, and characterized in that said devel-oper also contains a dispersing agent for said waxparticles which is insoluble in said solution of carrier liquid and dispersing liquid, but soluble in said dispersing liquid alone. Preferably, the wax particles are a polyolefin wax, carnauba wax, an ester wax or an amide wax. The dispersing liquid used with these waxes is preferably an alkylated ~.~7~386 aromatic liquid when the carrier liquid is an iso-paraffinic hydrocarbon.
Optionally, the developers of the present invention include various charge control agent~ to enhance uniform charge polarity on the developer toner particles.
Various charge control agents have been described heretofore in the liquid developer art.
Examples of such charge control agents may be found in U.S. Patent No. 3,788,995 which describes various polymeric charge control agents. Other useful charge control agents include phosphonate materials described in U.S. Patent No. 4,170,56~ and quaternary ammonium polymers descrlbed in U.S. Patent No. 4,229,513.
Various optional non_polymeric charge control agents are also employed such as the metal salts described in U.S. Patent No. 3,417,019. Other charge control agents known in the liquid developer art may also be employed.
A partial listing of preferred representative polymeric charge control agents for use in the present invention includes poly(styrene-co-lauryl methacrylate_ co_sulphoethyl methacrylate), poly(vinyltoluene_co_ lauryl methacrylate-co-lithium methacrylate_co_meth_ acrylic acid), poly(styrene_co_lauryl methacrylate_co_ lithium sulphoethyl methacrylate), poly(~inyltoluene_co_ lauryl methacrylate-co_lithium methacrylate), poly-(styrene-co-lauryl methacrylate_co_lithium methacrylate), poly(t_butylstyrene_co_lauryl methacrylate_co-lithium methacrylate, poly(t_butylstyrene_co_lithium meth_ acrylate), or poly~vinyl toluene_co_lauryl methacrylate-co_methacryloyloxyethyl trimethylammonium p_toluene ~ulphonate).
1~174~386 The amount of charge-control agent used will vary depending upon the particular charge-control agent and its compatibility with the other component6 of the developer. It is uæually desirable to employ an amount of charge-control agent within the range of from 0.01 to 10.0 weight percent based on the total weight of a working-strength liquid developer compo-sition. The charge-control agent may be added in the liquid developer simply by dissolving or dispersing the charge-control agent in the liquid carrier vehicle at the time concentrates of the components are combined with the liquid carrier vehicle to form a working-strength developer.
Various techniques are employed to prepare a working-strength developer comprising the aforemen-tioned plasticizér-binder blend. For example, as disclosed in US Patent 4,202,785 by Hartman issued May 13, 1980, one or more developer concentrates are prepared for each of the developer components (a con-centrate ls a concentrated solution or dispersion ofone or more developer components in a suitable elec-trically insulating liquid vehicle not necessarily the developer carrier liquid). The concentrates are then admixed in a preselected sequence, the admixture slurried with the carrier liquid to dilute the compo-nents, and the slurry homogenized to form the working-strength developer.
The present liquid developer~ are employed to develop electrostatic charge patterns carried by various types of elements. Such elements are either photoconductive themselves, i.e., image-forming sur-faces, or adapted to receive charge images, i.e., image-receiving surfaces, as disclosed in US Patent 3,519,819 issued July 7, 1970. For example, the developers may be used with photoconductive film ele-ments containing arylmethane photoconductor composi-,~
1JL7~886 tions such as those disclosed in US Patent 4,301,226issued November 17, 1981.
The following examples are included for a further understanding of the invention.
Examples:
Preparation of Liquid Developer The following illustrates the preparation of liquid developers in accordance with the present invention. Various concentrates, each containing separate developer components in Solvesso 100~
alkylated aromatic liquid, were prepared. Concen-trates containing dispersed (insoluble) components in the Solvesso 100~ were solvent ball-milled. The Solvesso 100~ concentrates included the following in approximately 10%-by-weight concentrations:
(A) colorantl and charge-control polymer, (B) polyester resin2, (C) auxiliary charge-control polymer, (D) wax3 and disper~ing agent~ and (E) polyester platicizer5.
Raven 1255~ carbon black available from Cit-ies Service Company
2 polytneopentyl-4-methylcyclohexene-1,2-dica -boxylate-co-terephthalate-co-5-(N-potassio-~-toluene sulphonamidosulphonyl)isophthalate]
3 Shamrock Chemicals Corporation S-394~ poly-ethylene wax Elvax 210~, an ethylene/vinylacetate copoly-mer available from duPont 5 Santicizer 429~ polyester plasticizer available from Monsanto Chemical Co.
Preselected portions of each concentrate were admixed with sufficient Isopar G~ isopar~ffinic hydrocarbon carrier liquid and the resulting diluted mixture homogenized to form 1 liter of a working-strength de~eloper containing 1 part (0.7 gram) colorant per liter. The concentrations of the other ~74~386 components, by parts, were as follows:
Colorant 1 part Charge control polymer 1.2 parts Polyester resin 1.2 parts Auxiliary charge control polymer 0.175 part Wax 0.25 part Dispersing agent 0.125 part Plasticizer X
where X represented varied concentrations of plasticizer in five different developers as shown in Examples 1 to 5.
ExamPles 1 to 5 The developers prepared as above for plasticizer concentrations X=0, 0.25, 0.375, 0.50 and 1.0 were employed to form toned images on a photo_ conductive recording film element without application of heat to fix the images. The film element comprises a film support, an electrically conducting layer overlying the suppsrt and a photoconductive layer overlying the conductlve layer.
m e resulting images were observed on a microfiche viewer screen at 24X magnification and the presence or non_presence of image cracking noted.
Images of varied density for each developer were also sub~ected to the olelc acid rub test described above to assess their self-fixlng qualities. Results are shown in Table II.
.. .
` 117~86 TABLE II
X Imaze Ima~e Oleic Acid ExamPle (parts) DensitY Crackin~ Rub (A_B) CYcles l(control) 0 1.1 Yes l*
5- 0 0.7 Yes l*
2 0.25 1.2 No 3-5 0.25 0.8 No 1_2 3 0.375 1.2 No 5_11 0.375 0.8 No 3_6 10 4 0.5 1.3 No 4_8 0.5 0.8 No 2_4 1.0 1.4 No 1_2 1.0 0.9 No 1-2 *represented complete removal after one rub.
15 Exam~les 6 and 7 Two developers were prepared as above having the followlng concentration of components Colorant 1 part Charge control polymer 1.2 parts Polyester resin 1.2 parts Auxiliary charge control polymer 0.1 part Plasticizer X
The developers were employed to form images as in Examples 1 to 5 and the images assessed for olelc acid rub resistance. m e results are shown in Table III.
TABLE III
X Image Oleic Acid Exa le t arts)DensitY R~b (A_B) 6 control 0 1.8 1.0 7 0.5 2.2 9-25 1.2 4_8 i 1174~86 -19_ Exam~les 8 to 10 Three developers were prepared and employed to form images as above. In each developer, carbon black was replaced with the colorant shown below:
5 Example 8 Cyan Blue GTNF
(American Cyanamid) 1 part Charge control polymer 0.9 part Polyester resin 1 part Auxiliary charge control polymer 0.1 part Plasticizer 0.5 part Example 9 'Sunfast' Quinacridone (Sun Chemicals Co.) 1 part Charge control polymer 0.8 part Polyester resin 1 part Auxillary charge control polymer 0.1 part Plast~clzer 0.5 part Example 10 Lemon Metallic Yellow (Sun Chemical Co.) 1 part Charge control polymer 1 part Polyester resin 1 part Auxlliary charge control polymer 0.2 part Plasticizer 0.5 part Each of the developers was noted to exhibit ~elf_fixing.
Exam~les ll to 15 The followlng developer~ were prepared and employed to form images a~ ln above Examples 1_5:
Colorant 1 part Charge control polymer 1.4 parts Polye-qter re~ln 1.2 parts Auxlllary charge control polymer 0.2 part Plasticlzer X
~ li74~386 Five developers were prepared with values of X equal to 0, 0.125, 0.25, 0.50 and 1.0, m e cracking Or the images, if any, was noted as in Examples 1_5 and reported below in Table IV by severity.
TABLE rv X
ExamPle (Parts) Toner Crackin~
11 control 0 Very heavy 12 0.125 Moderate to heavy 13 0.25 Slight, pinhole type 14 0.50 None 1.0 None
Preselected portions of each concentrate were admixed with sufficient Isopar G~ isopar~ffinic hydrocarbon carrier liquid and the resulting diluted mixture homogenized to form 1 liter of a working-strength de~eloper containing 1 part (0.7 gram) colorant per liter. The concentrations of the other ~74~386 components, by parts, were as follows:
Colorant 1 part Charge control polymer 1.2 parts Polyester resin 1.2 parts Auxiliary charge control polymer 0.175 part Wax 0.25 part Dispersing agent 0.125 part Plasticizer X
where X represented varied concentrations of plasticizer in five different developers as shown in Examples 1 to 5.
ExamPles 1 to 5 The developers prepared as above for plasticizer concentrations X=0, 0.25, 0.375, 0.50 and 1.0 were employed to form toned images on a photo_ conductive recording film element without application of heat to fix the images. The film element comprises a film support, an electrically conducting layer overlying the suppsrt and a photoconductive layer overlying the conductlve layer.
m e resulting images were observed on a microfiche viewer screen at 24X magnification and the presence or non_presence of image cracking noted.
Images of varied density for each developer were also sub~ected to the olelc acid rub test described above to assess their self-fixlng qualities. Results are shown in Table II.
.. .
` 117~86 TABLE II
X Imaze Ima~e Oleic Acid ExamPle (parts) DensitY Crackin~ Rub (A_B) CYcles l(control) 0 1.1 Yes l*
5- 0 0.7 Yes l*
2 0.25 1.2 No 3-5 0.25 0.8 No 1_2 3 0.375 1.2 No 5_11 0.375 0.8 No 3_6 10 4 0.5 1.3 No 4_8 0.5 0.8 No 2_4 1.0 1.4 No 1_2 1.0 0.9 No 1-2 *represented complete removal after one rub.
15 Exam~les 6 and 7 Two developers were prepared as above having the followlng concentration of components Colorant 1 part Charge control polymer 1.2 parts Polyester resin 1.2 parts Auxiliary charge control polymer 0.1 part Plasticizer X
The developers were employed to form images as in Examples 1 to 5 and the images assessed for olelc acid rub resistance. m e results are shown in Table III.
TABLE III
X Image Oleic Acid Exa le t arts)DensitY R~b (A_B) 6 control 0 1.8 1.0 7 0.5 2.2 9-25 1.2 4_8 i 1174~86 -19_ Exam~les 8 to 10 Three developers were prepared and employed to form images as above. In each developer, carbon black was replaced with the colorant shown below:
5 Example 8 Cyan Blue GTNF
(American Cyanamid) 1 part Charge control polymer 0.9 part Polyester resin 1 part Auxiliary charge control polymer 0.1 part Plasticizer 0.5 part Example 9 'Sunfast' Quinacridone (Sun Chemicals Co.) 1 part Charge control polymer 0.8 part Polyester resin 1 part Auxillary charge control polymer 0.1 part Plast~clzer 0.5 part Example 10 Lemon Metallic Yellow (Sun Chemical Co.) 1 part Charge control polymer 1 part Polyester resin 1 part Auxlliary charge control polymer 0.2 part Plasticizer 0.5 part Each of the developers was noted to exhibit ~elf_fixing.
Exam~les ll to 15 The followlng developer~ were prepared and employed to form images a~ ln above Examples 1_5:
Colorant 1 part Charge control polymer 1.4 parts Polye-qter re~ln 1.2 parts Auxlllary charge control polymer 0.2 part Plasticlzer X
~ li74~386 Five developers were prepared with values of X equal to 0, 0.125, 0.25, 0.50 and 1.0, m e cracking Or the images, if any, was noted as in Examples 1_5 and reported below in Table IV by severity.
TABLE rv X
ExamPle (Parts) Toner Crackin~
11 control 0 Very heavy 12 0.125 Moderate to heavy 13 0.25 Slight, pinhole type 14 0.50 None 1.0 None
Claims (15)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A liquid electrostatic image developer composition comprising an electrically insulating organic carrier liquid containing, as a dispersed constituent, a plurality of toner particles comprising a compatible blend of at least one poly-ester resin and at least one polyester plasticizer, characterized in that the plasticizer has a glass transition temperature below -40° C and is substantially free from curable groups and is substantially insoluble in the carrier liquid.
2. A developer according to Claim 1 characterized in that the polyester resin is a polyester ionomer having ionic diacid recurring units.
3. A developer according to Claim 2 characterized in that the polyester has a glass transition temperature of at least 40°C.
4. A developer according to Claim 3 characterized in that the polyester plasticizer comprises diol recurring units derived from alkylene diols having 3 to 10 carbon atoms and diacid recurring units derived from aliphatic diacids having 2 to 6 carbon atoms.
5. A developer according to Claim 4 characterized in that the polyester plasticizer comprises butylene diol units and adipic acid units.
6. A developer according to Claim 5 characterized in that the weight ratio of polyester plasticizer to polyester resin is from 0.2 to 1.
7. A developer according to Claim 6 characterized in that the weight ratio of polyester plasticizer to polyester resin is from 0.25 to 0.5.
8. A developer according to Claim 7 characterized in that the toner particles contain a colorant.
9. A developer according to Claim 8 characterized in that the colorant is carbon black.
10. A developer according to Claim 7 charac-terized in that it contains a charge-control agent
11. A developer according to Claim 10 charac-terized in that the charge-control agent is a poly-(styrene-co-lauryl methacrylate-co-sulphoethyl meth-acrylate), poly(vinyl-toluene-co-lauryl methacrylate-co-lithium methacrylate-co-methacrylic acid), poly-(styrene-co-lauryl methacrylate-co-lithium sulpho-methacrylate), poly(vinyltoluene-co-lauryl methacry-late-co-lithium methacrylate), poly(t-butylstyrene-co-lauryl methacrylate-co-lithium methacrylate), poly(t-butylstyrene-co-lithium methacrylate) or poly-(vinyl toluene-co-lauryl methacrylate-co-methacryl-oyloxyethyl trimethylammonium p-toluene sulphonate).
12. A developer according to Claim 11 charac-terized in that the charge-control agent is present in a range from 0.01 to 10 percent by weight based on the weight of developer.
13. A developer according to Claim 7 charac-terized in that the carrier liquid is an isoparaf-finic hydrocarbon.
14. The method of forming a toner imasge comprising treating a surface bearing an electro-static charge image with a liquid electrostatic image developer characterized in that the electrostatic image developer is as claimed in Claim 13.
15. A toner image-bearing surface whenever made by the method of Claim 14.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US25271581A | 1981-04-10 | 1981-04-10 | |
| US252,715 | 1981-04-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1174886A true CA1174886A (en) | 1984-09-25 |
Family
ID=22957214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400733A Expired CA1174886A (en) | 1981-04-10 | 1982-04-08 | Self-fixing electrographic developer including toner particles comprising a polyester resin and a polyester plasticizer |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0076316B1 (en) |
| JP (1) | JPS58500541A (en) |
| CA (1) | CA1174886A (en) |
| DE (1) | DE3274907D1 (en) |
| WO (1) | WO1982003700A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4659640A (en) * | 1982-06-21 | 1987-04-21 | Eastman Kodak Company | Self-fixing liquid electrographic developers containing polyester toners and dispersed wax and processes for using the same |
| US4480022A (en) * | 1982-09-27 | 1984-10-30 | Eastman Kodak Company | Method for forming a self-fixed image on a nonporous surface at ambient temperature |
| US5308729A (en) * | 1992-04-30 | 1994-05-03 | Lexmark International, Inc. | Electrophotographic liquid developer with charge director |
| JP5544958B2 (en) * | 2010-03-18 | 2014-07-09 | 富士ゼロックス株式会社 | Liquid developer, process cartridge, and image forming apparatus |
| JP5578037B2 (en) * | 2010-11-08 | 2014-08-27 | 富士ゼロックス株式会社 | Method for producing liquid developer |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3939085A (en) * | 1971-06-21 | 1976-02-17 | Savin Business Machines Corporation | Process for forming a liquid developer organisol |
| US3888678A (en) * | 1971-07-16 | 1975-06-10 | Eastman Kodak Co | Method for adjusting triboelectric charging characteristics of materials |
| US4024292A (en) * | 1973-06-27 | 1977-05-17 | Xerox Corporation | Process for developing latent electrostatic images with ink |
| US3954640A (en) * | 1973-06-27 | 1976-05-04 | Xerox Corporation | Electrostatic printing inks |
| CA1062069A (en) * | 1974-12-23 | 1979-09-11 | Eastman Kodak Company | Liquid electrographic developer composition and process |
| US4052325A (en) * | 1974-12-23 | 1977-10-04 | Eastman Kodak Company | Liquid electrographic developer composition containing redispersible polyester toner and process |
| AU3909078A (en) * | 1977-08-24 | 1980-02-28 | Commw Scient Ind Res Org | Electrostatic liquid developer |
| US4202785A (en) * | 1978-05-15 | 1980-05-13 | Eastman Kodak Company | Polyesterionomers having utility in liquid electrographic developer compositions |
-
1982
- 1982-04-08 CA CA000400733A patent/CA1174886A/en not_active Expired
- 1982-04-08 JP JP50149982A patent/JPS58500541A/en active Pending
- 1982-04-08 DE DE8282901480T patent/DE3274907D1/en not_active Expired
- 1982-04-08 WO PCT/US1982/000435 patent/WO1982003700A1/en active IP Right Grant
- 1982-04-08 EP EP19820901480 patent/EP0076316B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0076316B1 (en) | 1986-12-30 |
| DE3274907D1 (en) | 1987-02-05 |
| JPS58500541A (en) | 1983-04-07 |
| WO1982003700A1 (en) | 1982-10-28 |
| EP0076316A4 (en) | 1983-09-26 |
| EP0076316A1 (en) | 1983-04-13 |
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