BR102014025050A2 - hybrid emulsion aggregate toner - Google Patents

Abstract

hybrid emulsion aggregate toner. Toners and processes useful for providing toners suitable for electrophotographic apparatus, including apparatus such as digital, image-in-image and similar apparatus. in particular, emulsion aggregate toner compositions using two different emulsion aggregation (ea) technologies and comprising a base resin composed of styrene acrylate and polyester resins. These toner compositions additionally include polyaluminium chloride (pac) instead of the most commonly used aluminum sulfate as the flocculating agent or aggregator.

Description

HYBRID EMULSION AGGREGATE TONER

The present disclosure relates to toners and methods useful for providing toners suitable for electrophotographic apparatus, including apparatus such as digital, image-in-image and similar apparatus. In particular, the disclosure relates to emulsion aggregate toner compositions using two different emulsion aggregation (EA) technologies. That is, the present embodiments provide an emulsion aggregation toner comprising a base resin composed of both styrene acrylate and polyester resins. These embodiments comprise polyaluminium chloride (PAC) instead of the most commonly used aluminum sulfate as the flocculating agent or aggregator. Toners made in this manner have improved surface morphology and achieved improved toner blocking and percentage heat cohesion, particularly for black toner. In addition, such hybrid emulsion aggregation toner compositions are lower in cost but still retain desirable developer properties such as low minimum melt temperature (MFT) and low dielectric loss.

Emulsion aggregation toners may comprise various resins for use in latex formation. One type of emulsion aggregate toner provides high gloss and uses styrene acrylate, a lower cost resin. Another type of emulsion aggregation toner provides better melting performance (for example, lowest minimum setting temperature (MFT) of about 20 ° C) and uses polyesters as the base resin. However, the polyester resins used are costly. Thus, the present embodiments seek to form a hybrid emulsion aggregation toner that combines the advantages of both types of toners. However, it has been found that styrene-acrylate latex toners do not melt at the same temperature during the toner process as polyester toners, thus leading to variation in surface morphology in a hybrid of both toner types (a higher amount of polystyrene / acrylate remains on the surface). The present embodiments replace somewhat of the polyester resin used in the lower melt toner core with some of the high gloss toner styrene acrylate and include PAC as the aggregating agent. Such a hybrid composition provides a lower cost toner that maintains good fusing performance and low dielectric loss. In addition, PAC interestingly improves surface morphology by reducing the amount of styrene acrylate on the surface.

The present embodiments provide a toner composition a toner composition comprising: toner particles having a core, wherein the core comprises a resin, a dye, a wax and polyaluminium chloride, wherein the resin comprises a styrene resin -acrylate, a crystalline polyester resin and an amorphous polyester resin; and a cover arranged over the core.

[0004] Figure 1A provides scanning electron microscope (SEM) images of comparative polyester-based toner particles;

Figure 1B provides SEM images of a hybrid toner made in accordance with the present embodiments;

Figure 1C provides SEM images of other hybrid toner made in accordance with the present embodiments; and [0007] Figure 2 is a graph illustrating the improved heat cohesion% of toner made according to the present embodiments compared to control toners.

In embodiments, styrene acrylate resin is present in the toner particle core in an amount of from about 5% to about 35%, or from about 10% to about 35%, or about 20%. about 35% by weight of the total core weight. In embodiments, the particle size of the styrene acrylate emulsion is from about 100 nm to about 160 nm, or from about 100 nm to about 140 nm.

The use of styrene acrylate resin in this range along with PAC has been found to provide excellent results on EA toner with good performance and properties and improved surface morphology.

In embodiments, the resins may be a polyester resin, such as an amorphous resin, a crystalline resin, and / or a combination thereof, including the resins described in US Patent Nos. 6,593,049 and 6,756,176. , the disclosure of each of which is hereby incorporated by reference in its entirety. Suitable resins may also include a mixture of an amorphous polyester resin and a crystalline polyester resin as described in U.S. Patent No. 6,830,860, the disclosure of which is hereby incorporated by reference in its entirety.

In embodiments, crystalline polyester resins are present in the toner particle core in an amount of from about 1% to about 20%, or from about 1% to about 15%, or from about 3% to about 10%. about 10% by weight of the total core weight. In embodiments, the crystalline polyester resin used in the core is selected from the group consisting of poly (ethylene adipate), poly (propylene adipate), poly (butylene adipate), poly (pentylene adipate), poly ( hexylene adipate), poly (octylene adipate), poly (ethylene succinate), poly (propylene succinate), poly (butylene succinate), poly (pentylene succinate), poly (hexylene succinate), poly (octylene) succinate), poly (ethylene sebacate), poly (propylene sebacate), poly (butylene sebacate), poly (pentylene sebacate), poly (hexylene sebacate), poly (octylene sebacate), poly (decylene sebacate) sebacate), poly (decylene decanoate), poly (ethylene decanoate), poly (ethylene dodecanoate), poly (nonylene sebacate), poly (nonylene decanoate), copoli (ethylene fumarate), copoli (ethylene sebacate) ), copoli (ethylene fumarate), copoli (ethylene decanoate), copoli (ethylene fumarate), copoli (ethylene dodecanoate), copoli (ethylene fumarate) -copoli (ethylene dodecanoate) to further reduce the cost . Preferred low cost crystalline polyesters are poly (1,9-nonylene-1,12-dodecanoate), poly (1,6-hexylene-1,12-dodecanoate) and poly (1,6-hexylene-1,10-decanoate) ).

In embodiments, crystalline polyester resins are present in the toner particle core in an amount of from about 20% to about 80%, or from about 20% to about 70%, or from about 30% to about 50%. about 65% by weight of the total core weight. These amorphous polyester resins are selected from the group consisting of poly (alkoxylated bisphenol-A co-fumarate - coterephthalate-cododecenyl succinate) and mixtures thereof. In embodiments, as noted above, an amorphous unsaturated polyester resin may be used as a latex resin. In one embodiment, the amorphous polyester resin may be obtained from Kao Corporation as FXC42 and FXC56. Examples of such resins include those disclosed in U.S. Patent No. 6,063,827, No. 8,466,254, the disclosure of which is incorporated herein by reference in its entirety. Unsaturated amorphous polyester resins include, but are not limited to, poly (propoxylated bisphenol co-fumarate), poly (ethoxylated bisphenol co-fumarate), poly (butyloxylated bisphenol co-fumarate), poly (bisphenol co-fumarate) co-ethoxylated and co-propoxylated bisphenol), poly (1,2-propylene fumarate), poly (propoxylated bisphenol co-maleate), poly (ethoxylated bisphenol co-maleate), poly (butyloxylated bisphenol co-maleate) , poly (co-ethoxylated bisphenol co-maleate and co-propoxylated bisphenol), poly (1,2-propylene maleate), poly (propoxylated bisphenol co-itaconate), poly (ethoxylated bisphenol co-itaconate), poly (butyloxylated bisphenol co-itaconate), co-ethoxylated bisphenol co-itaconate and co-propoxylated bisphenol), 1,2-propylene poly (itaconate) poly (bisphenol co-propoxylated bisphenol co-etixolated bisphenol co- fumarate coterephthalate co-dodecenisucinate) and combinations thereof.

The emulsion aggregation toner of the present embodiments has a minimum fusing temperature (MFT) of from about 90 to about 150, or from about 100 to about 130 or about 100 to about 125. That is. from about 15 to about 20 less than other non-polyester emulsion aggregation toners in the core or cap. The present embodiments also have acceptable dielectric loss of about 10 to about 40, or about 20 to about 40, or about 20 to about 35. From previous studies, the present inventors have found that dielectric loss of toners can be improved by increased layer thickness and decreased coalescing temperature. As such, the present toner composition has a preferable cover percentage of about 28% to about 40%, or about 30% to about 38%, or about 30% to about 36% of the toner particles. Toner For making such toner compositions, the coalescing temperature used is preferably from about 70 ° C to about 90 ° C or from about 70 ° C to about 80 ° C or from about 70 ° C to about 77 ° C. In particular embodiments, the latex particle size used to make such toner compositions is about 100 nm to 159 nm. The present inventors have also found that lowering the coalescing temperature and using smaller latex particle sizes helps to prevent any phase separation of styrene acrylate resin from polyester resins and keep styrene acrylate in the core rather than migrating to the core. surface. In this way good electrical and melting properties are maintained.

In embodiments, a developer is disclosed including a resin coated carrier and a toner, wherein the toner may be an emulsion aggregation toner, containing, but not limited to, a latex resin, a wax and a cover. of polymer.

Generally the latex resin may be composed of a first and a second monomer composition. Any suitable monomer or monomer mixture is selectable to prepare the first monomer composition and the second monomer composition. The selection of monomer or monomer mixture for the first monomer composition is independent of that for the second monomer composition and vice versa. In case a mixture of monomers is used, the latex polymer will normally be a copolymer. As discussed above, the latex resin is composed of at least styrene acrylate, a polyester resin and a crystalline resin.

Exemplary monomers for the first or second monomer compositions include, but are not limited to, polyesters, styrene, alkyl acrylate such as methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, dodecyl. acrylate, n-octyl acrylate, 2-chloroethyl acrylate; carboxy-β ethyl acrylate (β-CEA), phenyl acrylate, methyl alpha-chloroacrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate; butadiene; isoprene; methacrylonitrile; acrylonitrile; vinyl ethers, such as vinyl methyl ether, isobutyl vinyl ether, ethyl vinyl ether and the like; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate; vinyl ketones such as vinyl methyl ketone, hexyl vinyl ketone and isopropenyl methyl ketone; vinylidene halides, such as vinylidene chloride and vinylidene chlorofluoride; N-vinyl indole; N-vinyl pyrrolidone; methacrylate; acrylic acid; methacrylic acid; acrylamide; methacrylamide; vinylpyridine; vinylpyrrolidone; N-vinyl methylpyridinium chloride; vinyl naphthalene; p-chlorostyrene; vinyl chloride; vinyl bromide; vinyl fluoride; ethylene; propylene; butylenes; isobutylene; and their mixtures.

In some embodiments, the first monomer composition and the second monomer composition may independently comprise two or three or more different monomers.

The crystalline resin may have various melting points, for example from about 30 ° C to about 120 ° C, in embodiments of about 50 ° C to about 90 ° C. The crystalline resin may have a number average molecular weight (Mn) as measured by gel permeation chromatography (GPC) of, for example, from about 1,000 to about 50,000, in embodiments of from about 2,000 to about 25,000. and a weight average molecular weight (Mw) of, for example, from about 2,000 to about 100,000, in the modalities of about 3,000 to about 80,000, as determined by Gel Permeation Chromatography using polystyrene standards. The molecular weight distribution (Mw / Mn) of the crystalline resin may be, for example, from about 2 to about 6, in modalities from about 3 to about 4.

Any suitable surfactants may be used for the preparation of latex and wax dispersions according to the present disclosure. Depending on the emulsion system, any desired nonionic or ionic surfactants such as anionic or cationic surfactants may be contemplated.

Any suitable primer or primer mix can be selected in the latex process and in the toner process. In embodiments, the initiator is selected from known free radical polymerization initiators. The free radical initiator may be any free radical polymerization initiator capable of initiating a free radical polymerization process and mixtures thereof, such a free radical initiator being capable of providing free radical species upon heating to above 30 ° C.

More typical free radical initiators include, but are not limited to, ammonium persulfate, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, peroxide. dichlorobenzoyl, bromomethylbenzoyl peroxide, lauroyl peroxide, sodium persulphate, potassium persulphate, diisopropyl peroxycarbonate and the like.

Based on the total weight of the monomers to be polymerized, the initiator may be present in an amount from about 0.1% to about 5%, from about 0.4% to about 4%, from about from 0.5% to about 3%, although it may be present in larger or smaller quantities.

A chain transfer agent may optionally be used to control the degree of latex polymerization and to control the molecular weight and molecular weight distribution of the latex process product and / or the toner process according to with this disclosure. As may be appreciated, a chain transfer agent may become part of the latex polymer.

In embodiments, the chain transfer agent has a carbon-sulfur covalent bond. The carbon-sulfur covalent bond has an absorption peak in a wavelength region ranging from 500 to 800 cm -1 in an infrared absorption spectrum. When the chain transfer agent is incorporated into the latex and toner made from the latex, the absorption peak may be changed, for example, to a wavelength region of 400 to 4,000 cm -1.

Based on the total weight of the monomers to be polymerized, the chain transfer agent may be present in an amount from about 0.1% to about 7%, from about 0.5% to about 6%, from about 1.0% to about 5%, although it may be present in larger or smaller quantities.

In the latex process and the toner process of the disclosure, emulsification may be done by any suitable process such as mixing at elevated temperature. For example, the emulsion mixture may be mixed in a homogenizer defined at from about 200 to about 400 rpm and at a temperature from about 40 ° C to about 80 ° C for a period of about 1 min to about 20 ° C. min

Upon completion of the monomer addition, the latex may be allowed to stabilize by maintaining conditions for a period of time, for example, for about 10 to about 300 minutes, before cooling. Optionally, the latex formed by the above process may be isolated by standard methods known in the art, for example coagulation, dissolution and precipitation, filtration, washing, drying or the like.

The latex of the present disclosure may be selected for coalescence-aggregation-emulsion processes to form toners, inks and developers by known methods. The latex of the present disclosure may be melted in a mixture or otherwise mixed with various toner ingredients such as a wax dispersion, a coagulant, an optional silica, a charge reinforcing additive or an optional charge control additive. , an optional surfactant, an optional emulsifier, an optional flow additive and the like. Optionally, latex (e.g., around 40% solids) may be diluted to the desired solids charge (e.g., about 12% to 15% by weight solids) before formulated into a toner composition. .

Methods for making such latex resins may be performed as described in U.S. Patent No. 7,524,602, the contents of which are incorporated herein by reference in their entirety.

Various suitable known colorants, such as inks, pigments, ink mixtures, pigment mixtures, ink and pigment mixtures, and the like, may be included in the toner. The colorant may be included in the toner in an amount of, for example, from about 0.1% to about 35% by weight of the toner, from about 1% to about 15% of the toner, from about 3% to about 10% by weight of the toner, although amounts outside these ranges may be used.

As examples of suitable colorants, reference may be made to carbon black and the like. As colored pigments, cyan, magenta, yellow, red, green, brown, blue or their mixtures can be selected. Generally, cyan, magenta or yellow pigments or inks or mixtures thereof are used. The pigment or pigments may be dispersions of water based pigments.

In addition to the polymer binding resin, the toners of the present disclosure may also contain a wax, which may be either a single wax type or a mixture of two or more different waxes. A single wax may be added to toner formulations, for example, to improve specific toner properties such as toner particle shape, the presence and amount of wax on the toner particle surface, loading characteristics and / or fusion, glare, hollowness, offset printing properties and the like. Alternatively, a combination of waxes may be added to provide various properties for the toner composition.

When included, the wax may be present in an amount of, for example, from about 1 wt% to about 25 wt% of toner particles, in embodiments, from about 5 wt% to about 20% by weight of the toner particles.

Selectable waxes include waxes with, for example, a weight average molecular weight of from about 500 to about 20,000, in embodiments of from about 1,000 to about 10,000.

Toner particles may be prepared by any method within the skill of those skilled in the art. Although toner particle-related embodiments are described below with respect to emulsion aggregation processes, any suitable method of preparing toner particles may be used, including chemical processes such as suspension and encapsulation processes.

In embodiments, toner compositions may be prepared by emulsion aggregation processes, such as a process which includes adding a mixture of an optional wax or any other desired or required additives, and emulsions including the resins described above, optionally with surfactants as described above, and then coalesce the aggregate mixture. A mixture may be prepared by the addition of an optional wax or other materials, which may also optionally be dispersed (s), including a surfactant, to the emulsion which may be a mixture of two or more resin-containing emulsions. The pH of the resulting mixture may be adjusted with an acid (i.e., a pH adjuster) such as, for example, acetic acid, nitric acid or the like. In embodiments, the pH of the mixture may be adjusted to from about 2 to about 4.5. In addition, in embodiments, the mixture may be homogenized. If the mixture is homogenized, homogenization can be accomplished by mixing at about 600 to about 4,000 revolutions per minute (rpm). Homogenization can be performed by any suitable means, including, for example, an IKA ULTRA TURRAX T50 probe homogenizer or a Gaulin 15MR homogenizer.

After preparation of the above mixture, generally an aggregating agent may be added to the mixture. Suitable aggregating agents include, for example, aqueous solutions of a bivalent cation or a multivalent cation material. In the present embodiments, a polyaluminium halide, specifically polyaluminium chloride (PAC) is used. PAC is a stronger multivalent flocculant compared to aluminum sulphate, which is a bivalent flocculant. PAC has been found to interestingly improve surface morphology by reducing the amount of styrene acrylate on the surface. The multivalent PAC is believed to help connect and maintain the higher acidity styrene acrylate latex to the core of the toner particles.

By using the PAC, the manufacturing process is modified to lengthen the coalescence time (compared to that used with conventional flocculants such as aluminum sulfate) from about 1 hour to about 3 hours or about 1, 5 hours to about 2.5 hours.

It has been found that this modification of the longer coalescence time is necessary to smooth the toner surface and obtain optimal surface morphology.

Other aggregating agents that may be used include the corresponding bromide, fluoride or iodide and combinations thereof. In embodiments, the aggregating agent is present in the toner composition in an amount from about 0.1% to about 1.0%, or from about 0.2% to about 0.8%, or about 0%. 25% to about 0.5% by weight of the total weight of the toner particles. In embodiments, the aggregating agent may be added to the mixture at a temperature below the resin glass transition temperature (Tg). As discussed above, the reduced coalescing temperature used is preferably from about 70 ° C to about 90 ° C or from about 70 ° C to about 80 ° C or from about 70 ° C to about 77 ° C.

The aggregating agent may be added to the mixture to form a toner in an amount of, for example, from about 0.1 parts per hundred (pph) to about 1pph of the toner particles, in embodiments, of about. 0.25pph to about 0.75pph of the toner particles.

The brightness of a toner can be influenced by the amount of metal ion retained, such as Al3 +, in the particle. The amount of retained metal ion can be further adjusted by addition of ethylene diamino tetracetic acid (EDTA). In embodiments, the amount of metal ion retained, for example Al3 +, in toner particles of the present disclosure may be from about 0.1 pph to about 1pph, in embodiments, from about 0.25pph to about 0 8pph.

The disclosure also provides a melt blending process for the production of safe and low cost crosslinked thermoplastic connector resins for toner compositions, which have, for example, low attachment temperature and / or high displacement temperature, and which may have minimized or substantial vinyl offset. In the process, unsaturated base polyester resins or polymers are melt blended, i.e., in the molten state under high shear conditions producing substantially uniformly dispersed toner constituents, the process of which provides a resin and toner blend product with gloss properties. optimized. By "highly cross-linked," is meant that the polymer involved is substantially cross-linked, that is, at or above the gel point. As used herein, "gel spot" means the point where the polymer is no longer soluble in solution.

In order to control the aggregation and coalescence of the particles, in the embodiments the aggregating agent can be measured in the mixture over time. For example, the agent may be measured in the mixture over a period of about 5 to about 240 minutes, in modalities of about 30 to about 200 minutes. Addition of the agent may also be made while mixing is maintained under agitated conditions, in modalities from about 50 rpm to about 1,000 rpm, in modalities from about 100 rpm to about 500 rpm, and at a temperature which is below Tg of resin.

Particles may be allowed to aggregate until a predetermined desired particle size is obtained. A predetermined desired size refers to the desired particle size to be obtained as determined prior to formation, with the particle size monitored during the growth process as known in the art, until such particle size is reached. Samples can be taken during the growth process and analyzed, for example, with a Coulter Counter, for average particle size. In embodiments, the particle size may be from about 5.0 to about 6.0pm, from about 6.0 to about 6.5pm, from about 6.5 to about 7.0pm, about 7.0 at about 7.5pm.

Growth and molding of the particles after addition of the aggregating agent may be performed under any suitable conditions. For example, growth and shaping may be conducted under conditions where aggregation occurs separately from coalescence.

After aggregation to the desired particle size, with the optional formation of a layer as described above, the particles can then be coalesced to the desired final shape, the coalescence being achieved by, for example, heating the mixture to a temperature. from about 55 ° C to about 100 ° C, in embodiments, from about 65 ° C to about 75 ° C, which may be below the melting point of a crystalline resin to prevent plasticization. Higher or lower temperatures may be used, it being understood that temperature is a function of the resins used.

Coalescence may continue for a period of from about 0.1 to about 9 hours, in modalities of from about 0.5 to about 4 hours.

After coalescence, the mixture may be cooled to room temperature, such as from about 20 ° C to about 25 ° C. Cooling can be fast or slow as desired. A suitable method of cooling may include introducing cold water into a jacket around the reactor. After cooling, the toner particles can optionally be washed with water and then dried. Drying may be performed by any suitable method, for example, lyophilization.

[0048] Toners may have favorable loading characteristics when exposed to extreme RH conditions. The low humidity zone (zone C) can be about 129C / 15% RH, while the high humidity zone (zone A) can be about 28sC / 85% RH. Toners of the present disclosure may have a source-to-weight toner charge (Q / M) of from about -5 pC / g to about -80 pC / g in embodiments of about -10 pC / g about -70 pC / g and a surface additive after loading of final blend toner from -15 pC / g to about -60 pC / g, in embodiments of about -20 pC / g to about -55 pC / g.

In embodiments, a cover may be applied to the aggregate toner particles formed. Any resin described above as suitable for the core resin may be used as the cover resin. The cover resin may be applied to the aggregate particles by any method within the skill of those skilled in the art. In embodiments, the cover resin may be in an emulsion, including any surfactant described herein. The aggregate particles described above may be combined with said emulsion so that the cover is formed on the aggregate particles. In embodiments, an amorphous polyester may be used to form a layer over the aggregates to form toner particles having a core-layer configuration.

Toner particles may have a diameter size of from about 4 to about 8pm, in embodiments of from about 5 to about 7pm, the ideal cover component may be from about 26 to about 30% by weight. of toner particles.

Alternatively, a thicker cover may be desirable to provide desirable loading characteristics due to the larger surface area of the toner particle. Thus, the resin coating may be present in an amount from about 30% to about 40% by weight of the toner particles, in embodiments from about 32% to about 38% by weight of the toner particles. embodiments, from about 34% to about 36% by weight of the toner particles.

Once the desired final toner particle size is reached, the pH of the mixture can be adjusted with a base (e.g. a PH adjuster) to a value of about 6 to about 10, and by from about 6.2 to about 7. pH adjustment can be used to freeze, i.e. to stop toner growth. The base used to stop toner growth may include any suitable base, such as, for example, alkali metal hydroxides, such as, for example, sodium hydroxide, potassium hydroxide, ammonium hydroxide, combinations thereof and the like. In embodiments, EDTA may be added to help adjust the pH to the desired values noted above. The base may be added in amounts of from about 2 to about 25% by weight of the mixture, in embodiments of from about 4 to about 10% by weight of the mixture. In embodiments, the cover has a larger Tg than the aggregate toner particles.

Various suitable solid core materials or particles may be used for the carriers and developers of this disclosure. Characteristic core properties include those that, in embodiments, will allow toner particles to acquire a positive charge or a negative charge and carrier cores that allow desirable flow properties in the developer reservoir present in an electrophotographic imaging apparatus. Other desirable core properties include, for example, suitable magnetic characteristics that enable magnetic brush formation in magnetic brush development processes; desirable mechanical aging characteristics; and desirable surface morphology to allow high electrical conductivity of any developer, including the carrier and a suitable toner.

Examples of carrier particles or cores that may be used include iron or steel, such as atomized iron or steel powders available from Hoeganaes Corporation or Pomaton S.p.A (Italy); ferrite such as Cu / Zn-ferrite containing, for example, about 11% copper oxide, about 19% zinc oxide and about 70% iron oxide, including those commercially available from DM

Steward Corporation or Powdertech Corporation, Ni / Zn-ferrite available from Powdertech Corporation, Sr (strontium) ferrite, containing, for example, about 14% strontium oxide and about 86% commercially available iron oxide from Powdertech Corporation and Ba-ferrite; magnetites, including those commercially available from, for example, Hoeganaes Corporation (Sweden); nickel; their combinations and the like. Other suitable carrier cores may include granular zircon, granular silicon, glass, silicon dioxide, combinations thereof and the like. In embodiments, suitable carrier cores may have an average particle size of, for example, from about 20pm to about 400pm in diameter, in embodiments from about 40pm to about 200pm in diameter.

In embodiments, a ferrite may be used as the core, including a metal such as iron and at least one additional metal such as copper, zinc, nickel, manganese, magnesium, calcium, lithium, strontium, zirconium. , titanium, tantalum, bismuth, sodium, potassium, rubidium, cesium, strontium, barium, yttrium, lanthanum, hafnium, vanadium, niobium, aluminum, gallium, silicon, germanium, antimony, their combinations and the like.

In some embodiments, the carrier liner may include a conductive component. Suitable conductive components include, for example, carbon black.

There may be a number of additives added to the carrier. The filler additive components may be selected in various effective amounts, such as from about 0.5 wt.% To about 20 wt.%, From about 1 wt.% To about 3 wt. in the sum of polymer / copolymer weights, component conductor and other charge additive components. The addition of conductive components may act to further increase the negative triboelectric charge given to the carrier, and consequently further increase the negative triboelectric charge given to the toner in, for example, an electrophotographic development subsystem. Components can be included by roll mixing, falling, crushing, stirring, electrostatic powder cloud spraying, fluid bed, electrostatic disc processing, and an electrostatic curtain, and wherein the conveyor liner is fused to the conveyor core in a rotary kiln or passing through a heated extruder.

Conductivity may be important for the development of semiconductive magnetic brush to enable good development of solid areas that may otherwise be poorly developed. Addition of a polymeric coating of the present disclosure, optionally with a conductive component such as carbon black, may result in carriers with diminished triboelectric response with a relative humidity change of from about 20% to about 90%, in embodiments, of. about 40% to about 80%, which load is more consistent when the relative humidity is changed. Thus, there is less load reduction at high relative humidity reducing the toner background in prints and less load increase and subsequently less development loss at low relative humidity resulting in such image quality performance improvement due to higher density. optics.

As noted above, in embodiments the polymeric coating may be dried, and then may be applied to the core carrier as a dry powder. Powder coating processes differ from conventional solution coating processes. Solution coating requires a coating polymer whose molecular weight and composition properties allow the resin to be soluble in a solvent in the coating process. This requires relatively low Mw components compared to powder coating. The powder coating process does not require solvent solubility, but requires the resin coated as a particle with a particle size of from about 10nm to about 2pm, in embodiments, from about 30nm to about 1pm, in embodiments. about 50nm to about 500nm.

Examples of processes that may be used to apply the powder coating include, for example, combining the carrier core and resin coating material by cascade roller blending, falling, crushing, stirring, powder cloud spraying. electrostatic, fluidized bed, electrostatic disc processing, electrostatic curtains, their combinations and the like. When resin coated carrier particles are prepared by a powder coating process, most coating materials can be fused to the carrier surface, thereby reducing the number of toner impaction sites on the carrier. Fusion of the polymeric coating can occur by mechanical impaction, electrostatic attraction, their combinations and the like.

Following application of the resin to the core, heating may be initiated to allow the coating material to flow over the surface of the carrier core. The concentration of coating material, in modalities, dust particles and heating parameters may be selected to allow the formation of a continuous film of the coating polymers on the surface of the carrier core, or to allow only selected areas of the carrier core. are coated. In embodiments, the carrier with the polymeric powder coating may be heated to a temperature of from about 170 ° C to about 280 ° C, in embodiments of from about 190 ° C to about 240 ° C for a period of time. time, for example, from about 10min to about 180min, in embodiments, from about 15min to about 60min, to allow the polymer coating to melt and fuse with the carrier core particles. After incorporation of the powder on the surface of the carrier, heating may be initiated to allow the coating material to flow over the surface of the carrier core. In embodiments, the powder may be fused to the conveyor core either in a rotary kiln or by passing through a heated extruder apparatus.

In embodiments, the coating coverage comprises from about 10% to about 100% of the carrier core. When selected areas of the metal carrier core remain uncoated or exposed, the carrier particles may have conductive properties when the core material is a metal.

The coated carrier particles may then be cooled in room temperature modalities and recovered for use in developer training.

In embodiments, carriers of the present disclosure may include a core, in embodiments, a ferrite core, having a size from about 20pm to about 100μιτι, in embodiments, from about 30pm to about 75pm, coated from about 0.5% to about 10% by weight, in embodiments, from about 0.7% to about 5% by weight, of the polymer coating of the present disclosure, optionally including carbon black.

Thus, with the carrier compositions and disclosure processes of the present, there may be developers formulated with selected characteristics of high triboelectric loads and / or conductivity values using a number of different combinations.

The toner particles thus formed may be formulated into a developing composition. Toner particles can be mixed with carrier particles to achieve a two component developer composition. The developer toner concentration may be from about 1% to about 25% by weight of the total developer weight, in embodiments, from about 2% to about 15% by weight of the total developer weight.

Control [0068] Control Toner Example 1: Preparation of 22% Styrene Acrylate Core (162nm Latex Particle Size) Black Toner Particles at 70 ° C

[0069] in a 2L reactor, 43g of amorphous polyester emulsion (FXC42 available from Kao Corporation), 47g of amorphous polyester emulsion (FXC56 available from Kao Corporation), 81g of styrene acrylate latex (composed of 23, 5% n-butylacrylate, 76.5% styrene with an average molecular weight of 55,000 g / mol, 162nm particle size), 29g crystalline polyester emulsion, 43g wax, 9.6g cyan pigment, 57g Black pigment (Nipex-35), 0.7g of surfactant (Dowfax) and 534g of deionized water (Dl) water are combined. Then 2.7 g of aluminum sulfate (Al2 (SC> 4) 3) mixed with 33g of D1 water is added to the slurry under homogenization at 3000-4000 RPM. The reactor is set to 260 RPM and is heated to 42C to aggregate toner particles. When the size reaches 4.8-5pm, a cover coating is added consisting of 69g of amorphous polyester emulsion (FXC42), 74g of amorphous polyester emulsion (FXC56) with 1.15g of surfactant (Dowfax) and all pH adjusted to 3.3 using 0.3M nitric acid The reaction is further heated to 50 C. When the toner particle size reaches 5.6-6 microns, freezing begins with the slurry pH being adjusted to 4, 5 using a 4% NaOH solution. The reactor RPM is decreased to 220, followed by the addition of 5.77 grams of a chelating agent (Versene100) and more NaOH solution until the pH reaches 7.8. The reactor temperature is increased to 70 ° C. The pH of the slurry is maintained at 7.8 or higher up to 70 ° C. Once at the coalescing temperature, the pH of the slurry is reduced to 6.0 using pH 57 buffer and is coalesced for about 1 hour until particle circularity is between 0.955-0.960 measured by the particle flow image analysis instrument. (FPIA). The mud is then extinguished and cooled in 770g of Dl ice. The final particle size was 5.90 microns, GSDv 1.21, GSDn 1.22 and a circularity of 0.958. The toner is then washed and lyophilized.

Example 1 Toner Example 1: Preparation of AI2 Hybrid Black Toner Particles (S04) 3 In a 2L reactor, 43g amorphous polyester emulsion (), 47g amorphous polyester emulsion (FXC56 available from Kao Corporation), 82g styrene acrylate latex (23.5% n-butylacrylate compound, 76.5% styrene with average molecular weight 55,000 g / mol, 162nm particle size, 141nm particle size), 29g crystalline polyester emulsion, 43g wax, 9.6g cyan pigment, 57g black pigment (Nipex-35), 0.7g surfactant (Dowfax) and 534g deionized Dl water are combined. . Then 2.7 g of aluminum sulfate (Al 2 (SO 4) 3) mixed with 33 g of water D 1 is added to the slurry under homogenization at 3000-4000 RPM. The reactor is set to 260 RPM and is heated to 42C to aggregate toner particles. When the size reaches 4.8-5pm, a cover coating is added consisting of 69g of amorphous polyester emulsion (FXC42), 74g of amorphous polyester emulsion (FXC56) with 1.15g of surfactant (Dowfax) and all pH adjusted to 3.3 using 0.3M nitric acid The reaction is further heated to 50 C. When the toner particle size reaches 5.6-6 microns, freezing begins with the slurry pH being adjusted to 4, 5 using a 4% NaOH solution. The reactor RPM is decreased to 220, followed by the addition of 5.77 grams of a chelating agent (Versene100) and more NaOH solution until the pH reaches 7.8. The reactor temperature is increased to 70 ° C. The pH of the slurry is maintained at 7.8 or higher up to 70 ° C. Once at the coalescing temperature, the pH of the slurry is reduced to 6.0 using pH 57 buffer and is coalesced for about 1 hour until particle circularity is between 0.955-0.960 measured by the particle flow image analysis instrument. (FPIA). The mud is then extinguished and cooled in 770g of Dl ice. The final particle size was 6.0 microns, GSDv 1.21, GSDn 1.24 and a circularity of 0.955. The toner is then washed and lyophilized.

Example 2 Toner Example 2: Preparation of PAC Hybrid Black Toner Particles

In a 2L reactor, 43g of amorphous polyester emulsion (FXC42), 47g of amorphous polyester emulsion (FXC56), 82g of styrene acrylate latex (23.5% n-butylacrylate compound, 76, 5% styrene with an average molecular weight of 55,000 g / mol, 141nm particle size, 141nm particle size), 29g crystalline polyester emulsion, 43g wax, 9.6g cyan pigment, 57g black pigment ( Nipex-35), 0.7g surfactant (Dowfax) and 534g deionized water D1 are combined. Then 2.7 g of polyaluminium chloride (PAC) mixed with 24 g of 0.02 M nitric acid is added to the slurry under homogenization at 3000-4000 RPM. The reactor is set to 260 RPM and is heated to 42C to aggregate toner particles. When the size reaches 4.8-5pm, a cover coating is added consisting of 69g of amorphous polyester emulsion (FXC42), 74g of amorphous polyester emulsion (FXC56) with 1.15g of surfactant (Dowfax) and all pH adjusted to 3.3 using 0.3M nitric acid The reaction is further heated to 50 C. When the toner particle size reaches 5.6-6 microns, freezing begins with the slurry pH being adjusted to 4, 5 using a 4% NaOH solution. The reactor RPM is decreased to 220, followed by the addition of 5.77 grams of a chelating agent (Versene100) and more NaOH solution until the pH reaches 7.8. The reactor temperature is increased to 70 ° C. The pH of the slurry is maintained at 7.8 or higher up to 70 ° C. Once at the coalescing temperature, the pH of the slurry is reduced to 6.0 using pH 57 buffer and is coalesced for about 2 hours until particle circularity is between 0.955-0.960 measured by the particle flow image analysis instrument. (FPIA). The mud is then extinguished and cooled in 770g of Dl ice. The final particle size was 6.3 microns, GSDv 1.23, GSDn 1.25 and a circularity of 0.955. The toner is then washed and lyophilized.

[0076] Comparative Examples [0077] Xerox 700 Toner (Cyan or Black) [0078] This commercially available toner has been used compared to the inventive toner. The Xerox 700 Toner is made up of an emulsion aggregation toner, in which the core is comprised of about 6 to 7 weight percent of crystalline resin, 5 to 6 weight percent of cyan or black pigment, 8 to 10 weight percent. percent by weight of wax and from about 50 to about 52 percent by weight of amorphous polyester resin, and in which the cap is about 28 percent by weight of toner [0079] Xerox Docucolor 2240 Cyan Toner [0080] ] This commercially available toner has been used compared to the inventive toners. The Xerox Docucolor 2240 Toner is made up of an emulsion aggregation toner in which the core is comprised of about 5 to 6 weight percent cyan or black pigment, 10-12 weight percent wax, and about 54 to 56 weight percent styrene acrylate resin, and in which the cover is a styrene acrylate resin of about 28 weight% toner.

Table 1 shows the characteristics and properties of the Control, Toner Examples 1 and 2, as well as an aggregate emulsion polyester based toner (Xerox 700 Toner). Control and Toner Examples 1 and 2 all incorporate at least 20% styrene acrylate latex. The toner example 2 has PAC as the flocculant.

Table 1 SEM images were taken from the control and toner examples 1 and 2 as shown in Figure 1. As can be seen from Figure 1, the surface improves with smaller size polystyrene / acrylate latex (the Control in Comparison with Toner Example 1) and even greater improvement is seen when the flocculant is changed to PAC (Toner Example 2).

These toners were then analyzed for loading and fusing performance, the results are below.

[0084] Developer Performance Results [0085] Loading performance is comparable to standard EA polyester toner, however, the main concern is start lock and% heat cohesion. These two properties are not as good as Polyester Control Toner, however, after some investigation it was found that the surface morphology of the toners was worse than Polyester Control Toner. As can be seen from the SEM toner images, the toner surface contained a large amount of polystyrene / acrylate latex and some wax particles. The wax content is typical; however, surface polystyrene / acrylate prevents toner additives from forming properly by covering the toner surface and also negatively affects toner performance. Surprisingly, when the flocculant was switched to PAC to flocculate the toner, it can be seen that the toner surface improves. Polystyrene / acrylate latex does not protrude onto the toner surface but remains predominantly in the center of the toner.

Table 2 Table 3 below shows the toner lockout results for the various hybrid examples. The lock for Toner Example 2 is within the experimental Polyester Control Toner error (Xerox Toner 700); Assuming the previous two samples (the control and the toner example 1) have noticeable gaps.

[0087] Figure 2 shows how the% heat cohesion of the toner of the present embodiments is also improved compared to the Toner 1 control and example, without the PAC as the flocculant.

[0088] Summary of Fusion Results [0089] Brightness, crease, and hot particle offset printing data were collected with Color Xpressions Select (90 gsm) fused samples using an internal fusion equipment. The toners were within the experimental uncertainty of the polyester control toner reference samples.

The Control [0091] Print brightness curve of this hybrid toner was among the Xerox 700 Toner, Xerox Docucolor 2240 comparative reference samples and has a lower peak brightness (57 gu versus 63 gu). The temperature required to reach 50 units of brightness is 158QC while Xerox Docucolor 2240 toner required 166SC and polyester control toner needed 146QC.

Minimum Hold Temperature (MFT) The minimum hold temperature of this hybrid toner was lower than the Xerox 700 Toner (117QC versus 123QC) and much lower than the Xerox Docucolor 2240 Toner (117QC versus 143QC). Laboratory scale and reference scale particles may have smaller crease fixation MFTs than production scale particles.

[0093] There was no hot toner offset printing for the 210SC fuser roll resulting in wide fusing latitude.

[0094] Example 1 and 2 Toner [0095] This hybrid toner's print brightness approaches the projected brightness and the reference range of the polyester and crease-fixing MFT is smaller than the MFT's toner production MFT. polyester. Both hybrid toners have a very low crease fixation MFT and gloss curve approaching the gloss curve of polyester toner. The smaller coalescence curve and small styrene acrylate latex particles had no significant impact on the fusion performance of the hybrid design.

Fusion results were consistent with previous hybrid particles.

Claims (10)

1. Toner composition, characterized in that it comprises: toner particles having a core, wherein core comprises a resin; a colorant; a wax, and polyaluminium chloride, wherein the resin comprises a styrene acrylate resin, a crystalline polyester resin and an amorphous polyester resin; and a cover arranged over the core. Toner composition according to claim 1, characterized in that the aggregating agent is present in the toner composition in an amount from about 0.1% to about 1.0% by weight of the total weight of the toner. Toner particles. Toner composition according to claim 1, characterized in that the styrene acrylate resin is present in the core in an amount of from about 5% to about 30% by weight of the total core weight. Toner composition according to claim 1, characterized in that the crystalline polyester resin in the core is present in an amount of from about 5% to about 8% by weight, by total toner weight, and wherein the amorphous core polyester resin is present in an amount of from about 20% to about 30% by weight of the total weight of the toner composition. Toner composition according to claim 1, characterized in that the amorphous resin in the cover is present in an amount of from about 30% to about 36% by weight of the toner composition. Toner composition according to claim 1, characterized in that it has a minimum melting temperature of about 100 ° C to about 130 ° C. Toner composition according to claim 1, characterized in that it has a dielectric loss of about 20 to about 40. 8. Developer, characterized in that it comprises: a toner composition; and a toner carrier, wherein the toner composition comprises toner particles having a core, wherein the core comprises a resin; a colorant; a wax, and polyaluminium chloride, wherein the resin comprises a styrene acrylate resin, a crystalline polyester resin and an amorphous polyester resin; and a cover arranged over the core. A toner making method comprising: mixing and emulsifying together a resin, a colorant and a wax, wherein the resin comprises a styrene acrylate resin, a crystalline polyester resin to form a latex emulsion. ; adding polyaluminium chloride to the latex emulsion; aggregating the latex emulsion to form toner particle cores, wherein the toner particle cores comprise styrene acrylate resin, crystalline polyester resin and amorphous polyester; form a cover over the toner particle cores to form toner particles; coalescing toner particles; and cool the toner particles. Method according to claim 9, characterized in that the polyaluminium chloride is added to the latex emulsion at a temperature below the glass transition temperature (Tg) of the styrene acrylate resin and crystalline polyester resin.