CN1130767A - Two component type developer, developing method and image forming method - Google Patents

Abstract

A two-component type developer for developing an electrostatic image is constituted by at least a toner and a magnetic carrier. The toner has a weight-average particle size D4 of at most 10 mu m and a number-average particle size D1 satisfying D4/D1</=1.5. The magnetic carrier comprises composite particles comprising magnetic iron compound particles, non-magnetic metal oxide particles, and a binder comprising a phenolic resin. The composite particles contain the magnetic iron compound and the non-magnetic metal oxide in a total proportion of 80-99 wt. %. The magnetic iron compound particles have a number-average particle size ra, and the non-magnetic metal oxide particles have a number-average particle size rb satisfying rb/ra>1.0.

Description

Two-component developer, developing method and formation method

The present invention relates to a kind of two-component developer that in fields such as electrophotography and xerox, is used for electrostatic image, developing method and formation method.

So far, in U.S. Pat 2,297,691; 3,666,363; Various electrophotographic methods are disclosed in 4,071,361 grades.In these methods, by the light image of irradiation, in photoconductive layer, form electrostatic latent image corresponding to the original, develop this sub-image on the sub-image thereby again toner is attached to.If necessary, then on being transferred to such as the transfer materials of paper after, by heating, pressurization or heating and pressurization or with solvent vapo(u)r the toner image that obtains is fixed up, obtain copy or folder.

In the step of development sub-image, by utilizing the electrostatic interaction of electrostatic latent image, charged toner-particle forms toner image.Usually, in the method for the developing electrostatic latent image that uses toner, comprise that the two-component developer of toner and carrier mixture is suitable for obtaining the panchromatic copy or the printed matter of high image quality.

In recent years, along with the development of computer technology, high-definition television technology etc., require to have the equipment of output high resolving power full-colour image.For this purpose, people attempt to provide a kind of comparing with the silver halide photography image to have high-quality and high-resolution toner full-colour image.In order to satisfy these needs, people have carried out various researchs aspect method and developer.

About the example of developer aspect, representative trial is to use toner and the carrier with small particle diameter.Yet, use the toner of small particle diameter to increase powder-processed and electrofax performance optimization aspect for example except developing, the difficulty aspect transfer printing and photographic fixing.Therefore, only has certain limitation by improving the quality that toner improves image.

On the other hand, as in the improved trial aspect the electrophotographic method,, can obtain high-quality image by making the magnetic brush enrichment on developer-carrier band parts such as development sleeve.Consider from the method aspect, the enrichment of magnetic brush can by develop between a part of magnetic pole in development sleeve or in development sleeve the less magnetic pole of working strength realize.These measures can suppress the influence of magnetic brush, but owing to can not fully suppress developer, also can encounter difficulties, as scattering and relatively poor conveying function.So can not simply adopt these.The enrichment of magnetic brush also can be realized by using particle diameter magnetic carrier particle less or that magnetic force is lower.

For example Japanese patent application JP-A-59-104663 proposes to use the magnetic carrier with low saturation magnetization.If use carrier granular simply with low saturation magnetization, line reproducibility may get a new look, but, because the constraint of magnetic carrier particle has reduced on development sleeve, is easy to produce magnetic carrier and transfers to the phenomenon that is referred to as " carrier adheres to " that causes the image spots on the photosensitive drum.

We also know, when using the less magnetic carrier of particle diameter, carrier also takes place easily adhere to.For example, Jap.P. IP-B-5-8424 proposes to use less toner and the magnetic carrier of particle diameter, carries out untouchable development under the vibration electric field.In this Japanese patent specification, also described magnetic carrier and in the developing process that uses the vibration electric field, improved the effect that carrier adheres to effectively with higher electric resistivity.Have been found that in some cases, use magnetic carrier to be not enough to improve carrier and adhere to obtain high-quality image, even particularly have exposing under the surperficial situation very much of small scale of low-resistance carrier core with high electrical resistance.In the untouchable developing method of this employing, when magnetic carrier has been provided the bigger magnetization on magnetic pole, can obtain the image that goodish image color does not have carrier to adhere to acquisition, but when the magnetization of magnetic carrier reduced, image color can descend obviously.

Generally, magnetic resin carrier has than the higher specific insulation of carrier that ferrocart core or metal oxide core (as the core of ferrite, tri-iron tetroxide) are arranged.Under situation about using (as described in raising be to realize) by the magnetic material that use has a different-grain diameter ratio as the magnetic resin carrier of the magnetic material that allows to contain the raising amount, if the inner magnetic material that adds comprises the magnetic material with low-resistivity, then can provide higher flux about power.Yet when these magnetic carriers were used in the developing process that uses alternating magnetic field, it was not enough to improve adhering to of carrier under its a little situations.

As mentioned above, prevent from simultaneously adhering to of carrier to adopt various measures for obtaining high image quality, but also need to provide a kind of developer of the two-component-type that can address the above problem.

Therefore, the purpose of this invention is to provide a kind of two-component developer that can address the above problem.

A further object of the present invention provides a kind of developer of two-component-type, and it can be got rid of carrier and adhere to and prevent or suppress image blurring generation, thereby a kind of high-quality toner image is provided.

Another object of the present invention provides a kind of developer of two-component-type, and it can prevent the scattering of toner effectively.

Another object of the present invention provides a kind of developer of two-component-type, and it has the life-span of prolongation, and only causes the decline of very little image quality in the duplicating of a large amount of paper or printing.

Another object of the present invention provides a kind of developing method and formation method that uses above-mentioned developer.

According to the present invention, a kind of two-component developer that shows rest image is provided, it comprises at least a toner and a kind of magnetic carrier, wherein:

The weight average particle diameter D of toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5; With

Magnetic carrier contains composite particles, and this particle contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contains the cementing agent of phenolics; The overall ratio that contains the composite particles of Armco magnetic iron compound and nonmagnetic metal oxide is 80-99wt%; The number average bead diameter of Armco magnetic iron compound particle is r _a, the number average bead diameter of nonmagnetic metal oxide is r _b, satisfy r _b/ r _a＞1.0.

Press another aspect of the present invention, a kind of method of developing electrostatic image is provided, comprise the steps:

Utilize above-mentioned two component-type developers of component carrier tape of the carrier band developer that field generator for magnetic wherein is housed;

On developer carrier band element, form the magnetic brush of two-component developer;

Magnetic brush is contacted with the sub-image display element;

Developing electrostatic image on the image development element forms toner image, applies alternating electric field to developer carrier band element simultaneously.

Press another aspect of the present invention, a kind of formation method is provided, wherein repeat above-mentioned steps respectively with at least a magenta developer, blue developer and the yellow developer that satisfy above-mentioned two-component developer requirement, peony toner image, cyan toner image, the yellow toner image with gained forms full-colour image at least.

In conjunction with the accompanying drawings, according to the description of the preferred version below of the present invention, these and other purpose of the present invention, feature and advantage will become more apparent.

Fig. 1 is the synoptic diagram of equipment of implementing the scheme of developing method of the present invention.

Fig. 2 is the figure that describes the equipment of the resistivity be used for measuring magnetic carrier, carrier core and metal oxide.

Fig. 3 is the synoptic diagram of equipment of implementing the scheme of formation method of the present invention.

Fig. 4 is the sectional view of the magnetic carrier slug particle of a scheme among the present invention, and wherein nonmagnetic metal oxide (haematite) particle has precedence over the surface that ferromagnetic metal oxide (magnetic iron ore) particle is positioned at the core grain.

In the present invention, above-mentioned purpose is by realizing that with two-component developer toner and the magnetic carrier of developer all improve.

As the result that we study in great detail, disclosed and applying in the situation of alternating magnetic field, the carrier in the contact videograph process adheres to driving force and is injected from development sleeve magnetropism carrier by electric charge as governing factor when applying the development bias voltage and causes. Repeatability about the point in the digital sub-image, the decline of having found the repeatability of point is because the friction on magnetic carrier and photosensitive drum surface causes the electrostatic latent image charge leakage on photosensitive drum to cause, so the point of digital sub-image is broken to shape heterogeneous. Even have in use in the situation of support core of high volume resistance, for example be dispersed with in the resin carrier situation of magnetic material, if magnetic material has low resistivity as magnetic iron ore, then electric charge can be sewed via magnetic-particle.

In order to address these problems simultaneously, the present invention has used the magnetic carrier that contains composite particles, so that composite particles contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contains the binding agent of phenolic resins; Composite particles contains Armco magnetic iron compound and nonmagnetic metal oxide, and its total amount ratio is 80-99wt%; The number average bead diameter r of Armco magnetic iron compound particle_a, the number average bead diameter r of nonmagnetic metal oxide_b, satisfy r_b/r _a＞1.0. The nonmagnetic metal oxide particle that consequently resistivity is higher preferentially is positioned at the surface of carrier granular, thereby effectively improves the resistivity of carrier. Owing to this reason, developer of the present invention is preventing that charge injection from preventing that to carrier neutralization carrier from adhering to that to reproduce truly electrostatic latent image be effective.

By making the nonmagnetic metal oxide particle preferentially be positioned at the surface of carrier surface or core, rather than in center or the inside of carrier granular, can provide ratio resistance higher when being exposed to carrier or core surperficial than magnetic iron oxide composition granule at carrier surface, therefore effectively prevent the injection of electric charge.

Repeatability as for the scattering that prevents image blurring and toner and improvement final image mid point, by making the nonmagnetic metal oxide particle with relatively big particle diameter preferentially be positioned at the surface, then provide small heterogeneity on the surface of magnetic carrier particle, thereby carried better toner-particle. Utilize this improvement and the improvement aspect toner, can improve the charging of toner and the picture quality of final image after the transfer printing after the development in being right after electrophotographic processes and the photographic fixing step.

By using weight average particle diameter D₄Be 10 μ m to the maximum and by satisfying D₄/D ₁Be 1. 5 number average bead diameter D to the maximum₁The toner that the steep particle diameter of representative distributes and comprise and contain the magnetic iron oxide composition granule and by the magnetic carrier of the composite particles of phenolic resin bonded nonmagnetic metal oxide particle can provide can not producing of a kind of two-component-type the image blurring or scattering and obtain the developer of good some repeatability of mixing colours. This point is possible, because by making toner particle diameter distribution narrow, the toner triboelectric charge distributes and done steep, and since in triboelectrification charged composite particles small surperficial heterogeneity is provided, the band electric energy of toner is finished better.

Because as follows, toner of the present invention is not perishable, and can provide continuously similar to high-quality image of initial period.

Consider developer and in long-term use procedure, go bad because of the damage of toner and magnetic carrier, this damage mainly be since in imaging container the shearing of the magnetic force between toner and carrier or between carrier granular or gravity shear action cause. Toner has consumed basically, and magnetic carrier is reused, and does not consume, so that the damage that causes on the surface has accumulated.

Yet, if comprising the carrier of the composite particles that is formed by Armco magnetic iron compound, nonmagnetic metal oxide and phenolic resins uses together in conjunction with the toner with steep particle diameter distribution, can reduce in the magnetic force shearing force between toner and the carrier and between the carrier granular, thereby reduce the damaged surfaces of carrier granular.

Especially, the magnetic carrier particle that uses in the present invention provides the fine grain surperficial heterogeneity that comprises magnetic-particle and nonmagnetic metal oxide particle, so that when the magnetic carrier particle is wrapped up by resin, bonding between magnetic carrier particle (slug particle) and wrapped resin is improved, and has suppressed the decortication of wrapped resin layer.

From the viewpoint of higher picture quality, the small size of magnetic carrier is preferred, but according to the relation of magnetic force and particle diameter, it is easy to increase carrier and adheres to. In conjunction with these viewpoints, the number average bead diameter scope of the magnetic carrier that uses in the present invention can be 1-1000 μ m, and preferred 1-300 μ m are to provide high picture quality. Prevent and prevent the viewpoint that developer is rotten from what high image quality, carrier adhered to, number average bead diameter is that 5-100 μ m are more suitably during continuous imaging. If the number average bead diameter of magnetic carrier surpasses 1000 μ m, the specific area of magnetic brush of photosensitive drum of then rubbing can reduce, thus be not easy to provide the toner of q.s, and stay the scratch of magnetic brush, from the viewpoint of high concentration and high image quality, this is undesirable. Have number average bead diameter less than the magnetic carrier of 1 μ m since each carrier granular be easy to cause that than small particle diameter carrier adheres to. Here the method for the measurement magnetic carrier grain diameter of institute's foundation will be described below.

As for the magnetic properties of the magnetic carrier that uses among the present invention, use to have saturation magnetization (σ_s) be 10-80emu/cm³Magnetic carrier may be suitable. It is 15-60emu/cm that further preferred use has saturation magnetization³Magnetic carrier. The intensity of magnetization of magnetic carrier can suitably be selected according to the particle diameter of carrier. Although also be subjected to the impact of particle diameter, have above 80emu/cm³The magnetic carrier of the intensity of magnetization be easy to cause have low-density and comprising that the development sleeve of the development electrode of rigidity ear shape (ear) forms magnetic brush, therefore, be easy in the toner image of gained, cause scratch, and be easy to cause image deflects, for example semi-tone image roughening, irregular with solid picture, particularly owing to going bad in the continuously long-time imaging on a large amount of paper. If at 10emu/cm³Below, so that the magnetic force deficiency that magnetic carrier produces can cause toner to adhere to or reduce the performance of the transmission of toner.

Here the magnetic properties of indication is the numerical value that uses the magnetic properties self recording apparatus (" BHV 1 " can be buied from Riken Denshi K.K) of an oscillating magnetic flux field pattern to record. The actual conditions of measuring will be described below.

The magnetic carrier that uses in the present invention is 5 * 10 in electric-field intensity preferably⁴Have at least 1 * 10 under the V/m¹²The resistivity of ohmcm. If resistivity is lower than 1 * 10¹²Ohmcm is because the charge leakage of sub-image is easy to cause above mentioned carrier to adhere to and reduces some repeatabilities in developing process. Here the method for the resistivity of the mensuration magnetic carrier of indication will be described below.

The Armco magnetic iron component that consists of the core of magnetic carrier preferably include ferrous metal alloy, exhibit magnetic properties by formula M OFe₂O ₃Or MFe₂O ₄Magnetic iron ore or the ferrite of representative, wherein M represents the metal of divalence or monovalence, such as Mn, Fe, Ni, Co, Cu, Mg, Zn, Cd or Li. M can be one or more metals. Concrete example can comprise alloy, such as silicon steel, permalloy, sendust, Fe-Co and alnico alloy; And the iron-based oxide material, such as magnetic iron ore, r-iron oxide, Mn-Zn-based ferrite, Ni-Zn-based ferrite, Mn-Mg-based ferrite, Li-based ferrite and Cu-Zn-based ferrite. In these materials, magnetic iron ore is preferred the use.

In the present invention the Armco magnetic iron component of Shi Yonging preferably saturation magnetization be at least 30emu/g's.

The example of nonmagnetic metal oxide can comprise one or more metals, as Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Ba and Pb.The object lesson of nonmagnetic metal oxide comprises: AL ₂O ₃, SiO ₂, CaO, TiO ₂, V ₂O ₅, CrO ₂, MnO ₂, Fe ₂O ₃, CoO, NiO, ZnO, SrO, Y ₂O ₃And ZrO ₂

Above-mentioned Armco magnetic iron compound and nonmagnetic metal oxide can preferably be dispersed in and form the carrier slug particle in the resin.Under this condition, preferably use multiple particle with analogous shape, think bonding that enhancing is provided and higher support strength.The example of preferred compositions can comprise: magnetic iron ore and haematite (α-Fe ₂O ₃), magnetic iron ore and r-Fe ₂O ₃, magnetic iron ore and SiO ₂, magnetic iron ore and Al ₂O ₃, magnetic iron ore and TiO ₂, and magnetic iron ore and Cu-Zn-based ferrite.In these combinations, consider the intensity of price and gained carrier, the combination of magnetic iron ore and haematite is preferred.

Armco magnetic iron compound and nonmagnetic metal oxide are being disperseed to form in the resin under the situation of carrier core, and the number average bead diameter of Armco magnetic iron compound particle is r _a, the number average bead diameter of nonmagnetic metal oxide particle is r _b, satisfy ratio r simultaneously _b/ r _aSurpass 1.0.If ratio equals 1 or less than 1, the Armco magnetic iron compound particle with low resistivity is exposed to the surface easily, thus can not obtain carrier raising resistivity and prevent that carrier from adhering to.Bigger r _b/ r _aRatio is preferred, makes bigger nonmagnetic metal oxide particle appear at the surface of carrier granular, can prevent that electric charge from injecting carrier, has therefore prevented because the carrier that the sub-image charge leakage causes adheres to and put repeatability decline.Be effect that the resistivity that improves magnetic carrier is provided and the good combination of strengthening the intensity of carrier, r _b/ r _aRatio is 1.2-5.0 to be preferred.Above preferred particle diameter ratio ranges be based on following discovery: when the filler particles blending simultaneously of different-grain diameter be dispersed in when forming carrier (core) particle in the resin, the particle of greater particle size preferentially is positioned at the surface of carrier (core).Therefore, the particle with nonmagnetic metal oxide of higher electric resistivity should have the particle diameter bigger than Armco magnetic iron compound particle, and this point is very important.The number average bead diameter r of Armco magnetic iron compound _aCan preferred 0.02-5 μ m, it can be according to the change of size of carrier.The number average bead diameter r of nonmagnetic metal oxide particle _bBe preferably 0.05-10 μ m.The method of used here mensuration metal oxide particle diameter will be described below.

By at carrier (core) particle surface, rather than select to form nonmagnetic metal oxide particle layer in that carrier granular is inner, make the injection that resistivity preferably may be provided and can suppress electric charge effectively.

More particularly, the cumulative volume that appears at the Armco magnetic iron compound particle of inside, carrier (core) particle cross section is Pa ₁, the cumulative volume of nonmagnetic metal oxide particle is Pb ₁, the cumulative volume that appears at the Armco magnetic iron compound particle of carrier (core) particle surface is Pa2, the cumulative volume of nonmagnetic metal oxide particle is Pb ₂, preferred Pb ₁/ Pa ₁＜1, Pb ₂/ Pa ₂＞1, thus higher resistivity obtained.

About being dispersed in the resistivity of Armco magnetic iron compound and nonmagnetic metal oxide used in the resin, the resistivity of preferred Armco magnetic iron compound particle is at least 1 * 10 ³Ohmcm, the resistivity of nonmagnetic metal oxide particle preferably is higher than the resistivity of Armco magnetic iron compound.The resistivity at least 10 of nonmagnetic metal oxide particle more preferably ⁸Ohmcm.If the resistivity of magnetic-particle is lower than 1 * 10 ³Ohmcm even reduce the dispersion amount of Armco magnetic iron compound, also is difficult to obtain the resistivity of necessity of carrier, therefore, is easy to cause that electric charge injects, and causes relatively poor picture quality and cause carrier adhering to.If the resistivity of the metal oxide that particle diameter is bigger is lower than 1 * 10 ⁸Ohmcm is difficult to fully improve the resistivity of carrier core, therefore, is difficult to obtain above mentioned effect.The method of the resistivity of used here mensuration metal oxide will be described below.

Magnetic carrier contains Armco magnetic iron compound and the nonmagnetic metal oxide that total amount is 80-99wt%.If total amount is lower than 80wt%, carrier (core) particle is easy in the shaping particles process, is particularly directly assembling mutually in the polymerization process.This will cause the instability of size distribution, and can not realize good electrification by friction.When being higher than 99wt%, resulting support strength descends, and is easy to take place the problem as the carrier fragmentation during the continuous imaging on a large amount of paper.

In order to reach effect of the present invention better, in the resin carrier that contains the Armco magnetic iron compound that is in disperse state and nonmagnetic metal oxide, the amount of nonmagnetic metal oxide particle preferably accounts for 5-70wt% of the total amount of Armco magnetic iron compound and nonmagnetic metal oxide particle.If be lower than 5wt%, just be difficult to improve the resistivity of carrier (core), be higher than 70wt%, the magnetic carrier of gained only has less magnetic force, adheres to so be easy to cause carrier.

Preferably has 1.0-2.0g/cm by magnetic carrier of the present invention ³Bulk density.If be lower than 1.0g/cm ³, because the influence of magnetic force is easy to produce carrier and adheres to.And be higher than 2.0g/cm ³, resulting developer is also because the influence of the magnetic force of magnetic carrier is apt to deteriorate during continuous imaging on a large amount of paper.The measurement of the bulk density of magnetic carrier can be undertaken by JIS K5101.

In the present invention, magnetic carrier can use phenolics to constitute as binding resin.

Be used for magnetic carrier of the present invention, for example, can make polymerization of mixtures directly produce a carrier core material again and prepare by mix monomer (being a kind of binding resin precursor), Armco magnetic iron compound and nonmagnetic metal oxide.The monomer that is used for polymerization can comprise the combination of phenol and aldehyde.More particularly, to contain phenolic resin cured carrier (core) particle in order producing, can to make a kind of phenol, aldehyde, Armco magnetic iron compound and nonmagnetic metal hopcalite under the condition that has base catalyst and dispersion stabilizer in aqueous medium, to exist, stand suspension polymerization.In order to obtain the magnetic carrier of high resistivity, preferably form composite particles by the two-stage polymerization method, wherein, for shaping particles, at first make the Armco magnetic iron compound stand polymerization and form slurries, then, the adjuvant of monomer, nonmagnetic metal oxide and other any necessity added to carry out the second step polymerization in the slurries, perhaps carry out three steps of repetition above-mentioned steps or the rapid polymerization process of multistep more.Example as the phenol of monomer can comprise phenol, resorcinol; Alkylphenol, as metacresol, p-t-butyl phenol, o-propylphenol, and alkylphenol and their derivant.In the middle of them, because shaping particles feature and expense, phenol is particularly preferred.

Cover on it in order to strengthen the carrier core and to be convenient to resin, phenolics can be crosslinked.

It is suitable that the magnetic carrier that is used for the present invention can be preferably a kind of usefulness, the form that the coating resin of selecting by the chargeding performance of toner used among the present invention covers.This coating can be finished by the resin that use contains the nonmagnetic metal oxide particle, with the resistivity of control carrier core with improve the slickness of magnetic carrier.This magnetic carrier with resin-coating can prevent effectively that electric charge from injecting magnetic carrier inside, prevents that carrier from having too high resistivity and magnetic carrier that too much electric charge is arranged, thereby stablize the triboelectric charge of toner.Being dispersed in nonmagnetic metal oxide in the coating resin can contain one or more and be selected from above mentioned metal oxide.The further preferred SiO that uses with good fluidity ₂, Al ₂O ₃, TiO ₂Or α-Fe ₂O ₃, or utilize in the carrier core used nonmagnetic metal oxide to improve the bonding of coating resin.The overlay capacity of this coating material based on the weight of carrier core, can be 0.5-10wt%, particularly 0.6-5wt%.

If coating amount is lower than 0.5wt%, is difficult to cover effectively carrier slug particle and control and makes it charged ability with coating resin friction toner.If surpass 10wt%, because too high resin-coating rate, resistivity can be in the scope of hope, but may cause lower mobile and the image spots occurring behind the continuous imaging on a large amount of paper.

Coated with resins used in this invention can be an insulating resin, and it can be thermoplasticity or thermoset resin.The example of thermoplastic resin can comprise polystyrene, and acryl resin is as poly-methyl methacrylate and styrene-propene acid copolymer; Styrene-Butadiene, vinyl-vinyl acetate copolymer, polyvinylidene chloride resin, vinyl acetate resin, polyvinylidene fluoride resin, fluorocarbon resin, full fluorocarbon resin, the full fluorocarbon resin of solvent soluble, polyvinyl alcohol (PVA), Pioloform, polyvinyl acetal polyvinylpyrrolidone, petroleum resin, cellulose; Cellulose derivative is as cellulose acetate, nitrocellulose, methylcellulose, Carboxymethyl Cellulose, hydroxyethyl cellulose and hydroxypropyl cellulose; Novolac resin, low molecular weight polyethylene, saturated alkyl vibrin; The aryl vibrin is as polyethylene terephthalate, polybutylene terepthatlate and polyarylate; Polyamide, polyacetal resin, polycarbonate resin, polyethersulfone resin, polysulfone resin, polyphenylens sulfide resin and polyether ketone resin.

The example of thermoset resin (or curable resin) can comprise: phenolics, phenol-formaldehyde resin modified, maleic resin, alkyd resin, epoxy resin, acryl resin, the unsaturated polyester (UP) that is obtained by maleic anhydride, terephthalic acid (TPA) and polyvalent alcohol polycondensation, urea resin, melmac urea-melmac, xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, aetoguanamine resin, glyptal resin, furane resin, polyorganosiloxane resin, polyimide resin, polyamide-imide resin, polyetherimide resin and polyurethane.

Thermoplasticity above-mentioned or thermoset resin can use separately or with the form of potpourri.The resin that also can make the potpourri of thermoplastic resin and curing or rigidizer obtain solidifying.

The magnetic carrier that applies can be preferably by coated with resins solution is sprayed onto be in suspend or carrier (core) particle of fluidized state on, and at slug particle surface formation coat film, or spray drying is produced.

Other painting method can be included under the condition that applies shearing force, and the solvent under the condition that has metal oxide to exist in the coated with resins solution evaporates gradually.More particularly, solvent evaporation can be carried out under the temperature that is higher than the coated with resins vitrifying point, and then, resulting agglomerating metal oxide particle is spread out.In addition, can under heating, solidify at the back coat film that spreads out.

Metal oxide can have the particle shape that is used for employed toning system of suitable selection.Yet, be used for metal oxide of the present invention and can preferably have and be 2 sphericity to the maximum.If sphericity surpasses 2, gained developer flowability is relatively poor, and the magnetic brush shape that provides is bad, so be difficult to obtain high-quality toner image.The carrier sphericity is with such measurement, for example use field-emission scanning electron microscope (as " S-800 " that buys from Hitachi K.K) to get 300 carrier granulars at random, measure the sphericity mean value that defines by following equation with image analyzer (as " Luzex 3 " buied from Nireco K.K):

Sphericity (SF1)=[(MXLNG) ²/ AREA] * π/4, MXLNG represents the maximum gauge of carrier granular here, AREA represents the projected area of carrier granular, when sphericity near 1 the time, its shape approximation sphere.

Weight average particle diameter (the D that is used for toner of the present invention ₄) be 10 μ m to the maximum, preferred 3-8 μ m.Weight average particle diameter (D importantly ₄) and number average bead diameter (D ₁) ratio (D ₄/ D ₁) be 1.5 to the maximum.

If the weight average particle diameter (D of toner ₄) surpassing 10 μ m, the particle of toner that then shows electrostatic latent image is too big so that can not demonstrate sub-image truly, and the toner scattering takes place easily.

If weight average particle diameter (D ₄) to number average bead diameter (D ₁) ratio (D ₄/ D ₁) greater than 1.5, can make toner that wide CHARGE DISTRIBUTION is arranged, therefore, be easy to generate such as charged failure and toner particle grain size deviation.The weight average particle diameter of toner and number average bead diameter can be used as the Coulter counter and measure.Its details are described in the back.

Be used for toner of the present invention and can comprise binding resin, the example of described resin comprises: polystyrene; The polymkeric substance of styrene derivative is as poly-right-chlorostyrene and polyvinyl toluene; Styrol copolymer, as styrene-right-chloro-styrene copolymer, styrene-ethylene base toluene multipolymer, styrene-ethylene base naphthalenedicarboxylate copolymer, multipolymer, Styrene-Butadiene, styrene-isoprene multipolymer and the styrene-acrylonitrile-indene copolymer of copolymer in cinnamic acrylic ester, styrene-methacrylate ester copolymer, styrene-α-chlorine methylmethacrylate multipolymer, styrene-acrylonitrile copolymer, styrene-ethylene ylmethyl ketone; Maleic acid resin, acryl resin, methacrylic resin, polyvinyl acetate, the silicone resin of Polyvinylchloride, phenolics, natural or phenol-formaldehyde resin modified, natural or modification; Has the vibrin that is selected from aliphatic polyol, aromatic polyol or bis-phenol and aliphatic dicarboxylic acid or aromatic dicarboxylic acid structural unit; The petroleum resin of polyurethane resin, polyamide, polyvinyl butyral, terpene resin, coumarone-indene resin and cross-linked resin, described crosslinked resin such as styrene base resin and crosslinked polyester resin also can use.

Can comprise vinyl monomer for obtaining the comonomer that styrol copolymer is used in combination with styrene monomer, it comprises: acrylic acid, acrylate or derivatives thereof, as methyl acrylate, ten diacrylate ethyl esters, butyl acrylate, dodecyl acrylate, 2-ethyl hexyl acrylate, acrylic acid (2-ethylhexyl) ester, phenyl acrylate, methyl methacrylate, Jia Jibingxisuanyizhi, butyl methacrylate, 2-Propenoic acid, 2-methyl-, octyl ester, vinyl cyanide, methacrylonitrile and acrylamide; Maleic acid; Maleic acid half ester and diester are as maleic acid butyl ester, maleic acid methyl esters and dimethyl maleate; Vinyl esters, as vinylacetate and vinyl chloride; Vinyl ketone is as ethenyl methyl ketone and vinyl hexyl ketone; Vinyl ether, as vinyl methyl ether and ethylene ethyl ether.

Crosslinking chemical can consist predominantly of the compound of at least two polymerizable double bonds.Its example has: aromatic divinyl compound, as: divinylbenzene and divinyl naphthalene; The carboxylate that two two keys are arranged is as ethylene glycol diacrylate, Ethylene glycol dimethacrylate and dimethacrylate (1,3 butylene glycol) ester; Divinyl compound, as divinyl aniline, divinyl ether, divinyl sulfide and divinylsulfone; With the compound that the two keys of three or more alkene are arranged.These compounds can use separately or with form of mixtures.When synthesizing these binding resins, be benchmark with the binding resin, the preferred 0.01-10wt% of the consumption of crosslinking chemical, further preferred 0.05-5wt%.

Under the situation of working pressure photographic fixing system, but binding resin can be used for a kind of toner of pressure photographic fixing, the example of described resin comprises: tygon, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, vinyl-vinyl acetate copolymer, ionomer resin, Styrene-Butadiene, styrene-isoprene copolymerization, thing linear saturated polyester, paraffin and other wax.

In the present invention, toner can use in conjunction with charge control agent, and charge control agent mixes (joining inside) toner-particle or and toner-particle blending (joining the outside).Owing to added charge control agent, can realize the suitableeest electric charge control according to the use toning system.The example of positive charge control agent comprises: nigrosine and its product with the fatty acid metal salts modification; Quaternary ammonium salt is as tributyl benzyl sodium-1-hydroxyl-4-naphthalene sulfonate and tetrabutyl ammonium tetrafluoroborate salt; Two organotin oxides are as two basic olefinic oxides, dioctyltin oxide, dicyclohexyl tin-oxide; Dibutyl tin borate, dioctyl tin borate and dicyclohexyl tin borate.These compounds can be separately or in conjunction with two or more uses.In these compounds, be particularly preferred based on the compound and the quaternary ammonium salt of nigrosine.

In addition, in the present invention, also can use negative charge controlling agent, as organic slaine, organometallic complex and chelate.Wherein, cetylacetone metallic complex (derivant that replaces with dialkyl group that comprises that monoalkyl replaces), salicylic acid metal complex (derivant that replaces with dialkyl group that comprises that monoalkyl replaces) and its corresponding salt are preferred.Salicylic acid is particularly preferred for the metal complex on basis or based on the slaine of salicylic acid.The instantiation of preferred negative charge control agent comprises: the complex or the salt of the complex of aluminium acetylacetonate, ferric acetyl acetonade (II), 3,5-two-tert-butyl salicylic acid chromium or salt and 3,5-two-tert-butyl zinc salicylate.

When adding toner inside to, with respect to the binding resin of per 100 weight portions, the preferable amount ratio of above-mentioned charge control agent is 0.1-20 weight portions, preferred especially 0.2-10 weight portions.When being used for colour imaging, preferably use charge control agent colourless or light color.

As the colorant of toner, can use known so far dyestuff and/or pigment.Its example comprises: carbon black, phthalocyanine blue, peacock blue, permanent red, C lake red CAN'T, rhodamine color lake, hansa yellow, permanent yellow and benzidine yellow.Per relatively 100 weight portion binding resins, the addition of colorant is 0.1-20 weight portions, preferred 0.5-20 weight portions.In order to obtain to have the fixedly toner image or the ohp film of good transparency, the binding resin of per relatively 100 parts of weight portions, the addition of colorant preferably is 12 weight portions to the maximum, further preferred 0.5-9 weight portions.

The toner that constitutes developer by the present invention can further comprise wax, as tygon, low-molecular-weight polypropylene, microcrystalline wax, Brazil wax, sasoe wax, paraffin, to improve the release performance when the hot pressing photographic fixing.

Be used for toner of the present invention and use as potpourri with the fine powder that add the outside suitably, fine powder comprises inorganic material, as the fine grained of silica, aluminium oxide and titanium dioxide; Organic material is as the fine grained of teflon, Kynoar, polymethylmethacrylate, polystyrene and silicone resin.If these fine powders are the outsides of adding toner to, fine powder will be between toner and carrier granular, or exists between the toner-particle, so developer will have the life-span of improved flowability and raising.The preferred mean grain size of above-mentioned fine powder is maximum 0.2 μ m.If mean grain size surpasses 0.2 μ m, mobile improvement effect is deficiency, and in some cases develop or transfer printing during because mobile not enough, picture quality will descend.The method of measuring the particle diameter of these fine powders will be described later.

These fine powders preferably have 30m at least ²The specific surface area of/g, particularly 50-400m ²The specific surface area of/g, specific surface area is measured with the nitrogen adsorption method.Fine powder is suitably to add with respect to every 100wt part toner 0.1-20wt part.

By the present invention, binding resin, colorant, non-essential charge control agent and other adjuvant of vinyl-type or non-vinyl-type thermoplastic resin can fully blending in mixer in the preparation of the toner that constitutes developer, then, knead with hot kneading unit fusion, compatibly to mediate resin and to disperse or dissolve pigment and dyestuff as warm-up mill, kneading machine or extruder.With the product cooling curing of so mediating, pulverizing, classification obtain toner-particle.For with the toner classification, preferred many calibration of utilizing inertial force (coanda effect) (stage equipment of multi-division) that uses.Utilize such equipment, can produce toner effectively with the size distribution that limits by the present invention.

So the toner-particle that obtains can use with the form that they exist, but preferred and use with the form of potpourri by the fine powder of above-described adjuvant outside.

The mixing of toner and fine powder can use the mixing machine as the Henschel mixer to carry out.Resulting toner and the magnetic carrier mixing that has outside additive obtains two-component developer.In two-component developer, toner preferably accounts for 1-20wt%, more preferably accounts for 1-10wt%, and in typical situation, it depends on developing process.Toner in two groups of type developers can be provided 5-100 μ c/g suitably, most preferably the triboelectric charge of 5-60 μ c/g, the assay method of the triboelectric charge of indication will be described below here.

Use the developing method of two-component developer of the present invention, for example, can use developing apparatus shown in Figure 1 and finish.Preferably, under the state as photosensitive drum 3, under the condition of using alternating electric field, develop at magnetic brush contact sub-image display element.

The exchange electric field preferably has peak-to-peak voltage and is 500-5000 volts, and frequency is 500-10000Hz, preferred 500-3000Hz, and it can suitably be selected according to process.Waveform can suitably be selected, as triangular wave, square wave, sine wave or by changing the waveform that dutycycle obtains.If the voltage of using is lower than 500 volts, in some situation, is difficult to obtain enough image colors, and reclaims unsatisfactorily at the image blurring toner of non-image areas.If be higher than 5000 volts, in some cases, sub-image can be disturbed by magnetic brush, thereby reduces the quality of image.

Frequency is lower than 500Hz, in some cases, can cause electric charge to inject carrier, because carrier adheres to the quality that can reduce image with the sub-image interference.If be higher than 10000Hz, toner is difficult to catch up with electric field, therefore, is easy to reduce picture quality.

In developing method of the present invention, being preferably magnetic brush on the development sleeve 1 that has photosensitive drum 3, to set a contact width (developing gap) C be 3-8mm, develops and enough image colors and good some repeatability are provided to finish, and do not cause that carrier adheres to.If developing gap C is narrower than 3mm, the then difficult requirement of satisfying enough image colors and good some repeatability.If the wide 8mm that crosses is difficult to then fully prevent that carrier from adhering to.Developing gap C can suitably regulate by the gap B that changes the distance A between developer regulating element 2 and the development sleeve 1 and/or change between development sleeve 1 and the photosensitive drum 3.

By using at least 3 corresponding to magenta, cyan and yellow developing apparatus, adopt developer of the present invention and developing method, and in conjunction with the preferred developing system that adopts the display digit sub-image, formation method of the present invention can form the full-colour image very relevant with the medium tone repeatability effectively, make true development become possibility, avoid the negative effect of magnetic brush and the interference of sub-image simultaneously in a sub-image.Use has the toner of steep size distribution, in follow-up transfer step, is realizing that aspect the high transfer printing ratio also be effective.Therefore, obtain high image quality at half tint and solid image section and become possibility.

Except that the first step in imaging has the high image quality,, use two-component developer of the present invention also can avoid effectively reducing picture quality behind the continuous imaging on a large amount of paper owing to the shearing force on the developer that acts in the developer container is less.

For full-colour image clearly is provided, preferably use four developing apparatuss corresponding to magenta, cyan, yellow and black, finish black at last and develop.

A kind of imaging device that is suitable for implementing full color imaging method of the present invention is described with reference to Fig. 3.

The color electronography equipment that is shown in Fig. 3 is divided into transfer materials (copy paper)-translator unit I that extend to central authorities on the right side (right side of Fig. 3) that comprises transfer drum 315 and slave unit master component 301 roughly, sub-image near transfer drum 315 configurations forms part II and developing apparatus III (promptly rotating developing apparatus).

Transfer materials-translator unit I constitutes like this: on the right side wall of equipment master component 301, form an opening, dispose transfer materials supply dish 302 and 303 by this opening is removable imperially, and a part is stretched out this assembly.Paper (transfer materials)-donor rollers 304 and 305 be configured in the dish 302 and 303 directly over.Link to each other with 305 with paper donor rollers 304,, make that it can be by the direction rotation of arrow A, configuration paper donor rollers 306, paper supply orientation spare 307 and paper supply orientation spare 308 at its left side configuration transfer drum 315.Near the neighboring of transfer drum 315, the arranged in order that is from upstream to the downstream by sense of rotation is to supporting roller (abutting roller) 309, glipper 310, transfer materials separating charger 311 and disengaging pawl 312.

In transfer drum 315, transfer printing charger 313 and transfer materials separating charger 314 are installed.That part that transfer materials centers on the transfer drum 315 provides a transfer paper (not shown) that adheres to, and transfer materials is attached on it owing to static.In the upper right side of transfer drum 315, travelling belt 316 is installed near disengaging pawl 312, at end (right side) configuration one fixing device 318 of the transfer printing direction of travelling belt 316.One taking-up dish 317 is installed in the downstream of fixing device, and this disc portion ground extends and removable turning up the soil stretched out master component 301.

Sub-image forms part II and constitutes like this: photosensitive drum (as the OPC photosensitive drum) contacts with the periphery surface of transfer drum 315 as being configured to its periphery surface along the sub-image display element of the rotation of direction as shown in the figure.Discharge charger 320 is set above contiguous photosensitive drum 319, is from upstream to the downstream along photosensitive drum 319 sense of rotation clearer 321 and main charger 323 are set.In addition, also configuration comprises the image exposing apparatus as the reflection unit 325 of laser instrument 324 and mirror class, to be used for forming electrostatic latent image at the outer periphery surface of photosensitive drum 319.

The developing apparatus III of rotation constitutes like this: in the position relative with photosensitive drum 319 one rotatable chamber (being called rotating element later on) 326 is set.In rotating element 326, one four colour pattern developing apparatus radially is set to the quartern goes out the electrostatic latent image that on photosensitive drum 319 outer peripheral surfaces, forms to manifest (promptly developing).Four colour pattern developing apparatuss comprise yellow developing apparatus 327Y, magenta developing apparatus 327M, cyan developing apparatus 327C and black developing device 327BK.

The whole operation step of above-mentioned imaging device will be described with the pattern of full-colour image.When photosensitive drum 319 when the direction of arrow is rotated, drum 319 is charged by main charger 323.In equipment as shown in Figure 3, the peripheral translational speed of respective element, particularly photosensitive drum 319 (being called " process speed " later on) can be at least 100mm/sec (as 130-250mm/sec).After photosensitive drum 319 is by main charger 323 chargings, photosensitive drum 329 utilizes by the laser of modulating from the yellow image signal of the original 328 and exposes with imaging mode, on photosensitive drum, form corresponding sub-image, then, sub-image is shown by the yellow developing apparatus 327Y by rotating element 326 positioning of rotating, forms yellow toner image.

The transfer materials of sending into through paper supply orientation device 307, paper donor rollers 306 and paper donor rollers 308 (as common paper) is regularly picked up by glipper 310, and by means of to support roller 309 and be centered around on the transfer drum 315 supporting the electrode that roller 309 is oppositely arranged.Transfer drum 315 rotates synchronously with photosensitive drum 319 in the direction of arrow A, and the yellow toner image that is formed by yellow developing apparatus is transferred on the transfer materials on to low position in that the periphery surface of photosensitive drum 319 and transfer drum 315 is relative because of the action of transfer printing charger 313.Transfer drum 315 is further rotated prepares a kind of color (being magenta) under the transfer printing under the situation of Fig. 3.

On the other hand, photosensitive drum 319 is removed electric charge by discharge charger 320, and it is clean by cleaning doctor or cleaning device 321 cleanings, charged by main charger 323 again, then based on the exposure of ensuing magenta color image signal, thereby formed corresponding electrostatic latent image, when on photosensitive drum 319, forming electrostatic latent image by exposure based on the magenta signal, rotating element 326 rotation is so that the developing location that magenta developing apparatus 327M is positioned to stipulate, thereby finishes development with magenta toner.Next, for cyan and black repeat said process respectively, finish the transfer printing of four colour toners images.After this, the developed image of four kinds of colors on the transfer materials is recharged device 322 and 314 discharges (removing electric charge), discharge from the sorption state by glipper 310, separate from transfer drum by disengaging pawl 312, deliver to fixing device 318 through travelling belt 316 again, here the toner image of four kinds of colors fixes under heating and pressure.Therefore, a series of panchromatic printing or image-forming step have just been finished, and the full-colour image of regulation is provided on the one side of transfer materials.

In addition, the toner image of respective color can disposablely be transferred on the intermediate transfer element, and being transferred to then will be by on the transfer materials of photographic fixing.

The fixation rate of fixing device (as 90mm/sec) is slower than the circumferential speed (as 160mm/sec) of photosensitive drum.This is in order to provide enough heats to remove the molten image that mixes also loose two to four kinds of toner layers.Therefore, by to carry out photographic fixing, can provide the heat of increase to toner image than the slower speed of developing.

The measuring method of used here various character is described now.

1) magnetic carrier particle diameter

From sample carrier, get 300 particles (diameter is 0.1 μ m or bigger) at least at random, observation by light microscope by 100-5000 enlargement factors, utilize image dissector (as " Luzex3; " buy by Nireco K.K.) measure the horizontal FERE diameter of each particle as particle diameter, size distribution and number average bead diameter have been obtained like this based on number, thus, calculate base particle ratio in half the scope that size mostly is number average bead diameter most.

2) magnetic properties of magnetic carrier:

By utilizing periodic polarity magnet type magnetic self recording apparatus (" BHV-30 " can buy from Riken Denshi) to record.Magnetic carrier is placed in the external magnetic field of 10 kilo-oersteds, under this state, measures its saturation magnetization.Especially, enough to be filled into a volume densely be Ca.0.07cm to the magnetic carrier powdered sample ³The cylindrical plastic box in so that carrier granular does not cause the motion of carrier in moving, under this state, record magnetic moment, the sample volume of filling divided by reality obtains the intensity (magnetization) of unit volume.

3) resistivity of mensuration magnetic carrier

Carrier resistivity is to measure with equipment (chamber) E as Fig. 2, and this equipment is furnished with lower electrode 21, upper electrode 22, insulator 23, reometer/24, voltage table 25, stabilized voltage supply 26 and guided rings 28.In order to measure, the Ca.1g support samples 27 of packing among the E of chamber, electrode 21 and 22 contacts and applies betwixt voltage with it, measures the electric current that flows through at this moment, calculates resistivity.Because magnetic carrier is a powder type, avoid because the variation of the resistivity that the variation of occupied state causes so be careful.Resistivity as described herein is to measure under such condition: the contact area=ca.2.3cm between carrier 27 and electrode 21 or 22 ², carrier thickness=ca.2mm, the weight=180g of upper electrode 22, institute's making alive=100 volts.

4, the particle diameter of Armco magnetic iron compound and nonmagnetic metal oxide:

By 5, take a picture for the sample metal oxide powder with transmission electron microscope (" H-800 " can buy from Hitachi Seisaknsho K.K) under 000-20,000 times the enlargement factor.From photo, be taken to few 300 particles (diameter 0.01 μ m or bigger) at least at random and analyze, record the horizontal FERE diameter of each particle with image analyzer (" Luzes 3 " can be buied from Nireco).Calculate number average bead diameter from the measured value of at least 300 sample particles.5, there is ratio between Armco magnetic iron compound and the nonmagnetic metal oxide:

Can measure as follows in the magnetic carrier granule interior with at the Armco magnetic iron compound on magnetic carrier particle or slug particle surface and the ratio that exists between the nonmagnetic metal oxide.

Can solidify again and fix by carrier granular or carrier slug particle are distributed in the epoxy resin, and the support samples that slicer (as " FC4E ", can buy from REICHER-JUNG) will be embedded in the resin is cut off preparation carrier slice sample.

Select the particle section at random, by scanning electron microscope (" S800 ", can buy from Hitachi Seisakushok.k) 5,000-20, observe under 000 the enlargement factor and photograph, and analyze the particle section taken a picture with image analyzer (" Lnzex 3 " can be buied from Nireco K.K), measure the horizontal FERE diameter D in each discrete particles cross section.Suppose that Armco magnetic iron compound particle and nonmagnetic metal oxide particle are spherical, the volume of each discrete particles is counted π D3/6.In the section of each particle, its interior zone is defined as from the center to the radius * 0.3 zone, and the zone, top layer is defined as from radius * 0.95 to radius * 1.0 zone.For each carrier (core) particle, appear at the Armco magnetic iron compound particle of related particle section interior zone and nonmagnetic metal oxide particle at per unit area (μ m ²) on cumulative volume calculated, and represent with pa1 and pa2 respectively, appear at the Armco magnetic iron compound particle in zone, top layer and nonmagnetic metal oxide particle at per unit area (μ m ²) on cumulative volume also calculated respectively, and to represent to be worth pa1, pb1, pa2 and pb2 with pa2 and pb2 be the mean value of using corresponding to 20 carriers (core) particle, thinks to calculate ratio pa1/pb1 and pa2/pb2.

6), the resistivity of Armco magnetic iron compound and nonmagnetic metal oxide

The measurement that is similar to above mentioned carrier resistivity is measured.Sample compound or metal oxide are placed between the electrode 21 and 22 in the chamber shown in Figure 2 and uniform contact with it, under this state, apply a voltage between two electrodes, measure the electric current by therebetween, the calculated resistance rate.In order to guarantee the uniform contact of sample and electrode, back and forth rotate lower electrode 21 during filling sample.Value described herein is based under the following conditions measured value, fills metal oxide and interelectrode contact area S=ca.2.3cm ², thickness of sample d=ca.2mm, the weight=180g of upper electrode 22, institute's making alive=100 volts.

7), the particle diameter of toner

In 100-150ml electrolyte solution (1%-NaCl aqueous solution), add 0.1-5ml surfactant (alkyl benzene sulfonate) and 2-20mg sample toner.The sample dispersion that is suspended in the electrolytic liquid was handled 1-3 minutes, then, sample liquids is sent into caliber size is, for example (" Multisizer " can be from Coulter electronics Inc for the Coultor counter of 17 μ m or 100 μ m, buy) in, obtain in the scope of 2-40 μ m size distribution, calculate size distribution, number average bead diameter (D with PC based on number according to this distribution based on volume ₁) and weight average particle diameter (D ₄).

8, triboelectric charge

Weighing toner and magnetic carrier obtain containing the potpourri of 5wt% toner, and this potpourri mixed 60 seconds with the Turbula mixer.Gained mixture of powders (developer) is placed in the bottom and is equipped with in the canister of 500 orders conduction sieve, starts air exhauster and aspirates under the swabbing pressure of 250mmHg, makes the toner in the developer select to be removed by sieve.According to the weight difference before and after the suction and be connected to the voltage that obtains in the capacitor on the container, and calculate the triboelectric charge Q of toner according to following equation:

Q(μC/g)＝(C×V)/(W ₁－W ₂)

W wherein ₁Be the weight before aspirating, W ₂Be the weight after the suction, C is the electric capacity of capacitor, and V is the electromotive force reading of capacitor.

To describe the present invention according to embodiment below, used " part " refer to component " weight portion ".

Embodiment 1

10 parts of phenol

6 parts of formalin

(contain the formaldehyde of ca 40wt%, the methyl alcohol of ca 10wt%, all the other are water)

31 parts of magnetic iron ore

(Armco magnetic iron compound, d _Av(mean grain size)=0.24 μ m, Rs (resistivity)=5 *

10 ⁵Ohm.cm) α-Fe ₂O ₃(haematite) 53 parts

(nonmagnetic metal oxide, dav=0.6 μ m, Rs=8 * 10 ⁹Ohm.cm)

Above material, 4 parts of 28wt% ammoniacal liquor (base catalyst) and 15 parts of water are placed in the flask, under agitation mix, and be heated to 85 ℃ in 40 minutes, deposit 3 hours in and be cured reaction under this temperature.Content is cooled to 30 ℃, adds 100 parts of water, removes supernatant liquor, and precipitation washes with water and at air drying.Dried precipitation further at 50-60 ℃ and the driest under the decompression of the highest 5mmHg, obtains the spherical magnetic carrier slug particle that contains magnetic iron ore and haematite in phenolic resin adhesive, the Rs=8.0 of carrier slug particle * 10 ¹²Ohm.cm.

The magnetic carrier slug particle carries out surface applied with heat-curable silicone resin as follows.For obtaining the resin coating rate of 1.0wt%, preparation contains the toluene solution of carrier application of resin 10wt%.Add the carrier slug particle in this solution, the gained potpourri heats with evaporating solvent under the shearing force effect, provides overlay on the carrier core.Gained coating magnetic carrier particle solidified 1 hour at 250 ℃.Separate reunion then and cross 100 purposes sieve, obtain the magnetic carrier particle of coating, its number average bead diameter (D ₁) be 43 μ m, sphericity (SF1) is 1.04.

The resistivity Rs of the magnetic carrier of coating is 9 * 10 ¹³Ohm.cm, saturation magnetization σ _sBe 28emu/g.

The character of the magnetic carrier of coating is listed in the table 1 of back.

On the other hand, toner prepares as follows.

Yellow toner

100 parts in vibrin

(polycondensation products of bis-phenol and formic acid)

C.I. pigment yellow (colorant) is 4.5 parts

The salicylic Cr of two-tert-butyl cooperates 4 parts of salt

(negative charge controlling agent, light color)

These materials are fully blending in advance, and fusion is kneaded, and cooling also tentatively is broken into ca.1-2mm size particles with hammer-mill.Product is pulverized with the air-jetting type flour mill then, powder Ellow Jet classifier, the yellow powder that recovery can be electronegative (non magnetic yellow tone agent).

The titanium oxide fine powder of above-mentioned Yellow toner of 100wt part and the hydrophobization of 0.8wt part is blending mutually in the Henschel mixer, obtains having the outside titanium oxide fine powder Yellow toner that adds.Weight average particle diameter (the D of described Yellow toner ₄) be 8.6 μ m, number average bead diameter (D ₁) be 6.5 μ m, (D ₄/ D ₁) ratio is 1.32.When measuring together with the magnetic carrier of the coating for preparing previously, the triboelectric charge of toner (TC) is-27.1 μ C/g (toner concentration is 5wt%).

Magenta toner

100 parts in vibrin

(same Yellow toner)

C.I. dyestuff is red 122 4 parts

12 1 parts of C.I.Basic Red

Two-tert-butyl salicylic acid Cr cooperates 4 parts of salt

By the identical mode of preparation Yellow toner with above-mentioned material preparation can be electronegative magenta powder (non magnetic pinkish red toner).

The titanium oxide fine powder of the above-mentioned magenta toner of 100wt part and 8.0wt part hydrophobization is blending mutually in the Henschel mixer, obtains having the magenta toner of the outside titanium oxide fine powder that adds.The D of described magenta toner ₄=8.4 μ m, D ₁=6.5 μ m, D ₄/ D ₁=1.29.When measuring together with the magnetic carrier of the coating for preparing previously, the triboelectric charge of toner (TC) is-25.3 μ C/g.

Cyan toner

100 parts in vibrin

(same Yellow toner)

5 parts of copper-phthalocyanine dyes

Two-tert-butyl salicylic acid Cr-cooperates 4 parts of salt

By the identical mode of preparation Yellow toner with above-mentioned material preparation can be electronegative cyan powder (non magnetic cyan toner).

100 parts the above-mentioned cyan toner and the titanium oxide fine powder of 0.8 part of hydrophobization be blending mutually in the Henschel mixer, obtains the cyan toner with the outside titanium oxide fine powder that adds.Described cyan toner D ₄=8.6 μ m, D ₁=6.4 μ m, D ₄/ D ₁=1.34, when measuring together with the magnetic carrier of the coating for preparing previously, the triboelectric charge of toner (TC) is-27.8 μ C/g.

Black toner

100 parts in vibrin

(same Yellow toner)

5 parts of carbon blacks

(most of particle diameter=60nm)

4 parts of two-tert-butyl-salicylic acid Cr-complex salts

By with the identical mode of preparation Yellow toner prepare can be electronegative black powder (non magnetic black toner).

100wt. the titanium oxide fine powder of the hydrophobization of part above-mentioned black toner and 0.8wt. part is blending mutually in the Henschel mixer, obtains having the black toner of the outside titanium oxide fine powder that adds.Described black toner D ₄=8.4 μ m, D ₁=6.5 μ m, D ₄/ D ₁=-1.29.When measuring together with the magnetic carrier of the coating for preparing previously, the triboelectric charge of toner (TC) is-26.3 μ C/g.

The toner of the magnetic carrier of the coating of above-mentioned preparation and each color of above-mentioned preparation mixes, and makes two-component developer, and each all has toner concentration is 8.0wt.%.Two-component developer is packed in the panchromatic laser copier (" CLC-500 ", by Canon K, K makes) of remodeling, and each has as shown in Figure 1 developing apparatus described remodeling duplicating machine.Referring to Fig. 1, each developing apparatus is design so all, gap A between developer carrier band element (development sleeve) 1 and developer regulating element (magnetic scraper) 2 is 600 μ m, and the gap B between development sleeve and the electrostatic latent image display element (photosensitive drum) 3 is 500 μ m.At this moment developing gap c is 5mm.Development sleeve 1 and photosensitive drum 3 are driving in 1.75: 1 with peripheral speed ratio.The s1 of development sleeve is designed to provide the magnetic field of one 1 kilo-oersted, development conditions comprises that the peak of square wave oscillation electric field and peak-to-peak voltage are 2000 volts, frequency is 2000Hz, the development bias voltage is-470 volts, toner development back-pressure (Vcont) is 325wdy, it is 100 volts that blurred picture is removed voltage (Vback), and the main charging voltage on the photosensitive drum is-750 volts.Digital sub-image on photosensitive drum 3 under this development conditions demonstrates by the discharged-area development pattern.

Consequently, gained show high solid section image color (with the cyan toner image section measured be representative) image do not have the point of chap, do not have image fault or image blurring in image-region or non-image areas.

On 30,000 paper, carry out continuous full color imaging.After this, carry out image detection with the method that is similar to the first step.The solid image table of cyan toner reveals high concentration, and the middle tone color table reveals good repeatability.In addition, do not find that image blurring and carrier adheres to.Behind continuous imaging, observe blue developer with SEM (scanning electron microscope), do not observe the phenomenon of peeling off of application of resin on the carrier, what see is the excellent surface state that is similar to original coating magnetic carrier surface.

It the results are shown in the table 2 of back.

Embodiment 2

10 parts of phenol

6 parts of formalin (with embodiment 1)

44 parts of magnetic iron ore (with embodiment 1)

α-Fe ₂O ₃(with embodiment 1) 44 parts

Except that the consumption that changes base catalyst and water, make the above-mentioned material polymerization with the mode that is similar to embodiment 1.With the gradation after the polymerization, obtain the Magnaglo carrier core that disperses.The resistivity (Rs) of the carrier core of gained is 5.2 * 10 ¹²Ohm.cm.

To be 7/3 application of resin potpourri with styrene-propene acid resin/fluorine resin apply in the mode identical with embodiment 1 with the coating ratio of 1.0wt% slug particle.

The D of the magnetic carrier particle of coating ₁=55 μ m, sphericity (SF1) is 1.06.

Rs=8.0 * 10 of the carrier granular of coating ¹³Ohm.cm, σ _s=39emu/g.

So four kinds of toner blending of coating magnetic carrier that obtains and preparation in embodiment 1 make four kinds of two-component developers, and the toner concentration of each is 7wt.%.When being when measuring under the 5wt.% in toner concentration, it is yellow that the triboelectric charge of each toner is respectively :-30.2 μ C/g, magenta :-28.7 μ C/g, cyan :-32.9 μ C/g, and black :-29.8 μ C/g.

Developer installs in the imaging device identical with embodiment 1, and is used for developing under the identical development conditions.Its result is similar to embodiment 1, and the image table that is become for the first time reveals the repeatability of good point and fine rule and high resolution, and carrier does not adhere to.The result of full color imaging shows on 30,000 paper continuously, and image is very similar to the quality of imaging for the first time.In continuous imaging, do not observe carrier and adhere to, the same good when the surface of carrier is with the first time behind the continuous imaging.

Embodiment 3

Be equipped with the magnetic carrier core with following material by the two-stage polymerization legal system.

The first step

8 parts of phenol

4.8 parts of formalin (with implementing 1)

75 parts of magnetic iron ore (with embodiment 1)

Second step

2 parts of phenol

1.2 parts of formalin (with implementing 1)

α-Fe ₂O ₃(with embodiment 1) 9 parts

Except that the consumption that changes base catalyst and water, carry out first step polymerization by being similar to embodiment 1, in the gained slurries, inject the above-mentioned material that was used for for second step and carry out similar suspension polymerization, obtain polymer beads.With the polymer beads classification to obtain being dispersed with the resin carrier slug particle of Magnaglo.These slug particles show Rs=7.4 * 10 ¹²Ohm.cm.By sem observation, the slug particle cross section as shown in Figure 4, magnetite ore particles is present in inside, bigger α-Fe ₂O ₃Particle is present in the surface.Armco magnetic iron compound/nonmagnetic metal oxide exists ratio pb1/pa1=0, pb2/pa2=19.3 in the slug particle.

The slug particle application of resin coating identical with embodiment 1, but coating rate difference is 1.3wt.%.

The D of coating magnetic carrier particle ₁=40 μ m, sphericity (SF1) is 1.11.

Rs=3.5 * 10 of coating carrier granular ¹³Ohm.cm, σ _s=68emu/g.

So toner blending of four kinds of colors of preparation among coating magnetic carrier that obtains and the embodiment 1, the developer of four kinds of two-component-types of preparation, the concentration of the toner of each is 8wt.%.The triboelectric charge of each toner is yellow :-25.1 μ C/g, magenta :-24.3 μ C/g, cyan :-27.7 μ C/g, black :-23.0 μ C/g.

Developer installs in the identical imaging device, except that the gap A that changes between development sleeve 1 and magnetic scraper is the 800 μ m, develops under the development conditions identical with embodiment 1.Its result is similar to embodiment 1, and the image table of gained reveals the repeatability of good point and fine rule and high resolution, and carrier does not adhere to.The result of full color imaging shows on 30,000 paper continuously, and image is very similar to the quality of imaging for the first time.In continuous imaging, do not observe carrier and adhere to, the same good when the surface of carrier is with the first time behind the continuous imaging.

Embodiment 4

6.5 parts of phenol

3.5 parts of formalin (with embodiment 1)

81 parts of magnetic iron ore (with embodiment 1)

Al ₂O ₃(with embodiment 1) 9 parts

(dav＝0.63μm，Rs＝5×10 ¹³ohm.cm)

Make the above-mentioned material polymerization with the mode that is similar to embodiment 1.With the gradation after the polymerization, obtain to be dispersed with the resin carrier core of Magnaglo.The Rs of the carrier core of gained is 4.2 * 10 ¹¹Ohm.cm.

The slug particle application of resin coating identical with embodiment 1, but coating rate difference is 2.0wt.%.

The D of coating magnetic carrier particle ₁=24 μ m, sphericity (SF1) is 1.09.

Rs=7.2 * 10 of coating carrier granular ¹³Ohm.cm, σ _s=73emu/g.

Prepare toner in order to following component on the other hand.

Cyan toner

100 parts in vibrin (with embodiment 1)

6 parts of copper-phthalocyanine colors

5 parts of two-tert-butyl salicylic acid Cr-complex salts

Except that changing pulverizing and classification condition, with the mode of embodiment 1 prepare can be electronegative cyan powder (cyan toner), in the Henschel mixer with the mutual blending of titanium oxide fine powder of the hydrophobization of 100 parts cyan toner and 1.5wt. part, obtain having the outside cyan toner that adds titanium oxide fine powder, the D of cyan toner ₄=5.1 μ m, D ₁=4.0 μ m, D ₄/ D ₁=1.27, when measuring with the coating magnetic carrier for preparing above, its triboelectric charge (TC) is-46.2 μ C/g.

Cyan toner and coating magnetic carrier blending, toner concentration is 8wt.%, under the development conditions identical with embodiment 1, carries out single color mode imaging in same developing apparatus.The result is for the first time and press embodiment 1 and obtaining preferable image behind the continuous imaging on 30,000 paper.Carrier surface state similar with for the first time time the behind the continuous imaging.

Embodiment 5

The magnetic carrier of embodiment 1 preparation is as uncoated magnetic carrier, and with embodiment 1 in four kinds of developers of four kinds of toner blending preparations of preparation, the toner concentration of each is 8wt%.It is yellow that the triboelectric charge of four kinds of toners is respectively :-38.4 μ C/g, magenta :-35.7 μ C/g, cyan :-39.4 μ C/g, black :-36.6 μ C/g.

Four kinds of developers are put into same imaging device, under the development conditions identical, develop with embodiment 1, its result is similar to embodiment 1, imaging for the first time has high resolution, there is not carrier to adhere to, behind continuous imaging on 30,000 paper, image all has the quality of the similar imaging first time, does not have carrier to adhere in the continuous imaging.

Embodiment 6

6.5 parts of phenol

3.5 parts of formalin (with embodiment 1)

54 parts of magnetic iron ore (with embodiment 1)

TiO ₂36 parts

(d _av＝0.24μm，Rs＝3×10 ⁴ohm.cm)

Above-mentioned material carries out polymerization by similar embodiment 1, and the aggregated particles classification forms the Magnaglo resin carrier core that disperses.Rs=2.8 * 10 of gained carrier core ¹³Ohm.cm.

Be similar to embodiment 1,, obtain the coating rate of 1.2wt% with the multipolymer coating slug particle of styrene/methacrylic acid (2-ethylhexyl) ester (50/50).

The magnetic carrier particle D of coating ₁=45 μ m, sphericity (SF1) is 1.05.

Coating carrier granular Rs=9.8 * 10 ¹³Ohm.cm, σ s=48emu/cm ³

So coating magnetic carrier that obtains and cyan toner blending of embodiment 1 gets developer, and the triboelectric charge of toner is-27.2 μ C/g.

Developer is packed in the identical imaging device, and carrying out single color mode under as the development conditions of embodiment 1 develops.All be similar to the picture quality that embodiment obtains in the imaging first time with behind continuous imaging on 30,000 paper.Prevent that the performance that carrier adheres to is all fine before and after the continuous imaging.Equally good after the imaging for the first time of carrier surface behind the continuous imaging.

Comparing embodiment 1

Weighing Fe ₂O ₃, CuO and ZnO, obtain composition, its content is respectively 50mol%, 27mol%, 23mol% is mixed together with bowl mill again, and potpourri is pulverized at 1000 ℃ of following sintering and with bowl mill, 100 parts of gained powder, 0.5 part of sodium polymethacrylate and water are mixed together in wet ball mill, form slurries.Make slurries form particle with spray drying.Then, particle obtains the carrier slug particle at 1200 ℃ of following sintering, Rs=4.0 * 10 ⁸Ohm.cm.

The carrier surface mode application of resin identical with embodiment 1.Gained carrier granular D ₁=47 μ m, Rs=1.1 * 10 ¹⁰Ohm.cm, sphericity (SF1)=1.24, σ _s=62emu/g.

The cyan toner blending of preparation obtains developer among gained carrier and the embodiment 1.The triboelectric charge of cyan toner is-26.9 μ C/g.

Developer is packed in the same imaging device, carries out monochromatic mode and develop under the condition that is similar to embodiment 1.Consequently the gained image has high solid section image color, but its point is more coarse, and the medium tone repeatability is poor.Do not find image fault at image section and non-image part, but, find the toner image blooming because carrier adheres to.And the fusing that can be observed toner behind the continuous imaging that is similar to embodiment 1 on carrier bonds.The image that forms behind continuous imaging also is accompanied by the chap of further half tint and further image blurring.

Comparing embodiment 2

10 parts of phenol

6 parts of formalin (with embodiment 1)

31 parts of magnetic iron ore

(d _av＝0.61μm，Rs＝5×10 ⁵ohm.cm)

α-Fe ₂O ₃53 parts

(d _av＝0.6μm，Rs＝8×10 ⁹ohm.cm)

Except that the consumption that changes base catalyst and water, with the mode polymerization of above-mentioned material by similar embodiment 1.The classification of gained aggregated particles obtains being dispersed with the resin carrier core of magnetic material, Rs=5.9 * 10 of gained carrier core ⁸Ohm.cm.

Slug particle is pressed embodiment 1 coating.

The D of gained magnetic carrier particle ₁=45 μ m, sphericity (SF1) is 1.07.

The Rs=1.0 of gained carrier granular * 10 ¹¹Ohm.cm, σ _s=29emu/g.

The cyan toner blending for preparing among the magnetic carrier of the coating that so obtains and the embodiment obtains developer.The triboelectric charge of this cyan toner is-28.8 μ C/g.

Developer is put into same imaging device, develops being similar under the development conditions of embodiment.On primary medium tone image, just be attended by chap, and can see that carrier adheres to.

Comparing embodiment 3

6.5 parts of phenol

3.5 parts of formalin (with embodiment 1)

45 parts of magnetic iron ore (with embodiment 1)

α-Fe ₂O ₃45 parts

(d _av＝0.61μm，Rs＝5×10 ⁵ohm.cm)

Press embodiment 1 from above-mentioned material and obtain aggregated particles, and classification obtains being dispersed with the resin carrier core of magnetic material.The Rs=7.5 of gained carrier * 10 ⁷Ohm.cm.

Slug particle is pressed embodiment 1 coating.

The magnetic carrier particle D of coating ₁=45 μ m, sphericity (SF1)=1.06.

Carrier granular Rs=2.2 * 10 of coating ¹⁰Ohm, σ _s=73emu/g.

So the cyan toner blending of preparation prepares developer among coating magnetic carrier that obtains and the embodiment 1.The triboelectric charge of cyan toner is-30.8 μ C/g.

Developer is put into same imaging device, develops under the development conditions of embodiment 3.Prevent that the performance that carrier adheres to is good, but the middle tone color image is with the distortion of a shape, and can sees chap.

Comparing embodiment 4

Carrier is the coating carrier identical with embodiment 1, make cyan toner with mode identical among the embodiment 1 and composition, but its pulverizing is different with the classification condition.

Be similar to embodiment 1, toner is mixed with the titanium dioxide of the outside interpolation of 0.5wt%.Gained cyan toner D ₄=12.6 μ m, D ₁=8.3 μ m, D ₄/ D ₁=1.52.When the magnetic carrier with above-mentioned preparation with the toner concentration be 5wt% when measuring triboelectric charge be-20.1 μ C/g.Cyan toner and the blending of above-mentioned coating magnetic carrier prepare developer.

Developer is put into same imaging device, develops under the development conditions identical with embodiment 1.The result obtains high image density, but the middle tone color image shows relatively poor some repeatability and with chap.

Embodiment 7

The carrier core of preparation among 100 parts of embodiment 1 and contains 2 parts of thermosetting phenolic resins and 6 parts of α-Fe ₂O ₃(with embodiment 1) concentration is that 10% the coating liquid in toluene mixes, and evaporating solvent applies under the shearing force utilizing.These external 160 ℃, at the magnetic carrier particle that utilizes resin solidification formation coating under the situation of shearing force.The carrier granular of coating is separated and is reunited and classification.Gained coating magnetic carrier D ₁=45 μ m, SF1=1.06, Rs=1.0 * 10 ¹³Ohm.cm, Armco magnetic iron compound/nonmagnetic metal oxide have ratio pb1/pa1=0, a pb2/pa2=27.6.

So four colour toners blending of preparation prepare the developer of four kinds of two-component-types among the coating magnetic carrier that obtains and the embodiment 1, and the toner concentration in every kind is 8.0wt%.It is yellow that the triboelectric charge of toner is respectively :-25.5 μ C/g, magenta :-25.1 μ C/g, cyan :-25.9 μ C/g, black-24.3 μ C/g.

Developer is put into same imaging device, develops under identical development conditions.The image of good medium tone repeatability and high image color have been obtained to have.Particularly the triboelectric charge of toner is stable in continuous imaging.

Embodiment 8

In similar mode among the embodiment 1, use with embodiment 1 in identical silicone resin further apply the coating magnetic carrier of preparation among the embodiment 7.Gained coating magnetic carrier D ₁=45 μ m, SF1=1.05, Rs=9.8 * 10 ¹³Ohm.cm, Armco magnetic iron compound/nonmagnetic metal oxide have a ratio pb1/pa1=0.pb2/pa2=29.3.

So four colour toners blending of preparation among coating magnetic carrier that obtains and the embodiment 1 prepare four kinds of two-component developers.Its toner concentration is 8.0wt%, and it is yellow that its triboelectric charge is respectively :-23.0 μ C/g, magenta :-22.5 μ C/g, cyan :-24.4 μ C/g, black :-23.2 μ C/g.

Developer is put into same imaging device, develops under identical development conditions.The image and the high image density of good middle tone color reproduction have been obtained to have.Developer shows the Vback scope that wide especially image blur prevention and carrier adhere to, and advantages of excellent stability.

Embodiment 9

Obtain the magnetic carrier core with following material by two-stage polymerization:

The first step

7.5 parts of phenol

4.5 parts of formalin (with embodiment 1)

70 parts of magnetic iron ore (with embodiment 1)

Second step

2.5 parts of phenol

1.5 parts of formalin (with embodiment 1)

5 parts of magnetic iron ore (with embodiment 1)

α-Fe ₂O ₃(with embodiment 1) 9 parts

Similar embodiment 3 obtains slug particle, Rs=3.3 * 10 ¹²Ohm.cm, Armco magnetic iron compound/nonmagnetic metal oxide have ratio pb1/pa1=0, a pb2/pa2=4.58.

Slug particle is pressed embodiment 1 coating.

Coating magnetic carrier particle D ₁=40 μ m, sphericity (SF1) is 1.10.

Coating carrier granular Rs=3.2 * 10 ¹³Ohm.cm, σ _s=67emu/g.

So toner blending of four kinds of colors of preparation among coating magnetic carrier that obtains and the embodiment 1 prepares four kinds of two-component developers, and its toner concentration is 8%.It is yellow that the triboelectric charge of toner is respectively :-25.6 μ C/g, magenta :-25.0 μ C/g, cyan :-26.2 μ C/g, black :-24.9 μ C/g.

Developer is put into same imaging device, develops under the development conditions identical with embodiment 1.Its result is similar to embodiment 1, has obtained to have the image and the high image density of good medium tone repeatability.And do not have do not have the image blurring of toner because carrier adheres to the distortion that causes in image section and non-image part yet.As the result of 30,000 continuous full color imagings, the gained image does not have the scattering of toner, has high solid section image color, the repeatability of the Neutral colour harmonic line (of a cubic) picture of becoming reconciled.Not observing carrier in continuous imaging adheres to.Observe blue developer with SEM behind the continuous imaging, do not observe peeling off of overlay, the carrier of surface state with for the first time the time is the same good.

Embodiment 10

The aggregated particles of preparation further applies with the polymerization of following component among the embodiment 9.

2 parts of phenol

1.2 parts of formalin (with embodiment 1)

α-Fe ₂O ₃(with embodiment 1) 10 parts

With with embodiment 3 in identical mode carry out suspension polymerization and obtain the ball type carrier core.Gained carrier core magnetic=9.3 * 10 ¹²It is pb1/pa1=0 that there are ratio in ohm.cm, Armco magnetic iron compound/nonmagnetic metal oxide, pb2/pa2=32.3.

Slug particle applies with the application of resin of embodiment 2, but coating rate difference is 1.0wt%.

The magnetic carrier particle D of coating ₁=42 μ m, sphericity (SF1) is 1.11.

Carrier granular Rs=1.1 * 10 of coating ¹⁴Ohm.cm, σ _s=60emu/g.

So toner blending of four kinds of colors of preparation among coating magnetic carrier that obtains and the embodiment 1 prepares four kinds of two-component developers, and its toner concentration is 8wt%.It is yellow that the triboelectric charge of toner is respectively :-32 μ C/g, magenta :-29.9 μ C/g, cyan :-32.4 μ C/g, black :-30.3 μ C/g.

Developer is put into same image equipment, develops under the development conditions identical with embodiment 1.Similar to embodiment 1, once obtain repeatability and high resolving power that image demonstrates good especially point and fine rule.Do not find the toner scattering simultaneously, image blurring or carrier adheres to.As the result of continuous full color imaging on 30,000 paper, the imaging quality very similar first time of imaging afterwards.Do not find the toner scattering in continuous imaging, image blurring or carrier adheres to.It is the same good when carrier surface is with imaging for the first time behind the continuous imaging.

The above mentioned characteristic properties of carrier is summarised in the table 1, and assessment result is summarised in the table 2, after evaluation criteria is listed in table 2.

Table 1

	Core							Carrier
												The Armco magnetic iron compound		The nonmagnetic metal oxide		????r a/r b	Bonding * dosage (wt.%)	????Rs ?(ohm.cm)	????Rs ?(ohm.cm)	????σ s??(emu/g)	????D1 ??(μm)	???d B **???(g/cm 3)
	????r a(D 1) ????(μm)	Amount (wt.%)	????r b(D 1) ????(μm)	Amount (wt.%)
					Embodiment 123456 relatively implements 1 example, 23 embodiment 789 10	0.24 " 0.24 " 0.24 " 0.24 " 0.24, magnetic iron ore 0.24 " 0.24 " 0.24 " 0.24 " 0.24 " 0.24 CuZn ferrite magnetic iron ore 0.61 "	????31 ????44 ????75 ????81 ????31 ????54 ???100 ????31 ????45 ????31 ????31 ????75 ??66.2	a-Fe 2O 3" 0.6 0.4 " 0.6 aluminium oxide 0.63 α-Fe 2O 3???0.6 TiO 2????????0.7 ????????- α-Fe 2O 30.4 magnetic iron ore 0.61 α-Fe 2O 3???0.6 ????″????????0.6 ????″????????0.6 ????″????????0.6	????53 ????44 ????9 ????9 ????53 ????36 ????- ????53 ????45 ????53 ????53 ????9 ???16.8	????2.5 ????1.7 ????2.5 ????2.6 ????2.5 ????2.9 ????- ???0.66 ????2.5 ????2.5 ????2.5 ????2.5 ????2.5	????16 ????16 ????16 ????10 ????16 ????10 ????- ????16 ????10 ????16 ????16 ????16 ????17	8.0×10 125.2×10 127.4×10 124.2×10 118.0×10 122.8×10 134.0×10 85.9×10 87.5×10 88.0×10 128.0×10 123.3×10 129.3×10 12	9.0×10 138.0×10 133.5×10 137.2×10 138.0×10 129.8×10 131.1×10 101.0×10 112.2×10 101.0×10 139.8×10 133.2×10 131.1×10 14	????28 ????39 ????68 ????71 ????28 ????48 ????62 ????29 ????73 ????26 ????25 ????67 ????60	????43 ????55 ????40 ????24 ????43 ????45 ????47 ????45 ????45 ????45 ????45 ????40 ????42								????1.85 ????1.88 ????1.86 ????1.9 ????1.85 ????1.91 ????2.35 ????1.85 ????1.84 ????1.89 ????1.87 ????1.87 ????1.92

*. except that special declaration, cementing agent is a phenolics.* .d _BThe expression bulk density.

Table 2

Embodiment or comparing embodiment	Clearance C (mm)	Solid cyan I.D.	The medium tone chap	Carrier adheres to	Image blurring
						Embodiment 123456 comparing embodiments 1234 embodiment 789 10	?????5 ?????5 ????6.5 ?????6 ?????5 ????5.5 ????6.5 ?????5 ????5.5 ?????5 ?????5 ?????5 ????6.5 ????6.5	?????1.63 ?????1.61 ?????1.69 ?????1.68 ?????1.59 ?????1.62 ?????1.58 ?????1.55 ?????1.6 ?????1.71 ?????1.61 ?????1.65 ?????1.65 ?????1.66	◎ ◎ ◎ ◎ ○ ◎ x Δx Δx Δx ◎ ◎ ◎ 6	○ ○ ◎ ○ ○ ○ ○ x????? ○ ○ ○ ○ ◎ ◎	◎ ◎ ○ ◎ ○ ◎ x ○ Δ ○ ○ ◎ ○ ◎

◎: excellent, zero: good, Δ: in, Δ x: poor slightly, x: poor

(notes of his-and-hers watches 2) solid cyan I.D is the relative concentration that is imprinted on an image on the common paper with the solid cyan image image color partly that Macbeth densimeter (use " RD-918 type " of SPI filtrator, produced by Macbeth company) records.The medium tone chap

With reference to original image and standard model, estimate the chap degree of medium tone image section with eyes.

Carrier adheres to

After forming the solid white image, transparent adhesive tape is put into the zone of the developing regional and the 5cm * 5cm between the cleaning area of photosensitive drum, recovery is attached to the magnetic carrier particle on the photosensitive drum, number go out attached to 5cm * 5cm zone adhere to the carrier granular number, based on the every cm that calculates ²On adhere to carrier the grain number, again according to following criterion evaluation:

◎ (excellent): less than 10/cm ²

Zero (very): 10-less than 20/cm ²

Δ (in): 20-less than 50/cm ²

Δ X:(is poor slightly) 50-less than 100/cm ²

X (poor): 100/cm ²Or it is more

Image blurring rate

Before printing, measure the average reflectance Dr (%) of common paper with reflectometer (" REFLECTOMETER MODEL TC-6DS " made by Tokyo Denshoku k.k).On the other hand, the solid white image is printed on the common paper, measure the reflectivity Ds (%) of solid white image with reflectometer, image blurring rate (%) is calculated by following equation: image blurring rate (%)=Dr (%)-Ds (%) is according to following criterion evaluation ◎ (excellent): be lower than 1.0% 0 (very): 1.0-be lower than 1.5% Δ (in): 1.5-to be lower than 2.0% Δ X:(poor slightly) 2.0-be lower than 3.0%X (poor): 3.0% or higher.

Claims (40)

1. be used to show the two-component-type developer of electrostatic image, comprise at least a toner and a kind of magnetic carrier; Wherein

The weight average particle diameter D of toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5;

Magnetic carrier comprises the composite particles that contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contain the cementing agent of phenolics, and the Armco magnetic iron compound particle that composite particles is contained and the toatl proportion of nonmagnetic metal oxide particle are 80-99wt%; The number average bead diameter of Armco magnetic iron compound is γ a, and the number average bead diameter of nonmagnetic metal oxide particle is γ b, satisfies γ _b/ γ _a＞1.0.

2. according to the developer of claim 1, the number average bead diameter γ of Armco magnetic iron compound particle wherein _aBe 0.02-5 μ m, the number average bead diameter γ of nonmagnetic metal oxide particle _bBe 0.05-10 μ m.

3. according to the developer of claim 1 or 2, the amount of wherein contained nonmagnetic metal oxide particle accounts for 5-70wt% of Armco magnetic iron compound particle and nonmagnetic metal oxide particle total amount, and the bulk density of magnetic carrier is 1.0-2.0g/cm ³

4. according to the developer of claim 1, wherein the magnetic carrier surface applies with the resin that contains the nonmagnetic metal oxide particle.

5. according to the developer of claim 1 or 4, wherein the magnetic carrier surface applies with the resin of 0.1-10wt%.

6. according to the developer of claim 1, the saturation magnetization σ of magnetic carrier wherein _sBe 10-80emu/g.

7. according to the developer of claim 1, wherein the Armco magnetic iron compound comprises magnetic iron ore, but not magnetic metal oxide comprises haematite.

8. according to the developer of claim 1, wherein toner is a nonmagnetic toner.

9. according to the developer of claim 1, wherein the Armco magnetic iron compound particle that contains of magnetic carrier and nonmagnetic metal oxide particle are to distribute like this: the cumulative volume that appears at the Armco magnetic iron compound particle of inside, carrier (core) particle cross section is pa1, the cumulative volume of nonmagnetic metal oxide particle is pb1, the cumulative volume of Armco magnetic iron compound particle that appears at the surface portion in carrier (core) particle cross section is pa2, the cumulative volume of nonmagnetic metal oxide particle is pb2, they satisfy pb1/pa1＜1, and pb2/pa2＞1, so that higher resistivity to be provided.

10. according to the developer of claim 1, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.5-10wt%.

11. according to the developer of claim 10, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.6-5wt%.

12. according to the developer of claim 1, wherein the sphericity of magnetic carrier is 2 to the maximum.

13. the developing method of a developing electrostatic image comprises:

With the developer of a kind of two component-types of developer carrier band component carrier tape that field generator for magnetic is arranged, described two-component developer comprises a kind of toner and a kind of magnetic carrier; Wherein,

The weight average particle diameter D of toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5;

Magnetic carrier comprises the composite particles that contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contain the cementing agent of phenolics; The Armco magnetic iron compound particle that composite particles is contained and the toatl proportion of nonmagnetic metal oxide particle are 80-99wt%; The number average bead diameter of Armco magnetic iron compound particle is γ _a, the number average bead diameter of nonmagnetic metal oxide particle is γ _bSatisfy γ _b/ γ _a＞1.0.

On developer carrier band element, form the magnetic brush of two-component developer;

Magnetic brush is contacted with the sub-image load-carrying unit; And

The electrostatic image that develops on the sub-image load-carrying unit forms toner image, applies an alternating electric field to developer carrier band element simultaneously.

14. according to the developing method of claim 13, wherein electrostatic image comprises digital picture.

15. according to the developing method of claim 13 or 14, wherein electrostatic image develops by the discharged-area development pattern.

16. according to the developing method of claim 13, the number average bead diameter γ of Armco magnetic iron compound particle wherein _aBe 0.02-5 μ m, the number average bead diameter γ of nonmagnetic metal oxide particle _bBe 0.05-10 μ m.

17. according to the developing method of claim 13 or 16, wherein the amount of nonmagnetic metal oxide particle accounts for 5-70wt% of Armco magnetic iron compound particle and nonmagnetic metal oxide particle total amount, the bulk density of magnetic carrier is 1.0-2.0g/cm ³

18. according to the developing method of claim 13, wherein the magnetic carrier surface applies with the resin that contains the nonmagnetic metal oxide particle.

19. according to the developing method of claim 13, wherein the magnetic carrier surface applies with the resin of 0.1-10wt%.

20. according to the developing method of claim 13, the saturation magnetization σ of magnetic carrier wherein ₃Be 10-80emu/g.

21. according to the developing method of claim 13, wherein the Armco magnetic iron compound comprises magnetic iron ore, but not magnetic metal oxide comprises haematite.

22. according to the developing method of claim 13, wherein toner is a nonmagnetic toner.

23. developing method according to claim 13, wherein contained Armco magnetic iron compound particle of magnetic carrier and nonmagnetic metal oxide particle are to distribute like this, the cumulative volume that appears at the Armco magnetic iron compound particle of inside, carrier (core) particle cross section is pa1, the cumulative volume of nonmagnetic metal oxide particle is pb1, the cumulative volume that appears at the Armco magnetic iron compound particle of carrier (core) particle cross-sections surfaces part is pa2, the cumulative volume of nonmagnetic metal oxide particle is pb2, they satisfy pb1/pa1＜1, and pb2/pa2＞1, so that higher resistivity to be provided.

24. according to the developing method of claim 13, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.5-1.0wt%.

25. according to the developing method of claim 24, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.6-5wt%.

26. according to the developing method of claim 13, wherein the sphericity of magnetic carrier is 2 to the maximum.

27. a formation method comprises: (I) be encapsulated in the developer of a kind of two-component-type of developer carrier band component carrier tape wherein with field generator for magnetic, the developer of described two-component-type comprises magenta toner and magnetic carrier; Wherein

The weight average particle diameter D of magenta toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5;

Magnetic carrier comprises the composite particles that contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contain the cementing agent of phenolics; The Armco magnetic iron compound that composite particles is contained and the toatl proportion of nonmagnetic metal oxide are 80-99wt%; The number average bead diameter of Armco magnetic iron compound is γ _a, the number average bead diameter of nonmagnetic metal oxide particle is γ _b, satisfy γ _b/ γ _a＞1.0,

On developer carrier band element, form the magnetic brush of two-component developer,

Magnetic brush is contacted with the sub-image load-carrying unit;

The electrostatic image that develops on the sub-image load-carrying unit forms the magenta toner image, applies an alternating electric field to developer carrier band element simultaneously; (II) be encapsulated in wherein a kind of two-component developer of developer carrier band component carrier tape with field generator for magnetic, described two-component developer contains cyan toner and a kind of magnetic carrier; Wherein

The weight average particle diameter D of green lake toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5;

Magnetic carrier comprises particle, nonmagnetic metal oxide particle that contains the Armco magnetic iron compound and the composite particles that contains the cementing agent of phenolics, and the Armco magnetic iron compound particle that composite particles is contained and the toatl proportion of nonmagnetic metal oxide particle are 80-99wt%; The number average bead diameter of Armco magnetic iron compound particle is γ a, and the number average bead diameter of nonmagnetic metal oxide particle is γ _b, satisfy γ _b/ γ a＞1.0,

On the developer carrier element, form the magnetic brush of two-component developer,

Magnetic brush is contacted with the sub-image load-carrying unit;

The electrostatic image that develops on the sub-image load-carrying unit forms the cyan toner image, applies an alternating electric field to developer carrier band element simultaneously; (III) be encapsulated in wherein a kind of two-component developer of developer carrier band component carrier tape with field generator for magnetic, described two-component developer contains Yellow toner and a kind of magnetic carrier; Wherein

The weight average particle diameter D of Yellow toner ₄Be 10 μ m to the maximum, number average bead diameter D ₁Satisfy D ₄/ D ₁≤ 1.5;

Magnetic carrier comprises the composite particles that contains Armco magnetic iron compound particle, nonmagnetic metal oxide particle and contain the cementing agent of phenolics; Contained Armco magnetic iron compound of composite particles and nonmagnetic metal oxide toatl proportion are 80-99wt%; The number average bead diameter of Armco magnetic iron compound particle is γ _a, the number average bead diameter of nonmagnetic metal oxide particle is γ _b, satisfy γ _b/ γ _a＞1.0,

On developer carrier band element, form the magnetic brush of two-component developer,

Magnetic brush is contacted with the sub-image load-carrying unit,

The electrostatic image that develops on the sub-image load-carrying unit forms the yellow tone image, applies an alternating electric field to developer carrier band element simultaneously; (IV) at least with the magenta toner image that forms above, cyan toner image and yellow toner image form full-colour image.

28. according to the formation method of claim 27, wherein electrostatic image comprises digital picture.

29. according to the formation method of claim 27 or 28, wherein electrostatic image develops by the discharged-area development pattern.

30. according to the formation method of claim 27, the number average bead diameter γ of Armco magnetic iron compound particle wherein _aBe 0.02-5 μ m, the number average bead diameter γ of nonmagnetic metal oxide particle _bBe 0.05-10 μ m.

31. according to the formation method of claim 27, wherein the amount of nonmagnetic metal oxide particle accounts for 5-70wt% of Armco magnetic iron compound particle and nonmagnetic metal oxide particle total amount, the bulk density of magnetic carrier is 1.0-2.0g/cm ³

32. according to the formation method of claim 27, wherein the magnetic carrier surface applies with the resin that contains the nonmagnetic metal oxide particle.

33. according to the formation method of claim 27, wherein the magnetic carrier surface applies with the resin of 0.1-10wt%.

34. according to the formation method of claim 27, wherein the saturation magnetization σ s of magnetic carrier is 10 1 80emu/g.

35. according to the formation method of claim 27, wherein the Armco magnetic iron compound comprises magnetic iron ore, but not magnetic metal oxide comprises haematite.

36. according to the formation method of claim 27, wherein toner is a nonmagnetic toner.

37. formation method according to claim 27, wherein contained Armco magnetic iron compound particle of magnetic magnet and nonmagnetic metal oxide are to distribute like this, the cumulative volume that appears at the Armco magnetic iron compound particle of inside, carrier (core) particle cross section is pa1, the cumulative volume of nonmagnetic metal oxide particle is pb1, appearing at the cumulative volume that carrier (core) particle cuts the Armco magnetic iron compound particle of surperficial surface portion is pa2, the cumulative volume of nonmagnetic metal oxide particle is pb2, they satisfy pb1/pa1＜1, and pb2/pa2＞1, so that higher resistivity to be provided.

38. according to the formation method of claim 27, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.5-10wt%.

39. according to the formation method of claim 38, wherein magnetic carrier comprises the carrier core of the coating material coating of a kind of usefulness 0.6-5wt%.

40. according to the formation method of claim 27, wherein the sphericity of magnetic carrier is 2 to the maximum.

Images