JP4753365B2 - Toner, image forming method and process cartridge - Google Patents

Description

  The present invention relates to an electrostatic charge developing toner composition for use in a copying machine, a printer, or the like to which electrophotographic technology is applied, and an image forming method using the same, and more specifically, presses a developing roller and a regulating blade to form a thin film. The present invention relates to a toner and an image forming method suitable for an image forming apparatus having a developing device for forming a layer.

Conventionally, in electrophotography, an electrostatic latent image formed by charging and exposing a photoreceptor surface is developed with a colored toner to form a toner image, and the toner image is transferred to a transfer medium such as transfer paper. This is fixed with a heat roll or the like to form an image.
Dry development methods employed in electrophotography, electrostatic recording, and the like include a method using a two-component developer composed of a toner and a carrier and a method using a one-component developer not containing a carrier. The former method provides a relatively stable and good image, but it is difficult to obtain a constant quality image over a long period of time because carrier deterioration and a change in the mixing ratio of toner and carrier are likely to occur. In addition, there are difficulties in maintaining and managing the apparatus and making it compact. In view of this, a method using the latter one-component developer which does not have such drawbacks has been attracting attention.

  By the way, in this system, means for visualizing the electrostatic latent image formed on the latent image carrier by the toner (developer) usually conveyed by at least one toner conveying member and the conveyed toner. In this case, the layer thickness of the toner transported on the surface of the toner transport member must be made as thin as possible. In particular, when a one-component developer is used and a toner having a high electrical resistance is used, the toner needs to be charged by a developing device, so that the toner layer thickness must be significantly reduced. This is because if the toner layer is thick, only the surface of the toner layer is charged, and the entire toner layer is difficult to be uniformly charged.

  In view of this demand, various methods have been proposed as means for regulating the toner layer thickness on the toner conveying member (toner layer thickness regulating means). As a typical example, a regulating blade is used, and this blade is used as the toner conveying member. Thus, the toner conveyed on the surface of the toner conveying member is pressed by a pressing member (regulating blade) to control the toner layer thickness. There is also a type that obtains the same effect by contacting a roller instead of a blade.

In the developing process, in the toner layer formed on the surface of the developing sleeve by the developer layer thickness regulating member, the toner present in the vicinity of the developing sleeve surface in the toner layer has a very high charge. Since the toner is strongly attracted to the surface of the sleeve by the reflection force and becomes immobile on the surface of the developing sleeve, the toner does not move from the developing sleeve to the latent image on the latent image carrier, and a charge-up phenomenon is likely to occur. Become. In particular, the charge-up phenomenon is likely to occur at low temperatures and low humidity.
When such a charge-up phenomenon occurs, the toner on the upper layer of the toner layer formed on the developing sleeve is less likely to be charged, so the charge amount of the toner is reduced. It tends to cause toner leakage and toner scattering.
In order to eliminate such a phenomenon, it is necessary to have a configuration in which the charge amount of the toner in the toner layer formed on the developing sleeve can be controlled as uniformly as possible.

In order to solve such problems, various treatment agents are used as described later, but problems arise.
Magnesium silicate minerals (attapulgite, sepiolite, etc.) described in Patent Document 1 have a high water content and are liable to cause poor charging even in a normal use environment. Problems are likely to occur.
When the magnesium silicate treated with the silicone oil described in Patent Documents 2 to 4 is used, the toner fluidity deteriorates due to the silicone oil, the charge rises, and the like, causing poor conveyance in the developing unit and density reduction. In addition, the magnesium silicate having a particle size described in the examples is likely to be detached in the developing device, and the developing member and the latent image carrier are likely to be contaminated. Particularly in a toner using an organic boron compound. Will severely deteriorate durability and adversely affect images.

In the toner described in Patent Document 5, when a silicate fine powder is made of magnesium silicate and a toner with a coverage of 60 to 100% is prepared, when it is used as a negatively charged toner, a reversely charged toner is likely to be generated and a background stain is likely to occur. This is because magnesium silicate tends to be positively charged due to the influence of the MgO portion, which tends to be strongly positively charged, as shown by the relationship of electronegativity (Non-patent Document 1).
When the titanic acid fine powder is used as in the toner described in Patent Document 6, since the material itself has a low resistance, charging leakage is large, and background contamination, toner leakage, and toner scattering are likely to occur.
Even when titania is used as in the toner described in Patent Document 7, it is difficult to adjust the amount of addition because this material is a low-resistance and high-dielectric constant material. In addition, when the amount is small, the charge is increased. As a result, in both cases, scumming, toner leakage, and toner scattering are likely to occur.
Patent Document 8 describes a toner for developing an electrostatic latent image in which inorganic particles each having at least an alkali metal salt of a fatty acid and a non-alkali metal salt of a fatty acid are externally added to the toner base particles. However, this toner is also not sufficiently satisfactory with respect to background contamination and toner leakage.

JP 2002-31913 A JP-A-3-294864 JP-A-4-214568 JP-A-5-165257 JP 11-95480 A JP-A-11-184239 JP 2003-186240 A Japanese Patent Laid-Open No. 2001-100453 Journal of the Imaging Society of Japan Vol.39 No.3 259

The present invention has been made for the purpose of solving the above problems in the prior art.
An object of the present invention relates to an electrostatic charge developing toner composition used for a copying machine, a printer, or the like applying electrophotographic technology, and an image forming method using the same, and more particularly, between a developing roller and a regulating blade in a developing device. By efficiently and uniformly performing tribocharging, ground contamination does not occur, and toner leakage of the supplied toner due to toner reset failure on the developing roller, streaks on the conveyance surface due to electrostatic aggregation, and charger contamination are suppressed. Furthermore, it is an object of the present invention to provide an electrostatic charge developing toner composition capable of obtaining excellent image stability and an image forming method using the toner composition.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by treating the toner with specific inorganic fine particles, and have completed the present invention.
That is, this invention is the following (1)-(6).

(1) A toner obtained by externally adding inorganic fine particles to a toner base having at least a binder resin and a colorant, wherein the inorganic fine particles are forsterite fine particles surface-treated with a fatty acid.
(2) The toner according to (1), wherein the fatty acid is a fatty acid represented by the following general formula (2).
C _n H _{2n + 1} COOH (2)
(N = 10-25)
(3) The forsterite fine particles have an average primary particle size of 0.05 μm to 0.15 μm and an average secondary particle size of 0.2 μm to 0.6 μm. The toner according to (1) or (2) above, to which 2 parts by mass is added.
( 4 ) In an image forming method for forming a color image with a toner obtained by externally adding inorganic fine particles to a toner base having at least a binder resin and a colorant, the image forming method includes at least an electrostatic latent image. An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image holding body having a primary charge and a plurality of developing devices having the electrostatic latent image; Development with a one-component development method in which a toner image of each color is developed and formed on the electrostatic latent image holding member, and the toner image of each color formed on the latent image holding member is transferred to a recording material A transfer step and a fixing step of fixing the toner image transferred to the recording material to the recording material, wherein the toner is the toner described in any one of (1) to ( 3 ) above. A non-magnetic one-component image forming method.
( 5 ) In a process cartridge that integrally supports an electrostatic latent image holding member and at least one unit selected from a charging unit, a developing unit, and a cleaning unit and is detachable from the main body of the image forming apparatus, the developing unit includes: A process cartridge which holds toner and is the toner according to any one of (1) to ( 3 ).

  By using the toner of the present invention, background contamination does not occur, and toner leakage of supply toner due to toner reset failure on the developing roller, conveyance surface streaks due to electrostatic aggregation, and charger contamination are suppressed. And excellent image stability can be obtained.

The toner of the present invention is a toner obtained by externally adding inorganic fine particles to a toner base having at least a colorant and a resin, and at least one of the inorganic fine particles is represented by the following general formula (1) Mg _x Si _y O _{(x + 2y)} (1), which is a toner that is a compound and has a surface treated with a fatty acid.
(However, x and y are integers.)
In particular, forsterite (Mg ₂ SiO ₄ ), steatite, and enstatite (MgSiO ₃ ) are preferable, and forsterite is particularly preferable because the effect of the present invention can be further exhibited.

The magnesium silicate compound is used as an external additive for the purpose of assisting charging of toner particles. The magnesium silicate compound preferably has a relative dielectric constant of 2 to 10 measured at 1 MHz, more preferably 3 to 9, and a volume resistivity of 10 ¹¹ Ω · cm or more, preferably 10 ¹² Ω · cm or more.
If the relative dielectric constant is less than 2, it does not function as a charging aid, and if it is more than 10, it causes a charge-up, and the toner in the developing device becomes non-uniformly charged. On the other hand, if the volume specific resistance is smaller than 10 ¹¹ Ω · cm, the surface resistance is lowered when the electrostatic latent image holding member is attached to a charging member for charging the electrostatic latent image holding member, thereby causing a charging failure of the electrostatic latent image holding member.

The preferable range of the average primary particle size of the magnesium silicate compound is 0.05 μm to 0.15 μm, more preferably 0.05 μm to 0.12 μm, still more preferably 0.06 μm to 0.12 μm, and the average secondary particle A preferable range of the diameter is 0.2 μm to 0.6 μm, more preferably 0.2 μm to 0.5 μm, and still more preferably 0.2 μm to 0.4 μm.
If the average secondary particle size of the magnesium silicate compound is larger than 0.6 μm, the adhesive force to the toner is weak and the toner is easily detached from the toner, so the toner carrier, the regulating member, and the latent image carrier are transferred. Causes component contamination. On the other hand, those having an average primary particle size of less than 0.05 μm are more likely to be embedded in the toner base due to friction between toners in the developing device or friction between the toner carrier and the regulating member. Or the toner base surface becomes non-uniformly charged, and the toner charge amount distribution spreads and low-charged toner is generated, causing streaks on the conveyance surface due to electrostatic aggregation and resetting the toner on the developing roller. The toner leakage of the supplied toner due to the defect is promoted.

The amount of the magnesium silicate compound to be mixed in the toner is 0.1 to 5.0 parts by weight, preferably 0.2 to 3.0 parts by weight, and more preferably 0.8 to 100 parts by weight of the toner base. 2 to 2.5 parts by mass. When the amount is less than 0.1 parts by mass, the effect of the present invention is not exhibited. When the amount exceeds 5.0 parts by mass, the toner chargeability is remarkably reduced, and toner spillage, excessive toner conveyance, toner scattering in the apparatus, and toner leakage. Leads to outbreak.
As a manufacturing method of the magnesium silicate used for this invention, the method of Unexamined-Japanese-Patent No. 2003-327470 is mentioned, for example.

Magnesium silicate compounds such as forsterite and steatite represented by the general formula (1) have a very weak adhesion to metal for an unknown reason. For this reason, when the thin layer forming member in the developing device is a metal, the adhesion of the toner to the metal is suppressed. When a metal roller is used, the prevention of filming and the improvement of the toner reset property are promoted, and a metal blade is used. In the case, there is an effect of preventing filming. In the present invention, particularly good effects can be obtained by using forsterite.
Hereinafter, forsterite will be described as an example of the calcium silicate compound.

Because forsterite is a positive particle, it has a strong adsorption force to the non-image area of the negatively charged photoconductor, and easily passes through the cleaning blade. Further, since the charger is negative, the forsterite that has passed through will adhere to the charger.
For this reason, forsterite particles are surface-treated with fatty acid, so that the forsterite is negatively charged, the adsorptive power with the photosensitive member is suppressed, and it is easy to collect with a cleaning blade. Moreover, even if it slips through, it is harder to hit the charger because it is charged more negatively.

The fatty acid for surface-treating forsterite particles is preferably represented by the following general formula (2).
C _n H _{2n + 1} COOH (2)
(N = 10-25, preferably 15-20)
When n is smaller than 10, melting easily occurs and image noise due to aggregation or the like occurs. Moreover, when larger than 25, it will be hard to melt | dissolve in water and it will become difficult to surface-treat. More preferably, n = 15-20.

Such fatty acids are not particularly limited, and examples thereof include lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, and arachidic acid. Preferably, lauric acid, myristic acid, palmitic acid, stearic acid, and arachidic acid are used, and more preferably lauric acid, palmitic acid, and stearic acid are used.
When inorganic fine particles having the fatty acid as described above at a specific ratio are used as an external additive, the chargeability is improved and charger contamination is suppressed.

The amount of the fatty acid surface-treated on the inorganic fine particles is 0.5 to 8.0 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the inorganic fine particles. When the amount is less than 0.5 parts by mass, the effect of the present invention is not exhibited, and when the amount exceeds 8.0 parts by mass, the photosensitive member filming is caused by free fatty acids that cannot be processed.
As a method for treating with fatty acid used in the present invention, as a method for treating with fatty acid used in the present invention, inorganic fine particles are dispersed in pure water, the aqueous slurry is made alkaline, and the fatty acid salt is added while heating, Examples thereof include a method in which fatty acids are precipitated using inorganic fine particles as nuclei.

The toner base that can be used in the present invention usually contains a binder resin, a colorant, and other additives. In this toner base, (1) a colorant, a charge control agent, a release agent and the like are melt-mixed and uniformly dispersed in a thermoplastic resin as a binder resin component to obtain a composition. A toner base obtained by pulverizing and classifying the product, and (2) a polymerization initiator in which a colorant, a charge control agent, a release agent and the like are dissolved or suspended in a polymerizable monomer which is a binder resin raw material. A toner base obtained by dispersing in an aqueous dispersion medium containing a dispersion stabilizer, heating to a predetermined temperature to start suspension polymerization, and filtering, washing, dehydrating and drying after completion of the polymerization, (3) The primary particles of the binder resin containing a polar group obtained by emulsion polymerization are aggregated by adding a colorant and a charge control agent to form secondary particles, and the temperature is higher than the glass transition temperature of the binder resin. The particles that were agitated and associated with the (4) Using a hydrophilic group-containing resin as a binder resin, adding a colorant or the like to the resin and dissolving it in an organic solvent, neutralizing the resin, phase-inverting, and then drying. Examples thereof include a phase inversion emulsification method toner base material for obtaining colored particles, and any of them can be used.
In the following, the present invention will be described using a pulverized toner as an example, but the present invention is not limited to this.

(Binder resin)
The type of binder resin is not particularly limited, and binder resins known in the field of full-color toners such as polyester resins, (meth) acrylic resins, styrene- (meth) acrylic copolymer resins, epoxy resins, COC (Cyclic olefin resin (for example, TOPAS-COC (manufactured by Ticona))) or the like, but from the viewpoint of stress resistance in the developing device, it is preferable to use a polyester resin.
As the polyester resin preferably used in the present invention, a polyester resin obtained by polycondensation of a polyhydric alcohol component and a polyvalent carboxylic acid component can be used.

  Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane Bisphenol A alkylene oxide adducts such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanedio , 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, and the like. Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Is mentioned.

  Among the polyvalent carboxylic acid components, examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. , Adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid , Isooctyl succinic acid, anhydrides or lower alkyl esters of these acids.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2 , 4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4- Examples include cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimer acid, anhydrides of these acids, and lower alkyl esters.

  In the present invention, as a polyester resin, a polyester resin raw material monomer, a vinyl resin raw material monomer, and a mixture of monomers that react with both resin raw material monomers are used to obtain a polyester resin in the same container. A resin obtained by performing a condensation polymerization reaction and a radical polymerization reaction for obtaining a vinyl resin in parallel (hereinafter, simply referred to as “vinyl polyester resin”) can also be suitably used. In addition, the monomer which reacts with the raw material monomers of both resins is, in other words, a monomer that can be used for both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxy group that can undergo a condensation polymerization reaction and a vinyl group that can undergo a radical polymerization reaction, and examples thereof include fumaric acid, maleic acid, acrylic acid, and methacrylic acid.

  Examples of the raw material monomer for the polyester resin include the aforementioned polyhydric alcohol component and polyvalent carboxylic acid component. Examples of the raw material monomer for the vinyl resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Styrene or styrene derivatives such as butylstyrene and p-chlorostyrene; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate , Isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 3- (methyl) butyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate Methacrylic acid alkyl esters such as decyl methacrylate, undecyl methacrylate, dodecyl methacrylate; methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, acrylic Alkyl acrylates such as n-pentyl acid, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, and dodecyl acrylate Esters; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid; acrylonitrile, maleic acid ester, itaconic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinylmethyl Examples include ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether. As a polymerization initiator when polymerizing the raw material monomer of the vinyl resin, for example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, benzoyl peroxide, dicumyl peroxide, And peroxide polymerization initiators such as methyl ethyl ketone peroxide, isopropyl peroxycarbonate, lauroyl peroxide, and the like.

As the binder resin, various polyester resins as described above are preferably used. Of these, from the viewpoint of further improving the separability and offset resistance as an oilless fixing toner, It is more effective and preferable to use two binder resins together.
That is, as the first binder resin, a polyester resin obtained by polycondensation of the above-described polyhydric alcohol component and polyvalent carboxylic acid component, in particular, a bisphenol A alkylene oxide adduct is used as the polyhydric alcohol component. A polyester resin obtained using terephthalic acid and fumaric acid as the acid component is used.
The second binder resin is a vinyl polyester resin, in particular, bisphenol A alkylene oxide adduct, terephthalic acid, trimellitic acid and succinic acid are used as raw material monomers for the polyester resin, and styrene and butyl acrylate are used as the raw material monomers for the vinyl resin. And a vinyl polyester resin obtained using fumaric acid as a bireactive monomer.

  In the present invention, it is preferable that a hydrocarbon wax is internally added during the synthesis of the first binder resin. In order to add the hydrocarbon wax to the first binder resin in advance, when the first binder resin is synthesized, the hydrocarbon wax is added to the monomer for synthesizing the first binder resin. What is necessary is just to synthesize | combine binder resin. For example, the polycondensation reaction may be performed in a state where a hydrocarbon wax is added to an acid monomer and an alcohol monomer constituting the polyester resin as the first binder resin. When the first binder resin is a vinyl-based polyester resin, the vinyl-based resin raw material monomer is added dropwise to the polyester resin raw-material monomer while stirring and heating the monomer while the hydrocarbon-based wax is added. The polycondensation reaction and the radical polymerization reaction may be performed.

(wax)
Generally, the lower the polarity of the wax, the better the releasability from the fixing member roller.
The wax used in the present invention is a hydrocarbon wax having a low polarity.
(Hydrocarbon wax)
The hydrocarbon wax is a wax composed of only carbon atoms and hydrogen atoms, and does not contain an ester group, an alcohol group, an amide group, or the like. Specific hydrocarbon waxes include polyolefin waxes such as polyethylene, polypropylene, copolymers of ethylene and propylene, petroleum waxes such as paraffin wax and microcrystalline wax, and synthetic waxes such as Fischer-Tropsch wax. . Among these, polyethylene wax, paraffin wax, and Fischer-Tropsch wax are preferable in the present invention, and polyethylene wax and paraffin wax are more preferable.

(Melting point of wax)
The melting point of the wax in the present invention is the peak top temperature of the endothermic peak of the wax at the time of temperature rise measured by a differential scanning calorimeter (DSC), and is preferably in the range of 70 ° C to 90 ° C. If it is higher than 90 ° C., the melting of the wax in the fixing process becomes insufficient, and the separation from the fixing member cannot be ensured. On the other hand, if the temperature is lower than 70 ° C., there is a problem in storage stability such that toner particles are fused in a high temperature and high humidity environment. In order to provide a sufficient margin for fixing separation at a low temperature, the melting point of the wax is more preferably from 70 ° C to 85 ° C, and further preferably from 70 ° C to 80 ° C.

(Endothermic peak of wax)
Moreover, it is preferable that the half value width of the wax endothermic peak at the time of temperature rise measured by a differential scanning calorimeter (DSC) is 7 ° C. or less. Since the melting point of the wax in the present invention is relatively low, a wax whose endothermic peak is broad, that is, melted from a low temperature range, adversely affects the storage stability of the toner.

(Wax content)
The wax content in the toner of the present invention is in the range of 3 to 10% by mass, preferably 4 to 8% by mass, and more preferably 4 to 6.5% by mass. If the wax content is less than 3% by mass, the amount of wax that exudes between the molten toner and the fixing member in the fixing process is insufficient, and the adhesive force between the molten toner and the fixing member does not decrease. The recording member does not leave the fixing member. On the other hand, if the wax content exceeds 10% by mass, the amount of wax exposed on the toner surface increases, and the transfer efficiency from the developing unit to the photoconductor and from the photoconductor to the recording member increases due to the deterioration of the fluidity of the toner particles. This is not preferable because not only the image quality is significantly lowered, but also the wax on the surface of the toner is detached to cause contamination of the developing member and the photosensitive member.

(Content ratio of first binder resin and second binder resin)
The content ratio of the first binder resin (including the weight of the internally added wax) and the second binder resin in the toner particles is 80/20 to 55/45, preferably 70/30 to 60/40 by weight. If the amount is too small, the separability and high-temperature offset resistance deteriorate, which causes a problem. When there is too much 1st binder resin, glossiness and heat-resistant storage property will fall.
More preferably, the softening point of the binder resin composed of the first binder resin and the second binder resin used in the above weight ratio is 100 to 125 ° C., particularly preferably 105 to 125 ° C. In the present invention, the softening point of the binder resin composed of the first binder resin and the second binder resin into which wax is internally added may be in the above range.

The acid value of the wax-added first binder resin is preferably 5 to 50 KOHmg / g, and more preferably 10 to 40 KOHmg / g. The acid value of the second binder resin is preferably 0 to 10 KOHmg / g, and more preferably 1 to 5 KOHmg / g. In particular, when a polyester resin is used, by using a resin having such an acid value, the dispersibility of various colorants and the like can be improved, and a toner having a sufficient charge amount can be obtained.
The first binder resin preferably contains a component insoluble in tetrahydrofuran (THF) from the viewpoint of high temperature offset resistance. The THF-insoluble component content in the first binder resin added with wax is preferably 0.1 to 15% by weight, particularly 0.2 to 10% by weight, and more preferably 0.3 to 5% by weight.

(Coloring agent)
As the colorant used in the present invention, known pigments and dyes conventionally used as colorants for full-color toners can be used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 184, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Solvent Yellow 162, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment blue 15: 1, C.I. I. And CI Pigment Blue 15: 3. The content of the colorant in the toner particles is preferably in the range of 2 to 15 parts by weight with respect to 100 parts by weight of the total binder tree. It is preferable from the viewpoint of dispersibility that the colorant is used in the form of a masterbatch dispersed in a mixed binder resin of the first binder resin and the second binder resin used. The addition amount of the masterbatch may be an amount such that the amount of the colorant contained is within the above range. The colorant content in the masterbatch is preferably 20 to 40% by weight.

(Charge control agent)
In the toner of the present invention, a known charge control agent conventionally used in full color toners may be used.
For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus Simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used. As the charge control agent, a metal salt of salicylic acid or a derivative thereof is particularly preferable.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(External additive)
In the present invention, other inorganic fine particles can be used as an external additive for assisting fluidity, developability and chargeability in combination with the aforementioned magnesium silicate compound.
Specific examples of the inorganic fine particles include, for example, silicon oxide, zinc oxide, tin oxide, silica sand, titanium oxide, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, Examples thereof include aluminum oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
The total amount of the external additive in the present invention is preferably 1.0 to 5.0 parts by mass with respect to 100 parts by mass of the toner base. When the total amount of the external additive is larger than the above range, fogging, developability and fixing separation properties are deteriorated. When the total amount of external additives is less than the above range, fluidity, transferability, and heat-resistant storage properties are deteriorated.

(Manufacturing method)
The toner of the present invention is a toner having a desired particle size by mixing, kneading, pulverizing, and classifying the first binder resin, the second binder resin, and the colorant in which the hydrocarbon wax is internally added by a conventional method. Particles (colored resin particles) can be obtained and mixed with an external additive. The average particle size of the toner particles is 4 to 10 μm, preferably 5 to 10 μm.
Further, the toner of the present invention integrally supports at least one unit selected from an electrostatic latent image holding member, a charging unit, a developing unit, and a cleaning unit and is detachably attached to the image forming apparatus main body. -It can be used by being held in the developing means in the bridge.

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

<Measurement and evaluation method>
First, a method for measuring physical properties of the used material and a method for evaluating the obtained sample will be described.
(Evaluation)
(Toner particle size (Coulter))
A method for measuring the particle size distribution of the toner particles will be described. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below. First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of the measurement sample is further added as a solid content. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Dv) and the number average particle diameter (Dp) of the toner can be obtained. As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

(Softening point (Tm))
Using a flow tester (CFT-500 / manufactured by Shimadzu Corporation), 1.5 g of a measurement sample was weighed, and using a die of H1.0 mm × φ1.0 mm, the heating rate was 3.0 ° C./min, and the preheating time was 180. Measurement was performed under the conditions of seconds, a load of 30 kg, and a measurement temperature range of 80 to 140 ° C., and the temperature at which the above sample flowed out 1/2 was taken as the softening point.

(Inorganic fine particle size measurement)
The primary particle size was obtained by embedding inorganic fine particles with a resin, creating a flake with a microtome, and measuring the particle size by TEM observation.
The secondary particle size is 2 to 20 mg with a laser diffraction / scattering type particle size distribution measuring device (LA-920 / manufactured by Horiba Seisakusho), 0.1 to 5 ml of a surfactant added as a dispersant, and the measurement sample as a solid content. Add. The liquid in which the sample was suspended was subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measured with the measuring device.

(Actual machine evaluation)
Using a Ricoh Co., Ltd. IPSiO CX2500, a predetermined print pattern with a print rate of 6% was continuously developed for 3000 sheets in an N / N environment (23 ° C., 45%) (state of leakage, streaks). Charger stains and copy images (ground stains, image density) were visually observed and evaluated. Judgment criteria are as follows.
○ Good △ No problem in actual use × NG in actual use

Next, the material used for producing the toner particles and the method for preparing the toner particles will be described.
(Creation of magnesium silicate compound)
Mg (OH) ₂ powder slurry and SiO ₂ powder (average primary particle size 0.02 μm) were weighed to 2: 1 with MgO: SiO ₂ (molar ratio), MgO concentration 71.5 g / L, SiO 2 ₂ Using a sand grinder mill with 0.8 mmφ alumina silica beads, the media filling rate is 80%, the feeding speed is 4.0 L / min, and the number of slurry passes. Wet pulverization was performed under conditions of 3 passes. The slurry was spray-dried with a spray dryer and fired at 1100 ° C. for 30 minutes in the air in an electric furnace. Then, the fired product is slurried to 300 g / L, 50 L is sand grinder mill, 0.8 mmφ alumina silica-based beads are used as media, the media filling rate is 80%, and the liquid feeding speed is 5.6 L / The wet pulverization was performed under the conditions of min and the number of slurry passes of 2 passes. The slurry was spray-dried with a spray dryer and pulverized with a sand mill to obtain forsterite.
When the powder obtained as described above was identified by X-ray diffraction, it was a single phase of forsterite. The average primary particle size was 0.10 μm, the specific surface area was 18.9 m ² / g, and the average secondary particle size was 0.39 μm.

(Creation of inorganic fine particles)
NaOH is added to an aqueous slurry in which 100 g of forsterite prepared above is dispersed in 1 liter of pure water until pH = 10. While heating the slurry, 1.0 g of sodium stearate is added, and then HCl is added until pH = 2, stearic acid is precipitated with inorganic fine particles as nuclei, and the solution after the reaction is removed and washed. The obtained forsterite was dried, crushed with a jet mill, and passed through a 105 μm sieve to obtain forsterite (external additive 1) having a surface treated with 1% by weight of stearic acid.
Hereinafter, external additives 2 to 4 and 6 to 9 were obtained in the same manner as the external additive 1 except that the inorganic fine particles, the surface treatment agent, and the addition amount shown in Table 1 were employed. However, the external additive 6 had a low surface activity of the silane coupling agent and hardly adhered to the surface of the forsterite.
The external additive 5 is the forsterite itself produced as described above.

(Creation of first binder resin)
As a vinyl monomer, 600 g of styrene, 110 g of butyl acrylate, 30 g of acrylic acid, and 30 g of dicumyl peroxide as a polymerization initiator were placed in a dropping funnel. Among polyester monomers, as polyols, 1230 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4 -Hydroxyphenyl) propane 290 g, isododecenyl succinic anhydride 250 g, terephthalic acid 310 g, 1,2,4-benzenetricarboxylic anhydride 180 g, dibutyltin oxide 7 g as esterification catalyst, wax as paraffin wax (melting point 73.3 ° C., differential 340 g (11.0 parts by weight with respect to 100 parts by weight of charged monomer) of 340 g of endothermic peak at the time of temperature rise measured by a scanning calorimeter at 4 ° C., thermometer, stainless steel stirrer, flow-down condenser, Place in a 5 liter four-necked flask equipped with a nitrogen inlet tube and a mantle heater In a nitrogen atmosphere, with stirring at a temperature of 160 ° C., it was added dropwise over one hour a mixture of the vinyl monomer resins and the polymerization initiator from the dropping funnel. The addition polymerization reaction was aged for 2 hours while maintaining the temperature at 160 ° C., and then the temperature was raised to 230 ° C. to perform the condensation polymerization reaction. The degree of polymerization was tracked by the softening point measured using a constant load extrusion capillary rheometer, and when the desired softening point was reached, the reaction was terminated to obtain Resin H1. The resin softening point was 130 ° C.

(Creation of second binder resin)
As polyol, 2210 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 850 g of terephthalic acid, 120 g of 1,2,4-benzenetricarboxylic anhydride and dibutyltin oxide 0 as esterification catalyst .5 g was put into a 5 liter four-necked flask equipped with a thermometer, a stainless steel stirrer, a falling condenser and a nitrogen inlet tube, and the temperature was raised to 230 ° C. in a mantle heater under a nitrogen atmosphere to conduct a condensation polymerization reaction. It was. The degree of polymerization was monitored by the softening point measured using a constant load extrusion capillary rheometer, and when the desired softening point was reached, the reaction was terminated to obtain Resin L1. The resin softening point was 115 ° C.

(Create toner particles)
For 100 parts by mass (including the weight of the internally added wax) of the binder resin containing the first binder resin and the second binder resin in a ratio of 7: 3, C.I. I. After fully mixing a master batch equivalent to containing 4 parts by weight of Pigment Red 57-1 with a Henschel mixer, the one from which the discharge part of the biaxial extrusion kneader (PCM-30: manufactured by Ikekai Tekko Co., Ltd.) was removed was used. After melt-kneading, the obtained kneaded material was rolled to a thickness of 2 mm with a cooling press roller, cooled with a cooling belt, and then roughly pulverized with a feather mill. Then, after pulverizing with a mechanical pulverizer (KTM: Kawasaki Heavy Industries, Ltd.) to an average particle size of 10-12 μm, and further pulverizing with a jet pulverizer (IDS: Nippon Pneumatic Co., Ltd.) while classifying coarse particles. Then, fine powder classification was performed using a rotor type classifier (Teplex type classifier type: 100ATP: manufactured by Hosokawa Micron Corporation) to obtain colored resin particles 1. The average particle diameter of the colored resin particles 1 was 7.8 μm.

[Example 1]
1.0 part by mass of external additive 1 and 1.0 part by mass of silica RX200 are added to 100 parts by mass of the colored resin particles 1 obtained as described above, and a Henschel mixer (circumferential speed 40 m / sec, 60 seconds). ) A magenta toner 1 was obtained by mixing.
Table 2 shows the evaluation results of the obtained toner.

[Examples 2-7, Comparative Examples 1-6]
Hereinafter, magenta toners 2 to 13 of Examples 2 to 7 and Comparative Examples 1 to 6 were obtained in the same manner as Example 1 except that the external additives listed in Table 1 were used.
Table 2 shows the evaluation results of the obtained toner.

  By using the toner of the present invention, background contamination does not occur, and toner leakage of supply toner due to toner reset failure on the developing roller, conveyance surface streaks due to electrostatic aggregation, and charger contamination are suppressed. In addition, since excellent image stability can be obtained, the toner can be suitably used as an electrostatic charge developing toner for use in a copying machine, a printer, or the like to which electrophotographic technology is applied.

Claims (5)

A toner obtained by externally adding inorganic fine particles to a toner base having at least a binder resin and a colorant, wherein the inorganic fine particles are forsterite fine particles surface-treated with a fatty acid. The toner according to claim 1, wherein the fatty acid is a fatty acid represented by the following general formula (2).
C _n H _{2n + 1} COOH (2)
(N = 10-25) The forsterite fine particles have an average primary particle size of 0.05 μm to 0.15 μm , an average secondary particle size of 0.2 μm to 0.6 μm , and 0.05 to 2 mass relative to 100 parts by mass of the toner base. The toner according to claim 1, wherein a part of the toner is added. In an image forming method of forming a color image with a toner obtained by externally adding inorganic fine particles to a toner base having at least a binder resin and a colorant, the image forming method includes at least an electrostatic latent image for holding an electrostatic latent image. An electrostatic latent image forming step of forming an electrostatic latent image on the primary charged electrostatic latent image holding body, and a plurality of developing devices having the electrostatic latent image for each color. A developing step by a one-component developing method for developing with toner and forming a toner image on the electrostatic latent image holding member, a transferring step for transferring the toner images of each color formed on the latent image holding member to a recording material, and is the toner image transferred to the recording material as it has a fixing step of fixing to the recording material, non-magnetic, characterized in that said toner is a toner according to any one of claims 1 to 3 One-component image forming method. In a process cartridge that integrally supports an electrostatic latent image holding member and at least one unit selected from a charging unit, a developing unit, and a cleaning unit and is detachable from the main body of the image forming apparatus, the developing unit holds toner. and, the toner, the process cartridge, which is a toner according to any one of claims 1-3.