JP2015004815A - Electrostatic charge image developer, developer cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrostatic charge image developer configured to prevent image defect and to form an image with reduced density variation even in a high-temperature and high-humidity environment.SOLUTION: Electrostatic charge image developer contains: toner having a toner base particle containing a binder resin at least and formed by externally adding an external additive having a number average particle diameter of 80-500 nm to a surface of the toner base particle; and a porous elastomer particle having a number average particle diameter of 1-30 μm. The porous elastomer particle contains an ionic liquid.

Description

The present invention relates to an electrostatic charge image developer, a developer cartridge, a process cartridge, an image forming apparatus, and an image forming method.
About.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image (electrostatic latent image) is formed on a photoreceptor (image carrier) by charging and exposure processes, the electrostatic latent image is developed with a developer containing toner, and a transfer and fixing process. It is visualized through. The developer used here includes a two-component developer comprising a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone. The toner is usually produced by using a thermoplastic resin as a pigment. In addition, a kneading and pulverizing method is used in which melt-kneading is performed together with a release agent such as a charge control agent and wax, cooling, pulverization, and further classification. In these toners, if necessary, inorganic and organic particles for improving fluidity and cleaning properties may be added to the toner particle surfaces.

Examples of conventional toners include toners described in Patent Documents 1 to 3.
Patent Document 1 discloses an electrophotographic toner comprising toner particles and spherical particles having a volume average particle diameter of 80 to 300 nm and having a surface treated with silicone oil as an external additive. Yes.
In Patent Document 2, a toner for electrostatic charge image development containing at least a binder resin, a carboxylic acid and a colorant and an external additive has a number average primary particle diameter of 10 to 30 nm treated with silicone oil. A toner for developing electrostatic images characterized by containing 0.1 to 2.0% by mass of alumina particles is described.
Patent Document 3 describes a toner composition for developing an electrostatic image, wherein resin particles treated with oil are added to toner particles containing a binder and a colorant.

JP 2007-279244 A JP 2009-265471 A JP-A-8-202075

An object of the present invention is to provide an electrostatic charge image developer capable of suppressing the occurrence of image defects even under a high temperature and high humidity environment and obtaining an image with little density fluctuation.
Another object of the present invention is to provide a developer cartridge, a process cartridge, an image forming apparatus, and an image forming method using the electrostatic image developer.

The above-described problems of the present invention are solved by means described in the following <1> and <5> to <8>. It is shown below with <2>-<4> which are preferable embodiments.
<1> a toner having toner base particles containing at least a binder resin, and an external additive having a number average particle size of 80 nm to 500 nm on the surface of the toner base particles, and a number average particle size 1 to 30 μm of porous elastomer particles, wherein the porous elastomer particles contain an ionic liquid,
<2> The electrostatic charge image developer according to <1>, wherein a total content of the ionic liquid in the electrostatic charge image developer is 0.1 mg or more and 30 mg or less with respect to 1 g of the toner.
<3> The electrostatic charge image developer according to <1> or <2>, wherein the electric conductivity of the ionic liquid in the electrostatic charge image developer is 1.0 mS / cm or more and 20 mS / cm or less. ,
<4> The electrostatic charge image developer according to any one of the above <1> to <3>, wherein the number average particle diameter of the porous elastomer particles is 5 μm or more and 15 μm or less.
<5> A developer cartridge containing the electrostatic charge image developer according to any one of <1> to <4> above,
<6> A process cartridge comprising a developer holder that contains the electrostatic charge image developer according to any one of the above items <1> to <4> and holds and conveys the electrostatic charge image developer.
<7> Image carrier, charging unit for charging the image carrier, exposure unit for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier, and development including toner Developing means for developing the electrostatic latent image with an agent to form a toner image, transfer means for transferring the toner image from the image holding member to the surface of the transfer target, and toner transferred to the surface of the transfer target The electrostatic charge image developer according to any one of <1> to <4>, further comprising: a fixing unit that fixes an image; and a cleaning unit that cleans the image carrier with a cleaning blade. An image forming apparatus,
<8> A latent image forming step of forming an electrostatic latent image on the surface of the image carrier, and a developing step of developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image. A transfer step of transferring the toner image to the surface of the transfer member, a fixing step of fixing the toner image transferred to the surface of the transfer member, and a developer remaining on the image carrier being cleaned by a cleaning blade. An image forming method using the electrostatic charge image developer according to any one of <1> to <4> above as a developer.

According to the invention described in <1> above, compared to the case where the present configuration is not provided, the occurrence of image defects can be suppressed even in a high-temperature and high-humidity environment, and an image that can obtain an image with less density fluctuation can be obtained. A charge image developer can be provided.
According to the invention described in <2> above, the total content of the ionic liquid in the electrostatic image developer is higher than that in the case where the total content of the ionic liquid is less than 0.1 mg or more than 30 mg with respect to 1 g of the toner. Even in a high humidity environment, it is possible to provide an electrostatic charge image developer that can further suppress the occurrence of image defects and obtain an image with less density fluctuation.
According to the invention described in the above <3>, the electric conductivity of the ionic liquid in the electrostatic charge image developer is higher than that in a case where the electric conductivity is less than 1.0 mS / cm or more than 20 mS / cm. Even under the environment, it is possible to provide an electrostatic charge image developer that can further suppress the occurrence of image defects and obtain an image with less density fluctuation.
According to the invention described in <4> above, when the number of externally added particles is larger than that in the case where the number average particle diameter of the porous elastomer particles is less than 5 μm or more than 15 μm, in a high temperature and high humidity environment. Even if it exists, the electrostatic charge image developer which can suppress generation | occurrence | production of an image defect more can be provided.
According to the invention described in <5> above, compared to a case where the present configuration is not provided, the occurrence of image defects can be suppressed even in a high-temperature and high-humidity environment, and an image that can obtain an image with less density fluctuation can be obtained. A developer cartridge containing a charge image developer can be provided.
According to the invention described in <6> above, compared to the case without this configuration, the occurrence of image defects can be suppressed even in a high-temperature and high-humidity environment, and an image that can obtain an image with less density fluctuation can be obtained. A process cartridge containing a charge image developer can be provided.
According to the invention described in the above <7>, compared with the case where the present configuration is not provided, an image that can suppress the occurrence of an image defect and obtain an image with less density fluctuation even in a high temperature and high humidity environment. A forming apparatus can be provided.
According to the invention described in <8> above, compared to the case where the present configuration is not provided, an image that can suppress the occurrence of an image defect and obtain an image with less density variation even in a high temperature and high humidity environment. A forming method can be provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus preferably used in the present embodiment. It is a schematic block diagram which shows an example of the process cartridge used suitably for this embodiment.

  Hereinafter, the present embodiment will be described.

(1) Electrostatic Charge Image Developer The electrostatic charge image developer (also referred to simply as “developer”) of the present embodiment has toner base particles containing at least a binder resin, and is formed on the surface of the toner base particles. Containing a toner externally added with an external additive having a number average particle diameter of 80 nm to 500 nm, and porous elastomer particles having a number average particle diameter of 1 μm to 30 μm, wherein the porous elastomer particles are It contains an ionic liquid.
Moreover, it is preferable that the electrostatic charge image developer of this embodiment further contains a carrier.

In the electrophotographic method, the external additive released from the toner is cleaned on the image holding member (also referred to as “photosensitive member”). An example in which an additive is added and oil is supplied onto the image carrier is given.
However, as a result of detailed studies by the present inventors, the external additive treated with oil tends to deteriorate the fluidity of the toner as the amount added to the toner increases, and there is a trade-off relationship with the cleaning characteristics. (Trade-off relationship). Particularly in a high-temperature and high-humidity environment (for example, 30 ° C. and 85% RH), the fluidity of the toner is reduced. The present inventors have found that the image density decreases and the image density decreases.
As a result of further detailed studies, the present inventors have found that, unlike conventional oil-treated external additives, porous elastomer particles containing an ionic liquid are added to the electrostatic charge image developer.
The electrostatic charge image developer according to the exemplary embodiment adds the porous elastomer particles containing the ionic liquid to the electrostatic charge image developer so that the ionic liquid does not easily adhere to the toner. And is supplied to the image carrier during toner development, and the ionic liquid is supplied by applying pressure to the porous elastomer particles by the cleaning means.

Since the supplied ionic liquid has ions having a polarity opposite to that of the external additive, the ionic liquid adheres to the external additive electrostatically strongly attached on the image carrier, and the adhesion force of the external additive to the image carrier Is considered to improve the cleaning characteristics of the image carrier. Therefore, it is presumed that the developer of this embodiment can suppress the occurrence of image defects and obtain an image with less density fluctuation compared to the case where a conventional oil-treated external additive is applied.
In particular, compared to the case where an oil-treated external additive is applied, the deterioration of toner fluidity is suppressed, and the density followability is excellent. For this reason, even when an image from a low image density (low area coverage) to a high image density (high area coverage) is created, it is estimated that the decrease in image density is suppressed.

(Porous elastomer particles)
The electrostatic image developer of this embodiment contains porous elastomer particles having a number average particle diameter of 1 μm or more and 30 μm or less, and the porous elastomer particles contain an ionic liquid. In addition, this number average particle diameter is a particle diameter about the primary particle of a porous elastomer particle.
The number average particle diameter of the porous elastomer particles in the present embodiment is 1 μm or more and 30 μm or less, and preferably 5 μm or more and 15 μm or less. Within the above range, even in a high-temperature and high-humidity environment (for example, 30 ° C. and 85% RH), the occurrence of image defects is further suppressed, and an image with less density fluctuation can be obtained.
Further, if the number average particle diameter of the porous elastomer particles is less than 1 μm, it is externally added onto the toner, the fluidity of the toner itself is remarkably deteriorated, and the image density is lowered. When creating an image of (coverage), a decrease in image density is remarkable. When the number average particle diameter of the porous elastomer particles exceeds 30 μm, the supply of the ionic liquid to the photoreceptor becomes insufficient, filming occurs on the photoreceptor, and an image defect occurs.
The number average particle diameter of the porous elastomer particles in the developer was measured by observing 100 primary particles with a scanning electron microscope SEM (Scanning Electron Microscope) apparatus (manufactured by Hitachi, Ltd .: S-4100). Then, this image is taken into an image analysis apparatus (LUZEX III, manufactured by Nireco Co., Ltd.) and calculated as a number average particle diameter of a circle-equivalent diameter obtained by image analysis of primary particles. In the electron microscope, the magnification is adjusted so that about 10 or more and 50 or less porous elastomer particles are captured in one field of view, and the equivalent circle diameter of the primary particles is determined by observing a plurality of fields of view.

The material of the porous elastomer particles is not particularly limited as long as it is a so-called elastomer that has a property of being deformed by an external force and recovering when the external force is removed, and includes various known elastomers. Specifically, for example, synthetic rubber such as urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, EPDM (ethylene-propylene-diene copolymer rubber), epichlorohydrin rubber, polyolefin, polystyrene, polyvinyl chloride, etc. Synthetic resins and the like.
Among these, from the viewpoint of easily producing porous elastomer particles by emulsion polymerization, a styrene-based resin is preferable, a copolymer of styrene and a crosslinking agent is more preferable, and a copolymer of styrene and divinylbenzene is used. More preferably.

Since the porous elastomer particles include an ionic liquid, the porous elastomer particles may be particles having at least a plurality of pores on the particle surface, and the specific surface area of the porous elastomer particles is from 0.1 m2 / g to 25 m2 / g. Preferably, it is 0.3 m2 / g or more and 20 m2 / g or less, and more preferably 0.5 m2 / g or more and 15 m2 / g or less. Within the above range, the ionic liquid is sufficiently supplied to the photoreceptor, and the occurrence of image defects is further suppressed.
The BET method is used as a method for measuring the specific surface area of the porous elastomer particles.
Specifically, using porous elastomer particles separated from the developer, using a specific surface area pore distribution measuring device (SA3100, manufactured by Beckman Coulter, Inc.), 0.1 g of a measurement sample is precisely weighed and placed in a sample tube. After that, it is degassed and obtained by multipoint automatic measurement.

The electric conductivity of the ionic liquid contained in the porous elastomer particles is preferably 0.5 mS / cm or more and 30 mS / cm or less, and more preferably 1.0 mS / cm or more and 20 mS / cm or less. Within the above range, even in a high-temperature and high-humidity environment (for example, 30 ° C. and 85% RH), the occurrence of image defects is further suppressed, and an image with less density fluctuation can be obtained. The electrical conductivity of the ionic liquid was measured with MPC227 (pH / Conductivity Meter, manufactured by Mettler Trend).
The ionic liquid contained in the porous elastomer particles is preferably a compound having a melting point of less than 20 ° C., that is, a compound that is liquid at 20 ° C. And it is preferable that the boiling point of an ionic liquid is 150 degreeC or more, and it is more preferable that it is 200 degreeC or more.
Moreover, the ionic liquid which a porous elastomer particle contains may be contained individually by 1 type, or may contain 2 or more types.
The ionic liquid is a salt composed of an anion and a cation counterion, and indicates a liquid compound under normal temperature and normal pressure (25 ° C., 1.0 × 105 Pa).
Examples of ionic liquids include imidazolium types such as ethylmethylimidazolium and butylmethylimidazolium as cation species and pyridinium types such as methylpyridinium and ethylpyridinium, and tetrafluoroborate ions and trifluoromethylsulfonylimide ions as anion species. An ionic liquid using Among these, for example, an ionic liquid using ethylmethylimidazolium as the cationic species is preferable, and an ionic liquid using tetrafluoroborate ions as the anionic species is more preferable.

Further, the total content of the ionic liquid in the electrostatic charge image developer of the present embodiment is preferably 0.01 mg or more and 100 mg or less, and 0.05 mg or more with respect to 1 g of the toner in the electrostatic charge image developer. More preferably, it is 50 mg or less, and further preferably 0.1 mg or more and 30 mg or less. Within the above range, even in a high-temperature and high-humidity environment (for example, 30 ° C. and 85% RH), the occurrence of image defects is further suppressed, and an image with less density fluctuation can be obtained.
As a method for measuring the total content of the ionic liquid with respect to 1 g of the porous elastomer particles in the electrostatic image developer of the present embodiment, the porous elastomer particles are ultrasonically washed in hexane (output 60 W, frequency 20 kHz, 30 minutes), and the operation of removing the ionic liquid by filtering the washing liquid is repeated 5 times, followed by vacuum drying at 60 ° C. for 12 hours. Then, the content of the ionic liquid in the porous elastomer particles is calculated from the weight change before and after the removal of the ionic liquid, and the total content of the ionic liquid with respect to 1 g of toner is calculated from the amount of the porous elastomer particles added to the toner. .

  The content of the porous elastomer particles in the electrostatic image developer of the present embodiment is such that the ionic liquid is sufficiently supplied to the photoreceptor and the total mass of the electrostatic image developer from the viewpoint of suppressing the occurrence of image defects. On the other hand, it is preferably 0.05% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 3% by mass or less, and more preferably 0.1% by mass or more and 2% by mass or less. More preferably, it is particularly preferably 0.2% by mass or more and 1% by mass or less.

-Method for producing porous elastomer particles-
The method for producing the porous elastomer particles is not particularly limited, and a known method may be used. For example, a method of processing a porous elastomer material into particles, a pore-forming agent when producing an elastomer by emulsion polymerization And a method of removing the pore-forming agent after emulsion polymerization. Among these, from the viewpoint of easy production of spherical particles, a method in which a pore-forming agent is mixed with emulsion particles when the elastomer is produced by emulsion polymerization, and the pore-forming agent is removed after emulsion polymerization is preferred. It is done.
Examples of the pore forming agent include a compound that is solid during emulsion polymerization and removed by at least one of dissolution and decomposition after emulsion polymerization, and a diluent that does not participate in the polymerization reaction during emulsion polymerization.
As a compound that is solid during emulsion polymerization and is removed by at least one of dissolution and decomposition after emulsion polymerization, for example, calcium carbonate is preferable from the viewpoint of cost and availability. Calcium carbonate has low solubility in water and decomposes while releasing carbon dioxide when it comes into contact with an acidic solution.
Although there is no restriction | limiting in particular as a diluent, Diethylbenzene, isoamyl alcohol, etc. are mentioned preferably.
Moreover, it is preferable that the usage-amount of a diluent is larger than the usage-amount of a polymeric compound.
The shape of the pore-forming agent is preferably particulate, and the number average particle diameter is preferably 5 nm to 200 nm, and more preferably 5 nm to 100 nm.
Moreover, there is no restriction | limiting in particular as the conditions of the said emulsion polymerization, For example, what is necessary is just to carry out on the conditions of well-known emulsion polymerization except using a pore formation agent.

-Method of containing ionic liquid in porous elastomer particles-
There are no particular restrictions on the method of containing the ionic liquid in the porous elastomer particles. For example, the method of bringing the porous elastomer particles into contact with the ionic liquid, the ionic liquid dissolved in an organic solvent, the solution and the porous Preferred is a method of contacting the organic elastomer particles and removing the organic solvent.
The contact may be performed by a known method, for example, a method in which porous elastomer particles and an ionic liquid or an ionic liquid solution are mixed, or a porous elastomer particle is added to an ionic liquid or an ionic liquid solution. The method of immersing etc. is mentioned preferably.
The organic solvent is not particularly limited as long as it dissolves an ionic liquid, and preferred examples thereof include hydrocarbon solvents and alcohols.

(toner)
The electrostatic image developer of this embodiment has toner base particles containing at least a binder resin. Further, it contains a toner (also referred to as “electrostatic image developing toner”) in which particles having a number average particle diameter of 80 nm to 500 nm are externally added to the surface of the toner base particles.

<Toner base particles>
In this embodiment, the toner base particles contain at least a binder resin. In addition to these components, the toner base particles may contain other components such as a colorant and a release agent.

-Binder resin-
The binder resin is not particularly limited. For example, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, acrylic Esters having vinyl groups such as lauryl acid, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; monomers such as polyolefins such as ethylene, propylene and butadiene Comprising homopolymers or copolymers obtained by combining two or more of these, even like and mixtures thereof. In addition, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or a mixture of these with the vinyl resin, or vinyl monomers in the presence of these resins Examples thereof include a graft polymer obtained by polymerization.

Styrene resin, (meth) acrylic resin, and styrene- (meth) acrylic copolymer resin are obtained by known methods, for example, by combining styrene monomers and (meth) acrylic acid monomers alone or in appropriate combination. It is done. “(Meth) acryl” is an expression including both “acryl” and “methacryl”.
The polyester resin can be obtained by selecting and combining suitable ones from a dicarboxylic acid component and a diol component, and synthesizing them using a conventionally known method such as a transesterification method or a polycondensation method.

  When using a styrene resin, a (meth) acrylic resin or a copolymer resin thereof as a binder resin, the weight average molecular weight Mw is 20,000 or more and 100,000 or less, and the number average molecular weight Mn is 2,000 or more and 30,000 or less. It is preferable to use the thing of the range. On the other hand, when a polyester resin is used as the binder resin, a resin having a weight average molecular weight Mw of 5,000 or more and 40,000 or less and a number average molecular weight Mn of 2,000 or more and 10,000 or less may be used. preferable.

The glass transition temperature of the binder resin is preferably in the range of 40 ° C. or higher and 80 ° C. or lower. When the glass transition temperature is in the above range, the minimum fixing temperature is easily maintained.
A differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC50) was used to measure the glass transition temperature Tg of the resin.

-Colorant-
The toner base particles preferably contain a colorant.
The colorant may be a dye or a pigment, but a pigment is used from the viewpoint of light resistance and water resistance. Further, the colorant is not limited to a colored colorant, and includes a white colorant and a colorant having a metal color.
Examples of colorants include carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, and rose. Bengal, Quinacridone, Benzidine Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. A known pigment such as CI Pigment Blue 15: 3 is used.

In the exemplary embodiment, the content of the colorant in the toner base particles is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.
It is also effective to use a surface-treated colorant or a pigment dispersant. By selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like are prepared.

-Release agent-
The toner base particles preferably contain a release agent.
The release agent is not particularly limited, and known ones are used. For example, paraffin wax and derivatives thereof, montan wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof Derivatives and the like. Derivatives include oxides, polymers with vinyl monomers, and graft modified products. In addition, alcohols, fatty acids, plant waxes, animal waxes, mineral waxes, ester waxes, acid amides and the like are also used. The melting temperature of these release agents is preferably 50 ° C. or higher and 140 ° C. or lower.
The content of the release agent in the toner base particles is preferably from 0.5% by mass to 15% by mass, and more preferably from 1.0% by mass to 12% by mass.

-Other additives-
In addition to the above components, various components such as an internal additive and a charge control agent may be added to the toner base particles according to the exemplary embodiment as necessary.
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese, alloys, and magnetic materials such as compounds containing these metals.
Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

-External additive-
In the toner used in the exemplary embodiment, particles having a number average particle size of 80 nm to 500 nm (also referred to as “external additive”) are externally added to the surface of the toner base particles. In addition, this number average particle diameter is a particle diameter about the primary particle of an external additive.
The external additive used in the present embodiment is a particle having a number average particle size of 80 nm to 500 nm, preferably a number average particle size of 90 nm to 300 nm, and a number average particle size of 100 nm to 250 nm. The following particles are more preferable, and the number average particle diameter is more preferably 100 nm to 200 nm. When the number average particle diameter of the external additive is less than 80 nm, the external additive is buried with time, and the image quality density is likely to be lowered. On the other hand, if it exceeds 500 nm, the fluidity of the toner is remarkably lowered, and the image density tends to be lowered when an image having a high image density (high area coverage) is created. On the other hand, when the number average particle diameter of the external additive is in the above range, an image with less density fluctuation can be obtained even in a high temperature and high humidity environment (for example, 30 ° C. and 85% RH).
The number average particle size of the external additive is suitably measured by Coulter Multisizer II (manufactured by Beckman Coulter, Inc.) when using the external additive separated from the toner. When the toner is directly observed and used, 100 primary particles are observed with a scanning electron microscope SEM (Scanning Electron Microscope) apparatus (manufactured by Hitachi, Ltd .: S-4100), and an image is taken. It is taken into an image analyzer (LUZEXIII, manufactured by Nireco Co., Ltd.) and calculated as the number average particle diameter of the equivalent circle diameter obtained by image analysis of primary particles. Note that the magnification of the electron microscope is adjusted so that about 10 to 50 or less of the first external additive can be seen in one visual field, and the equivalent circle diameter of the primary particles is obtained by observing multiple visual fields.

The material of the external additive is not particularly limited, and known inorganic particles and organic particles are used as the external additive of the toner. For example, silica, alumina, titanium oxide (titanium oxide, metatitanic acid, etc.), oxidation Examples thereof include inorganic particles such as cerium, zirconia, calcium carbonate, magnesium carbonate, calcium phosphate, and carbon black, and resin particles such as vinyl resin, polyester resin, and silicone resin. Among these, the external additive is particularly preferably silica particles.
Examples of the silica particles include fumed silica, colloidal silica, silica gel and the like, and are used without particular limitation.
Further, the external additive may be subjected to a hydrophobizing treatment with, for example, a silane coupling agent described later.
The hydrophobic treatment may be performed by immersing particles in a hydrophobic treatment agent. Although there is no restriction | limiting in particular as said hydrophobic treatment agent, For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, silane coupling agents are preferable.

As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used.
Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- ( Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane , Γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Examples thereof include propyltrimethoxysilane and γ-chloropropyltrimethoxysilane.

  The amount of the hydrophobizing agent varies depending on the type of the particles and cannot be defined unconditionally, but is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the particles. More preferably, it is 20 parts by mass or more. In the present embodiment, commercially available products are also preferably used as the hydrophobic silica particles that have been subjected to a hydrophobic treatment.

In addition, in the toner used in the exemplary embodiment, the external additive has a number average particle diameter of 80 nm or more and 500 nm or less. Also good.
In the toner used in the exemplary embodiment, the content of particles having a number average particle size of 80 nm to 500 nm as an external additive is not particularly limited, but is 0.3% by mass to 35% with respect to the total mass of the toner. It is preferably at most mass%, more preferably at least 1 mass% and at most 30 mass%, further preferably at least 3 mass% and at most 25 mass%.

-Toner production method-
The toner base particles used in the exemplary embodiment are not particularly limited by the production method, and a known method is used. Specific examples include the following methods.
The production of the toner base particles is obtained, for example, by a kneading and pulverizing method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are kneaded, pulverized, and classified; To change the shape of the particles by mechanical impact force or thermal energy; dispersion of emulsified binder resin, dispersion of colorant, release agent, and charge control agent as required An emulsion and aggregation method in which toner base particles are obtained by mixing and aggregating and heating and fusing the solution; emulsion polymerization of a polymerizable monomer of a binder resin, and the formed dispersion, a colorant, a release agent, And, if necessary, a dispersion of a charge control agent or the like is mixed, agglomerated and heat-fused to obtain toner mother particles; an emulsion polymerization aggregation method; a polymerizable monomer for obtaining a binder resin, and coloring Suspension polymerization method in which an agent, a release agent and, if necessary, a solution such as a charge control agent are suspended in an aqueous solvent A binder resin and a colorant, releasing agent, and dissolution suspension method and granulated with a solution such as a charge control agent is suspended in an aqueous solvent optionally; or the like is used. In addition, a manufacturing method may be performed in which the toner base particles obtained by the above method are used as a core, and aggregated particles are further adhered and heat-fused to have a core-shell structure.
Examples of the external addition method of the external additive in the toner used in the exemplary embodiment include a method in which the toner base particles and the external additive are mixed by a Henschel mixer or a V blender. Further, when the toner base particles are produced by a wet method, they are externally added by a wet method.
Among these, the toner used in the exemplary embodiment is preferably a toner (emulsion aggregation toner) obtained by an emulsion aggregation method or an emulsion polymerization aggregation method.

The toner base particles produced as described above have a volume average particle size of preferably 2 μm or more and 8 μm or less, more preferably 3 μm or more and 7 μm or less. When the volume average particle size is 2 μm or more, the fluidity of the toner is good and sufficient charging ability is imparted from the carrier, so that fogging in the background portion and density reproducibility are unlikely to occur. . Further, when the volume average particle size is 8 μm or less, the effect of improving the reproducibility, gradation and graininess of fine dots is good, and a high-quality image can be obtained. The volume average particle diameter is measured with Coulter Multisizer II (manufactured by Beckman Coulter, Inc.).
As a measuring method, first, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 ml to 150 ml of the electrolytic solution. Added. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size is 2.0 μm or more and 60 μm or less using the Coulter Multisizer II with an aperture having an aperture diameter of 100 μm. The particle size distribution of particles in the range was measured. The number of particles to be measured was 50,000.
In the measured particle size distribution, a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size at which 50% is accumulated is defined as the volume average particle size.

  The toner base particles are preferably pseudo-spherical from the viewpoint of improving developability and transfer efficiency and improving image quality. The sphericity of the toner base particles is expressed by using the shape factor SF1 of the following formula. The average value (average shape factor) of the shape factor SF1 of the toner base particles used in the present embodiment is less than 160. Preferably, it is in the range of 115 or more and less than 155, more preferably in the range of 120 or more and less than 140. When the average value of the shape factor SF1 is less than 160, good transfer efficiency is obtained and the image quality is excellent.

Formula: SF1 = (ML ² / A) × (π / 4) × 100

In the above formula, ML represents the maximum length of each toner base particle, and A represents the projected area of each toner base particle.
The average value of the shape factor SF1 (average shape factor) is obtained by taking 1,000 toner images magnified 250 times from an optical microscope into an image analyzer (LUZEX III, manufactured by Nireco Corporation) and the maximum length thereof. And the value of the SF1 for each particle obtained from the projected area and averaged.

(Career)
In the present embodiment, the development method is not particularly defined, but a two-component development method is preferable, and the electrostatic charge image developer of the present embodiment preferably contains a carrier.
The carrier is not particularly defined, but as the core material of the carrier, for example, magnetic metals such as iron, steel, nickel, cobalt, alloys of these with manganese, chromium, rare earth, etc., and magnetic oxidation such as ferrite, magnetite, etc. Among them, ferrite, particularly alloys with manganese, lithium, strontium, magnesium and the like are preferable from the viewpoint of core surface properties and core material resistance.

  The carrier used in this embodiment is preferably a carrier whose core material surface is coated with a resin. There is no restriction | limiting in particular as said resin, According to the objective, it selects suitably. Moreover, it is preferable that at least one of the resin particles and the conductive particles is dispersed in the resin. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. The average particle diameter of the resin particles is preferably 0.1 μm or more and 2 μm or less, and more preferably 0.2 μm or more and 1 μm or less. When the average particle size of the resin particles is 0.1 μm or more, the resin particles are excellent in dispersibility in the coating, whereas when the average particle size is 2 μm or less, the resin particles are not easily dropped from the coating.

The method for forming the coating is not particularly limited. For example, at least one of the resin particles such as crosslinkable resin particles and the conductive particles, and a styrene acrylic resin, a fluorine resin, or silicone as a matrix resin. Examples thereof include a method using a film-forming liquid containing a resin such as a resin in a solvent.
Specifically, the carrier core material is immersed in the film forming liquid, a spray method in which the film forming liquid is sprayed on the surface of the carrier core material, and the carrier core material is floated by flowing air And kneader coater method in which the film forming solution is mixed and the solvent is removed. Among these, the kneader coater method is preferable in the present embodiment.

  The mixing ratio of the toner and the carrier in the electrostatic charge image developer according to the exemplary embodiment is preferably 1 part by mass or more and 30 parts by mass or less, and 2 parts by mass or more and 10 parts by mass of the toner with respect to 100 parts by mass of the carrier. The following is more preferable. The method for preparing the electrostatic charge image developer is not particularly limited, and examples thereof include a method of mixing with a V blender.

(2) Image Forming Method The electrostatic image developer of this embodiment is used in an image forming method of an electrostatic image developing system (electrophotographic system).
The image forming method of the present embodiment may be an image forming method using the electrostatic charge image developer of the present embodiment, but the latent image forming step of forming an electrostatic latent image on the surface of the image carrier, the image carrier The electrostatic latent image formed on the surface is developed with a developer containing toner to form a toner image, the transfer step for transferring the toner image to the surface of the transfer target, and the image transferred to the surface of the transfer target The electrostatic charge image developer of this embodiment is applied as the developer, including a fixing step of fixing a toner image and a cleaning step of cleaning the developer remaining on the image carrier with a cleaning blade.

Each of the above steps is a general step per se, and is described in, for example, JP-A-56-40868 and JP-A-49-91231. Note that the image forming method of the present embodiment is preferably performed using an image forming apparatus such as a copier or a facsimile machine known per se.
The latent image forming step is a step of forming an electrostatic latent image on the surface of the image carrier (photoconductor).
The developing step is a step of developing the electrostatic latent image with a developer to form a toner image.
The transfer step is a step of transferring the toner image to the surface of the transfer target. In addition, examples of the transfer target in the transfer process include a recording medium such as an intermediate transfer member and paper.
Examples of the fixing step include a method of forming a copy image by fixing the toner image transferred onto the surface of the transfer paper by a heating roller fixing device in which the temperature of the heating roller is set to a constant temperature.
Preferably, the cleaning step includes a step of removing the electrostatic charge image developer remaining on the image carrier with a cleaning blade.
Preferred examples of the cleaning blade material include urethane rubber, neoprene rubber, and silicone rubber.
As the recording medium, known media can be used, for example, paper used for electrophotographic copying machines, printers, OHP sheets, etc. For example, the surface of plain paper is made of resin, etc. Coated coated paper, art paper for printing, etc. are preferably used.

  The image forming method of the present embodiment may further include a recycling step. The recycling step is a step of returning the electrostatic image developing toner collected in the cleaning step to the developer. The image forming method including the recycling process is performed using an image forming apparatus such as a toner recycling system type copying machine or facsimile machine. Further, the present invention may be applied to a recycling system that omits the cleaning process and collects toner simultaneously with development.

(3) Image Forming Apparatus The image forming apparatus of the present embodiment may have a developing unit that develops an electrostatic latent image with the electrostatic charge image developer of the present embodiment to form a toner image. The static image is formed by a holder, a charging unit for charging the image carrier, an exposure unit for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier, and a developer containing toner. A developing unit that develops the electrostatic latent image to form a toner image, a transfer unit that transfers the toner image from the image holding member to the surface of the transfer target, and a toner image transferred to the surface of the transfer target are fixed. The image forming apparatus includes a fixing unit and a cleaning unit that cleans the image carrier with a cleaning blade, and the electrostatic charge image developer according to the exemplary embodiment is applied as the developer.

  FIG. 1 is a schematic configuration diagram showing a quadruple tandem color image forming apparatus. The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed in a horizontal direction separated from each other by a predetermined distance. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

  Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are arranged away from each other in the left to right direction in the drawing. It is designed to travel in the direction toward 10K. The support roller 24 is applied with a force in a direction away from the driving roller 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the both. An intermediate transfer member cleaning unit 30 is provided on the side surface of the image carrier of the intermediate transfer belt 20 so as to face the driving roller 22. Further, in each of the units 10Y, 10M, 10C, and 10K, developing units (developing means) 4Y, 4M, 4C, and 4K, yellow, magenta, cyan, and black stored in toner cartridges 8Y, 8M, 8C, and 8K, respectively. The four colors of toner are supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K described above have the same configuration, here, the first image that forms the yellow image disposed on the upstream side in the intermediate transfer belt traveling direction is formed. The unit 10Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first unit 10Y instead of yellow (Y). Description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y has a photoreceptor 1Y that functions as an image carrier (photoreceptor). Around the photoreceptor 1Y, there is a charging roller (charging device, charging means) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential, and a laser beam 3Y based on an image signal obtained by color-separating the charged surface. An exposure device (exposure means) 3 that forms an electrostatic latent image by exposure, a developing device (development means) 4Y that develops the electrostatic latent image by supplying charged toner to the electrostatic latent image, and a developed toner image A primary transfer roller (primary transfer means) 5Y for transferring onto the intermediate transfer belt 20 and a cleaning device (cleaning means) 6Y for removing toner remaining on the surface of the photoreceptor 1Y after the primary transfer with a cleaning blade are arranged in this order. Has been.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20 and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

  Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described. First, prior to the operation, the surface of the photoreceptor 1Y is charged by the charging roller 2Y. A laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y. The electrostatic latent image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic latent image on the photoreceptor 1Y is converted into a visible image (developed image, toner image) by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer according to the present embodiment including at least yellow toner and a carrier is accommodated. As the surface of the photoreceptor 1Y passes through the developing device 4Y, yellow toner adheres electrostatically to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

  When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a primary transfer bias is applied to the primary transfer roller 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roller 5Y acts on the toner image. Then, the toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 20. On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by a cleaning means 6Y having a cleaning blade.

  Further, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit. Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 onto which the four color toner images have been transferred through the first to fourth units is arranged on the image transfer surface side of the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer means) 26 is connected to a secondary transfer portion. On the other hand, the recording paper (transfer object) P is fed at a predetermined timing to the gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via the supply mechanism, and the secondary transfer bias is supported. Applied to the roller 24, the toner image on the intermediate transfer belt 20 is transferred onto the recording paper P.

Thereafter, the recording paper P is fed to the pressure contact portion (nip portion) of the pair of fixing rolls in the fixing device (roll-type fixing means) 28, the toner image is heated, and the color-superposed toner image is melted to record the recording paper. Fixed onto P. The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus according to the present embodiment includes at least the image carrier, the charging unit, the exposure unit, the developing unit, the transfer unit, the fixing unit, and the cleaning unit. There is no particular limitation as long as the electrostatic charge image developer of the form is applied, but it may further include a charge eliminating means, if necessary.
In the transfer unit, the transfer may be performed twice or more using an intermediate transfer member. Examples of the transfer medium in the transfer unit include a recording medium such as an intermediate transfer medium and paper.

As the image carrier and each of the above-described units, the configurations described in the respective steps of the image forming method are preferably used. As each of the above-described means, a well-known means is used in the image forming apparatus. In addition, the image forming apparatus according to the present embodiment may include means and devices other than the above-described configuration. Further, the image forming apparatus according to the present embodiment may simultaneously perform a plurality of the above-described means.
The image forming apparatus according to the present exemplary embodiment further includes a cleaning unit that removes the electrostatic charge image developer remaining on the image holding member with a cleaning blade.

(4) Developer Cartridge and Process Cartridge The developer cartridge of this embodiment is a developer cartridge that accommodates the electrostatic charge image developer of this embodiment.
The process cartridge according to the present embodiment is a process cartridge including a developer holding body that accommodates the electrostatic charge image developer according to the present embodiment and holds and conveys the electrostatic charge image developer.

The developer cartridge of this embodiment is not particularly limited as long as it contains the electrostatic charge image developer of this embodiment. For example, the developer cartridge is attached to and detached from an image forming apparatus including a developing unit, and contains the electrostatic charge image developer of the present embodiment as a developer to be supplied to the developing unit.
The developer cartridge may be a cartridge that stores porous elastomer particles, toner, and a carrier. A cartridge that stores porous elastomer particles alone, a cartridge that stores toner alone, and a carrier that stores toner alone. The cartridge may be a separate body, or the cartridge that stores any two of the porous elastomer particles, the toner, and the carrier and the cartridge that stores the other one may be separated.
It is preferable that the process cartridge of the present embodiment is attached to and detached from the image forming apparatus.
In addition, the process cartridge according to the present embodiment may include other members such as a static elimination unit as necessary.
FIG. 2 is a schematic configuration diagram illustrating an example of an embodiment of a process cartridge according to the present embodiment. The process cartridge 200 uses a rail 116 on which a charging roller 108, a developing device 111, a cleaning unit 113 having a cleaning blade, an opening 118 for exposure, and an opening 117 for static elimination exposure are mounted together with the photosensitive member 107. Are combined and integrated. In FIG. 2, reference numeral 300 denotes a transfer target. The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus.
As the process cartridge, a known configuration may be adopted. For example, Japanese Patent Application Laid-Open No. 2008-209489 and Japanese Patent Application Laid-Open No. 2008-203736 are referred to.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to the following examples. Unless otherwise specified, “parts” and “%” represent “parts by mass” and “mass%”.

<Preparation of porous elastomer particles A to F>
Porous elastomer particles A to F were prepared as follows.
37.5 parts of styrene, 12.5 parts of divinylbenzene, 25 parts of diethylbenzene and 50 parts of isoamyl alcohol as a diluent, and 2.0 parts of dimethyl 2,2′-azobis (2-methylbutyronitrile) as a polymerization initiator Were mixed and dissolved. This mixture was put into a dispersion solution of 10 parts of calcium carbonate powder (number average particle size: 0.1 μm, TP-123 manufactured by Okutama Kogyo Co., Ltd.), 50 parts of sodium chloride, and 200 parts of water. After emulsification with a mixer at 6,000 rpm for 1 minute, a polymerization reaction was carried out at 70 ° C. for 20 hours in a nitrogen atmosphere. Thereafter, hydrochloric acid was added to decompose calcium carbonate, followed by washing with water, and then washing with ethanol to remove the diluent. Further, wet classification was performed to select elastomer particles A to F having a number average particle diameter of 0.5 μm, 1 μm, 5 μm, 15 μm, 30 μm, and 50 μm, and vacuum drying was performed at 100 ° C. for 12 hours. When the obtained elastomer particles A to F were observed, a large number of pores were observed, and the elastomer particles were porous. Thereafter, 150 parts of silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., model number: KM351) is dissolved in 1,000 parts of ethanol, and after stirring and mixing with 100 parts of elastomer particles, the solvent ethanol is removed using an evaporator. Porous elastomer particles A to F, which were dried and impregnated with an ionic liquid, were obtained. Here, the ionic liquid used for the impregnation treatment of the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate (10 mS / cm). The numbers in parentheses indicate the electrical conductivity of the ionic liquid. The number average particle diameters of the obtained porous elastomer particles A to F were measured by the above-described method, and were 0.5 μm, 1 μm, 5 μm, 15 μm, 30 μm, and 50 μm, respectively. Further, regarding the obtained porous elastomer particles A to F, the total content of the ionic liquid with respect to 1 g of the toner was calculated by the above-described method.

<Preparation of porous elastomer particles G to K>
Porous elastomer particles G to K were prepared as follows.
In the production of the porous elastomer particles D, the porous elastomer particles G to K were similarly prepared except that the total content of the ionic liquid with respect to 1 g of the toner was 0.05 mg, 0.1 mg, 5 mg, 30 mg, and 50 mg. Produced. When the number average particle diameter of the obtained porous elastomer particles G to K was measured by the method described above, all were 15 μm.

<Preparation of porous elastomer particles L to O>
Porous elastomer particles L to O were prepared as follows.
In the production of the porous elastomer particles D, the ionic liquids used for the impregnation treatment with the ionic liquid were respectively 1,3-diallylimidazolium bromide (0.5 mS / cm), N-butyl-N-methylpyrrolidinium. Other than bis (trifluoromethylsulfonyl) imide (1.0 mS / cm), 1-ethyl-3-methylimidazolium thiocyanate (20 mS / cm), 1-ethyl-3-methylimidazolium dicyanamide (30 mS / cm) Made porous elastomer particles L to O in the same manner. When the number average particle diameter of the obtained porous elastomer particles L to O was measured by the above-mentioned method, all were 15 μm. Further, regarding the obtained porous elastomer particles L to O, the total content of the ionic liquid with respect to 1 g of the toner was calculated by the above-described method.

  The number average particle diameter of the porous elastomer particles A to O, the total content of the ionic liquid with respect to 1 g of the toner of the porous elastomer particles A to O in the electrostatic image developer described later, and the electrical conductivity of the ionic liquid, The results are summarized in Table 1 below.

<External additive>
The external additives used in the examples are shown below.
External additive a: silica particles, number average particle diameter 80 nm
External additive b: silica particles, number average particle diameter 100 nm
External additive c: silica particles, number average particle diameter 150 nm
External additive d: silica particles, number average particle diameter 500 nm
External additive e: silica particles, number average particle diameter 600 nm

-Preparation of external additive a-
In a presence of 100 parts of ion-exchanged water and 100 parts of 25% alcohol, 150 parts of tetramethoxysilane was stirred at 250 rpm while 150 parts of 25% aqueous ammonia was added dropwise at 30 ° C. over 5 hours. The silica sol suspension obtained by this reaction is centrifuged, separated into wet silica gel, alcohol and aqueous ammonia, and the separated wet silica gel is dried at 120 ° C. for 2 hours, and then 100 parts of silica and 500 parts of ethanol are mixed. Was put into an evaporator and stirred for 15 minutes while maintaining the temperature at 40 ° C. Next, 10 parts of dimethyldimethoxysilane was added to 100 parts of silica, and the mixture was further stirred for 15 minutes. Finally, the temperature was raised to 90 ° C. and ethanol was dried under reduced pressure. The treated product was taken out and further vacuum dried at 120 ° C. for 30 minutes. The dried silica was pulverized to obtain an external additive a having a number average particle diameter of 80 nm.

-Preparation of external additive b-
In the preparation of external additive a, 25% ammonia water was added in the same manner as external additive a, except that 150 parts of aqueous ammonia was added dropwise over 4 hours and stirred at 200 rpm. An external additive b having a diameter of 100 nm was obtained.

-Preparation of external additive c-
In the preparation of the external additive a, the average particle size was determined by the same production method as that of the external additive a, except that 25% ammonia water was added at 150 rpm while dropping 150 parts of ammonia water over 4 hours. An external additive c having a diameter of 150 nm was obtained.

-Preparation of external additive d-
In the preparation of external additive a, 25% aqueous ammonia was added in the same manner as external additive a, except that 150 parts of aqueous ammonia was added dropwise over 1 hour and stirred at 80 rpm. An external additive d having a diameter of 500 nm was obtained.

-Preparation of external additive e-
In the preparation of external additive a, 25% aqueous ammonia was added in the same manner as external additive a, except that stirring was performed at 60 rpm while 150 parts of aqueous ammonia was added dropwise over 1 hour. An external additive e having a diameter of 600 nm was obtained.

<Preparation of toner base particles>
-Preparation of crystalline polyester resin dispersion-
In a heat-dried three-necked flask, 45 mol parts of 1,9-nonanediol, 55 mol parts of dodecanedicarboxylic acid and 0.05 mol parts of dibutyltin oxide as a catalyst were added, and the air in the container was reduced to nitrogen by depressurization. Under an inert atmosphere with gas, the mixture was stirred and refluxed at 180 ° C. for 2 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 5 hours. When it became viscous, it was air-cooled, the reaction was stopped, and a crystalline polyester resin was synthesized. It was 25,000 when the weight average molecular weight (Mw) of the obtained crystalline polyester resin was measured by the gel permeation chromatography (polystyrene conversion). Next, 3,000 parts of the obtained crystalline polyester resin, 10,000 parts of ion-exchanged water, and sodium dodecylbenzenesulfonate surfactant are added to an emulsification tank of a high-temperature / high-pressure emulsifier (Cabitron CD1010, slit: 0.4 mm). After 90 parts were added, the mixture was heated and melted to 130 ° C., dispersed at 110 ° C. at a flow rate of 3 L / m at 10,000 rotations for 30 minutes, passed through a cooling tank, and a crystalline polyester resin dispersion (high temperature / high pressure emulsification The apparatus (Cabitron CD1010, slit 0.4 mm, manufactured by Cavitron) was recovered to obtain a crystalline polyester resin dispersion.

-Preparation of amorphous polyester resin dispersion-
15 mol parts of polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane and 85 mol parts of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 10 mol parts of terephthalic acid, 67 mol parts of fumaric acid, 3 mol parts of n-dodecenyl succinic acid, 20 mol parts of trimellitic acid, and these acid components (terephthalic acid, n-dodecenyl succinic acid, trimellitic acid, 0.05 mol part of dibutyltin oxide is added to the total number of moles of fumaric acid), nitrogen gas is introduced into the container and the temperature is maintained in an inert atmosphere, and then heated at 150 to 230 ° C. The copolycondensation reaction was carried out for 20 hours. Thereafter, the pressure was gradually reduced at 210 ° C. to 250 ° C. to synthesize an amorphous polyester resin. The weight average molecular weight Mw of this resin was 65,000. Next, 3,000 parts of the obtained amorphous polyester resin, 10,000 parts of ion-exchanged water, and surfactant dodecylbenzenesulfonic acid were added to an emulsification tank of a high-temperature and high-pressure emulsifier (Cabitron CD1010, slit: 0.4 mm). After adding 90 parts of sodium, the mixture was heated and melted to 130 ° C., dispersed at 110 ° C. at a flow rate of 3 L / m for 30 minutes at 10,000 rpm, passed through a cooling tank, and an amorphous polyester resin dispersion (high-temperature A high-pressure emulsifier (Cavitron CD1010, slit 0.4 mm, manufactured by Cavitron) was recovered to obtain an amorphous polyester resin dispersion.

-Preparation of colorant dispersion-
-Cyan pigment (copper phthalocyanine B15: 3: manufactured by Dainichi Seika Kogyo Co., Ltd.): 1,000 parts-Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.): 150 parts-Ion-exchanged water: 4,000 parts The above compounded solution is mixed and dissolved, and dispersed for 1 hour with a high-pressure impact disperser Ultimizer (HJP30006, manufactured by Sugino Machine Co., Ltd.), and a colorant dispersion having a volume average particle size of 180 nm and a solid content of 20%. Got.

-Preparation of release agent dispersion-
Paraffin wax HNP9 (melting temperature 75 ° C .: manufactured by Nippon Seiki Co., Ltd.): 46 parts Cationic surfactant Neogen RK (produced by Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts Ion exchange water: 200 parts or more Is heated to 100 ° C. and sufficiently dispersed with IKA Ultra Turrax T50, and then dispersed with a pressure discharge type gorin homogenizer to obtain a release agent dispersion having a center diameter of 200 nm and a solid content of 20.0%. It was.

-Preparation of toner base particles-
Amorphous polyester resin dispersion: 256.8 parts Crystalline polyester resin dispersion: 33.2 parts Colorant dispersion: 27.4 parts Release agent dispersion: 35 parts The above is made of round stainless steel In the flask, the mixture was thoroughly mixed and dispersed with Ultra Turrax T50. Next, 0.20 part of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 60 minutes, 70.0 parts of the amorphous polyester resin dispersion was gradually added thereto. Thereafter, the pH of the system was adjusted to 8.0 with a 0.5 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing to stir using a magnetic seal for 3 hours. Retained. After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 1,000 parts of ion-exchanged water at 30 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate was 7.5 and the electric conductivity was 7.0 μS / cm, No. 2 was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper. Vacuum drying was then continued for 12 hours. The particle diameter at this time was measured by Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and the volume average particle diameter was 5.8 μm. In addition, the particle shape factor SF1 obtained by shape observation with Luzex was 129.

<Production of toner>
To 100 parts of the obtained toner base particles, 3.6 parts of the external additive shown in Table 2 was mixed with a Henschel mixer at 3,600 rpm for 10 minutes, and Examples 1 to 23 and Comparative Examples 1 to 4 were mixed. The toner used in 1 was obtained.

<Creation of carrier>
Ferrite particles (average particle size 50 μm, volume electrical resistance 3 × 10 ⁸ Ω · cm): 100 parts Toluene: 14 parts Perfluorooctylethyl acrylate / dimethylaminoethyl methacrylate copolymer (copolymerization ratio 90:10, Mw = 50,000): 1.6 parts Carbon black (VXC-72, manufactured by Cabot Corporation): 0.12 parts Among the above components, the components except for the ferrite particles are dispersed with a stirrer for 10 minutes to obtain a film-forming solution. Prepared, put this coating liquid and ferrite particles in a vacuum deaeration type kneader, and stirred for 30 minutes at 60 ° C., then reduced pressure to remove toluene, to form a resin film on the ferrite particle surface, A carrier was manufactured. The obtained carrier had a volume average particle size of 51 μm.

(Examples 1 to 23 and Comparative Examples 1 to 4)
<Production of developer>
The porous elastomer particles, the toner, and the carrier described in Table 1 prepared above were put in a V blender at a mass ratio of 0.05: 5: 95, respectively, and stirred for 20 minutes. Examples 1 to 23 and Developers of Comparative Examples 1 to 4 were obtained.
The obtained developer was filled in Docu Center Color 400 (manufactured by Fuji Xerox Co., Ltd.), and the following evaluations were performed.

<Evaluation>
The Docu Center Color400 manufactured by Fuji Xerox Co., Ltd., provided with the obtained electrostatic charge image developer, was allowed to stand for 1 day in a high-temperature and high-humidity environment (30 ° C. and 85% RH), and then an image with an area coverage of 1% was 100,000. Output continuously. Thereafter, using C2 paper manufactured by Fuji Xerox Co., Ltd., the image forming conditions were adjusted so that the image density was within the range of 1.0 to 1.5, and a 5 cm × 5 cm patch was output. The image density (density 1) of the obtained patch was measured by the method described later. Subsequently, 100,000 images with an area coverage of 20% were output continuously. Thereafter, using a C2 paper manufactured by Fuji Xerox Co., Ltd., a patch of 5 cm × 5 cm was output again under the same image forming conditions as when the patch having a density of 1 was formed, and the image density was measured (density 2).

[Evaluation of Image Density Variation (Δ Image Density (SAD: Sum of Absolute Difference) Evaluation)]
The value of Δ image density (SAD) represented by the following formula was calculated from the density 1 and density 2 and evaluated according to the following criteria. The image density was measured with an image densitometer X-RITE 938 (manufactured by X-RITE).
Expression: ΔImage density = | Density 1−Density 2 |
The evaluation criteria are as follows.
A: 0 <ΔImage density (SAD) ≦ 0.1
○: 0.1 <Δ image density (SAD) ≦ 0.2
×: 0.2 <Δ image density (SAD)

(Image defect evaluation)
For the continuous output of 100,000 images with the area coverage of 20% created as described above, the images are checked every 100 sheets (1,000 sheets in total), and the number of image defects (color streaks, color loss, etc.) has occurred. I counted.
◎: Number of image defects ≤ 1 ◯: 1 sheet <Number of image defects ≤ 10 △: 10 sheets <Number of image defects ≤ 30 x: 30 sheets <Number of image defects

  The evaluation results in each example and comparative example are summarized in Table 2.

In Examples 1 to 23, the image evaluation results obtained can suppress the occurrence of image defects even in a high temperature and high humidity environment (30 ° C. and 85% RH) as compared with Comparative Examples 1 to 4. It was found that an image with little fluctuation can be obtained.
In Examples 14 to 16 in which the total content of the ionic liquid in the electrostatic charge image developer is 0.1 mg to 30 mg with respect to 1 g of the toner, the total content of the ionic liquid is less than 0.1 mg with respect to 1 g of the toner. Or compared with Example 13 and 17 exceeding 30 mg, it turned out that generation | occurrence | production of an image defect can be suppressed more and an image with less density fluctuation | variation is obtained.
In Examples 19 to 20 in which the electric conductivity of the ionic liquid in the electrostatic image developer is 1.0 mS / cm or more and 20 mS / cm or less, the electric conductivity of the ionic liquid in the electrostatic image developer is 1. It was found that, compared with Examples 18 and 21, which are less than 0.0 mS / cm or more than 20 mS / cm, the occurrence of image defects can be further suppressed and an image with less density fluctuation can be obtained.
Examples 1 and 2 in which the number average particle diameter of the porous elastomer particles is 5 μm or more and 15 μm or less are poor in image quality compared to Examples 8 and 11 in which the number average particle diameter of the porous elastomer particles is less than 5 μm or more than 15 μm. It was found that generation can be further suppressed and an image with less density fluctuation can be obtained.

1Y, 1M, 1C, 1K, 107 Photoconductor 2Y, 2M, 2C, 2K, 108 Charging roller (charging device, charging means)
3Y, 3M, 3C, 3K Laser beam 3 Exposure device (exposure means)
4Y, 4M, 4C, 4K, 111 developing machine (developing means)
5Y, 5M, 5C, 5K Primary transfer roller (primary transfer means)
6Y, 6M, 6C, 6K, 113 Cleaning means 8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller (secondary transfer means )
28, 115 Fixing device (roll-type fixing means)
30 Cleaning means for intermediate transfer member 112 Transfer device 116 Mounting rail 117 Opening portion 118 for static elimination exposure Opening portion 200 for exposure Process cartridge P, 300 Recording paper (transferred material)

Claims (8)

A toner having toner base particles containing at least a binder resin, and an external additive having a number average particle diameter of 80 nm to 500 nm on the surface of the toner base particles;
Porous elastomer particles having a number average particle diameter of 1 μm or more and 30 μm or less,
The electrostatic image developer, wherein the porous elastomer particles contain an ionic liquid.   The electrostatic image developer according to claim 1, wherein a total content of the ionic liquid in the electrostatic image developer is 0.1 mg or more and 30 mg or less with respect to 1 g of the toner.   The electrostatic image developer according to claim 1 or 2, wherein the electric conductivity of the ionic liquid in the electrostatic image developer is 1.0 mS / cm or more and 20 mS / cm or less.   The electrostatic charge image developer of any one of Claims 1-3 whose number average particle diameter of the said porous elastomer particle is 5 micrometers or more and 15 micrometers or less.   A developer cartridge containing the electrostatic charge image developer according to claim 1.   5. A process cartridge comprising a developer holder that contains the electrostatic charge image developer according to claim 1 and that holds and conveys the electrostatic charge image developer. An image carrier,
Charging means for charging the image carrier;
Exposure means for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image;
Transfer means for transferring the toner image from the image carrier to the surface of the transfer target;
Fixing means for fixing the toner image transferred to the surface of the transfer target;
Cleaning means for cleaning the image carrier with a cleaning blade;
An image forming apparatus, wherein the developer is the electrostatic charge image developer according to claim 1. A latent image forming step for forming an electrostatic latent image on the surface of the image carrier;
A developing step of forming a toner image by developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner;
A transfer step of transferring the toner image onto the surface of the transfer target;
A fixing step of fixing the toner image transferred to the surface of the transfer target; and
A cleaning step of cleaning the developer remaining on the image carrier with a cleaning blade,
An image forming method using the electrostatic charge image developer according to claim 1 as the developer.

Images