JP2005265988A - Toner, developer, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner which allows to maintain high transfer efficiency, suppress a ghost, and give excellent image reproducibility even in the case of a system with low cleaning capability, and causes no adhesion to the members and a photoreceptor even in the case of the contact charging system, and to provide a developer and an image forming method. <P>SOLUTION: The toner contains at least binder resin, a coloring agent, and external additives, which are at least four kinds, i.e. an aluminum oxide particulate having a number average particle size of 5 to 50 nm, a titanium oxide particulate having a number average particle size of 5 to 50 nm, a silica particulate having a number average particle size, of 30 to 100 nm, and a resin particulate having a number average particle size of 50 to 300 nm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner, a developer, and an image forming method used for electrophotography, electrostatic recording, and the like in a copying machine, a printer, a facsimile, and the like.

  Conventionally, when an image is formed in a copying machine or a laser beam printer, the Carlson method is generally used. A conventional black-and-white electrophotographic image forming method develops an electrostatic latent image formed on a latent image carrier (photoreceptor) with toner, and transfers the obtained toner image onto a transfer medium. An image is obtained by fixing with a heat roll or the like. Further, since the latent image carrier again forms an electrostatic latent image, the remaining toner is removed.

  In recent years, the technology of electrophotography is rapidly expanding from black and white to full color. Color image formation by full-color electrophotography generally reproduces all colors using four colors obtained by adding black to the three primary colors yellow, magenta, and cyan. In a general full-color electrophotographic method, first, an original is color-separated into yellow, magenta, cyan, and black, and an electrostatic latent image is formed on the photoconductive layer for each color. Next, the toner that has undergone the development and transfer processes is held on a recording medium (transfer medium). Next, the above steps are sequentially performed a plurality of times, and the toner is superimposed on the same recording medium while aligning the positions. Then, a full color image is obtained by a single fixing process. The fact that several kinds of toners having different colors are superposed is a big difference between the black and white electrophotographic method and the full color electrophotographic method.

In a full-color image, an image is formed by superimposing three or four color toners, so that any of these toners has characteristics that are different from the initial characteristics in terms of development, transfer, and fixing, or performance that differs from other colors. , This causes image quality degradation such as color reproduction degradation, graininess degradation, and color unevenness.
Recently, high-quality quality is desired for full-color image quality. Therefore, since it is difficult to obtain a stable high image quality when such toner characteristic changes occur, it is more important to improve characteristics such as development, transfer, and fixing characteristics and to improve the stability of characteristics. .

  Furthermore, in recent years, from the viewpoint of environmental protection, the contact charging method and contact transfer using a contact member on the electrostatic latent image carrier from the conventionally used non-contact charging and non-contact transfer methods using corona discharge. Charging / transfer technology is shifting to methods. In the contact charging method and the contact transfer method, first, a conductive elastic roller is brought into contact with the electrostatic latent image carrier, and the electrostatic latent image carrier is uniformly charged while applying a voltage to the conductive elastic roller. Then, a toner image is obtained by an exposure and development process. Thereafter, the toner is transferred onto the intermediate transfer member while pressing the intermediate transfer member to which a voltage is applied to the electrostatic latent image carrier. Further, while pressing another conductive roller to which voltage is applied to the intermediate transfer member, a transfer medium such as paper is passed between them to transfer the toner image to the transfer medium, and then a transfer image is obtained through a fixing process. ing.

  In the case of the contact charging method, since the charging roller presses the photoconductor during charging, the transfer residual toner on the photoconductor passing through the cleaner and the free external additive adhere to the photoconductor and the charging roller, resulting in poor charging. An image defect may occur due to image flow or uneven charging of the attached portion.

In such a contact transfer system, the intermediate transfer member is brought into contact with the electrostatic latent image carrier during transfer. For this reason, when the toner image formed on the electrostatic latent image carrier is transferred to the intermediate transfer medium, the toner image is pressed against, causing partial transfer failure, and fogging toner and free external additives in the background. By pressing, it adheres to the photoreceptor or intermediate transfer member, and image quality defects may occur.
Further, as the diameter of the toner is reduced due to a demand for higher image quality in a color image, the adhesion force of the toner to the electrostatic latent image carrier becomes larger in transfer compared to the Coulomb force applied to the toner particles. As a result, there is a tendency that the transfer residual toner increases and the charging failure of the electrostatic latent image carrier is accelerated.

  For the purpose of preventing charging failure in the electrostatic latent image carrier, between the contact between the electrostatic latent image carrier and the intermediate transfer medium and the contact between the electrostatic latent image carrier and the conductive elastic roller. In addition, a cleaning means is provided. The residual toner is firmly fixed on the electrostatic latent image carrier as a result of the contact of the toner when passing between the electrostatic latent image carrier and the intermediate transfer member. As a cleaning method for removing the adhered residual toner from the electrostatic latent image carrier, a blade cleaning method in which the elastic blade is strongly pressed against the electrostatic latent image carrier and removed is suitable from the viewpoint of cleaning ability. It is considered and is generally used. However, in this system, not only the conductive elastic roller and the intermediate transfer member but also the elastic blade is strongly pressed against the electrostatic latent image carrier, so that wear due to surface deterioration of the electrostatic latent image carrier occurs. It was easy and there was a problem in life.

  On the other hand, a method of cleaning the electrostatic latent image carrier by pressing a brush against the electrostatic latent image carrier with a weak pressure instead of an elastic blade has been proposed. The cleaning method using a brush is effective in terms of suppressing surface deterioration of the electrostatic latent image carrier, but has a smaller toner capturing ability than an elastic blade. Further, when the transfer efficiency is low, there is a problem that the transfer afterimage passes through the brush cleaner and appears in the image as an afterimage.

If the process of transferring from the electrostatic latent image carrier to the intermediate transfer body is the primary transfer, and the process of transferring from the intermediate transfer body to the transfer medium is the secondary transfer, the transfer will be repeated twice, and the transfer efficiency improvement technology will increase more and more. Becomes important. In particular, in the case of secondary transfer, a multicolor image is transferred at once, and the transfer medium (for example, in the case of paper, its thickness, surface properties, etc.) changes variously. Must be controlled extremely high.
However, it has been confirmed that the transferability of the secondary transfer deteriorates due to changes in the fine structure of the toner surface, especially the embedding or peeling of the external additive, due to the influence of the stress applied during the primary transfer. Has been.

  In response to these problems, by externally adding fine particles selected from silica, alumina, and titania fine particles, and spherical resin fine particles having irregularities on the surface of 0.03 to 0.1 μm, the photosensitive member blade cleaner system can be bypassed. It has been proposed to prevent adhesion of toner to the charging member and the photoreceptor and to suppress image defects (see, for example, Patent Document 1), but in a system that does not use blade cleaning, transfer efficiency is poor. It is sufficient, and a ghost is generated due to a transfer residue, and a large amount of transfer residual toner stays on the photoconductor, and also adheres to the photoconductor.

  In addition, by externally adding fine particles selected from silica, alumina and titania fine particles of 1 to 30 nm and spherical resin fine particles of 70 to 900 nm, the transfer efficiency can be improved. An image forming method that collects transfer residual toner with a developing device has been proposed to suppress transfer ghost and transfer loss (see, for example, Patent Document 2). When the toner is developed and transferred, the transfer residue increases, ghosts and the like are not sufficiently suppressed, and a large amount of transfer residual toner stays on the photoconductor to cause fixation on the photoconductor.

Further, it has been proposed to maintain stable charging performance with toner containing three types of external additives of silica, alumina, and titania fine particles, and to prevent toner scattering by improving dischargeability from the toner cartridge (for example, Patent Documents). 3 and 4), transfer efficiency is not sufficient, waste toner increases when using a blade cleaner, and in a system that does not use blade cleaning, cleaning is insufficient and a transfer residual ghost is generated or a large amount of transfer residual is generated. Also, the toner stays on the photoconductor, so that the toner adheres to the photoconductor. Further, the toner charge distribution is widened, and image defects such as fog are likely to occur.
JP-A-8-268422 JP-A-9-288373 Japanese Patent Laid-Open No. 10-63032 Japanese Patent Laid-Open No. 11-15193

  From the above, it is an object of the present invention to solve the conventional problems and achieve the following objects. That is, an object of the present invention is to provide a toner, a developer, and an image forming method capable of maintaining high transfer efficiency and achieving ghost suppression even in a system having a low cleaning ability. In addition, the present invention provides a toner, a developer, and an image forming method capable of obtaining good image reproducibility by obtaining a stable charge over a long period of time with good environmental dependency of charging. Objective. Furthermore, even with the contact charging method, no toner adheres to the member or the photoconductor, the occurrence of scratches on the photoconductor is suppressed, no image defects occur, and the reproducibility of fine lines can be stabilized over a long period of time. An object of the present invention is to provide a toner, a developer, and an image forming method.

As a result of intensive studies to solve the above problems, the present inventors have found that the following problems can be solved by the present invention.
That is, the present invention is a toner containing at least a binder resin, a colorant and an external additive,
The external additive is aluminum oxide fine particles having a number average particle size of 5 to 50 nm, titanium oxide fine particles having a number average particle size of 5 to 50 nm, silica fine particles having a number average particle size of 30 to 100 nm, and number average particle size of 50. It is a toner characterized by at least four kinds of resin fine particles of ˜300 nm.

The toner of the present invention preferably includes at least one or more of the following first to fourth aspects.
(1) A 1st aspect is an aspect whose melting | fusing point of the said mold release agent is 70-100 degreeC.
(2) In the second aspect, the toner (toner base particles) excluding the external additive has a volume average particle diameter of 3 to 9 μm, and the average circularity of the toner base particles (simply referred to as “circularity”). Is) is 0.975 or more.
(3) In the third aspect, the toner of the present invention includes at least a resin particle dispersion having a resin particle dispersion diameter of 1 μm or less, a colorant dispersion having a colorant dispersion diameter of 0.5 μm or less, and a release agent dispersion diameter. Is mixed with a release agent dispersion having a particle size of 0.5 μm or less to form an aggregated particle dispersion of resin particles and a colorant, and then heated to a temperature equal to or higher than the endothermic peak temperature of the release agent to fuse and unite. It is the aspect manufactured by the manufacturing method including a process.
(4) A fourth aspect is an aspect in which the toner of the present invention is provided to an image forming apparatus provided with a means using at least one of a brush and a roll as a cleaning means.

  In addition, the present invention is a developer containing the toner of the present invention described above.

Furthermore, the present invention provides a latent image forming step of forming a latent image on a latent image carrier by performing a charging process, a developing step of developing the latent image using toner, and a developed image after development as a transfer medium An image forming method comprising: a transfer step of transferring to a latent image carrier; and a cleaning step of removing the toner after transfer remaining on the latent image carrier,
The toner is the toner of the present invention described above,
In the image forming method, the cleaning unit in the cleaning step is a unit using at least one of a brush and a roll.
In the image forming method of the present invention, the charging means for performing the charging treatment is preferably a contact charging means using a charging roller.

  According to the toner, developer, and image forming method of the present invention, high transfer efficiency can be maintained and ghost suppression can be achieved even in a system having a low cleaning ability. In addition, since the charging is highly dependent on the environment and stable charging can be obtained over a long period of time, it is possible to obtain good image reproducibility. Further, even with the contact charging method, the toner does not adhere to the member or the photosensitive member, the generation of scratches on the photosensitive member is suppressed, the image defect does not occur, and the reproducibility of the thin line can be stabilized over a long period of time. .

[1] Toner:
The toner of the present invention includes at least a binder resin, a colorant, and an external additive. In particular, as the external additive, at least the following four kinds of fine particles are used.
That is, the fine particles include aluminum oxide fine particles having a number average particle size of 5 to 50 nm; titanium oxide fine particles having a number average particle size of 5 to 50 nm; silica fine particles having a number average particle size of 30 to 100 nm; At least four kinds of resin fine particles of 50 to 300 nm.
Hereinafter, the present invention will be described in detail.

Due to the combined effect of the above four kinds of fine particles, filming of the photoreceptor and transfer residual ghost can be suppressed, the charging environment dependency of the toner can be improved, and an image free of fog and cloud can be stably output.
In particular, the effect is remarkable in a system having a low cleaning ability to which a blade cleaner is not applied. Further, even in a system in which filming due to pressing on a photosensitive member such as a charging roll as a charging unit is likely to occur, the effect can be remarkably exhibited.

  Here, “ghost” refers to a newly formed latent image when a toner image formed on a photoreceptor remains without being sufficiently transferred at the time of transfer, and forms a new latent image exposing the portion. A phenomenon in which a latent image corresponding to an afterimage of a previous toner image is formed in an image. When such a phenomenon occurs, an afterimage of a previously formed image is formed in a newly formed image, causing problems such as deterioration in image quality.

  Although the detailed mechanism of the composite effect of the four types of fine particles is unknown, the positively charged aluminum oxide fine particles interact with the negative silica fine particles for resin fine particles with a large particle size and high electrical resistance. Thus, the surface charge in the vicinity of the interface between the toner and the photoconductor, which has a high contribution to the electrostatic adhesion between the photoconductor and the toner, is locally neutralized. It is presumed that the effect of reducing the electrostatic adhesive force is exhibited by diffusing rapidly in the transfer electric field. The toner remaining on the surface of the photoconductor and the free external additive can be obtained due to the high transfer efficiency by reducing the adhesion force between the toner particles due to the relatively large diameter particles and the photoconductor and the combined effect of the four types of external additives. This may be due to the fact that it can be effectively scraped off by mutual charging or particle size difference between the four types of external additives.

  When the number average particle diameter of the aluminum oxide fine particles and titanium oxide fine particles is smaller than 5 nm, aggregates increase, image defects such as white spots, and free aggregates easily migrate to the photoconductor. Filming is likely to occur. On the other hand, if it exceeds 50 nm, the powder fluidity deteriorates and the toner supply tends to become unstable.

  When the number average particle diameter of silica fine particles is smaller than 30 nm, the fluidity imparting ability is increased, but the environmental dependency of charging is deteriorated, and particularly, charging under high temperature and high humidity is lowered and fogging is likely to occur. Become. When the thickness exceeds 100 nm, the toner is easily released from the toner, and the shift to the photoconductor increases due to the relationship between the charged columns and the photoconductor, and filming is likely to occur.

  When the number average particle diameter of the resin fine particles is smaller than 50 nm, aggregates increase, image defects such as white spots, and free aggregates easily migrate to the photoreceptor, and filming on the photoreceptor. It becomes easy to generate. If it exceeds 300 nm, the transfer efficiency is lowered and ghosts are generated or the toner is easily released from the toner, and filming on the photosensitive member is likely to occur.

  Examples of the resin fine particles include polystyrene fine particles, polymethyl methacrylate fine particles, polyvinylidene fluoride fine particles, and polyethylene fine particles. It is preferable to use at least one of these.

  The preferred number average particle diameter of the aluminum oxide fine particles is 10 to 40 nm. The preferred number average particle diameter of the titanium oxide fine particles is 10 to 40 nm. The preferred number average particle diameter of the silica fine particles is 40 to 80 nm. The preferred number average particle diameter of the resin fine particles is 80 to 200 nm.

  The number average particle diameter of the external additive is determined by, for example, externally adding the external additive alone to the toner to primarily disperse the external additive particles on the toner surface, and then scanning the toner surface with a scanning electron microscope (SEM). The major axis diameter and the number of external additives present on the toner surface are counted and averaged. Alternatively, the SEM image may be read by an image analysis device and the particle diameter of the external additive may be counted by binarization processing.

  The aluminum oxide fine particles, titanium oxide fine particles, and silica fine particles can be subjected to a hydrophobic treatment with a silane coupling agent or silicone oil. Since titanium oxide fine particles have a low charge of the particles themselves, it is preferable to increase the charge by such a surface hydrophobization treatment. Silica fine particles are also preferably subjected to such surface hydrophobization treatment for the purpose of suppressing the environmental dependence of charging.

  The addition amount of the aluminum oxide fine particles is preferably in the range of 0.1 to 1.0 part by mass, more preferably in the range of 0.2 to 0.6 part by mass with respect to 100 parts by mass of the toner base particles. . The addition amount of the titanium oxide fine particles is preferably in the range of 0.3 to 1.5 parts by mass, more preferably in the range of 0.5 to 1.0 parts by mass with respect to 100 parts by mass of the toner base particles. . The addition amount of the silica fine particles is preferably in the range of 0.5 to 2.5 parts by mass, more preferably in the range of 1.0 to 2.0 parts by mass with respect to 100 parts by mass of the toner base particles. The amount of resin fine particles added is preferably in the range of 0.5 to 2.5 parts by mass, more preferably in the range of 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the toner base particles.

  In addition to these four types of external additives, an abrasive such as cerium oxide may be included for the purpose of always refreshing the surface of the photoreceptor. Further, an external additive transferred to the surface of the photoreceptor and an external additive such as a solid lubricant such as zinc stearate and molybdenum disulfide for smoothly scraping off the toner can be used in combination.

  The toner of the present invention comprises toner base particles containing a binder resin, a colorant, a release agent and the like, and the external additive described above. The toner base particles are prepared by a melt-kneading pulverization method. Particles prepared by suspension polymerization, dissolution suspension, emulsion polymerization aggregation, etc. can be used. The volume average particle diameter of the toner base particles is preferably 3 to 9 μm, and more preferably 5 to 8 μm, from the viewpoint of the image quality of the output image and suitability for the electrophotographic system.

It is preferable to use a Coulter Counter TA-II type (manufactured by Beckman-Coulter) as an apparatus for measuring the volume average particle diameter of the toner base particles, and use ISOTON-II (manufactured by Beckman-Coulter) as the electrolyte.
As a measurement method, 0.5 to 50 mg of a measurement sample (toner mother particles) is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This is added to 100 to 150 ml of the electrolytic solution.

  The electrolyte 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 distribution of particles of 2.0 to 60 μm is obtained using the Coulter counter TA-II type with an aperture diameter of 100 μm. Measure volume average distribution and number average distribution. The number of particles to be measured is 50,000. From these volume average distribution and number average distribution, the weight average particle diameter is obtained. In the particle size distribution, for the divided particle size range (channel), the cumulative distribution is drawn from the small diameter side to the volume and the number, respectively, and the particle size that becomes 50% cumulative is defined as the volume average particle size D50v and the number average particle size D50p. The volume average diameter (also referred to as cumulative volume average particle diameter D50) D50v is referred to as the volume average particle diameter (D50 diameter).

From the viewpoint of transfer efficiency, the average circularity of the toner base particles is preferably 0.975 or more, and more preferably 0.975 to 0.99.
The average circularity is obtained, for example, by taking an optical microscopic image of toner base particles dispersed on a slide glass into a Luzex image analyzer through a video camera, and (4 × π × projection area) / (perimeter length) of 50 or more toners. ² ] and an average value can be obtained.
The same measurement of the average circularity can be performed using a flow particle image analyzer: FPIA-2100 (manufactured by Simex Co., Ltd.).

In particular, as a method for producing toner base particles, an emulsion polymerization aggregation method is preferable for controlling the particle shape and particle diameter.
The toner of the present invention is prepared by mixing at least the four types of external additives described above with toner base particles prepared by applying the emulsion polymerization aggregation method.
Specifically, first, the following resin particle dispersion, colorant dispersion, and release agent dispersion were respectively prepared, mixed at a predetermined ratio and stirred, and a polymer of an inorganic metal salt was added thereto. Add and ionically neutralize to form agglomerated particles. The pH of the system is adjusted from weakly acidic to neutral with an inorganic hydroxide, and then heated to a temperature higher than the glass transition temperature of the resin particles to raise the temperature to the fusion and coalescence temperature. After reaching the fusion / unification temperature, the pH in the system is adjusted from weakly acidic to acidic and heating is continued. After the completion of the reaction, the desired toner base particles are obtained through sufficient washing, solid-liquid separation, and drying steps, and at least 5 to 50 nm aluminum oxide fine particles, 5 to 50 nm titanium oxide fine particles, and 30 to 100 nm silica. The toner of the present invention can be obtained by externally adding four types of fine particles and 50 nm to 300 nm resin fine particles.

  The method of externally adding the four types of external additives is not particularly limited, and for example, external additives can be added by mixing using a Henschel mixer or the like. The toner of the present invention is preferably used in an image forming apparatus provided with a means using at least one of a brush and a roll as a cleaning means.

The resin particle diameter of the resin particle dispersion used in the emulsion polymerization aggregation method is preferably 1 μm or less in order to improve the internal dispersibility of the colorant and release agent. More preferably, it is 0.5 μm or less.
The colorant dispersion diameter of the colorant dispersion is preferably 0.5 μm or less from the viewpoint of color development and OHP permeability. More preferably, it is 0.3 μm or less. Moreover, 0.05 micrometer or more is preferable from the point which produces an aggregated particle efficiently.
The release agent dispersion diameter of the release agent dispersion is preferably 0.5 μm or less from the viewpoint of color development and OHP permeability. More preferably, it is 0.3 μm or less. On the other hand, 0.05 μm or more is preferable from the viewpoint of efficiently producing aggregated particles.

  After the resin particle dispersion, colorant dispersion, and release agent dispersion are mixed to form aggregated particles, the surface of the toner particles can be coated with the resin particles by adding the resin particle dispersion. This method is preferable in that the colorant concentration and the release agent concentration on the surface can be kept low.

In order to obtain an appropriate release agent domain structure so that the particles are sufficiently fused after the agglomerated particles are formed and the release agent is easily oozed out inside the particles, the release agent endothermic peak temperature of the toner base particles is used. It is preferable to heat and fuse them as described above. More preferably, the fusion is performed at a temperature higher by 10 ° C. or more than the endothermic peak temperature of the release agent.
Examples of the resin particles (binder resin) used in the resin particle dispersion include thermoplastic binder resins, and specifically, styrene such as styrene, parachlorostyrene, and α-methylstyrene. Homopolymers or copolymers (styrene resins); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, methacrylic acid Homopolymers or copolymers of vinyl groups such as ethyl acetate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc .; vinyl nitriles such as acrylonitrile and methacrylonitrile Homopolymer or copolymer (vinyl resin); vinyl methyl ether, vinyl Homopolymers or copolymers of vinyl ethers such as ruisobutyl ether (vinyl resins); Homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl resins) ; Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, and isoprene (olefin-based resins); Non-vinyl condensation systems such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins And a graft polymer of these non-vinyl condensation resins and vinyl monomers. These resins may be used alone or in combination of two or more.

  Among these resins, styrene resins, vinyl resins, polyester resins, and olefin resins are preferable. Copolymers of styrene and n-butyl acrylate, n-butyl acrylate, bisphenol A / fumaric acid copolymer. A copolymer of styrene and olefin is particularly preferred from the viewpoint of the stability of the dispersion.

  When a vinyl monomer is used as the binder resin component, an ionic surfactant or the like can be used to carry out emulsion polymerization to produce a resin particle dispersion, and when other resins are used. If it is oily and dissolves in a solvent with a relatively low solubility in water, the resin is dissolved in those solvents, and the particles are submerged in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte in water. Then, the resin particle dispersion can be prepared by evaporating the solvent by heating or decompression. The resin particle diameter (center particle diameter) of the obtained resin particle dispersion is measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

The colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner.
For example, examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.
Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa yellow, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, and permanent yellow NCG.
Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, benzidine orange G, indanthrene brilliant orange RK, indanthrene brilliant orange GK and the like.

Red pigments include Bengala, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B rake, lake red C , Rose bengal, oxin red, alizarin lake and the like.
Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, indanthrene blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate and so on.

Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake. Examples of the green pigment include chromium oxide, chromium green, pigment green, malachite green lake, final yellow green G, and the like.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.
Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white. Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

  And these can be used individually or in mixture, and also in the state of a solid solution. These colorants are dispersed in water by known methods together with ionic surfactants and polymer electrolytes such as polymer acids and polymer bases in water. For example, rotary shear type homogenizers, ball mills, sand mills, etc. A media type dispersing machine such as an attritor, a high-pressure opposed collision type dispersing machine, or the like is preferably used. Moreover, the particle diameter (center particle diameter) of the obtained colorant particle dispersion is measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

  The content of the colorant in the toner of the present invention is suitably in the range of 1 to 20 parts by mass in terms of solid content with respect to 100 parts by mass of the binder resin. When a magnetic material is used for the black colorant, it is preferably contained in the range of 30 to 100 parts by mass, unlike other colorants.

When the toner is used as a magnetic toner, magnetic powder may be included. As such magnetic powder, a substance magnetized in a magnetic field is used, and ferromagnetic powder such as iron, cobalt, nickel, or a compound such as ferrite, magnetite, or the like is used.
When the toner is produced in the aqueous phase, it is necessary to pay attention to the transferability of the magnetic material to the aqueous phase, and it is preferable to modify the surface of the magnetic material by subjecting it to a hydrophobic treatment or the like.

The release agent (wax) dispersion is dispersed in water together with an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base by a known method, and then a homogenizer or a pressure discharge type disperser is used. Then, it is made into fine particles by applying strong shearing while heating above the melting point, and a dispersion of fine particles of 1 μm or less can be prepared.
The particle size (center particle size) of the obtained release agent particle dispersion is measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

The mold release agent to be used is preferably a material having a melting point of 70 to 100 ° C. When the melting point is 70 to 100 ° C., it is possible to show a preferable release of the release agent with respect to the melt viscosity of the binder resin, so that it is possible to improve the fixing characteristics, particularly hot offset resistance.
Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene, silicones having a softening point by heating, oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide and the like. Fatty acid amides, carnauba wax, rice wax, candelilla wax, plant waxes such as tree wax, jojoba oil, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Minerals such as Fischer-Tropsch wax, petroleum-based waxes, and modified products thereof can be used.
The content of the release agent is preferably 3 to 20 parts by mass and more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the binder resin.

In the toner of the present invention, a charge control agent can be used in order to further improve and stabilize the chargeability.
As the charge control agent, commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments can be used. In view of controlling the ionic strength that affects the stability of the mixture and temporary contamination and reducing wastewater contamination, a material that is difficult to dissolve in water is preferable.

  In the present invention, inorganic fine particles can be added by a wet method in order to stabilize the charging property. Examples of inorganic fine particles to be added include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, which are usually used by adding them externally to the toner surface. It can be used dispersed in a molecular base.

  In the toner production method of the present invention, examples of the surfactant used for emulsion polymerization, colorant dispersion, resin particle dispersion, release agent dispersion, aggregation, or stabilization thereof include, for example, sulfate ester salts and sulfonate salts. Anionic surfactants such as phosphates and soaps, cationic surfactants such as amine salts and quaternary ammonium salts, polyethylene glycols, alkylphenol ethylene oxide adducts, polyhydric alcohols It is also effective to use a nonionic surfactant or the like together. As the dispersing means, a rotary shear type homogenizer, a ball mill having a media, a sand mill, a dyno mill, or the like can be used.

  When using a composite consisting of resin particles and a colorant, the resin and the colorant are dissolved and dispersed in a solvent, then dispersed in water together with the appropriate dispersant, and the solvent is removed by heating and decompression. It can be prepared and prepared by a method of obtaining, a method of applying to a resin particle surface prepared by emulsion polymerization with a mechanical shear force, or a method of electrically adsorbing and fixing. These methods are effective in suppressing the liberation of the colorant as additional particles and improving the dependency of the chargeable colorant.

  After completion of the polymerization, a desired toner is obtained through any washing step, solid-liquid separation step, and drying step. In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration and the like are preferable from the viewpoint of productivity. The drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

[2] Developer:
The developer (electrostatic latent image developer) of the present invention contains the toner of the present invention described above, and there is no particular limitation other than that, and an appropriate component composition can be taken according to the purpose. The developer of the present invention becomes a one-component electrostatic latent image developer when the toner of the present invention is used alone, and becomes a two-component electrostatic latent image developer when used in combination with a carrier. Here, since the developer of the present invention is expected to have an effect of locally neutralizing the surface charge of the toner, it is preferable that the charge amount (tribo) of the toner viewed macroscopically is high. Therefore, it is preferable to use a two-component electrostatic latent image developer in order to sufficiently exhibit the effect of controlling the toner charge amount to a high level.

  For example, when a carrier is used, the carrier is not particularly limited, and examples thereof include known carriers. Examples thereof include known carriers such as resin-coated carriers described in JP-A Nos. 62-39879 and 56-11461.

  Specific examples of the carrier include the following resin-coated carriers. Examples of the carrier core particles include normal iron powder, ferrite, and magnetite molding, and the average particle diameter is in the range of about 30 to 200 μm. The average particle diameter can be measured with a Coulter counter after being dispersed in water together with a surfactant, as in the case of toner base particles.

  Examples of the coating resin of the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, and 2-ethylhexyl acrylate. Α-methylene fatty acid monocarboxylic acids such as methyl methacrylate, n-propyl methacrylate, lauryl methacrylate and 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone Homopolymers such as vinyl ketones such as ethylene; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers comprising two or more types of monomers, Furthermore, silicone resins including methylsilicone, methylphenylsilicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned.

These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by mass, more preferably in the range of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the core particles.
For the production of the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. .
The mixing ratio of the toner of the present invention and the carrier in the developer is not particularly limited and can be appropriately selected depending on the purpose.

  Since the toner of the present invention described above is contained, the developer of the present invention can maintain high transfer efficiency and achieve ghost suppression even in a system having a low cleaning ability. In addition, since the charging is highly dependent on the environment and stable charging can be obtained over a long period of time, it is possible to obtain good image reproducibility. Further, even with the contact charging method, the toner does not adhere to the member or the photosensitive member, the generation of scratches on the photosensitive member is suppressed, the image defect does not occur, and the reproducibility of the thin line can be stabilized over a long period of time. .

[2] Image forming method:
The image forming method of the present invention comprises a latent image forming step of forming a latent image on a latent image carrier by performing a charging process, a developing step of developing the latent image using toner, and a developed image after development. An image forming method comprising: a transfer step of transferring to a transfer medium; and a cleaning step of removing the toner after transfer remaining on the latent image carrier, wherein the toner is the toner according to claim 1. The cleaning means in the cleaning step is a means using at least one of a brush and a roll.
Since the image forming method of the present invention uses the toner of the present invention described above, the above-described effects can be exhibited well. Hereinafter, each process is explained in full detail.
The same effect can be obtained by using the developer for developing an electrostatic charge image of the present invention instead of the toner. In addition, a known process such as a fixing process is appropriately added.

  The latent image forming step is a step of forming an electrostatic latent image by uniformly charging the surface of the latent image carrier with a charging means and then exposing the latent image carrier with a laser optical system or an LED array. is there. Examples of the charging means include a non-contact charger such as corotron and scorotron, and a contact method in which a latent image carrier surface is charged by applying a voltage to a conductive member in contact with the latent image carrier surface. Any type of charger may be used. However, a contact charging type charger is preferable from the viewpoint that the amount of ozone generated is small, environmentally friendly, and excellent printing durability. In the contact charging type charger, the shape of the conductive member may be any of a brush shape, a blade shape, a pin electrode shape, a roller shape, and the like, but a roller-like member is preferable.

  The developing step refers to the electrostatic latent image on the surface of the latent image carrier by bringing the developer carrier on which the developer layer containing at least the toner of the present invention is formed on the surface of the latent image carrier. In this step, toner particles are adhered to the surface of the latent image carrier to form a toner image (development image). The development method can be performed using a known method, but examples of the development method using a two-component developer include a cascade method and a magnetic brush method.

The transfer process is a process in which the toner image formed on the surface of the latent image carrier is directly transferred to the transfer medium, or the image once transferred to the intermediate transfer body is transferred again to the transfer medium to form a transfer image.
A corotron can be used as a transfer device for transferring the toner image from the latent image carrier to paper or the like. The corotron is effective as a means for uniformly charging the paper, but in order to give a predetermined charge to the paper as a transfer medium, a high voltage of several kV must be applied and a high voltage power source is required. Further, since ozone is generated by corona discharge, the rubber parts and the latent image carrier are deteriorated. Therefore, a conductive transfer roll made of an elastic material is pressed against the latent image carrier to transfer the toner image onto the paper. A contact transfer method is preferred.

The cleaning process is a process in which a blade, brush, roll, or the like is brought into direct contact with the surface of the latent image carrier to remove toner, paper dust, dust, etc. adhering to the surface of the latent image carrier.
The cleaning means in the image forming method of the present invention is a means using at least one of a brush and a roll. Although the cleaning means has a low cleaning capability, since the toner of the present invention described above is used, high transfer efficiency can be maintained and ghost suppression can be achieved. Further, it is possible to suppress the occurrence of scratches on members such as a photoreceptor, no image defects, and the reproducibility of fine lines can be stabilized over a long period of time.

  The fixing step is a step of fixing the developed image (toner image) transferred on the transfer medium surface by a fixing device. As the fixing device, an oilless heat fixing device using a heat roll is preferably used. The heat fixing device includes a fixing roller having a heater lamp for heating inside a cylindrical metal core, a so-called release layer formed on the outer peripheral surface by a heat resistant resin film layer or a heat resistant rubber film layer, and the fixing roller. The pressure roller or pressure belt is disposed in pressure contact with the roller and has a heat-resistant elastic layer formed on the outer peripheral surface of the cylindrical metal core or the surface of the belt-like base material. The fixing process of an unfixed toner image is performed by inserting a transfer medium on which an unfixed toner image is formed between a fixing roller and a pressure roller or a pressure belt, so that a binder resin, an additive, etc. Fix by heat melting.

  In the image forming method of the present invention, when producing a full-color image, each of the plurality of latent image carriers has a developer carrier of each color, and the plurality of latent image carriers and developer carriers. Each color toner image is sequentially laminated on the same transfer medium surface by a series of processes consisting of a latent image forming process, a developing process, a transferring process, and a cleaning process, and the stacked full-color toner images. An image forming method is preferably used in which the toner is thermally fixed in the fixing step. By using the toner or developer in the image forming method, stable development, transfer, and fixing performance can be obtained even in a tandem system suitable for, for example, miniaturization and high-speed color.

  Examples of the transfer medium for transferring the toner image include plain paper, an OHP sheet, and the like used in electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, the surface of the transfer medium is preferably as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these at all.

(Preparation of resin particle dispersion 1)
"Styrene" ... 300 parts by weight "n-butyl acrylate" ... 100 parts by weight "acrylic acid" ... 6 parts by weight "dodecanethiol" ... 20 parts by weight "carbon tetrabromide" ... 4 parts by mass

  The above components were mixed and dissolved. On the other hand, 6 g of nonionic surfactant Nonipol 400 (manufactured by Sanyo Kasei Co., Ltd.) and 10 g of anionic surfactant Neogen SC (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 500 g of ion-exchanged water. The product was placed in a flask, the above mixed solution was added, dispersed and emulsified, and 50 g of an ion exchange solution in which 4 g of ammonium persulfate was dissolved was added while slowly stirring and mixing for 10 minutes. Next, after sufficiently replacing the inside of the system with nitrogen, the flask was heated with an oil bath to 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours. As a result, an anionic resin particle dispersion 1 having a resin particle central particle size of 210 nm, a glass transition point of 53 ° C., and a weight average molecular weight of Mw 32000 was obtained.

(Preparation of resin particle dispersion 2)
"Styrene" ... 330 parts by mass "n-butyl acrylate" ... 70 parts by mass "acrylic acid" ... 6 parts by mass "dodecanethiol" ... 20 parts by mass "carbon tetrabromide" ... 4 parts by mass

  The above components were mixed and dissolved. On the other hand, 6 g of nonionic surfactant Nonipol 400 (manufactured by Sanyo Kasei Co., Ltd.) and 10 g of anionic surfactant Neogen SC (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 500 g of ion-exchanged water. The product was placed in a flask, the above mixed solution was added, dispersed and emulsified, and 50 g of an ion exchange solution in which 4 g of ammonium persulfate was dissolved was added while slowly stirring and mixing for 10 minutes. Next, after sufficiently replacing the inside of the system with nitrogen, the flask was heated with an oil bath to 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours. As a result, an anionic resin particle dispersion 2 having a resin particle central diameter of 240 nm, a glass transition point of 50 ° C., and a weight average molecular weight Mw of 38500 was obtained.

(Preparation of resin particle dispersion 3)
"Styrene" ... 370 parts by mass "n-butyl acrylate" ... 30 parts by mass "acrylic acid" ... 8 parts by mass "dodecanethiol" ... 30 parts by mass "carbon tetrabromide" ... 4 parts by mass

  The above components were mixed and dissolved. On the other hand, 6 g of nonionic surfactant Nonipol 400 (manufactured by Sanyo Kasei Co., Ltd.) and 10 g of anionic surfactant Neogen SC (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 500 g of ion-exchanged water. The product was placed in a flask, the above mixed solution was added, dispersed and emulsified, and 50 g of an ion exchange solution in which 4 g of ammonium persulfate was dissolved was added while slowly stirring and mixing for 10 minutes. Next, after sufficiently replacing the inside of the system with nitrogen, the flask was heated with an oil bath to 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours. Thus, an anionic resin particle dispersion 3 having a resin particle central diameter of 180 nm, a glass transition point of 60 ° C., and a weight average molecular weight Mw of 19000 was obtained.

(Preparation of Colorant Dispersion 1 (Cyan))
“Cyan pigment (manufactured by Dainichi Seika Co., Ltd., copper phthalocyanine B15: 3)” 50 parts by mass “Nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd., Nonipol 400)” 5 parts by mass “ion-exchanged water” 200 parts by mass

  The above components were mixed and dissolved, and dispersed for 10 minutes with a homogenizer (manufactured by IKA, Ultra Turrax: T50) to obtain a colorant dispersion 1 containing colorant particles having a center particle diameter of 168 nm.

(Preparation of Colorant Dispersion 2 (Yellow))
A colorant dispersion 2 containing colorant particles having a center particle diameter of 177 nm was prepared in the same manner as in the preparation of colorant dispersion 1, except that the same amount of yellow pigment (PY180, manufactured by Clariant Japan Co., Ltd.) was used as the colorant. Obtained.

(Preparation of Colorant Dispersion 3 (Magenta))
A colorant dispersion containing colorant particles having a center particle diameter of 186 nm, in the same manner as in the preparation of colorant dispersion 1, except that the same amount of magenta pigment (manufactured by Dainichi Ink Chemical Co., Ltd., PR122) was used as the colorant. 3 was obtained.

(Preparation of Colorant Dispersion 4 (Black))
A colorant dispersion 4 containing colorant particles having a center particle diameter of 159 nm was prepared in the same manner as in the preparation of the colorant dispersion 1, except that the same amount of black pigment (carbon black, manufactured by Cabot) was used as the colorant. Obtained.

(Preparation of release agent dispersion 1)
“Paraffin wax (Nippon Seiwa Co., Ltd., HNP09, melting point 77 ° C.)” 50 parts by mass “Cationic surfactant (manufactured by Kao Corporation, Sanizol B50)” 5 parts by mass “ion-exchanged water” ..200 parts by mass

  The above components are heated to 95 ° C. and sufficiently dispersed with IKA's Ultra Turrax T50, then subjected to dispersion treatment with a pressure discharge type homogenizer, and release agent dispersion containing release agent particles having a central particle size of 160 nm. Liquid 1 was obtained.

(Preparation of release agent dispersion 2)
“Polyethylene wax (Toyo Petrolite, polywax 1000, melting point 113 ° C.)” 50 parts by mass “Cationic surfactant (manufactured by Kao Corporation, SANISOL B50)” 5 parts by mass “ion exchange water” ... 200 parts by mass

  The above components are heated to 95 ° C. and sufficiently dispersed with IKA's Ultra Turrax T50, then subjected to dispersion treatment with a pressure discharge type homogenizer, and release agent dispersion containing release agent particles having a central particle size of 220 nm. Liquid 2 was obtained.

(Production of toner mother particles (Yellow) 1)
"Resin particle dispersion 1" ... 200 parts by weight "Colorant dispersion 2" ... 28 parts by weight "Releasing agent dispersion 1" ... 37 parts by weight "Polyaluminum chloride" ... 1. 23 parts by mass

The above components were thoroughly mixed and dispersed in a round stainless steel flask with a homogenizer (manufactured by IKE, Ultra Turrax T50), and then heated to an aggregation temperature of 50 ° C. while stirring the flask in an oil bath for heating. Then, after hold | maintaining at 50 degreeC for 60 minute (s), 30 mass parts of resin particle dispersion liquid 1 was further added, and it stirred gently. Thereafter, the pH of the system was adjusted to 7.0 with a 0.5 mol / liter sodium hydroxide aqueous solution, and then the stainless steel flask was sealed and heated to 90 ° C. while stirring was continued using a magnetic seal. Thereafter, the pH was lowered to 3.8 and held for 6 hours. 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. Furthermore, it was dispersed again in 3 liters of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. After this washing operation was repeated 5 times, solid-liquid separation was performed by Nutsche suction filtration using No5A filter paper. Next, vacuum drying was continued for 12 hours to obtain yellow toner base particles 1.
When the particle size of the toner base particles 1 was measured with a Coulter counter, the cumulative volume average particle size D50 was 5.8 μm. Furthermore, the circularity of the particle | grains calculated | required from the shape observation by FPIA was 0.984, and was spherical. The endothermic peak temperature measured by DSC was 76.5 ° C.

(Production of toner mother particle (Magenta) 2)
In the production of the toner base particles 1, the addition amount of the release agent dispersion 1 is 8.0% by weight in terms of solids, and the addition amount is 7.5% by weight in terms of solids by using the magenta colorant dispersion 3. The toner base particles 2 were changed in the same manner as in the production of the toner base particles 1 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 4.1 and the fusing and coalescence time was 5 hours. Obtained.
When the particle size of the toner base particles 2 was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.2 μm.
Furthermore, the circularity of the particle | grains calculated | required by shape observation by FPIA was 0.982, and was spherical. The endothermic peak temperature measured by DSC was 76.3 ° C.

(Production of toner mother particle (Cyan) 3)
In the production of toner base particles 1, the amount of release agent dispersion 1 added was changed to 9.0% by weight in terms of solid content, and the amount of colorant dispersion 1 added was changed to 5.0% by weight in terms of solid content, Toner base particles 3 were obtained in the same manner as in the manufacture of toner base particles 1 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 4.0.
When the particle size of the toner base particles 3 was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.0 μm. Furthermore, the circularity of the particle | grains calculated | required by shape observation by FPIA was 0.986, and was spherical. The endothermic peak temperature measured by DSC was 76.3 ° C.

(Manufacture of toner mother particle (Black) 4)
In the production of the toner base particles 1, the addition amount of the release agent dispersion 1 is changed to 7.0% by weight in terms of solid content, and the addition amount of the colorant dispersion 4 is changed to 5.0% by weight in terms of solid content, Toner base particles 4 were obtained in the same manner as in the production of the toner 1 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 4.0.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.0 μm. Furthermore, the circularity of the particle | grains calculated | required from the shape observation by FPIA was 0.985, and was spherical. The endothermic peak temperature measured by DSC was 76.3 ° C.

(Production of toner mother particles (Yellow) 5)
"Resin particle dispersion 2" ... 200 parts by weight "Colorant dispersion 2" ... 28 parts by weight "Releasing agent dispersion 1" ... 42 parts by weight "polyaluminum chloride" ... 1. 23 parts by mass

With the above components, yellow toner base particles 5 were obtained in the same manner as in the manufacture of toner base particles 1.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.3 μm. Furthermore, the circularity of the particle | grains calculated | required by shape observation by FPIA was 0.982, and was spherical. The endothermic peak temperature measured by DSC was 76.1 ° C.

(Production of toner mother particle (Magenta) 6)
In the production of the toner base particles 5, the addition amount of the release agent dispersion 1 is 9.0% by weight in terms of solids, and the addition amount is 7.5% by weight in terms of solids by using the magenta colorant dispersion 3. The toner base particles 6 were changed in the same manner as in the production of the toner base particles 5 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 4.1 and the fusion and coalescence time was 5 hours. Obtained.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.6 μm. Furthermore, the circularity of the particle | grains calculated | required from the shape observation by FPIA was 0.981, and was spherical. The endothermic peak temperature measured by DSC was 77.1 ° C.

(Production of toner mother particle (Cyan) 7)
In the production of the toner base particles 5, the addition amount of the release agent dispersion 1 is changed to 10.0% by weight in terms of solids, and the addition amount of the colorant dispersion 1 is changed to 5.0% by weight in terms of solids. Toner base particles 7 were obtained in the same manner as in the manufacture of toner base particles 5 except that the system pH when reaching 90 ° C. after the stop of aggregation was 4.0.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.4 μm. Furthermore, the circularity of the particle | grains calculated | required from the shape observation by FPIA was 0.984, and was spherical. The endothermic peak temperature measured by DSC was 77.2 ° C.

(Manufacture of toner mother particle (Black) 8)
In the production of the toner base particles 5, the addition amount of the release agent dispersion 1 is changed to 9.0% by weight in terms of solid content, and the addition amount of the colorant dispersion 4 is changed to 5.0% by weight in terms of solid content. Toner base particles 8 were obtained in the same manner as in the production of toner base particles 5 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 4.0.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 6.7 μm. Furthermore, the circularity of the particle | grains calculated | required by shape observation by FPIA was 0.982, and was spherical. The endothermic peak temperature measured by DSC was 76.8 ° C.

(Production of toner mother particles (Yellow) 9)
"Resin particle dispersion 3" ... 200 parts by weight "Colorant dispersion 2" ... 28 parts by weight "Releasing agent dispersion 2" ... 85 parts by weight "Polyaluminum chloride" ... 1. 5 parts by mass

  The above components were thoroughly mixed and dispersed in a round stainless steel flask with a homogenizer (manufactured by IKE, Ultra Tarrax T50), and then heated to an aggregation temperature of 54 ° C. while stirring the flask in a heating oil bath. Then, after maintaining at 54 ° C. for 60 minutes, 30 parts by mass of the resin particle dispersion 1 was further added and gently stirred. Thereafter, the pH of the system was adjusted to 7.0 with a 0.5 mol / liter sodium hydroxide aqueous solution, and then the stainless steel flask was sealed and heated to 90 ° C. while stirring was continued using a magnetic seal. Thereafter, the pH was lowered to 6.0 and held for 2 hours. 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. Further, it was dispersed again in 3 L of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. After repeating this washing operation 5 times, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. Next, vacuum drying was continued for 12 hours to obtain yellow toner mother particles 9.

  When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 9.6 μm. Furthermore, the circularity of the particles determined by shape observation with FPIA was 0.970. The endothermic peak temperature measured by DSC was 112.1 ° C.

(Production of toner base particle (Magenta) 10)
In the production of the toner mother particles 9, the addition amount of the release agent dispersion 2 is changed to 18% by weight in terms of solids, and the addition amount is changed to 7.5% by weight in terms of solids by using the magenta colorant dispersion 3. The toner 10 was obtained in the same manner as in the production of the toner mother particles 9 except that the system pH when the temperature reached 90 ° C. after the stop of aggregation was 6.2, and the fusion and coalescence time was 2 hours.
When the particle size of the toner base particles was measured with a Coulter counter, the cumulative volume average particle size D50 was 9.3 μm. Furthermore, the circularity of the particles determined by shape observation with FPIA was 0.968. The endothermic peak temperature measured by DSC was 112.9 ° C.

(Production of toner mother particle (Cyan) 11)
In the production of the toner mother particles 9, the addition amount of the release agent dispersion liquid 2 is changed to 17% by weight in terms of solid content, and the addition amount of the colorant dispersion liquid 1 is changed to 5.0% by weight in terms of solid content to stop aggregation. Toner base particles 11 were obtained in the same manner as in the manufacture of toner base particles 9 except that the system pH when the temperature reached 90 ° C. later was 7.0.
When the toner base particle diameter was measured with a Coulter counter, the cumulative volume average particle diameter D50 was 9.5 μm. Further, the circularity of the s particles determined from shape observation by FPIA was 0.973. The endothermic peak temperature measured by DSC was 112.2 ° C.

(Manufacture of toner mother particle (Black) 12)
In the production of the toner base particles 9, the addition amount of the release agent dispersion liquid 2 is changed to 18% by weight in terms of solid content, and the addition amount of the colorant dispersion liquid 4 is changed to 5.0% by weight in terms of solid content to stop aggregation. A toner 12 was obtained by operating in the same manner as in the production of the toner base particles 9 except that the pH in the system when the temperature reached 90 ° C. was changed to 6.8.
When the toner base particle diameter was measured with a Coulter counter, the cumulative volume average particle diameter D50 was 9.8 μm. Furthermore, the degree of circularity of the particles determined from shape observation by FPIA was 0.971. The endothermic peak temperature measured by DSC was 113.3 ° C.

Preparation of toner (1):
In each of toner base particles 1 to 4, 1.5 parts by weight of silica fine particles (RY50: manufactured by Nippon Aerosil Co., Ltd., number average particle size 85 nm) and 0.3 parts by weight of alumina are used with respect to 100 parts by weight of toner base particles. Fine particles (AKP-G015: manufactured by Sumitomo Chemical Co., Ltd., number average particle size 40 nm), 0.8 parts by mass of titanium oxide fine particles (STT100: manufactured by Titanium Industry Co., Ltd., number average particle size 30 nm), 1.0 parts by mass of poly Methyl methacrylate resin fine particles (MP-1451: manufactured by Soken Chemical Co., Ltd., number average particle diameter 150 nm) were mixed with a Henschel mixer to obtain toners 1 to 4.

  The number average particle size is determined by adding the external additive alone to the toner, dispersing the external additive on the toner surface, and observing the toner surface with a scanning electron microscope (SEM). It was measured by counting and averaging the major axis diameter and the number of external additive particles.

Toner preparation (2):
For each of the toner base particles 5 to 8, 1.0 part by weight of silica fine particles (RX50: manufactured by Nippon Aerosil Co., Ltd., number average particle size 80 nm) and 0.2 parts by weight of alumina fine particles with respect to 100 parts by weight of the toner base particles. (AKP-G025: number average particle size 25 nm), 0.8 parts by mass of titanium oxide fine particles (STT100: number average particle size 30 nm), 1.3 parts by mass of crosslinked polymethyl methacrylate resin fine particles (MP-300: Soken) Chemicals, number average particle size 120 nm) were mixed with a Henschel mixer to obtain toners 5-8.

Preparation of toner (3):
In each of toner base particles 5 to 8, 1.0 part by mass of silica fine particles (RY50: number average particle size 80 nm) and 0.2 parts by mass of alumina fine particles (AKP-G015: 100 parts by mass of toner base particles). Number average particle size 40 nm), 1.0 part by mass of titanium oxide fine particles (STT100: number average particle size 30 nm), 1.0 part by mass of crosslinked polymethyl methacrylate resin fine particles (MP-300: manufactured by Soken Chemical Co., Ltd., number The average particle size of 120 nm) was mixed with a Henschel mixer to obtain toners 9 to 12.

Preparation of toner (4):
For each of the toner base particles 1 to 4, 1.5 parts by mass of silica (RX50: number average particle size 80 nm) and 0.4 parts by mass of alumina fine particles (AKP-G025: number) with respect to 100 parts by mass of the toner base particles. Average particle size 25 nm), 1.2 parts by mass of titanium oxide fine particles (STT100: number average particle size 30 nm), 1.0 parts by mass of crosslinked polymethylmethacrylate resin fine particles (MP-300: manufactured by Soken Chemical Co., Ltd., number average) Toners 13 to 16 were obtained by mixing with a Henschel mixer.

Preparation of toner (5):
In each of toner base particles 9 to 12, 1.5 parts by weight of hydrophobic silica fine particles (RX-200: manufactured by Nippon Aerosil Co., Ltd., number average particle diameter 20 nm), 0.4 parts by weight with respect to 100 parts by weight of toner base particles. Part of alumina fine particles (AKP-3000: manufactured by Sumitomo Chemical Co., Ltd., number average particle size 60 nm), 1.2 parts by mass of titanium oxide fine particles (STR-40: manufactured by Sakai Chemical Industry Co., Ltd., number average particle size 70 nm). 0 parts by mass of polymethyl methacrylate resin fine particles (MP-1100: manufactured by Soken Chemical Co., Ltd., number average particle size 400 nm) were mixed with a Henschel mixer to obtain toners 17 to 20.

Preparation of toner (6):
Toners 21 to 24 were obtained in the same manner as in Preparation of toner (1) except that hydrophobic silica fine particles were not added.

Preparation of toner (7):
Toners 25 to 28 were obtained in the same manner as in Toner Preparation (1) except that no alumina fine particles were added.

Preparation of toner (8):
Toners 29 to 32 were obtained in the same manner as in toner preparation (1) except that titanium oxide fine particles were not added.

Preparation of toner (9):
Toners 33 to 36 were obtained in the same manner as in toner preparation (1) except that the polymethyl methacrylate resin fine particles were not added.

Developer development:
Each of the toners 1 to 36 is weighed so that the toner concentration is 7 parts by mass with respect to 100 parts by mass of a ferrite carrier having a volume average particle size of 50 μm coated with 1% by weight of methacrylate (manufactured by Soken Chemical Co., Ltd.) Stir and mix in a ball mill for 5 minutes to develop developer 1-4, developer 5-8, developer 9-12, developer 13-16, developer 17-20, developer 21-24, developer 25- 28, developers 29 to 32, and developers 33 to 36 were obtained.

[Example 1]
The developer of four colors developer 1-4 is made by Fuji Xerox, a DPC2200 remodeling machine using a charging roll for the charger (removing the photoconductor cleaning blade and remodeling so that a roll-shaped brush can be attached) 50,000 images are printed in the HH environment (30 ° C / 90% RH) and LL environment (10 ° C / 30% RH), respectively, while maintaining the density, reproducibility of fine lines, and images. Defects, ghosts, and background fog were evaluated.

For the ghost, a level that can hardly be visually observed on the print is indicated by ◯, a level that can be slightly observed is Δ, and a level that can be clearly observed is indicated by ×.
The concentration was measured with a Macbeth densitometer.
For image defects, the level at which streak-out, white spots, and color points could hardly be visually observed was indicated by ◯, the level at which slight observation was possible was indicated by Δ, and the level at which clear observation was possible was indicated by x.
The reproducibility of the thin line was defined as ○ when the level at which one dot line was clearly reproduced visually, Δ when the level was slightly faint, and x when the line was faint and not continuous. Of the above evaluation indexes, Δ and ○ mean that there is no practical problem.
The results are shown in Table 1 below.

[Example 2]
The same evaluation as in Example 1 was performed using developers 5 to 8. The results are shown in Table 2 below.

Example 3
The same evaluation as in Example 1 was performed using developers 9 to 12. The results are shown in Table 3 below.

Example 4
The same evaluation as in Example 1 was performed using the developers 13 to 16. The results are shown in Table 4 below.

[Comparative Example 1]
The same evaluation as in Example 1 was performed using developers 17 to 20. The results are shown in Table 5 below.

[Comparative Example 2]
The same evaluation as in Example 1 was performed using the developers 21 to 24. The results are shown in Table 6 below.

[Comparative Example 3]
The same evaluation as in Example 1 was performed using developers 25 to 28. The results are shown in Table 7 below.

[Comparative Example 4]
The same evaluation as in Example 1 was performed using the developers 29 to 32. The results are shown in Table 8 below.

[Comparative Example 5]
The same evaluation as in Example 1 was performed using the developers 33 to 36. The results are shown in Table 9 below.

[Comparative Example 6]
A developer was prepared in the same manner as in Example 1 except that hydrophobic silica fine particles (R-972: manufactured by Nippon Aerosil Co., Ltd.) having a number average particle diameter of 20 nm were used, and the same evaluation as in Example 1 was performed. went. The results are shown in Table 10 below.

[Comparative Example 7]
A developer was prepared in the same manner as in Example 1 except that spherical silica fine particles prepared by a sol-gel method having a number average particle size of 115 nm were used, and evaluation similar to that in Example 1 was performed. The results are shown in Table 11 below.

Example 5
A developer was prepared in the same manner as in Example 1 except that hydrophobic silica fine particles (TS720: manufactured by Cabot) having a number average particle diameter of 35 nm were used, and the same evaluation as in Example 1 was performed. The results are shown in Table 12 below.

From the above results, when the developers of Examples 1 to 5 were used, they were superior in the long-term density maintenance than the developers of the comparative examples, and the image quality defects, ghosts, background fogging, and fine line reproducibility were also good. It was confirmed that there was.

Claims (3)

A toner containing at least a binder resin, a colorant and an external additive,
The external additive is aluminum oxide fine particles having a number average particle size of 5 to 50 nm, titanium oxide fine particles having a number average particle size of 5 to 50 nm, silica fine particles having a number average particle size of 30 to 100 nm, and number average particle size of 50. A toner characterized by at least four kinds of resin fine particles of ˜300 nm.   A developer comprising the toner according to claim 1. A latent image forming step of forming a latent image on the latent image carrier by performing a charging process; a developing step of developing the latent image using toner; and a transferring step of transferring the developed image after development to a transfer medium; And a cleaning step of removing the toner after transfer remaining on the latent image carrier,
The toner according to claim 1, wherein the toner is
The image forming method, wherein the cleaning means in the cleaning step is a means using at least one of a brush and a roll.