JP5494391B2 - Developer, toner cartridge, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developer, a toner cartridge, a process cartridge, and an image forming apparatus.

  For the purpose of forming an image having a brightness such as a metallic luster, a developer containing toner is used.

For example, Patent Document 1 proposes a toner including a colorant in which a bright pigment obtained by coating silver on a flat glass flake is internally added.
Patent Document 2 proposes a metal toner that is used in a developer for forming a conductor pattern by electrophotography, and in which metal particles are coated with a thin film layer of a surface treatment agent.
Patent Document 3 proposes a toner containing a light reflecting material. As the light reflecting material, metal powder, alloy powder, flake-shaped metal powder, flake-shaped alloy powder, flake coated with metal are used. It has been proposed to use at least one selected from the group consisting of shaped powders, metal pastes, and alloy pastes.

Patent Document 4 proposes a toner containing, as a colorant, a metal foil having a thickness of 1 nm to 10 nm and a longitudinal direction of 80 nm to 1500 nm.
Patent Document 5 discloses that any one of a metal powder, an inorganic compound powder, or a mixed raw material powder thereof is used as a toner powder for circuit formation, and an amino group is formed on the particle surface of the core material particles as a carrier used together with the toner powder. It has been proposed to use a carrier having a resin coating layer using an acrylic resin composition containing a containing polymer.

JP 2003-207941 A JP 2003-270846 A JP 2004-061822 A JP 2009-217053 A JP 2009-244573 A

  An object of the present invention is to provide a developer that maintains the glitter of an image before repeated image formation even after repeated image formation as compared with the case where the carrier and toner in the present invention are not used. It is to provide.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1 of the present invention contains scaly pigment particles, the average equivalent circle diameter D is longer than the average maximum thickness C, and the cross section in the thickness direction was observed. Of all the pigment particles observed in this case, the number of pigment particles in which the angle between the major axis direction of the cross section and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is the total content particle to be observed When a solid image is formed, the reflectance at a light receiving angle of + 30 ° measured when incident light having an incident angle of −45 ° is irradiated to the image by a goniophotometer. The first resin film and the electrical conductivity are formed on a core including a toner having a ratio of A to a reflectance B at a light receiving angle of −30 ° (A / B) of 2 to 100, a magnetic powder, and a resin. And a carrier having the second resin film in this order.

The invention according to claim 2 is the developer according to claim 1, wherein an average film thickness of the first resin film in the carrier is equal to or greater than an average film thickness of the second resin film.
In the invention according to claim 3, the average film thickness of the first resin film is in the range of 2 times to 10 times when the average film thickness of the second resin film is 1. Developer.

According to 請 Motomeko 4 invention, the average maximum thickness C and the ratio of the average equivalent circle diameter D (C / D) is in the range of 0.001 to 0.500 or less claims 1 in the toner Item 4. The developer according to any one of Item 3 .

A fifth aspect of the present invention is a toner cartridge containing the developer according to any one of the first to fourth aspects.
The invention according to claim 6 is an image holding member, a charging device for charging a member to be charged, a latent image forming device for forming an electrostatic latent image on the member to be formed, and a transfer device for transferring a toner image to a recording member. A process cartridge comprising at least one of them and a developing device that develops the electrostatic latent image as a toner image with the toner contained in the developer according to any one of claims 1 to 4 .

According to a seventh aspect of the present invention, there is provided an image holding member, a charging device that charges the image holding member, a latent image forming device that forms an electrostatic latent image on the image holding member, and the electrostatic latent image. imaging with a developing device for developing as a toner image by a toner contained in the developer according to 1 to claim 4, and a transfer device of the toner image formed on the image carrier is transferred to a recording member Device.

According to the first aspect of the present invention, as compared with the case where the carrier and the toner in the present invention are not used, the resistance change is suppressed even after the image formation is repeatedly performed, the development amount is stabilized, and the repetition is repeated. There is provided a developer capable of maintaining the glitter of an image before image formation.

  According to the second aspect of the present invention, even after the image formation is repeated as compared with the case where the average film thickness of the first resin film is less than the average film thickness of the second resin film. The thickness of the first resin film suppresses carrier contamination and surface deterioration due to the toner component, and provides a developer that can further maintain the glitter of an image before repeated image formation.

According to the invention of 請 Motomeko 1 and claim 4, in comparison with the case of not using the toner of the present invention, even after the image formation was repeatedly performed, glitter of the repetition of the image formation before the image Is further maintained.

According to the fifth aspect of the present invention, the brightness of an image before repeated image formation is maintained even after repeated image formation as compared with the case where the developer in the present invention is not used. A toner cartridge is provided.
According to the sixth aspect of the present invention, the brightness of the image before repeated image formation is maintained even after repeated image formation, as compared with the case where the developer in the present invention is not used. A process cartridge is provided.

According to the seventh aspect of the present invention, the brightness of an image before repeated image formation is maintained even after repeated image formation as compared with the case where the developer in the present invention is not used. An image forming apparatus is provided.

FIG. 3 is a cross-sectional view schematically illustrating a toner according to an exemplary embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus to which the exemplary embodiment is applied. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described in detail.
≪Developer≫
The developer according to this embodiment is a two-component developer including toner and carrier.
The toner contained in the developer of the present embodiment has glossiness and is measured when incident light having an incident angle of −45 ° is irradiated to the image with a goniophotometer when a solid image is formed. The toner has a ratio (A / B) of the reflectance A at a light receiving angle of + 30 ° and the reflectance B at a light receiving angle of −30 ° of 2 to 100. Further, the toner contained in the developer of the present embodiment contains scale-like pigment particles, and is a toner that satisfies the requirements (1) and (2) described later.
Here, “brightness” indicates that the image formed with the toner has a brightness such as a metallic luster when viewed visually.
The carrier included in the developer of the present embodiment is a carrier having a first resin film and a conductive second resin film in this order on a core including magnetic powder and resin.

The developer in the present embodiment is configured as described above, so that the pigment contained in the toner is exposed to the outside of the toner or dropped from the toner as compared with the case where the toner and the carrier in the present embodiment are not used. It is thought that it is suppressed. For this reason, the developer in the present embodiment has a brightness of an image before repeated image formation, even after image formation is repeated, as compared with the case where the toner and carrier in the present embodiment are not used. It is thought that gender is maintained.
Details of each component will be described below.

<Toner>
As described above, the toner according to the exemplary embodiment has glossiness and is measured when incident light with an incident angle of −45 ° is irradiated to the image with a goniophotometer when a solid image is formed. The toner has a ratio (A / B) of the reflectance A at a light receiving angle of + 30 ° and the reflectance B at a light receiving angle of −30 ° of 2 to 100.

A ratio (A / B) of 2 or more means that there is more reflection on the side opposite to the incident side (angle + side) than on the side on which incident light enters (angle-side). That is, the irregular reflection of the incident light is suppressed. When irregular reflection occurs in which incident light is reflected in various directions, the color looks dull when the reflected light is visually confirmed. Therefore, when the ratio (A / B) is less than 2, it is considered that the gloss cannot be confirmed even when the reflected light is visually recognized, and the glitter is inferior.
On the other hand, when the ratio (A / B) exceeds 100, it is considered that the viewing angle at which the reflected light can be visually recognized becomes too narrow, and the specularly reflected light component is large, so that it looks black depending on the viewing angle. Further, a toner having a ratio (A / B) exceeding 100 is difficult to manufacture.

  The ratio (A / B) is more preferably 20 or more and 90 or less, and particularly preferably 40 or more and 80 or less.

Measurement of the ratio (A / B) with a goniophotometer First, the incident angle and the light receiving angle will be described. In this embodiment, when measuring with a goniophotometer, the incident angle is set to −45 ° because the measurement sensitivity is high for an image in a wide range of glossiness.
The reason why the light receiving angle is set to −30 ° and + 30 ° is that the measurement sensitivity is the highest for evaluating images with glitter and images without glitter.

Next, a method for measuring the ratio (A / B) will be described.
In this embodiment, when measuring the ratio (A / B), a “solid image” is first formed by the following method. The developer used as a sample is charged in a developing device of DocuCentre-III C7600 manufactured by Fuji Xerox Co., Ltd., and on a recording paper (OK top coat + paper, manufactured by Oji Paper Co., Ltd.), a fixing temperature of 190 ° C., A solid image with a toner loading of 4.5 g / cm ² is formed at a fixing pressure of 4.0 kg / cm ² . The “solid image” refers to an image with a printing rate of 100%.

Using a spectral variable angle color difference meter GC5000L manufactured by Nippon Denshoku Industries Co., Ltd. as a variable angle photometer, incident light having an incident angle of −45 ° is incident on the solid image. The reflectance A at an angle of + 30 ° and the reflectance B at a light receiving angle of −30 ° are measured. The reflectance A and reflectance B were measured at intervals of 20 nm for light having a wavelength in the range of 400 nm to 700 nm, and the average value of the reflectance at each wavelength was used. The ratio (A / B) is calculated from these measurement results.
In the measurement of the A / B ratio in the toner, as a carrier contained in the developer, a resin carrier containing magnetic powder such as magnetite is obtained by a polymerization reaction to obtain core particles, and then the first, As the two layers, a carrier having a coating resin whose hardness is higher in the first layer than in the second layer was used for measurement. Specifically, the coating resin used was obtained from an epoxy resin and a first layer obtained with an amino curing agent and a styrene methacrylate copolymer resin.

<Configuration of toner>
The toner according to the present embodiment is for satisfying the following requirements (1) and (2) from the viewpoint of satisfying the aforementioned ratio (A / B).
(1) The average equivalent circle diameter D is longer than the average maximum thickness C of the toner.
(2) When the cross section in the thickness direction of the toner is observed, the angle between the major axis direction of the toner in the cross section and the major axis direction of the pigment particles is −30 ° to +30 out of all the observed pigment particles. The number of pigment particles in the range of ° is 60% or more of the total content particles observed

Here, FIG. 1 is a cross-sectional view schematically showing a toner that satisfies the requirements (1) and (2) . The schematic diagram shown in FIG. 1 is a cross-sectional view in the thickness direction of the toner.
A toner 2 shown in FIG. 1 is a flat toner having a circle-equivalent diameter longer than a thickness L, and contains scale-like pigment particles 4.

As shown in FIG. 1, when the toner 2 has a flat shape having a circle-equivalent diameter larger than the thickness L, the toner moves to an image carrier, an intermediate transfer body, a recording medium, etc. in the image forming development process and the transfer process. At this time, since the toner tends to move so as to cancel the charge to the maximum, it is considered that the toners are arranged so that the area to be adhered becomes the maximum. That is, on the recording medium to which the toner is finally transferred, it is considered that the flat toner is arranged so that the flat surface side faces the recording medium surface. Also in the fixing step of image formation, it is considered that the flat toner is aligned so that the flat surface side faces the recording medium surface due to the pressure during fixing.
Therefore, among the scale-like pigment particles contained in the toner, “the angle between the major axis direction in the cross section of the toner and the major axis direction of the pigment particles is −30 ° to + 30 ° shown in the above (2) . It is considered that the pigment particles satisfying the requirement “in the range” are arranged so that the surface side having the largest area faces the recording medium surface. When the image thus formed is irradiated with light, the ratio of the pigment particles that diffusely reflect the incident light is suppressed, so that the above range (A / B) can be achieved. .

  Next, the toner composition according to the exemplary embodiment will be described.

-Pigment-
For example, the following pigment particles are used as the pigment particles having the glitter property used in the toner according to the present embodiment. Metal powders such as aluminum, brass, bronze, nickel, stainless steel, zinc, etc.Coated flaky inorganic crystal substrates such as mica coated with titanium oxide or yellow iron oxide, barium sulfate, layered silicate, layered aluminum silicate, There are no particular restrictions on monocrystalline plate-like titanium oxide, basic carbonate, acid bismuth oxychloride, natural guanine, flaky glass powder, flaky glass powder deposited with metal, etc., as long as they have glitter.

  In the toner according to the exemplary embodiment, the content of the pigment is preferably 1 part by mass or more and 70 parts by mass or less, and more preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin described later. .

-Binder resin-
Examples of the binder resin used in the present embodiment include ethylene resins such as polyester, polyethylene, and polypropylene; styrene resins such as polystyrene and α-polymethylstyrene; and (meth) acrylic resins such as polymethyl methacrylate and polyacrylonitrile. Resin; Polyamide resin, polycarbonate resin, polyether resin and copolymer resins thereof may be used. Among these, it is desirable to use a polyester resin.
In the following, polyester resins that are particularly preferably used will be described.

The polyester resin according to this embodiment is obtained, for example, mainly by condensation polymerization of polyvalent carboxylic acids and polyhydric alcohols.
Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids; maleic anhydride, fumaric acid, succinic acid, Examples thereof include aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and one or more of these polycarboxylic acids are used.
Among these polycarboxylic acids, aromatic carboxylic acids are preferably used, and trivalent or higher carboxylic acids (trimellitic acid) together with dicarboxylic acids to form a crosslinked structure or a branched structure in order to ensure good fixing properties. And acid anhydrides thereof) are preferably used in combination.

Examples of the polyhydric alcohol include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, and glycerin; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol And alicyclic diols such as A; aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols are used.
Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure better fixability, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to form a crosslinked structure or a branched structure.

As described above, the toner according to the exemplary embodiment preferably contains a crystalline polyester resin as a binder resin. Of the crystalline polyester resins, aromatic crystalline resins are generally higher than the melting point range described later, and are preferably aliphatic crystalline polyester resins.
The content of the crystalline polyester resin in the toner according to the exemplary embodiment is preferably 2% by mass or more and 30% by mass or less, and more preferably 4% by mass or more and 25% by mass or less.

  The melting point of the crystalline polyester resin is preferably in the range of 50 ° C. or higher and 100 ° C. or lower, preferably in the range of 55 ° C. or higher and 95 ° C. or lower, and more preferably in the range of 60 ° C. or higher and 90 ° C. or lower. .

  Note that the “crystalline polyester resin” according to the present embodiment is not a stepwise endothermic change in differential scanning calorimetry (hereinafter sometimes abbreviated as “DSC”). It has an endothermic peak. The crystalline polyester resin is a polymer obtained by copolymerizing other components with respect to the main chain. When the other components are 50% by mass or less, the copolymer is also called crystalline polyester.

  The crystalline polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the following, the “acid-derived constituent component” refers to a polyester resin before the synthesis of the polyester resin. Refers to a component that was an acid component, and “alcohol-derived component” refers to a component that was an alcohol component before the synthesis of the polyester resin.

[Acid-derived components]
Examples of the acid for forming the acid-derived constituent component include various dicarboxylic acids, but the acid-derived constituent component in the crystalline polyester resin according to this embodiment is preferably a linear aliphatic dicarboxylic acid.
For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof, An acid anhydride may be mentioned, but not limited thereto. Among these, adipic acid, sebacic acid, and 1,10-decanedicarboxylic acid are preferable.

As the acid-derived constituent component, other constituent components such as a dicarboxylic acid-derived constituent component having a double bond and a dicarboxylic acid-derived constituent component having a sulfonic acid group may be contained.
Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt and the like are preferable.
Content of acid-derived components other than these aliphatic dicarboxylic acid-derived components (dicarboxylic acid-derived components having double bonds and / or dicarboxylic acid-derived components having sulfonic acid groups) in the acid-derived components Is preferably 1 component mol% or more and 20 component mol% or less, more preferably 2 component mol% or more and 10 component mol% or less.

  In the present specification, “constituent mol%” means that the acid-derived constituent component in the entire acid-derived constituent component in the polyester resin or the alcohol constituent component in the entire alcohol-derived constituent component is 1 unit (mol). ) Indicates the percentage.

[Alcohol-derived components]
As the alcohol to be an alcohol-derived constituent component, an aliphatic diol is desirable, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol. 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-dodecanediol, 1,12-undecanediol, 1,13-tridecanediol 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, and the like, but are not limited thereto. Among these, ethylene glycol, 1,4-butanediol, and 1,6-hexanediol are preferable.

  In this embodiment, the molecular weight of the polyester resin was measured and calculated by GPC (Gel Permeation Chromatography). Specifically, HPC-8120 manufactured by Tosoh Corporation was used for GPC, TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation was used for the column, and the polyester resin was measured with a THF solvent. Next, the molecular weight of the polyester resin was calculated using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

(Production method of polyester resin)
There is no restriction | limiting in particular as a manufacturing method of a polyester resin, It manufactures with the general polyester polymerization method which makes an acid component and an alcohol component react. For example, direct polycondensation, transesterification, and the like are used depending on the type of monomer. The molar ratio (acid component / alcohol component) at the time of reacting the acid component with the alcohol component varies depending on the reaction conditions and the like, and thus cannot be generally described. However, in order to increase the molecular weight, it is usually 1/1. The degree is preferred.

  Catalysts that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound; phosphorous acid compound; phosphoric acid compound; and amine compound.

-Release agent-
The toner according to the exemplary embodiment may contain a release agent as necessary. Examples of the release agent include paraffin wax such as low molecular weight polypropylene and low molecular weight polyethylene; silicone resin; rosins; rice wax; carnauba wax; The melting point of these release agents is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 95 ° C. or lower.
The content of the release agent in the toner is desirably 0.5% by mass or more and 15% by mass or less, and more desirably 1.0% by mass or more and 12% by mass or less.

-Other additives-
In addition to the components described above, various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles may be added to the toner according to the exemplary embodiment as necessary. .

  Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  As the inorganic particles, for example, known inorganic particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, or those obtained by hydrophobizing the surface thereof may be used alone or in combination of two or more kinds. Good. Among these, silica particles having a refractive index smaller than that of the binder resin are preferably used. Further, the silica particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a silicone oil or the like are preferably used.

-Toner characteristics-
・ Average maximum thickness C and average equivalent circle diameter D
As shown in (1) above, the toner according to the exemplary embodiment preferably has an average equivalent circle diameter D longer than the average maximum thickness C. The ratio (C / D) of the average maximum thickness C to the average equivalent circle diameter D is preferably in the range of 0.001 to 0.500, and more preferably in the range of 0.010 to 0.200. A range of 0.050 or more and 0.100 or less is particularly preferable.
When the ratio (C / D) is 0.001 or more, the strength of the toner is ensured, breakage due to stress during image formation is suppressed, charging is reduced due to exposure of the pigment, and fog is generated as a result. Is suppressed. On the other hand, when it is 0.500 or less, excellent glitter can be obtained.

The average maximum thickness C and the average equivalent circle diameter D are measured by the following methods.
The toner is placed on a smooth surface, and is vibrated and dispersed so that there is no unevenness. For 1000 toners, the color laser microscope “VK-9700” (manufactured by Keyence Corporation) was magnified 1000 times to measure the maximum thickness C and the equivalent circle diameter D of the surface viewed from above, and the arithmetic average of them. Calculate by finding the value.

The angle between the major axis direction in the cross section in the thickness direction of the toner and the major axis direction of the pigment particles As shown in (2) above, all the pigments observed when the cross section in the thickness direction of the toner is observed Among the particles, the number of pigment particles in which the angle between the major axis direction of the cross section of the toner and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is 60% or more of the total content particles observed. It is preferable that Furthermore, the number is more preferably 70% or more and 95% or more, and particularly preferably 80% or more and 90% or less. When the number is 60% or more, excellent glitter can be obtained.

Here, a method for observing the cross section of the toner will be described.
After embedding the toner with a bisphenol A liquid epoxy resin and a curing agent, a cutting sample is prepared. Next, the cutting sample is cut at −100 ° C. using a cutting machine using a diamond knife (in this embodiment, a LEICA ultramicrotome (manufactured by Hitachi Technologies)) to prepare an observation sample. A cross section of the toner particles is observed with a transmission electron microscope (TEM) at a magnification of about 5000 times. With respect to the 1000 toners observed, the number of pigment particles in which the angle between the major axis direction of the cross section of the toner and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is determined using image analysis software. Count and calculate the percentage.

  The “major axis direction in the cross section of the toner” means a direction orthogonal to the thickness direction in the toner having an average equivalent circle diameter D longer than the average maximum thickness C described above. “Direction” represents the length direction of the pigment particles.

  The volume average particle size of the toner according to the exemplary embodiment is preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and 20 μm or less, and further preferably 5 μm or more and 10 μm or less.

Incidentally, the volume average particle diameter D ₅₀ is Multisizer II - volume relative (Beckman Coulter) the measured particle size ranges which are divided based on the particle size distribution measuring apparatus such as a (channel), the number The cumulative distribution is drawn from the small diameter side, the particle diameter that becomes 16% cumulative is the volume D _16v , several D _16p , the particle diameter that becomes 50% cumulative is the volume D _50v , the number D _50p , and the particle diameter that becomes cumulative 84%. It is defined as a volume D _84v and a number D _84p . Using these, the volume average particle size distribution index (GSDv) is calculated as ( _D84v / _D16v ) ^1/2 .
Hereinafter, this method is used as the method for measuring the average particle size of the ground in this specification.

<Toner production method>
The toner according to the exemplary embodiment is manufactured by a known method such as a wet method or a dry method, and it is particularly preferable that the toner is manufactured by a wet method. Examples of the wet method include a melt suspension method, an emulsion aggregation method, a dissolution suspension method, and the like.
Here, the emulsion aggregation method is to prepare each dispersion (emulsion, pigment dispersion, etc.) containing components (binder resin, colorant, etc.) contained in the toner, and mix and mix these dispersions. And then the aggregated particles are higher than the melting point or glass transition temperature of the binder resin (in the case of producing a toner containing both the crystalline resin and the non-crystalline resin, the non-crystalline In this method, the toner components are aggregated and united by heating to a temperature higher than the glass transition temperature of the resin.

As described above, in the present exemplary embodiment, a toner having the requirements (1) and (2) is desirable. If the toner is produced by an emulsion aggregation method, the toner may be produced by, for example, the following production method. Prepared by
First, pigment particles are prepared, and the pigment particles and the binder resin are dispersed and dissolved in a solvent and mixed. By dispersing this in water by phase inversion emulsification or shear emulsification, bright pigment particles coated with a resin are formed. Other compositions (for example, mold release agent, shell resin, etc.) are added here, and further an aggregating agent is added. While stirring, the temperature is raised to near the glass transition temperature (Tg) of the resin, Form. In this step, for example, by using a stirring blade that forms a laminar flow having two paddles and stirring is performed at a high stirring speed (for example, 500 rpm or more and 1500 rpm or less), the glitter pigment particles are contained in the aggregated particles. Thus, the orientation in the major axis direction is aligned, and the agglomerated particles also aggregate in the major axis direction, so that the toner thickness is reduced (that is, the requirement (1) is satisfied). Finally, after making the particles alkaline for particle stabilization, the temperature is raised to the glass transition temperature (Tg) or higher and the melting point (Tm) or lower of the toner to coalesce the aggregated particles. In this coalescing step, coalescence is performed at a lower temperature (for example, 60 ° C. or more and 80 ° C. or less), thereby reducing the movement accompanying the rearrangement of the material, maintaining the orientation of the pigment, and satisfying the requirement (2) A full toner is obtained.

  In addition, as said stirring speed, 650 rpm or more and 1130 rpm or less are further preferable, and 760 rpm or more and 870 rpm or less are especially preferable. Further, the coalescence temperature in the coalescence step is more preferably 63 ° C. or more and 75 ° C. or less, and particularly preferably 65 ° C. or more and 70 ° C. or less.

-External additive-
In the present embodiment, an external additive such as a fluidizing agent or an auxiliary agent may be added to the surface of the toner particles. Examples of external additives include known particles such as silica particles whose surfaces have been hydrophobized, titanium oxide particles, alumina particles, cerium oxide particles, inorganic particles such as carbon black, and polymer particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Is used.

<Career>
The carrier contained in the developer of the present embodiment has a first resin film and a conductive second resin film in this order on a core containing magnetic powder and resin.

-core-
The core included in the carrier of the developer of the present embodiment includes magnetic powder and resin.
Examples of the magnetic powder include magnetite, ferrite (γ iron oxide, Mn—Zn ferrite, Ni—Zn ferrite, Mn—Mg ferrite, Li ferrite, Cu—Zn ferrite), iron such as maghematite, and the like. Examples thereof include system oxides. Among these, ferrite, magnetite, and maghematite are desirable as the magnetic powder from the viewpoint of magnetic stability.

  As the resin used for the core, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, Examples include, but are not limited to, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, and epoxy resins. In addition, these may be used independently and may mix and use several resin.

  The core in the carrier used in the present embodiment is a resin particle in which the magnetic powder is dispersed in the resin. Examples of the volume average particle diameter of the core (resin particles) include a range of 10 μm to 500 μm and a range of 30 μm to 100 μm.

  The content of the magnetic powder in the core may be within a range in which carrier adhesion to the photoreceptor, developer spillage from the developing machine does not occur, and the binding effect by the resin is sufficiently obtained. The range of 100 parts by mass or more and 300 parts by mass or less and the range of 150 parts by mass or more and 250 parts by mass or less can be mentioned with respect to 100 parts by mass of the resin contained in the carrier.

  As a method for producing the core, known methods can be mentioned. For example, as a core production method, the magnetic powder and the resin are melt-kneaded using a Banbury mixer, a kneader, etc., cooled, pulverized and classified, or the resin monomer unit and magnetic resin Examples include a suspension polymerization method in which powder is dispersed in a solvent to prepare a suspension, and this suspension is polymerized, or a spray drying method in which magnetic powder is mixed and dispersed in a resin solution and then spray-dried. It is done.

  The magnetic force of the core is preferably such that the saturation magnetization at 1000 Oersted is 50 emu / g or more from the viewpoint of suppressing the carrier from moving to the image carrier (photoreceptor) side together with the toner during image formation. More preferably, it is 60 emu / g or more.

  As a device for measuring the magnetic properties, a vibration sample type magnetic measuring device VSMP10-15 (manufactured by Toei Industry Co., Ltd.) is used. The measurement sample is packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. The measurement applies an applied magnetic field and sweeps up to 1000 oersted. Next, the applied magnetic field is decreased to create a hysteresis curve on the recording paper. Saturation magnetization, residual magnetization, and coercive force are obtained from the curve data. In the present embodiment, saturation magnetization refers to magnetization measured in a 1000 oersted magnetic field.

The volume resistivity (volume resistivity) of the core is in the range of 10 ⁵ Ω · cm to 10 ^9.5 Ω · cm, or 10 ⁷ Ω · cm to 10 10 from the viewpoint of improving image quality during image formation. Examples include a range of ⁹ Ω · cm or less.

The core volume resistivity (Ω · cm) is measured as follows. The measurement environment is a temperature of 20 ° C. and a humidity of 50% RH.
A measurement object layer is formed by placing the measurement object flat on the surface of a circular jig having a 20 cm ² electrode plate so as to have a thickness of 1 mm or more and 3 mm or less. A 20 cm ² (20 cm × 20 cm) electrode plate is placed thereon, and the measurement object layer is sandwiched therebetween. In order to eliminate the gap between the measurement objects, a thickness (cm) of the layer is measured after a load of 4 kg is applied on the electrode plate placed on the layer. Both electrodes above and below the layer are connected to an electrometer and a high voltage power generator. By applying a high voltage so that the electric field is 10 ^3.8 V / cm on both electrodes and reading the current value (A) flowing 3 seconds after the voltage application start, the volume electric resistance (Ω) of the measurement object Calculate cm). The calculation formula of the volume electrical resistance (Ω · cm) of the measurement object is as shown in the following formula.
Formula: R = E × 20 / (I−I ₀ ) / L

In the above formula, R is the volume electric resistance (Ω · cm) of the measurement object, E is the applied voltage (V), I is the current value (A), I ₀ is the current value (A) at the applied voltage of 0 V, and L is Each layer thickness (cm) is expressed. A coefficient of 20 represents the area (cm ² ) of the electrode plate.

-First resin film-
In the present embodiment, a first resin film is provided on the surface of the core constituting the carrier.
The first resin film has a function of adhering the core and the second resin film, a function of reducing a mechanical load on the toner, and suppressing a resistance variation of the carrier itself. .

  The first resin film may be any film that satisfies the above characteristics, but from the viewpoint of reducing mechanical load on the toner and making the second resin film provided on the first resin film more difficult to peel off. The average film thickness is preferably equal to or greater than the average film thickness of the second resin film. Specifically, as the average film thickness of the first resin film, specifically, when the average film thickness of the second resin film is 1, the range is 2 times or more and 10 times or less, or 3 times or more and 8 times or less. Range.

  In addition, the average film thickness of the first resin film is preferably smaller than the volume average particle diameter of the core from the viewpoint of high image quality by reducing the carrier diameter and stability of adhesion of the resin film to the core. Specifically, as the average film thickness of the first resin film, when the volume average particle size of the core is 1, the range of 0.005 times or more and 0.1 times or less, or 0.0075 times or more The range of 0.085 times or less is mentioned.

  In addition, as the average film thickness of the first resin film, specifically, the total sum with the second resin film described later is in the range of 0.3 μm to 5 μm, and 0.5 μm to 3 μm. It is further desirable to adjust so that. Since the sum of the average film thickness of the first resin film and the average film thickness of the second resin film is within the above range, the first resin film and the second resin film are formed on the surface of the core. It is thought that it is easy to form uniformly, and aggregation of formed carriers is also suppressed.

In addition, the average film thickness of the first resin film is expressed as follows. The specific gravity of the core is ρ _D , the average particle diameter of the core is D, the average specific gravity of the first resin film is ρ _C , and the total coating amount by the first resin film is When W _C is used, it is easily calculated by the following formula.

Average film thickness (l) = [amount of first resin film per carrier (including additives contained in first resin film) / surface area per carrier] / average of first resin film Specific gravity = [4 / 3π · (D / 2) ³ · ρ _D · W _C ] / [4π (D / 2) ³ ] ÷ ρ _C = (1/6) · (D · ρ _D · W _C / ρ _C )

The first resin film is desirably insulative (volume resistance value is 10 ⁹ Ω · cm or more) in addition to the above-described characteristics.

  As the resin constituting the first resin film, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid Examples thereof include a copolymer, a straight silicone resin composed of an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin. In addition, these may be used independently and may mix and use several resin.

  Among them, as the resin constituting the first resin film, the compatibility parameter (SP value) is in an appropriate range from the viewpoint of improving the compatibility with the core and the compatibility with the second resin film. It is desirable to use a resin.

Specifically, when the resin contained in the core is an epoxy resin having a high compatibility parameter and the resin contained in the second resin film is a styrene methacryl resin having a low compatibility parameter, the first resin film is used. As the resin constituting the resin, it is desirable to use an epoxy resin having a compatibility parameter between two resins.
In addition, as a combination of the resin contained in the core, the resin constituting the first resin film, and the resin contained in the second resin film, the compatibility parameters are relatively different from each other in the core resin and the second resin film. There is no limitation to the above combination as long as the first resin is present between the resins.

  Moreover, this 1st resin film is good also as a structure containing various additives, such as electroconductive powder and a resin particle, as needed within the range with which the said characteristic is satisfy | filled.

Specific examples of the conductive powder that may be contained in the first resin film include metal particles such as gold, silver, and copper; carbon black; ketjen black; acetylene black; titanium oxide, zinc oxide, and the like. Semiconductive oxide particles; particles in which the surface of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder or the like is covered with tin oxide, carbon black, metal or the like; These may be used individually by 1 type and may use 2 or more types together.
The conductive powder that may be contained in the first resin film may be the same as or different from the conductive powder that may be contained in the second resin film. May be.

  As the conductive powder that may be contained in the first resin film, carbon black particles are desirable in terms of good production stability, cost, conductivity, and the like.

  Examples of other resin particles that may be included in the first resin film include thermoplastic resin particles and thermosetting resin particles. Among these, a thermosetting resin is desirable from the viewpoint of relatively easily increasing the hardness, and resin particles of a nitrogen-containing resin containing nitrogen atoms are desirable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together.

  As a method for providing the first resin film on the surface of the core, a resin for forming the first resin film in which the resin constituting the first resin film and various additives as necessary are dissolved in an appropriate solvent are used. (Hereinafter, it may be referred to as a first solution.) The solvent contained in the first solution is not particularly limited as long as it is a solvent that dissolves the resin constituting the first resin film, and is selected in consideration of the type of resin used, application suitability, and the like. do it. For example, examples of the solvent contained in the first solution include aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, and ethers such as tetrahydrofuran and dioxane.

  Specifically, as a method of providing the first resin film on the surface of the core, an immersion method in which the core is immersed in the first solution, a spray method in which the first solution is sprayed on the surface of the core, a core There are a fluidized bed method in which the first solution is sprayed in a state of being suspended by fluid air, a kneader coater method in which the core and the first solution are mixed in a kneader coater, and the solvent is removed.

  The coverage of the core with the first resin film is desirably 95% or more, and particularly desirably 97% or more. When the coverage of the core with the first resin film is within the above range, mechanical stress on the toner particles is reduced and adhesion of the toner component to the carrier surface is suppressed. Furthermore, since the resistance change of the carrier surface is suppressed, it is considered that the effect of maintaining the initial high quality image can be obtained even when used for a long period of time.

  The core coverage with the first resin film refers to the ratio [%] of the surface of the core covered with the first resin film, and is determined by XPS measurement. As an XPS measurement device, JPS80 manufactured by JEOL Ltd. is used, and measurement is performed by using MgKα ray as an X-ray source, setting an acceleration voltage to 10 kV and an emission current to 20 mV, and main elements constituting the resin layer (Usually carbon) and main elements constituting the core particle (for example, iron and oxygen when the core particle is an iron oxide-based material such as magnetite) are measured.

-Second resin film-
The second resin film is provided on the first resin film provided on the surface of the core. The second resin film is a conductive resin film.
Note that “conductive” in this embodiment means having a volume resistance of 10 ¹ Ω · cm to 10 ¹¹ Ω · cm. In this specification, the volume resistance of the second resin film refers to a value measured by the following method.
A second resin film having a thickness of 1 mm is formed on the electrode, and a load of 1 × 10 ⁴ kg / m ² is applied to the formed second resin film at room temperature and humidity by a metal member. . Then, a value calculated from a current value measured 3 seconds after applying a voltage generating an electric field of 10 ⁶ V / m between the metal member and the electrode is defined as a volume resistance value.

  The average film thickness of the second resin film is preferably such that the relationship with the average film thickness of the first resin film satisfies the relationship described above. The average film thickness of the second resin film when the volume average particle diameter of the core is 1 is preferably in the range of 0.001 times to 0.005 times, and more than 0.002 times to 0 A range of 0.003 times or less is more desirable.

  The average film thickness of the second resin film is desirably a thickness that satisfies the above relationship, and specifically includes, for example, a range of 0.05 μm or more and 0.5 μm or less.

  As for the average film thickness of the second resin film, similarly to the cross-sectional observation in the toner, a combination of TEM (transmission electron microscope) and a known method of image analysis is used to combine the first resin portion in the carrier cross-sectional image. Up to the second resin film portion is binarized, the equivalent circle diameter to the second resin portion is calculated, and subtracted from the equivalent circle diameter to the first portion. Furthermore, it is obtained as a representative value by repeatedly averaging this with 100 carriers. If binarization is difficult, the equivalent circle diameter is calculated by the TEM after the first resin film is formed, and the equivalent circle diameter is similarly calculated after the second resin film is formed and subtracted.

  As the second resin film, any film satisfying the above conditions may be used. Examples of the second resin film include a structure including a conductive resin and a structure including a conductive powder in the resin.

  When the second resin film includes a conductive resin, examples of the conductive resin include polyacetylene, polyacene, and polypyrrole.

  On the other hand, when the second resin film has a configuration in which conductive powder is dispersed in the resin, the resin may be a conductive resin or an insulating resin. Specifically, from polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, organosiloxane bond Straight silicone resin or modified product thereof, fluororesin, polyester, polycarbonate, phenol resin, epoxy resin and the like. In addition, these may be used independently and may mix and use several resin.

  Examples of the conductive powder dispersed in the resin contained in the second resin film include metals such as gold, silver, and copper; carbon black; and titanium oxide, magnesium oxide, zinc oxide, aluminum oxide, and calcium carbonate. Metal oxides such as aluminum borate, potassium titanate, calcium titanate powder; the surface of titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate powder, etc. with tin oxide, carbon black, or metal Covered fine powder; and the like. These may be used alone or in combination of two or more. Use of a metal oxide as the conductive powder is desirable because it can reduce the environmental dependency of charging characteristics, and titanium oxide is particularly desirable.

The shape of the conductive powder contained in the second resin film may be either acicular or spherical, but since it can be uniformly oriented with a small amount, it is acicular in terms of stress resistance and resistance control. It is desirable that “Needle” as used herein means that the ratio of the major axis (fiber length) to the minor axis (fiber diameter) (major axis / minor axis; hereinafter referred to as “aspect ratio”) is at least 3 or more. More desirably, it is 5 or more. Specifically, the acicular conductive powder preferably has a major axis of 0.05 μm or more and 20 μm or less. Even if the aspect ratio is 3 or more, if the major axis is shorter than 0.05 μm, the filler may be destroyed in the process of dispersing in the resin, and the effect may be reduced. On the other hand, the major axis is less than 20 μm. If the length is long, the conductive powder may be easily detached from the second resin film. Examples of the short axis of the acicular conductive powder include 0.01 μm or more and 1 μm or less. If the short axis of the conductive powder contained in the second resin film is within the above range, it is considered that dispersibility can be improved and variation in characteristics between carriers can be suppressed.
On the other hand, when a spherical conductive powder (the average value of the shape factor SF1 is 110 or less) is used as the conductive powder contained in the second resin film, the volume average particle size of the spherical conductive powder is: The range is preferably from 0.01 μm to 1 μm, more preferably from 0.01 μm to 0.5 μm, and particularly preferably from 0.05 μm to 0.45 μm. By making the volume average particle diameter of the spherical conductive powder within the above range, the dispersibility of the conductive powder in the second resin film is improved and the conductive powder is detached from the second resin film. Is considered to be suppressed.

The shape factor SF1 is obtained by the following equation.
Formula SF1 = ((absolute maximum length of conductive powder) ² / projected area of conductive powder) × (π / 4) × 100

In addition, the measuring method of the volume average particle diameter of electroconductive powder applies to the measuring method of the volume average particle diameter of the said core.
It is considered that when the volume average particle diameter of the conductive powder is within the above range, dropping of the conductive powder from the second resin film is suppressed, and a decrease in chargeability of the toner is suppressed.

Note that the conductive powder contained in the second resin film desirably has a volume resistance of 10 ¹ Ω · cm to 10 ¹¹ Ω · cm, and is preferably 10 ³ Ω · cm to 10 ⁹ Ω · cm. It is more desirable to have the following volume resistance. In addition, the volume electrical resistance of this electroconductive powder is measured with the following method.

Under normal temperature and normal humidity, the conductive powder is filled into a container having a cross-sectional area of 2 × 10 ⁻⁴ m ^{2 so} as to have a thickness of about 1 mm, and then on the filled conductive powder by a metal member, A load of 1 × 10 ⁴ kg / m ² is applied. The value calculated from the current value measured 3 seconds after applying a voltage generating an electric field of 10 ⁶ V / m between the metal member and the bottom electrode of the container is the volume resistance value of the conductive powder. And

  As content in this 2nd resin layer of this electroconductive powder, the range of 25 volume% or more and 45 volume% or less is mentioned, for example, The range of 30 volume% or more and 40 volume% or less is desirable. When the content of the conductive powder contained in the second resin layer is within the above range, the toner is charged to the extent necessary for forming the toner image contained in the developer.

  As a method of forming the second resin film on the surface of the first resin film, a solution containing the resin, conductive powder, and solvent (hereinafter referred to as a second solution) is prepared, Conductive powder is dispersed in the second solution. Examples of the method for dispersing the conductive powder include a sand mill, a dyno mill, and a homomixer. Then, this second solution is sprayed on the particles provided with the first resin film on the core, and the particles provided with the first resin film on the core are suspended by flowing air. Fluidized bed method in which the second solution is sprayed in a state, or a kneader coater in which the second solution is mixed with the particles provided with the first resin film on the core in a kneader coater, and the solvent is removed. Law.

The solvent used for the preparation of the second solution is not particularly limited as long as it dissolves the resin contained in the second resin film. For example, aromatic hydrocarbons such as toluene and xylene , Ketones such as acetone and methyl ethyl ketone, and ethers such as tetrahydrofuran and dioxane.

  The coverage of the core with the second resin film is desirably 95% or more, and particularly desirably 97% or more. Since the coverage of the core with the second resin film is within the above range, the carrier surface resistance control can be stably performed even for a long period of use, so that a high quality image is maintained for a long period of time. It is thought that a good effect can be obtained.

Second, the coating ratio of the core with the resin film refers to the ratio [%] of the surface of the core covered with the second resin film, and is obtained by XPS.
Specifically, JPS80 manufactured by JEOL Ltd. is used as the XPS measuring apparatus, and the measurement is performed using MgKα ray as the X-ray source, setting the acceleration voltage to 10 kV, and the emission current to 20 mV. And the main element constituting the core particle (for example, iron and oxygen when the core particle is an iron oxide-based material such as magnetite).

  In order to adjust the above-described coverage by each of the first resin film and the second resin film, the particles to be coated are dispersed and flowed in an air flow, and the solution of the film to be coated is sprayed. It is desirable to use a fluidized bed apparatus for coating.

  In the present embodiment, the volume average particle diameter of the carrier in which the first resin film and the second resin film are provided on the core is in the range of 15 μm to 50 μm, 25 μm to 40 μm. Range of

  The volume average particle size of the carrier is determined by measuring the particle size distribution using a laser diffraction / scattering type particle size analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER), and dividing the obtained particle size distribution into particle sizes. For the range (channel), the volume cumulative distribution is subtracted from the small particle diameter side, and the particle diameter at 50% accumulation is defined as the volume average particle diameter.

  Further, the shape factor SF1 of the carrier is desirably 100 or more and 145 or less from the viewpoint of realizing a high quality image and improving the toner and stirring efficiency in the developer.

The carrier shape factor SF1 means a value obtained by the following formula (III).
Formula (III): SF1 = 100π × (ML) ² / (4 × A)
Here, ML is the maximum length of the carrier particles, and A is the projected area of the carrier particles. The maximum length and projected area of the carrier particles are determined by observing the carrier particles sampled on the slide glass with an optical microscope and importing them into an image analyzer (LUZEX III, manufactured by NIRECO) through a video camera for image analysis. Is obtained by The number of samplings at this time is 100 or more, and the shape factor shown in the formula (III) can be obtained using the average value.

Examples of the saturation magnetization of the carrier include 40 emu / g or more and 50 emu / g or more.
As a device for measuring magnetic properties, a vibration sample type magnetic measuring device VSMP10-15 (manufactured by Toei Kogyo Co., Ltd.) is used. The measurement sample is packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. The measurement applies an applied magnetic field and sweeps up to 1000 oersted. Next, the applied magnetic field is decreased to create a hysteresis curve on the recording paper. Saturation magnetization, residual magnetization, and coercive force are obtained from the curve data. In an embodiment, saturation magnetization refers to magnetization measured in a 1000 oersted magnetic field.

The volume electric resistance of the carrier is desirably controlled in the range of 1 × 10 ⁷ Ω · cm to 1 × 10 ¹⁵ Ω · cm, and is preferably 1 × 10 ⁸ Ω · cm to 1 × 10 ¹⁴ Ω · cm. The range is more desirable, and the range of 1 × 10 ⁸ Ω · cm to 1 × 10 ¹³ Ω · cm is particularly desirable. The volume electric resistance of the carrier is measured in the same manner as the volume electric resistance of the magnetic particles.

  The mixing ratio (mass ratio) of toner and carrier in the developer of the present embodiment is preferably in the range of toner: carrier = 1: 100 to 30: 100, and in the range of 3: 100 to 20: 100. Is more desirable.

<Image forming apparatus>
FIG. 2 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus including a developing device to which the developer according to the present embodiment is applied.
In FIG. 1, the image forming apparatus according to the present embodiment includes a photoconductor 20 as an image carrier that rotates in a predetermined direction, and a charging device that charges the photoconductor 20 around the photoconductor 20. 21, for example, an exposure device 22 as a latent image forming device that forms an electrostatic latent image Z on the photosensitive member 20, and a developing device that visualizes the electrostatic latent image Z formed on the photosensitive member 20 30, a transfer device 24 that transfers a toner image visualized on the photoconductor 20 to a recording paper 28 that is a transfer target, and a cleaning device 25 that cleans residual toner on the photoconductor 20. Are arranged.

In the present embodiment, as shown in FIG. 2, the developing device 30 has a developing housing 31 in which a developer G containing toner 40 is accommodated, and the developing housing 31 faces the photoconductor 20 for development. In addition to opening the opening 32, a developing roll (developing electrode) 33 serving as a toner holding member is disposed facing the developing opening 32, and a developing bias determined by the developing roll 33 is applied, thereby exposing the photosensitive member. A developing electric field is formed in the developing region between the body 20 and the developing roll 33. Further, a charge injection roll (injection electrode) 34 as a charge injection member is provided in the development housing 31 so as to face the development roll 33. In particular, in this embodiment, the charge injection roll 34 also serves as a toner supply roll for supplying the toner 40 to the developing roll 33.
Here, the rotation direction of the charge injection roll 34 may be selected. However, in consideration of the toner supply property and the charge injection characteristic, the charge injection roll 34 has the same direction at the portion facing the developing roll 33. In addition, it is preferable that the rotation is performed with a peripheral speed difference (for example, 1.5 times or more), the toner 40 is sandwiched between regions where the charge injection roll 34 and the development roll 33 are sandwiched, and the charge is injected while being rubbed.

Next, the operation of the image forming apparatus according to the embodiment will be described.
When the image forming process is started, first, the surface of the photoconductor 20 is charged by the charging device 21, and the exposure device 22 writes the electrostatic latent image Z on the charged photoconductor 20, and the developing device 30 is charged with the electrostatic device. The latent image Z is visualized as a toner image. Thereafter, the toner image on the photoconductor 20 is conveyed to a transfer site, and the transfer device 24 electrostatically transfers the toner image on the photoconductor 20 to a recording paper 28 that is a transfer target. The residual toner on the photoconductor 20 is cleaned by the cleaning device 25. Thereafter, the toner image on the recording paper 28 is fixed by a fixing device (not shown) to obtain an image.

In the image forming apparatus of the present embodiment, since the developer of the present embodiment is used as the developer, after image formation is repeatedly performed, compared to the case where the developer of the present embodiment is not used. Even if it exists, it is thought that the brightness of the image before repeated image formation is maintained.
In addition, the use of the developer of this embodiment reduces the mechanical load on the toner compared to the case where the developer of this embodiment is not used, and the pigment contained in the toner is exposed to the outside of the toner. It is thought that it is suppressed that it falls off from toner. For this reason, in the image forming apparatus using the developer in this embodiment, even when the image formation speed is improved and the image is repeatedly formed, the repeated image formation is performed as before the image formation speed is improved. It is thought that the brightness of the previous image is maintained.

<Process cartridge, toner cartridge>
FIG. 3 is a schematic configuration diagram illustrating an example of a process cartridge according to the present embodiment. The process cartridge according to the present embodiment is characterized in that the toner according to the present embodiment described above is accommodated, and a toner holder that holds and conveys the toner is provided.

  A process cartridge 200 shown in FIG. 3 includes a photosensitive member 107 as an image carrier, a charging device 108, a developing device 111 that accommodates the toner according to the above-described embodiment, a cleaning device 113, an opening 118 for exposure, In addition, an opening 117 for static elimination exposure is combined and integrated using a mounting rail 116. 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 constitutes.

  The process cartridge 200 shown in FIG. 3 includes a charging device 108, a developing device 111, a cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. May be combined. In addition to the developing device 111, the process cartridge according to the present embodiment includes a photosensitive member 107, a charging device 108, a cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. At least one selected from the group.

  Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment is detachably attached to the image forming apparatus, and at least the toner cartridge that stores toner to be supplied to the developing unit provided in the image forming apparatus is described above. The toner according to the present exemplary embodiment is characterized. Note that the toner cartridge according to the present embodiment only needs to contain at least toner, and may contain developer, for example, depending on the mechanism of the image forming apparatus.

  The image forming apparatus shown in FIG. 2 is an image forming apparatus having a configuration in which a toner cartridge (not shown) can be freely attached and detached, and the developing device 30 is connected to the toner cartridge by a toner supply pipe (not shown). . Further, when the amount of toner stored in the toner cartridge is low, this toner cartridge may be replaced.

Hereinafter, although an example and a comparative example are given and this embodiment is described more concretely, the present invention is not limited to the following examples. Unless otherwise specified, “part” and “%” are based on mass.
In the following examples, when the cross section in the thickness direction of the toner is observed, the angle between the major axis direction in the cross section of the toner and the major axis direction of the pigment particles among all the observed pigment particles Example 12 in which the number of pigment particles in the range of −30 ° to + 30 ° is not 60% or more corresponds to the reference example.

-Preparation of toner-
[Preparation of Bright Toner 1]
<Synthesis of binder resin>
Bisphenol A ethylene oxide adduct: 216 parts Ethylene glycol: 38 parts Tetrabutoxy titanate (catalyst): 0.037 parts
The above components are placed in a heat-dried two-necked flask, and nitrogen gas is introduced into the container and heated while stirring in an inert atmosphere, and then subjected to a copolycondensation reaction at 160 ° C. for 7 hours, and then gradually up to 10 Torr. The temperature was raised to 220 ° C. while reducing the pressure to 4 hours. Once the pressure was returned to normal pressure, 9 parts of trimellitic anhydride was added, the pressure was gradually reduced to 10 Torr, and maintained at 220 ° C. for 1 hour to synthesize a binder resin.

<Preparation of resin particle dispersion>
-Binder resin: 160 parts-Ethyl acetate: 233 parts-Sodium hydroxide aqueous solution (0.3N): 0.1 parts

  The above components were put into a 1000 ml separable flask, heated at 70 ° C., and stirred by a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) to prepare a resin mixture. While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added, phase-inversion emulsified, and the solvent was removed to obtain a resin particle dispersion (solid content concentration: 30%).

<Preparation of release agent dispersion>
Carnauba wax (Toa Kasei Co., Ltd., RC-160): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1.0 parts Ion-exchanged water: 200 parts The above was mixed and heated to 95 ° C. and dispersed using a homogenizer (Ultra Turrax T50, manufactured by IKA), and then dispersed for 360 minutes with a Manton Gorin high-pressure homogenizer (Gorin) to obtain a volume average particle size. A release agent dispersion (solid content concentration: 20%) prepared by dispersing release agent particles having a diameter of 0.23 μm was prepared.

<Preparation of glitter pigment particle dispersion>
Aluminum pigment (Showa Aluminum Powder Co., Ltd., 2173EA): 100 parts Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen R): 1.5 parts Ion-exchanged water: 900 parts From aluminum pigment paste After removing the solvent, the above is mixed, and dispersed for about 1 hour using an emulsifying and dispersing machine Cavitron (manufactured by Taiheiyo Kiko Co., Ltd., CR1010) to disperse glitter pigment particles (aluminum pigment). A dispersion (solid content concentration: 10%) was prepared.

<Production of toner>
-Resin particle dispersion: 450 parts-Release agent dispersion: 50 parts-Bright pigment particle dispersion: 21.74 parts-Nonionic surfactant (IGEPAL CA897): 1.40 parts The mixture was placed in a stainless steel container and dispersed and mixed for 10 minutes while applying a shearing force at 4000 rpm with a homogenizer (manufactured by IKA, Ultra Lalux T50). Next, 1.75 parts of a 10% nitric acid aqueous solution of polyaluminum chloride as a flocculant was gradually added dropwise, and the homogenizer was rotated at 5000 rpm for 15 minutes and mixed to obtain a raw material dispersion.
Thereafter, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle stirring blades for forming a laminar flow, and a thermometer, and started to be heated with a mantle heater at a stirring speed of 810 rpm. The growth of aggregated particles was promoted at 54 ° C. At this time, the pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 with 0.3N nitric acid or 1N sodium hydroxide aqueous solution. The agglomerated particles were formed by maintaining the above pH range for about 2 hours. At this time, the volume average particle diameter of the aggregated particles measured using Multisizer II (aperture diameter: 50 μm, manufactured by Beckman-Coulter) was 10.4 μm.
Next, 100 parts of a resin particle dispersion was additionally added, and the resin particles of the binder resin were adhered to the surface of the aggregated particles. The temperature was further raised to 56 ° C., and aggregated particles were prepared while confirming the size and form of the particles with an optical microscope and Multisizer II. Thereafter, the pH was raised to 8.0 in order to fuse the aggregated particles, and then the temperature was raised to 67.5 ° C. After confirming that the aggregated particles were fused with an optical microscope, the pH was lowered to 6.0 while maintaining the temperature at 67.5 ° C., and the heating was stopped after 1 hour, followed by cooling at a rate of temperature decrease of 1.0 ° C./min. Thereafter, the mixture was sieved with a 20 μm mesh, washed repeatedly with water, and then dried with a vacuum dryer to obtain toner particles. The obtained toner particles had a volume average particle diameter of 12.2 μm.

With respect to 100 parts by mass of the obtained toner particles, 1.5 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) and 1.0 part by mass of hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805) Using a sample mill, mixing blending was performed at 10,000 rpm for 30 seconds. Thereafter, the toner 1 (brilliant toner 1) was prepared by sieving with a vibrating sieve having an opening of 45 μm. At this time, the volume average particle diameter of the aggregated particles measured using Multisizer II (aperture diameter: 50 μm, manufactured by Beckman-Coulter) was 10.4 μm. The A / B ratio was 61.

[Production of Bright Toners 2 to 22 and Comparative Toner 1]
A toner was prepared by the method described in the glitter toner 1 except that the glitter toner 1 described above was changed as follows.

  In the glossy toner 2, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 520 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 80 ° C. The A / B ratio was adjusted to 3 by changing to ° C.

  In the glossy toner 3, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 640 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 76. By adjusting the temperature to 5 ° C., the A / B ratio was adjusted to 19 as described above.

  In the glossy toner 4, in the production of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 660 rpm, and the temperature in the step of fusing the aggregated particles is 67.5 ° C. to 74 The A / B ratio was adjusted to 22 by changing the temperature to ° C.

  In the glittering toner 5, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 750 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 70. By changing the temperature to 5 ° C., the A / B ratio was adjusted to 38.

  In the glossy toner 6, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 770 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 69. By changing to ° C., the A / B ratio was adjusted to 43.

  In the glittering toner 7, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 860 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 66. By adjusting the temperature to 5 ° C., the A / B ratio was adjusted to 79.

In the glittering toner 8, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 910 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 64. By adjusting the temperature to 5 ° C., the A / B ratio was adjusted to 82.

In the glossy toner 9, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 1020 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 63 By changing to 0 ° C., the A / B ratio was adjusted to 87.

In the glossy toner 10, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 1170 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 62. By changing to ° C., the A / B ratio was adjusted to 91.

In the glossy toner 11, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 1400 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 61 ° C. By changing to 0 ° C., the A / B ratio was adjusted to 98.

In the glossy toner 12, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 1540 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 81. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 13, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 1390 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 79. By changing the temperature to 5 ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 14, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 1170 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 76. By changing the temperature to 5 ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 15, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 1020 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 74. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 16, in the production of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 910 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 70. By changing the temperature to 5 ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glittering toner 17, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 860 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 69. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 18, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 770 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 66. By changing the temperature to 5 ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glittering toner 19, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 750 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 64. By changing the temperature to 5 ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glittering toner 20, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 660 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 63. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 21, in the production of the toner 1, the stirring rotation speed in the step of promoting the growth of the aggregated particles is changed from 810 rpm to 640 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 62. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

In the glossy toner 22, in the preparation of the toner 1, the stirring rotation speed in the step of promoting the growth of aggregated particles is changed from 810 rpm to 520 rpm, and the temperature in the step of fusing the aggregated particles is changed from 67.5 ° C. to 61. By changing to ° C., the A / B ratio 61 and the C / D ratio were adjusted to the values shown in Table 1.

  In the comparative toner 1, in the preparation of the toner 1, the step of accelerating the growth of the aggregated particles is changed from the two-paddle to the four-paddle, the stirring rotation speed is changed from 810 rpm to 500 rpm, and the aggregated particles are fused. The A / B ratio was adjusted to 1.8 by changing the temperature of 67.5 ° C. to 90 ° C.

[Measurement]
“Ratio (A / B)”, “Ratio of average maximum thickness C of toner to average equivalent circle diameter D (C / D)”, “observed when observing cross section in thickness direction of toner” Among all the pigment particles, the number of pigment particles in which the angle between the major axis direction of the cross section of the toner and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° (hereinafter, simply “pigment particles in the range of ± 30 °”). ”)” Was measured by the method described above. The results are shown in Table 1 below. The “brilliant toner” is simply referred to as “toner” in Table 1.

―Creation of carrier―

[Production of Carrier 1]
(Production of core)
Phenol 40 parts by mass, formalin 60 parts by mass, magnetite ((spherical magnetite particle powder having a volume average particle diameter of 0.25 μm (manufactured by Toda Kogyo Co., Ltd., magnetization value 64 emu / g (1 kOe), 1 mass% KBM403 treated product) 500 parts by mass) Then, 12 parts by mass of ammonia water and 60 parts by mass of ion-exchanged water were added, and while stirring, the temperature was gradually raised to 85 ° C., reacted and cured for 5 hours, cooled, filtered, washed, dried, and volume-averaged particles A spherical core 1 having a diameter of 36 μm was obtained.

(Preparation of carrier 1)
Into a vacuum degassing type kneader, 100 parts by mass of the core 1 adjusted as described above was added, and further 10 parts by mass of the following first resin film forming solution A1 was added and heated / depressurized to 60 ° C./−200 mmHg, After stirring for 15 minutes, the temperature was further raised / depressurized to 90 ° C./−720 mmHg, stirred and dried for 30 minutes, returned to atmospheric pressure, heated to 180 ° C., and stirred for 30 minutes. As a result, primary coated carrier particles 1 having a resin film 1 were obtained.

  When the coverage of the primary coated carrier particle 1 was measured by performing XPS measurement, the coverage of the core 1 with the first resin film was 97%. Further, the average film thickness of the first resin film in the primary coated carrier particle 1 was measured by observing the cross section of the primary coated carrier particle 1 by TEM measurement, and found to be 1.0 μm.

Next, the entire amount of the following second resin film forming solution B1 and the primary coated carrier particles 1 were put into a vacuum degassing kneader, and the temperature was kept at 60 ° C. and stirred for 10 minutes, and then the pressure was reduced to −720 mmHg. Then, toluene was distilled off to obtain a carrier 1 formed on the core 1 in the order of the first resin film and the second resin film.

The obtained carrier 1 had a volume average particle diameter of 39 μm.
Further, when the coverage of the carrier 1 was measured by performing XPS measurement, the coverage of the core 1 with the second resin film was 97%. Moreover, about this carrier 1, when the average film thickness of the 2nd resin film in the carrier 1 was measured by performing TEM observation, it was 0.5 micrometer.

<First Resin Film Forming Solution A1>
-Toluene 150 parts by mass-Methyl ethyl ketone 150 parts by mass-Bisphenol A type epoxy resin (EP-4100, manufactured by Adeka) 15 parts by mass-Amino-based curing agent (Adeka Hardener EH4602, manufactured by Adeka) 1.5 parts by mass The solution A1 for forming the first resin film was prepared.

<Second solution B1 for forming a resin film>
-Toluene 100 parts by mass-Styrene-methacrylate copolymer (component ratio 30:70) 2.4 parts by mass-Carbon black (Regal 330; manufactured by Cabot) 0.4 part by mass The above components and glass beads (particle size 1 mm, toluene and The same amount) was put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a second resin film forming solution B1.

[Preparation of Carriers 2-7 and Comparative Carriers 1-3]
A carrier was prepared by the method described in Carrier 1 except that the carrier 1 described above was changed as follows.

(Preparation of carrier 2)
The carrier 2 is the same as the carrier 1 except that the first resin film-forming solution A1 was increased from 10 parts by mass to 20 parts by mass so that only the first film thickness was increased. In the same manner as in Example 1, Carrier 2 was obtained.

(Preparation of carrier 3)
In carrier 3, in the preparation of carrier 1, the styrene-methacrylate copolymer of solution B1 for forming the second resin film is changed from 2.4 parts by mass to 3.6 parts by mass, and carbon black is 0.4 parts by mass. The carrier 3 was obtained in the same manner as the carrier 1 except that the amount was increased from 0.6 part to 0.6 parts by weight and the thickness was adjusted so that only the second film thickness was increased.

(Preparation of carrier 4)
In the carrier 4, in the production of the carrier 1, 1.0 part by mass of acicular titanium oxide (manufactured by Ishihara Sangyo Co., Ltd .: TTO-V3) was used instead of carbon black in the second resin film forming solution B1. Otherwise, Carrier 4 was obtained in the same manner as Carrier 1.

(Preparation of carrier 5)
In carrier 5, 100 parts by mass of epoxy resin solid (4010P, Mitsubishi Chemical bisphenol A type epoxy resin), 10 parts by mass of adipic acid dihydrazide curing agent, magnetite ((spherical magnetite particle powder having a volume average particle diameter of 0.25 μm) (Toda Kogyo Co., Ltd., magnetization value 64 emu / g (1 kOe), 1% by weight KBM403 treated product) 300 parts by weight of the blend was dry blended (Henschel mixer), melt mixed and dispersed (biaxial extruder kneader) After cooling, coarse pulverization, fine pulverization (jet mill), classification with an air classifier to obtain epoxy resin particles, a spherical core 5 is obtained by spheronization treatment with a hybridization system (manufactured by Nara Machinery Co., Ltd.). It was.

  The above core 5 is used instead of the core 1 used in the production of the carrier 1, the following solution A5 is used instead of the solution A1 used in the production of the carrier 1, and the following solution A1 is used instead of the solution B1 used in the production of the carrier 1. A carrier 5 was obtained by sequentially forming a first resin film and a second resin film on the core 5 under the same conditions and the same manufacturing method as the carrier 1 except that the solution B5 was used.

<Solution A5 for Forming First Resin Film for Carrier 5>
-Toluene 100 parts by mass-Styrene-methacrylate copolymer (component ratio 70:30) 4.2 parts by mass The above components and glass beads (particle size 1 mm, equivalent to toluene) are put into a sand mill manufactured by Kansai Paint Co., Ltd. The mixture was stirred at 1200 rpm for 30 minutes to prepare a second resin film forming solution A5.

<Solution B5 for forming second resin film for carrier 5>
-Toluene 100 parts by mass-Perfluorooctyl methacrylate-Methyl methacrylate copolymer (copolymerization molar ratio 20/80) 5 parts by mass,
Carbon black (Regal 330; manufactured by Cabot Corporation) 0.4 parts by mass The above components and glass beads (particle size 1 mm, equivalent to toluene) were put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred for 30 minutes at a rotation speed of 1200 rpm. A solution B5 for forming a resin film was prepared.

(Preparation of carrier 6)
In the carrier 6, when the core 1 for the carrier 1 is manufactured, the core of the melamine resin is synthesized, the styrene acrylic resin is used for forming the first resin film, and the silicone resin is used for forming the second resin film. To get carrier 6.

  Specifically, the following core 6 is used in place of the core 1 used in the production of the carrier 1, the following solution A6 is used in place of the solution A1 used in the production of the carrier 1, and the solution B1 used in the production of the carrier 1 is used. A carrier 6 was obtained by sequentially forming a first resin film and a second resin film on the core 6 under the same conditions and the same manufacturing method as the carrier 1 except that the following solution B6 was used instead of the following.

<Production of core 6>
40 parts by mass of formalin, 31 parts by mass of melamine, 500 parts by mass of magnetite used in the core 1, 12 parts by mass of ammonia water and 60 parts by mass of ion-exchanged water were added, and the water temperature was raised to 85 ° C. while stirring to form methylol (primary Reaction) (reaction time: 1 hour). Thereafter, formic acid was added to adjust the pH to 7, followed by condensation reaction (secondary reaction) at 85 ° C. for 5 hours, cooling, filtration, washing and drying to obtain a spherical core 6.

<Solution A6 for Forming First Resin Film for Carrier 6>
-Toluene 100 parts by mass-Styrene-methacrylate copolymer (component ratio 70:30) 3.0 parts by mass-Carbon black (Regal 330; manufactured by Cabot Corporation) 1.2 parts by mass The above components and glass beads (particle size 1 mm, toluene and The same amount) was put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a second resin film forming solution A6.

<Solution B6 for Second Resin Film Formation for Carrier 6>
-Toluene 183 parts by mass-Silicone resin solution 113 parts by mass (solid content 23% by mass (SR2410: manufactured by Toray Dow Corning Silicone)
Carbon black 0.4 parts by weight The above components and glass beads (particle size 1 mm, equivalent to toluene) are placed in a sand mill manufactured by Kansai Paint Co., Ltd., and stirred for 30 minutes at a rotational speed of 1200 rpm to form a second resin film forming solution B6 was adjusted.

(Preparation of carrier 7)
Carrier 7 was prepared under the same conditions as carrier 1 except that ferrite (DOWA Sr ferrite average particle size 1.40 μ NF350 coercive force 123 Oe) was used instead of magnetite in core 1 used in carrier 1. did.

(Adjustment of comparative carrier 1)
In the comparative carrier 1, in the production of the carrier 1, a core was obtained by additionally using 1.2 parts by mass of carbon black (Regal 330; manufactured by Cabot) during the production of the core. The resin films 1 and 2 were obtained without being formed.

(Adjustment of comparative carrier 2)
In the comparative carrier 2, 1.2 parts by mass of carbon black (Regal 330; manufactured by Cabot) was further added at the time of adjusting the solution A 1 for forming the first resin film used in the preparation of the carrier 1. A comparative solution A2 for forming a resin film 1 was obtained.
Then, in place of the first resin film forming solution A1 used in the preparation of the carrier 1, the comparative carrier 2 was used under the same conditions as the carrier 1 except that the first resin film forming solution A2 was used. Produced.

(Adjustment of comparative carrier 3)
As the comparative carrier 3, the comparative carrier 3 was produced under the same conditions as the carrier 1 except that the second resin film was not formed in the carrier 1.

[Examples 1 to 28, Comparative Examples 1 to 13]
100 parts by mass of the carrier or comparative carrier produced above and 7 parts by mass of the toner or comparative toner produced above were mixed in the combinations shown in Table 3 and mixed at 40 rpm for 20 minutes in a V blender. A developer was obtained.

〔Evaluation test〕
-Evaluation of maintenance of glitter-
Using each of the developers shown in Table 3 below, a solid image was formed under the following conditions using the following image forming apparatus.
Specifically, a solid image was formed by the following method.
The developer used as a sample is charged in a developing device of DocuCentre-III C7600 manufactured by Fuji Xerox Co., Ltd., and on a recording paper (OK top coat + paper, manufactured by Oji Paper Co., Ltd.), a fixing temperature of 190 ° C., A solid image with a toner loading of 4.5 g / cm ² was formed at a fixing pressure of 4.0 kg / cm ² .
With respect to the obtained solid image (first solid image), it conforms to JIS K5600-4-3-3: 1999 “General Test Method for Paints—Part 4: Visual Characteristics of Coating Film—Section 3: Visual Comparison of Colors” The brightness was visually evaluated under a color observation illumination (natural daylight illumination). In addition, evaluation evaluated particle feeling (effect of glittering glitter) and optical effect (change in hue depending on viewing angle), and classified into the following stages (glossiness level). Two or more are actually usable levels.

5: Particle feeling and optical effect are harmonized.
4: Slight particle feeling and optical effects.
3: Normal sensation 2: Blurred feeling 1: No particle feeling or optical effect.

  As described above, after evaluating the glitter for the first solid image, a running test for continuously forming 100,000 images at a process speed of 400 mm / s is performed, and the glitter evaluation is performed again. went. Then, the first solid image and the solid image formed after forming 100,000 images at a process speed of 400 mm / s are compared with the evaluation results of the glitter, and according to the following evaluation criteria: The maintenance of glitter was evaluated. The evaluation results are shown in Table 3.

Evaluation criteria for maintaining brilliancy: A: No deterioration in brilliant level, very good.
○: A slight decrease in brightness level (Δ level 1) is good.
◯-: Although the brightness level was lowered (Δ level 2), there was no problem.
Δ: The glitter level is lowered (Δ level 2), and the lowered level is also acceptable in actual use.
X: The brightness level is significantly reduced (Δ level 3), but the level after reduction is less than the allowable range (level 1) even when the level is small (Δ level 2 or less)

  The process speed represents the print speed. For example, in the case of 350 mm / s, it corresponds to 100 sheets of A4 (width 210 mm) per minute.

  Next, for the image forming apparatus, the maintenance of glitter was evaluated in the same manner as described above except that the process speed was 600 mm / s. The evaluation results are shown in Table 3.

2 toner, 4 pigment particles, 20, 107 photoconductor, 21, 108 charging device, 22 exposure device, 24 transfer device, 30 developing device, 40 toner, 111 developing device, 112 transfer device, 113 cleaning device, 115 fixing device, 200 process cartridge

Claims (7)

Of all the pigment particles that contain scale-like pigment particles, have an average equivalent circle diameter D longer than the average maximum thickness C, and are observed when a cross section in the thickness direction is observed, the cross section The number of pigment particles in which the angle between the major axis direction and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is 60% or more of all the observed content particles, and a solid image is formed. In this case, the reflectance A at the light reception angle + 30 ° and the reflectance B at the light reception angle −30 °, which are measured when the incident angle light of −45 ° is irradiated to the image by the goniophotometer, A toner having a ratio (A / B) of 2 or more and 100 or less;
On a core containing magnetic powder and resin, a carrier having a first resin film and a conductive second resin film in this order;
A developer containing The developer according to claim 1, wherein an average film thickness of the first resin film in the carrier is equal to or greater than an average film thickness of the second resin film. 3. The developer according to claim 2, wherein an average film thickness of the first resin film is in a range of 2 to 10 times when the average film thickness of the second resin film is 1. According to any one of claims 1 to 3 ratio of the average circle equivalent diameter D and the average maximum thickness C in the toner (C / D) is in the range of 0.001 to 0.500 or less Developer. A toner cartridge containing the developer according to any one of claims 1 to 4 . At least one of an image carrier, a charging device for charging a member to be charged, a latent image forming device for forming an electrostatic latent image on the member to be formed, and a transfer device for transferring a toner image to a recording member;
A developing device that develops an electrostatic latent image as a toner image with toner contained in the developer according to any one of claims 1 to 4 ,
Process cartridge with An image carrier,
A charging device for charging the image carrier;
A latent image forming apparatus for forming an electrostatic latent image on the image carrier;
A developing device for developing as a toner image by a toner contained in the developer according to the electrostatic latent image to claims 1 to 4,
A transfer device for transferring the toner image formed on the image carrier to a recording medium;
An image forming apparatus.

Images