JP2016153837A - Electrostatic charge image developer, developer cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developer that suppresses the occurrence of image unevenness even when the process speed of a system is changed.SOLUTION: There is provided an electrostatic charge image developer including a toner for electrostatic charge image development containing toner base particles and a carrier, where the number average ratio of a minor axis b to a major axis a (b/a) on a cross section of the toner base particle is 0.1 to 0.7; the fluidity of the carrier is 24 to 28 seconds/50 g. The carrier includes ferrite particles, and the fluidity of the ferrite particles is preferably 26 to 29 seconds/50 g.SELECTED DRAWING: Figure 2

Description

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

A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image (electrostatic latent image) is formed on a photoreceptor (image carrier) by charging and exposure processes, the electrostatic latent image is developed with a developer containing toner, and a transfer and fixing process. It is visualized through.
In recent years, there is an increasing demand for forming an image on a recording medium different from conventional recording paper, such as printing on cardboard.
As conventional electrostatic charge image developers, those described in Patent Documents 1 to 4 are known.
In Patent Document 1, in a carrier comprising magnetic core material particles and a coating layer formed on the surface of the core material particles, the coating layer contains at least a silicone resin, and the bulk density of the core material particles The particle density ratio of the core particles is 1.6 or more and 1.9 or less, and the fluidity of the carrier measured using a measuring device according to JIS-Z-2502 except that the orifice diameter is 3 mm ( A developer containing a carrier is described, wherein the second / 50 g) is from 17 to 23.
Patent Document 2 discloses a developer for developing an electrostatic latent image formed on a latent image carrier, which includes a toner including at least a colorant and a binder resin and a magnetic carrier. The toner is obtained by applying a mechanical shearing force in the liquid and deforming it, and the flatness (Dv / d) of the toner is 1.2 to 2.0 (where Dv is the volume average particle diameter of the toner, d is the average thickness when the toner is viewed from the direction in which the projected area is maximized.) The developer is characterized in that the bulk density change rate of the developer is 10% or less.
Patent Document 3 discloses a developer used in a tandem-type electrophotographic image forming process: the developer includes a toner and a carrier; the toner has a shape factor SF-1 of 120 or more and 160 or less. The average circularity is 0.98 or less and 0.93 or more, the weight average particle diameter (D4) is 3.0 or more and 8.0 μm or less, and the weight average particle diameter (D4) and the number average particle diameter ( Dn) is 1.01 or more and 1.20 or less; in the carrier, X is 1 or more and 5 mol% or less, Y is 5 or more and 55 mol% or less, and Z is 45 or more and 55 mol% or less. (MgO) _X (MnO) _y (Fe ₂ O ₃ ) _{Z is} a general spherical ferrite having an average particle diameter of 20 to 45 μm; and alumina on the surface of the ferrite. Dispersed resin A developer for an electrophotographic imaging process is described, characterized in that it is coated.
In Patent Document 4, in an electrophotographic system in which a process speed (mm / second) of an image forming apparatus is 30 or more and 300 or less, in a two-component developer containing at least a toner and a carrier, the toner is bonded. As the adhesion resin, at least a polyester resin is contained, the acid value of the polyester resin is 5 to 30 mgKOH / g, and further contains a colorant and a release agent, and the average circularity of the toner is 0.965 or more and 1. 000 or less, and the carrier is a magnetic resin having a core particle which is a magnetic material-dispersed particle composed of a binder resin and at least a magnetic metal oxide particle, and a resin coating layer provided on the surface of the magnetic carrier core particle A coated carrier, wherein the magnetic fine particle dispersed resin carrier is in a magnetic brush state under an electric field of 5,000 to 25,000 V / cm. Describes a two-component developer characterized by having a dynamic electrical resistance of 1 × 10 ⁷ to 1 × 10 ¹³ Ωcm.

JP 2008-185562 A JP 2005-266040 A JP 2005-321725 A JP 2006-184699 A

The present inventors have found that there is a problem that the image density changes with a change in process speed, particularly in a toner containing flat toner base particles.
For example, when the speed is reduced from the normal printing speed, the developer agitation is weakened in the developing machine, and the amount of charge due to frictional charging is reduced. Therefore, the development amount is increased and the image density is increased. It is estimated that unevenness occurs.

  An object of the present invention is to provide an electrostatic charge image developer in which the occurrence of image unevenness is suppressed even when the process speed of the system changes.

The above-described problems of the present invention have been solved by means described in the following <1> or <5> to <8>. It is described below together with <2> to <4> which are preferred embodiments.
<1> An electrostatic image developing toner containing toner mother particles and a carrier, wherein the number average ratio (b / a) of major axis a to minor axis b in the cross section of the toner mother particles is 0.1 to 0. The electrostatic charge image developer, wherein the carrier has a fluidity of 24 to 28 seconds / 50 g.
<2> The electrostatic charge image developer according to <1>, wherein the carrier includes ferrite particles, and the fluidity of the ferrite particles is 26 to 29 seconds / 50 g.
<3> The electrostatic charge image developer according to <2>, wherein the ferrite particles have a surface roughness Sm of 1 to 5 μm and a maximum height Ry of 0.2 to 0.7 μm.
<4> The toner according to any one of <1> to <3>, wherein the toner includes a bright pigment having a number average ratio (minor axis / major axis) of a major axis to a minor axis of 0.1 to 0.7. An electrostatic charge image developer,
<5> A developer cartridge containing the electrostatic charge image developer according to any one of <1> to <4>.
<6> A process cartridge comprising a developer holder that contains the electrostatic charge image developer according to any one of <1> to <4> and that holds and conveys the electrostatic charge image developer.
<7> Image carrier, charging unit for charging the image carrier, exposure unit for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier, and development including toner Developing means for developing the electrostatic latent image with an agent to form a toner image, transfer means for transferring the toner image from the image holding member to the surface of the transfer target, and toner transferred to the surface of the transfer target An image forming apparatus, wherein the developer is the electrostatic charge image developer according to any one of <1> to <4>.
<8> A latent image forming step for forming an electrostatic latent image on the surface of the image carrier, and development for forming the toner image by developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner. And a fixing step for fixing the toner image transferred to the surface of the transfer medium, wherein <1> to <4> are used as the developer. An image forming method using the electrostatic charge image developer according to any one of the above.

According to the invention described in <1>, there is provided an electrostatic charge image developer in which occurrence of image unevenness is suppressed even when the process speed is changed as compared with the case where the present configuration is not provided. Is done.
According to the invention described in <2>, even when the flow rate of the ferrite particles contained in the carrier is less than 26 seconds / 50 g, or when the process speed is changed as compared with the case where it exceeds 29 seconds / 50 g. Thus, it is possible to provide an electrostatic image developer capable of providing an image in which the occurrence of image unevenness is further suppressed.
According to the invention described in <3>, the process speed is changed as compared with the case where the surface roughness and / or the maximum height of the ferrite particles contained in the carrier do not satisfy the numerical range described in <3>. Even in this case, it is possible to provide an electrostatic charge image developer capable of providing an image in which the occurrence of image unevenness is further suppressed.
According to the invention described in <4>, an electrostatic charge image developer capable of providing an image in which occurrence of image unevenness is further suppressed even when the process speed is changed as compared with the case where the present configuration is not provided. Can be provided.
According to the invention described in <5>, there is provided a developer cartridge in which occurrence of image unevenness is suppressed even when the process speed is changed as compared with the case where the present configuration is not provided. .
According to the invention described in <6>, there is provided a process cartridge in which occurrence of image unevenness is suppressed even when the process speed is changed as compared with the case where the present configuration is not provided.
According to the invention described in <7>, there is provided an image forming apparatus in which occurrence of image unevenness is suppressed even when the process speed is changed as compared with the case where the present configuration is not provided. .
According to the invention described in <8>, there is provided an image forming method in which occurrence of image unevenness is suppressed even when the process speed is changed as compared with the case where the present configuration is not provided. .

It is a schematic diagram showing an example of a cross-sectional shape of the glitter toner suitable for the present embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge of this embodiment.

Hereinafter, the present embodiment will be described.
In the present embodiment, the description “A to B” represents not only a range between A and B but also a range including A and B at both ends thereof. For example, if “A to B” is a numerical value range, “A or more and B or less” or “B or more and A or less” is represented.
In the present embodiment, “(meth) acryl” is an expression including both “acryl” and “methacryl”.
In the present embodiment, a combination of two or more preferred embodiments is a more preferred embodiment.

(Electrostatic image developer)
The electrostatic charge image developer according to the exemplary embodiment includes a toner for developing an electrostatic charge image containing toner mother particles and a carrier, and has a number average ratio (b / a) is 0.1 to 0.7, and the fluidity of the carrier is 24 to 28 seconds / 50 g.

The inventors have found that the electrostatic image developer in the present embodiment can provide an image with less unevenness even when the process speed is changed.
Although the detailed mechanism is unknown, the carrier used in the present embodiment is the case where the process speed is changed by combining the moderately fluid carrier used in the present embodiment and the proper flatness toner. However, it is presumed that an image in which occurrence of image unevenness is suppressed can be provided because a preferable charge amount is reached early.

The toner may contain an external additive as a fluidizing agent on the surface of the toner base particles.
As described later, the external additive can be separated from the toner base particles by subjecting the toner to ultrasonic treatment in an aqueous surfactant solution.
Hereinafter, the electrostatic charge image developing carrier and the toner will be described in detail in this order.

<Carrier for developing electrostatic image>
The fluidity of the electrostatic image developing carrier (hereinafter also simply referred to as “carrier”) in the present embodiment is 24 to 28 seconds / 50 g, and preferably 26 to 27 seconds / 50 g.
When the fluidity of the carrier is in the above range, the friction and electric resistance between the toner and the carrier is sufficiently performed, and the carrier easily flows between the toners. As a result, occurrence of image unevenness is suppressed.
The fluidity of the carrier can be measured by the method described in JIS-Z2502: 2502.
The number average particle diameter of the carrier is, for example, 15 μm or more and 50 μm or less, and may be 20 μm or more and 40 μm or less.
The number average particle diameter is measured by obtaining the maximum diameter of each particle from an electron microscope SEM photograph and obtaining the average value from 100 particle diameters of the particles.

Examples of the volume electric resistance (25 ° C.) of the carrier include a range of 1 × 10 ⁷ Ω · cm to 1 × 10 ¹⁵ Ω · cm, and 1 × 10 ⁸ Ω · cm to 1 × 10 ¹⁴ Ω · cm. It may be 1 × 10 ⁸ Ω · cm to 1 × 10 ¹³ Ω · cm.

The carrier for developing an electrostatic charge image in this embodiment preferably contains core particles and has a coating layer that covers the core particles.
For the carrier used in this embodiment, core particles having a target flow may be used as they are, but resin coating can be performed for the purpose of controlling charging and resistance.
Hereinafter, the core particle and the multilayer will be described.

[Core particles]
The core material particles are not particularly limited, and examples thereof include known particles such as magnetic particles and magnetic particle-dispersed resin particles in which magnetic particles are dispersed in a resin.

The core particles used in the present embodiment are preferably magnetic particles having a fluidity of 26 to 29 seconds / 50 g, more preferably ferrite particles having a fluidity of 26 to 29 seconds / 50 g, and a fluidity of 27 to 28 seconds. / 50 g of ferrite particles is more preferable.
When the fluidity of the magnetic particles or ferrite particles is within the above range, even when the coating resin is lost, the fluidity of the carrier is hardly deteriorated, and the friction and electric resistance between the toner and the carrier is sufficiently performed. The fluidity between the toners is maintained.
By carrying out resin coating on the core particles, the carrier particles are nearly spherical, and the carrier fluidity value is lowered. However, the shape of the magnetic particles is dominant in the fluidity, and there is a limit to the fluidity control by the resin coating. Therefore, in order to adjust the fluidity of the carrier to the range specified in the present embodiment, it is preferable to control the fluidity of the magnetic particles.

-Ferrite particles-
As the ferrite particles, ferrite particles having a structure represented by the following formula are preferable.
Formula: (MO) _X (Fe ₂ O ₃ ) _Y
In the above formula, M represents at least one selected from the group consisting of Cu, Zn, Fe, Mg, Mn, Ca, Li, Ti, Ni, Sn, Sr, Al, Ba, Co, and Mo. X and Y represent molar ratios, and X + Y = 100.
Examples of ferrite having a structure represented by the above formula include, for example, manganese-zinc based ferrite, nickel-zinc based ferrite, manganese-magnesium based ferrite, copper-zinc based ferrite, etc. Can be mentioned.
As a ferrite particle used for this embodiment, manganese ferrite is mentioned preferably. Manganese ferrite contains at least Fe and Mn as metals and has a good balance between magnetization and resistance. Manganese ferrite may also contain metals other than Fe and Mn. Examples thereof include Mn—Mg based ferrite containing Mn and Mg, and Mn—Zn based ferrite containing Mn and Zn.

-Ferrite particle manufacturing method-
Although the manufacturing method of a ferrite particle is not specifically limited, For example, you may manufacture by passing through the following process.
An appropriate amount of each material constituting the ferrite is blended and pulverized using a bead mill or the like, and then heated to obtain an oxide (temporary firing). Next, an appropriate amount of a binder, a binder resin such as polyvinyl alcohol is blended with the oxide, and pulverized / mixed with a wet ball mill or the like. During pulverization / mixing, 0.2 to 1.0% by mass of titanium oxide is added to the total mass of the mixture as necessary. Next, granulation and drying are performed with a spray dryer or the like to produce particles before firing. The final particle size is determined by the particle size at this time. Then, after firing, it may be pulverized and further classified into a desired particle size distribution to obtain ferrite particles. In firing, it is preferable to lower the oxygen partial pressure, and it is also preferable to perform heating in the atmosphere (post-adjustment) in order to adjust the surface after firing.
These manufacturing conditions differ depending on the additive material. Therefore, target ferrite particles are produced by a combination of the composition of the additive material and the manufacturing conditions.
Below, an example of the manufacturing method of the ferrite particle (henceforth "specific ferrite particle") whose fluidity | liquidity preferably used in this embodiment is 26-29 second / 50g is demonstrated. In addition, as for the manufacturing method of the said ferrite particle, the material described below is not limited to a numerical value.

In order to adjust the fluidity to 26 to 29 seconds / 50 g, it is preferable that irregularities of agglomerates exist on the surface while making the shape close to a sphere. According to the conventional method, if irregularities are left on the surface, the surface is deformed. If spherical, irregularities do not remain on the surface, and it is difficult to adjust the fluidity to the above range while the irregularities exist.
The present inventors have found that the desired particles can be obtained by leaving the agglomerate interface with the additive while making the ferrite particles spherical by setting the firing conditions appropriately.
After mixing iron oxide, magnesium hydroxide, and manganese oxide so that the molar ratio of metal is about 2: 0.2: 0.8, 0.5 wt% of titanium oxide is added and mixed. Temporary baking is performed at a temperature of 800 to 850 ° C. Next, the mixture is pulverized and mixed with glass beads together with the pre-baked product, water, polycarboxylic acid, and polyvinyl alcohol. When the dispersion diameter reaches 1.5 μm, the particle size is increased to 38 μm with a spray dryer and dried. This dried product is fired at 1,400 to 1,500 ° C. and an oxygen partial pressure of 2% for 5 hours, and is subjected to crushing, magnetic sorting and classification to obtain 35 μm magnetic particles. Furthermore, the specific ferrite particle which has an unevenness | corrugation in the surface is obtained by performing additional heating for 4 hours at the temperature of 800-900 degreeC.
Conventionally, in order to spheroidize particles, a method has been used in which ferrite is promoted by raising the firing temperature or lowering the oxygen concentration during firing. However, in this method, the surface is not uneven, and the surface is smoothed. This time, by increasing the firing temperature and increasing the oxygen concentration, the spheroidization is proceeding while leaving the crystal grain boundaries and leaving the irregularities. Further, by adding TiO _2, TiO ₂ is present in the grain boundary, preventing the growth of the particle size of the particle diameter surface. Furthermore, by adding heating, it becomes possible to form a sphere while leaving surface irregularities, which has been difficult in the past.

By adding titanium oxide, the surface irregularities of the specific ferrite particles are adjusted. The surface irregularities can be expressed using the surface roughness Sm and the maximum height Ry. The surface roughness Sm (average interval between surface irregularities) of the ferrite particles used in the present embodiment is preferably 1 μm to 5 μm, and more preferably 2 μm to 4 μm.
The maximum height Ry of the ferrite particles is preferably 0.2 μm to 0.7 μm, more preferably 0.3 μm to 0.5 μm, and further preferably 0.3 μm to 0.4 μm. preferable.
The surface roughness Sm and the maximum height Ry are values measured according to JIS B 0601-1994.
Specifically, the surface roughness Sm and the maximum height Ry were measured at a magnification of 3,000 using an ultra-deep color 3D shape measurement microscope (VK-9500, manufactured by Keyence Corporation) for 50 carriers. Determine by observing the surface. For the maximum height Ry, a roughness curve is obtained, and a reference length is extracted in the direction of the average line. The height Yp from the average line of the extracted part to the highest peak and the depth Yv to the lowest valley The maximum height Ry is obtained by obtaining the sum (Yp + Yv). The reference length for obtaining the maximum height Ry is 10 μm, and the cutoff value is 0.08 mm.
The surface roughness Sm (average interval between irregularities) is an average value of intervals of one mountain and valley obtained from an intersection where the roughness curve is obtained and the roughness curve intersects the average line. The reference length for determining the surface roughness Sm is 10 μm, and the cutoff value is 0.08 mm.

  Here, since the specific ferrite particles having a surface roughness Sm of 1 to 5 μm leave an appropriate grain interface, the carrier and toner are easily triboelectrically charged. On the other hand, if Ry is in the range of 0.2 to 0.7, the convex portions of the ferrite particles are moderately high, the number of contact between the toner and the carrier is suitable, and as a result, charging becomes smooth and results This has the effect of further suppressing the occurrence of image unevenness.

The volume average particle diameter (D50v) of the ferrite particles used in the present embodiment is preferably 30 μm or more and 50 μm or less.
The volume average particle size of the magnetic particles and pulverized particles in the present embodiment is a value measured with a laser diffraction particle size distribution analyzer LA-700 (manufactured by Horiba, Ltd.). With respect to the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume average particle size (D50v) is defined as a particle size that becomes 50% cumulative by subtracting the volume cumulative distribution from the small particle size side.

(Coating layer)
The multi-layer includes a coating resin.
Examples of the coating resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, and alkyl. Examples thereof include (meth) acrylate resins, straight silicone resins containing an organosiloxane bond or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, and epoxy resins. Here, “(meth) acrylate” means acrylate or methacrylate.

  The coating layer preferably contains a resin having a cycloalkyl group. The resin having a cycloalkyl group includes (1) a homopolymer of a monomer containing a cycloalkyl group, (2) a copolymer obtained by polymerizing two or more monomers containing a cycloalkyl group, and (3) a cycloalkyl group. Examples thereof include a copolymer of a monomer and a monomer not containing a cycloalkyl group.

  By using a resin containing a cycloalkyl group for the coating layer, excessive charging of toner under low temperature and low humidity is suppressed, and density unevenness of the image is further suppressed.

  In the above (1) to (3), examples of the cycloalkyl group include a 3- to 10-membered cycloalkyl group, and a 3- to 8-membered (C3-C8) cycloalkyl group. Group is preferable, and a 5-membered to 6-membered (C5-6) cycloalkyl group (cyclopentyl, cyclohexyl) is more preferable from the viewpoint of stable charge on the carrier surface. If the cycloalkyl group has 8 or less carbon atoms, the steric hindrance is small and good fastness of the resin can be obtained. If the cycloalkyl group has 5 to 6 carbon atoms, it is stable as a cyclic structure. The structure of the cycloalkyl group is specified by NMR of the resin.

  The resin having a cycloalkyl group is preferably a resin containing a polymer unit derived from at least one selected from the group consisting of cycloalkyl acrylate and cycloalkyl methacrylate. Alkyl methacrylate, copolymer of cycloalkyl methacrylate and alkyl methacrylate, copolymer of cycloalkyl acrylate and alkyl methacrylate, copolymer of cycloalkyl methacrylate and alkyl acrylate, and further, cycloalkyl acrylate, cycloalkyl methacrylate, Copolymer of alkyl acrylate and alkyl methacrylate, copolymer of cycloalkyl methacrylate and styrene, cycloalkyl acrylate and Copolymers of styrene, polyester resin having a cycloalkyl group in a side chain, a urethane resin having a cycloalkyl group in a side chain, such as urea resin having a cycloalkyl group in a side chain.

  In particular, the resin having a cycloalkyl group is preferably a copolymer of the monomer (3) containing a cycloalkyl group and a monomer not containing a cycloalkyl group, and is selected from cycloalkyl acrylate and cycloalkyl methacrylate. More preferably, it is a copolymer of at least one of the above and methyl methacrylate, and a copolymer of cycloalkyl acrylate and methyl methacrylate is more preferable. When the cycloalkyl group is a copolymer of cycloalkyl acrylate and methyl methacrylate, suppression of change in charge amount is maintained. This effect is thought to be due to improved adhesion between the coating layer and the magnetic particles.

  As a copolymerization ratio (at least one of cycloalkyl acrylate and cycloalkyl methacrylate: methyl methacrylate, molar ratio) in a copolymer of at least one of cycloalkyl acrylate and cycloalkyl methacrylate and methyl methacrylate, 85:15 to 99 : 1.

Furthermore, as a weight average molecular weight (Mw) of resin which has a cycloalkyl group, 3,000 or more and 200,000 or less are mentioned.
The weight average molecular weight was measured using gel permeation chromatography (GPC). GPC uses HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation), and TSKgel, SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm) are used as columns and THF is used as an eluent. (Tetrahydrofuran) was used. As experimental conditions, the sample concentration is 0.5 mass%, the flow rate is 0.6 ml / min, the sample injection amount is 10 μl, the measurement temperature is 40 ° C., and a RI (Refractive Index) detector (differential refractive index detector) is used. The experiment was conducted using this. In addition, the calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A” -2500 "," F-4 "," F-40 "," F-128 ", and" F-700 ".

Further, in the carrier according to the present embodiment, conductive particles (volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less) may be dispersed in the coating layer. Examples of the conductive particles include metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, and tin oxide, but are not limited thereto. is not.

Further, when the electrostatic charge image developing carrier according to the present embodiment is a resin-coated carrier in which a part of the surface of the magnetic particles is coated with a resin, the carrier resistance and fluidity depend on the magnetic particles. The coverage of the magnetic particles with respect to the coating layer is preferably 70% or more and 98% or less, and more preferably 85% or more and 95% or less.
Here, the said coverage is calculated | required by measuring a coverage with the following method, for example.
As the X-ray electron spectroscopic analyzer, ESCA-9000MX manufactured by JEOL Ltd. is used, and the carrier is fixed to the sample holder and inserted into the ESCA chamber. The degree of vacuum of the chamber is set to 1 × 10 ⁻⁶ Pa or less, Mg—Kα is used as an excitation source, and the output is set to 200 W. Under the above conditions, the XPS spectra of the magnetic particles (magnetic particles) and the carrier are measured, and the coverage is calculated from the ratio of the area intensity of the Fe peak (2p3 / 2) of the detected element.
Coverage = F2 / F1 × 100
(F1: Fe area strength of magnetic particles, F2: Fe area strength of carriers)

[Method for producing carrier]
The carrier can be produced by coating a part of the surface of the core particle with a resin.
As a method of coating a part of the surface of the core particle with a resin, a resin having a cycloalkyl group and, if necessary, various additives are coated with a solution for forming a coating layer dissolved or dispersed in an appropriate solvent. A method is mentioned. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.
More specifically, a dipping method in which magnetic particles are immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the magnetic particles, and a coating layer is formed in a state where the magnetic particles are suspended by flowing air. And a kneader coater method in which magnetic particles and a coating layer forming solution are mixed in a kneader coater to remove the solvent.

<Toner for electrostatic image development>
The electrostatic image developer of this embodiment includes an electrostatic image developing toner.
The electrostatic image developing toner used in the exemplary embodiment contains toner base particles having a number average ratio (b / a) of a major axis a and a minor axis b of 0.1 to 0.7.

[Toner mother particles]
-Number average ratio (b / a) of major axis a and minor axis b in the cross section-
The number average ratio (b / a) of the major axis a and the minor axis b in the cross section of the toner base particles used in the exemplary embodiment is 0.1 to 0.7, and is 0.4 to 0.5. preferable.
If the number average ratio (b / a) of the major axis a to the minor axis b in the cross section of the toner base particle is within the above range, the friction between the toner and the carrier is sufficiently performed, and the fluidity of the toner and the carrier is excellent. For this reason, the toner has sufficient electric resistance.

The number average ratio (b / a) of the major axis a and the minor axis b in the cross section of the toner base particles used in the exemplary embodiment is measured by the following method.
First, the toner particles are embedded using a bisphenol A type liquid epoxy resin and a curing agent, and then a cutting sample is prepared. Next, the cutting sample is cut at −100 ° C. using a cutting machine using a diamond knife, for example, LEICA ultramicrotome (manufactured by Hitachi High-Technologies Corporation) to prepare an observation sample. The observation sample is observed with a TEM at a magnification of about 5,000 times.
The cross section of 500 toner particles is observed, and the ratio (b / a) between the major axis a and minor axis b of each toner particle is determined. Here, when the cross section of the toner particle is observed, for example, as shown in FIG. 1, the maximum length is the major axis a, and the portion that protrudes most vertically in the direction orthogonal to the major axis a (thickness direction) is used as a reference. The distance between the parallel lines is the minor axis b. For example, if the cross section is in the thickness direction of the toner particles, the thickness direction is the minor axis b. The ratio (b / a) between the major axis a and the minor axis b is determined for each toner particle, and the number average value thereof is calculated.

−Number average circularity of toner particle cross section−
The number average circularity in the cross section of the toner base particles is preferably 0.50 to 0.90, more preferably 0.70 to 0.85, and still more preferably 0.60 to 0.80. When the number average circularity is within the above range, a non-electrostatic adhesion force is appropriate between the toner particles and a member such as an intermediate transfer member, and the transfer efficiency improves the transfer efficiency.

In the same manner as when the number average ratio (b / a) of the major axis a and minor axis b in the cross section of the toner base particle is obtained, the cross section of the toner particle is observed with a TEM at a magnification of about 5,000 times. Calculate the length. Further, the area of the toner particle cross section is calculated, a circle having the same area as the area is assumed, and the circumference of the circle is calculated (circumferential length of the circle obtained from the equivalent circle diameter). The circularity is calculated as “circularity = circular length of circle obtained from equivalent circle diameter / perimeter of particle image”. As shown in FIG. 2, the closer the value is to 1.0, the more spherical.
In this way, the toner particle cross section is observed for 500 toner particles, the circularity of each toner particle is obtained, and the number average value (number average circularity) thereof is calculated.

-Number average maximum thickness C (μm) and number average equivalent circle diameter D (μm)-
The toner base particles in this embodiment are not spherical but have a flat shape, and the number average maximum thickness C (μm) and the number average equivalent circle diameter D (μm) (C / D) are 0.1. It is preferable that it is -0.4, and it is still more preferable that it is 0.1-0.3. The toner base particles preferably have a round or disc shape as a whole.
When the value of the ratio (C / D) is 0.1 or more, the strength of the toner is ensured, the breakage due to stress during image formation is suppressed, and the charging is reduced due to the exposure of the pigment. Generated fog is suppressed. On the other hand, when the toner base particles contain a glitter pigment, which will be described later, excellent glitter can be obtained when the toner base particle is 0.5 or less.

The number average maximum thickness C (μm) and the number average equivalent circle diameter D (μm) are measured by the following methods.
The toner base particles are placed on a smooth surface, and are vibrated and dispersed so that there is no unevenness. With respect to 100 toners, the maximum thickness and the equivalent circle diameter of the projection surface were measured with a color laser microscope “VK-9700” (manufactured by Keyence Co., Ltd.), and the number average value thereof was measured. C and D are calculated by calculating.

  The toner mother particles have a number average value of the diameters of circles having an area equal to the projected area of each mother particle, that is, the number average equivalent circle diameter D is preferably 3 μm to 30 μm, and preferably 5 μm to 20 μm. More preferably, it is particularly preferably 7 μm to 15 μm.

In order to measure the properties of the toner with respect to the mother particles, the external additive is separated from the toner mother particles by pretreatment as necessary.
As a specific separation method, for example, FPIA-3000 (manufactured by Sysmex Corporation) is used. First, 30 ml of ion exchange water is put into a 100 ml beaker, and a surfactant (Wako Pure Chemical Industries, Ltd.) is used as a dispersant. 2 drops of Contaminone), 20 mg of the toner to be measured is put in this liquid, and dispersed for 3 minutes by ultrasonic dispersion to prepare a toner dispersion for measurement. About the obtained toner dispersion A preferred example is a method of measuring the required number of measurements using a flow-type analyzer and calculating the measured value.
As another method, the toner base particles from which the external additive has been separated can be dried and used for SEM observation, particle cross-section observation, and the like.

-Pigment-
The toner base particles contained in the toner used in this embodiment preferably contain a pigment. As the pigment, a known pigment can be used without particular limitation, but it is preferable to include a bright pigment.

-Bright pigment-
The glitter pigment particles are pigment particles having glitter, and specific examples thereof include metal powders such as aluminum, brass, bronze, nickel, stainless steel and zinc, mica coated with titanium oxide and yellow iron oxide, and barium sulfate. , Layered silicate, layered aluminum silicate coated flaky inorganic crystal substrate, single crystal plate-like titanium oxide, basic carbonate, bismuth acid oxychloride, natural guanine, flaky glass powder, metal deposited There is no particular limitation as long as it has glitter, such as flaky glass powder.
Among these, from the viewpoints of cost, stability, availability, and glitter, an aluminum pigment is preferable, and a metal pigment made of a single aluminum metal is particularly preferable.
Further, the shape of the glitter pigment is preferably scaly (flat) or flat, more preferably scaly, and the glitter pigment has a number average ratio (short) of the major axis and minor axis. (Diameter / major axis) is preferably a glitter pigment having a ratio of 0.1 to 0.7, more preferably a glitter pigment having a diameter of 0.2 to 0.5.
When the toner base particles contain the glitter pigment of the above-described aspect, there is an advantage that the toner base particles are easily aligned in the major axis direction during stirring, and the carrier is easy to flow.

The number average ratio of the major axis to the minor axis of the glitter pigment can be measured by the following method.
First, a glittering pigment is embedded using a bisphenol A type liquid epoxy resin and a curing agent, and then a cutting sample is prepared. Next, the cutting sample is cut at −100 ° C. using a cutting machine using a diamond knife, for example, LEICA ultramicrotome (manufactured by Hitachi High-Technologies Corporation) to prepare an observation sample. The observation sample is observed with a TEM at a magnification of about 5,000 times.
The cross section is observed for 500 glitter pigments, and the ratio of the major axis to the minor axis (minor axis / major axis) of each glitter pigment is determined. Here, when the cross section of the glitter pigment is observed, the maximum length is the major axis, and the distance between the parallel lines based on the most projecting portion in the vertical direction (thickness direction) perpendicular to the major axis is short. Is the diameter. For example, if the cross section is in the thickness direction of the glitter pigment, the thickness direction is the minor axis. The ratio of the major axis to the minor axis (minor axis / major axis) is determined for each glittering pigment, and the number average value thereof is calculated.

The glitter pigment used in the present embodiment can be obtained by arbitrarily pulverizing, mixing, classifying, and sieving a commercially available metal pigment.
For the preparation of the glitter pigment, a known dispersion method can be used.For example, a general dispersion means such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, a dyno mill, or an optimizer can be adopted, and there is no limitation. It is not something. The colorant is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base. The volume average particle diameter of the dispersed colorant particles may be 20 μm or less, but if it is in the range of 3 μm or more and 16 μm or less, it is desirable that the dispersion of the colorant in the toner is good without impairing the cohesiveness. .
The method for measuring the volume average particle diameter of the glitter pigment is as follows. First, a bright pigment dispersion is prepared by mixing 1 part by weight of a bright pigment, 4 parts by weight of ion-exchanged water, and 0.01 part by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R). The glitter pigment dispersion is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more, and then the volume average particle size is measured using Coulter Multisizer II type (manufactured by Coulter).

The glitter pigment used in the present embodiment is preferably a surface-treated pigment, more preferably a glitter pigment having a coating layer, silica, alumina coated on the surface of the glitter pigment. And a first coating layer containing at least one metal oxide selected from the group consisting of titania and a second coating layer containing a resin covering the surface of the first coating layer. More preferably it is.
The surface treatment method of the glitter pigment is not particularly limited, and a known surface treatment method may be used, but a method of forming the first and second coating layers by a method described later is preferable.

The first coating layer includes at least one metal oxide selected from the group consisting of silica, alumina, and titania, and these may be used alone or in combination of two or more. It may be used.
Among these, silica is preferable because it is excellent in chemical resistance when producing toner particles and can coat the pigment surface in a more uniform state.
The first coating layer may be formed only from the above metal oxide, but may contain impurities contained in the production.

In the glitter pigment, the element ratio (molar ratio) Mb / Ma between the metal Ma in the glitter pigment and the metal Mb in the first coating layer is preferably 0.08 or more and 0.20 or less. When the element ratio Mb / Ma is 0.20 or less, the light reflectance by the first coating layer is not lowered, and an image having excellent glitter can be formed. In addition, when the element ratio Mb / Ma is 0.08 or more, the coating on the surface of the glitter pigment becomes uniform, so that the transferability under high temperature and high humidity is improved.
The amount of element when obtaining the element ratio Mb / Ma is measured using a fluorescent X-ray analyzer (XRF).
Specifically, using a pressure molding machine, a disk having a diameter of 5 cm was produced by applying a compression pressure of 10 tons to 5 g of toner particles, and this was used as a measurement sample. Using this with an X-ray fluorescence analyzer (XRF-1500) manufactured by Shimadzu Corporation, the measurement conditions were a tube voltage of 40 KV, a tube current of 90 mA, and a measurement time of 30 minutes. The amount of metal elements in the layer can be measured.

As a method for coating the surface with a metal oxide, for example, a method of forming a coating layer of a metal oxide on the surface of the glitter pigment by a sol-gel method, a metal hydroxide is deposited on the surface of the glitter pigment, and crystallized at a low temperature. And a method of forming a metal oxide coating layer.
In the present embodiment, an organometallic compound is added so that the element ratio Mb / Ma is in the range of 0.08 to 0.20, and a hydrolysis catalyst is added to the dispersion containing the glitter pigment. By adjusting the pH of the dispersion liquid, it is preferable to deposit on the surface of the glitter pigment.

The coating amount of the first coating layer is preferably 10% by mass or more and 40% by mass or less, and more preferably 20% by mass or more and 30% by mass or less with respect to the mass of the glitter pigment.
The coating amount of the first coating layer is measured by a calibration curve obtained by measuring a mixture of an aluminum pigment and silica particles in advance with a fluorescent X-ray analyzer (XRF).

The glitter pigment preferably has the first coating layer and the second coating layer.
The second coating layer is preferably a resin coating layer.
As the resin used here, a known resin is used as a binder resin for toner particles, as will be described later, such as an acrylic resin or a polyester resin.
Among these, an acrylic resin is preferable because the pigment surface can be uniformly coated.
Further, from the viewpoint of excellent chemical resistance when producing toner particles and impact resistance, the second coating layer is preferably a layer made of a crosslinked resin.
The second coating layer may be formed only from the above resin, but may contain impurities and the like that are included during manufacturing.

The coating amount of the second coating layer is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, and more preferably 15% by mass with respect to the mass of the glitter pigment. % To 20% by mass is more preferable. When the coating amount of the second coating layer is 5% by mass or more, the coating property of the coating pigment by the binder resin is maintained, and a decrease in transferability under high temperature and high humidity is suppressed. In addition, since the coating amount of the second coating layer is 20% by mass or less, the regular reflectance is prevented from being lowered by the resin constituting the second coating layer, and an image excellent in glitter is obtained. It is formed.
Further, the coating amount of the second coating layer is a decrease in mass when the temperature is increased from 30 ° C. to 600 ° C. at a temperature increase rate of 30 ° C./min in a nitrogen stream using a calorimeter measuring device (TGA). Measured by rate.

When measuring the coating amount of the second coating layer of the coating pigment in the toner particles, the components such as the binder resin (and the release agent and other components) are dissolved and burned from the toner particles. After removing by such a method, the above method may be applied.
Further, since the release resin and other components are mixed in the binder resin in the toner particles, it is possible to distinguish the mixed region from the second coating layer in the coating pigment by using the second resin layer. You may measure the coating amount of a coating layer.

The following method is mentioned as an example of the formation method of a 2nd coating layer.
That is, the coated pigment on which the first coating layer is formed is solid-liquid separated, washed as necessary, dispersed in a solvent, a polymerizable monomer and a polymerization initiator are added with stirring, and heat treatment is performed. The resin is deposited on the surface of the glitter pigment. In this way, the second coating layer is formed.

  In the toner according to the exemplary embodiment, the content of the glitter pigment is preferably 1 to 70 parts by weight and more preferably 5 to 50 parts by weight with respect to 100 parts by weight of the toner.

Further, the toner base particles containing the glitter pigment are also referred to as glitter toner mother particles, and the toner containing the glitter toner mother particles is also referred to as glitter toner.
“Brightness” indicates that the image formed with the toner has a brightness such as a metallic luster when visually recognized. Quantitatively describing “metallic luster”, when a solid image is formed with glittering toner, the light receiving angle measured when incident light with an incident angle of −45 ° is irradiated to the image with a goniophotometer. The ratio (A / B) of the reflectance A at + 30 ° and the reflectance B at a light receiving angle of −30 ° is 2 or more and 100 or less. The ratio (A / B) is preferably 20 or more and 90 or less, and particularly preferably 40 or more and 80 or less. Within the above range, metallic luster can be observed with a wide viewing angle, and color images can be prevented from being dull. The ratio (A / B) is measured with a goniophotometer for a solid image with an applied toner amount of 4.5 g / m ² . Detailed conditions are described in paragraphs 0025 and 0026 of JP 2012-32765 A.

  The glittering toner will be described with reference to FIG. The glitter toner base particle 1 contains a binder resin 2 and glitter pigment particles 4. The glittering toner mother particles have a round round overall shape that may have irregularities on the surface, and the cross section of the particles parallel to the minor axis b includes the cross section of the flaky glitter pigment particles 4. It is.

-Array of glitter pigment particles in glitter toner base particles-
When observing a cross section in the thickness direction of the glitter toner base particles, the glitter pigment in which the angle between the major axis direction of the glitter toner particles and the major axis direction of the glitter pigment particles is in the range of −30 ° to + 30 °. It is preferable to contain bright toner mother particles whose number of particles is 60% or more with respect to the number of all bright pigment particles observed in the cross section.
According to a conventional method for observing the cross section of the toner, after embedding the glittering toner base particles in an epoxy resin, a cutting sample is prepared, and the cross section of the toner is observed with a transmission electron microscope (TEM). The number of pigment particles having the above specific arrangement is counted using image analysis software, and the ratio is calculated. The details are as follows.

-Angle between major axis direction of toner cross section and major axis direction of pigment particles-
When the cross section in the thickness direction of the toner is observed, the number of pigment particles in which the angle between the major axis direction of the toner and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is observed. It is preferable that it is 60% or more of the total pigment particles. Furthermore, the number is more preferably 70% or more and 95% or less, 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, LEICA ultramicrotome (manufactured by Hitachi High-Technologies Corporation)), and the observation sample is prepared. Make it. The cross section of the toner particles is observed with a transmission electron microscope (TEM) at a magnification of about 5,000 times. For the 1,000 toners observed, the number of pigment particles in which the angle between the major axis direction of the toner cross section and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is calculated using image analysis software. And calculate the ratio.
The above method is the same as the method described in paragraphs 0053 and 0054 of JP2012-32765A.

  Of the glittering pigment particles contained in the glittering toner mother particles, when the above-mentioned angle is in the range of −30 ° to + 30 °, the pigment particles are such that the surface side having the maximum area is the surface to be transferred. It is thought that they line up to face the surface of When the colored image thus formed is irradiated with light, the ratio of the pigment particles that diffusely reflect the incident light is suppressed, so that it is estimated that the metallic luster can be observed with a wide viewing angle.

-Binder resin-
The toner base particles contained in the toner used in this embodiment preferably contain a binder resin.
Examples of the binder resin include styrenes (eg, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (eg, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid). n-butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (for example, acrylonitrile, Methacrylonitrile, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, etc.) Emissions, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
As the binder resin, for example, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, non-vinyl resin such as modified rosin, a mixture of these with the vinyl resin, or these Examples also include a graft polymer obtained by polymerizing a vinyl monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of the polyester resin include known polyester resins.
As a polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as a polyester resin, a commercial item may be used and what was synthesize | combined may be used.
Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (eg, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.) Alicyclic dicarboxylic acids (for example, cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (for example, having 1 or more carbon atoms) 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, having 1 to 5 carbon atoms) alkyl esters.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K-1987 “Method for Measuring Transition Temperature of Plastics”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the polyester resin is preferably from 5,000 to 1,000,000, and more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the polyester resin is preferably 2,000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is carried out with a THF solvent using GPC / HLC-8120GPC as a measuring device, using a column / TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation. The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

The polyester resin is obtained by a well-known manufacturing method. Specifically, for example, the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation.
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.
The content of the binder resin is, for example, preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, and more preferably 60% by weight to 85% by weight with respect to the entire toner particles. Further preferred.

-Manufacturing method of toner base particles-
The method for producing the toner base particles of the present embodiment is not particularly limited, but is preferably produced by a wet method such as an emulsion aggregation method or a dissolution suspension method from the viewpoint of preventing exposure of the glitter pigment to the toner surface. .
The toner base particles of this embodiment can be made, for example, as follows.
The resin fine particles dispersed in water, pigment particles, and additive particles are mixed, stirred while applying an appropriate temperature, and an arbitrary amount of an aggregating agent is added to aggregate each particle. After adjusting the temperature and stirring speed to grow to the target particle size, aggregation is stopped by adjusting the pH in the liquid. Next, the temperature is raised to an appropriate temperature, and the aggregate resin is fused to form particles.
At this time, stirring at the time of aggregation is fast, the temperature is raised, and resin fine particles are added about 30% of the total resin content in the vicinity of the target particle size. After the aggregation is stopped, the temperature is increased while further stirring is performed. The toner base particles are easily flattened by fusing the resin.
In addition, by using a bright pigment having a major axis / minor axis number average ratio (minor axis / major axis) of 0.1 to 0.7, the number average ratio (b / Toner mother particles having a) of 0.1 to 0.7 can be easily obtained.

-Toner production method-
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner base particles as necessary after manufacturing the toner base particles.

-External additive-
Silica particles and other external additives may be externally added to the electrostatic image developing toner used in the exemplary embodiment. As the silica particles, silica particles produced by a dry method or a wet method are not particularly limited and are used.
Other external additives can be used without particular limitation, and known inorganic particles and organic particles are used as toner external additives. For example, alumina, titania (titanium oxide, metatitanic acid, etc.), cerium oxide, Examples thereof include inorganic particles such as zirconia, calcium carbonate, magnesium carbonate, calcium phosphate, and carbon black, and resin particles such as acrylic resin, polyester resin, and silicone resin. Further, the other external additives may be those that have been subjected to the hydrophobic treatment described above.
The average primary particle diameter of the silica particles and other external additives is preferably 3 to 500 nm, more preferably 5 to 300 nm, and still more preferably 5 to 150 nm.

-Release agent-
The toner for developing an electrostatic charge image of this embodiment preferably contains a release agent as an optional component.
Specific examples of the release agent include, for example, ester wax, polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene, but polyglycerin wax, microcrystalline wax, paraffin wax, carnauba wax, sazol wax, and montanic acid ester. Wax, deacidified carnauba wax, palmitic acid, stearic acid, montanic acid, blandic acid, eleostearic acid, valinalic acid and other unsaturated fatty acids, stearyl alcohol, aralkyl alcohol, bephenyl alcohol, carnauvyl alcohol, ceryl alcohol , Saturated alcohols such as long chain alkyl alcohols having a long chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amides Fatty acid amides such as oleic acid amide and lauric acid amide; saturated fatty acid bisamides such as methylene bis stearic acid amide, ethylene bis capric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide, ethylene bis oleic acid amide, Unsaturated fatty acid amides such as hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, N′— Aromatic bisamides such as distearyl isophthalic acid amide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally called metal soap); aliphatic hydrocarbon wax and styrene Waxes grafted with vinyl monomers such as acrylic acid; Partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; Methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils, etc. Is mentioned.

The said mold release agent may be used individually by 1 type, or may use 2 or more types together.
The content of the release agent is preferably 1 to 20% by weight and more preferably 3 to 15% by weight with respect to 100% by weight of the binder resin. Within the above range, both good fixing and image quality characteristics can be achieved.

(Image forming method)
An image forming method using the electrostatic charge image developer of this embodiment will be described. The electrostatic charge image developer of this embodiment is used in an image forming method using a known electrophotographic system. Specifically, it is used in an image forming method having the following steps.
That is, a preferred image forming method includes a latent image forming step of forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner. A developing step for forming an image, a transfer step for transferring the toner image to the surface of the transfer target, and a fixing step for fixing the toner image transferred to the surface of the transfer target. The toner for developing an electrostatic charge image is used. Further, the transfer step may use an intermediate transfer member that mediates transfer of the toner image from the image holding member to the transfer target.
Further, it may further include a cleaning step for removing residual toner on the surface of the image carrier after the transfer.

Each of the steps is a general step per se, and is described in, for example, Japanese Patent Laid-Open Nos. 56-40868 and 49-91231. Note that the image forming method of the present embodiment can be carried out by using a known image forming apparatus such as a copying machine or a facsimile machine.
The electrostatic latent image forming step is a step of forming an electrostatic latent image on an image carrier (photoconductor).
The developing step is a step of developing the electrostatic latent image with a developer layer on a developer holding member to form a toner image. The developer layer is not particularly limited as long as it contains the toner contained in the electrostatic charge image developer of this embodiment.
The transfer step is a step of transferring the toner image onto a transfer target. Examples of the transfer medium in the transfer process include an intermediate transfer medium and a recording medium such as paper.
In the fixing step, for example, there is a method of forming a copy image by fixing the toner image transferred onto the transfer paper by a heating roller fixing device in which the temperature of the heating roller is set to a constant temperature.
The cleaning step is a step of removing the electrostatic charge image developer remaining on the image carrier.
As the transfer target, a recording medium such as an intermediate transfer member or paper can be used.
Examples of the recording medium include paper used for electrophotographic copying machines and printers, OHP sheets, etc., for example, coated paper whose surface is coated with resin, art paper for printing, and the like. Etc. can be used suitably.

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

(Image forming device)
The image forming apparatus of this embodiment is an image forming apparatus using the electrostatic charge image developer of this embodiment. The image forming apparatus of this embodiment will be described.
The image forming apparatus according to this embodiment includes an image carrier, a charging unit that charges the image carrier, and an exposure unit that exposes the charged image carrier to form an electrostatic latent image on the surface of the image carrier. Developing means for developing the electrostatic latent image with toner to form a toner image; transfer means for transferring the toner image from the image carrier to the surface of the transfer body; and transferring the toner image to the surface of the transfer body. And a fixing means for fixing the toner image, and the developer containing the toner is preferably the electrostatic charge image developer of this embodiment.
The image forming apparatus according to the present exemplary embodiment is not particularly limited as long as it includes at least the image holding member, the charging unit, the exposure unit, the developing unit, the transfer unit, and the fixing unit as described above. However, other cleaning means, static elimination means, and the like may be included as necessary.
In the transfer unit, the transfer may be performed twice or more using an intermediate transfer member. Examples of the transfer medium in the transfer unit include an intermediate transfer medium and a recording medium such as paper.

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

In this image forming apparatus, for example, the part including the developing unit may be a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. As the process cartridge, a developer holding body is used. The process cartridge of the present embodiment is preferably used that includes at least the electrostatic charge image developer of the present embodiment.
Hereinafter, although an example of the image forming apparatus of this embodiment is shown, it is not necessarily limited to this. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

FIG. 2 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus including a developing device to which the electrostatic charge image developer of the present embodiment is applied.
In FIG. 1, the image forming apparatus of the present embodiment has a photosensitive drum 20 as an image holding member that rotates in a predetermined direction, and the photosensitive drum 20 is charged around the photosensitive drum 20. A charging device 21, for example, an exposure device 22 as a latent image forming device for forming an electrostatic latent image Z on the photosensitive drum 20, and a visible image of the electrostatic latent image Z formed on the photosensitive drum 20. Developing device 30, transfer device 24 that transfers a toner image visualized on photosensitive drum 20 onto recording paper 28 that is a transfer target, and cleaning that cleans residual toner on photosensitive drum 20 The devices 25 are sequentially 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 is developed to face the photosensitive drum 20. A developing roll (developing electrode) 33 serving as a toner holding member facing the developing opening 32 and applying a predetermined developing bias to the developing roll 33. A developing electric field is formed in the developing region between the photosensitive drum 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 in a region sandwiched between the charge injection roll 34 and the developing roll 33, and the charge is injected while being rubbed.

Next, the operation of the image forming apparatus will be described.
When the image forming process is started, first, the surface of the photosensitive drum 20 is charged by the charging device 21, and the exposure device 22 writes the electrostatic latent image Z on the charged photosensitive drum 20, and the developing device 30 then The electrostatic latent image Z is visualized as a toner image. Thereafter, the toner image on the photoconductive drum 20 is conveyed to a transfer site, and the transfer device 24 electrostatically transfers the toner image on the photoconductive drum 20 to a recording paper 28 that is a transfer target. The residual toner on the photosensitive drum 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.

<Developer cartridge, process cartridge>
The developer cartridge of this embodiment is not particularly limited as long as it contains an electrostatic charge image developer including the electrostatic charge image developer of this embodiment. The developer cartridge is, for example, attached to and detached from an image forming apparatus including a developing unit, and contains the electrostatic charge image developer of the present embodiment as a developer to be supplied to the developing unit. .
The developer cartridge may be a cartridge that stores toner and a carrier, or may be a cartridge that stores toner alone and a cartridge that stores a carrier separately.
It is preferable that the process cartridge of the present embodiment is attached to and detached from the image forming apparatus.
In addition, the process cartridge according to the present embodiment may include other members such as a static elimination unit as necessary.
As the process cartridge, a known configuration may be adopted. For example, Japanese Patent Application Laid-Open No. 2008-209489 and Japanese Patent Application Laid-Open No. 2008-233736 are referred to.
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 used in the above-described embodiment is accommodated and a toner holder that holds and conveys the toner is provided.

A process cartridge 200 shown in FIG. 3 includes a charging roller 108, a developing device 111 containing the electrostatic charge image developer of the above-described embodiment, a photosensitive member cleaning device 113, and a photosensitive member 107 as an image holding member. The opening 118 and the opening 117 for static elimination exposure are combined and integrated using a mounting rail 116. The process cartridge 200 is detachably attached to an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components not shown, and the image forming apparatus together with the image forming apparatus main body. It constitutes.
In FIG. 3, reference numeral 300 represents a transfer target.

  The process cartridge 200 shown in FIG. 3 includes a charging roller 108, a developing device 111, a photosensitive member cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. You may combine selectively. In the process cartridge of this embodiment, in addition to the developing device 111, the photosensitive member 107, the charging roller 108, the photosensitive member cleaning device (cleaning means) 113, the opening 118 for exposure, and the opening for static elimination exposure. At least one selected from the group consisting of the unit 117.

  Hereinafter, although an example and a comparative example are given and this embodiment is described more concretely, this embodiment is not limited to the following examples. Unless otherwise specified, “part” and “%” are based on mass.

(Measuring method)
<Ferrite and carrier particle size>
The volume average particle diameters of the ferrite particles and carriers as core materials are values measured using a laser diffraction / scattering type particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER). For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size that becomes 50% cumulative is defined as the volume average particle size D50v.

<Toner particle size>
As a method for measuring the volume average particle diameter of the toner particles, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% by weight aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant, and this is added to the electrolytic solution. Added in 100-150 ml. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute. By using the Coulter Multisizer II type (manufactured by Beckman Coulter, Inc.), an aperture having an aperture diameter of 100 μm is used. The particle size distribution of particles having a diameter in the range of 2.0 to 60 μm is measured. The number of particles to be measured is 50,000.
For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size that becomes 50% cumulative is defined as the volume average particle size D50v.

<Surface irregularities of ferrite particles>
The measurement method of the surface roughness Ry (maximum height) and the surface roughness Sm (average interval of unevenness) uses an ultra-depth color 3D shape measurement microscope (VK-9500, manufactured by Keyence Corporation) for 50 carriers. The method was determined by observing the surface at a magnification of 3,000 times.
For the maximum height Ry, a roughness curve is obtained, and a reference length is extracted in the direction of the average line. The height Yp from the average line of this extracted portion to the highest peak and the depth Yv to the lowest valley bottom The maximum height Ry is obtained by calculating the sum (Yp + Yv). The reference length for determining the Ry value is 10 μm, and the cutoff value is 0.08 mm. Sm (average interval of unevenness) obtains a roughness curve, and obtains an average value of the interval between the peaks and valleys obtained from the intersection where the roughness curve intersects the average line. The reference length for determining Sm (average interval of irregularities) is 10 μm, and the cutoff value is 0.08 mm. The surface roughness was measured according to JIS B 0601 (1994 version).

(Production of glitter pigment particles)
<Pigment particle 1>
1,000 g of commercially available pearl pigment (trade name: MM-100R, manufactured by Nihon Koken Kogyo Co., Ltd.) is dispersed in 4,000 g of isopropyl alcohol, 2,000 g of 2 mm glass beads are added, and the rotation speed is 20 rpm for 60 minutes. And crushed by a ball mill. The obtained pulverized product was filtered through a 200 μm mesh to remove the glass beads, followed by filtration and drying, and the pulverized product was taken out.
After sieving with a 25 μm mesh, the classification point was set to 0.5 μm and 3.0 μm with EJ-15 manufactured by Nippon Steel Mining Co., Ltd., and the intermediate powder was collected. The air volume at this time was 10 m ³ / min. The treatment with EJ-15 was repeated until the number average ratio of the minor axis to the major axis became 0.5. Pigment particles 1 were obtained by the above operation.

[Formation of first coating layer]
154 parts (100 parts as aluminum content) of the pigment particles 1 were added to 500 parts of methanol and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 15 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Then, the slurry was filtered, and the resulting slurry containing the coated glitter pigment was dried at 110 ° C. for 3 hours to obtain pigment particles 1 coated with silica.

[Formation of second coating layer]
500 parts of mineral spirit was added to the pigment particles 1 coated with silica and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.5 parts acrylic acid, 9.8 parts epoxidized polybutadiene, 12.2 parts trimethylolpropane triacrylate, 4.4 parts divinylbenzene, and 1.8 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated glitter pigment was dried at 150 ° C. for 3 hours. Thus, the pigment particle 1 which has a 1st coating layer and a 2nd coating layer was obtained.
Hereinafter, the pigment particle 1 having the first coating layer and the second coating layer was used as the pigment particle 1.

<Pigment particle 2>
Commercially available aluminum pigments (CR9800RM, manufactured by Asahi Kasei Chemicals Corporation) were classified to obtain pigment particles 2 having a ratio of the minor axis to the major axis of 0.5.
After sieving with a 25 μm mesh, the classification point was set to 0.5 μm and 3.0 μm with EJ-15 manufactured by Nippon Steel Mining Co., Ltd., and the intermediate powder was collected. The air volume at this time was set to 12 m ³ / min. The treatment with EJ-15 was repeated until the number average ratio of the minor axis to the major axis was 0.5.
A pigment particle 2 having a first coating layer and a second coating layer was prepared and used as the pigment particle 2 in the same manner as the pigment particle 1 except that the pigment particle 1 was changed to the pigment particle 2.

<Pigment particle 3>
Pigment particles 3 having a minor axis / major axis number average ratio of 0.05 were obtained in the same manner as pigment particles 2 except that the classification point was 0.4 μm, 2.9 μm, and the air volume was 9.
A pigment particle 3 having a first coating layer and a second coating layer was prepared and used as the pigment particle 3 in the same manner as the pigment particle 1 except that the pigment particle 1 was changed to the pigment particle 3.

<Pigment particle 4>
Pigment particles 4 having a minor axis / major axis number average ratio of 1.0 were obtained in the same manner as pigment particle 2 except that the classification point was 0.6 μm, 3.2 μm, and the air volume was 15.
Except for changing the pigment particle 1 to the pigment particle 4, the pigment particle 4 having the first coating layer and the second coating layer was prepared and used as the pigment particle 4 in the same manner as the pigment particle 1.

<Pigment particle 5>
Pigment particles 5 having a minor axis / major axis number average ratio of 0.09 were obtained in the same manner as in the pigment particles 1 except that the classification point was 0.8 μm, 3.8 μm, and the air volume was 15.
A pigment particle 5 having a first coating layer and a second coating layer was prepared and used as the pigment particle 5 in the same manner as the pigment particle 1 except that the pigment particle 1 was changed to the pigment particle 5.

(Manufacture of toner)
<Toner 1>
[Pigment dispersion 1]
Pearl pigment: Pigment particles 1: 100 parts by weight Anionic surfactant: Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.): 1.5 parts by weight Ion exchange water: 900 parts by weight Dispersion was carried out for 5 minutes with Turrax and for 10 minutes with an ultrasonic bath to obtain a pigment dispersion 1 having a solid content of 10%.
Details of the pigment particles 1 and the pigment particles 2 to 5 are shown in Table 1.

[Releasing agent dispersion 1]
Paraffin wax: HNP-9 (Nippon Seiwa Co., Ltd.): 19 parts by weight Anionic surfactant: Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.): 1 part by weight Ion exchange water: 80 parts by weight Then, the mixture was heated to 90 ° C. and stirred for 30 minutes. Next, the molten liquid is circulated from the bottom of the container to the gorin homogenizer, and under a pressure condition of 5 MPa, a circulation operation corresponding to 3 passes is performed. Then, the pressure is increased to 35 MPa, and further a circulation operation corresponding to 3 passes is performed. It was. The emulsion thus prepared was cooled in the heat-resistant solution to 40 ° C. or lower to obtain a release agent dispersion 1. It was 240 nm when the volume average particle diameter was measured with a Horiba Seisakusho particle size measuring instrument LA-700.

[Resin dispersion 1]
-Oil layer-
Styrene (manufactured by Wako Pure Chemical Industries, Ltd.): 30 parts by weight n-butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.): 10 parts by weight β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.): 1 .3 parts by weight dodecanethiol (manufactured by Wako Pure Chemical Industries, Ltd.): 0.4 parts by weight-water layer 1-
Ion-exchanged water: 17 parts by weight anionic surfactant (Dowfax, manufactured by Dow Chemical Co.): 0.4 parts by weight-aqueous layer 2-
Ion-exchanged water: 40 parts by weight anionic surfactant (Dowfax, manufactured by Dow Chemical Co.): 0.05 parts by weight ammonium peroxodisulfate (manufactured by Wako Pure Chemical Industries, Ltd.): 0.4 parts by weight The above oil layer components And the components of the aqueous layer 1 were placed in a flask and mixed with stirring to obtain a monomer emulsified dispersion. The components of the aqueous layer 2 were put into a reaction vessel, the inside of the vessel was sufficiently replaced with nitrogen, and the reaction system was heated to 75 ° C. with an oil bath while stirring. The above monomer emulsified dispersion was gradually dropped into the reaction vessel over 3 hours to carry out emulsion polymerization. After completion of the dropping, the polymerization was further continued at 75 ° C, and the polymerization was terminated after 3 hours.
The obtained resin fine particles have a volume average particle diameter D50v of the resin fine particles measured by a laser diffraction particle size distribution measuring apparatus LA-700 (manufactured by Horiba Ltd.) of 250 nm, which is a differential scanning calorimeter (DSC-50). , Manufactured by Shimadzu Corporation), the glass transition point of the resin was measured at a temperature rising rate of 10 ° C./min, and it was 53 ° C., and a molecular weight measuring instrument (HLC-8020 manufactured by Tosoh Corp.) was used. Was 13,000 when the number average molecular weight (in terms of polystyrene) was measured using as a solvent. As a result, a resin dispersion 1 having a volume average particle size of 250 nm, a solid content of 42%, a glass transition point of 52 ° C., and a number average molecular weight Mn of 13,000 was obtained.

[Toner mother particle 1]
Resin dispersion 1: 200 parts by weight Pigment dispersion 1: 100 parts by weight Release agent dispersion 1: 40 parts by weight Polyaluminum chloride: 0.4 parts by weight After thoroughly mixing and dispersing using Lux, the flask was heated to 52 ° C. with stirring in an oil bath for heating. At this time, the rotation speed of stirring was 500 rpm. (Rotation number 1) After holding at 52 ° C. for 80 minutes, 60 parts by weight of the same resin fine particle dispersion as above was gradually added thereto.
Thereafter, the stirring was increased to 600 rpm (rotation speed 2), the pH in the system was adjusted to 8.0 using a sodium hydroxide aqueous solution having a concentration of 0.5 mol / L, the stainless steel flask was sealed, and the stirring shaft was adjusted. The seal was magnetically sealed and heated to 97 ° C. at 3 ° C./1 minute (temperature increase 1) while stirring was continued for 3 hours. After the completion of the reaction, the temperature lowering rate was cooled at 1 ° C./min, filtered and thoroughly washed with ion-exchanged water, and then solid-liquid separation was performed by Nutsche suction filtration. This was further redispersed with 3 L of ion-exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This washing operation was further repeated 5 times, and when the pH of the filtrate was 6.54 and the electric conductivity was 6.5 μS / cm, No. was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper. Next, vacuum drying was continued for 12 hours to obtain toner base particles 1.
The volume average particle diameter D50v of the toner mother particles 1 was measured with a Coulter counter and found to be 14 μm. The number average ratio (b / a) of the minor axis to the major axis was 0.4.

Further, the toner base particles 1 are composed of silica (SiO ₂ ) fine particles having a primary particle average particle diameter of 40 nm and surface-hydrophobized with hexamethyldisilazane (hereinafter sometimes abbreviated as “HMDS”), metatitanic acid, and the like. Add a metatitanic acid compound fine particle having an average primary particle diameter of 20 nm, which is a reaction product of isobutyltrimethoxysilane, so that the coverage of the surface of the toner particle is 40%, mix with a Henschel mixer, and add toner 1 Created.

<Toner 2>
Toner 2 was obtained in the same manner as toner 1 except that pigment particle 1 was changed to pigment particle 2.

<Toner 3>
Toner 3 was obtained in the same manner as toner 1 except that pigment particle 1 was changed to pigment particle 3.

<Toner 4>
Toner 4 was obtained in the same manner as toner 1 except that pigment particle 1 was changed to pigment particle 4.

<Toner 5>
Toner 5 was obtained in the same manner as toner 1 except that pigment particle 1 was changed to pigment particle 2, rotation speed 2 was changed to 500 rpm, and temperature increase 1 was changed to 0.5 ° C./min.

<Toner 6>
In the production of toner 1, toner 6 was obtained in the same manner as toner 1 except that pigment particle 1 was changed to pigment particle 4, rotation speed 2 was changed to 650 rpm, and temperature increase 1 was changed to 3.5 ° C./min. .

<Toner 7>
[Colorant dispersion 1]
Cyan pigment: Copper phthalocyanine B15: 3 (manufactured by Dainichi Seika Kogyo Co., Ltd.): 50 parts by weight Anionic surfactant: Neogen SC (Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts by weight Ion exchange water: 200 parts by weight The above was mixed, and dispersed for 5 minutes by an Ultra-Turrax made by IKA and further for 10 minutes by an ultrasonic bath to obtain a colorant dispersion 1 having a solid content of 21%.
[Toner mother particles 7]
Resin dispersion 1: 150 parts by weight Colorant dispersion: 30 parts by weight Release agent dispersion 1:40 parts by weight Polyaluminum chloride: 0.4 parts by weight Toner except that toner base particles 1 are changed to toner base particles 7 In the same manner as in Example 1, a toner 7 was obtained.

<Toner 8>
Except that the pigment particle 1 of the toner 1 is changed to the pigment particle 5, the rotational speed 2 is changed to 700 rpm, the temperature rise 1 is changed to 4 ° C./1 minute, the 97 ° C. is changed to 98 ° C., and the holding time is changed to 3.5 hours. In the same manner, Toner 8 was obtained.

  Table 2 shows the number average ratio (b / a) and volume average particle diameter (D50v) of major axis a and minor axis b in the cross section of the pigment particles and toner base particles used for each toner.

(Carrier production)
[Coating solution 1]
Cyclohexyl acrylate resin (weight average molecular weight 50,000): 36 parts by weight Carbon black VXC72 (Cabot): 4 parts by weight Toluene: 250 parts by weight Isopropyl alcohol: 50 parts by weight The above components and glass beads (particle size: 1 mm, same amount as toluene) ) Was introduced into a sand mill manufactured by Kansai Paint Co., Ltd. and stirred at a rotational speed of 1,200 rpm for 30 minutes to prepare a coating solution 1 having a solid content of 11%.

[Ferrite particles 1]
1,318 parts by weight of Fe ₂ O ₃ , 586 parts by weight of Mn (OH) ₂ and 96 parts by weight of MgOH were mixed, and 0.5% by weight of the total titanium oxide was further added and mixed. Temporary baking was performed at a temperature of 3 hours. Next, 6.6 parts by weight of polyvinyl alcohol was added to the calcined product, 0.2 parts by weight of polycarboxylic acid, water and zirconia beads having a media diameter of 1 mm were crushed and dispersed by a sand mill. This was performed until the wet dispersed particle size became 1.5 μm, and then granulated and dried with a spray dryer so that the dry particle size became 38 μm. Furthermore, firing was performed in an electric furnace at 1,450 ° C. for 4 hours in a mixed atmosphere of nitrogen and oxygen in a mixed atmosphere having an oxygen partial pressure of 2%. The obtained particles were subjected to a crushing step and a magnetic force sorting step, and then additionally heated at a temperature of 800 ° C. for 4 hours, followed by a classification step to obtain ferrite particles 1 having a volume average particle diameter (D50) of 35 μm. The ferrite particles 1 had a surface roughness Sm of 3.5 and a maximum height Ry of 0.4.

[Ferrite particles 2]
Ferrite particles 2 were obtained in the same manner as the ferrite particles 1 except that the firing temperature was changed to 1,500 ° C. and the additional heating temperature was changed to 900 ° C. The volume average particle diameter (D50) of the ferrite particles 2 was 35 μm, the surface roughness Sm was 2.5, and the maximum height Ry was 0.3.

[Ferrite particles 3]
Ferrite particles 3 were obtained in the same manner as the ferrite particles 1 except that titanium oxide was not added and the firing temperature was changed to 1,400 ° C. The volume average particle diameter (D50) of the ferrite particles 3 was 35 μm, the surface roughness Sm was 1.0, and the maximum height Ry was 0.3.

[Ferrite particles 4]
Except for the addition of titanium oxide, the preliminary firing temperature is 750 ° C., the wet dispersion diameter is 5 μm, the firing temperature is 1,400 ° C., and the oxygen partial pressure is 5%. Ferrite particles 4 were obtained. The volume average particle diameter (D50) of the ferrite particles 4 was 35 μm, the surface roughness Sm was 3.0, and the maximum height Ry was 0.3.

[Ferrite particles 5]
The same as the ferrite particles 1 except that the pre-baking temperature was 900 ° C., the wet dispersed particle size was 3 μm, the baking temperature was 1,500 ° C., the oxygen partial pressure was 1.8%, and the additional heating temperature was 1,000 ° C. Thus, ferrite particles 5 were obtained. The volume average particle diameter (D50) of the ferrite particles 5 was 35 μm, the surface roughness Sm was 2.8, and the maximum height Ry was 0.6.

  Fluidity (seconds / 50 g) of each ferrite particle, titanium oxide addition amount (% by weight), provisional firing temperature (° C.), presence / absence of wet dispersion, wet dispersion particle size (μm), firing temperature (° C.), oxygen content The pressure (%) and the additional heating temperature (° C.) are as shown in Table 3, respectively. In addition, the ferrite particle described as "-" in the column of the addition amount of a titanium oxide has shown that the addition of the titanium oxide was not performed.

<Carrier 1>
Place 2,000 g of ferrite particles 1 in a vacuum degassing type 5 L kneader, and further add 550 g of coating liquid 1, and while stirring, reduce the pressure to −200 mmHg at 60 ° C., mix for 15 minutes, and then heat up / depressurize 94 The coated particles were obtained by stirring and drying at 30 ° C./−720 mHg for 30 minutes. Next, sieving was performed with a 75 μm mesh sieving net to obtain Carrier 1.

<Carrier 2>
A carrier 2 was obtained in the same manner as the carrier 1 except that the ferrite particle 1 was changed to the ferrite particle 2.

<Carrier 3>
A carrier 3 was obtained in the same manner as the carrier 1 except that the ferrite particle 1 was changed to the ferrite particle 3.

<Carrier 4>
Carrier 4 was obtained in the same manner as carrier 1 except that the coating liquid was changed to 730 g.

<Carrier 5>
A carrier 5 was obtained in the same manner as the carrier 1 except that the coating liquid was changed to 230 g.

<Carrier 6>
The carrier 6 was obtained in the same manner as the carrier 1 except that the ferrite particle 1 was changed to the ferrite particle 4 and the amount of the coating liquid 1 was changed to 640 g.

<Carrier 7>
Carrier 7 was obtained in the same manner as carrier 1 except that ferrite particle 1 was changed to ferrite particle 5 and the amount of coating liquid 1 was changed to 640 g.

<Carrier 8>
A carrier 8 was obtained in the same manner as the carrier 1 except that the ferrite particle 1 was changed to the ferrite particle 4.

<Carrier 9>
The carrier 9 was obtained in the same manner as the carrier 1 except that the ferrite particle 1 was changed to the ferrite particle 5 and the amount of the coating liquid 1 was changed to 640 g.

  For each carrier, the ferrite particles used, the ratio of the coating resin in the total mass of the carrier (coating amount%), and the fluidity (second / 50 g) are as shown in Table 4, respectively.

(Manufacture of developer)
<Developer 1>
500 g of carrier 1 and 30 g of toner 1 were placed in a V blender and mixed for 20 minutes. The resulting mixture was designated as developer 1.

<Developers 2-18>
Developers 2 to 18 were obtained in the same manner as Developer 1 except that Carrier 1 and Toner 1 were changed to the carriers and toners shown in Table 5.

Developers 1 to 18 listed in Table 5 were respectively charged in DocuCentre Color 400 (DCC400, Fuji Xerox Co., Ltd.) modified so that Cyan can be printed and the potential around development can be fixed. It was left to stand in an environment of 85% RH for 1 day.
After continuous printing of 100 sheets of 20 cm square solid printing, the process speed was reduced to half, and 100 sheets were printed in the same manner. The printed surface of the last printed matter was observed and evaluated according to the following evaluation criteria.
Evaluation criteria (image unevenness judgment / visual inspection)
5: No image unevenness on the surface 4: Image unevenness when enlarged 5 times 3: Some image unevenness visually 2: Image unevenness is clearly visible 1: Clearly image unevenness

  T: toner, 1: glitter toner mother particles, 2: binder resin, 4: glitter pigment particles, 20: photoconductor (image carrier) drum, 21: charging device, 22: exposure device, 24: transfer device , 25: cleaning device, 28: recording paper, 30: developing device, 31: developing housing, 32: developing opening, 33: developing roll, 34: charge injection roll, 40: toner, 107: photoconductor (image carrier) ), 108: charging roller, 111: developing device (developing means), 112: transfer device, 113: photoconductor cleaning device (cleaning means), 115: fixing device (fixing means), 116: mounting rail, 117: static elimination exposure 118: Opening for exposure, 200: Process cartridge, 300: Recording paper (transfer object), a: Long diameter in cross section of toner, b: In cross section of toner Kicking minor, Z: an electrostatic latent image

Claims (8)

An electrostatic charge image developing toner containing toner base particles, and
Including carriers,
The number average ratio (b / a) of the major axis a to the minor axis b in the cross section of the toner base particles is 0.1 to 0.7,
An electrostatic charge image developer, wherein the carrier has a fluidity of 24 to 28 seconds / 50 g.   The electrostatic charge image developer according to claim 1, wherein the carrier contains ferrite particles, and the fluidity of the ferrite particles is 26 to 29 seconds / 50 g.   The electrostatic charge image developer according to claim 2, wherein the ferrite particles have a surface roughness Sm of 1 to 5 μm and a maximum height Ry of 0.2 to 0.7 μm.   The electrostatic image development according to claim 1, wherein the toner contains a bright pigment having a number average ratio (minor axis / major axis) of a major axis and a minor axis of 0.1 to 0.7. Agent.   A developer cartridge containing the electrostatic charge image developer according to claim 1.   5. A process cartridge comprising a developer holder that contains the electrostatic charge image developer according to claim 1 and that holds and conveys the electrostatic charge image developer. An image carrier,
Charging means for charging the image carrier;
Exposure means for exposing the charged image carrier to form an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image;
Transfer means for transferring the toner image from the image carrier to the surface of the transfer target;
Fixing means for fixing the toner image transferred to the surface of the transfer target,
The developer is the electrostatic charge image developer according to any one of claims 1 to 4.
Image forming apparatus. A latent image forming step of forming an electrostatic latent image on the surface of the image carrier;
A development step of developing the electrostatic latent image formed on the surface of the image carrier with a developer containing toner to form a toner image;
A transfer step of transferring the toner image onto the surface of the transfer target;
Fixing a toner image transferred to the surface of the transfer target,
The electrostatic charge image developer according to any one of claims 1 to 4 is used as the developer.
Image forming method.

Images