JP2015152654A - Magnetic carrier, two-component developer, supply developer, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic carrier configured to maintain charge relaxation performance, to prevent charge-up of the amount of charges on toner, thereby preventing a white spot satisfactorily, while improving image density stability.SOLUTION: A magnetic carrier includes a magnetic material dispersed resin carrier core having a magnetic material and binder resin at least, and a resin coating layer formed on a surface of the magnetic material dispersed resin carrier core. The magnetic carrier has a 50% particle diameter (D50) of 20-60 μm on a volume basis. When a mass percent ratio between a resin-derived element and a metal component-derived element (resin-derived element/metal component-derived element) in an area R1 and an area R2 shown in Fig.1 is JR1 and JR2, respectively, the magnetic carrier satisfies the following relation: (1) 0.20≤JR1≤0.40, and (2) 1.00≤(JR1/JR2)≤1.40.

Description

  The present invention relates to a magnetic carrier, a two-component developer, a replenishing developer, and an image forming method using the same used in an image forming method for developing an electrostatic image using electrophotography. Is.

  Conventionally, an electrophotographic image forming method forms an electrostatic latent image on an electrostatic latent image carrier using various means, and attaches toner to the electrostatic latent image to form an electrostatic latent image. A developing method is generally used. For this development, there are a wide variety of two-component development systems in which carrier particles called magnetic carriers are mixed with toner, triboelectrically charged, imparted with an appropriate amount of positive or negative charge to the toner, and developed as a driving force. It has been adopted.

  The two-component development method can give functions such as developer agitation, conveyance, and charging to the magnetic carrier, so the function sharing with the toner is clear, and therefore the developer performance controllability is good. There is.

  On the other hand, in recent years, due to technological advancement in the field of electrophotography, there has been an increasingly strict requirement not only to increase the speed and life of the apparatus, but also to increase the definition and stabilize the image quality. In order to meet such a demand, high performance of the magnetic carrier is required.

  One of them is a proposal of a magnetic carrier in which the specific gravity of the magnetic carrier is reduced to reduce stress on the toner (Patent Document 1). This magnetic carrier is called a magnetic material-dispersed resin carrier, and is a magnetic material-dispersed resin carrier obtained by directly polymerizing spherical magnetite and a binder resin (phenol). However, the carrier as described above has a low specific gravity and lowering the magnetic force, so that high image quality and high definition can be achieved and the stress on the toner is reduced, but the toner is compatible with low-temperature fixing, and the toner spent. As a result, the life of the developer may be shortened. In addition, since a large amount of resin is present in the vicinity of the surface of the carrier core, this leads to a decrease in charge relaxation properties of the carrier. As a result, the toner at the rear end of the halftone part is scraped off at the boundary between the halftone image part and the solid image part, resulting in white streaks, and there is a concern that an image defect in which the edge of the solid image part is emphasized (hereinafter, white spot) occurs. There is.

  On the other hand, in order to improve the toner spent and improve the image quality, there has been proposed a magnetic carrier with an uneven surface (Patent Documents 2, 3, and 4). These are obtained by providing irregularities on the surface of the magnetic carrier using two kinds of magnetic particles having different shapes and particle sizes. However, these magnetic carriers improve the image quality and improve the toner spent property. However, the toner charge amount may be charged up in the long-term durability, and the image density may be lowered.

JP 2000-199985 A JP 2011-13676 A JP 2012-123213 A JP 2012-198422 A

  An object of the present invention is to provide a magnetic carrier, a two-component developer, and a replenishment developer that solve the above problems.

  Another object of the present invention is to provide a high-load type copier that has excellent charge relaxation properties even when continuous printing is performed for a long time, suppresses charge-up of the toner charge amount, and stably obtains high-quality images. It is an object of the present invention to provide a magnetic carrier, a two-component developer and a replenishment developer that can be used.

  As a result of intensive studies, the present inventors have found that a magnetic carrier and a two-component developer that suppresses white spots and fluctuations in image density before and after durability by using a magnetic material-dispersed resin carrier as shown below. It was found that it can be obtained.

That is, the present invention is a magnetic carrier dispersed resin carrier core having at least a magnetic body and a binder resin, and a magnetic carrier having a resin coating layer on the surface of the magnetic body dispersed resin carrier core,
The magnetic carrier has a 50% particle size (D50) based on volume distribution of 20 μm or more and 60 μm or less,
When the mass% ratio (resin-derived element / metal component-derived element) between the resin-derived element and the metal component-derived element in the region R1 and the region R2 defined as follows is defined as follows, the magnetic carrier is expressed as follows: It is related with the magnetic carrier characterized by satisfy | filling this relationship.
(1) 0.20 ≦ JR1 ≦ 0.40
(2) 1.00 ≦ (JR1 / JR2) ≦ 1.40

Definition of region R1:
In the cross-sectional image of the magnetic carrier, two straight lines that are parallel to the maximum length of the line segment A and separated from the line segment A by 2.5 μm are B and C. Assuming a straight line D passing through the intersection of the line segment and the magnetic carrier surface and perpendicular to the line segment, parallel to the straight line D and 5.0 μm away from the magnetic carrier toward the central direction of the magnetic carrier. A region surrounded by the magnetic carrier surface line between the straight lines B and C and the straight lines B, C, and E.

Definition of region R2:
A region surrounded by straight lines B, C, F, and G, where F and G are two straight lines that are parallel to the straight lines D and E and separated from the midpoint of the line segment A by 2.5 μm.

  The present invention also provides a two-component developer containing a toner containing a binder resin, a colorant and a release agent, and a magnetic carrier, wherein the magnetic carrier is a magnetic carrier having the above-described configuration. The present invention relates to a two-component developer.

Further, according to the present invention, a replenishment developer is replenished to the developing device in accordance with a decrease in the toner concentration of the two-component developer in the developing device, and an electrostatic latent image formed on the surface of the electrostatic latent image carrier is obtained. A replenishment developer for use in a two-component development method in which development is performed using a two-component developer in a developing device and excess magnetic carrier is discharged from the developing device as needed. There,
The replenishment developer includes a replenishment magnetic carrier and a toner containing a binder resin, a colorant, and a release agent, and a toner amount with respect to 1 part by mass of the replenishment magnetic carrier is 2 parts by mass or more and 50 parts by mass. And
The replenishing magnetic carrier is a magnetic carrier having the above-described configuration.

The present invention also provides a charging step for charging the electrostatic latent image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the surface of the electrostatic latent image carrier, and the electrostatic latent image in the developing device. Development using a two-component developer to form a toner image, a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer member, and transferring the transferred toner image to a transfer material An image forming method having a fixing step of fixing to
The present invention relates to an image forming method using the two-component developer having the above-described configuration as the two-component developer.

Further, according to the present invention, as the toner concentration of the two-component developer in the developing device decreases, the replenishment developer is supplied to the developing device, and the excess magnetic carrier in the developing device is supplied as necessary. An image forming method for discharging from a developing device,
The replenishment developer contains a replenishment magnetic carrier and a toner containing a binder resin, a colorant, and a release agent, and a toner amount with respect to 1 part by mass of the replenishment magnetic carrier is 2 parts by mass or more and 50 parts by mass. And
The replenishing magnetic carrier is a magnetic carrier having the above-described configuration.

  By using the magnetic carrier of the present invention, it is possible to improve the charge relaxation property and suppress the charge-up of the toner charge amount, thereby improving white spots and suppressing fluctuations in image density before and after durability. .

It is explanatory drawing of area | region R1 and R2 which concern on the magnetic carrier of this invention. 1 is a schematic diagram of an image forming apparatus used in the present invention. 1 is a schematic diagram of an image forming apparatus used in the present invention. It is the schematic of the apparatus of the specific resistance of the magnetic carrier used by this invention.

The magnetic carrier of the present invention is a magnetic material-dispersed resin carrier core having at least a magnetic material and a binder resin, and a magnetic material-dispersed resin carrier having a resin coating layer on the surface of the magnetic material carrier core. The volume average particle size of the body-dispersed resin carrier is 20.0 to 60.0 μm, and the mass% ratio of the resin-derived element and the metal component-derived element in the regions R1 and R2 defined as follows (from the resin) When the element / element derived from the metal component is JR1 and JR2, the magnetic carrier satisfies the following relationship.
(1) 0.20 ≦ JR1 ≦ 0.40
(2) 1.00 ≦ (JR1 / JR2) ≦ 1.40

  Here, the definition of the regions R1 and R2 will be described with reference to FIG. In the cross-sectional image of the magnetic carrier, two straight lines that are parallel to the maximum length of the line segment A and separated from the line segment A by 2.5 μm are B and C. Assuming a straight line D passing through the intersection of the line segment and the magnetic carrier surface and perpendicular to the line segment, parallel to the straight line D and 5.0 μm away from the magnetic carrier toward the central direction of the magnetic carrier. A region surrounded by the magnetic carrier surface line between the straight lines B and C and the straight lines B, C, and E is R1. The definition of the region R2 is parallel to the straight lines D and E. When two straight lines separated from the midpoint of the line segment A by 2.5 μm are F and G, the straight lines B, C, F and G It is an area surrounded by.

  By using the above-mentioned magnetic carrier, it is excellent in charge relaxation properties, can suppress the charge-up of the toner charge amount, improves white spot resistance and image density stability, and suppresses carrier adhesion. The method for controlling JR1 and JR2 will be described in the magnetic carrier manufacturing method described later.

  If JR1 is less than 0.20, the resin in the vicinity of the carrier surface is a thin layer, the charge relaxation property becomes excessively large, and the roughness and carrier adhesion deteriorate. On the other hand, if it exceeds 0.40, the charge relaxation property is insufficient, and image density fluctuation due to white spots or charge-up occurs.

  When JR1 / JR2 is less than 1.00, the charge relaxation property becomes too large, and the roughness and carrier adhesion are deteriorated. On the other hand, if it exceeds 1.40, the charge relaxation property cannot be obtained, and image density fluctuation due to white spots or charge-up occurs.

  The 50% particle size (hereinafter referred to as D50) based on the volume distribution of the magnetic material-dispersed resin carrier of the present invention is preferably 20.0 μm or more and 60.0 μm or less. As a result, the frictional charge imparting property to the toner is improved, the roughness of the halftone portion is satisfied, fogging can be suppressed, and carrier adhesion can be prevented.

In the cross-sectional image of the magnetic carrier, the magnetic-dispersed resin carrier contains magnetic particles A and magnetic particles B, and the number average particle diameters (μm) of the magnetic particles A and B are rA and rB, respectively. When the ratio of the cross-sectional area of the magnetic particle A to the total magnetic particle cross-sectional area in the R1 region and the R2 region is AR1 and AR2, respectively, it is preferable that the following regulations are satisfied.
(1) 0.30 ≦ rA ≦ 3.00
(2) 0.05 ≦ rB ≦ 0.25
(3) 0.00 ≦ (AR2 / AR1) ≦ 0.50

  By using the above-mentioned magnetic material-dispersed resin carrier, it is possible to control the abundance of the resin in the vicinity of the surface of the magnetic carrier, and as a result, it is possible to control charge relaxation and suppress charge-up. Prevents adhesion deterioration and image density fluctuation. Further, since the magnetic particles A having a large number average particle diameter are present more in the surface layer, unevenness can be imparted to the surface layer, the toner spent property is improved, the decrease in charge imparting ability is reduced even in long-term use, and the fog is reduced. Deterioration can be suppressed.

  When rA is less than 0.30 μm, the amount of resin between the magnetic bodies in the vicinity of the surface of the magnetic carrier is increased, charging relaxation cannot be obtained, and image density fluctuations and carrier adhesion occur due to white spots and charge-up. Further, unevenness on the surface of the magnetic carrier is reduced, and the toner spent property is deteriorated. On the other hand, when it exceeds 3.00 μm, the magnetic particles become too bulky, the resin near the surface of the magnetic carrier is thinned, the charge relaxation property becomes too large, and there is a concern that the roughness is deteriorated. In addition, the surface state of the coating resin becomes non-uniform, the charge imparting ability varies, and fogging and density fluctuation may occur.

  When rB is less than 0.05 μm, there is a concern that the magnetic particles B aggregate, the magnetic content of the magnetic carrier particles varies, and the carrier adhesion deteriorates. On the other hand, when it exceeds 0.25 μm, the content of the magnetic substance in the magnetic carrier is lowered, and carrier adhesion may occur.

  When AR2 / AR1 exceeds 0.50, the presence ratio of the magnetic particles A in the vicinity of the surface of the magnetic carrier is small, the presence ratio of the resin is large, charging relaxation is not obtained, and image density due to white spots or charge-up is increased. There are concerns about fluctuations and carrier adhesion.

  The magnetic particles A and B contained in the magnetic material-dispersed resin carrier are 0.51 ≦ wA / when the mass ratio (mass%) of the magnetic particles A and B in the magnetic material is wA and wB, respectively. It is preferable that (wA + wB) ≦ 0.80. By being in the above-mentioned range, it becomes possible to control the presence ratio of the resin and the magnetic body in the vicinity and inside of the magnetic carrier surface, and as a result, white spots and charge-up can be suppressed. If it is less than 0.51, the resin existing in the vicinity of the surface of the magnetic carrier is increased, the charge relaxation property is lowered, and there is a concern that image density fluctuation or carrier adhesion occurs due to white spots or charge-up. On the other hand, if it exceeds 0.80, the proportion of the resin in the vicinity of the surface of the magnetic carrier becomes small, the charge relaxation property becomes too large, and there is a concern about the deterioration of roughness.

  Details of the present invention will be described below.

<Magnetic carrier core>
The magnetic carrier core used in the present invention may be manufactured by either a kneading and pulverizing method or a polymerization method as long as it is a magnetic material-dispersed resin carrier core in which a magnetic material is dispersed in a binder resin. Among these, in order to control the presence state of the magnetic substance A and the magnetic substance B, a magnetic carrier core produced by a polymerization method is preferable.

  Magnetic particles used in the present invention include magnetic inorganic compound particles and nonmagnetic inorganic compound particles. Magnetic inorganic compound particles include magnetite particle powder, maghemite particle powder, magnetic iron oxide having one or more of silicon oxide, silicon hydroxide, aluminum oxide or aluminum hydroxide. Various kinds of powder particles, such as powder particles of barium, strontium or magnetoplumbite type ferrite particles containing barium-strontium, spinel type ferrite particles containing one or more selected from manganese, nickel, zinc, lithium and magnesium Magnetic iron compound particle powder can be used. Among these, magnetic iron oxide particle powders such as magnetite particle powders can be preferably used. Nonmagnetic inorganic compound particle powder includes nonmagnetic iron oxide particle powder such as hematite particle powder, nonmagnetic hydrous ferric oxide particle powder such as goethite particle powder, titanium oxide particle powder, silica particle powder, talc particle powder, Alumina particle powder, barium sulfate particle powder, barium carbonate particle powder, cadmium yellow particle powder, calcium carbonate particle powder and zinc white particle powder can be used. Among these, nonmagnetic iron oxide particle powder can be preferably used.

As a manufacturing method of a magnetic body, it can manufacture with the conventionally well-known manufacturing method of a wet method and a dry method. Specifically, in the production method, an aqueous alkali hydroxide solution having a concentration of 2 mol / L or more and 5 mol / L or less and a concentration of 0.5 mol / L or more and 2.0 mol / L are contained in a reaction vessel substituted with nitrogen gas. The following iron sulfate aqueous solution and zinc sulfate aqueous solution were added so that the molar ratio of alkali hydroxide to iron sulfate (number of moles of alkali hydroxide / number of moles of iron sulfate) was 1.0 to 5.0. To make a mixed solution. Next, further alkali hydroxide is added so as to obtain a desired pH. While maintaining the mixed solution at a temperature of 70 ° C. or higher and 100 ° C. or lower and stirring the oxidizing gas (air) into the reaction vessel, the mixture is stirred and mixed for 7 hours or longer and 15 hours or shorter to generate magnetite. Furthermore, the mixed solution containing the produced magnetite is filtered, washed with water, dried and pulverized to obtain magnetite. The reaction slurry viscosity can be controlled by the concentration of the aqueous iron sulfate solution added to the mixed solution, and the particle size distribution of the produced magnetite is adjusted. Further, the iron sulfate aqueous solution may contain a divalent metal ion such as Zn ²⁺ , Mn ²⁺ , Ni ²⁺ , Cr ²⁺ or Cu ²⁺ . Examples of the divalent metal ion source include sulfates, chlorides and nitrates thereof. Further, SiO ₂ may be contained as required, and silicate is used as a raw material.

  The shape and particle size distribution of the magnetic material can be controlled by stirring speed, reaction temperature, reaction field pH, reaction time, and addition of silicate. In order to obtain a spherical magnetic material, the pH is preferably 8 or less. On the other hand, in order to obtain an octahedral or amorphous magnetic material, the pH is preferably 10 or more.

  In the present invention, the shape of the magnetic particles to be used is not particularly limited, but the magnetic particles A that are largely present on the surface of the magnetic carrier are magnetic particles composed of a particle group (indefinite shape) having no specific shape. The body particles are desirable. Since the magnetic particles A have this shape, the toner spent resistance can be further improved.

  The magnetic carrier of the present invention may contain a dielectric material. By containing a dielectric substance, developability is improved and a stable image can be provided over a long period of time. Examples of the dielectric material include titanium oxide, titanate, and zirconate. Specific examples include barium titanate, strontium titanate, potassium titanate, magnesium titanate, lead titanate, titanium dioxide, barium zirconate, calcium zirconate, lead zirconate and the like.

  Examples of the binder resin used in the present invention include resins such as vinyl resins, polyester resins, epoxy resins, phenol resins, urea resins, polyurethane resins, polyimide resins, cellulose resins, silicone resins, acrylic resins, and polyether resins. . Resin may be 1 type, or 2 or more types of mixed resin may be sufficient as it. In particular, a phenol resin is preferable in terms of increasing the strength of the carrier core so as to retain a relatively large magnetic material. In order to increase the magnetic force of the carrier core and to control the specific resistance, the amount of the magnetic material is increased. Specifically, in the case of magnetite particles, it is preferably added at 80 mass% or more and 90 mass% or less with respect to the carrier core.

  An aqueous monomer, phenol and aldehyde are subjected to an addition polymerization reaction in an aqueous medium under a basic catalyst, and cured as a phenol resole resin. At this time, the magnetic material is put in an aqueous medium, the monomer and the magnetic material are uniformly slurried, and the core is formed by taking in the magnetic material when the reaction proceeds and the resin is cured. The presence state of the magnetic substance can be controlled by utilizing the affinity between the aqueous medium and the surface property of the magnetic substance.

  In order to control the presence of the magnetic bodies A and B, it is important that the surface of the magnetic body particles be oleophilic in advance when the carrier core is manufactured. The oleophilic treatment can be carried out by a method of treating with a coupling agent such as a silane coupling agent or a titanate coupling agent or by dispersing a magnetic substance in an aqueous solvent containing a surfactant. In that case, the magnetic body A can be preferentially present on the surface of the carrier core by changing the processing amount and processing type of the magnetic body A and the magnetic body B. Specifically, it is preferable to treat the hydrophilic substance with the magnetic substance A or reduce the lipophilic treatment amount of the magnetic substance A over the magnetic substance B.

<Resin coating layer>
The resin of the coating resin composition used for the coating layer is not particularly limited, but a vinyl resin that is a copolymer of a vinyl monomer having a cyclic hydrocarbon group in the molecular structure and another vinyl monomer is preferable. . By covering the vinyl resin, it is possible to suppress a decrease in charge amount in a high temperature and high humidity environment.

  Specific examples of the cyclic hydrocarbon group include cyclic hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, and cyclononyl group. A cyclodecyl group, an adamantyl group, an isobornyl group, a norbornyl group, an isobornyl group, and the like. Of these, a cyclohexyl group, a cyclopentyl group, and an adamantyl group are preferable, and a cyclohexyl group is particularly preferable from the viewpoint of structural stability, high adhesion to the core, and expression of releasability.

  Moreover, in order to adjust a glass transition temperature (Tg), you may contain another monomer as a structural component of vinyl-type resin.

  As another monomer used as a constituent component of the vinyl resin, a known monomer is used, and examples thereof include the following. Examples include styrene, ethylene, propylene, butylene, butadiene, vinyl chloride, vinylidene chloride, vinyl acetate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, vinyl methyl ether, vinyl ethyl ether, and vinyl methyl ketone.

  Furthermore, the vinyl resin used for the coating layer is preferably a graft polymer because a uniform coating layer is formed.

  In order to obtain a graft polymer, there are a method of graft polymerization after forming a backbone, and a method of copolymerization using a macromonomer as a monomer. This is preferable because it can be controlled in advance. The number average molecular weight of the graft portion is preferably 2000 or more and 10,000 or less, and more preferably 4000 or more and 6000 or less for improving adhesion.

  Although it does not specifically limit as a macromonomer used, Since a methyl methacrylate macromonomer raises the charge amount under high temperature and high humidity, it is preferable.

  The amount used when polymerizing the macromonomer is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, based on 100 parts by weight of the (co) polymer of the vinyl resin backbone.

  Further, the coating resin composition may be used by containing conductive particles or charge controllable particles or materials. Examples of the conductive particles include carbon black, magnetite, graphite, zinc oxide, and tin oxide. In order to adjust the resistance of the magnetic carrier, the addition amount of the conductive particles and materials is preferably 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the coating resin.

  Particles and materials having charge controllability include organometallic complex particles, organometallic salt particles, chelate compound particles, monoazo metal complex particles, acetylacetone metal complex particles, hydroxycarboxylic acid metal complex particles, and polycarboxylic acid. Acid metal complex particles, polyol metal complex particles, polymethyl methacrylate resin particles, polystyrene resin particles, melamine resin particles, phenol resin particles, nylon resin particles, silica particles, titanium oxide particles, alumina Examples include particles. The addition amount of particles and materials having charge controllability is preferably 0.5 parts by mass or more and 50.0 parts by mass or less with respect to 100 parts by mass of the coating resin in order to adjust the triboelectric charge amount.

  The coating resin composition is preferably 0.1 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the carrier core, from the viewpoints of coating film stability and charge imparting stability of the coating layer. More preferably, they are 1.0 mass part or more and 3.0 mass parts or less.

  A method for coating the coating resin composition is not particularly limited, and examples thereof include a coating method such as a dipping method, a kneader method, a spray method, a brush coating method, a dry method, and a fluidized bed. Among these, a dipping method, a kneader method, or a dry method that does not completely cover the corners of the magnetic material having the apex is preferable.

<Magnetic carrier>
The magnetic carrier of the present invention has a specific resistance at an electric field strength of 2000 V / cm of 1.0 × 10 ⁷ Ω · cm or more and 1.0 × 10 ¹⁵ Ω · cm or less in the specific resistance measurement described later. It is preferable from the viewpoint of compatibility between omission and halftone developability.

Magnetic properties of the magnetic carrier, the intensity of magnetization in 79.6 kA / m (1000 Oe) is preferably at most 50 Am ² / kg or more 70 Am ² / kg. More preferably, it is 55 Am ² / kg or more and 65 Am ² / kg or less.

<Toner>
Next, a preferable toner configuration for achieving the object in the present invention will be described in detail below.

  Examples of the binder resin used in the present invention include vinyl resins, polyester resins, and epoxy resins. Of these, vinyl resins and polyester resins are more preferable in terms of chargeability and fixability. In particular, when a polyester resin is used, the effect of introducing this apparatus is great.

  In the present invention, vinyl monomer monopolymer or copolymer, polyester, polyurethane, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic Petroleum resin or the like can be mixed with the above-described binder resin as necessary.

  When two or more kinds of resins are mixed and used as a binder resin, it is preferable that those having different molecular weights are mixed in an appropriate ratio as a more preferable form.

  The glass transition temperature of the binder resin is preferably 45 to 80 ° C., more preferably 55 to 70 ° C., the number average molecular weight (Mn) is 2,500 to 50,000, and the weight average molecular weight (Mw) is 10,000. It is preferable to be 1,000,000.

  As the binder resin, the following polyester resins are also preferable.

  In the polyester resin, 45 to 55 mol% of all components is an alcohol component, and 55 to 45 mol% is an acid component.

  The acid value of the polyester resin is preferably 90 mgKOH / g or less, more preferably 50 mgKOH / g or less, and the OH value is preferably 50 mgKOH / g or less, more preferably 30 mgKOH / g or less. This is because as the number of terminal groups of the molecular chain increases, the dependency of the toner on the environment increases in the environment.

  The glass transition temperature of the polyester resin is preferably 50 to 75 ° C, more preferably 55 to 65 ° C. The number average molecular weight (Mn) is preferably 1,500 to 50,000, more preferably 2,000 to 20,000. The weight average molecular weight (Mw) is preferably 6,000 to 100,000, more preferably 10,000 to 90,000.

  When the toner of the present invention is used as a magnetic toner, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, maghemite and ferrite, and iron oxides including other metal oxides; Fe, Co, Ni, etc. Metals or alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V , And mixtures thereof.

Specifically, examples of magnetic materials include triiron tetroxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), iron oxide zinc (ZnFe ₂ O ₄ ), and iron yttrium oxide (Y ₃ Fe). ₅ O ₁₂ ), iron cadmium oxide (CdFe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), copper iron oxide (CuFe ₂ O ₄ ), lead iron oxide (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), iron neodymium oxide (NdFe ₂ O ₃ ), iron barium oxide (BaFe ₁₂ O ₁₉ ), iron magnesium oxide (MgFe ₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ), iron lanthanum oxide (LaFeO ₃ ), iron powder (Fe), cobalt powder (Co), nickel powder (Ni) and the like.

  These may be used in an amount of 20 to 150 parts by mass, preferably 50 to 130 parts by mass, and more preferably 60 to 120 parts by mass with respect to 100 parts by mass of the binder resin.

  The following are mentioned as a nonmagnetic coloring agent used by this invention.

  Examples of the black colorant include carbon black; those adjusted to black using a yellow colorant, a magenta colorant, and a cyan colorant.

  Examples of the color pigment for magenta toner include the following. Examples include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48: 2, 48: 3, 48: 4, 49, 50, 51, 52, 53, 54, 55, 57: 1, 58, 60, 63, 64, 68, 81: 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, 269; I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35 are mentioned.

  The colorant may be used alone as a pigment, but it is preferable from the viewpoint of the image quality of a full-color image to improve the sharpness by using a dye and a pigment together.

  Examples of the magenta toner dye include the following. C. I solvent red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, 121, C.I. I. Disper thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, C.I. I. Oil-soluble dyes such as Disper Violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, C.I. I. Basic dyes such as basic violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28.

  Examples of the color pigment for cyan toner include the following. C. I. Pigment Blue 1, 2, 3, 7, 15: 2, 15: 3, 15: 4, 16, 17, 60, 62, 66; I. Bat Blue 6, C.I. I. Acid Blue 45, a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyls are substituted on the phthalocyanine skeleton.

  Examples of the color pigment for yellow include the following. Condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal compounds, methine compounds, allylamide compounds. Specifically, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 180, 181, 185, 191; I. Bat yellow 1, 3, and 20 are mentioned. In addition, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6 and Solvent Yellow 162 can also be used.

  The amount of the colorant used is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and most preferably 3 to 15 parts by mass with respect to 100 parts by mass of the binder resin. is there.

  Further, in the toner, it is preferable to use a toner obtained by mixing a colorant with a binder resin in advance to form a master batch. Then, the colorant can be favorably dispersed in the toner by melt-kneading the colorant master batch and other raw materials (binder resin, wax, etc.).

  In the toner of the present invention, a charge control agent can be used as necessary in order to further stabilize the chargeability. The charge control agent is preferably used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the binder resin. When the amount is less than 0.5 parts by mass, sufficient charging characteristics may not be obtained, which is not preferable. When the amount exceeds 10 parts by mass, compatibility with other materials is deteriorated or charging is performed under low humidity. It may be excessive, which is not preferable.

  Examples of the charge control agent include the following.

  As a negative charge control agent for controlling the toner to be negative charge, for example, an organometallic complex or a chelate compound is effective. Examples include monoazo metal complexes, aromatic hydroxycarboxylic acid metal complexes, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono and polycarboxylic acids and metal salts thereof, anhydrides or esters thereof, or phenol derivatives of bisphenol.

  Examples of the positive charge control agent for controlling the toner to be positively charged include modified products such as nigrosine and fatty acid metal salts, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and the like. As onium salts such as quaternary ammonium salts and their analogs such as phosphonium salts and their chelating pigments, triphenylmethane dyes and their lake pigments (as rake agents are phosphotungstic acid, phosphomolybdic acid, phosphotungsten) Molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound, etc.), diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide and dibutyltin as metal salts of higher fatty acids , Dioctyl tin borate include diorgano tin borate such as dicyclohexyl tin borate.

  In the present invention, if necessary, one or more release agents may be contained in the toner particles. Examples of the release agent include the following.

  Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax can be preferably used. In addition, oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes mainly composed of fatty acid esters such as carnauba wax, sazol wax, and montanic ester wax; and Examples include those obtained by partially or fully deoxidizing fatty acid esters such as deoxidized carnauba wax.

  The amount of the release agent is 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.

  The melting point of the releasing agent defined by the maximum endothermic peak temperature at the time of temperature rise measured by a differential scanning calorimeter (DSC) is preferably 65 to 130 ° C. More preferably, it is 80 to 125 ° C. If the melting point is less than 65 ° C., the viscosity of the toner decreases and toner adhesion to the photoreceptor is likely to occur. If the melting point exceeds 130 ° C., the low-temperature fixability may deteriorate, which is not preferable. .

  In the toner of the present invention, a fine powder that can be increased by adding the toner particles externally before and after the addition may be used as a fluidity improver. For example, fluorine resin powders such as vinylidene fluoride fine powder and polytetrafluoroethylene fine powder; wet production silica, fine powder silica such as dry production silica, fine powder titanium oxide, fine powder alumina, etc., silane coupling agent, titanium It is particularly preferable that the surface treatment is performed with a coupling agent and silicone oil, and the surface is hydrophobized, and the surface is hydrophobized as measured by a methanol titration test so as to show a value in the range of 30 to 80.

  The inorganic fine particles in the present invention are used in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, based on 100 parts by weight of the toner.

  When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio at that time is 2% by mass to 15% by mass, preferably 4% by mass as the toner concentration in the developer. When the content is from 13% to 13% by mass, good results are usually obtained. If the toner concentration is less than 2% by mass, the image density tends to decrease, and if it exceeds 15% by mass, fogging or in-machine scattering tends to occur.

  Further, in the replenishment developer for replenishing the developing device in accordance with the decrease in the toner concentration of the two-component developer in the developing device, the toner amount is 2 parts by mass or more and 50 masses per 1 part by mass of the magnetic carrier for replenishment. Or less.

  Next, an image forming apparatus provided with a developing device using the magnetic carrier, the two-component developer and the replenishing developer of the present invention will be described by way of example. The developing device used in the developing method of the present invention is described below. It is not limited to.

<Image forming method>
In FIG. 2, the electrostatic latent image carrier 1 rotates in the direction of the arrow in the figure. The electrostatic latent image carrier 1 is charged by a charger 2 that is a charging unit, and the surface of the charged electrostatic latent image carrier 1 is exposed by an exposure unit 3 that is an electrostatic latent image forming unit. Form an image. The developing device 4 has a developing container 5 for storing a two-component developer, the developer carrying member 6 is disposed in a rotatable state, and a magnetic field generating means is provided inside the developer carrying member 6 to provide a magnet. 7 is included. At least one of the magnets 7 is installed so as to face the latent image carrier. The two-component developer is held on the developer carrier 6 by the magnetic field of the magnet 7, the amount of the two-component developer is regulated by the regulating member 8, and the developer component is opposed to the electrostatic latent image carrier 1. Be transported. In the developing unit, a magnetic brush is formed by a magnetic field generated by the magnet 7. Thereafter, the electrostatic latent image is visualized as a toner image by applying a developing bias in which an alternating electric field is superimposed on a DC electric field. The toner image formed on the electrostatic latent image carrier 1 is electrostatically transferred to a recording medium (transfer material) 12 by a transfer charger 11. Here, as shown in FIG. 3, the image may be temporarily transferred from the electrostatic latent image carrier 1 to the intermediate transfer member 9 and then electrostatically transferred to the recording medium 12. Thereafter, the recording medium 12 is conveyed to a fixing device 13 where the toner is fixed on the recording medium 12 by being heated and pressurized. Thereafter, the recording medium 12 is discharged out of the apparatus as an output image. Incidentally, the toner remaining on the electrostatic latent image carrier 1 after the transfer process is removed by the cleaner 15. Thereafter, the electrostatic latent image carrier 1 cleaned by the cleaner 15 is electrically initialized by the light irradiation from the pre-exposure 16, and the image forming operation is repeated.

  FIG. 3 shows an example of a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus.

  The arrows indicating the arrangement and rotation direction of image forming units such as K, Y, C, and M in the figure are not limited to these. Incidentally, K means black, Y means yellow, C means cyan, and M means magenta. In FIG. 3, the electrostatic latent image carriers 1K, 1Y, 1C, 1M rotate in the direction of the arrow in the figure. Each electrostatic latent image carrier is charged by charging units 2K, 2Y, 2C, and 2M that are charging means, and an exposure unit 3K that is an electrostatic latent image forming unit is provided on the surface of each charged electrostatic latent image carrier. Exposure is performed with 3Y, 3C, and 3M to form an electrostatic latent image. Thereafter, the electrostatic latent image can be converted into a toner image by the two-component developer carried on the developer carrying members 6K, 6Y, 6C, and 6M provided in the developing devices 4K, 4Y, 4C, and 4M as developing means. Visualized. Further, the image is transferred to the intermediate transfer body 9 by the intermediate transfer chargers 10K, 10Y, 10C, and 10M which are transfer means. Further, the image is transferred to a recording medium 12 by a transfer charger 11 serving as a transfer unit, and the recording medium 12 is heated and pressure-fixed by a fixing unit 13 serving as a fixing unit and output as an image. Then, the intermediate transfer body cleaner 14 which is a cleaning member for the intermediate transfer body 9 collects transfer residual toner and the like. In the developing method of the present invention, specifically, an AC voltage is applied to the developer carrying member to form an alternating electric field in the developing region, and the developing is performed while the magnetic brush is in contact with the photosensitive member. It is preferable. The distance between the developer carrying member (developing sleeve) 6 and the photosensitive drum (distance between S and D) is preferably not less than 100 μm and not more than 1000 μm in terms of preventing carrier adhesion and improving dot reproducibility. If it is smaller than 100 μm, the supply of the developer tends to be insufficient, and the image density is lowered. If it exceeds 1000 μm, the magnetic lines of force from the magnetic pole S1 spread and the density of the magnetic brush is lowered, so that the dot reproducibility is inferior, or the force that restrains the magnetic coat carrier is weakened, and the carrier adheres easily.

  The voltage (Vpp) between peaks of the alternating electric field is 300 V or more and 3000 V or less, preferably 500 V or more and 1800 V or less. The frequency is 500 Hz to 10000 Hz, preferably 1000 to 7000 Hz, and can be appropriately selected depending on the process. In this case, the waveform of the AC bias for forming the alternating electric field includes a triangular wave, a rectangular wave, a sine wave, or a waveform with a changed duty ratio. In order to cope with the change in the formation speed of the toner image sometimes, it is preferable to perform development by applying a developing bias voltage (intermittent alternating voltage) having a discontinuous AC bias voltage to the developer carrier. . When the applied voltage is lower than 300 V, it is difficult to obtain a sufficient image density, and the fog toner in the non-image portion may not be recovered well. If the voltage exceeds 3000 V, the latent image may be disturbed via the magnetic brush, leading to a reduction in image quality.

  By using a two-component developer with well-charged toner, the anti-fogging voltage (Vback) can be lowered and the primary charge of the photoreceptor can be lowered, thus extending the life of the photoreceptor. it can. Vback is 200 V or less, more preferably 150 V or less, although it depends on the development system. The contrast potential is preferably 100 V or more and 400 V or less so that a sufficient image density is obtained.

  Further, when the frequency is lower than 500 Hz, although related to the process speed, the structure of the electrostatic latent image bearing photoconductor may be the same as that of a photoconductor used in an image forming apparatus. For example, a photoreceptor having a structure in which a conductive layer, an undercoat layer, a charge generation layer, a charge transport layer, and a charge injection layer as necessary are provided on a conductive substrate such as aluminum or SUS in order.

  The conductive layer, undercoat layer, charge generation layer, and charge transport layer may be those usually used for a photoreceptor. For example, a charge injection layer or a protective layer may be used as the outermost surface layer of the photoreceptor.

  The measurement of various physical properties according to the present invention will be described below.

<Method for Measuring Volume Average Particle Size (D50) of Magnetic Carrier>
The particle size distribution was measured with a laser diffraction / scattering particle size distribution measuring apparatus “Microtrack MT3300EX” (manufactured by Nikkiso Co., Ltd.).

The volume average particle size (D50) of the magnetic carrier was measured by mounting a sample feeder “One Shot Dry Sample Conditioner Turbotrac” (manufactured by Nikkiso Co., Ltd.) for dry measurement. As the supply conditions of Turbotrac, a dust collector was used as a vacuum source, the air volume was about 33 l / sec, and the pressure was about 17 kPa. Control is automatically performed on software. For the particle size, a 50% particle size (D50), which is a cumulative value of volume average, is obtained. Control and analysis are performed using attached software (version 10.3.3-202D). The measurement conditions are as follows.
SetZero time: 10 seconds Measurement time: 10 seconds Number of measurements: 1 time Particle refractive index: 1.81%
Particle shape: Non-spherical measurement upper limit: 1408 μm
Measurement lower limit: 0.243 μm
Measurement environment: 23 ° C., 50% RH

<Measurement method of number average particle diameter of magnetic material>
The particle size distribution of the magnetic material is measured before the magnetic carrier core is manufactured. When measuring from a magnetic carrier, the coating resin composition is removed from the magnetic carrier using chloroform, the carrier core is placed on an alumina boat, baked in a muffle furnace at 600 ° C. for 1 hour, and the particles ground in an agate mortar are measured. .

The magnetic material is observed under the following conditions using a scanning electron microscope (SEM) and S-4800 (manufactured by Hitachi High-Technologies Corporation).
SignalName = SE (U, LA80)
AcceleratingVoltage = 2000Volt
EmissionCurrent = 11000nA
Working distance = 8000um
LensMode = High
CondenSer1 = 5000
ScanSpeed = Capture_Slow (20)
Magnification = 30000 (used for measurement)
DataSize = 1280 × 960
ColorMode = Grayscale
SpecimenBias = 0V

  In addition to the above-described conditions, the reflected electron image is captured by adjusting the brightness to contrast = 5 and brightness = −5 on the control software of the scanning electron microscope S-4800, and turning off the magnetic body observation mode. A grayscale image with 256 gradations is obtained.

  Subsequently, the obtained image is enlarged and printed on A3 paper, and the horizontal ferret diameter is measured. The scale on the photograph is converted into the actual length, and (0.016 μm-0.023 μm), (0.023 μm-0.033 μm), (0.033 μm-0.047 μm), (0.047 μm-0. 066 μm), (0.066 μm-0.094 μm), (0.094 μm-0.133 μm), (0.133 μm-0.187 μm), (0.187 μm-0.265 μm), (0.265 μm-0. 375 μm), (0.375 μm-0.530 μm), (0.530 μm-0.750 μm), (0.750 μm-1.060 μm), (1.060 μm-1.499 μm), (1.499 μm-2. 121 μm), (2.121 μm−2.999 μm), and (2.999 μm−4.241 μm) are assigned to 16 columns, and the particle size distribution is calculated. As the number average particle diameter, an arithmetic average particle diameter is used.

  Specifically, when calculating the number average particle diameter, all the particles are classified into the above columns, and the intermediate value (representative particle diameter) of each column is multiplied by the relative particle amount (difference%) to obtain the total relative particle amount. Divide by (100%).

First, the particle size range to be measured (maximum particle size: x ₁ , minimum particle size: x _{n + 1} ) is divided into n, and each particle size section is divided into [x _j , x _{j + 1} ] (j = 1). , 2,..., N). The division in this case is an equal division on a logarithmic scale. Moreover, the representative particle diameter in each particle diameter area based on a logarithmic scale is represented by the following formula.

Further, r _j (j = 1, 2,..., N) is set as the relative particle amount (% difference) corresponding to the particle diameter interval [x _j , x _{j + 1} ], and the total of all the intervals is 100%. Then, the average value μ on the logarithmic scale can be calculated by the following formula.

Since μ is a numerical value on a logarithmic scale and does not have a unit as a particle diameter, 10 ^μ, that is, a power of 10 ^μ is calculated in order to return to the unit of the particle diameter. This 10 ^μ is ^defined as the number average particle diameter.

<Measurement of resistivity of magnetic carrier>
The specific resistance of the magnetic carrier is measured using a measuring apparatus schematically shown in FIG. The magnetic carrier measures the specific resistance at an electric field strength of 2000 (V / cm).

The resistance measurement cell A has a cylindrical container (made of ATFE resin) 17, a lower electrode (made of stainless steel) 18, a support base (made of PTFE resin) 19, and an upper electrode (made of stainless steel) having a cross-sectional area of 2.4 cm ^2. 20 is composed. The cylindrical container 17 is placed on the support pedestal 19, the sample (magnetic carrier or carrier core) 21 is filled to a thickness of about 1 mm, the upper electrode 20 is placed on the filled sample 5, and the thickness of the sample is increased. taking measurement. As shown in FIG. 4 (a), the gap when there is no sample is d1, and as shown in FIG. 4 (b), the gap when the sample is filled so that the thickness is about 1 mm is d2. The thickness d of the sample is calculated by the following formula.
d = d2-d1 (mm)

  At this time, the mass of the sample is appropriately changed so that the thickness d of the sample is 0.95 mm or more and 1.04 mm or less.

  The specific resistance of the sample can be determined by applying a DC voltage between the electrodes and measuring the current flowing at that time. For the measurement, an electrometer 22 (Kesley 6517A, manufactured by Kesley) and a processing computer 23 are used for control.

  A control system and control software (LabVEIW National Instruments) manufactured by National Instruments were used as a control processing computer.

As measurement conditions, a measured value d is inputted so that the contact area S of the sample and the electrode is S = 2.4 cm ² and the thickness of the sample is 0.95 mm or more and 1.04 mm or less. The load of the upper electrode is 270 g and 1000 V.
Specific resistance (Ω · cm) = (applied voltage (V) / measured current (A)) × S (cm ² ) / d (cm)
Electric field strength (V / cm) = applied voltage (V) / (cm)

  The specific resistance at the electric field strength of the magnetic carrier reads the specific resistance at the electric field strength on the graph from the graph.

<Measurement method of magnetic carrier magnetization intensity>
The strength of magnetization of the magnetic carrier can be obtained by a vibrating magnetic field measuring device (Vibrating sample magnetometer) or a direct current magnetization characteristic recording device (BH tracer). In the present invention, the measurement is performed by the following procedure using an oscillating magnetic field type magnetic property measuring apparatus BHV-30 (manufactured by Riken Electronics Co., Ltd.).

A cylindrical plastic container filled with a magnetic carrier sufficiently densely is used as a sample, and the magnetization moment in an external magnetic field of 79.6 kA / m (1000 Oe) is measured. In the measurement, the hysteresis loop is measured so that the maximum external magnetic field on the plus side (+79.6 kA / m) is applied and then the maximum negative external magnetic field (−79.6 kA / m) is applied. The average of the absolute values of the positive and negative maximum values at that time is defined as the maximum magnetization moment (emu). In addition, the actual mass of the magnetic carrier filled in the container is measured. The magnetization intensity (Am ² / kg) of the magnetic carrier is obtained by dividing the maximum magnetization moment by the mass (g).

<Calculation method of mass ratio of resin-derived element and metal component-derived element in cross section of magnetic carrier>
1. Cutting out a cross section A focused ion beam processing observation apparatus (FIB) and FB-2100 (manufactured by Hitachi High-Technologies Corporation) were used for cross-section processing of the magnetic carrier. A sample was prepared by applying a carbon paste on an FIB sample stage (metal mesh), fixing a small amount of magnetic carrier on each of the FIB sample stands so as to exist independently, and depositing platinum as a conductive film. The sample was set in an FIB apparatus, and rough processing (beam current: 39 nA) was performed using an acceleration voltage of 40 kV and a Ga ion source, followed by finishing (beam current: 7 nA), and the carrier cross section as a sample was cut out.

  The cross section of the magnetic carrier selected as the measurement sample is D50 × 0.9 ≦ H ≦ D50 ×, where H is the length of the line segment A that is the maximum length of the magnetic carrier shown in FIG. A magnetic carrier of 1.1 was targeted, and a cross-sectional sample in this range was used.

2. Analysis of magnetic component and resin component of magnetic carrier Using scanning electron microscope (manufactured by Hitachi, Ltd., S4700), the elements of the magnetic carrier cross-sectional sample magnetic component and resin component attached to the scanning electron microscope Analysis was performed using an analysis means (energy dispersive X-ray analyzer, manufactured by EDAX).

  The observation magnification was set to 10,000 times or more, and an area composed of only the metal component was observed at an acceleration voltage of 20 kV and an acquisition time of 100 sec to identify elements in the metal component. For example, in the case of magnetite, the element was iron because of iron oxide. The elements in the case of magnetite to which a metal component that is not a magnetic component is added, such as titanium, are iron and titanium.

  Since oxygen is contained in both the metal component and the resin component, and it is difficult to specify the content ratio, it was excluded from the resin component. Further, when hydrogen is present, the energy dispersive X-ray analyzer used in the present invention cannot identify hydrogen, so hydrogen is also excluded from the resin component. Therefore, in a phenolic or acrylic resin composed of carbon, hydrogen, and oxygen, carbon is used as an element serving as a resin component. In the silicone resin, carbon and silicon are used as the elements to be the resin component.

3. Measurement of cross section resin abundance Using a scanning electron microscope, the magnetic carrier cross section was magnified 2000 times and observed. In the obtained cross-sectional image, two straight lines that are parallel to the maximum length of the line segment A and separated from the line segment A by 2.5 μm are defined as B and C. Assuming a straight line D passing through the intersection of the line segment and the magnetic carrier surface and perpendicular to the line segment, parallel to the straight line D and 5.0 μm away from the magnetic carrier toward the central direction of the magnetic carrier. A region surrounded by the magnetic carrier surface line between the straight lines B and C and the straight lines B, C, and E was defined as R1. Further, when two straight lines that are parallel to the straight lines D and E and separated by 2.5 μm from the midpoint of the line segment A are F and G, they are surrounded by straight lines B, C, F, and G. The region was R2.

  The element mass ratio (mass%) was measured for each of the R1 and R2 regions using an elemental analysis means at an acceleration voltage of 20 kV and an uptake time of 100 sec.

  For example, in the case of a magnetic carrier composed of magnetite as the magnetic material, phenolic resin as the binder resin, and acrylic resin as the coating resin, the element derived from the metal component (ie, magnetite) is iron, and the resin component The derived element is carbon. At this time, the mass ratio (mass%) of carbon and iron elements in the R1 region is JR1 (resin-derived element / metal component-derived element), and the mass ratio (mass%) of carbon and iron elements in the R2 region is JR2 ( Resin-derived element / metal component-derived element).

  In the present invention, the above measurement was performed with 100 particles of the magnetic carrier, and the average value of 80 particles obtained by cutting the upper and lower 10 points of the obtained value was taken as the values of JR1 and JR2 of the magnetic carrier.

<Calculation method of area ratio of magnetic particles A in R1 and R2 regions of magnetic carrier cross section>
The area ratio (hereinafter referred to as AR1 and AR2) of the magnetic particles A in the R1 and R2 regions of the magnetic carrier cross section is the magnetic used in the calculation method of the mass ratio of the resin-derived element and the metal component-derived element in the magnetic carrier cross section. Calculated with a carrier cross-section sample. In the obtained cross-sectional image, two straight lines that are parallel to the maximum length of the line segment A and separated from the line segment A by 2.5 μm are defined as B and C. Assuming a straight line D passing through the intersection of the line segment and the magnetic carrier surface and perpendicular to the line segment, parallel to the straight line D and 5.0 μm away from the magnetic carrier toward the central direction of the magnetic carrier. A region surrounded by the magnetic carrier surface line between the straight lines B and C and the straight lines B, C, and E was defined as R1. Further, when two straight lines that are parallel to the straight lines D and E and separated by 2.5 μm from the midpoint of the line segment A are F and G, they are surrounded by straight lines B, C, F, and G. The region was R2.

  In scanning electron microscope observation, the amount of reflected electrons emitted depends on the atomic number of the substance constituting the sample, so that a composition image of the magnetic carrier cross section can be obtained. In cross-sectional observation of a magnetic carrier, for example, a heavy element region derived from a magnetite component is bright (high brightness and white), and a light element region derived from a resin component and voids is dark (low brightness). Observe).

  Specifically, the acceleration voltage of the scanning electron microscope was set to 2.0 kV, and the cross section of the magnetic carrier was observed at 2000 times. Subsequently, a 5.0 μm square is drawn in the R1 and R2 regions from the scale in the image using PowerPoint (manufactured by Microsoft). An enlarged print is made on A3 paper, and the outline of the magnetic particles in the R1 and R2 regions is traced on the image using tracing paper or an OHP film. “Magnetic particles A” or “magnetic particles B” color-code each particle.

Next, the magnetic particle image on the tracing paper is captured by the camera. For the created image, the ratio of the area occupied by each particle in the R1 and R2 regions is calculated using image analysis software Image-ProPlus (ver. 5.1.1.32 manufactured by Media Cybernetics).
Area ratio of magnetic particles A (area%) = sum of areas of magnetic particles A / (sum of areas of magnetic particles A + sum of areas of magnetic particles B) × 100

  This operation was measured for 100 magnetic carrier particles, and the average value for 80 particles obtained by cutting the upper and lower 10 points of the obtained value was used as the AR1 and AR2 values of the magnetic carrier.

<Measuring method of weight average particle diameter (D4) and number average particle diameter (D1) of toner>
The weight average particle diameter (D4) and number average particle diameter (D1) of the toner are measured by a fine particle size distribution measuring apparatus “Coulter Counter Multisizer 3” (registered trademark, Beckman And a dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data were used. Measurement was performed with 25,000 effective measurement channels, and measurement data was analyzed and calculated.

  As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.

  Prior to measurement and analysis, the dedicated software was set as follows.

  In the “Standard Measurement Method (SOM) Change Screen” of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.

  In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated in a state where the phase is shifted by 180 degrees, and placed in a water tank of an ultrasonic dispersion device “Ultrasonic Dissipation System Tetora 150” (manufactured by Nikki Bios Co., Ltd.) having an electrical output of 120 W. Add a fixed amount of ion-exchanged water. About 2 ml of the aforementioned contamination N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) and the number average particle diameter (D1) are calculated. When the graph / volume% is set with the dedicated software, the “average diameter” on the analysis / volume statistics (arithmetic average) screen is the weight average particle size (D4), and the graph / number% is set with the dedicated software. The “average diameter” on the analysis / number statistic (arithmetic average) screen is the number average particle diameter (D1).

<Calculation method of fine powder amount>
The number-based fine powder amount (number%) in the toner is calculated as follows.

  For example, the number% of particles having a particle size of 4.0 μm or less in the toner is measured by the above-described Multisizer 3 and (1) graph / number% is set with dedicated software, and the measurement result chart is displayed in number%. To do. (2) Check “<” in the particle size setting portion on the format / particle size / particle size statistics screen, and enter “4” in the particle size input section below. Then, (3) when the analysis / count statistics (arithmetic mean) screen is displayed, the numerical value of the “<4 μm” display portion is the number% of particles of 4.0 μm or less in the toner.

<Calculation method of coarse powder amount>
The volume-based coarse powder amount (volume%) in the toner is calculated as follows.

  For example, the volume% of particles of 10.0 μm or more in the toner is measured by the above-mentioned Multisizer 3 and (1) graph / volume% is set with dedicated software and the measurement result chart is displayed as volume%. To do. (2) Check “>” in the particle size setting portion on the format / particle size / particle size statistics screen, and enter “10” in the particle size input section below. (3) When the analysis / volume statistics (arithmetic average) screen is displayed, the numerical value of the “> 10 μm” display portion is the volume% of particles of 10.0 μm or more in the toner.

  Hereinafter, the present invention will be specifically described with reference to production examples and examples, but this does not limit the present invention in any way.

<Preparation of magnetic particles A-1>
Fe ₂ O ₃ is mixed and pulverized in a wet ball mill for 10 hours. Add 1 part by weight of polyvinyl alcohol and granulate and dry with a spray dryer. Firing was performed at 900 ° C. for 10 hours in an electric furnace under an atmosphere of nitrogen with an oxygen concentration of 0.0 vol%.

  The obtained magnetic material is pulverized with a dry ball mill for 5 hours, classified with an air classifier (Elbow Jet Lab EJ-L3, manufactured by Nippon Steel Mining Co., Ltd.), and fine particles and coarse particles are classified and removed at the same time. -1 was obtained.

  The obtained magnetic particles A-1 and a silane coupling agent (3-glycidoxypropylmethyldimethoxysilane) (0.2 parts by mass with respect to 100 parts by mass of magnetite fine particles) were introduced into a container. . Then, the magnetic particles A-1 were subjected to surface treatment by high-speed mixing and stirring at 100 ° C. for 1 hour in the container.

<Preparation of magnetic particles B-1>
While supplying nitrogen gas at a rate of 18 L / min to a reaction vessel having a gas blowing tube, 26.7 L of ferrous sulfate aqueous solution containing 1.5 mol / L of Fe ²⁺ and 0.2 mol / L of Si ⁴⁺ are included. Sodium silicate No. 3 aqueous solution (1.0 L) was added to 3.4 mol / L sodium hydroxide aqueous solution (22.3 L), and the pH was raised to 6.8 and the temperature was raised to 90 ° C. Further, 1.2 L of 3.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH to 7.9, stirring was continued, the gas was changed to air, and aeration was performed at 100 L / min for 90 minutes. The pH was neutralized to pH 7 using dilute sulfuric acid, and the produced particles were washed with water, filtered, dried, and pulverized to obtain magnetic particles B-1.

  The obtained magnetic particles B-1 and a silane coupling agent (3-glycidoxypropylmethyldimethoxysilane) (1.4 parts by mass with respect to 100 parts by mass of magnetite fine particles) were introduced into a container. . And in this container, high-speed mixing stirring was carried out at 100 degreeC for 1 hour, and the magnetic body particle B-1 was surface-treated.

<Preparation of magnetic particles A-2 to 11, B-2 to 8>
Magnetic particles having a changed shape and particle size distribution of the magnetic particles are obtained by the reaction temperature of the magnetic particles B-1, the pH of the reaction field, the reaction time, and the addition of silicate. Except for changing to the conditions shown in Table 1, the surface treatment is performed in the same manner as the magnetic particles B-1.

<Surface treatment of dielectric particles>
A flask is charged with 1000 parts by mass of 1.0 μm TiO _2, and a silane coupling agent (3-glycidoxypropylmethyldimethoxysilane) (1.2 parts by mass with respect to 100 parts by mass of dielectric particles) is added. After stirring, the dielectric particles are surface-treated by high-speed mixing and stirring at about 100 ° C. for 1 hour.

<Preparation of magnetic carrier core>
・ Phenol 10.0 mass parts ・ Formaldehyde solution (formaldehyde 37 mass% aqueous solution) 15.0 mass parts ・ Surface-treated magnetic particles A-1 60.0 mass parts ・ Surface-treated magnetic particles B-1 30.0 Part by mass / surface-treated dielectric particles (TiO ₂ ) 10.0 parts by mass / 25% by mass Ammonia water 3.5 parts by mass / water 15.0 parts by mass The above materials were introduced into a reaction kettle to a temperature of 40 ° C. Mix well. Thereafter, the mixture is heated to 85 ° C. at an average heating rate of 1.5 ° C./min with stirring, maintained at a temperature of 85 ° C., and cured by polymerization for 3 hours. The peripheral speed of the stirring blade at this time is 1.96 m / sec.

  After the polymerization reaction, the mixture is cooled to a temperature of 30 ° C. and water is added. The precipitate obtained by removing the supernatant is washed with water and further air-dried. The obtained air-dried product was dried at a temperature of 60 ° C. under reduced pressure (5 hPa or less) to obtain a magnetic carrier core 1 in which magnetic particles were dispersed.

<Preparation of magnetic carrier cores 2 to 21>
Magnetic carrier cores 2 to 21 were manufactured in the combinations shown in Table 2 in the same manner as the magnetic carrier core 1 conditions.

<Preparation of magnetic carrier>
The magnetic carrier core 1 was put into a planetary motion type mixer (Nauta mixer VN type manufactured by Hosokawa Micron Corporation) maintained at a temperature of 60 ° C. under reduced pressure (1.5 kPa). With respect to 100 mass parts, it charged so that it might become 1.2 mass parts as solid content of a resin component. As a method of charging, a 1/3 amount of the resin solution was charged, and solvent removal and coating operation were performed for 20 minutes. Next, a 1/3 amount of the resin solution was added, and the solvent was removed and applied for 20 minutes. Further, a 1/3 amount of the resin solution was added, and the solvent was removed and applied for 20 minutes.

  Thereafter, the magnetic carrier coated with the coating resin composition is transferred to a mixer (drum mixer UD-AT type manufactured by Sugiyama Heavy Industries Co., Ltd.) having spiral blades in a rotatable mixing container. The mixture container was heat-treated at a temperature of 120 ° C. for 2 hours under a nitrogen atmosphere while stirring at 10 rotations per minute. The obtained magnetic carrier 1 was classified by a magnetic classifier after separating a low-magnetic force product by magnetic separation, passing through a sieve having an opening of 150 μm. A magnetic carrier 1 having a volume average particle diameter (D50) of 35.0 μm was obtained. Table 3 shows the physical properties of the magnetic carrier 1 obtained.

  The metal component-derived component is iron and titanium, and the resin-derived component is carbon.

<Preparation of magnetic carriers 2 to 21>
Similarly to the magnetic carrier 1, the magnetic carriers 2 to 21 were resin-coated using the resin solutions shown in Table 2.

  The conditions of the obtained magnetic carrier are shown in Table 2, and the physical properties are shown in Table 3.

  The element derived from the metal component of the magnetic carrier 2 and 4 to 21 is iron, and the element derived from the resin component is carbon. The element derived from the metal component of the magnetic carrier 3 is iron, and the elements derived from the resin component are silicone and carbon.

[Production Example of Toner 1]
-Binder resin (polyester resin) 100 parts by mass-C.I. I. Pigment Blue 15: 3 4.5 parts by mass, 1,4-di-t-butylsalicylic acid aluminum compound 0.5 part by mass, normal paraffin wax (melting point: 78 ° C.) 6 parts by mass (FM-75 type, manufactured by Nihon Coke Co., Ltd.) (The kneaded material temperature at the time of discharge was about 150 ° C.). The obtained kneaded product was cooled, coarsely crushed with a hammer mill, and then finely pulverized with a mechanical pulverizer (T-250: manufactured by Turbo Kogyo Co., Ltd.) at a Feed amount of 15 kg / hr. A particle having a weight average particle size of 5.5 μm, 55.6% by number of particles having a particle size of 4.0 μm or less, and 0.8% by volume of particles having a particle size of 10.0 μm or more is obtained. It was.

  The obtained particles were classified using a rotary classifier (TTSP100, manufactured by Hosokawa Micron Corporation) to cut fine powder and coarse powder. Cyan toner particles 1 having a weight average particle size of 6.4 μm, an abundance of particles having a particle size of 4.0 μm or less, 25.8% by number, and 2.5% by volume of particles having a particle size of 10.0 μm or more Got.

Further, the following materials were put into a Henschel mixer (FM-75 type, manufactured by Nippon Coke Co., Ltd.), the peripheral speed of the rotary blade was set to 35.0 (m / sec), and mixing was performed for 3 minutes. Cyan toner 1 was obtained by attaching silica and titanium oxide to the surfaces of the particles 2.
-Cyan toner particles 1 100 parts by mass-Silica 3.5 parts by mass (Silica fine particles prepared by the sol-gel method were surface-treated with 1.5% by mass of hexamethyldisilazane and then adjusted to a desired particle size distribution by classification) .)
・ 0.5 parts by mass of titanium oxide (surface-treated with an octylsilane compound of metatitanic acid having anatase crystallinity)

  Table 5 shows the formulation and physical property values of the obtained toner.

[Example 1]
9 parts by mass of toner 1 was added to 91 parts by mass of magnetic carrier 1, and shaken with a shaker (YS-8D type: manufactured by Yayoi Co., Ltd.) to prepare 300 g of a two-component developer. The amplitude condition of the shaker was 200 rpm for 2 minutes.

  On the other hand, 90 parts by mass of toner 1 was added to 10 parts by mass of magnetic carrier 1 and mixed for 5 minutes with a V-type mixer in an environment of normal temperature and normal humidity of 23 ° C./50% RH to obtain a replenishment developer. .

  The following evaluation was performed using the two-component developer and the replenishment developer.

  As an image forming apparatus, a Canon color copier imageRUNNER ADVANCE C9075 PRO remodeling machine was used.

  A two-component developer was placed in the developing unit, a replenishment developer container containing a replenishment developer was set, an image was formed, and various evaluations were performed before and after the durability test.

  As a durability test, an FFH output chart with an image ratio of 1% was used in a printing environment at a temperature of 23 ° C./humidity of 5 RH% (hereinafter “N / L”). In a printing environment of a temperature of 30 ° C./humidity of 80 RH% (hereinafter “H / H”), an FFH output chart with an image ratio of 40% was used. FFH is a value representing 256 gradations in hexadecimal, 00h is the first gradation (white background) of 256 gradations, and FFH is the 256th gradation (solid part) of 256 gradations. .

The number of image outputs was changed according to each evaluation item.
conditions:
Paper Laser beam printer paper CS-814 (81.4 g / m ² )
(Canon Marketing Japan Inc.)
Image formation speed A4 size, full color, modified to output at 80 (sheets / min)
It was.
Development conditions The development contrast can be adjusted to any value, and automatic correction by the copier itself is possible.
Modified to not work.
The voltage (Vpp) between the peaks of the alternating electric field has a frequency of 2.0 kHz and Vpp
Modified to change from 0.7kV to 1.8kV in increments of 0.1kV
It was.
Each color was modified to output a single color image.

  Each evaluation item is shown below.

(1) Image density fluctuation After performing durability initial and durable image output evaluation (2400 sheets) in an N / L environment (23 ° C., 5% RH), a solid image (FFH) was formed. Density measurement was performed with a densitometer X-Rite 404A (manufactured by X-Rite), and an average value of 6 points was taken as an image density. The difference in image density between the initial durability and the output of the durable image was judged according to the following criteria.
A: Difference in density is less than 0.05 (very good)
B: Difference in density is 0.05 or more and less than 0.10 (good)
C: Difference in density is 0.10 or more and less than 0.15 (somewhat good)
D: Concentration difference is 0.15 or more and less than 0.20 (acceptable level in the present invention)
E: Difference in density is 0.20 or more (impossible level in the present invention)

(2) White spot After performing durable image output evaluation (2400 sheets) in an NL environment (23 ° C., 5% RH), a halftone horizontal band (30H width 10 mm) and solid in the transfer paper conveyance direction A chart in which black horizontal bands (FFH width 10 mm) are alternately arranged is output. The image is read by a scanner and binarized. A luminance distribution (256 gradations) of a certain line in the conveyance direction of the binarized image was taken. Draw a tangent line to the brightness of the halftone at that time, and the brightness area (area: sum of brightness numbers) that deviates from the tangent at the rear end of the halftone part until it intersects with the solid part brightness. Based on the evaluation.
A: Less than 10 (very good)
B: 10 or more and less than 20 (good)
C: 20 or more and less than 30 (slightly good)
D: 30 or more and less than 40 (Acceptable level in the present invention)
E: 40 or more (impossible level in the present invention)

(3) Carrier adhesion after durability After durability image output evaluation (2400 sheets) was performed in an N / L environment (23 ° C., 5% RH), carrier adhesion was evaluated. A 00H image and an FFH image were output, the power was turned off in the middle of image output, and sampling was performed by attaching a transparent adhesive tape to the electrostatic latent image carrier before cleaning. Then, the number of magnetic carrier particles adhering to the electrostatic charge latent image carrier in 3 cm × 3 cm was counted, the number of adhering carrier particles per 1 cm ² was calculated, and evaluated according to the following criteria. The evaluation was performed with cyan single color.
A: 2 or less (very good)
B: 3 or more and 4 or less (good)
C: 5 or more and 7 or less (slightly good)
D: 8 or more and 10 or less (allowable level in the present invention)
E: 11 or more (impossible level in the present invention)

(4) Roughness of halftone image After initial and durability image output evaluation (100,000 sheets) in H / H environment, one halftone image (30H) was printed with A4. For the image, a digital microscope VHX-500 (lens wide range zoom lens VH-Z100, manufactured by Keyence Corporation) was used, and the area of 1000 dots was measured. The number average (S) of dot areas and the standard deviation (σ) of dot areas were calculated, and the dot reproducibility index was calculated by the following formula. Then, the roughness of the halftone image was evaluated by the dot reproducibility index (I).
Dot reproducibility index (I) = σ / S × 100

As an evaluation standard of the roughness, it was evaluated by the following standard for cyan single color.
A: I is less than 3.0 (very good)
B: I is 3.0 or more and less than 5.0 (good)
C: I is 5.0 or more and less than 7.0: (slightly good)
D: I is 7.0 or more and less than 9.0 (acceptable level in the present invention)
E: I is 9.0 or more (impossible level in the present invention)

(5) Fog After performing durable initial stage and durable image output evaluation (100,000 sheets) in a fogging H / H environment (30 ° C., 80% RH), an A4 full solid white image was output. For the fog, the whiteness of the white background was measured with a reflectometer (manufactured by Tokyo Denshoku), the fog density (%) was calculated from the difference in whiteness before and after the transfer, and evaluated according to the following criteria.
A: Less than 1.5% (very good)
B: 1.5% or more and less than 2.0% (good)
C: 2.0% or more and less than 2.5% (slightly good)
D: 2.5% or more and less than 3.0% (acceptable level in the present invention)
E: 3.0% or more (impossible level in the present invention)

(6) Comprehensive judgment The evaluation ranks in the evaluation items (1) to (5) are quantified (A = 10, B = 7, C = 5, D = 3, E = 0), and the total value is based on the following criteria. Judgment was made.
A: 47 or more and 50 or less: very good.
B: 35 or more and 46 or less: Good.
C: 25 or more and 34 or less: In the present invention, an acceptable level as a high-quality copying machine.
D: 15 or more and 24 or less: An image defect is anxious, but there is no problem in actual use.
E: 14 or less: Unacceptable level in the present invention.

  In Example 1, very good results were obtained in any evaluation. The evaluation results are shown in Table 6.

[Example 2]
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 2 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

In Example 2, since the dielectric particles were not contained in the magnetic carrier core, there was a slight difference in white spots compared to Example 1, but in any evaluation, very good results were obtained. there were. The evaluation results are shown in Table 6.
Magnetic particles A

Example 3
In the same manner as in Example 1, using the magnetic carrier 3, a two-component developer and a replenishment developer were prepared at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 3, the mass ratio of the magnetic particles A was high, and a slight variation occurred in the thickness of the coating resin layer. As a result, there was a slight difference in roughness, but the other results were generally good. The evaluation results are shown in Table 6.

Example 4
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 4 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 4, the mass ratio of the magnetic particles A was low, and the resin presence ratio in the vicinity of the surface of the magnetic carrier was high. As a result, there was a slight difference in white spots, but the other results were very good. The evaluation results are shown in Table 6.

Example 5
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 5 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 5, the mass ratio of the magnetic particles A is high, and the volume average particle size of the magnetic carrier is also large. Therefore, a slight variation in the thickness of the coating resin layer causes a decrease in charge imparting ability. As a result, although slight influence was recognized by roughness and fogging, the result was generally good. The evaluation results are shown in Table 6.

Example 6
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 6 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 6, the mass ratio of the magnetic particles A is low, the volume average particle diameter of the magnetic carrier is also small, and the resin existing ratio in the vicinity of the magnetic carrier surface is high. For this reason, the charge relaxation property is slightly affected, and there is a slight difference in white spots, but the results are generally good. The evaluation results are shown in Table 6.

Example 7
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 7 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 7, particles having a larger number average particle diameter are used for the magnetic particles B. As a result, the amount of the magnetic substance in the magnetic carrier became smaller and the magnetization became lower. For this reason, there was a slight influence on the carrier adhesion, but the other results were generally good. The evaluation results are shown in Table 6.

Example 8
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 8 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 8, particles having a smaller number average particle diameter are used for the magnetic particles B. When adjusting the magnetic carrier, the magnetic particles B partially aggregated, and as a result, the magnetization between the magnetic carriers slightly varied. For this reason, there was a slight influence on the carrier adhesion, but the other results were generally good. The evaluation results are shown in Table 6.

Example 9
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 9 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 9, larger particles having a larger number average particle diameter are used for the magnetic particles A, and the volume average particle diameter of the magnetic carrier is also larger. Therefore, a slight variation in the thickness of the coating resin layer caused a slight influence on the charge imparting ability, but the result was generally good. The evaluation results are shown in Table 6.

Example 10
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 10 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 10, since particles having a smaller number average particle diameter are used as the magnetic particles A, the resin existing ratio on the surface of the magnetic carrier is increased. As a result, the charge-up property and the charge relaxation property were affected, and a slight difference was observed in image density fluctuation before and after endurance, white spots and carrier adhesion, but the results were generally good. The evaluation results are shown in Table 6.

Example 11
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 11 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 11, since the number average particle diameter of the magnetic particles A is small, the magnetic particles B are large particles. As a result, the difference in the number average particle diameter of the magnetic particles A and B became smaller, and the resin existing ratio in the magnetic carrier and in the vicinity of the surface became closer. For this reason, the charge relaxation properties are affected, and there is a difference in white spots, but the results are generally good. The evaluation results are shown in Table 6.

Example 12
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 12 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 12, since particles having a small number average particle diameter were used for the magnetic particles B, aggregation of the magnetic particles B was observed when adjusting the magnetic carrier. As a result, the magnetization between the magnetic carriers varied and the carrier adhesion was affected, but the other results were generally good. The evaluation results are shown in Table 6.

Example 13
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 13 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 13, particles having a large number average particle diameter are used as the magnetic particles A, and the volume average particle diameter of the magnetic carrier is also large. For this reason, the resin abundance ratio in the vicinity of the magnetic carrier surface was lowered, the thickness of the coating resin layer was slightly varied, and the charge imparting ability was affected. As a result, there was a difference in roughness and fogging, but the other results were generally good. The evaluation results are shown in Table 6.

Example 14
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 14 in the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 14, particles having a small number average particle diameter of the magnetic particles A are used. As a result, the resin existing ratio on the surface of the magnetic carrier was increased. For this reason, the charge relaxation property was affected, and white spots were affected, but the level was not problematic in actual use. The evaluation results are shown in Table 6.

Example 15
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 15 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 15, the abundance ratio of the magnetic particles A at the center of the magnetic carrier was increased, and as a result, the resin abundance at the vicinity of the magnetic carrier surface was increased. Therefore, the charge-up property and the charge relaxation property are affected, and there are differences in the image density fluctuation before and after the endurance, white spots and carrier adhesion. The evaluation results are shown in Table 6.

Example 16
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 16 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 16, both the magnetic particles A and B use particles having a large number average particle diameter, and the volume average particle diameter of the magnetic carrier is also large. For this reason, the resin abundance ratio in the vicinity of the magnetic carrier surface was lowered, the thickness of the coating resin layer was slightly varied, and the charge imparting ability was affected. As a result, although there was a difference in all the evaluation items, it was a level with no problem in actual use. The evaluation results are shown in Table 6.

Example 17
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 17 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Example 17, both the magnetic particles A and B use particles having a small number average particle size. As a result, the resin presence rate in the vicinity of the magnetic carrier surface was increased. Therefore, the charge-up property and the charge relaxation property are affected, and there are differences in the image density fluctuation before and after the endurance, white spots and carrier adhesion. The evaluation results are shown in Table 6.

[Comparative Example 1]
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 18 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Comparative Example 1, a magnetic carrier having a small number average particle diameter of the magnetic particles A, a large number average particle diameter of the magnetic particles B, and a low mass ratio of the magnetic particles A was used. As a result, the resin existing ratio in the vicinity of the surface of the magnetic carrier becomes too high, which has a great influence on the charge relaxation property and the charge-up property. There was a tendency for image density fluctuation before and after endurance, white spots and carrier adhesion to deteriorate. The evaluation results are shown in Table 6.

[Comparative Example 2]
Similarly to Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 19 in the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Comparative Example 2, since the number average particle diameter of the magnetic particles A is too large, the resin existing ratio in the vicinity of the magnetic carrier surface is lowered, the thickness of the coating resin layer is greatly varied, and the charge imparting ability is lowered. It was seen. As a result, the image density fluctuation before and after the endurance, the roughness resistance and the fog were deteriorated. The evaluation results are shown in Table 6.

[Comparative Example 3]
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 20 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Comparative Example 3, since the volume average particle diameter of the magnetic carrier was too large, the charge imparting ability was low, and in particular, the fog and the anti-fogging resistance were deteriorated. The evaluation results are shown in Table 6.

[Comparative Example 4]
In the same manner as in Example 1, a two-component developer and a replenishment developer were prepared using the magnetic carrier 21 at the same ratio as in Example 1. Evaluation was performed in the same manner as in Example 1 except that the obtained developer was used.

  In Comparative Example 4, since the volume average particle diameter of the magnetic carrier was too small, the content of the magnetic substance in the magnetic carrier was reduced, the amount of magnetization was low, and the resin existing ratio in the vicinity of the magnetic carrier surface was high. As a result, there was a tendency for image density fluctuation and carrier adhesion due to charge-up to deteriorate. The evaluation results are shown in Table 6.

  1, 1K, 1Y, 1C, 1M: electrostatic latent image carrier, 2, 2K, 2Y, 2C, 2M: charger, 3, 3K, 3Y, 3C, 3M: exposure unit, 4, 4K, 4Y, 4C 4M: developing device, 5: developing container, 6, 6K, 6Y, 6C, 6M: developer carrier, 7: magnet, 8: regulating member, 9: intermediate transfer member, 10K, 10Y, 10C, 10M: intermediate Transfer charger, 11: Transfer charger, 12: Recording medium (transfer material), 13: Fixing device, 14: Intermediate transfer body cleaner, 15, 15K, 15Y, 15C, 15M: Cleaner, 16: Pre-exposure

Claims (7)

A magnetic material-dispersed resin carrier core having at least a magnetic material and a binder resin, and a magnetic carrier having a resin coating layer on the surface of the magnetic material-dispersed resin carrier core,
The magnetic carrier has a 50% particle size (D50) based on volume distribution of 20 μm or more and 60 μm or less,
When the mass% ratio (resin-derived element / metal component-derived element) between the resin-derived element and the metal component-derived element in the region R1 and the region R2 defined as follows is defined as follows, the magnetic carrier is expressed as follows: A magnetic material-dispersed resin carrier characterized by satisfying the relationship:
(1) 0.20 ≦ JR1 ≦ 0.40
(2) 1.00 ≦ (JR1 / JR2) ≦ 1.40
Definition of region R1:
In the cross-sectional image of the magnetic carrier, two straight lines that are parallel to the maximum length of the line segment A and separated from the line segment A by 2.5 μm are B and C. Assuming a straight line D passing through the intersection of the line segment and the magnetic carrier surface and perpendicular to the line segment, parallel to the straight line D and 5.0 μm away from the magnetic carrier toward the central direction of the magnetic carrier. A region surrounded by the magnetic carrier surface line between the straight lines B and C and the straight lines B, C, and E.
Definition of region R2:
A region surrounded by straight lines B, C, F, and G, where F and G are two straight lines that are parallel to the straight lines D and E and separated from the midpoint of the line segment A by 2.5 μm. The magnetic carrier contains magnetic particles A and magnetic particles B, and the magnetic particles A and B are defined as follows:
The number average particle diameters of the magnetic particles A and B are rA and rB, respectively, and in the cross-sectional image of the magnetic carrier, the ratio of the cross-sectional area of the magnetic particles A to the total magnetic particle cross-sectional area in the R1 region and the R2 region Are AR1 and AR2, respectively, satisfy the following relationship.
(1) 0.30 ≦ rA ≦ 3.00
(2) 0.05 ≦ rB ≦ 0.25
(3) 0.00 ≦ (AR2 / AR1) ≦ 0.50
The magnetic material-dispersed resin carrier according to claim 1, wherein: The magnetic carrier contains magnetic particles A and magnetic particles B, and the magnetic particles A and B are defined as follows:
When the mass ratio (mass%) of the magnetic particles A and B in the magnetic material is wA and wB, respectively, the following relationship is satisfied.
0.51 ≦ wA / (wA + wB) ≦ 0.80
The magnetic material-dispersed resin carrier according to claim 1, wherein:   4. A two-component developer containing a toner containing a binder resin, a colorant, and a release agent, and a magnetic carrier, wherein the magnetic carrier is a magnetic material according to claim 1. A two-component developer, which is a dispersion type resin carrier. In response to a decrease in the toner concentration of the two-component developer in the developing device, a replenishment developer is supplied to the developing device, and the electrostatic latent image formed on the surface of the electrostatic latent image carrier is converted into the two-component developer in the developing device. A developer for replenishment for use in a two-component development method in which development is performed using a system developer and excess magnetic carrier inside the developer is discharged from the developer as necessary.
The replenishment developer contains a replenishment magnetic carrier and a toner containing a binder resin, a colorant, and a release agent, and a toner amount relative to 1 part by mass of the replenishment magnetic carrier is 2 parts by mass or more and 50 masses. The replenishment developer, wherein the replenishment magnetic carrier is the magnetic material-dispersed resin carrier according to any one of claims 1 to 3. A charging step for charging the electrostatic latent image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the surface of the electrostatic latent image carrier, and a two-component developer in the developing device. A developing process for forming a toner image, a transfer process for transferring the toner image to a transfer material with or without an intermediate transfer member, and a fixing process for fixing the transferred toner image to the transfer material. An image forming method comprising:
The image forming method according to claim 4, wherein the two-component developer according to claim 4 is used as the two-component developer.   Image formation that replenishes developer for replenishment as the toner concentration of the two-component developer in the developer decreases, and discharges excess magnetic carrier from the developer as needed The replenishment developer comprises a replenishment magnetic carrier and a toner containing a binder resin, a colorant and a release agent, and the amount of toner relative to 1 part by mass of the replenishment magnetic carrier is 2 parts by mass. The image forming method according to claim 6, wherein the magnetic carrier for replenishment is a magnetic material-dispersed resin carrier according to claim 1, wherein the replenishing magnetic carrier is 50 parts by mass or less. .

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