JP2008224882A - Two-component developer and replenishing developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-component developer and a replenishing developer capable of forming a stable image of high picture quality even for long-term use. <P>SOLUTION: The two-component developer contains toner and magnetic carrier, wherein the toner comprises toner particles containing a binder resin, a colorant, a release agent and a polymer or copolymer having a sulfonic acid group, a sulfonate group or a sulfonic acid ester group, and inorganic fine particles. The magnetic carrier shows such properties that: (i) the carrier comprises composite particles having porous magnetic core particles and a resin component; (ii) the true specific gravity ranges from 2.5 to 4.2 g/cm<SP>3</SP>; (iii) 50%-particle diameter (D50) on the volume basis ranges from 15 to 70 μm; (iv) the average circularity ranges from 0.850 to 0.950, with the change coefficient of the average circularity ranging from 1.0 to 10.0%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a two-component developer for developing an electrostatic image by an electrophotographic method, and more specifically, a two-component developer composed of a sulfonic acid group-containing toner and a magnetic carrier, and a replenishment development. It relates to the agent.

  In the electrophotographic method, the step of developing the electrostatic image is to form an image on the electrostatic image using the electrostatic interaction of the electrostatic image with the charged toner particles. Among the developers for developing electrostatic images using toner, a one-component developer using a magnetic toner in which a magnetic material is dispersed in a resin, and a two-component system in which a non-magnetic toner is mixed with a magnetic carrier There is a developer. In particular, the latter two-component developer is suitably used in a full-color image forming apparatus such as a full-color copying machine or a full-color printer that requires high image quality.

  There are various characteristics required for the magnetic carrier and the toner constituting the two-component developer, but particularly important characteristics for the magnetic carrier include appropriate chargeability, developability, durability against alternating voltage, and resistance to resistance. Examples include impact resistance, wear resistance, and spent resistance.

  In recent years, with the widespread use of high-definition and full-color printers and the like, higher image quality is also desired in electrophotography. However, when an alternating electric field is applied to improve the image quality, if the magnetic carrier has a low resistivity, the latent image potential leaks through the magnetic carrier and a good image cannot be obtained. More than a certain resistivity is required. Therefore, when the magnetic carrier is conductive, a coated magnetic carrier coated with a magnetic carrier coating agent is preferred. In order to bring the resistivity of the magnetic carrier close to an appropriate value, it is considered that the surface of the core material is coated with an insulating resin, and at the same time, the strength of the core is increased, durability and charging stability are improved.

  In addition, the burden on the developer in the developing device tends to increase, such as a reduction in the developer capacity accompanying the downsizing of the developing device and an increase in the developer stirring speed due to an increase in the output speed. The burden on the developer is an impact between magnetic carriers or toners during stirring, and an impact and stress on a developer layer thickness regulating member that causes the developer to have a predetermined layer thickness on the developing sleeve. These are all inevitable steps for imparting proper charge to the toner, and various proposals have been made to reduce this impact. For example, by controlling the shape of the magnetic carrier, the fluidity of the developer is improved and coat peeling is reduced (see Patent Document 1). However, just controlling the shape of the magnetic carrier in this way does not completely satisfy the life of the developer. Furthermore, the concave portion of the magnetic carrier core is filled with a conductive material-added resin to control the lowering of specific gravity and resistance, thereby preventing a long life and magnetic carrier adhesion (see Patent Document 2). However, if the lower layer component of the magnetic carrier coating layer is conductive in this way, image defects due to fogging occur due to durability deterioration. In addition, the magnetic carrier core agent having irregularities is filled with a coating resin to achieve a low specific gravity and smoothness of the fine surface of the magnetic carrier, thereby extending the life of the developer and achieving high image quality (patent) Reference 3).

  On the other hand, in the toner used for the two-component developer, high temperature offset resistance is improved by applying silicone oil or the like to the surface of the fixing member without adding a release agent. However, since excessive silicone oil or the like adheres to the surface of the fixed image obtained in this way, there may be problems such as giving the user an uncomfortable feeling and making the image difficult to see due to uneven gloss. .

  In recent years, the above problem has been suppressed by adding a release agent to the toner due to demands for higher printing speed, higher gloss on the image, and energy saving in the image forming apparatus. When the release agent is added to the toner, the surface of the toner becomes unstable due to the external additive being easily released or buried by rubbing with the carrier, and the charging characteristics change. Will be bigger.

  In order to control the chargeability of the toner, a charge control agent is used. The main charge control agent that is usually used is a compound having a complex structure in which a ligand component is coordinated to a central metal and a charge site. It is roughly classified into two types of polymer compounds containing polar functional groups. Since the compound having a complex structure has crystallinity, the compatibility with the binder resin is poor, and in order to uniformly disperse the toner, the toner manufacturing method may be restricted. On the other hand, since the polymer compound type is easily dispersed with good compatibility with the resin, there are few restrictions on use. As a polymer compound type charge control agent, a resin containing a polymerizable monomer having a specific structure has been proposed in order to stabilize chargeability (see, for example, Patent Document 4).

  As described above, various proposals have been made to extend the life of the developer and achieve high image quality. However, for heavy users who copy a large number of images with a large area, there is a need for a longer life as a developer and a stable charging property, which is not yet complete. Currently. In particular, in the severe environment of high temperature and high humidity and low temperature and low humidity, the present situation is that an optimal combination of carrier and toner constituting the developer is required.

JP-A-8-292607 JP 2002-278165 A JP2003-156877A JP-A 63-184762

  As described above, conventional magnetic carriers and toners still have problems to be improved. In particular, in order to copy a large number of images with a large area in a severe environment of high temperature and high humidity and low temperature and low humidity, 1) durability of developer, 2) charging stability (stability of charging ability to toner) 3) Developability, 4) Further improvement of environmental characteristics, and design with excellent durability characteristics are desired.

  An object of the present invention is to propose a two-component developer and a replenishment developer that solve these problems.

  In order to achieve the above object, the invention according to the present application can be achieved by the following configuration.

(1) A two-component developer having a toner and a magnetic carrier,
The toner includes toner particles containing at least a binder resin, a colorant, a release agent, and a polymer or copolymer having a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group, and at least an inorganic fine powder. A toner having
The magnetic carrier is
i) composite particles containing a resin in the pores of the porous magnetic core particles;
ii) The true specific gravity is 2.5 or more and 4.2 g / cm ³ or less,
iii) The volume-based 50% particle size (D50) is 15 or more and 70 μm or less,
iv) The average circularity is 0.850 or more and 0.950 or less, and the variation coefficient of the average circularity is 1. A two-component developer characterized by being from 0 to 10.0%.
(2) The two-component developer according to (1), wherein the composite particles are coated with a resin coat layer.
(3) The two-component developer according to (1) or (2), wherein the resin component contains a silicone resin.
(4) The two-component developer according to any one of (1) to (3), wherein the resin coat layer contains a silicone resin.
(5) The two-component developer according to any one of (1) to (4), wherein the magnetic carrier contains the resin component and fine particles having a number average particle diameter of 10 to 500 nm.
(6) The circularity measured by the flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is in a circularity range of 0.2 to 1.0. The two-component developer according to any one of (1) to (5), wherein the toner has an average circularity of 0.940 or more and 1.000 or less analyzed by dividing into 800.
(7) Two-component development wherein development is performed while supplying a replenishment developer containing at least toner and a magnetic carrier to the developing device, and at least the excess magnetic carrier inside the developing device is discharged from the developing device as necessary. A replenishing developer for use in a method comprising:
The replenishment developer contains 2 to 50 parts by mass of the toner with respect to 1 part by mass of the magnetic carrier.
The toner includes at least a binder resin, a colorant, a release agent, and toner particles containing a polymer having a functional group selected from the group consisting of a sulfonic acid group, a sulfonic acid group, and a sulfonic acid ester group; A toner having inorganic fine particles;
The magnetic carrier is
i) composite particles having porous magnetic core particles and a resin component;
ii) The true specific gravity is 2.5 or more and 4.2 g / cm ³ or less,
iii) The volume-based 50% particle size (D50) is 15 or more and 70 μm or less,
iv) The average circularity is 0.850 or more and 0.950 or less, and the variation coefficient of the average circularity is 1. A developer for replenishment characterized by being 0 to 10.0% or less.
(8) The replenishment developer according to (7), wherein the composite particles are coated with a resin coat layer.
(9) The developer for replenishment according to (7) or (8), wherein the resin component contains a silicone resin.
(10) The replenishment developer according to any one of (7) to (9), wherein the resin coat layer contains a silicone-based resin.
(11) The replenishment developer according to any one of (7) to (10), wherein the magnetic carrier contains the resin component and fine particles having a number average particle diameter of 10 to 500 nm.
(12) The circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is in a circularity range of 0.2 to 1.0. The toner for replenishment according to any one of (7) to (11), wherein the toner has an average circularity of 0.940 or more and 1.000 or less analyzed by dividing into 800.

  The design of a two-component developer and a replenishment developer that show stable charging ability over a long period of time without deteriorating the developer requires an optimal combination of both the magnetic carrier and the toner.

  That is, according to the present invention, the load on the developer is reduced by controlling the true specific gravity and particle size of the magnetic carrier comprising composite particles containing resin in the pores of the porous magnetic core particles within a specific range. Things will be possible.

  On the other hand, the toner particles contain a polymer or copolymer having a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group that functions as a charging site, so that the toner has a charge imparting ability due to contamination of the carrier surface. Even if it decreases, the charge as a toner is stable, and the charge amount distribution can be sharpened through durability. As a result, a clear image can be obtained from beginning to end.

  By combining these magnetic carriers and toner, good durability, charging stability and developability can be obtained even in severe environments of high temperature and high humidity and low temperature and low humidity. In addition, a change in charge can be suppressed even when left in a harsh environment.

  Furthermore, the use of a replenishment developer composed of toner and a magnetic carrier makes it possible to obtain more excellent characteristics over a long period of time.

In order to solve the problems in the present invention, as a result of intensive studies, the present inventors have obtained a two-component developer having a toner and a magnetic carrier, and the toner includes at least a binder resin, a colorant, a release agent, And a toner having a polymer particle or copolymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group, and at least an inorganic fine powder, wherein the magnetic carrier is i) a porous magnetic core. Composite particles containing a resin in the pores of the particles, ii) True specific gravity is 2.5 or more and 4.2 g / cm ³ or less, iii) Volume-based 50% particle size (D50) is 15 or more and 70 μm or less Iv) The average circularity is 0.850 or more and 0.950 or less, and the coefficient of variation of the average circularity is 1.0 or more and 10.0% or less.・ Durability The present inventors have found that the property and developability can be obtained. Details will be described below.

  First, the magnetic carrier of the present invention will be described.

  The present inventors have examined a magnetic carrier suitable for a two-component developer by paying attention to the spent property, charge imparting ability, and durability stability of the toner and the external additive. As a result, the magnetic carrier is composed of composite particles containing a resin in the pores of the porous magnetic core particles, and the physical properties of the magnetic carrier are such that the true specific gravity and particle size are smaller, the shape is rounder, and the distribution is sharper. It has been found that it exhibits performance suitable for a two-component developer.

  In order to achieve high image quality, it is necessary to have both fine heading and fluidity to faithfully reproduce the latent image, and the toner must be uniformly charged. A magnetic carrier is required.

  Therefore, the volume-based 50% particle size (D50) of the magnetic carrier used in the present invention is preferably 15 or more and 70 μm or less. More preferably, it is 25 or more and 60 micrometers or less, More preferably, it is 30 or more and 55 micrometers or less. When the volume-based 50% particle size (D50) of the magnetic carrier is less than 15 μm, the rising of the developer due to the magnetic force on the developing carrier is not uniform, and the uniformity of the solid image tends to be lost. . Further, the fluidity of the developer is deteriorated and the rising of the charge tends to be deteriorated.

  On the other hand, when the volume-based 50% particle size (D50) of the magnetic carrier exceeds 70 μm, the developer standing due to magnetism is high, and the developer is unevenly swept by the ears, so the image quality tends to deteriorate.

  A magnetic carrier having a volume-based 50% particle size (D50) satisfying the above range can be produced by optimizing the temperature and air amount during granulation.

  When the volume-based 50% particle size (D50) of the magnetic carrier is small, there is a tendency that spent toner and inorganic fine particles are generated on the magnetic carrier due to an increase in contact points between the magnetic carriers and the toner. Furthermore, since the fluidity as a developer is deteriorated by making the magnetic carrier have a small particle diameter, the charge rising tends to be deteriorated. In addition, when the amount of inorganic fine particles is large, carrier adhesion to the latent image carrier may become intense, which not only tends to cause uneven image density, but also disturbs the electrostatic latent image via the carrier. It becomes easy. For this purpose, the inventors have studied paying attention to the shape of the magnetic carrier, and found that the above problems can be solved by rounding the shape and sharpening the shape distribution.

  That is, the average circularity of the magnetic carrier used in the present invention is preferably 0.850 or more and 0.950 or less. More preferably, it is 0.870 or more and 0.930 or less, More preferably, it is 0.880 or more and 0.920 or less. If the average circularity is less than 0.850, it is difficult to obtain desired fluidity, and it is difficult to obtain a good charge rise. On the other hand, if the average circularity is greater than 0.950, the surface area of the magnetic carrier is small, so that sufficient charge imparting properties cannot be obtained, and fog is likely to occur. Further, since the magnetic carrier is nearly spherical, the toner and the magnetic carrier are in point contact, resulting in greater damage to the toner and worsening spent.

  A magnetic carrier whose average circularity satisfies the above range can be produced by increasing the smoothness of the surface of the magnetic carrier with a resin component to be added.

  Further, the coefficient of variation of the average circularity of the magnetic carrier used in the present invention is 1.0 or more and 10.0% or less. More preferably, it is 3.0 or more and 8.0% or less, More preferably, it is 4.0 or more and 7.0% or less. The coefficient of variation is an index indicating the spread of the average circularity distribution of the magnetic carrier. If this coefficient of variation exceeds 10.0%, carrier adhesion tends to occur, and if the coefficient of variation is less than 1.0%, the triboelectric chargeability with the toner deteriorates, so that toner scattering and fog are likely to occur. .

  The magnetic carrier whose average circularity coefficient of variation satisfies the above range can be manufactured by adjusting the amount of the resin component, coating the resin component for the second time, and optimizing the sieve during classification. Is possible.

By reducing the particle size of the magnetic carrier, the number of contact points between the magnetic carrier and the toner or between the carriers also increases, so that spent occurs, and image defects such as image dust tend to occur after durability. Further, it has been found that when the toner concentration is lowered during the durability, the fluidity of the developer is deteriorated and stirring cannot be performed and packing occurs. A countermeasure to this problem is to set the true specific gravity of the magnetic carrier used in the present invention to 2.5 or more and 4.2 g / cm ³ or less.

The specific resistance of the magnetic carrier is preferably 1.0 × 10 ⁷ or more and 1.0 × 10 ¹² Ω · cm or less. When the specific resistance of the carrier is less than 1.0 × 10 ⁷ Ω · cm, the carrier tends to adhere due to the developing bias. On the other hand, if the specific resistance of the carrier exceeds 1.0 × 10 ¹² Ω · cm, it is difficult for the carrier charge to leak, so that the image density is liable to decrease due to the charge-up phenomenon.

  The specific resistance of the carrier can be adjusted by the type of the magnetic material, the pore diameter, the pore distribution, the resin content of the porous magnetic core particles, and the like.

Although details will be described later, it is optimal to adopt an auto-refresh (ACR) developing system from the viewpoint of developer durability. By this method, it is possible to discharge the deteriorated magnetic carrier in the developing machine and replace it with a new magnetic carrier, and it is possible to achieve a long life of the developer. In this ACR development system, it is necessary to replenish magnetic carrier and toner at a constant rate as a replenisher. Therefore, since it is necessary to uniformly disperse the magnetic carrier in the replenisher, the true specific gravity of the magnetic carrier is 2.5 or more and 4.2 g / cm ³ or less. Preferably it is 3.0 or more and 4.0 g / cm < ³ > or less, More preferably, it is 3.0 or more and 3.8 g / cm < ³ > or less. If the true specific gravity of the magnetic carrier is greater than 4.2 g / cm ³ , the specific gravity difference from the toner becomes large, and the magnetic carrier tends to segregate in the replenisher, making it difficult to stably supply the developer. On the other hand, if the true specific gravity of the magnetic carrier is less than 2.5 g / cm ³ , carrier adhesion tends to occur.

In addition, the present inventors have applied a replenisher using a magnetic carrier in which resin is contained in the pores of the porous magnetic core particles and the true specific gravity is adjusted to 2.5 or more and 4.2 g / cm ³ or less to the ACR development system. It has been found that application thereof is excellent in the dispersibility of the magnetic carrier in the replenishment developer. Usually, a replenisher in which a magnetic carrier is contained in a toner has poor fluidity compared to a replenisher containing only toner, and it is difficult to disperse the magnetic carrier. Furthermore, even if the magnetic carrier is uniformly dispersed in the replenishment developer, the magnetic carrier is likely to segregate on the inner wall and the lower part of the replenishment developer container when vibration is applied during the transportation of the replenishment developer container. There was a trend.

The method for adjusting the true specific gravity depends on the composition of the porous magnetic core particles of the magnetic carrier. For example, the true specific gravity of ferrite is about 5.0 g / cm ³ . Therefore, in order to obtain a desired true specific gravity using ferrite, the proportion of the resin component to be contained may be increased. In addition, in ferrite carriers, the surface shape of the ferrite particles can be made any shape from smooth to porous by controlling the degree of sintering growth on the core particle surface during the production of ferrite or using a foaming agent. Is possible.

  As described above, in the magnetic carrier of the present invention, the surface shape of the porous magnetic core particles can be easily controlled, and the desired amount can be obtained by adjusting the amount of the porous magnetic core particles and the resin component. A magnetic carrier having true specific gravity can be obtained.

  Moreover, as the porous magnetic core particles of the magnetic carrier used in the present invention, porous ferrite is preferable because of its excellent productivity. Further, even if the ferrite having a porous shape increases the resin content and lowers the specific gravity, since the resin is impregnated into the pores of the ferrite having a porous shape, the adhesion between the added resin component and the ferrite is preferably increased. The porous ferrite mentioned here means a porous shape having pores inside or on the surface layer. Examples of the production method include lowering the temperature during firing to suppress crystal growth, or adding a pore forming agent such as a foaming agent to generate pores in ferrite. A specific example of a cross-sectional view of a magnetic carrier obtained by adding a resin to the porous ferrite is shown in FIG.

  The foaming agent is not particularly limited as long as it is a substance that generates a gas upon vaporization or decomposition at 60 to 180 ° C. For example, foaming azo polymerization initiators such as azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanecarbonitrile, metal hydrogen carbonates such as sodium and potassium, ammonium hydrogen carbonate, ammonium carbonate, ammonium nitrate , Azide compounds, 4,4′-oxybis (benzenesulfohydrazide), allylbis (sulfohydrazide), diaminobenzene and the like.

  In the present invention, examples of the material of the porous magnetic core particles contained in the magnetic carrier include the following. For example, 1) iron powder with oxidized surface, 2) unoxidized iron powder, 3) metal particles such as lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, chromium and rare earth elements, 4) iron Alloy materials such as lithium, calcium, magnesium, nickel, copper zinc, cobalt, manganese, chromium and rare earth elements, or oxide particles containing these elements, 5) magnetite particles or ferrite particles.

Magnetite or ferrite particles are represented by formula (1).
(Formula 1) (M1 ₂ O) _w (M2O) _x (M3 ₂ O ₃ ) _y (Fe ₂ O ₃ ) _z
(In the formula, M1 is a monovalent metal atom, M2 is a divalent metal atom, M3 is a trivalent metal, w + x + y + z = 1.0, and w, x, and y are each 0. ≦ (w, x, y) ≦ 1.0, and z is 0.2 <z <1.0.)

  In the above formula, as M1 to M3, a metal atom selected from the group consisting of Ni, Cu, Zn, Li, Mg, Mn, Sr, Ca, and Ba can be used.

  For example, there are magnetic Li-based ferrite, Mn-Zn-based ferrite, Mn-Mg-based ferrite, Mn-Mg-Sr-based ferrite, Cu-Zn-based ferrite, Ni-Zn-based ferrite, Ba-based ferrite, and Mn-based ferrite.

  From the viewpoint of easy control of the crystal growth rate, Mn-based ferrite or Mn-Mg-based ferrite containing Mn element is preferable.

  In addition to selecting the type of magnetic material, the specific resistance of the porous magnetic core particles can be adjusted by heat-treating the magnetic particles in an inert gas and reducing the surface of the magnetic particles. For example, the heat treatment can be performed at 600 to 1000 ° C. in an inert gas (eg, nitrogen) atmosphere.

  A well-known method can be employ | adopted for the manufacturing method of the porous magnetic core particle used for this invention. For example, the pulverized ferrite composition is mixed with a binder, water, a dispersant, an organic solvent, etc., and particles are formed using a spray dryer method or a fluidized granulation method, and then 700 or more and 1400 in a rotary kiln or batch-type firing furnace. There can be mentioned a method of firing at a temperature of not higher than ℃, preferably in the range of not lower than 800 and not higher than 1200 ℃, and then classifying by sieving to control the particle size distribution to obtain composite particles for a magnetic carrier. In addition, the surface property of the porous magnetic core particles can be controlled by controlling the oxygen partial pressure in the firing step or adding oxidation / reduction treatment to the surface of the particles after firing.

  The resin component contained in the magnetic carrier is not particularly limited. It is preferable that the porous magnetic core particles have high wettability with respect to the magnetic component, and either a thermoplastic resin or a thermosetting resin may be used. When a resin component having high wettability is used, the surface of the porous magnetic core particle can be easily covered with the resin at the same time when the resin is filled into the pores of the porous magnetic core particle.

  The following are mentioned as a thermoplastic resin. Polystyrene, polymethyl methacrylate, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinyl acetate, polyvinylidene fluoride Resin, fluorocarbon resin, perfluorocarbon resin, solvent-soluble perfluorocarbon resin, polyvinylpyrrolidone, petroleum resin, novolac resin, saturated alkyl polyester resin, polyethylene terephthalate, polybutylene terephthalate, polyarylate aromatic polyester resin, polyamide resin, polyacetal resin, Polycarbonate resin, polyether sulfone resin, polysulfone resin, polyphenylene sulfide resin, polyether ketone resin.

  The following are mentioned as a thermosetting resin. Phenolic resin, modified phenolic resin, maleic resin, alkyd resin, epoxy resin, acrylic resin, unsaturated polyester obtained by polycondensation of maleic anhydride, terephthalic acid and polyhydric alcohol, urea resin, melamine resin, urea-melamine resin , Xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, acetoguanamine resin, gliptal resin, furan resin, silicone resin, polyimide, polyamideimide resin, polyetherimide resin, polyurethane resin.

  Further, a resin obtained by modifying these resins may be used. Among these, a fluorine-containing resin such as polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, or solvent-soluble perfluorocarbon resin, acrylic-modified silicone resin, or silicone resin is preferable because of its high wettability with respect to porous magnetic core particles.

  The silicone resin may be any conventionally known silicone resin. Examples thereof include a straight silicone resin composed only of an organosiloxane bond represented by the following formula, and a silicone resin modified with alkyd, polyester, epoxy, urethane or the like.

In the above formula, R ₁ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, R ₂ and R ₃ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, phenyl Group, an alkenyl group having 2 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a hydroxy group, a carboxyl group, an ethylene oxide group, a glycinyl group, or a group shown below.

In the above formulas, R ₄ and R ₅ are a hydroxy group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, and an alkenyl group having 2 to 4 carbon atoms. An oxy group, a phenyl group, a phenoxy group, k, l, m, n, o, p represents an integer of 1 or more.

  Each of the above substituents may have a substituent such as an amino group, a hydroxy group, a carboxyl group, a mercapto group, an alkyl group, a phenyl group, an ethylene oxide group, or a halogen atom in addition to an unsubstituted group. For example, commercially available straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical Co., Ltd., SR2400 and SR2405 manufactured by Toray Dow Corning Co., Ltd., and modified silicone resins include KR206 (alkyd modified) manufactured by Shin-Etsu Chemical Co., Ltd. Examples thereof include KR5208 (acrylic modification), ES1001N (epoxy modification), KR305 (urethane modification), SR2115 (epoxy modification) and SR2110 (alkyd modification) manufactured by Toray Dow Corning.

  As the resin component, a silicone-based resin is preferably used from the viewpoints of adhesion with the porous magnetic core particles, prevention of spent, and film strength. The silicone resin can be used alone, but is preferably used in combination with a coupling agent. It is also preferable to use a plurality of resins in combination from the viewpoint of improving the adhesion strength of the resin.

  As said coupling agent used suitably, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, etc. are mentioned. Examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-β-. (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxy Silane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, γ Chloropropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane (made by Torre Silicone), allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldi Examples include ethoxysilane, 1,3-divinyltetramethyldisilazane, methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride (manufactured by Chisso Corporation). Of these, aminosilane is preferable.

  By using the aminosilane as the coupling agent, a positively charged amino group can be introduced on the surface of the magnetic carrier, and the toner can be favorably imparted with negative charging characteristics. Furthermore, the presence of the amino group activates both the lipophilic treatment agent preferably treated with the metal compound and the silicone resin. For this reason, a stronger resin layer can be formed by further improving the adhesion of the silicone resin to the porous magnetic core particles and at the same time promoting the curing of the resin.

  The content of the resin component is preferably 3.0 or more and 30.0% by mass or less with respect to the mass of the porous magnetic core particles in order to make the true specific gravity of the magnetic carrier a desired value. More preferably, it is 7.0 or more and 25.0 mass% or less.

  The resin component is preferably a resin layer impregnated inside the porous magnetic core particles. In addition to the resin layer, a resin coat layer may be further provided on the magnetic carrier surface. In that case, the components of the resin layer and the resin coat layer may be the same or different.

The magnetic carrier has a saturation magnetization of 30 to 90 Am ² / kg and an applied magnetic field of 240 kA / m, a residual magnetization of 2 to 20 Am ² / kg and a coercive force of 0.4 to 4.8 kA / m. The following is preferable. The saturation magnetization is more preferably in the range of 58 to 78 Am ² / kg.

When the saturation magnetization exceeds 90 Am ² / kg, the ears on the magnetic brush become hard, and the impact on the developer regulating blade or the like tends to increase during stirring.

Further, when the saturation magnetization is less than 30 Am ² / kg, scattering of magnetic carriers is likely to occur. Further, when the residual magnetization and coercive force deviate from the above values, the transportability of the developer in the developing device tends to become unstable and the durability tends to be inferior.

  The magnetic carrier used in the present invention preferably contains particles in the resin component. By containing particles in the resin component, fine surface irregularities that do not appear as average circularity can be formed on the surface of the magnetic carrier. Due to the unevenness, the toner and the magnetic carrier can be efficiently contacted, and peeling of the resin layer and the coating layer of the magnetic carrier can be suppressed.

  The particles added to the resin layer preferably have a primary number average particle diameter of 10 to 500 nm, and more preferably 50 to 200 nm. When the particles are coated, they have the effect of improving the rising of the toner to form minute irregularities present on the carrier surface. In addition, the presence of unevenness improves the spent resistance, and the durability can be maintained.

  In order to make the primary number average particle diameter within the above range, in the case where the particle granulation method is a pulverization method, it is possible to manufacture by optimizing the pulverization pressure and time. When the granulation method is polymerization, it can be produced by optimizing the polymerization temperature and time.

Examples of the particles include inorganic fine particles of titanium oxide, alumina oxide, and silica fine particles, and resin particles made of a polymer obtained by homopolymerizing or copolymerizing a polymerizable monomer. Examples of the polymerizable monomer include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methoxystyrene, p-ethylstyrene, α-methylstyrene, and p-tertiarybutylstyrene; acrylic Acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, isobutyl acrylate, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, Acrylic esters such as phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylic acid 2- Methacrylic esters such as tilhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc .; other,
Vinyl derivatives, specifically alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, 2-vinylimidazole, N-methyl-2-vinyl Examples thereof include imidazole, N-vinylimidazole, and butadiene. Among these, polymethyl methacrylate (PMMA) and melamine resin are more preferable because they have little change in tribo before and after standing. Known PMMA particles can be used, and materials necessary for the target toner for electrophotographic development can be selected.

  As the granulation method of the resin particles used in the present invention, a method of pulverizing the polymer, a polymerization method such as emulsion polymerization, soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, or the like can be used. The addition amount of the particles is preferably 0.1 to 50.0% by mass with respect to the resin component coated on the magnetic carrier. More preferable effects can be imparted at 1.0 to 45.0 mass%.

  As a method of forming a resin layer on the porous magnetic core particles of the magnetic carrier, it is common to dilute the resin component in a solvent and add it to the porous magnetic core particles. The solvent used here should just be what can melt | dissolve each resin component. When the resin is soluble in an organic solvent, examples of the organic solvent include toluene, xylene, cellosolve butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methanol. In the case of a water-soluble resin component or an emulsion type resin component, water may be used. As a method of adding a resin component diluted with a solvent to the porous magnetic core particles, the resin component is impregnated by a coating method such as an immersion method, a spray method, a brush coating method, a fluidized bed, and a kneading method, Composite particles can be obtained by a method of volatilizing the solvent. The composite particles can be obtained not by a wet method using such a solvent but also by a method in which the surface of the porous magnetic core particles is filled with a resin component powder by a dry method.

  Moreover, you may have a coating (coat) layer in the composite particle obtained above. A coating (coat) layer is formed as a new layer after adding a resin component to porous magnetic core particles. The coating (coat) layer can prevent charge adjustment and deterioration of durability. As a method for forming a coating layer, it is common to dilute the resin component in a solvent and add it. The solvent used here only needs to be able to dissolve each resin component. When the resin is soluble in an organic solvent, as an organic solvent, toluene, xylene, cellosolve butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, In the case of methanol, which is a water-soluble resin component or an emulsion type resin component, water may be used. Examples of the method of adding a resin component diluted with a solvent include a method in which the resin component is applied by an application method such as a dipping method, a spray method, a brush coating method, a fluidized bed, and a kneading method, and then the solvent is volatilized. It is done. In addition, it is also possible to coat | cover the surface of a composite particle with the powder of a resin component by the dry method instead of the wet method using such a solvent.

  When the resin component is coated on the surface of the porous magnetic core particles and then baked, an apparatus of any of the external heating system and internal heating system may be used. Examples of the apparatus include a stationary or fluid electric furnace, a rotary electric furnace, a burner furnace, or a microwave baking apparatus. Although the baking temperature varies depending on the resin component to be used, a temperature equal to or higher than the melting point or glass transition point is necessary, and in the case of a thermosetting resin or a condensation type resin, it is necessary to raise the temperature to a level at which the curing proceeds sufficiently.

  Thus, after the resin component is coated and baked on the surface of the porous magnetic core particles, it is cooled, and a magnetic carrier coated with the resin is obtained through pulverization and particle size adjustment.

  The particles such as the resin particles are preferably present on the surface of the magnetic carrier. In order to make the particles such as the resin particles exist on the surface of the magnetic carrier, it is possible to use a method such as dispersing the particles such as the resin particles in a solvent and dispersing them in the porous magnetic core particles when adding the resin component. It is done. As the solvent to be dispersed at this time, a solvent that does not swell the resin particles is preferably selected.

  Next, the toner of the present invention will be described in detail.

The toner required for the present invention has a circularity measured by a flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) of 0.2 to 1.0. The average circularity analyzed by dividing into 800 in the circularity range is 0.940 or more and 1.000 or less. Preferably it is 0.950 or more and 1.000 or less. A toner having an average circularity of 0.940 or more and 1.000 or less can maintain good developability and transferability from the initial stage to after durable use. In particular, it is preferable that the average circularity of the toner is 0.940 or more and 1.000 or less and the average circularity of the magnetic carrier is 0.850 or more and 0.950 or less in the following points. That is, the toner having the average circularity and the magnetic carrier can hardly damage the toner while maintaining the charge imparting ability of the magnetic carrier to the toner, and can hardly cause the toner to adhere to the magnetic carrier.
.

  The average circularity of the toner is determined by appropriately selecting a method for producing toner particles (for example, selecting a suspension granulation method or an emulsion aggregation method), or by kneading and pulverizing toner particles by a known method (for example, mechanical force or (By using heat).

  The weight average particle diameter D4 of the toner is preferably 4.0 or more and 8.0 μm or less, more preferably 4.0 or more and 7.0 μm or less, and 4.5 or more and 6.5 μm or less. Further preferred. When the weight average particle diameter of the toner is 4.0 or more and 8.0 μm or less, dot reproducibility and transfer efficiency can be sufficiently improved.

  The weight average particle diameter of the toner can be adjusted by classification of the toner particles at the time of production and mixing of classified products.

  Preferred embodiments of the toner of the present invention include the toner of the following first embodiment and the toner of the second embodiment.

  The toner of the first aspect is a toner having toner particles containing a resin mainly composed of a polyester unit and a colorant (hereinafter also referred to as “the toner of the first aspect”). “Polyester unit” refers to a part derived from polyester, and “resin mainly composed of polyester unit” means a resin in which many of the repeating units constituting the resin are repeating units having an ester bond. However, these will be described in detail later.

  The polyester unit is formed by condensation polymerization of ester monomers. Examples of the ester-based monomer include a polyhydric alcohol component and a carboxylic acid component such as a polyvalent carboxylic acid, a polyvalent carboxylic acid anhydride, or a polyvalent carboxylic acid ester having two or more carboxyl groups.

  The following are mentioned as a dihydric alcohol component among a polyhydric alcohol component. Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2. 0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) Bisphenol A alkylene oxide adducts such as -2,2-bis (4-hydroxyphenyl) propane; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 , 4-butanediol, neopentyl glycol, 1,4-butenedio , 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A.

  Examples of the trihydric or higher alcohol component among the polyhydric alcohol components include the following. Sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene.

  The following are mentioned as a carboxylic acid component which comprises a polyester unit. Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or their anhydrides; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or their anhydrides; substituted with an alkyl group having 6 to 12 carbon atoms Succinic acid or anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or anhydrides thereof.

  Preferable examples of the resin having a polyester unit contained in the toner particles of the first aspect include the following. That is, a bisphenol derivative represented by the structure represented by the following formula is used as an alcohol component, and a carboxylic acid component consisting of a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof (eg, fumaric acid, maleic acid). , Maleic anhydride, phthalic acid, terephthalic acid, dodecenyl succinic acid, trimellitic acid, pyromellitic acid) as a carboxylic acid component, and a polyester resin obtained by polycondensing them. This polyester resin has good charging characteristics. The charging characteristics of this polyester resin work more effectively when used as a resin contained in a color toner contained in a two-component developer.

〔式中、Ｒはエチレン基及びプロピレン基から選ばれる１種以上であり、ｘ及びｙはそれぞれ１以上の整数であり、且つｘ＋ｙの平均値は２乃至１０である。〕

[Wherein, R is at least one selected from an ethylene group and a propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10. ]

  A preferred example of the resin having a polyester unit contained in the toner particles of the first aspect includes a polyester resin having a cross-linked site. The polyester resin having a crosslinking site can be obtained by subjecting a polyhydric alcohol and a carboxylic acid component containing a trivalent or higher polyvalent carboxylic acid to a condensation polymerization reaction. Examples of the trivalent or higher polyvalent carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 2,5,7. -Naphthalene tricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and acid anhydrides and ester compounds thereof. The content of the trivalent or higher polyvalent carboxylic acid component contained in the ester-based monomer to be polycondensed is preferably from 0.1 to 1.9 mol% based on the total monomers.

  Further, preferable examples of the resin having a polyester unit contained in the toner particles of the first aspect include (a) a hybrid resin having a polyester unit and a vinyl polymer unit, and (b) a hybrid resin and a vinyl type. A mixture of a polymer, (c) a mixture of a polyester resin and a vinyl polymer, (d) a mixture of a hybrid resin and a polyester resin, and (e) a mixture of a polyester resin, a hybrid resin and a vinyl polymer. It is done.

  The hybrid resin is formed by a transesterification reaction between a polyester unit and a vinyl polymer unit obtained by polymerizing a monomer component having a carboxylic ester group such as an acrylic ester. Examples of the hybrid resin include a graft copolymer or a block copolymer in which a vinyl polymer is a trunk polymer and a polyester unit is a branch polymer.

  The vinyl polymer unit refers to a portion derived from a vinyl polymer. A vinyl polymer unit or a vinyl polymer is obtained by polymerizing a vinyl monomer described later.

  The toner particles of the second aspect of the present invention are toners having toner particles obtained from a direct polymerization method or in an aqueous medium (hereinafter also referred to as “the toner of the second aspect”). The toner particles of the second embodiment may be produced by a direct polymerization method, or may be produced by previously forming emulsified fine particles and then aggregating together with a colorant and a release agent. The toner having toner particles produced by the latter is also referred to as “a toner obtained from an aqueous medium” or “a toner obtained by an emulsion polymerization method”.

  The toner particles of the second embodiment preferably have toner particles obtained by a direct polymerization method or an emulsion polymerization method and having a resin mainly composed of a vinyl resin. The vinyl resin that is the main component of the toner particles is produced by polymerization of a vinyl monomer. The following are mentioned as a vinyl-type monomer. Styrenic monomers, acrylic monomers; methacrylic monomers; monomers of ethylenically unsaturated monoolefins; monomers of vinyl esters; monomers of vinyl ethers; monomers of vinyl ketones; monomers of N-vinyl compounds: other vinyl monomers.

  The following are mentioned as a styrene-type monomer. Styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene .

  The following are mentioned as an acryl-type monomer. Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, dimethylaminoethyl acrylate, acrylic acid Acrylic esters such as phenyl, acrylic acid and acrylic amides.

  Moreover, the following are mentioned as a methacrylic monomer. Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacryl Methacrylic acid esters such as diethylaminoethyl acid and methacrylic acid and methacrylic acid amides.

  Examples of the monomer of the ethylenically unsaturated monoolefins include ethylene, propylene, butylene, and isobutylene.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

  Examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether.

  Examples of the vinyl ketone monomers include vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone.

  Examples of the monomer of the N-vinyl compound include N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, and N-vinyl pyrrolidone.

  Other vinyl monomers include acrylic acid derivatives or methacrylic acid derivatives such as vinyl naphthalenes, acrylonitrile, methacrylonitrile and acrylamide.

  These vinyl monomers can be used alone or in combination of two or more.

  The following are mentioned as a polymerization initiator used when manufacturing a vinyl-type resin. 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis Azo or diazo polymerization initiators such as -4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, Di-t-butyl peroxide, dicyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine Peroxidation Initiator having a system initiator or a peroxide in the side chain; potassium persulfate, such as ammonium persulfate persulfate; hydrogen peroxide.

  Examples of radically polymerizable trifunctional or higher polymerization initiators include tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2-bis (4,4-di-). t-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-amylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane And a radical polymerizable polyfunctional polymerization initiator such as 2,2-bis (4,4-di-t-butylperoxycyclohexyl) butane.

  When the toner of the first aspect and the toner of the second aspect of the present invention are used, both are preferably used in an electrophotographic process that employs oilless fixing. For this reason, the toner particles (the toner of the first aspect and the toner of the second aspect) used in the present invention preferably contain a release agent.

  Examples of the release agent include the following. Low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax, Or block copolymers thereof; waxes mainly composed of fatty acid esters such as carnauba wax, montanic acid ester wax, and behenyl behenate; fatty acid esters such as deoxidized carnauba wax partially or fully deoxidized .

  Suitable release agents include hydrocarbon waxes and paraffin waxes. The toner has one or more endothermic peaks in the temperature range of 30 to 200 ° C. in the endothermic curve of the toner in differential thermal analysis measurement, and the maximum endothermic peak temperature in the endothermic peak is 50 to 110 ° C. In addition, the toner can have good low-temperature fixability and durability.

  The content of the release agent in the toner particles used in the present invention is preferably from 1 to 15 parts by weight, preferably from 3 to 10 parts by weight, based on 100 parts by weight of the binder resin in the toner particles. Is more preferable. When the content of the release agent is 1 to 15 parts by mass, good transferability can be exhibited during oilless fixing.

  The toner particles used in the present invention have a polymer or copolymer having a sulfonic acid group, a sulfonic acid group or a sulfonic acid ester group as a charge control agent.

  By including a sulfone group-containing polymer or copolymer in the toner, even if the carrier surface is contaminated due to durability and the ability to impart charge to the toner is reduced, the triboelectric charge amount of the toner can be increased. For this reason, it is possible to obtain a toner having a stable charge amount through durability.

  By containing the elemental sulfur polymer, the dispersion of the colorant in the toner particles is further promoted, and in addition, the dispersion of a part of the wax due to the dispersion of the colorant is also improved.

  In the present invention, the amount of the residual monomer in the sulfur element-containing polymer is preferably 1000 ppm or less, and more preferably 300 ppm or less. On the other hand, when the residual monomer amount exceeds 1000 ppm, desired charging characteristics cannot be obtained, and it becomes difficult to obtain a stable image density in continuous image output.

  Furthermore, the glass transition point (Tg) of the sulfur element-containing polymer is preferably 50 ° C. or higher and 100 ° C. or lower. More preferably, it is higher than 70 ° C. and 100 ° C. or lower, more preferably 73 ° C. or higher and 100 ° C. or lower. When the glass transition point is less than 50 ° C., the fluidity and storage stability of the toner are inferior and the transferability is also inferior. When the glass transition point exceeds 100 ° C., the fixability at the time of an image having a high toner printing rate is deteriorated.

  As the monomer containing elemental sulfur used for producing the elemental sulfur-containing polymer, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid vinyl Examples thereof include sulfonic acid, methacrylsulfonic acid, and maleic acid amide derivatives, maleimide derivatives, and styrene derivatives having the following structures. Preferred is (meth) acrylamide containing a sulfonic acid group.

  The sulfur element-containing polymer according to the present invention may be a homopolymer of the above monomer, but is preferably a copolymer of the above monomer and another monomer. As the monomer that forms a copolymer with the above monomer, polymerizable monomers such as vinyl aromatic hydrocarbons and (meth) acrylic acid esters are preferably used. More specifically, monomers as exemplified below can be used.

  Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate Acrylates such as methyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; , Ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n -Nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic acid esters such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether, vinyl ethyl ether, vinyl And vinyl ethers such as isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2'-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, Examples include 2,2'-bis (4- (methacryloxy polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylol methanetoteramethacrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.

  The sulfur element-containing polymer preferably contains 0.01 to 20% by mass of a unit derived from a monomer having sulfur element, more preferably 0.05 to 10% by mass, and still more preferably 0.1 to 20% by mass. It is preferable to contain 7 mass%. When the amount is less than 0.01% by mass, the effect of adding the elemental sulfur-containing polymer cannot be sufficiently obtained. When the amount exceeds 20% by mass, a large amount of the element derived from the dispersant of the present invention remains and the fixing property is increased. Is particularly worse.

  There are bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, ionic polymerization, and the like as methods for producing a sulfur element-containing polymer, but solution polymerization is preferable from the viewpoint of operability.

The sulfur element-containing polymer is
X (SO ³⁻ ) n · mY ^{k +}
(X represents a polymer site derived from the polymerizable monomer, Y + represents a counter ion, k is a valence of the counter ion, m and n are integers, and n = k × m. .)
It has the following structure. Counter ions are preferably hydrogen ions, sodium ions, potassium ions, calcium ions, and ammonium ions, and more preferably hydrogen ions.

  The acid value (mgKOH / g) of the sulfur element-containing polymer is preferably 3 or more and 80 or less, more preferably 5 to 40, and still more preferably 10 to 30.

  When the acid value is less than 3, it is difficult to obtain a sufficient charge control action, and the environmental stability tends to be inferior. Conversely, when the acid value exceeds 50, when particles are produced by suspension polymerization using a composition containing such a polymer, the toner particles have an irregular shape, and the circularity is Becomes smaller and the contained release agent appears on the toner surface, which tends to cause a decrease in developability.

  When the sulfur element-containing polymer is contained in an amount of 0.01 to 15.00 parts by mass per 100 parts by mass of the binder resin, the change in toner charge amount is reduced in a wide range of environments from high temperature and high humidity to low temperature and low humidity. This is preferable because it can be performed. More preferably, it is 0.1 to 10.0 parts by mass.

  When the content of the sulfur element-containing monomer is less than 0.01 parts by mass, sufficient charge control action is difficult to obtain, and when it exceeds 15.00 parts by mass, the toner is produced by suspension polymerization. In carrying out, the granulation property is lowered, and developability and transferability are lowered.

  Furthermore, in this invention, it is preferable to contain the unit derived from the monomer which has 0.001 or more and 3.000 mass parts sulfur element per 100 mass parts binder resin. Furthermore, 0.005 or more and 2.000 parts by mass or less, particularly 0.01 or more and 1.500 parts by mass or less are preferable.

  The content of the sulfur element-containing polymer in the toner can be measured using capillary electrophoresis or the like.

  The weight average molecular weight (Mw) of the molecular weight of the sulfur element-containing polymer is preferably from 500 to 100,000. More preferably, it is 1000 or more and 70000 or less, More preferably, it is 5000 or more and 50000 or less. When the weight average molecular weight (Mw) is less than 500, the fluidity of the toner tends to be inferior, and the transferability is lowered. When the weight average molecular weight (Mw) exceeds 100,000, in addition to taking time to dissolve in the monomer, the effect of improving the dispersibility of the pigment is reduced and the coloring power of the toner is reduced.

  The volatile content of the sulfur element-containing polymer is preferably 0.01% or more and 2.00% or less. If the volatile content is less than 0.01%, the volatile content removal process becomes complicated. If the volatile content exceeds 2.00%, charging at high temperature and high humidity, especially charging after standing, may be inferior. become. The volatile matter is the proportion of mass that decreases when heated at a high temperature (135 ° C.) for 1 hour.

  The MELTINDEX value (MI value; g / 10 min) of the sulfur element-containing polymer is preferably from 0.1 to 100.0, more preferably from 0.2 to 80.0. When the MI value is less than 0.1, it becomes difficult to dissolve the resin in the monomer and the monomer system becomes non-uniform, resulting in difficulty in obtaining a toner having a good particle size distribution. When the MI value exceeds 100.0, the resin is too sharp-melted, so that it becomes inferior in blocking resistance when it is made into a toner, and the durability tends to be lowered. The measuring method of MI value is performed based on the A method of JIS standard K7210, and converts a measured value into a 10 minute value.

  When obtaining the physical properties as described above, extraction of the sulfur element-containing polymer from the toner is not particularly limited, and any method can be used.

  The toner particles used in the present invention have a colorant. Here, the colorant may be a pigment or a dye, or a combination thereof.

  Examples of the dye include the following. C. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic green 6.

  Examples of the pigment include the following. Mineral Fast Yellow, Navel Yellow, Naphthol Yellow S, Hansa Yellow G, Permanent Yellow NCG, Tartrazine Lake, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, Fast Violet B, Methyl Violet Lake, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue BC, Chrome Green, Pigment Green B, Malachite Green Lake, Final Yellow green G.

  When the two-component developer of the present invention is used as a developer for forming a full-color image, the toner can contain a magenta color pigment. Examples of the magenta coloring pigment include the following. C. 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, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209, 238, C.I. I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35.

  The toner particles may contain only a magenta color pigment. However, when a dye and a pigment are combined, the clarity of the developer can be improved and the image quality of a full-color image can be improved. Examples of the magenta 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 Disperse Violet 1; 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 include the following. C. I. Pigment Blue 2, 3, 15, 15: 1, 15: 2, 15: 3, 16, 17; I. Acid Blue 6; I. A copper phthalocyanine pigment having 1 to 5 phthalimidomethyl groups substituted on Acid Blue 45 or a phthalocyanine skeleton.

  Examples of the color pigment for yellow include the following. C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 93, 97, 155, 180, C. I. Bat yellow 1, 3, 20

  Examples of the black pigment include carbon powder such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Further, the color may be adjusted by combining a magenta dye and a pigment, a yellow dye and a pigment, a cyan dye and a pigment, and the carbon black may be used in combination.

  The content of the colorant in the toner particles used in the present invention is preferably 1 to 15 parts by mass, and preferably 3 to 12 parts by mass with respect to 100 parts by mass of the binder resin in the toner particles. More preferably, it is 4 or more and 10 parts by mass or less. When the content of the colorant is from 1 to 15 parts by mass with respect to the colorant in the toner particles, transparency is maintained, and in addition, reproducibility of intermediate colors as typified by human skin color is improved. To do. Furthermore, the stability of the charging property of the toner is improved, and a low-temperature fixability can be obtained.

  As a method for producing the toner particles of the first aspect used in the present invention, a pulverization method is preferred in which a binder resin, a colorant, and other internal additives are melt-kneaded, and the kneaded product is cooled and then pulverized and classified. . The toner particles of the second aspect can be produced by a method of directly producing toner particles using a suspension polymerization method, or by an aqueous organic material that is soluble in monomers and insoluble in the resulting polymer. A method for producing toner particles using an emulsion polymerization method represented by a dispersion polymerization method for directly producing toner particles using a solvent or a soap-free polymerization method for producing toner particles by direct polymerization in the presence of a water-soluble polar polymerization initiator And the suspension suspension granulation method and the like are preferable.

  A method for producing toner particles by the pulverization method will be described in detail.

  In the raw material mixing step, a predetermined amount of at least a binder resin, a colorant, and a release agent are weighed and mixed as an internal toner additive. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.

  The toner particle materials blended and mixed as described above are melt-kneaded to melt the binder resin, and the colorant and the like are dispersed therein. In the melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to the advantage of being capable of continuous production. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd. In general, a twin-screw extruder manufactured by Kay Sea Kay, a co-kneader manufactured by Buss, or the like is used.

  The colored resin composition obtained by melt-kneading the raw material of the toner particles is melted and kneaded, rolled with a two-roll or the like, and then cooled through a cooling process such as cooling with water.

  In general, the cooled colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, first, coarse pulverization is performed with a crusher, a hammer mill, a feather mill or the like, and further, pulverization is performed with a kryptron system manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nisshin Engineering Co., Ltd. or the like. After that, if necessary, classification is performed using a classifier such as an inertia class elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.) or a centrifugal class turbo plexer (manufactured by Hosokawa Micron Co., Ltd.). A classified product of 3 to 11 μm is obtained.

  Moreover, it is also possible to perform a spheronization process as surface modification in a surface modification process as needed. For example, the spheronization treatment may be performed using a hybridization system manufactured by Nara Machinery Co., Ltd. or a mechano-fusion system manufactured by Hosokawa Micron Co., Ltd., to obtain a classified product.

  As a preferred method for producing the toner particles used in the present invention, for example, the mechanical modification is not used in the pulverization process, but the powder is pulverized by an air jet pulverizer and then the surface modification using the classification and mechanical impact force shown in FIG. And a method of obtaining a classified product having a weight average particle diameter of 3 to 11 μm using an apparatus that simultaneously performs a quality treatment.

  The batch type surface reforming apparatus shown in FIG. 2 includes a cylindrical main body casing 30, a top plate 43 installed so as to be openable and closable at the top of the main body casing; a fine powder discharge section having a fine powder discharge casing and a fine powder discharge pipe 44. Also, a cooling jacket 31 through which cooling water or antifreeze liquid can be passed; a plurality of square disks 33 on the upper surface, which are attached to the central rotating shaft and are attached to the central rotating shaft as a surface modification means, It has the dispersion | distribution rotor 32 which is a disk-shaped rotary body rotated in the direction at high speed. Furthermore, a liner 34 provided with a large number of grooves on the surface facing the dispersion rotor 32, which is fixedly arranged around the dispersion rotor 32 at a constant interval; fine powder having a predetermined particle size or less in the finely pulverized product, and A classification rotor 35 for continuously removing ultrafine powder; a cold air inlet 46 for introducing cold air into the main body casing 30 is provided. Further, a charging pipe having a raw material charging port 37 and a raw material supplying port 39 formed on the side surface of the main body casing 30 for introducing finely pulverized material (raw material); toner particles after the surface modification treatment are out of the main body casing 30. Product discharge pipe having a product discharge port 40 and a product extraction port 42 for discharging; openable and closable provided between the raw material input port 37 and the raw material supply port 39 so that the surface modification time can be freely adjusted A raw material supply valve 38; and a product discharge valve 41 installed between the product discharge port 40 and the product extraction port 42.

  Next, a method for producing toner particles by the dissolution suspension granulation method will be described in detail.

  The monomer is polymerized in advance, and the polymerization temperature and polymerization time are adjusted so that the desired molecular weight distribution is obtained. Magnetic metal fine particles, a release agent, a colorant, a polymerizable monomer, and a polymerization initiator are added to the obtained polymer. The obtained mixture is suspended by applying a mechanical shear force in the presence of an inorganic or organic dispersant, and then applying heat energy while applying stirring shear to obtain toner particles.

  The toner used in the present invention may be externally added as fine particles. For example, after passing through the pulverization / classification step, a toner having improved fluidity can be obtained by mixing the obtained toner particles with a fluidizing agent or the like with a mixer such as a Henschel mixer.

  The external additive externally added to the toner particle surface preferably contains inorganic fine particles of any one of titanium oxide, alumina oxide, and silica fine particles. Since the externally added inorganic fine particles function as spacer particles for easily separating the toner particles from the magnetic carrier, the average particle size (maximum peak value of the number distribution) is preferably 80 to 200 nm.

  The external additive can contain fine particles having an average particle size (peak value of number distribution) of 50 nm or less in addition to the inorganic fine particles having an average particle size of 80 to 200 nm, thereby improving the fluidity of the toner. Can be made.

  The surface of the inorganic fine particles contained in the external additive is preferably subjected to a hydrophobic treatment. The hydrophobizing treatment is preferably performed by a coupling agent such as various titanium coupling agents and silane coupling agents; fatty acids and metal salts thereof; silicone oils; or a combination thereof.

  Examples of the titanium coupling agent for hydrophobizing the inorganic fine particles contained in the external additive include the following. Tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate.

  Moreover, the following are mentioned as a silane coupling agent. γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ -Aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyl Trimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane.

  Examples of the fatty acid for hydrophobizing the inorganic fine particles include the following. Long chain fatty acids such as undecylic acid, lauric acid, tridecylic acid, dodecylic acid, myristic acid, palmitic acid, pentadecylic acid, stearic acid, heptadecylic acid, arachidic acid, montanic acid, oleic acid, linoleic acid, arachidonic acid. Examples of the metal of the fatty acid metal salt include zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

  Examples of the silicone oil for performing the hydrophobizing treatment include dimethyl silicone oil, methylphenyl silicone oil, and amino-modified silicone oil.

  The hydrophobization treatment is performed by adding 1 to 30% by mass (more preferably 3 to 7% by mass) of a hydrophobizing agent to the inorganic fine particles and coating the inorganic fine particles with respect to the inorganic fine particles. Is preferred.

  The degree of hydrophobicity of the hydrophobized inorganic fine particles is not particularly limited. For example, the methanol wettability of the treated inorganic fine particles is preferably 40 or more and 95 or less. Methanol wettability refers to wettability with methanol.

  The content of the external additive in the toner is preferably 0.1 or more and 5.0% by mass or less, and more preferably 0.5 or more and 4.0% by mass or less. The external additive may be a combination of a plurality of types of fine particles.

  When a two-component developer is prepared in the present invention, a good result is usually obtained when the mixing ratio is 2 to 15% by mass, preferably 4 to 13% by mass, as the toner concentration in the developer. If the toner concentration is less than 2% by mass, the image density tends to decrease, and if it exceeds 15% by mass, fogging and in-machine scattering tend to occur.

  In the present invention, the replenisher may be replenished only with toner or may be replenished with a mixture of toner and magnetic carrier. It is preferable to use a replenishment developer composed of toner and carrier as the replenisher because the durability of the developer is improved and more excellent characteristics are maintained over a long period of time.

  When the replenishment developer is replenished and used, it is necessary to adopt an auto-refresh (ACR) development system in which the excess magnetic carrier inside the developer is discharged from the developer as necessary. It can be replaced with a new magnetic carrier, and the life of the developer can be extended.

  When adjusting the replenishment developer, the magnetic carrier is blended at a ratio of 2 to 50 parts by mass with respect to 100 parts by mass of the toner. The preferable range is 3 to 30 parts by mass of the magnetic carrier with respect to 100 parts by mass of the toner, and the more preferable range is 4 to 20 parts by mass of the magnetic carrier with respect to 100 parts by mass of the toner. Is good. When the mixing ratio of the carrier exceeds 50 parts by mass, the life of the two-component developer is improved, but since the amount of the magnetic carrier is large, when the two-component developer in the developing device is removed, the deterioration is removed. The collecting means for collecting the two-component developer is complicated, which is not preferable. Further, the amount of toner in the replenishment developer container is decreased, the replacement frequency of the replenishment developer container is increased, and not only the load on the user increases but also the cost increases, which is not preferable.

  It is obtained by weighing a predetermined amount of toner for replenishment developer and a magnetic carrier and mixing them with a mixer. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer. Among these, the V-type mixer is preferable in consideration of the dispersibility of the magnetic carrier and the charge rising of the toner.

  The present invention can be used with any image forming apparatus. As an example, an image forming apparatus using a replenishment developer will be described.

  For example, as shown in FIG. 3, the image forming unit group is an image forming unit group in which a plurality of image forming units are arranged in an annular shape. The image forming apparatus includes a moving unit that rotates and moves the entire image forming unit group to sequentially move each of the plurality of image forming units to the single image forming position.

  FIG. 3 is a schematic configuration diagram of an example of an electrophotographic full-color image forming apparatus in which the developing device exchanger 13 and the intermediate transfer member 45 each having a rotary developing unit for each color of the rotary rotation method are mounted. The surface of the electrostatic latent image carrier 1 is uniformly charged to a negative polarity by the charging device 15. Next, the exposure device 14 performs image exposure corresponding to the first color, for example, a yellow image, and an electrostatic latent image corresponding to the yellow image is formed on the surface of the electrostatic latent image carrier 1.

  The developing device exchanger 13 has a rotationally moving configuration, and a schematic configuration diagram is shown in FIG. Before the leading edge of the electrostatic latent image corresponding to the yellow image reaches the developing position, the yellow developing device faces the electrostatic latent image carrier 1, and then the magnetic brush rubs the electrostatic latent image, A yellow toner image is formed on the electrostatic latent image carrier.

  FIG. 4 is a schematic configuration diagram of the developing devices 2, 3, 4, and 5 in FIG.

  As shown in FIG. 4, each developing device used for development includes, for example, a developing sleeve 6 as a developer carrying member, a magnet roller 8, a regulating member 7, developer conveying screws 10 and 11, and a scraper (not shown). Etc. are provided.

  With reference to FIG. 4, the flow of transport until the developer in the developing device is developed will be described. The developing sleeve 6 contains a fixed magnet roller 8 and is driven to rotate with a predetermined developing interval between the developing sleeve 6 and the peripheral surface of the electrostatic latent image carrier 1. The developing sleeve 6 and the electrostatic latent image carrier 1 may be in contact with each other. The regulating member 7 has rigidity and magnetism, and is pressed against the developing sleeve 6 with a predetermined load with no developer interposed therebetween, or is disposed with a predetermined interval between the developing sleeve 6 and the developing member 6. And so on. The pair of developer conveying screws 10 and 11 has a screw structure, conveys and circulates the developer in opposite directions, sufficiently agitates and mixes the toner and the magnetic carrier, and sends the developer as a developer to the developing sleeve 6. Is. The magnet roller 8 is composed of, for example, a magnet having four magnetic poles, such as N poles and S poles alternately arranged at equal intervals, a magnet consisting of six poles, or a portion in contact with the scraper. In order to form a repulsive magnetic field and facilitate the peeling of the developer, one pole may be missing to form five poles, and the developer may be included in a fixed state in the developing sleeve 6.

  The pair of developer conveying screws 10 and 11 also serve as stirring members that rotate in directions opposite to each other, and are supplied from the supply developer container (FIG. 5: 2a, 3a, 4a, and 5a). The replenishment developer to be replenished is conveyed by the thrust of the screw of the agent storage device 9 and the toner and the magnetic carrier are mixed. The homogeneous two-component developer that is triboelectrically charged by the mixing action of the toner and the magnetic carrier is deposited in a layered manner on the peripheral surface of the developing sleeve 6.

  The developer on the surface of the developing sleeve 6 forms a uniform layer by the regulating member 7 provided to face the magnetic pole of the magnet roller 8. The uniformly formed developer layer develops the latent image on the peripheral surface of the electrostatic latent image carrier 1 in the development region, and forms a toner image.

  The toner image is transferred to the intermediate transfer member 45 by the transfer device 40.

  When the yellow copy cycle is completed, the electrostatic latent image carrier 1 that has finished transferring the yellow toner is then subjected to a pre-cleaning process as necessary, and then is neutralized by the static eliminator, and then the cleaning device 18. The yellow toner remaining on the surface is scraped off.

  Then, the developing device 13 is rotated, and the developing devices 3, 4, and 5 are sequentially switched so as to oppose the electrostatic latent image carrier 1, and magenta, cyan, and black toner images are intermediated in the same copy cycle as described above. It is transferred to the transfer body 45.

  When each of the above copy cycles is executed, the toner image for each color component is transferred to the same position on the intermediate transfer body 45 by the transfer device 40, and the toner for each color component is overlaid. One toner image is formed. On the other hand, the transfer material 12 such as paper or transparent sheet accommodated in the paper feed tray 26 is fed one by one to the registration roller 25 by the feed roller 28, and the transfer material 12 is intermediately synchronized with the intermediate transfer body 45. It is conveyed between the transfer body 45 and the transfer roller 43. The transferred transfer material 12 is separated from the intermediate transfer member 45 by the peeling finger 44 after the toner image of the intermediate transfer member 45 is transferred by the transfer roller 43 and introduced into the fixing device 21 by the transfer belt 20. Then, after the toner image is fixed on the transfer material 12, the toner image is discharged to the outside, thereby completing one copy mode. In addition, the surface of the intermediate transfer member 45 having the toner image transferred to the transfer material is neutralized by a neutralization device (not shown), and then the surface is cleaned by the cleaning device 23, and the next copy cycle is awaited.

  When the copying operation as described above is repeated, the toner in the developer stored in the developing tank 17 in the developing device of FIG. 4 is gradually consumed, and the ratio of the toner to the magnetic carrier, that is, the toner concentration is lowered. I will do it. This change in toner density is detected by a toner density sensor (not shown) provided in the developing tank 17, and the toner density is feedback-controlled so that it always falls within an appropriate range necessary for development.

  By the above control, the replenishment developer is discharged from the replenishment developer container to the replenishment developer container 9, and then the replenishment developer is supplied from the replenishment port of the replenishment developer container 9 by the propulsive force of the screw. Is supplied to the developing tank 17 in the developing unit.

  In the auto-refresh development system, the replenishment developer of the present invention in which toner and magnetic carrier are mixed is supplied from the replenishment developer container (2a, 3a, 4a, 5a) to the replenishment developer container 9. A replenishment port is provided and replenished to the developing devices 2, 3, 4, and 5.

  Excess developer discharge from the developing devices 2, 3, 4, and 5 using the rotational movement in the rotating and moving developing device exchanger 13 shown in FIG. 5 will be described with reference to FIGS. .

  In a full-color image forming apparatus including a developing device exchanger 13 having a rotary developing unit adopting a rotational movement method, the developing devices 2, 3, 4, and 5 are rotated and moved inside the developing device exchanger 13 during development. Then, development is performed by rotating to a position facing the electrostatic latent image carrier 1, and rotation is performed to a position not facing the electrostatic latent image carrier 1 during non-development.

  For example, the developer (deteriorated magnetic carrier) that has become excessive at the position where the developing device 5 faces the electrostatic latent image carrier 1 and performs the developing operation causes the developing device 5 provided on the developing device 5 to Overflow from the developer outlet 34. Then, the intermediate developer collection unit 37 and the developer collection auger 36 are moved by the rotation operation, and discharged to the developer collection container 39 provided on the rotation center shaft of the rotary rotation type developing device.

Specifically, the developing method according to the present invention applies an AC voltage to the developing sleeve to form an alternating electric field in the developing area and develops the magnetic brush in contact with the electrostatic latent image carrier 1. It is preferable to carry out. The distance between the developing sleeve 6 and the electrostatic latent image carrier 1 (SD distance) is preferably 100 or more and 1000 μm or less in terms of prevention of magnetic carrier adhesion and improvement in dot reproducibility. If it is narrower than 100 μm, the supply of developer tends to be insufficient, resulting in low image density. If it exceeds 1000 μm, the lines of magnetic force from the magnetic pole S ₁ spread and the density of the magnetic brush decreases, resulting in poor dot reproducibility and magnetic carriers. The restraining force is weakened and magnetic carrier adhesion is likely to occur.

  The voltage between the peaks of the alternating electric field is preferably 300 or more and 3000 V or less, and the frequency is 500 or more and 10,000 Hz or less, which 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 a change in the formation speed of the toner image, it is preferable to perform development by applying a developing bias voltage (intermittent alternating voltage) having a discontinuous AC bias voltage to the developing sleeve. 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 having a well-charged toner, the fog removal voltage (Vback) can be lowered, and the primary charge of the electrostatic latent image carrier can be lowered. The life of the image carrier can be extended. Vback is 200 V or less, more preferably 150 V or less, although it depends on the development system. The contrast potential is preferably from 100 to 400 V so that a sufficient image density is obtained.

  On the other hand, when the frequency is lower than 500 Hz, although related to the process speed, when the toner in contact with the electrostatic latent image carrier is returned to the developing sleeve, sufficient vibration is not applied and fogging is likely to occur. If it exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is likely to deteriorate.

  In the present invention, what is important in the developing method is that a magnetic brush on the developing sleeve 6 and an electrostatic latent image carrier are used in order to develop a sufficient image density, excellent dot reproducibility, and without magnetic carrier adhesion. The contact width with 1 (development contact portion) is preferably 3 or more and 8 mm or less. If the developing contact area is narrower than 3 mm, it is difficult to satisfactorily satisfy the sufficient image density and dot reproducibility. If the developing contact area is larger than 8 mm, developer packing occurs and the operation of the machine is stopped. It becomes difficult to sufficiently suppress adhesion.

  As a method for adjusting the developing contact portion, the distance between the regulating member 7 and the developing sleeve 6 is adjusted, or the distance between the developing sleeve 6 and the electrostatic latent image carrier 1 (the distance between S and D) is adjusted. There is a method of appropriately adjusting the contact width.

  The configuration of the electrostatic latent image carrier may be the same as that of an electrostatic latent image carrier used in a normal 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 used for ordinary photoreceptors. For example, a charge injection layer or a protective layer may be used as the outermost surface layer of the photoreceptor.

  By using the replenishment developer of the present invention, the magnetic carrier replenishment amount from the replenishment developer for auto-refreshing can at least fully exhibit the effects of the present invention such that image quality deterioration can be suppressed. .

  The color laser printer shown in FIG. 6 has a plurality of developing units, and is a quadruple drum system (inline) that obtains a full-color print image by once continuously transferring multiple images onto an intermediate transfer belt 60 that is a second image carrier. ) A printer.

  In FIG. 6, an endless intermediate transfer belt 60 is suspended from a drive roller 6a, a tension roller 6b, and a secondary transfer counter roller 6c, and is rotated in the direction of the arrow in the figure.

  Four developing devices are arranged in series with the intermediate transfer belt 6 in correspondence with each color.

  The photosensitive drum 1 disposed in the developing unit that develops yellow toner is uniformly charged to a predetermined polarity and potential by the primary charging roller 2 during the rotation process. Next, image exposure means (not shown) (color separation / imaging exposure optical system for color original image, scanning exposure system by laser scanning that outputs a laser beam modulated in accordance with time-series electric digital pixel signals of image information, etc.) By receiving the image exposure 3 according to the above, an electrostatic latent image corresponding to the first color component image (yellow component image) of the target color image is formed.

  Next, the electrostatic latent image is developed with yellow toner, which is the first color, by a first developing device (yellow developing device).

  In FIG. 6, the yellow image formed on the photosensitive drum 1 enters the primary transfer nip portion with the intermediate transfer belt 6. In the transfer nip portion, the flexible electrode 63 is brought into contact with the back side of the intermediate transfer belt 6. Each developing device has a primary transfer bias source 63 so that the flexible electrode 63 can be biased independently at each port. The intermediate transfer belt 6 first transfers yellow at the port of the first color, and then performs multiple transfer of each color of magenta, cyan, and black sequentially from the photosensitive drum 1 corresponding to each color through the same process described above.

  The four-color full-color image formed on the intermediate transfer belt 6 is then collectively transferred to the transfer material P by the secondary transfer roller 8 and melted and fixed by a fixing device (not shown) to obtain a color print image.

  The secondary transfer residual toner remaining on the intermediate transfer belt 6 is subjected to blade cleaning by the intermediate transfer belt cleaner 9 to prepare for the next image forming process.

  In selecting the material of the transfer belt 6, in order to improve registration at each color port, a material that expands and contracts is not desirable, and a resin-based or rubber core with a metal core, or a resin + rubber belt is desirable.

  The auto-refresh development method that can be used in the present invention will be described with reference to FIGS.

In the developing operation of the developing device 4 of FIG. 6 and 7 using the auto-refresh developing system, replenishing developer obtained by mixing a toner and a magnetic carrier, the replenishing developer storage chamber R _3, and f the supply opening 20 Then, the developing device 4 is replenished.

  When the developing operation is repeatedly performed, the excess developer (deteriorated magnetic carrier) overflows from the developer-side developer discharge port 34 provided in the developing device 4, and from the developer intermediate recovery chamber 35, The developer collection auger 36 is discharged into a developer collection container (not shown).

  Below, the suitable measuring method of physical properties, such as a material used for this invention, is demonstrated.

  When measuring the physical properties of the magnetic carrier from the replenishment developer and the two-component developer, the developer is washed with ion-exchanged water containing 1% of a surfactant (preferably alkylbenzenesulfuric acid hydrochloride), and the toner and the magnetic carrier. The measurement is carried out after separation.

<Measurement method of true specific gravity of magnetic carrier>
The true specific gravity of the magnetic carrier used in the present invention can be determined by a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). This measurement method measures the true density of a solid / liquid based on a gas phase substitution method. Similar to the liquid phase replacement method, it is based on Archimedes' principle, but uses a gas as a replacement medium, and is therefore characterized by high accuracy for micropores.

<Measuring method of particle size of magnetic carrier>
The particle size of the carrier is measured by a laser diffraction particle size distribution analyzer SALD-300V (manufactured by Shimadzu Corporation), and a volume-based 50% particle size (D50) is calculated.

<Measurement method of primary number average particle diameter of particles in resin component covering magnetic carrier core>
Processing observation was performed using a focused ion beam processing observation apparatus (FIB) and FB-2000C (Hitachi, Ltd.). For the preparation of the sample, a carbon paste aqueous solution is applied to the sample stage, and a small amount of the sample (carrier) is placed thereon. Thereafter, the sample is set in the FIB apparatus without performing platinum vapor deposition, and the surface of the target sample is irradiated with the beam. Thereby, the convex part resulting from particle | grains can be observed. The diameter of the convex part is measured. This measurement was carried out by extracting 3 locations from 20 randomly extracted carrier cross-sectional photographs, a total of 60 locations, and calculating the average value thereof as the primary number average particle size of the particles.

<Measurement method of magnetic carrier concentration in replenishment developer>
After washing 5 g of the developer for replenishment with ion exchange water containing 1% of Contaminone N (surfactant), separating the toner from the magnetic carrier, drying and humidity control (25.0 ° C./60% RH) )did. Thereafter, the concentration of the magnetic carrier in the replenishment developer was calculated by calculating the mass of the magnetic carrier contained in the replenishment developer.

<Measurement method of volume resistivity of particles>
The sample is formed into a tablet using the apparatus shown in FIG. First, about 0.3 g of a sample is placed in a tablet molding chamber. Next, the push rod 42 is inserted into the tablet molding chamber and pressurized by a hydraulic pump 45 at 250 kg / cm ² for 5 minutes to mold a pellet-shaped tablet having a diameter of about 13 mm and a height of about 2 to 3 mm. The tablets obtained here are coated with a conductive agent on the front and back surfaces as necessary, for example, using a 16008A RESISTIVITYCELL manufactured by HEWLETT PAKAARD; The resistance value when a voltage of 1000 V is applied is measured under the following conditions, and the specific electric resistance value ρ is obtained by the following calculation formula (8).

(Formula 8)
ρ (Ω · cm) = R (Ω) × S (cm ² ) / l (cm)
(In the formula, S represents the cross-sectional area of the sample, and l represents the height of the sample)

<Measuring method of average circularity and coefficient of variation of magnetic carrier>
The average circularity and coefficient of variation of the magnetic carrier and the magnetic carrier core were calculated as follows using a multi-image analyzer (trade name: Multisizer, manufactured by Beckman Coulter, Inc.).

  The multi-image analyzer is a combination of a particle size distribution measuring apparatus based on an electrical resistance method and a function of photographing a particle image with a CCD camera and a function of analyzing the photographed particle image. Specifically, when the particles uniformly dispersed by an ultrasonic wave or the like in the electrolyte solution pass through the aperture of the multisizer, the multisizer detects a change in electric resistance, and synchronizes the strobe. An image of the particle is taken with a CCD camera by emitting light. This particle image is taken into a personal computer, binarized, and then subjected to image analysis.

  This device has various shapes such as average circularity, unevenness, aspect ratio, envelope perimeter and perimeter length ratio, as well as particle diameter data of equivalent circle diameter, longest diameter, area, sphere equivalent diameter from the above particle image. Can be analyzed. Furthermore, since the sample introduction method is a continuous method, even a magnetic carrier that has a high specific gravity and easily settles and is difficult to disperse in a solution can be measured with good reproducibility.

  The average circularity is represented by the following (formula 9-2). The closer it is to a circle, the closer it is to 1; The average circularity is calculated by adding the circularity of each particle and dividing by the total number of particles. The coefficient of variation can be obtained by the following (formula 9-3).

(Formula 9-1)
Circularity = (4 × area) / (maximum length) ² × π

(Formula 9-2)

(Formula 9-3)

  The specific measurement method is as follows. A solution obtained by mixing about 1% NaCl aqueous solution and glycerin at 50% by volume: 50% by volume is used as the electrolytic solution. Here, the NaCl aqueous solution may be prepared using primary sodium chloride, and may be, for example, ISOTON (registered trademark) -II (manufactured by Coulter Scientific Japan). Glycerin may be a special grade or first grade reagent.

  To the electrolytic solution (about 30 ml), 0.1 to 1.0 ml of a surfactant (preferably alkylbenzenesulfone hydrochloride) as a dispersant is added, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 minute with an ultrasonic disperser to obtain a dispersion.

  The electrolytic solution and the dispersion liquid are put into a glass measuring container, and the concentration of carrier particles in the measuring container is set to 5 or more and 10% by volume or less. Stir the contents of the glass measuring container at the maximum stirring speed. The sample suction pressure is 10 kPa. When the carrier specific gravity is large and sediments easily, the measurement time is 15 to 30 minutes. Further, the measurement is interrupted every 5 to 10 minutes to replenish the sample solution and the electrolytic solution-glycerin mixed solution.

  A 200 μm aperture and a 20 × lens are used for taking a particle image. As measurement conditions, the average luminance within the measurement frame is set to 220 to 230, the measurement frame setting is set to 300, and the binarization level is set to 180.

  A strobe is emitted with a pulse of electrical resistance change when particles pass through the aperture as a trigger, and a particle image is taken with a CCD camera. A threshold (SH) value is set for the threshold of this pulse. The basic value of this SH value is set to 50, but it is necessary to make it an optimum value depending on the state of the sample. The optimum value is confirmed by the magnitude of the blur of the particle image to be photographed. As a guideline, the measurement was performed by setting the imaging speed of the particle image to be 10 or more / 20 or less.

  The particle image is taken into a personal computer, binarized, and then analyzed. The number of measurements is 2000. After the measurement is finished, the main body software removes the defocused image and aggregated particles (multiple simultaneous measurements) on the particle image screen. Through image analysis, particle size data of the equivalent circle diameter, longest diameter, area, and sphere equivalent diameter of the particles and particle shape data of average circularity, unevenness, aspect ratio, envelope perimeter to perimeter length ratio are obtained.

<Method for measuring weight average particle diameter of toner>
In the present invention, Coulter Multisizer (manufactured by Beckman Coulter, Inc.) was used for the weight average particle size (D4) and particle size distribution of the toner. As the electrolytic solution, a 1% NaCl aqueous solution was prepared using first grade sodium chloride. For example, ISOTON R-II can be used as the electrolytic solution.

  A surfactant, preferably alkylbenzene sulfonate, was added in an amount of 0.1 to 5 ml as a dispersant in the electrolytic aqueous solution 100 to 150 ml, and 2 to 20 mg of a measurement sample was further added.

  The electrolytic solution in which the measurement sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and provided to the measurement apparatus using an aperture tube diameter of 100 μm. The volume and number distribution of toner of 2.00 μm or more were measured to calculate the volume distribution and the number distribution, and the weight average particle diameter (D4) (the median value of each channel is the representative value for each channel) was obtained.

  The channel is 2.00 or more and less than 2.52 μm; 2.52 or more and less than 3.17 μm; 3.17 or more and less than 4.00 μm; 4.00 or more and less than 5.04 μm; 5.04 or more and less than 6.35 μm; 6 35 to 8.00 μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm 13 channels of 25.40 or more and less than 32.00 μm; 32.00 or more and less than 40.30 μm were used.

<Measurement method of triboelectric charge amount of toner>
FIG. 9 shows a schematic diagram of an apparatus for measuring the triboelectric charge amount. About 0.5 to 1.5 g of a two-component developer collected from the developing sleeve of a copying machine or printer was placed in a metal measuring container 272 having a 500-mesh screen 273 at the bottom, and a metal lid 274 was placed. . The mass of the entire measurement container 272 at this time was weighed and used as W1 (g). Next, in the suction machine 271 (at least the part in contact with the measurement container 272 is an insulator), the pressure of the vacuum gauge 275 is set to 250 mmAq by suction from the suction port 277 and adjusting the air volume control valve 276. In this state, suction was sufficiently performed, preferably for 2 minutes, and the toner was removed by suction. The potential of the electrometer 279 at this time was set to V (volt). Here, 278 is a capacitor, and the capacity is C (mF). Moreover, the weight of the whole measurement container after aspiration was weighed and set to W2 (g). The triboelectric charge amount (mC / kg) of this sample was calculated as shown below (Formula 10).

(Formula 10)
Sample triboelectric charge (mC / kg) = C × V / (W1-W2)
(However, the measurement conditions are 23 ° C. and 60% RH)

<Measuring method of average circularity of toner>
The average circularity of the toner particles was measured with a flow type particle image analyzer “FPIA-3000 type” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during the calibration operation.

  As a specific measurement method, an appropriate amount of a surfactant, preferably an alkyl benzene sulfonate, is added to 20 ml of ion-exchanged water, and then 0.02 g of a measurement sample is added, and an oscillation frequency of 50 kHz and an electric output of 150 W is added. Dispersion treatment was carried out for 2 minutes using a desktop type ultrasonic cleaner / disperser (for example, “VS-150” (manufactured by VervoCrea Co., Ltd.)) to obtain a dispersion for measurement. It cools suitably so that it may become 10 to 40 degreeC.

  The flow type particle image analyzer equipped with a standard objective lens (10 ×) was used for the measurement, and a particle sheath “PSE-900A” (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, 3000 toner particles are measured in the total count mode in the HPF measurement mode, and the binarization threshold at the time of particle analysis is 85%. The analysis particle diameter was limited to a circle equivalent diameter of 2.00 μm or more and 200.00 μm or less, and the average circularity of the toner particles was obtained.

  In the measurement, automatic focus adjustment is performed using standard latex particles (for example, Duke Scientific 5200A diluted with ion-exchanged water) before the measurement is started. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In this embodiment, a flow type particle image analyzer which has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, has an analysis particle diameter of 2.00 μm in equivalent circle diameter. The measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that it was limited to 200.00 μm or less.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

<Example of magnetic carrier production>
(Method for producing magnetic core particle 1)
As a ferrite component, 28.0 mol% MnO, 3.0 mol% MgO, 68.0 mol% Fe ₂ O ₃ and 1.0 mol% SrCO ₃ were pulverized, mixed and dried in a wet ball mill for 5 hours. The obtained dried product was held at 800 ° C. for 3 hours and pre-baked. This temporarily fired product was pulverized with a wet ball mill for 8 hours to 2 μm or less. To this slurry, 2.0% by mass of binder (polyvinyl alcohol) and 1.0% by mass of sodium hydrogen carbonate as a pore adjuster were added. Next, the mixture was granulated and dried with a spray dryer (manufacturer: Okawara Chemical Industries Co., Ltd.) to obtain a granulated product having a volume-based 50% particle size (D50) of about 50 μm. This granulated product was put in an electric furnace, and held at 1200 ° C. for 3 hours in a mixed gas in which the oxygen concentration in nitrogen gas was adjusted to 2.0 vol%, and then subjected to main firing. The obtained main firing was crushed and further sieved with a sieve (aperture 75 μm) to obtain a magnetic core particle 1 having a volume-based 50% particle size (D50) of 52 μm. When the surface of the magnetic core particle 1 was observed with an SEM, pores were observed.

(Method for producing magnetic core particle 2)
As a ferrite component, 22.0 mol% MgO, 58.0 mol% Fe ₂ O ₃ and 20.0 mol% SrCO ₃ were pulverized in a wet ball mill for 5 hours, mixed and dried. The obtained dried product was held at 800 ° C. for 3 hours and pre-baked. This temporarily fired product was pulverized with a wet ball mill for 8 hours to 2 μm or less. To this slurry, 1.5% by weight of binder (polyvinyl alcohol) and 3.0% by weight of sodium hydrogen carbonate as a pore adjuster were added. Next, the mixture was granulated and dried with a spray dryer (manufacturer: Okawara Chemical Industries Co., Ltd.) to obtain a granulated product having a volume-based 50% particle size (D50) of about 35 μm. The granulated product was put in an electric furnace, and held in a mixed gas in which the oxygen concentration in nitrogen gas was adjusted to 2.0 vol% at 1000 ° C. for 3 hours to perform main firing. The obtained main firing was crushed and further sieved with a sieve (aperture 75 μm) to obtain magnetic core particles 2 having a volume-based 50% particle diameter (D50) of 38 μm. When the surface of the magnetic core particle 2 was observed with an SEM, a larger number of pores than the magnetic core particle 1 were observed.

(Method for producing magnetic core particles 3 and 4)
After sieving with a sieve, magnetic core particles 3 and 4 were obtained in the same manner as magnetic body 2 except that the particle size was adjusted by air classification (elbow jet: manufactured by Nittetsu Mining Co., Ltd.). A volume-based 50% particle size (D50) of 38 μm and a sharper particle size distribution than the magnetic core particle 2 were obtained.

(Method for producing magnetic core particle 5)
The magnetic core particle 5 was obtained in the same manner as the magnetic core particle 2 except that the granulation and sieving conditions by the spray dryer were changed to change the volume-based 50% particle size (D50) to 69 μm.

(Method for producing magnetic core particle 6)
The magnetic core particle 6 was obtained in the same manner as the magnetic core particle 1 except that the granulation and sieving conditions were changed by a spray dryer so that the volume-based 50% particle size (D50) was 13 μm.

(Method for producing magnetic core particle 7)
The ferrite component is changed to 4.0 mol% BaO, 11.0 mol% NiO, 25.0 mol% ZnO, 60.0 mol% Fe ₂ O ₃ and the temperature of the main firing is set to 1200 ° C. In the same manner as the magnetic body 1, magnetic core particles 7 were obtained. When this magnetic core particle 7 was observed with an SEM, holes were observed on the surface of the magnetic material, but a large number of irregular shapes were observed.

(Method for producing magnetic core particle 8)
As a ferrite component, 55.0 mol% LiO and 45.0 mol% Fe ₂ O ₃ were pulverized in a wet ball mill for 5 hours, mixed and dried. The obtained dried product was held at 1000 ° C. for 3 hours and calcined. This temporarily fired product was pulverized with a wet ball mill for 8 hours to 2 μm or less. A 1.5% by weight binder (polyvinyl alcohol) is added to the slurry, and then granulated and dried with a spray dryer (manufacturer: Okawahara Chemical), and the volume-based 50% particle size (D50) is about 55 μm. I got a product. This granulated product was put in an electric furnace, and held at 1500 ° C. for 3 hours in a mixed gas in which the oxygen concentration in nitrogen gas was adjusted to 2.0 vol%, followed by firing. The obtained fired product was crushed and sieved with a sieve (aperture 75 μm) to obtain magnetic core particles 8 having a volume-based 50% particle size (D50) of 59 μm. When the surface of the magnetic core particle 8 was observed with an SEM, no groove on the core surface was seen, and the surface property was smooth.

<Example of manufacturing magnetic carrier>
(Method for manufacturing magnetic carrier 1)
Straight silicone resin (KR255 (solid content conversion) manufactured by Shin-Etsu Chemical Co., Ltd.): 100 parts by mass Silane coupling agent (γ-aminopropylethoxysilane): 8 parts by mass Carbon black (CB)
(Number average particle diameter 30 nm, DBP oil absorption 50 ml / 100 g): 8 parts by mass The above components were mixed with 300 parts by mass of xylene to obtain a magnetic carrier resin-added solution. While stirring this resin addition solution using a fluidized bed heated to 70 ° C., the magnetic core particles 1 were added and the solvent was added so that the mass of the straight silicone resin was 15.0% by mass with respect to the mass of the magnetic material. A removal operation was performed. Furthermore, after performing the process for 3 hours at 200 degreeC using oven, the crushing and the classification process by a sieve (aperture 75 micrometers) were performed, and the magnetic carrier 1 was obtained. The constituent materials and physical properties of the magnetic carrier 1 are shown in Table 1.

(Method for manufacturing magnetic carriers 2 and 3)
Magnetic carriers 2 and 3 were obtained in the same manner as the magnetic carrier 1 except that the amount of the resin component added to the magnetic core particles 1 was changed. Table 1 shows constituent materials and physical properties of the magnetic carriers 2 and 3.

(Method for producing magnetic carriers 4, 5, 6)
Magnetic carriers 4, 5, and 6 were obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 2 were used and the amount of the resin component added to the magnetic material was changed. Table 1 shows the constituent materials and physical properties of the magnetic carriers 4, 5, and 6.

(Method for manufacturing magnetic carrier 7)
A magnetic carrier 7 was obtained in the same manner as the magnetic carrier 1 except that the magnetic core particle 3 was used and the amount of the resin component added to the magnetic material was changed. The constituent materials and physical properties of the magnetic carrier 7 are shown in Table 1.

(Method for manufacturing magnetic carrier 8)
A magnetic carrier 8 was obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 4 were used and the amount of the resin component added to the magnetic material was changed. The constituent materials and physical properties of the magnetic carrier 8 are shown in Table 1.

(Method for producing magnetic carriers 9, 10)
Magnetic carriers 9 and 10 were obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 5 were used and the amount of the resin component added to the magnetic material was changed. Table 1 shows constituent materials and physical properties of the magnetic carriers 9 and 10.

(Method for manufacturing magnetic carriers 11 and 12)
Magnetic carriers 11 and 12 were obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 6 were used and the amount of the resin component added to the magnetic material was changed. Table 1 shows the constituent materials and physical properties of the magnetic carriers 11 and 12.

(Method for manufacturing magnetic carrier 13)
A magnetic carrier 13 was obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 7 were used and the amount of the resin component added to the magnetic material was changed. The constituent materials and physical properties of the magnetic carrier 13 are shown in Table 1.

(Method for producing magnetic carrier 14)
A magnetic carrier 14 was obtained in the same manner as the magnetic carrier 1 except that the magnetic core particles 8 were used and the amount of the resin component added to the magnetic material was changed. Table 1 shows the constituent materials and physical properties of the magnetic carrier 14.

(Method for manufacturing magnetic carrier 15)
Straight silicone resin (KR255 manufactured by Shin-Etsu Chemical Co., Ltd. (solid content conversion)): 100 parts by mass Silane coupling agent (γ-aminopropylethoxysilane): 8 parts by mass Carbon black (number average particle size 30 nm, DBP oil absorption (Amount 50ml / 100g)
: 8 parts by mass-polymethyl methacrylate resin particles (MP300 manufactured by Soken Chemical Co., Ltd., number average particle size 150 nm): 15 parts by mass The above components were mixed with 300 parts by mass of xylene to obtain a magnetic carrier resin addition solution. While stirring the resin coating solution using a fluidized bed heated to 70 ° C., the magnetic core particles 2 were added and the solvent so that the mass of the straight silicone resin was 15.0% by mass with respect to the mass of the carrier core. A removal operation was performed. Furthermore, after processing for 3 hours at 200 ° C. using an oven, pulverization and classification with a sieve (aperture 75 μm) were performed to obtain a magnetic carrier 15. Table 1 shows the constituent materials and physical properties of the magnetic carrier 15.

(Method for manufacturing magnetic carriers 16 and 17)
Magnetic carriers 16 and 17 were obtained in the same manner as the magnetic carrier 11 except that the additive particles and the particle sizes of the additive particles shown in Table 1 were used. The constituent materials and physical properties of the magnetic carriers 16 and 17 are shown in Table 1.

(Method for manufacturing magnetic carrier 18)
-Straight silicone resin (KR255 manufactured by Shin-Etsu Chemical Co., Ltd. (in terms of solid content)): 100 parts by mass-Silane coupling agent (γ-aminopropylethoxysilane): 10 parts by mass The above components are mixed with 300 parts by mass of xylene. A magnetic carrier resin addition solution was used. While stirring this resin coating solution using a fluidized bed heated to 70 ° C., the carrier core 2 was added and the solvent was added so that the mass of the straight silicone resin was 6.0% by mass with respect to the mass of the magnetic carrier core. A removal operation was performed. Furthermore, after performing the process for 3 hours at 200 degreeC using oven, the crushing and the classification process by a sieve (aperture 75 micrometers) were performed, and the magnetic carrier 18 was obtained. Table 1 shows the constituent materials and physical properties of the magnetic carrier 18.

(Method for manufacturing magnetic carrier 19)
Magnetic carrier 18: 100 parts by mass Toluene: 15 parts by mass cyclohexyl methacrylate-methyl methacrylate (CHMA-MMA) copolymer (component ratio 50:50): 5 parts by mass Carbon black (Regal 330; manufactured by Cabot Corporation): 1 part by mass

  The above components except for the magnetic carrier 18 were stirred / dispersed with a stirrer for 90 minutes to prepare a coating layer forming raw material solution. Next, this raw material solution and the magnetic carrier 19 were put into a vacuum degassing type neater, stirred at 60 ° C. for 60 minutes, further degassed while being heated, degassed, and dried to obtain a magnetic carrier 19. . Table 1 shows the constituent materials and physical properties of the magnetic carrier.

(Method for manufacturing magnetic carrier 20)
Magnetic carrier 18: 100 parts by mass Toluene: 15 parts by mass Styrene-methacrylate copolymer (component ratio 90:10): 2 parts by mass Carbon black (Regal 330; manufactured by Cabot): 1 part by mass Polyacrylic acid Methyl resin particles (MP300 manufactured by Soken Chemical Co., Ltd., number average particle size 150 nm): 1.5 parts by mass

  The above components except for the magnetic carrier 18 were stirred / dispersed with a stirrer for 90 minutes to prepare a coating layer forming raw material solution. Next, the raw material solution and the magnetic carrier 18 were put into a vacuum degassing type neater, stirred at 60 ° C. for 60 minutes, further degassed while being heated, degassed, and dried to obtain a magnetic carrier 20. . The constituent materials and physical properties of the magnetic carrier 20 are shown in Table 1.

  Next, an example of toner production will be shown.

  First, an example of producing a polar polymer will be shown first.

  In a pressurizable reaction vessel equipped with a reflux tube, a stirrer, a thermometer, a nitrogen introduction tube, a dropping device and a decompression device, methanol: 250 parts by mass, 2-butanone: 140 parts by mass, and 2-propanol: 110 parts by mass, styrene: 85 parts by mass, acrylic acid-2-ethylhexyl: 8 parts by mass, 2-acrylamido-2-methylpropanesulfonic acid: 7 parts by mass were added as monomers, and the mixture was heated to reflux temperature while stirring. A solution obtained by diluting 1 part by mass of t-butylperoxy-2-ethylhexanoate as a polymerization initiator with 20 parts by mass of 2-butanone was added dropwise over 30 minutes, and stirring was continued for 6 hours. Further, a solution obtained by diluting 1 part by mass of t-butylperoxy-2-ethylhexanoate with 20 parts by mass of 2-butanone was added dropwise over 30 minutes, and the mixture was further stirred for 6 hours to complete the polymerization. Further, 500 parts by mass of deionized water was added while maintaining the temperature, and the mixture was stirred at 80 to 100 revolutions per minute for 2 hours so that the interface between the organic layer and the aqueous layer was not disturbed, and then allowed to stand for 30 minutes and separated. After layering, the aqueous layer was discarded, and anhydrous sodium sulfate was added to the organic layer for dehydration.

  Next, the polymer obtained after distilling off the polymerization solvent from the organic layer under reduced pressure was coarsely pulverized to 100 μm or less using a cutter mill equipped with a 150 mesh screen. The obtained polar polymer had a Tg of about 75 ° C. The obtained polar polymer is designated as polar polymer 1.

(Toner Production Example 1)
As monomers or dimers for vinyl copolymer units, styrene 2.1 mol, 2-ethylhexyl acrylate 0.23 mol, fumaric acid 0.15 mol, α-methylstyrene dimer 0.02 mol, a crosslinking agent and As a polymerization initiator, 0.10 mol of dicumyl peroxide is put into a dropping funnel. Moreover, 7.0 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis ( 4-hydroxyphenyl) propane (3.0 mol), terephthalic acid (3.0 mol), trimellitic anhydride (1.5 mol), fumaric acid (5.0 mol) and dibutyltin oxide (0.2 g) were placed in a glass 4-liter four-necked flask and the temperature A meter, a stirring bar, a condenser, and a nitrogen inlet tube were installed and placed in a mantle heater. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually increased while stirring, and while stirring at a temperature of 145 ° C., the monomer of the vinyl resin, the crosslinking agent and the polymerization initiator were added from the previous dropping funnel. It was dripped over 5 hours. Next, the temperature was raised to 200 ° C. and reacted for 5 hours to obtain Resin 1.

-Resin 1: 100 parts by mass-Wax (normal paraffin, maximum endothermic peak temperature measured by differential scanning calorimeter (DSC): 75 ° C): 5 parts by mass-Polar polymer 1: 1.5 parts by mass- 1,4-di-t-butylsalicylic acid aluminum compound: 0.7 parts by mass / cyan pigment (Pigment Blue 15: 3): 4 parts by mass Preliminarily mixed with a Henschel mixer with the above formulation, and twin-screw extrusion kneader The material was melt kneaded at a material temperature of 130 ° C. After cooling, it was coarsely pulverized to about 1 to 2 mm or less using a hammer mill, and then finely pulverized to a particle size of 15 μm or less with an air jet fine pulverizer. Further, the obtained finely pulverized product is processed by an apparatus that simultaneously performs the classification shown in FIG. 2 and the surface modification (spheronization) process using a mechanical impact force, whereby toner particles 1 having an average circularity of 0.950 are obtained. Obtained.

Toner particle 1: 100 parts by mass of hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 0.7 parts by mass and acicular titanium oxide fine particles (with hydrophobization treatment, BET = 57, primary number average particle diameter: 40 nm): 1.1 parts by mass were externally added with a Henschel mixer to obtain toner 1. Toner 1 had a weight average diameter D4 of 5.5 μm and an average circularity of 0.950.

(Toner Production Example 2)
3.5 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1.7 mol of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1.6 mol of terephthalic acid, 1.1 mol of trimellitic anhydride, 2.4 mol of fumaric acid, and 0.12 g of dibutyltin oxide were placed in a 4-liter four-necked flask made of glass. A thermometer, a stirring rod, a condenser, and a nitrogen introducing tube were attached to the four-necked flask and placed in a mantle heater. Under a nitrogen atmosphere, reaction was performed at 210 ° C. for 6 hours to obtain Resin 2.
-Resin 2: 100 parts by mass-Wax (normal paraffin, maximum endothermic peak temperature measured by differential scanning calorimeter (DSC): 75 ° C): 5.5 parts by mass-Polar polymer 1: 1.3 parts by mass Parts, 1,4-di-t-butylsalicylic acid aluminum compound: 0.7 parts by mass Cyan pigment (Pigment Blue 15: 3): 4.5 parts by mass Preliminarily mixed with a Henschel mixer in the above formulation, The material temperature was melt-kneaded at 130 ° C. with a shaft extrusion kneader. After cooling, it was coarsely pulverized to about 1 to 2 mm or less using a hammer mill, and then finely pulverized to a particle size of 15 μm or less with an air jet fine pulverizer. Further, the obtained finely pulverized product was subjected to surface modification of the obtained classified product by a hybridizer (manufactured by Nara Machinery Co., Ltd.) (rotation speed: 5000 rpm, treatment time: 3 minutes, treatment frequency: 1), and the average circularity 0.937 toner particles 2 were obtained.

Toner particle 2: 100 parts by mass, hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 0.7 parts by mass and acicular titanium oxide fine particles (having hydrophobic treatment, BET = 57 , Primary number average particle diameter: 40 nm) 1.1 parts by mass Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) was used to obtain toner 2. Toner 2 had a weight average particle diameter D4 of 6.2 μm and an average circularity of 0.937.

(Toner Production Example 3)
Styrene-n-butylacrylic copolymer resin (copolymerization mass ratio = 78: 22, weight average molecular weight = 380,000): 100 parts by mass Wax (normal paraffin, measured with a differential scanning calorimeter (DSC) Maximum endothermic peak temperature: 75 ° C.): 5.5 parts by mass, aluminum 1,4-di-t-butylsalicylate compound: 1.0 part by mass, cyan pigment (Pigment Blue 15: 3): 4.3 parts by mass Preliminarily mixed with a Henschel mixer with the above formulation, melt-kneaded at a material temperature of 130 ° C. with a twin-screw extruder kneader, after cooling, coarsely pulverized to about 1 to 2 mm using a hammer mill, then air It was finely pulverized to a particle size of 15 μm or less by a jet type fine pulverizer. Further, the obtained finely pulverized product was subjected to surface modification of the obtained classified product by a hybridizer (manufactured by Nara Machinery Co., Ltd.) (rotation speed: 5000 rpm, treatment time: 3 minutes, treatment frequency: 3 times), and the average circularity was 0.945 toner particles 3 were obtained.

Toner particle 3: 100 parts by mass, hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 0.5 parts by mass and acicular titanium oxide fine particles (having hydrophobic treatment, BET = 57 , Primary number average particle size: 40 nm) 1.3 parts by mass Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.) was used to obtain toner 3. Toner 3 had a weight average particle diameter D4 of 6.5 μm and an average circularity of 0.945.

(Toner Production Example 4)
After adding 450 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution to 400 parts by mass of ion-exchanged water and heating to 50 ° C., 10,000 rpm using a TK homomixer (manufactured by Koki Kogyo Co., Ltd.). Was stirred at. To this, 68 parts by mass of 1.0 M CaCl ₂ aqueous solution was added to obtain an aqueous medium containing calcium phosphate.

on the other hand,
-Styrene: 85 parts by mass-n-butyl acrylate: 15 parts by mass-C.I. I. Pigment Blue 15: 3: 4 parts by mass / polar polymer 1: 1.5 parts by mass / saturated polyester (acid value 10 mgKOH / g, peak molecular weight 11,000)
: 10 parts by mass / ester wax (maximum endothermic peak temperature measured with a differential scanning calorimeter (DSC): 67 ° C.)
: 9 mass parts The said prescription was heated at 60 degreeC, and it melt | dissolved and disperse | distributed uniformly at 5,000 rpm using TK type | system | group homomixer (made by a special machine chemical industry). In this, 3.5 mass parts of polymerization initiators 2,2′-azobis (2,4-dimethylvaleronitrile) were dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was charged into the aqueous medium and stirred at 11,000 rpm with a TK homomixer at 65 ° C. in an N ₂ atmosphere to granulate the polymerizable monomer composition. .

  Thereafter, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C. at a temperature rising rate of 40 ° C./hr after 6 hours, and the reaction was allowed to proceed for 6 hours. After completion of the polymerization reaction, the residual monomer was distilled off under reduced pressure. After cooling, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt. Thereafter, filtration, washing with ion exchange water, and drying were performed to obtain toner particles 4 having an average circularity of 0.983.

Toner particle 4: 100 parts by mass of hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 0.6 parts by mass and acicular titanium oxide fine particles (with hydrophobic treatment, BET = 57, primary number average particle size: 40 nm) 1.0 part by mass was externally added by a Henschel mixer to obtain toner 4 of the present invention. The toner 4 had a weight average diameter D4 of 5.9 μm and an average circularity of 0.983.

(Toner Production Example 5)
-Dispersion A-
Styrene: 350 parts by mass n-butyl acrylate: 95 parts by mass Acrylic acid: 30 parts by mass t-dodecyl mercaptan: 10 parts by mass Polar polymer 1: 0.5 part by mass The above composition is mixed and dissolved. And prepared as a monomer mixture.

Paraffin wax dispersion with a melting point of 78 ° C. (solid content concentration 30%, dispersed particle size 0.14 μm): 100 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC): 1.5 Part by mass / nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd .: Nonipol 400): 0.5 part by mass / ion-exchanged water: 1550 parts by mass The above composition is dispersed in a flask and heated while performing nitrogen substitution. Start. When the liquid temperature reached 70 ° C., a solution prepared by dissolving 6.56 parts by mass of potassium persulfate with 350 parts by mass of ion-exchanged water was added thereto. While maintaining the liquid temperature at 70 ° C., the monomer mixture was charged and stirred, and the liquid temperature was raised to 80 ° C. and emulsion polymerization was continued for 6 hours. After that, the liquid temperature was adjusted to 45 ° C. Got. Thus, the particle diameter in the obtained dispersion was 0.16 μm in average particle diameter, 60 ° C. in glass transition point of solid content, 16,000 in weight average molecular weight (Mw), and 11 in peak molecular weight. 000. Paraffin wax was contained in the polymer in an amount of 6% by mass. As a result of observing a thin piece of this solid content with a transmission electron microscope, it was confirmed that the polymer particles encapsulated the wax particles.

-Dispersion B-
Styrene: 350 parts by mass n-butyl acrylate: 95 parts by mass Acrylic acid: 30 parts by mass Polar polymer 1: 0.5 parts by mass The above ratios were mixed and dissolved to prepare a monomer mixture.

Fischer-Tropsch wax dispersion with a melting point of 105 ° C. (solid content concentration 30%, dispersion particle size 0.15 μm): 100 parts by mass Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC): 5 parts by mass / nonionic surfactant (manufactured by Sanyo Chemical Co., Ltd .: Nonipol 400): 0.5 parts by mass / ion-exchanged water: 1550 parts by mass Disperse the above composition in a flask and heat with nitrogen substitution To start. When the liquid temperature reached 70 ° C., a solution prepared by dissolving 5.80 parts by mass of potassium persulfate with 350 parts of ion-exchanged water was added thereto. While maintaining the liquid temperature at 70 ° C., the monomer mixture was charged and stirred, the liquid temperature was raised to 75 ° C. and emulsion polymerization was continued for 8 hours. The liquid temperature was adjusted to 40 ° C. and filtered through a filter. Got. Thus, the particle diameter in the obtained dispersion was 0.15 μm in average particle diameter, and the glass transition point of solid content was 64 ° C. The hydrocarbon wax was contained in the polymer in an amount of 6% by mass, and as a result of observing a thin piece of the solid content with a transmission electron microscope, it was confirmed that the wax particles were encapsulated.

-Dispersion C-
・ C. I. Pigment Blue 15: 3: 12 parts by mass, anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC): 2 parts by mass, ion-exchanged water: 78 parts by mass The above is mixed and a sand grinder mill is used. Dispersed to obtain a colorant dispersion C.

  300 parts by mass of dispersion A, 150 parts by mass of dispersion B and 30 parts by mass of dispersion C were charged into a 1-liter separable flask equipped with a stirrer, a cooling tube and a thermometer, and stirred. As a flocculant, 180 parts by mass of a 10% sodium chloride aqueous solution was dropped into this mixed solution, and the flask was heated to 54 ° C. while stirring the inside of the flask. After maintaining at 48 ° C. for 1 hour, it was confirmed by observation with an optical microscope that associated particles having a diameter of about 5 μm were formed.

  In the subsequent fusion process, after adding 3 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel flask was sealed and stirring was continued using a magnetic seal. While heating to 100 ° C., it was held for 3 hours. Then, after cooling, the reaction product was filtered, sufficiently washed with ion exchange water, and then dried to obtain toner particles 5 having an average circularity of 0.972.

Toner particle 5: 100 parts by mass of hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 0.7 parts by mass and acicular titanium oxide fine particles (with hydrophobization treatment, BET = 57, primary number average particle diameter: 40 nm) 0.9 part by mass was externally added by a Henschel mixer to obtain toner 5.

(Toner Production Example 6)
Bisphenol A ethylene oxide 2-mole adduct: 725 parts by mass, isophthalic acid: 275 parts by mass, and dibutyltin oxide: 2 parts by mass in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and normal pressure, 230 The reaction was carried out at 0 ° C. for 8 hours. Furthermore, after reacting at a reduced pressure of 10 to 15 mmHg for 6 hours, the mixture was cooled to 150 ° C., and 32 parts by mass of phthalic anhydride was added thereto and reacted for 2 hours. Next, the mixture was cooled to 80 ° C. and reacted with 190 parts by mass of isophorone diisocyanate in ethyl acetate for 2 hours to obtain a polyester prepolymer (A) having an isocyanate group. Next, 270 parts by mass of prepolymer (A) and 15 parts by mass of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester resin (i) having a weight average molecular weight of 65,000.

  In the same manner as above, bisphenol A ethylene oxide 2-mole adduct: 720 parts by mass and terephthalic acid: 280 parts by mass were subjected to polycondensation at 230 ° C. for 8 hours under normal pressure. Next, the reaction was performed at a reduced pressure of 10 to 15 mmHg for 5 hours to obtain an unmodified polyester (a) having a peak molecular weight of 5000.

  Urea-modified polyester-based resin (i): 200 parts by mass and unmodified polyester (a): 800 parts by mass are dissolved in and mixed with ethyl acetate / methyl ethyl ketone (MEK) (1/1) mixed solvent: 2000 parts by mass, An ethyl acetate / MEK solution of toner binder (I) was obtained. Part of the mixture was dried under reduced pressure to isolate toner binder (I)). Tg was 58 ° C.

  In a beaker, 240 parts by mass of the toner binder (I) ethyl acetate / MEK solution, pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 25 mpa · s): 20 parts by mass, C.I. I. Pigment Blue 15: 3 raw pigment: 6 parts by mass was added and stirred at 12,000 rpm with a TK homomixer at 60 ° C. to uniformly dissolve and disperse. Ion exchange water: 706 parts by mass, hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.): 294 parts by mass, sodium dodecylbenzenesulfonate: 0.2 parts by mass in a separate beaker Dissolved in. Next, the temperature was raised to 60 ° C., and the toner material solution was added and stirred for 15 minutes while stirring at 12000 rpm with a TK homomixer (manufacturer: Special Machine Industries). The mixture is then transferred to a Kolben equipped with a stirrer and a thermometer, and the temperature is raised to 98 ° C. to remove the solvent, followed by filtration, washing, drying, air classification, and toner particles having an average circularity of 0.960. 6 was obtained.

Toner particle 6: 100 parts by mass of hydrophobic silica fine particles (BET: 180 m ² / g, average primary particle size 30 nm): 1.0 part by mass and acicular titanium oxide fine particles (with hydrophobization treatment, BET = 57, primary number average particle diameter: 40 nm): 0.9 part by mass was externally added by a Henschel mixer to obtain toner 6. The toner 6 had a weight average diameter D4 of 6.0 μm and an average circularity of 0.960.

(Example 1)
To 92 parts by mass of the magnetic carrier 1, 8 parts by mass of the toner 1 was added and mixed with a tumbler mixer in a normal temperature and normal humidity (23 ° C., 50% RH) environment to obtain a developer 1.

  The developer 1 was subjected to image evaluations 1 to 5 using a cyan station of a full-color copying machine CLC5000 made by Canon. The development conditions were such that the development contrast was adjusted so that the image density was 1.40. The modified CLC5000 is as follows. The laser spot diameter was reduced so that it could be output at 600 dpi. The surface layer of the fixing roller of the fixing unit was changed to a PFA tube, and the oil application mechanism was removed.

  The image evaluation items and evaluation criteria are shown below. The evaluation results are shown in Table 2.

(Evaluation 1) Evaluation of carrier adhesion The development contrast was adjusted so that the toner toner development amount on the drum would be 0.3 mg / cm ² , and an A4 full surface solid halftone image under normal temperature and low humidity (23 ° C., 5% RH). The number of white spots in the carrier particle diameter when 5 sheets were continuously output was counted, and the average number per A4 sheet was judged.

<Evaluation criteria>
A: Very good (0)
B: Good (1 or more and 2 or less)
C: Normal (3 to 5)
D: Bad (more than 5)

(Evaluation 2) Evaluation of Image Density Stability Image density stability was evaluated by imaging 100,000 sheets using a horizontal band chart with an image area of 5% under normal temperature and low humidity (23 ° C., 5% RH). Went. The change in image density after the end of durability and after the endurance was used as a criterion for evaluation. For the image density, the solid portion (initial image density = 1.40) of the original image is averaged five times with a color reflection densitometer (X-RITE 404A: manufactured by X-Rite Co.), and the change value of the image density is measured. did. The evaluation was made based on the difference in concentration variation (Δ) between the initial durability and the durability.

<Evaluation criteria>
A: Very good (Δ = 0.08% or less)
B: Good (0.08 ≦ Δ <0.15%)
C: Normal (0.15 ≦ Δ <0.20%)
D: Poor (0.2% or more)

(Evaluation 3) Evaluation of fog The fog was evaluated by image output of 20,000 sheets using a horizontal band chart having an image area of 30% under low temperature and low humidity (23 ° C., 5% RH). The whiteness of the white background after durability is measured with a reflectometer (densitometer TC6MC: Tokyo Denshoku Technical Center), and the fog density (%) is calculated from the difference between the whiteness and the average whiteness of the transfer paper. ,evaluated. The evaluation criteria are as follows.

<Evaluation criteria>
A: Very good (less than 1.2%)
B: Good (1.2% or more and less than 2.4%)
C: Normal (2.4% or more and less than 3.6%)
D: Poor (3.6% or more)

(Evaluation 4) Evaluation of charging stability The charging stability was evaluated by imaging 20,000 sheets using a horizontal band chart with an image area of 30% under low temperature and low humidity (23 ° C., 5% RH). It was. Using the apparatus of FIG. 9, 1.0 g of the developer on the sleeve at the end of durability and at the end of durability in each environment was weighed, and the charge amount was measured. Judgment was made by the difference (Δ) in the charge amount between the initial durability and the end of durability.

<Evaluation criteria>
A: Very good (Δ = less than 3.0)
B: Good (3.0 ≦ Δ <5.0)
C: Normal (5.0 ≦ Δ <7.0)
D: Bad (Δ = 7.0 or more)

(Evaluation 5) Evaluation of storage stability The storage stability was measured on the drum after the completion of image output of 50,000 sheets using a horizontal band chart with an image area of 5% at high temperature and high humidity (30 ° C., 80% RH). Charge amount Q ₀ / M ₀ , and then measure the charge amount Q ₁ / M ₁ on the drum when the copier is turned off and left for a day. The storage stability is calculated from the following equation.
Standing stability Δ = | Q ₀ / M ₀ −Q ₁ / M ₁ |
A: Very good (Δ = less than 1.0)
B: Good (1.0 ≦ Δ <3.0)
C: Normal (3.0 ≦ Δ <7.0)
D: Bad (Δ = 7.0 or more)

(Examples 2 to 18 and Comparative Examples 1 to 7)
As shown in Table 2, the same evaluation was performed with the same configuration as in Example 1 except that the magnetic carrier and toner type of the developer were changed. The evaluation results are shown in Table 2.

  Next, evaluation was performed with a copying machine having an (auto-refresh) ACR mechanism.

(Example 19)
To 92 parts by mass of the magnetic carrier 4, 8 parts by mass of the toner 1 was added and mixed with a tumbler mixer to obtain a developer 4. On the other hand, 8 parts by mass of toner 1 was added to 1 part by mass of magnetic carrier 4 and mixed by a tumbler mixer to obtain a replenishment developer.

  The developer 4 and the replenishment developer 1 thus obtained were adjusted using a commercially available iRC3100 (Canon) black station, adjusted in development contrast so that the initial image density was 1.40 in each environment, and in a monochromatic mode. Drawing evaluations 6 to 10 were performed. By the way, this body is not equipped with a drum heater.

  The image evaluation items and evaluation criteria are shown below. The evaluation results are shown in Table 3.

(Evaluation 6) Evaluation of Image Density Stability Image density stability was evaluated by imaging 100,000 sheets using a horizontal band chart with an image area of 5% under normal temperature and low humidity (23 ° C., 5% RH). Went. The change in image density after the end of durability and after the endurance was used as a criterion for evaluation. For the image density, the solid portion (initial image density = 1.40) of the original image is averaged five times with a color reflection densitometer (X-RITE 404A: manufactured by X-Rite Co.), and the change value of the image density is measured. did. The evaluation was made based on the difference in concentration variation (Δ) between the initial durability and the durability.

<Evaluation criteria>
A: Very good (Δ = 0.08% or less)
B: Good (0.08 ≦ Δ <0.15%)
C: Normal (0.15 ≦ Δ <0.20%)
D: Poor (0.2% or more)

(Evaluation 7) Evaluation of fog The fog was evaluated by image output of 20,000 sheets using a horizontal band chart having an image area of 30% under normal temperature and low humidity (23 ° C., 5% RH). The whiteness of the white background after durability is measured with a reflectometer (densitometer TC6MC: Tokyo Denshoku Technical Center), and the fog density (%) is calculated from the difference between the whiteness and the average whiteness of the transfer paper. ,evaluated. The evaluation criteria are as follows.

<Evaluation criteria>
A: Very good (less than 1.2%)
B: Good (1.2% or more and less than 2.4%)
C: Normal (2.4% or more and less than 3.6%)
D: Poor (3.6% or more)

(Evaluation 8) Evaluation of charging stability The charging stability was evaluated by imaging 20,000 sheets using a horizontal band chart with an image area of 30% under normal temperature and low humidity (23 ° C., 5% RH). It was. Using the apparatus of FIG. 9, 1.0 g of the developer on the sleeve at the end of durability and at the end of durability in each environment was weighed, and the charge amount was measured. Judgment was made by the difference (Δ) in the charge amount between the initial durability and the end of durability.

<Evaluation criteria>
A: Very good (Δ = less than 3.0)
B: Good (3.0 ≦ Δ <5.0)
C: Normal (5.0 ≦ Δ <7.0)
D: Bad (Δ = 7.0 or more)

(Evaluation 9) Carrier recoverability from developer container Carrier recoverability from developer container is 1000 sheets using a horizontal band chart with an image area of 5% under low temperature and low humidity (15 ° C., 5% RH). After dispensing, the difference from the 50% average particle diameter of the carrier in the collection container after the endurance of 100,000 sheets is calculated based on the 50% average particle diameter of the carrier in the carrier collection container.
A: ± 2.0% or less B: ± 5.0% or less C: ± 7.0% or less D: Over ± 7.0%

(Evaluation 10) Toner discharging property from replenishment developer container A replenishment developer container is filled with a replenishment developer in an amount of 0.43 g / cc with respect to the inner volume of the container, and the container is driven at a speed of 17 rpm Rotate and check visually for discharge.
A: Total discharge.
B: Almost all discharged. There is some residual developer in the dead space.
C: Residual developer present on inner wall.
D: The opening is blocked and blocking occurs.

(Examples 20 to 23, Comparative Example 8)
As shown in Table 3, the evaluation was performed in the same manner as in Example 19 except that the toner amounts in the developer and the replenisher were changed. The evaluation results are shown in Table 3.

It is an example of a sectional view of a magnetic carrier in which a resin is added to a porous core. It is the schematic of a surface modification processing apparatus. 1 is a configuration diagram of an image forming apparatus including a rotary rotation type developing device and an intermediate transfer member. It is an example of a sectional view of a developing device in a rotary rotation system. FIG. 2 is an enlarged configuration diagram of a rotary rotation type developing device. 1 is a configuration diagram of a tandem image forming apparatus. It is an example of a cross-sectional view of a developing device used in a tandem system. The figure of the tablet molding machine used when measuring the volume specific resistance of particle | grains is shown. The figure of the apparatus used in order to measure the triboelectric charge quantity in an Example is shown.

Claims (12)

A two-component developer having a toner and a magnetic carrier,
The toner has toner particles containing at least a binder resin, a colorant, a release agent, and a polymer or copolymer having a sulfonic acid group, a sulfonic acid group, or a sulfonic acid ester group, and at least inorganic fine particles. Toner,
The magnetic carrier is
i) composite particles containing a resin in the pores of the porous magnetic core particles;
ii) The true specific gravity is 2.5 or more and 4.2 g / cm ³ or less,
iii) The volume-based 50% particle size (D50) is 15 or more and 70 μm or less,
iv) A two-component developer having an average circularity of 0.850 or more and 0.950 or less and an average circularity variation coefficient of 1.0 or more and 10.0% or less.   The two-component developer according to claim 1, wherein the composite particles are coated with a resin coat layer.   The two-component developer according to claim 1, wherein the resin component contains a silicone-based resin.   The two-component developer according to any one of claims 1 to 3, wherein the resin coat layer contains a silicone resin.   The two-component developer according to any one of claims 1 to 4, wherein the magnetic carrier contains the resin component and fine particles having a number average particle diameter of 10 to 500 nm.   The circularity measured by the flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is divided into 800 to a circularity range of 0.2 to 1.0. The two-component developer according to claim 1, wherein the analyzed toner has an average circularity of 0.940 or more and 1.000 or less. Used in a two-component development method in which a developer for replenishment containing at least toner and a magnetic carrier is developed while being replenished to the developing unit, and at least the excess magnetic carrier in the developing unit is discharged from the developing unit as necessary. A developer for replenishment,
The replenishment developer contains 2 to 50 parts by mass of the toner with respect to 1 part by mass of the magnetic carrier.
The toner includes at least a binder resin, a colorant, a release agent, and toner particles containing a polymer having a functional group selected from the group consisting of a sulfonic acid group, a sulfonic acid group, and a sulfonic acid ester group; A toner having inorganic fine particles;
The magnetic carrier is
i) composite particles having porous magnetic core particles and a resin component;
ii) The true specific gravity is 2.5 or more and 4.2 g / cm ³ or less,
iii) The volume-based 50% particle size (D50) is 15 or more and 70 μm or less,
iv) A developer for replenishment having an average circularity of 0.850 or more and 0.950 or less and an average circularity variation coefficient of 1.0 or more and 10.0% or less.   The replenishment developer according to claim 7, wherein the composite particles are coated with a resin coat layer.   The replenishment developer according to claim 7 or 8, wherein the resin component contains a silicone resin.   The replenishment developer according to claim 7, wherein the resin coat layer contains a silicone-based resin.   The replenishment developer according to any one of claims 7 to 10, wherein the magnetic carrier contains the resin component and fine particles having a number average particle diameter of 10 to 500 nm.   The circularity measured by the flow type particle image measuring apparatus having an image processing resolution of 512 × 512 pixels (0.37 μm × 0.37 μm per pixel) is divided into 800 to a circularity range of 0.2 to 1.0. The replenishment developer according to claim 7, wherein the analyzed toner has an average circularity of 0.940 to 1.000.

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