JP2003295524A - Developer for replenishment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer for replenishment with which a stable image can be obtained through the life of a main body. <P>SOLUTION: As to the developer for replenishment, toner has weight average particle diameters ranging 3 to 6 μm, toner particles of 2.52 μm or smaller than this are 1.5 to 20% by number, the accumulated value of the weight average particle diameter of 1.5 or larger than this ranges 0.5 to 10%, a carrier has specific resistance R<SB>1000</SB>in the case of applying electric field intensity 1000 (V/cm) satisfying 1×10<SP>10</SP>≤R<SB>1000</SB>≤1×10<SP>15</SP>, and the carrier and the toner are contained by the blending rate of toner 2 to 50 part with respect to 1 part of the carrier. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a replenishing developer for use in a developing method for developing while replenishing a replenishing developer.

[0002]

2. Description of the Related Art U.S. Pat. No. 2,29 as an electrophotographic method
Various methods are described in Japanese Patent No. 7,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748. In these methods, an electrostatic latent image is formed by irradiating a photoconductive layer of a latent image carrier with a light image corresponding to a document, and then toner is attached onto the electrostatic latent image to form the electrostatic latent image. The image is developed and, if necessary, the toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, heat and pressure, solvent vapor or the like to obtain a copy or print.

In recent years, with the development of computers, multimedia, etc., there has been a demand for means for outputting further high-definition full-color images in a wide range of fields from offices to homes, and image quality is not deteriorated even by copying or printing a large number of sheets. In order to achieve high durability, various studies have been conducted from each viewpoint.

The step of developing an electrostatic latent image in the electrophotographic method is to form an image on the electrostatic latent image using charged toner particles by utilizing the electrostatic interaction of the electrostatic latent image. Of the developers for developing electrostatic latent images with toner,
There are a one-component developer that uses a magnetic toner in which a magnetic material is dispersed in a resin, and a two-component developer that mixes a non-magnetic toner with a magnetic carrier. The latter is preferably used for the printer.

In the two-component developing method, the toner is replaced by the development, but the carrier is not consumed but stays in the developing device. Therefore, carrier contamination occurs due to transfer of the toner component to the carrier, and the carrier itself causes stress in the developing device. When the resin coating layer is peeled off, the developer characteristics are affected, and the image density may fluctuate or fogging may occur.

As a solution to this problem, for example, in Japanese Patent Publication No. 2-21591, a carrier is added together with the toner consumed by the development, and the carrier in the developing device is replaced little by little to change the charge amount. A so-called trickle developing device is disclosed which suppresses the above-mentioned phenomenon and stabilizes the image density. However, since the carrier used is an iron powder carrier with a large saturation magnetization,
Since the stress on the carrier in the developing device is large and the carrier is easily deteriorated during the repeated copying operation, the image deterioration is likely to be accelerated unless the amount of the replenishing carrier is increased, which is not satisfactory.

On the other hand, in Japanese Patent Laid-Open No. 3-145678, a carrier having a resistance value higher than that of a carrier previously stored in a developing device is made to contain toner to maintain chargeability and suppress deterioration of image quality. Is disclosed. Further, Japanese Patent Application Laid-Open No. 11-223960 discloses that a carrier that imparts a higher charge amount to a toner contains a toner to maintain chargeability and suppress deterioration of image quality.

However, in these methods, since the amount of carrier to be replaced is different due to the difference in toner consumption, the resistance or charge amount of the developer in the developing device changes, and the fluctuation of the image density easily occurs, which is satisfactory. Was not.

Further, Japanese Unexamined Patent Publication No. 8-234550 discloses a method of sequentially replenishing each toner by using a plurality of replenishment toners containing a carrier having different physical properties from the carrier previously stored in the developing device. ing. However, in practice, it is extremely difficult to replenish the replenishment toner containing a plurality of carriers having different physical properties in one toner replenishment container into the developing device so that they do not mix with each other. Since they are different from each other, it is very difficult, and since the amount of toner is large relative to the carrier, deterioration of the carrier is likely to occur and a stable image cannot be obtained for a long period of time.

Further, Japanese Patent Laid-Open No. 2001-330985 discloses a replenishing developer in which the true specific gravity of a carrier is reduced to suppress collision energy between toner particles and carrier particles, maintain chargeability, and suppress deterioration of image quality. Is disclosed. However, it is still not sufficient to eliminate the difference in specific gravity between the toner and the carrier, and the toner and the carrier are separated in the replenishing container due to stirring or the like, which makes it impossible to stably replenish the developer. Have a point.

[0011]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving various problems as described above. That is, an object of the present invention is to provide a replenishment developer capable of obtaining a stable image throughout the life of the main body.

[0012]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a replenishment developer for use in a developing method in which development is performed while replenishing a replenishment developer has the following constitution: It was found that a good image can be obtained for a long time.

That is, in the replenishing developer of the present invention, the toner has a weight average particle diameter of 3 to 6 μm and is 2.52
1.5 to 20% by number of toner particles having a size of μm or less, and a cumulative value of 1.5 times the weight average particle size or more is 0.5 to
10% or less, and the carrier has an electric field strength of 1000 (V
/ Cm) specific resistance R ₁₀₀₀ when applied is 1 × 10 ¹⁰ ≦ R ₁₀₀₀ ≦
It is 1 × 10 ¹⁵ , and it is characterized in that the carrier and the toner are contained in the amount of 2 parts by mass of the toner in 1 part by mass of the carrier.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

<1> Carrier in the present invention The carrier is the ratio when an electric field strength of 1000 (V / cm) is applied.
Resistance R₁₀₀₀Is 1 × 10 ^Ten≤ R₁₀₀₀≦ 1 × 10¹⁵The filling
ing. 1 x 10^TenIf less than,
The charge generated during the frictional contact of the
It becomes easier for the nurse and the carrier to leave. Present in that state
Difference in specific gravity between toner and carrier when replenishing the imager
Due to uneven distribution, such as the carrier collecting below the supply container
Occurs and the replenishment of the developer becomes unstable. Also,
1 x 10¹⁵If it is higher than the charge of the toner and carrier
Leakage is small and the carrier can easily hold the toner.
Therefore, although the developer is less likely to be biased,
When the image is supplied to the imager to form an image, the edge enhancement
An image is easily formed, and the charge on the carrier surface
Is less likely to leak due to the charge-up phenomenon
Image density drop, newly replenished carrier and toner
Fogging and scattering due to uneven charging with
It may cause other harmful effects. Furthermore, supply capacity
It will be charged with substances such as the inner wall of the developing unit and the developing unit.
The amount of charge of the toner that should be removed may become uneven.
is there. In addition, there is no deterioration of the carrier due to the adhesion of external additives.
However, image defects are likely to occur.

As a method for obtaining a carrier satisfying 1 × 10 ¹⁰ ≦ R ₁₀₀₀ ≦ 1 × 10 ¹⁵ , I. II. Regular coating of ferrite particles uniformly and completely with a coating resin II. Obtain ferrite particles with large surface irregularities, and contain (impregnate) a large amount of resin therein. III. A method of obtaining a magnetic substance-dispersed carrier in which a magnetic substance is dispersed in a binder resin can be mentioned. Among them, III is the most preferable because it can control even the resistance of the core material to a desired value and it is easy to uniformly control the magnetic characteristics of the carrier surface. Further, by using the magnetic substance-dispersed resin carrier in which the metal compound particles are dispersed in the binder resin, the specific gravity can be reduced as compared with the conventional carrier. As a result, since the difference in specific gravity from the toner can be reduced, the replenishment developer can be stably replenished without uneven distribution of the replenishment developer.

In particular, the magnetic material-dispersed resin carrier produced by the polymerization method has excellent fluidity because the carrier has little shape distortion and it is relatively easy to form a spherical shape having high particle strength. In addition, since the particle size can be controlled sharply, it is difficult to make a difference in the particle size distribution between the carrier remaining in the developing device and the recovered carrier, and there is no uneven distribution such as only fine powder or coarse powder being recovered. It is also preferable because it has excellent properties.

Further, the carrier has an electric field strength of 1000.
The specific resistance at the time of applying (V / cm) is R ₁₀₀₀ , 3000
Assuming that the specific resistance under application of (V / cm) is R ₃₀₀₀ , 1.0 ≦ log (R ₁₀₀₀ ) / log (R ₃₀₀₀ ) ≦
It is preferably 1.3.

It is practically impossible that the log (R ₁₀₀₀ ) / log (R ₃₀₀₀ ) is less than 1.0. Also,
When it exceeds 1.3, the resistance on the surface of the carrier is high to some extent, but the resistance inside the carrier particles is considered to be low. In the case of such a two-layer structure, when the surface layer is peeled off due to a mechanical shock or the like and the inside having a low resistance is exposed, the above-mentioned uneven distribution of the developer may occur in the replenishing container. Further, when the toner is actually supplied to the developing device to form an image, carrier adhesion to the photoconductor is likely to occur, and the photoconductor is liable to be scratched or directly transferred onto paper to cause image defects. Further, the developing bias may leak through the carrier and disturb the electrostatic latent image drawn on the photoconductor.

1.0 ≦ log (R ₁₀₀₀ ) / log (R
₃₀₀₀ ) ≦ 3.0, a method for obtaining a carrier is as follows. By reducing the specific surface area of the magnetic powder, the electric conduction path for electric charges is reduced, and the resistance value of the magnetic powder is increased by surface treatment such as lipophilic treatment. II. As metal compound particles, it has higher resistance than magnetic powder,
It is used together with the non-magnetic metal oxide particles and the abundance of the non-magnetic metal oxide particles on the surface of the carrier particles is increased. There is a method. Further, in order to achieve II, as a physical means, a) a particle size difference between the particle size ra of the magnetic oxide particles and the particle size rb of the non-magnetic oxide particles is provided. Examples of the particularly effective chemical means in the polymerization method, which are preferably used for obtaining a magnetic substance-dispersed resin carrier, include b) lipophilic treatment of non-magnetic metal oxide particles rather than magnetic oxide particles. Increase the amount. c) The lipophilic treatment agent for non-magnetic metal oxide particles is treated with a treatment agent having a larger number of functional groups than magnetic oxide particles. d) In the metal oxide particles after the lipophilic treatment, the nonmagnetic metal oxide particles have a functional group having a higher polarity than the magnetic oxide particles. There is a method. Here, the lipophilic treatment is selected from the group consisting of an epoxy group, an amino group, and a mercapto group on the surface of the metal oxide particles in order to maintain proper mixing properties of the metal oxide particles and the binder resin. 1
It is a means of treating with a treating agent having one or more functional groups.

The carrier resistance was measured using a powder insulation resistance measuring instrument manufactured by Vacuum Riko Co., Ltd. The conditions at that time were such that a carrier left at 23 ° C. and 60% for 24 hours or more was put in a measuring cell of Φ20 mm (0.283 (cm ² )) and sandwiched by a load electrode of 120 g / cm ² (11.8 kPa). , Thickness 1mm, applied voltage 100V
To 100V every 100V. R ₁₀₀₀ , R
₃₀₀₀ was obtained from the resistance curve at that time.

The content of the metal compound in the carrier particles of the present invention is preferably 80 to 95% by mass. When the content of the metal compound is less than 80% by mass, an appropriate specific gravity cannot be obtained, so that the mixing property with the toner deteriorates and it becomes difficult to obtain uniform charging. Further, although related to the magnetic characteristics of the carrier, the carrier is likely to adhere to the photoconductor. Further, when the content exceeds 95% by mass, the difference in specific gravity between the toner and the carrier is widened, so that even if the resistance value is controlled to the value of the present invention, the developer is likely to be biased in the replenishing container. Further, in the case of a magnetic material dispersion type carrier which is particularly preferably used as a form of the present invention, the carrier strength is lowered and problems such as carrier cracking due to durability are likely to occur.

The content of the metal compound was obtained by measuring the mass (W1) of the initial carrier and the mass (W2) of the residue remaining after the treatment with a strong acid having a pH of 1 or less for 24 hours or more, and using the following formula. [(W1-W2) / W1] x 100

The magnetic characteristics of the carrier are 1000 / 4π.
The strength of magnetization σ ₁₀₀₀ at (kA / m) is 35 to 75 Am ²
/ Kg is good, preferably 45-75 Am ²
/ Kg, more preferably 50 to 75 Am ² / kg. Furthermore, the residual magnetization σr is 0.1 to 20.
It is preferably Am ² / kg.

When σ ₁₀₀₀ exceeds 75 Am ² / kg, stress in the replenishment developer container and in the developing device increases and carrier deterioration is accelerated, though it depends on the carrier particle size. Unless the amount of the carrier is increased, durability deterioration of the developer is likely to occur due to copying or printing a large number of sheets. Also, when the image is actually formed by being replenished to the developing device, the density of the magnetic brush formed on the developer bearing member at the developing pole is reduced, which is related to the particle size of the carrier. Becomes longer and becomes stiffer, so uneven sweeping is likely to occur on the copy image, and durability deterioration of the developer is particularly likely to occur due to copying or printing a large number of sheets. Further, the carrier is less likely to be peeled off from the developer carrying member in the developing device, and the carrier is selectively deteriorated.

If it is less than 35 Am ² / kg, the magnetic force of the carrier is lowered even if the carrier fine powder is cut when the image is actually formed by replenishing it to the developing device, carrier adhesion is likely to occur, and the toner transportability is deteriorated. Tends to decline.

When σr is smaller than 0.1 Am ² / kg, the fluidity is so good that the toner and the carrier are densely clogged, especially when the spherical toner and the spherical carrier produced by the polymerization method are used. It is easy to cause deterioration of the replenishment developer and defective replenishment. On the contrary, 20 Am ²
If it is larger than / kg, the toner is not mixed well with the carrier due to the chaining of the carrier, leading to poor charging and eventually poor replenishment.

The magnetic characteristics are measured using an oscillating magnetic field type automatic recording apparatus for magnetic characteristics BHV-35 manufactured by Riken Denshi Co., Ltd. The magnetic characteristic value of the carrier is 1000 / 4π (kA /
The external magnetic field of m) is created and the strength of the magnetization at that time is calculated. The carrier is prepared in a state that it is packed in a cylindrical plastic container so that the carrier does not move tightly, the magnetization moment is measured in this state, and the actual weight when the sample is put is measured, Magnetization strength (Am
² / kg).

The carrier particle size is preferably 50 to 60 μm, more preferably 30 to 50 μm in terms of volume-based 50% average particle size.

If the carrier particle size is less than 25 μm, the carrier adhesion to the non-image area due to the particles on the fine particle side in the carrier particle size distribution may not be satisfactorily prevented. Also, it becomes difficult to obtain sufficient resistance. If it is larger than 60 μm, the fineness of the magnetic brush is likely to be impaired, and image unevenness may occur.

As the particle size distribution of the carrier of the present invention, the content of carrier particles of 20 μm or less by the mesh method is 0.01 to 10% by mass, and the content of 74 μm or more is 0.1 to 20% by mass. Is desirable. If the amount of particles having a particle size of 20 μm or less is less than 0.01% by mass, the developer is likely to be densely clogged, and agent deterioration is likely to occur. 1
If it is more than 0% by mass, carrier adhesion due to fine particles of the carrier tends to occur. Particles with a size of 74 μm or more are 0.
Even when the content is less than 1% by mass, agent deterioration due to high density is likely to occur. If the content is more than 20% by mass, the carrier with a large particle size is likely to be recovered, but the particle size distribution of the carrier in the replenishment developer and the carrier in the developing device is likely to change, depending on the recovery method. , Which affects the charging property. In addition, the surface area required to give an appropriate amount of charge to the toner cannot be obtained.

Further, the magnetic properties σ _{1000 at} 1000 / 4π of carrier particles of 20 μm or less by the mesh method.
Is preferably ^{20 to} 75 (Am ² / kg). When the magnetic property is less than 20 Am ² / kg, carrier adhesion is likely to occur. Also, 75 Am ² / kg
When it exceeds the above range, the carrier is less likely to be peeled off from the developing sleeve in the developing device, and the carrier is selectively deteriorated.

The average particle diameter was measured by a laser diffraction type particle size distribution meter (manufactured by Horiba Ltd.).

For the measurement of the amount of fine powder of 20 μm or less and the amount of coarse powder of 74 μm or more by the mesh method, a mesh with each opening is prepared and an electromagnetic experimental sieve shaker (Fritche Japan Anatolyset 3 type) is used. To measure. The conditions are: Timer = 5 min, Amplitide intensity =
2 and 1 kg of the sample was used.

The true specific gravity of the carrier is preferably 2.5 to 4.5, more preferably 3.0 to 4.5. True specific gravity is 2.5
If it is less than the above, carrier adhesion is likely to occur although it is related to the magnetic properties of the carrier. Further, the mixing property with the toner deteriorates, and it becomes difficult to obtain uniform charging. If the true specific gravity exceeds 4.5, the share in the developer becomes large, and the spent by the toner or the peeling of the coat resin is likely to occur.

Further, since the surface area per mass can be increased by the smaller specific gravity, the toner and the carrier are not separated even if the toner concentration is increased. As a result, not only is there an effect on the stable supply of the replenishment developer, but the mass of the developing device and the replenishment developer container can be reduced and the size can be reduced.

The binder resin of the magnetic substance-dispersed resin carrier preferably used in the carrier of the present invention is preferably a thermosetting resin, and a resin partially or wholly three-dimensionally crosslinked, such as a phenol resin. It is preferable that it is a thermosetting resin containing. By using this resin, the dispersed metal compound particles can be firmly bound, so that the strength of the magnetic substance-dispersed carrier can be increased and the metal compound particles are not detached even when copying a large number of sheets.

The carrier of the present invention is preferably used by being coated with a coating resin such as a silicone resin from the viewpoint of improving the charge imparting property and the spent resistance, and a thermosetting resin is used as the binder resin. By doing so, the adhesiveness and the uniformity are excellent, and it is possible to coat more favorably.

The method for obtaining the magnetic substance-dispersed carrier is not particularly limited, but in the present invention, the monomer to be the binder resin, the metal compound particles and the solvent are uniformly dispersed or dissolved. In such a solution, a method for producing a polymerization method in which particles are produced by polymerizing a monomer, in particular, a metal oxide dispersed in carrier particles is subjected to a lipophilic treatment to have a sharp particle size distribution, A method of obtaining a magnetic substance-dispersed resin carrier free of fine powder is preferably used.

The toner of the present invention has a weight average particle diameter of 3
When a toner having a small particle diameter of ˜6 μm is used, it is preferable that the carrier particle diameter also be reduced in accordance with the toner. Even if the carrier particle diameter is reduced by the above-described manufacturing method, the average particle diameter is small. Carriers with less fine powder can be manufactured regardless of the diameter.

As the monomer used for the binder resin of the carrier core, a radical polymerizable monomer can be used. For example, styrene; o-methylstyrene, m
-Styrene derivatives such as methylstyrene, p-methoxystyrene, p-ethylstyrene, p-tert-butylstyrene; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, acrylic acid Acrylic esters such as isobutyl, octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, n-methacrylic acid Propyl, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylamido methacrylate. Methacrylic acid esters such as methyl, diethylaminoethyl methacrylate and benzyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl ether, Isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether p
Examples thereof include vinyl ethers such as -methyl phenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether and p-methoxyphenyl vinyl ether; and diene compounds such as butadiene.

These monomers can be used alone or as a mixture, and a suitable polymer composition can be selected so as to obtain desired properties.

The binder resin of the carrier core is preferably three-dimensionally crosslinked. As the cross-linking agent, it is preferable to use a cross-linking agent having two or more polymerizable double bonds per molecule. As the cross-linking agent, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate,
3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate,
1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol tetramethacrylate, glycerol acryloxydimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone Is mentioned. Two or more kinds may be appropriately mixed and used.

The cross-linking agent can be mixed in advance with the polymerizable mixture, or can be appropriately added during the polymerization, if necessary.

Other monomers for the binder resin of the carrier core include bisphenols and epichlorohydrin which are starting materials for epoxy resin; phenols and aldehydes which are starting materials for phenol resin; urea and aldehyde which are starting materials for urea resin. Kinds; melamine and aldehydes, which are starting materials for melamine resin, can be mentioned.

The most preferred binder resin is a phenolic resin. As its starting material, phenol, m-
Examples thereof include phenol compounds such as cresol, 3,5-xylenol, p-alkylphenol, resorcil, and p-tert-butylphenol, and aldehyde compounds such as formalin, paraformaldehyde, and furfural. A combination of phenol and formalin is particularly preferable.

When a phenol resin or melamine resin is used, a basic catalyst can be used as a curing catalyst. As the basic catalyst, various kinds of catalysts that are commonly used in the production of resol resins can be used. Specific examples include amines such as aqueous ammonia, hexamethylenetetramine, diethyltriamine, and polyethyleneimine. In the present invention, it is preferable to use ammonia water.

The metal compound particles used for the magnetic substance-dispersed resin carrier include MO.Fe ₂ O ₃ or M exhibiting magnetism.
Examples thereof include magnetite or ferrite represented by the formula of Fe ₂ O ₄ . In the formula, M represents a trivalent, divalent or monovalent metal ion. As M, Mg, Al, Si, Ca,
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, C
u, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn,
Examples include Ba, Pb, and Li.

M can be used alone or in combination. For example, magnetite, Zn-Fe ferrite, M
n-Zn-Fe system ferrite, Ni-Zn-Fe ferrite, Mn-Mg-Fe system ferrite, Ca-Mn-F
e type ferrite, Ca-Mg-Fe type ferrite, Li
Examples of the iron-based oxides include -Fe-based ferrite and Cu-Zn-Fe-based ferrite.

The above-mentioned magnetic metal compound particles and the following non-magnetic metal compound particles may be mixed and used. For example, non-magnetic metal compound particles include Al ₂ O ₃ and Si.
O ₂ , CaO, TiO ₂ , V ₂ O ₅ , CrO, MnO ₂ , α
_{-Fe 2 O 3, CoO, NiO} , CuO, ZnO, Sr
_{O, Y 2 O 3, ZrO} 2 and the like. Thus, when at least two or more kinds of metal compound particles are mixed and used, it is preferable to use metal compound particles having a similar specific gravity and shape so as to enhance the adhesion with the binder resin and the strength of the carrier. Therefore, it is more preferable. For example, magnetite and hematite, magnetite and γ-Fe ₂ O ₃ , magnetite and S
iO ₂ , magnetite and Al ₂ O ₃ , magnetite and Ti
A combination of O ₂ can be preferably used. Among them, a combination of magnetite and hematite can be particularly preferably used.

When the above-mentioned metal compound particles are used, the number average particle size of the metal compound particles exhibiting magnetism is preferably 0.02 to 2 μm, though it varies depending on the particle size of the carrier. When two or more kinds of metal compound particles are used, the number average particle diameter of the metal compound exhibiting magnetism is preferably 0.02 to 2 μm, and the number average particle diameter of the other nonmagnetic metal compound particles is 0.05 to It is preferably 5 μm.

In this case, the particle size ratio rb / the number average particle size (average particle size ra) of the metal compound particles exhibiting magnetism and the number average particle size (average particle size rb) of the other non-magnetic metal compound particles.
Ra is preferably more than 1 and 5 or less, and more preferably 1.2 or more and 5.0 or less. When it is 1.0 times or less, the metal compound particles having low specific resistance and exhibiting ferromagnetism are likely to appear on the surface, it is difficult to increase the specific resistance of the carrier, and it becomes difficult to obtain the effect of preventing carrier adhesion. On the other hand, if it exceeds 5 times, the strength of the carrier is apt to be lowered and the carrier is apt to be destroyed.

The number average particle diameter of the metal oxide particles is measured as follows. Using a photographic image magnified 5000 to 20000 times with a transmission electron microscope H-800 manufactured by Hitachi, Ltd., 300 or more particles having a particle size of 0.01 μm or more are randomly extracted, and Nireco Co., Ltd. The particle size of the metal oxide particles is measured with a horizontal Feret diameter by an image processing analyzer Luzex3 manufactured by KK and averaged to calculate a number average particle diameter.

Ratio of metal compound particles dispersed in binder resin
The resistance is 1 × 10 for the metal compound particles exhibiting magnetism.³Ω ・ c
Those having a range of m or more are preferable, and in particular, metallization of two or more kinds.
When mixed with compound particles, it is a metallization that exhibits magnetism.
Resistivity of compound particles is 1 × 10 ³Ω ・ cm or more is preferable
The other non-magnetic metal compound particle exhibits magnetism.
Use one with higher specific resistance than metal compound particles
It is preferable. Preferably, the non-magnetic material used in the present invention
The specific resistance of the metal compound particles is 1 × 10⁸Ω · cm or more
More preferably 1 × 10^TenΩ · cm or more is preferable.

The specific resistance of the metal compound particles exhibiting magnetism is 1 ×
If it is less than 10 ³ Ω · cm, it is difficult to obtain a desired high specific resistance even if the content is reduced, and charge injection is likely to occur, image quality is deteriorated, and carrier adhesion is likely to occur.

When two or more kinds of metal compound particles are used, the specific resistance of the non-magnetic metal compound particles is 1 × 1.
0 ⁸ Omega · less than cm and the specific resistance of the magnetic material dispersed resin carrier is lowered, not preferable because the effect of the present invention becomes difficult to obtain.

The method for measuring the specific resistance of the metal compound particles conforms to the method for measuring the specific resistance of the carrier.

In the magnetic substance-dispersed resin carrier in which two or more kinds of metal compound particles are dispersed, the content of the metal compound particles showing magnetism in the whole metal compound particles contained is 5.
It is 0 to 95 mass%. If the amount is less than 50% by mass, the magnetic substance-dispersed resin carrier can have a high resistance, but the magnetic force as a carrier becomes small, which may cause carrier adhesion. Further, if it exceeds 95% by mass, depending on the specific resistance of the metal compound particles exhibiting magnetism, it may not be possible to increase the resistance of the more preferable magnetic material-dispersed resin carrier.

The metal compound particles contained in the magnetic substance-dispersed resin carrier in the present invention are subjected to lipophilic treatment so that the particle size distribution of the magnetic substance-dispersed resin carrier is sharpened, and the carrier of the metal compound particles is used. It is preferable for preventing the desorption from the. In particular, when a carrier is produced by a polymerization method which is preferably used, the polymerization reaction proceeds from a liquid in which the monomer and the solvent are uniform, and at the same time, particles insolubilized in the solution are produced. At that time, it is considered that the metal oxide has a function of being uniformly and densely incorporated inside the particles and a function of preventing the particles from aggregating and sharpening the particle size distribution. Furthermore, when a metal compound subjected to lipophilic treatment is used, it is not necessary to use a suspension stabilizer such as calcium fluoride, and the suspension stabilizer remains on the surface of the carrier to inhibit chargeability and to prevent carrier Non-uniformity of coating resin when coating, such as silicone resin,
It is possible to prevent reaction inhibition when coated with a reactive resin.

The lipophilic treatment of the metal compound particles is performed by an organic compound having one or more functional groups selected from an epoxy group, an amino group and a mercapto group, or a mixture thereof. It is preferable to use an agent. In particular, when the carrier is produced by a polymerization method which is preferably used, the charge imparting performance is stable by treating with a treating agent having a group having the above lipophilicity and a balance between hydrophobicity and hydrophilicity. However, a highly durable carrier with high particle strength can be obtained. Of these, an epoxy group is particularly preferably used.

The metal compound particles were added in an amount of 0.
It is preferably treated with 1 to 10 parts by mass (more preferably 0.2 to 6 parts by mass) of the lipophilic treatment agent in order to enhance the lipophilicity and hydrophobicity of the metal compound particles.

In particular, when two or more kinds of metal compound particles are mixed and used, it is preferable to treat the non-magnetic metal compound particles in a larger amount than the magnetic metal compound particles. By doing so, in particular, when produced by a polymerization method, many nonmagnetic metal compound particles having high resistance can be present on the particle surface, and the resistance of the carrier particles can be appropriately maintained.

Further, it is preferable that the non-magnetic metal compound particles are treated with a treating agent having a larger number of functional groups than the magnetic metal compound particles from the viewpoint of maintaining resistance. In particular, it is preferable that the non-magnetic metal compound particles are treated with a treating agent having two amino groups, and the magnetic metal compound particles are treated with a treating agent having one amino group.

Further, it is preferable that the non-magnetic metal compound particles have a functional group having a higher polarity after the lipophilic treatment than the magnetic metal compound particles. In particular, it is preferable that the non-magnetic metal compound particles are treated with a treating agent having an epoxy group, and the magnetic metal compound particles are treated with a treating agent having an amino group.

Examples of the lipophilic treatment agent having an amino group include γ
-Aminopropyltrimethoxysilane, γ-aminopropylmethoxydiethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ- Aminopropylmethyldimethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane,
Ethylenediamine, ethylenetriamine, styrene-
Dimethylaminoethyl (meth) acrylate copolymer, isopropyl tri (N-aminoethyl) titanate and the like are used.

As the lipophilic treatment agent having a mercapto group, mercaptoethanol, mercaptopropionic acid,
γ-mercaptopropyltrimethoxysilane or the like is used.

As the lipophilic treatment agent having an epoxy group,
γ-glycidoxypropylmethyldiethoxysilane, γ
-Glycidoxypropyltrimethoxysilane, β-
(3,4-epoxycyclohexyl) trimethoxysilane, epichlorohydrin, glycidol, styrene-
Examples thereof include glycidyl (meth) acrylate copolymer.

The resin used when the carrier of the present invention is used as a carrier core and the surface of the carrier core is treated with a resin to form a coated carrier is not particularly limited. Examples include polystyrene, acrylic resins such as styrene-acrylic copolymer, vinyl chloride, vinyl acetate, polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, solvent-soluble perfluorocarbon resin polyvinyl alcohol, polyvinyl acetal, polyvinylpyrrolidone, petroleum. Resin, cellulose, cellulose derivative, novolac resin, low molecular weight polyethylene, saturated alkyl polyester resin, aromatic polyester resin, polyamide resin, polyacetal resin, polycarbonate resin, polyether sulfone resin, polysulfone resin, polyphenylene sulfide resin, polyether ketone resin, Phenolic resin, modified phenolic resin, malein resin, alkyd resin, epoxy resin, acrylic resin, anhydrous malein and telef Unsaturated polyester obtained by polycondensation of acid and polyhydric alcohol, urea resin, melamine resin, urea-melamine resin, xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, acetoguanamine resin, glyptal resin, furan Examples thereof include resins, silicone resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyurethane resins and fluororesins.

Of these, silicone resins and fluororesins are preferably used from the viewpoints of adhesion to the core, prevention of spent, etc., and particularly preferred are silicone resins. Further, these can be used alone, but it is preferable to use them in combination with a coupling agent in order to enhance the film strength and control the preferable charging.

The coupling agent is preferably used as a so-called primer agent, a part of which is treated on the core surface before coating with the resin, whereby the resin layer is treated with a covalent bond. It can be formed in a state of high adhesion.

Aminosilane is preferably used as the coupling agent. As a result, an amino group having a positive charging property can be introduced on the carrier surface, and a desired charge amount can be imparted to the toner. Furthermore, when the metal compound particles are subjected to lipophilic treatment and a silicone resin is used as the coating layer of the carrier core, the presence of an amino group activates both the lipophilic treatment agent and the silicone resin. A stronger coating can be formed by further enhancing the adhesion to the carrier core and at the same time accelerating the curing of the silicone resin.

<2> Toner of the Present Invention The toner of the present invention contains at least a binder resin and a colorant. In the present invention, it is particularly effective to use a toner having a weight average particle diameter of 3 to 6 μm as a replenishing developer. When a toner having a particle size of less than 3 μm is used, the fluidity as a replenishment developer tends to be deteriorated, especially in a low humidity environment, and thus replenishment becomes unstable.
Further, the toner itself has a low handling property as a powder, and sometimes it may adhere to the wall of the replenishment developer container and cannot be completely discharged. If it exceeds 6 μm,
The collision energy between the carrier and the toner particles is likely to be large, and toner deterioration in the replenishment container is likely to occur. Further, since the fluidity tends to be high, the developer is likely to be biased due to the difference in specific gravity between the toner and the carrier in the supply container. In addition, since one toner particle becomes large in terms of developability, it is difficult to obtain a more detailed image with high resolution.
Further, when electrostatic transfer is performed, toner scattering easily occurs.

The particle size distribution of the toner is 2.52 μm.
It is preferable that the following toner particles are contained in an amount of 1.5 to 20% by number, and a cumulative value of 1.5 times the weight average particle diameter or more is included in an amount of 0.5 to 10%. If the number of toner particles having a particle size of 2.52 μm or less is less than 1.5% by number, the number of particles that contribute to the reproducibility and graininess of fine dots is reduced, which affects the image quality. Further, if it exceeds 20% by number, the fluidity deteriorates,
It may not be able to be completely discharged. Further, phenomena such as fogging and scattering occur during development, which also affects image characteristics. When the cumulative value of 1.5 times the weight average particle diameter or more is less than 0.5%, the fluidity is deteriorated, and the developer is likely to be densely clogged to easily cause agent deterioration. When it is more than 10%, the resolution is high,
It is difficult to obtain a more detailed image. Further, when electrostatic transfer is performed, toner scattering easily occurs.

As the binder resin for the toner, for example, polystyrene, poly-p-chlorostyrene, homopolymers of styrene such as polyvinyltoluene and its substitution products; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene. Copolymer, styrene-vinyl naphthalene copolymer, styrene-acrylic ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene -Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer Styrene-based copolymer; poly Vinyl; phenol resins; natural modified phenolic resins; natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins; polyester resins; polyurethane; polyamide resin; furan resins, epoxy resins, xylene resins;
Polyvinyl butyral; terpene resin; coumarone indene resin; petroleum resin can be used. Examples of preferable binder resins include styrene-based copolymers and polyester resins. A crosslinked styrene resin is also a preferable binder resin.

A styrene monomer and a styrene comonomer are used as the polymerizable monomer of the styrene copolymer, and the comonomer for the styrene monomer is
For example, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile,
A monocarboxylic acid having a double bond such as acrylamide or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and a substituted product thereof; Vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate; eg ethylene, propylene,
Ethylenic olefins such as butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; Used alone or in combination.

Further, the toner has a shape factor SF-1 of 10
It is more preferably 0 to 120. Shape factor SF-
In the case where 1 is more than 120, the fluidity of the developer tends to be large, and the charge amount is likely to change in the long-term durability test. A toner having an SF-1 in the range of 100 to 120 has a high transfer efficiency on paper, and even if the amount of toner to be placed on the photoconductor is small, it is possible to obtain the same density as that of the conventional toner, and therefore in terms of cost. It is advantageous.
In addition, since the packing density tends to be high, there are many opportunities for contact with the carrier and it is easy to always maintain stable charging.

A toner having a core / shell structure and having a core formed of a low softening point substance is also preferably used. The toner uses a low softening point substance, and is fixed at low temperature.
Although it is advantageous for oilless fixing, it tends to be disadvantageous to heat generation due to mechanical shear, and toner spent may occur due to agitation in the developing device. However, the use of the carrier of the present invention in combination eliminates the concern.

Solid wax is one of the low softening point substances.
-40 mass%, preferably 2-30 mass% is suitable. If the wax content is less than 1% by mass, the offset suppressing effect will be small, and if it exceeds 40% by mass, the wax will be unevenly distributed on the toner surface, and carrier contamination or the like will easily occur.

As a preferred wax, in the molecular weight distribution measured by gel permeation chromatography (GPC), the weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.45 or less, and the solubility parameter is 8.4. By using the wax of ~ 10.5, the toner has excellent fluidity, a uniform fixed image without uneven gloss can be obtained, and further, the heating member of the fixing device is less likely to be contaminated and the storability is deteriorated. And, when a full color OHP having excellent transparency of a fixed image and melting toner is prepared by melting the toner, a part or all of the wax appropriately covers the heating member and the toner is not offset. In addition to being able to produce full-color OHP and exhibiting good low-temperature fixability, it is possible to achieve a long service life of the pressure contact member. .

The wax contained in the toner used in the present invention has a weight average molecular weight (Mw) / number average molecular weight (Mn) of 1.45 or less in the molecular weight distribution by GPC using a double column, preferably 1. It is more preferably 30 or less from the viewpoints of uniformity of a fixed image, good transferability of toner, and prevention of contamination of a contact charging means for contacting and charging a photoreceptor.

When the Mw / Mn value of the wax exceeds 1.45, the fluidity of the toner decreases, and
The glossiness of the fixed image and the transferability of the toner are liable to be lowered, and the carrier is apt to be contaminated.

In the present invention, the molecular weight distribution of the wax is
It is measured under the following conditions by GPC using a double column.

(GPC measurement conditions) Apparatus: GPC-150C (manufactured by Waters) Column: GMH-HT 30 cm 2 series (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (addition of 0.1% ionol) Flow rate: 1 0.0 ml / min sample: A sample having a concentration of 0.15% is measured under the condition of 0.4 ml injection or more, and a molecular weight calibration curve prepared from a monodisperse polyurethane standard sample is used for calculating the molecular weight of the sample. Furthermore, the weight-average molecular weight and the number-average molecular weight are calculated by performing polyethylene conversion using a conversion formula derived from the Mark-Houwink viscosity formula.

The melting point of the wax used in the present invention is 4
It is preferably from 0 to 150 ° C, particularly preferably from 50 to 120 ° C. If the melting point of the wax is lower than 40 ° C, the blocking resistance of the toner will be weakened, the sleeve will be easily contaminated when a large number of sheets are copied, and the developer coat will become nonuniform when the image forming speed is changed. Density unevenness is likely to occur. If the melting point of the wax exceeds 150 ° C., excessive energy is required for uniform mixing with the binder resin in the toner production method by the pulverization method, and even in the toner production method by the polymerization method, the uniformization to the binder resin is required. for,
Increasing the viscosity of the device increases the size of the device or compatibilizes it.

The melting point of the wax is ASTM D3418.
It is the temperature of the main peak value in the endothermic curve measured according to -8.

For the measurement according to ASTM D3418-8, for example, Perkin Elmer DSC-7 is used. The melting point of indium zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat. An aluminum pan was used as a sample, and an empty pan was set as a control.
The measurement is performed in the range of 00 ° C.

In the present invention, the wax used is 100 ° C.
The melt viscosity in is preferably 1 to 50 mPa · s, more preferably a wax compound having 3 to 30 mPa · s.

When the melt viscosity of the wax is lower than 1 mPa · s, damage is likely to occur due to the shear force between the toner and the magnetic carrier when the toner is developed using the magnetic carrier, and the external additive may be buried or the toner may be crushed. It tends to occur, and it tends to be difficult to always coat a stable amount of developer for various image forming speeds. If the wax has a melt viscosity of more than 50 mPa · s, the viscosity of the dispersoid is too high when a toner is produced by a polymerization method, and it is easy to obtain a toner having a fine particle size and a uniform particle size. However, the toner tends to have a wide particle size distribution.

The melt viscosity of wax is measured by HAAKE.
Cone plate type rotor (PK
-1) is used for the measurement.

Further, the wax used in the present invention is
The molecular weight distribution measured by GPC has two or more peaks or one or more peaks and one or more shoulders, and in the molecular weight distribution, a weight average molecular weight (Mw)
Is 200 to 2000, and the number average molecular weight (Mn) is 150 to
It is preferably 2000. The above molecular weight distribution is
It has been found that either a single wax or a plurality of waxes may be achieved, resulting in a hindered crystallinity and a further improvement in transparency.

The method of blending two or more waxes is not particularly limited, but for example, a media type dispersing machine (ball mill, sand mill, attritor, apex mill, coball mill, handy mill) may be used at a temperature not lower than the melting point of the waxes to be blended. It is also possible to melt-blend with (1)), or to dissolve the wax to be blended in the polymerizable monomer and blend with a media-type disperser. At this time, a pigment, a charge control agent, or a polymerization initiator may be used as an additive.

The weight average molecular weight (Mw) of the wax is 20.
0-2000, number average molecular weight (Mn) is 150-200
Is preferred. More preferably Mw is 200-
1500, more preferably 300 to 1000, Mn is 200 to 1500, and more preferably 250 to 1000.
Good to be. Wax Mw is less than 200 or M
When n is less than 150, the blocking resistance of the toner may decrease. If the Mw of the wax is more than 2000 or Mn is more than 2000, the crystallinity of the wax itself may be developed and the transparency may be lowered.

Examples of the wax that can be used in the present invention include paraffin wax, polyolefin wax, modified products (for example, oxides and graft products), higher fatty acids, and metal salts thereof, amide waxes, and the like. And ester waxes. Among them, the ester wax is particularly preferable in that a higher quality full color OHP image can be obtained.

In these toners, at least silica fine particles, titanium oxide fine particles, and fine particles selected from the group consisting of a mixture thereof are preferably used as an external additive. The developer has fluidity and the environmental characteristics are improved.

Other external additives include metal oxide powder (aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitride powder (silicon nitride, etc.). ), Carbide powder (silicon carbide, etc.), metal salt powder (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salt powder (zinc stearate, calcium stearate, etc.), carbon black, silica powder, poly Fine powders of materials such as tetrafluoroethylene, polyvinylidene fluoride, polymethylmethacrylate, polystyrene, silicone are preferred. The number average particle diameter of the above-mentioned fine powder is preferably 0.2 μm or less. When the number average particle diameter exceeds 0.2 μm, the fluidity is lowered and the image quality is lowered during development and transfer. The method for measuring the average particle size is based on the method for measuring the metal oxide.

The external additive is used in an amount of preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the toner particles. The external additive is
They may be used alone or in combination. The external additive is preferably hydrophobized.

[0097] the external additive has a specific surface area by the nitrogen adsorption by the BET method is 30m ² / g or more, particularly 50~400m ² /
Those in the range of g are good.

The mixing process of the toner particles and the external additive can be carried out using a mixer such as a Henschel mixer.

As a method for producing a toner, a binder resin, a colorant, and other internal additives are melt-kneaded, the kneaded material is cooled and then pulverized and classified, or a suspension polymerization method is used to directly produce a toner. Method, a dispersion polymerization method in which a toner is directly produced using an aqueous organic solvent in which the obtained polymer is insoluble in the monomer, or a soap which is directly polymerized in the presence of a water-soluble polar polymerization initiator to produce a toner Examples thereof include a method of producing a toner by using an emulsion polymerization method represented by a free polymerization method.

In the present invention, a method for producing a toner by a suspension polymerization method under normal pressure or under pressure is preferred, which allows relatively easily obtaining a fine particle toner having a sharp particle size distribution and a particle size of 3 to 6 μm.

As a method of encapsulating the low-softening point substance in the toner particles, the polarity of the material in the aqueous medium is set to be smaller for the low-softening point substance than for the main monomer, and a smaller amount of the larger polarity is used. By adding a resin or a monomer, it is possible to obtain toner particles having a so-called core / shell structure in which a low softening point substance is coated with an outer shell resin. Toner particle size distribution control and particle size control are carried out by changing the type and amount of the sparingly water-soluble inorganic salt or dispersant that acts as a protective colloid, and mechanical device conditions such as roller peripheral speed, number of passes, stirring blades. A predetermined toner can be obtained by controlling the stirring conditions such as the shape, the shape of the container, the solid content concentration in the aqueous medium, and the like.

As the outer shell resin of the toner, styrene-
Examples thereof include (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers.
In the method of directly obtaining the toner by the polymerization method, those monomers are preferably used.

Specifically, styrene; o (m-, p-)
-Styrene monomers such as methyl styrene, m (p-)-ethyl styrene; methyl (meth) acrylate, (meth)
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid ester monomers such as 2-ethylhexyl, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylic acid amide. A monomer is preferably used.

Examples of the colorant used in the present invention include the following.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used.

Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 9
4, 95, 109, 110, 111, 128, 129,
147, 168 and the like.

Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I.
I. Pigment Red 3, 5, 6, 7, 23, 48:
2, 48: 3, 48: 4, 57: 1, 81: 1, 14
4, 166, 169, 177, 184, 185, 20
2,206,220,221,254 are particularly preferred.

Examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

These colorants can be used alone or in the form of a mixture, or in the state of a solid solution.

Examples of the black colorant include carbon black and the above-mentioned yellow / magenta / cyan colorants, which are toned to black.

In the case of color toner, the colorant is a hue angle,
It is selected from the viewpoints of saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner. The amount of the colorant added is the resin 10
It is used by adding 1 to 20 parts by mass to 0 parts by mass.

As the charge control agent used for the toner,
Known ones can be used. In the case of color toners, a charge control agent that is colorless or light-colored, has a high charging speed, and can stably maintain a constant charge amount is particularly preferable. Further, when the direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibitory property and having no solubilized product in an aqueous medium is particularly preferable.

For example, as negative charge control agents, metal compounds of salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid or their derivatives; polymeric compounds having sulfonic acid or carboxylic acid in the side chain; boron compounds; urea Compounds; silicon compounds; currys arenes and the like. As the positive charge control agent, a quaternary ammonium salt, a polymer type compound having the quaternary ammonium salt in its side chain, a guanidine compound, or an imidazole compound is preferably used.

The charge control agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin, and a metal compound of dialkyl salicylate is particularly preferably used.

When the toner particles are produced by the direct polymerization method, 2,2'-azobis-is used as the polymerization initiator.
(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1′-azobis (cyclohexane-1-carbonitrile, 2,2′-azobis-4-
Azo-based polymerization initiators such as methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; Such a peroxide type polymerization initiator is used.

The amount of the polymerization initiator added varies depending on the intended degree of polymerization, but is generally 0.5 to 2 with respect to the monomer.
0 mass% is added and used. Although the type of the polymerization initiator varies slightly depending on the polymerization method, it may be used alone or in combination with reference to the 10-hour half-life temperature. It is also possible to further add and use a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like for controlling the degree of polymerization.

When suspension polymerization is used as a method for producing a toner, an inorganic oxide is used as a dispersant to be used.
Tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina Etc. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like. These are used by dispersing them in the aqueous phase. These dispersants are used in an amount of 0.2 to 1 with respect to 100 parts by mass of the polymerizable monomer.
It is preferred to use 0.0 parts by weight.

As these dispersants, commercially available products may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, the inorganic compound may be formed in a dispersion medium under high speed stirring. I can. For example, in the case of tricalcium phosphate, a dispersant suitable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high speed stirring. Further, 0.001 to 0.1 part by mass of a surfactant for making these dispersants fine may be used in combination. Specifically, commercially available nonionic, anionic or cationic surfactants can be used, for example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate. , Calcium oleate is preferably used.

When the direct polymerization method is used as the toner manufacturing method, the toner can be specifically manufactured by the following manufacturing method. A monomer composition in which a release agent consisting of a low-softening substance, a colorant, a charge control agent, a polymerization initiator, and other additives are added to a monomer and uniformly dissolved or dispersed by a homogenizer or an ultrasonic disperser. Things,
It is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer, homomixer, homogenizer or the like. Granulation is carried out by adjusting the stirring speed and time so that the desired toner particle size, which is preferably a droplet of the monomer composition, is obtained.

After that, stirring may be carried out to the extent that the particle state is maintained and the particles are prevented from settling by the action of the dispersion stabilizer. Polymerization temperature is 40 ° C or higher, generally 50
Polymerization is performed by setting the temperature at 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and for the purpose of improving durability characteristics,
In order to remove unreacted polymerizable monomers, by-products, etc., the aqueous medium may be partially distilled off in the latter half of the reaction or after the reaction. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer system.

The toner may be classified to control the particle size distribution, and as a method therefor, preferably, a multi-division classification device utilizing inertial force is used. By using this apparatus, the toner having the particle size distribution preferable in the present invention can be efficiently manufactured.

The average particle size and particle size distribution of the toner were measured as follows.

1 to 5 ml of a surfactant (eg, alkylbenzene sulfonate) is added to 100 to 150 ml of pure water, and 2 to 20 mg of a measurement sample is added thereto. The electrolytic solution in which the sample is suspended is dispersed by an ultrasonic disperser for 1 to 3 minutes, and a laser scan particle size distribution analyzer CIS-1 is used.
00 (manufactured by GALAI) is used to measure the particle size distribution and the like.

In the present invention, particles of 0.5 to 60 μm are measured, the number average particle diameter and the weight average particle diameter measured under these conditions are determined by computer processing, and the number average particle diameter of the number average particle diameter is determined from the number-based particle size distribution. A cumulative ratio equal to or smaller than 1/2 the double diameter cumulative distribution is calculated to obtain a cumulative value equal to or smaller than the 1/2 double diameter cumulative distribution. Similarly, from the volume-based particle size distribution, the weight average particle size of 2
The cumulative ratio above the double diameter cumulative distribution is calculated, and the cumulative value above the double diameter cumulative distribution is calculated.

The toner shape factor SF-1 was FE-SEM (S-800) manufactured by Hitachi Ltd., and 300 or more toner images (magnification 300 times) were randomly sampled. The image was introduced into an image analyzer (Luze × 3) manufactured by Nireco Co., Ltd., and analyzed, and the value calculated by the following formula was defined as the toner shape factor SF-1. SF-1 = ((MXLNG) ² / AREA) × (π /
4) × 100 (In the formula, MXLNG indicates the maximum diameter of the toner, and AREA
Indicates the projected area of the toner. )

The method of measuring the triboelectric charge amount of toner is as follows.

Toner and carrier are mixed in an appropriate amount (2-1.
5% by mass) and mix with a turbula mixer to 1
Mix for 20 seconds. This mixed powder (developer) is added to the bottom 63
It is put in a metal container equipped with a 5-mesh conductive screen, sucked by a suction device, and the triboelectric charge amount is obtained from the difference in weight before and after suction and the potential accumulated in the capacitor connected to the container. At this time, the suction pressure is 250 mmHg. By this method, the triboelectric charge amount is calculated using the following formula. Q (μC / g) = (C × V) / (W1-W2) (where W1 is the mass before suction, W2 is the mass after suction, C is the capacity of the capacitor, and V is the capacitor). It is the accumulated potential)

<3> Replenishing Developer in the Present Invention In the present invention, when a toner and a carrier are mixed to prepare a replenishing developer, the mixing ratio is 1 part by mass of the carrier in the developer. Good results are obtained with a proportion of 2 to 50 parts by weight of toner. If the amount of toner is less than 2 parts by mass, the amount of charge of the developer is apt to increase because the amount of carrier is too large, and the image density changes.
On the other hand, if the amount exceeds 50 parts by mass, the toner amount becomes extremely large, the carrier is deteriorated, and the charge amount of the developer is apt to decrease.

<4> Image Forming Apparatus / Method Next, an image forming apparatus equipped with a developing device using the above-mentioned replenishment developer of the present invention will be described. FIG. 1 is a schematic configuration diagram of an electrophotographic full-color image forming apparatus equipped with a rotary rotation type developing device.

First, the electrostatic latent image carrier 1 is charged by the charging device 15
As a result, the surface thereof is uniformly charged with negative polarity. Next, the exposure device 14 performs image exposure corresponding to a first color, for example, a yellow image, and an electrostatic latent image corresponding to a yellow image is formed on the surface of the electrostatic latent image carrier 1.

The developing device 13 is of a rotational movement type, and the yellow developing device faces the electrostatic latent image carrier 1 before the tip of the electrostatic latent image corresponding to the yellow image reaches the developing position. After that, the magnetic brush rubs the electrostatic latent image to form a yellow toner image on the electrostatic latent image carrier.

In the developing device used for the above-mentioned development, for example, a developing sleeve, a supply roll, a magnet roll, a regulating member, a scraper and the like are provided inside the developing device. FIG. 2 is a schematic configuration diagram of the developing devices 2, 3, 4 and 5 in FIG. The flow of conveyance until the developer in the developing machine is developed will be described with reference to FIG.

The developing sleeve 6 contains a fixed magnet and is driven and rotated while maintaining a predetermined developing interval with 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 in a state where no developer intervenes, or is arranged with a predetermined distance from the developing sleeve 6. Etc. There are various things. The pair of 10 and 11 has a screw structure, and has a function of conveying and circulating the developer in opposite directions to sufficiently agitate and mix the toner and the carrier, and then to send the developer as a developer to the developing sleeve 6.
The magnet roll 8 is composed of, for example, 4-pole magnets of equal magnetic force in which N poles and S poles are alternately arranged at equal intervals, or a repulsive magnetic field is formed in a portion in contact with the scraper to separate the developer. In order to facilitate the above, one pole may be omitted to form five poles, and the developing sleeve 6 may be encapsulated in a fixed state.

The two developer agitating / conveying members 10 and 11 described above.
Is a member that also functions as a stirring member that rotates in mutually opposite directions, and conveys replenishment toner that is replenished from the toner storage device 9 by the thrust of the stirring screw.
By the mixing action of the toner and the magnetic carrier, a uniform two-component developer that has been triboelectrically charged is formed, and the developer is deposited on the peripheral surface of the developing sleeve 6 in layers. The developer on the surface of the developing sleeve 6 forms a uniform layer by the restriction member 7 having a double structure composed of a non-magnetic material and a magnetic material, which is provided so as to face the magnetic pole of the magnet roll 8. The uniformly formed developer layer develops the latent image on the peripheral surface of the electrostatic latent image carrier 1 in the developing area to form a toner image.

In FIG. 1, the transfer material 12 such as paper or a transparent sheet is conveyed from the paper feed tray 26 or 27 by the delivery roll 28 or 29, and once the front end is blocked by the registration roll 25, It is sent to the transfer drum 24 at a predetermined timing. The transferred transfer material 12 is transferred to the suction device 32 and the opposing roll 30.
By this, the transfer drum 24 is electrostatically held, and the transfer drum 24 and the electrostatic latent image carrier 1 are conveyed to a transfer area facing each other. Therefore, the transfer material comes into close contact with the yellow toner image on the electrostatic latent image carrier 1, the yellow toner image is transferred onto the transfer material 12 by the action of the transfer device 31, and the transfer drum 24.
Prepares for the next step while holding the transfer material 12.

After the transfer of the yellow toner, the electrostatic latent image carrier 1 is then subjected to cleaning pretreatment if necessary, and then the charge is removed by the charge removal corotron, and the yellow toner remaining on the surface by the cleaning device 18 is discharged. Are scraped off, and the charge remaining on the surface is removed by the charge removing device 16.

Next, for the second color, for example, magenta image forming process, the electrostatic latent image carrier 1 is charged by the charger 15.
The surface of the electrostatic latent image carrier 1 is uniformly charged with a negative polarity by the laser exposure device 14, and image exposure corresponding to a magenta image is performed by the laser exposure device 14. An electrostatic latent image corresponding to a magenta image is formed on the surface of the electrostatic latent image carrier 1. It is formed. Further, the developing device 13 is switched so that the magenta developing device faces the electrostatic latent image carrier 1 after the formation of the yellow toner layer is completed, and the electrostatic latent image corresponding to the magenta image is formed. The image is developed with a magenta magnetic brush. Then, the transfer material held on the transfer drum is conveyed again to the transfer area, and by the action of the transfer device 31, the magenta toner is multi-transferred onto the yellow toner this time.

After the transfer of the magenta toner, the electrostatic latent image carrier 1 is then cleaned of residual toner on the surface and discharged of residual charge in the same manner as in the yellow image forming step, while the magenta toner is discharged. The transfer material which has finished the transfer is prepared for the next step while being held on the transfer drum 24.

Thereafter, similarly to the magenta image forming step, an image forming step for the third color, for example, cyan is performed, and finally an image forming step for the fourth color, for example, black is performed. In the final black image forming step, the transfer material is conveyed differently from the steps up to the third color. That is, the transfer material that has finished the transfer of the fourth color is separated from the transfer drum 24 by the peeling static eliminator 19 and the peeling fingers (not shown) at the tips of the transport guide members 20, and the fixing device 21 transfers the multiple toner image to the transfer material. After being transferred to the image forming apparatus, it is carried out of the image forming apparatus.

The transfer drum 2 which has completed the separation of the transfer material
In No. 4, the surface is cleaned by the cleaning device 23 after the charge is removed by the charge removing devices 22 and 33, and the next transfer material 12 is awaited.

When the copying operation as described above is repeated,
The toner in the developer accommodated in the developing tank 17 in the developing device in FIG. 2 is gradually consumed, and the ratio of the toner to the carrier, that is, the toner concentration decreases. This change in toner concentration is feedback-controlled by a toner concentration sensor (not shown) provided in the developing tank 17 so that the toner concentration always falls within an appropriate range required for development. By the above control, the toner is supplied from the replenishing port of the toner replenishing section (toner containing device 9) to the developing tank 17 in the developing device.

On the other hand, the carrier in the developer in the developing tank 17 is not consumed by the development and is stirred together with the toner in the developing tank 17, the magnetic force of the magnet roll, and the electrostatic latent image. Due to the influence of contact with the carrier 1,
The surface is gradually polluted and deteriorates. As the carrier deteriorates in this way, it becomes impossible to impart a predetermined charge amount to the toner, resulting in deterioration of image quality. Therefore, it is necessary to replace the deteriorated carrier which is not consumed in the developing device with a new carrier. In FIG. 1, as means for replenishing a new carrier into the developing device, a toner cartridge for replenishing toner consumed by the development (toner containing device 9) and the replenishment toner and the above-mentioned predetermined amount of carrier. The developer mixed with is put into each of the developing devices 2 through the replenishing port of the toner containing device 9.
Supply 3, 4, 5 The excess developer is discharged from the developer-side developer discharge port as described below.

Therefore, the replacement of the developer utilizing the rotational movement in the rotationally moving developing device 13 shown in FIG. 1 will be described with reference to FIGS. In the full-color image forming apparatus using the developing device 13 that employs the rotational movement method, the developing devices 2, 3, 4, and 5 rotate and move inside the developing device 13 and face the electrostatic latent image carrier 1 during development. The electrostatic latent image carrier 1 is rotated and moved to a position for development, and when not developing
Rotate to a position not facing the.

At the position where the developing device 2 faces the electrostatic latent image carrier 1 and is performing the developing operation, the developer overflowing from the developing device side developer discharge port 34 provided in the developing device 2 is rotated. By the operation, it moves in the communication pipe 36 and is discharged from the developer recovery port 35 provided on the rotation center shaft of the rotary developing device switching device.

As the developing method using the magnetic carrier of the present invention, specifically, an AC voltage is applied to the developer carrying member to form an alternating electric field in the developing area, and the magnetic brush is applied to the photosensitive drum 1. It is preferable to perform development in the state of being in contact. The distance (SD distance) between the developer bearing member (developing sleeve) 6 and the photosensitive drum 1 is preferably 100 to 1000 μm in terms of preventing carrier adhesion and improving dot reproducibility. If it is narrower than 100 μm, the supply of the developer is likely to be insufficient and the image density becomes low, resulting in 1000
If it exceeds μm, the magnetic force lines from the magnetic pole S ₁ spread and the density of the magnetic brush becomes low, resulting in poor dot reproducibility, weakening of the force for restraining the magnetic coated carrier, and easy carrier adhesion.

The voltage between the peaks of the alternating electric field is 300 to 30.
00V is preferable, the frequency is 500 to 10000 Hz,
The frequency is preferably 1000 to 7000 Hz, and can be appropriately selected and used depending on the process. In this case, examples of the waveform of the AC bias for forming the alternating electric field include a triangular wave, a rectangular wave, a sine wave, and a waveform in which the duty ratio is changed. In order to cope with the change in the toner image forming speed, it is preferable to apply a developing bias voltage (intermittent alternating superposition voltage) having a discontinuous AC bias voltage to the developer carrying member to perform development. . If the applied voltage is lower than 300 V, it may be difficult to obtain a sufficient image density, and the fog toner in the non-image area may not be recovered well. On the other hand, if the voltage exceeds 3000 V, the latent image may be disturbed via the magnetic brush, resulting in deterioration of image quality.

By using a two-component type developer having a well-charged toner, the fogging removal voltage (Vback)
Can be lowered, and the primary charging of the photoconductor can be reduced, so that the life of the photoconductor can be extended. Vbac
Although k depends on the developing system, k is preferably 200 V or less, more preferably 150 V or less. The contrast potential is preferably 100 to 400 V so that a sufficient image density can be obtained.

If the frequency is lower than 500 Hz, it depends on the process speed, but when the toner contacting the electrostatic latent image carrier is returned to the developing sleeve, sufficient vibration is not given and fog is apt to occur. Become. 10000Hz
If it exceeds, the toner cannot follow the electric field and the image quality is apt to be deteriorated.

What is important in the developing method of the present invention is that the photosensitive drum 1 of the magnetic brush on the developing sleeve 11 is provided in order to obtain sufficient image density, excellent dot reproducibility, and development without magnetic carrier adhesion. The contact width with (developing contact portion) is preferably 3 to 8 mm. If the development contact area is narrower than 3 mm, it is difficult to satisfactorily satisfy the sufficient image density and dot reproducibility. If it is wider than 8 mm, packing of the developer occurs and the operation of the machine is stopped, and the magnetic carrier It becomes difficult to sufficiently suppress the adhesion.
As a method of adjusting the developing contact portion, the contact width is adjusted by adjusting the distance between the regulation blade 7 and the developing sleeve 6 or the distance between the developing sleeve 6 and the photosensitive drum 1 (SD distance). Can be adjusted appropriately.

The structure of the photosensitive member may be the same as that of the photosensitive member used in an image forming apparatus, and for example, a conductive layer, an undercoat layer, and a charge generating layer are formed on a conductive substrate such as aluminum or SUS in this order. , A charge transport layer, and a photoreceptor having a structure in which a charge injection layer is provided if necessary.

The conductive layer, the undercoat layer, the charge generation layer and the charge transport layer may be those usually used for a photoreceptor.

As the outermost surface layer of the photoreceptor, for example, a charge injection layer or a protective layer may be used.

In addition to the initial high image quality, by using the replenishing carrier of the present invention, the share of the developer in the developing device is small, and the toner or the external additive to the carrier can be used even when copying a large number of sheets. Etc. are suppressed,
Even with a small amount of the replenishing carrier, the effect of the present invention with little deterioration in image quality can be sufficiently exhibited.

The image forming method of the present invention will be further described with reference to the drawings.

In FIG. 5, a magnetic charging brush made of magnetic particles 123 is formed on the surface of the conveying sleeve 122 by the magnetic force of the magnet roller 112, and this magnetic brush is referred to as an electrophotographic photosensitive member (hereinafter referred to as "photosensitive member"). 1
The surface of the photosensitive member 101 is brought into contact with the surface of the photosensitive member 101 to charge it. A charging bias is applied to the carrying sleeve 111 by a bias applying unit (not shown). A laser beam 124 is applied to the charged photoconductor 101 by an exposure device (not shown).
Is irradiated to form a digital electrostatic latent image. The electrostatic latent image formed on the photoconductor 101 includes the magnet roller 112, and the toner 119a in the developer 119 carried on the developing sleeve 111 which is applied with a developing bias by a bias applying device (not shown) causes It is developed.

The developing device 104 is divided into a developer chamber R ₁ and a stirring chamber R ₂ by a partition wall 117, and developer conveying screws 113 and 114 are installed respectively. Stirring room R ₂
A toner storage chamber R ₃ accommodating the replenishment toner 118 is installed above, and a toner supply port 1 is provided below the storage chamber R _3.
20 are provided.

By rotating the developer carrying screw 113, the developer in the developer chamber R ₁ is carried in one direction along the longitudinal direction of the developing sleeve 111 while being stirred. The partition 1117 has openings (not shown) on the front side and the back side of the drawing, and the developer conveyed to _one of the developer chambers R ₁ by the screw 113 passes through the opening of the partition 117 on one side thereof. It is sent to the agitation chamber R ₂ and passed to the developer carrying screw 114. Screw 11
The rotation direction of 4 is opposite to that of the screw 113. While stirring and mixing the developer in the stirring chamber R ₂ , the developer transferred from the developer chamber R ₁ and the toner replenished from the toner storage chamber R ₃ , It is conveyed in the stirring chamber R ₂ in the opposite direction to the screw 113, and is fed into the developer chamber R ₁ through the other opening of the partition wall 117.

To develop the electrostatic latent image formed on the photoreceptor ₁ , the developer 119 in the developer chamber R ₁ is drawn up by the magnetic force of the magnet roller 112, and the developing sleeve 1
It is carried on the surface of 11. The developer carried on the developing sleeve 111 is conveyed to the regulating blade 115 as the developing sleeve 111 rotates, and is regulated by the developing agent thin layer having an appropriate layer thickness there. Reach the developing area facing each other. A magnetic pole (development pole) is provided at a portion corresponding to the development area of the magnet roller 112.
N ₁ is located, the developing pole N ₁ forms a developing magnetic field in the developing area, and this developing magnetic field causes the developer to stand up, and a magnetic brush of the developer is generated in the developing area. Then, the magnetic brush comes into contact with the photoconductor 101, and the toner attached to the magnetic brush and the developing sleeve 11 by the reversal development method.
The toner adhering to the surface of No. 1 is transferred to and adheres to the area of the electrostatic latent image on the photoconductor 101, and the electrostatic latent image is developed to form a toner image.

The developer that has passed through the developing area is returned to the developing device 104 as the developing sleeve 111 rotates.
It is peeled off from the developing sleeve 111 by the screw 113, dropped into the developer chamber R ₁ and the stirring chamber R ₂ , and collected.

When the T / C ratio (mixing ratio of toner and carrier, that is, toner concentration in the developer) of the developer 119 in the developing device 104 is reduced by the above development, replenishment development from the replenishment developer storage chamber R _{3 is performed.} The agent 118 was replenished to the stirring chamber R ₂ in an amount corresponding to the amount consumed in the development, and the carrier increased more than necessary was used as a deteriorated developer mixed with the toner to obtain 1
The developing device 1 is removed from the discharge screw 29 to the outside.
The T / C and carrier amount of the developer 119 in 04 are kept at a predetermined amount. T / of the developer 119 in the container 104
To detect the C ratio, a toner concentration detection sensor 128 that measures the change in the magnetic permeability of the developer using the inductance of the coil is used. The toner concentration detection sensor has a coil (not shown) inside.

The regulating blade 115 arranged below the developing sleeve 111 and regulating the layer thickness of the developer 119 on the developing sleeve 111 is a non-magnetic blade 115 made of a non-magnetic material such as aluminum or SUS316. The distance between the end and the surface of the developing sleeve 111 is 150.
˜800 μm, preferably 250 to 700 μm.
If this distance is less than 150 μm, the magnetic carrier aggregates and is clogged between the magnetic carriers to cause unevenness in the developer layer, and it is difficult to apply the developer necessary for good development, resulting in thin and uneven development. Images are easily formed.
In order to prevent uneven coating (so-called blade clogging) due to unwanted particles mixed in the developer, this distance is preferably 150 μm or more. If it is larger than 800 μm, the amount of the developer coated on the developing sleeve 111 increases and it is difficult to regulate the predetermined developer layer thickness, and the magnetic carrier particles adhere to the photoconductor 101 more and the developer circulates.
The development regulation by the regulation blade 115 is weakened, the toner tribo is reduced, and the fog is apt to occur.

Even if the developing sleeve 111 is rotationally driven in the direction of the arrow, this magnetic carrier particle layer is separated from the sleeve surface by the balance between the restraining force based on the magnetic force and gravity and the conveying force in the moving direction of the developing sleeve 111. Movement slows down. It falls under the influence of gravity.

The developed toner image is applied onto the transferred transfer material (recording material) 125 by the bias applying means 1.
The toner image transferred onto the transfer material by the transfer blade 127, which is a transfer means to which a transfer bias is applied by 26, is fixed onto the transfer material by a fixing device (not shown). In the transfer step, the transfer residual toner that has not been transferred to the transfer material and remains on the photoconductor 101 has its charge adjusted in the charging step and is collected during development.

FIG. 6 is a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus. The full-color image forming apparatus in FIG. 6 also does not have an independent cleaning unit for collecting and storing the transfer residual toner remaining on the photoconductor, and after the developing unit transfers the toner image onto the transfer material. The developing simultaneous cleaning method for collecting the toner remaining on the image carrier is performed.

The carrier increased in amount by the carrier contained in the replenishment developer overflows the capacity UP, is taken into the developer recovery auger, and is conveyed to the replenishment developer container or another recovery container.

The main body of the full-color image forming apparatus has a first image forming unit Pa, a second image forming unit Pb, and a third image forming unit Pb.
The image forming unit Pc and the fourth image forming unit Pd are provided side by side, and images of different colors are formed on the transfer material through the processes of latent image formation, development, and transfer.

The construction of each image forming unit provided in the image forming apparatus will be described by taking the first image forming unit Pa as an example.

The first image forming unit Pa comprises a photosensitive member 61a having a diameter of 30 mm as an electrostatic latent image carrier.
The photoconductor 61a is rotated in the direction of arrow a. The primary charging device 62a as a charging means is a photoconductor 61 that is a charging magnetic brush formed on the surface of a sleeve having a diameter of 16 mm.
It is arranged so as to contact the surface of a. Laser light 6
7a is irradiated by an exposure device (not shown) in order to form an electrostatic latent image on the photoconductor 61a whose surface is uniformly charged by the primary charger 62a. Photoconductor 61a
The developing device 63a as a developing means for developing the electrostatic latent image carried on the upper surface to form a color toner image is
Holds color toner. The transfer blade 64a as a transfer unit transfers the color toner image formed on the surface of the photoconductor 61a onto the surface of the transfer material (recording material) conveyed by the belt-shaped transfer material carrier 68. The transfer blade 64a can contact the back surface of the transfer material carrier 68 to apply a transfer bias.

The first image forming unit Pa forms an electrostatic latent image on the photoconductor by the exposure device 67a after uniformly charging the photoconductor 61a by the primary charger 62a.
The electrostatic latent image is developed with color toner by the developing device 63a, and the developed toner image is carried on the first transfer portion (contact position between the photosensitive member and the transfer material) to carry and convey the transfer material. Transfer blade 64 abutting on the back side of transfer material carrier 68
Transfer is applied to the surface of the transfer material by applying a transfer bias from a.

When the toner is consumed by the development and the T / C ratio is decreased, the decrease is detected by the toner concentration detecting sensor 85 which measures the change of the magnetic permeability of the developer by utilizing the inductance of the coil, and the toner is consumed. The toner is replenished from the replenishment toner container 65a according to the amount of toner. The toner concentration detection sensor 85 has a coil (not shown) inside.

This image forming apparatus has the same structure as the first image forming unit Pa, and has a second image forming unit Pb and a third image forming unit Pc in which the colors of the color toners held in the developing device are different. Four image forming units of the fourth image forming unit Pd are provided side by side. For example, yellow toner is used for the first image forming unit Pa, magenta toner is used for the second image forming unit Pb, cyan toner is used for the third image forming unit Pc, and black toner is used for the fourth image forming unit Pd. Transfer of each color toner onto the transfer material is sequentially performed at the transfer portion of each image forming unit. In this step, while matching the registration, the color toners are superposed on the same transfer material by one movement of the transfer material, and when completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. , The fixing device 70 by a conveying means such as a conveying belt.
Sent to the final full-color image with just one fusing.

The fixing device 70 has a pair of fixing rollers 71 having a diameter of 40 mm and a pressure roller 72 having a diameter of 30 mm.
The fixing roller 71 has heating means 75 and 76 inside.

The unfixed color toner image transferred onto the transfer material passes through the pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70, and is subjected to the action of heat and pressure on the transfer material. Is fixed in.

In FIG. 6, the transfer material carrier 68 is an endless belt-shaped member, and this belt-shaped member is moved in the direction of arrow e by a driving roller 80. In addition, a transfer belt cleaning device 79, a belt driven roller 81, a belt static eliminator 82, and a pair of registration rollers 83 are for transferring the transfer material in the transfer material holder to the transfer material carrier 68. .

As the transfer means, instead of the transfer blade contacting the back side of the transfer material carrier, a contact such as a roller-shaped transfer roller which contacts the back surface side of the transfer material carrier so that a transfer bias can be directly applied. It is possible to use transfer means.

Further, in place of the above contact transfer means, a contact bias is applied from a corona charger, which is arranged in non-contact on the back surface side of a transfer material carrier which is generally used, to perform transfer. It is also possible to use the above transfer means.

However, it is more preferable to use the contact transfer means because the amount of ozone generated when the transfer bias is applied can be controlled.

[0178]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited thereto.

Carrier Production Example 1 (i) Phenol 7.5 parts by mass (ii) Formalin solution 11.25 parts by mass (formaldehyde about 40%, methanol about 10%, balance water) (iii) γ-glycidoxypropyl 62 parts by mass of magnetite fine particles subjected to lipophilic treatment with 0.7% by mass of trimethoxysilane (average particle size 0.31 μm, specific resistance 5.5 × 10 ⁵ Ωcm) (iv) γ-glycidoxypropyltrimethoxysilane 1 26 parts by mass of α-Fe ₂ O ₃ fine particles subjected to lipophilic treatment at 0.2% by mass (average particle size 0.70 μm, specific resistance 2.3 × 10 ⁹ Ωcm) The magnetite and α-Fe ₂ O ₃ used here. The lipophilic treatment of 99.3 parts by mass of magnetite and α-Fe ₂ O ₃ 9
0.7 parts by weight for each of 8.8 parts by weight and 1.
It was carried out by adding 2 parts by mass of γ-glycidoxypropyltrimethoxysilane and premixing and stirring at 100 ° C. for 30 minutes in a Henschel mixer.

While maintaining the above materials and 11 parts by mass of water at 40 ° C., they were mixed for 1 hour. To this slurry, 2.0 parts by mass of 28% by mass ammonia water as a basic catalyst and 11 parts by mass of water were placed in a flask, heated and maintained at 85 ° C. for 40 minutes while stirring and mixing, and reacted for 3 hours,
A phenolic resin was produced and cured. Then, after cooling to 30 ° C. and adding 100 parts by mass of water, the supernatant was removed, the precipitate was washed with water and air-dried. Next, this was dried under reduced pressure (5 mmHg or less) at 160 ° C. to obtain magnetite fine particle-containing spherical magnetic carrier core particles using phenol resin as a binder resin.

Coarse particles were removed from the particles through a 60-mesh and 100-mesh sieve, and then a multi-division wind classifier (Elbow Jet Lab EJ-L-3, manufactured by Nittetsu Mining Co., Ltd.) utilizing the Coanda effect was used. Fine powder and coarse powder were removed by using to obtain carrier core particles having a volume average particle diameter of 37 μm.

The obtained carrier core particles were placed in a coater, and then 0.3% by mass of γ-aminopropyltrimethoxysilane diluted with a toluene solvent was continuously applied to the core surface while applying a shear stress. Processed. In addition, at that time, it was carried out at 40 ° C. and 500 torr (66.5 kPa) under a dry nitrogen stream while volatilizing the solvent. Subsequently, a mixture of 0.8% by mass of straight silicone resin having all methyl groups as substituents and 0.015% by mass of γ-aminopropyltrimethoxysilane was coated with toluene as a solvent.

Further, this magnetic coated carrier was
Coated carrier No. 2 was baked at 100 ° C., the coarse particles agglomerated were cut with a 100-mesh sieve, and then fine particles and coarse particles were removed by a multi-division air classifier to adjust the particle size distribution. 1
Got The obtained carrier No. The production method and physical properties of No. 1 are shown in Tables 1 and 2.

Carrier Production Example 2 In Carrier Production Example 1, the lipophilic treatment agent for magnetite was changed to 0.7 part by weight of γ-aminopropyltrimethoxylane, and the abundance ratio of magnetite and hematite was 80 /.
In the same manner as in Carrier Production Example 1, except that the coated carrier No. 20 was changed. Got 2. The obtained carrier No. The production method and physical properties of No. 2 are shown in Tables 1 and 2.

Carrier Production Example 3 In Carrier Production Example 1, the lipophilic treatment agent for magnetite was added to 0.7 parts by mass of γ-aminopropyltrimethoxysilane, and the lipophilic treatment amount of hematite was adjusted to 1.5 parts by mass. With the exception of changing the abundance ratio of magnetite and hematite to 90/10, the same procedure as in Carrier Production Example 1 was performed. Got 3. The obtained carrier No. Three
The production method and physical properties of are shown in Tables 1 and 2.

Carrier Production Example 4 Fe ₂ O ₃ = 73 mol% and MnO = 27 mol% in molar ratio
Were weighed and mixed using a ball mill. After calcining this at 1000 ° C., the calcinable material was crushed by a ball mill. 100 parts by mass of the obtained powder, 0.5 parts by mass of sodium polymethacrylate and water were put into a wet ball mill and mixed to obtain a slurry. The obtained slurry was granulated with a spray dryer. Carrier production example 1 after sintering this at 1200 ° C.
In the above, the same coating treatment was carried out except that the amount of the methyl silicone resin was changed to 1.5% by mass to obtain a coated carrier 4. The production method and physical properties of the obtained carrier 4 are shown in Tables 1 and 2.

Carrier Production Example 5 Carrier Production Example 1 was the same as Carrier Production Example 1 except that the abundance ratio of magnetite and hematite was changed to 40/60 and the amount of methyl silicone resin added was changed to 1.2% by mass. Similarly, the coated carrier No. Got 5.
The obtained carrier No. The production method and physical properties of No. 5 are shown in Tables 1 and 2.
Shown in.

Carrier Production Example 6 Weighed so that Fe ₂ O ₃ = 50 mol%, CuO = 27 mol% and ZnO = 23 mol% in molar ratio, and mixed using a ball mill. After calcining this at 1000 ° C., the calcinable material was crushed by a ball mill. 100 parts by mass of the obtained powder, 0.5 parts by mass of sodium polymethacrylate and water were put into a wet ball mill and mixed,
A slurry was obtained. The obtained slurry was granulated with a spray dryer. After sintering this at 1200 ° C., except that the amount of aminosilane added as a primer agent in Carrier Production Example 1 was changed to 0.15% by mass and the amount of methyl silicone resin was changed to 0.5% by mass, The coat treatment was performed to obtain a coat carrier 6. The production method and physical properties of the obtained carrier 6 are shown in Tables 1 and 2.

Carrier Production Example 7 In Carrier Production Example 1, the particle size of hematite was 0.5.
μm (specific resistance 2.0 × 10 ⁹ Ωcm), and the same procedure as in Carrier Production Example 1 except that the lipophilic treatment amount was changed to 0.7 parts by mass. Got 7. The obtained carrier No. The production method and physical properties of No. 7 are shown in Tables 1 and 2.

Carrier Production Example 8 Carrier Production Example 6 except that the amount of aminosilane added as a primer agent was 0.3% by mass and the amount of methyl silicone added was 2.0% by mass. In the same manner as in No. 6, coated carrier No. Got 8. The obtained carrier No. The production method and physical properties of No. 8 are shown in Tables 1 and 2.

Carrier Production Example 9 -Terephthalic Acid Trimellitic Anhydride / Propylene Oxide Polyester Resin Containing Derivative of Bisphenol A Addition 19 parts by mass Cu-Zn ferrite 80 parts by mass 1 quaternary ammonium salt compound 1 part by mass Henschel The mixture was thoroughly premixed with a mixer, melt-kneaded with a twin-screw extruder, cooled, roughly crushed to about 1 to 2 mm with a hammer mill, and then finely crushed with a fine crusher using an air jet system. Further, after classifying the finely pulverized product obtained, 0.8% by mass of 0.02 μm styrene / methyl methacrylate copolymer resin particles
Was dry coated with a hybridizer (manufactured by Nara Machinery Co., Ltd.) to obtain a magnetic coated carrier No. Got 9. The obtained magnetic coated carrier No. The production method and physical properties of No. 9 are shown in Tables 1 and 2.

Carrier Production Example 10 Coated carrier No. 10 was prepared in the same manner as in Carrier Production Example 9 except that the classification conditions were changed and the particle size distribution shown in Table 1 was used. Got 10.
The obtained magnetic coated carrier No. The production method and physical properties of No. 10 are shown in Tables 1 and 2.

Carrier Production Example 11 Coated carrier No. 9 was prepared in the same manner as in Carrier Production Example 9 except that the classification conditions were changed and the particle size distribution shown in Table 1 was used. I got 11.
The obtained magnetic coated carrier No. The production method and physical properties of No. 11 are shown in Tables 1 and 2.

Carrier Production Example 12 A coated carrier No. 1 was prepared in the same manner as in Carrier Production Example 1 except that the coating treatment was changed to 0.8% by mass of the fluoroacrylic resin. I got 11. The obtained carrier No. The production method and physical properties of No. 11 are shown in Table 1.
And 2 are shown.

Carrier Production Example 13 Coated carrier No. 1 was prepared in the same manner as in Carrier Production Example 1 except that the coating resin was changed to 0.8% by mass of the polyester resin. I got 12.
The obtained carrier No. The production method and physical properties of No. 12 are shown in Tables 1 and 2.

[0196]

[Table 1]

[0197]

[Table 2]

Toner Production Example 1 (crushed toner 1) Polyester resin (condensation polymer of propoxylated bisphenol A and fumaric acid, acid value 10.8 mgKOH / g) 100 parts by mass C.I. I. Pigment Blue 15: 3 3 parts by mass, aluminum compound of dialkyl salicylic acid 5 parts by mass, low molecular weight polypropylene 5 parts by mass The above materials are mixed by a Henschel mixer, and the vent port is connected to a suction pump to suck the biaxial extruder. Melt kneading was performed. The melt-kneaded product was crushed with a hammer mill to obtain a crushed product having a mesh pass of 1 mm. Further, after finely pulverizing with a jet mill, classification was performed with a multi-division classifier (Elbow Jet) to obtain cyan toner particles.

To 100 parts by mass of the cyan toner particles, hydrophobized titanium oxide fine powder (BET: 90 m ² /
g) with 1.0 part by mass of hydrophobized silica fine powder (BE
T: 130 m ^{2 /} g) 1.0 part by mass was mixed by a Henschel mixer, and a cyan toner No. 1 having a weight average particle diameter of 5.4 μm was obtained. Got 1. The obtained toner No. The physical properties of No. 1 are shown in Table 3.

Toner Production Example 2 (Pulverized Toner 2) In the toner production example 1, the conditions of pulverization and classification of the melt-kneaded product were changed so that only 2.0 parts by mass of the hydrophobized titanium oxide fine powder was used as the external additive. Cyan Toner No. 2 having a weight average particle diameter of 2.8 μm was manufactured in the same manner as in Toner Production Example 1 except that the toner was changed. Got 2. The obtained toner No. The composition and physical properties of No. 2 are shown in Table 3.

Toner Production Example 3 (Pulverized Toner 3) In the toner production example 1, the pulverization and classification conditions of the melt-kneaded product were changed, and the external additive was hydrophobized silica fine powder 2.0.
Cyan Toner No. 5 having a weight average particle diameter of 5.9 μm was manufactured in the same manner as in Toner Production Example 1 except that only parts by weight were changed. Got 3. The obtained toner No. The composition and physical properties of No. 3 are shown in Table 3.

Toner Production Example 4 (Pulverized Toner 4) In the toner production example 1, the conditions of pulverization and classification of the melt-kneaded product were changed, and the external additive was hydrophobized silica fine powder 2.0.
Cyan Toner No. 6 having a weight average particle diameter of 6.5 μm was manufactured in the same manner as in Toner Production Example 1 except that only parts by weight were changed. Got 4. The obtained toner No. The composition and physical properties of No. 4 are shown in Table 3.

Toner Production Example 5 (Pulverized Toner 5) In the toner production example 1, the pulverization and classification conditions of the melt-kneaded product were changed, and the external additive was hydrophobized silica fine powder 2.0.
Cyan Toner No. 6 having a weight average particle diameter of 6.0 μm was manufactured in the same manner as in Toner Production Example 1 except that only parts by weight were changed. Got 5. The obtained toner No. Table 3 shows the composition and physical properties of No. 5.

Toner Production Example 4 (Polymerized Toner 1) To 710 parts by mass of ion-exchanged water, 450 parts by mass of a 0.1 M Na ₃ PO ₄ aqueous solution was added, and the mixture was heated to 60 ° C., followed by TK.
1200 using a homo-mixer (made by Tokushu Kika Kogyo)
Stirred at 0 rpm. 68 parts by mass of 1.0 M-CaCl ₂ aqueous solution was gradually added to this to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

Styrene 165 parts by mass n-butyl acrylate 35 parts by mass C.I. I. Pigment Blue 15: 3 (colorant) 10 parts by mass, dialkyl salicylate metal compound (charge control agent) 5 parts by mass, saturated polyester (polar resin) 10 parts by mass, ester wax (melting point 70 ° C.) 50 parts by mass On the other hand, the above materials Was heated to 60 ° C. and uniformly dissolved and dispersed at 11000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo). 10 parts by mass of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in this to prepare a polymerizable monomer composition.

The above polymerizable monomer composition was put into an aqueous medium and stirred at 60 ° C. under N ₂ atmosphere with a TK type homomixer at 11000 rpm for 10 minutes to prepare a polymerizable monomer composition. Grained. Then, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours while stirring with a paddle stirring blade. After completion of the polymerization reaction, residual monomers were distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water,
After drying, cyan toner particles were obtained.

With respect to 100 parts by mass of the obtained cyan toner particles, hydrophobized titanium oxide fine powder (BET: 90 m
² / g) and 1.0 part by mass of hydrophobized silica fine powder (B
ET: 130 m ^{2 /} g) 1.0 part by mass of externally added cyan toner No. 5 having a weight average particle diameter of 5.5 μm. Got 6. The obtained toner No. Table 3 shows the composition and physical properties of No. 6.

[0208]

[Table 3]

[Example 1] Carrier No. 1 (92 parts by mass) and toner No. 1 Cyan developer A was prepared by mixing 6 (8 parts by mass) with a V-type mixer. On the other hand, the carrier No. 1
(1 part by mass) and toner No. 6 (10 parts by mass) was mixed with a V-type mixer to obtain a replenishing cyan developer a.

The obtained two-component developer A was modified into a commercially available copying machine GP55 (manufactured by Canon Inc.) so that the image device shown in FIG. 5 could be inserted, and a developing sleeve of SUS with a diameter of 16 mm was used.
The sleeve was modified by sandblasting so that the surface shape was adjusted to have a surface roughness Rz = 10.8 μm. Further, the photoconductor was rotated at 150% in the opposite direction with respect to the contact portion. Further, as the charging member, magnetic particles are used by using the magnetic brush charger shown in FIG. 5, and the magnetic particles are rotated at 100% in the opposite direction to the contact portion of the photoconductor, and a DC / AC electric field (−700 V, (1.5 kHz / 1.0 kVpp) is applied in a superimposed manner to charge the photoconductor. Further, the cleaning unit is removed, the developing contrast is set to 250 V and the reverse contrast to the fog is set to −150 V, and the developing bias having the discontinuous AC voltage shown in FIG. Both the heating roller and the pressure roller have a surface layer of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) of 1.2 μm.
Image formation was performed using a modified image forming apparatus by changing to a covered roller.

An original original having an image area of 30% was used, a paper passing test was conducted at an image forming speed of 180 mm / sec, and the transfer efficiency at room temperature and low humidity (23 ° C./5% RH)
Evaluate charge stability, carrier adhesion, image density,
The charging stability, carrier adhesion, toner scattering, fog, and image density under high temperature and high humidity (32.5 ° C./80% RH) were evaluated based on the following evaluation methods.

(Image forming conditions) In the charging step, OP
The following magnetic particles were used for the magnetic brush charging device for charging the C photosensitive drum.

Preparation of Magnetic Particles 5 parts by mass of MgO, 8 parts by mass of MnO, 4 parts by mass of SrO, F
After each 83 parts by mass of e ₂ O ₃ was atomized, water was added and mixed, granulated, and then calcined at 1300 ° C. to adjust the particle size, and then ferrite magnetic particles with an average particle size of 28 μm (σ
₁₀₀₀ is 60 Am ² / kg, coercive force is 4.38 × 10 ^-1 k
A / m [= 55 Oersted]) was obtained.

The transfer efficiency was evaluated by performing a copy test on 30,000 sheets at room temperature and low humidity, forming a solid black image on the photosensitive drum, and collecting the solid black image with a transparent adhesive tape. Image density (D1) is measured by color reflection densitometer (col
or reflection densitometer
X-RITE 404A manufactured
by X-Rite Co. ). Next, a solid black image is formed again on the photosensitive drum, the solid black image is transferred to the recording material, and the solid black image transferred on the recording material is sampled with a transparent adhesive tape, and the image density (D2 ) Was measured. The transfer efficiency was calculated from the obtained image densities (D1) and (D2) based on the following formula. Transfer efficiency (%) = (D2 / D1) × 100

The charge stability was evaluated by performing a copying test on 30,000 sheets under normal temperature and low humidity and high temperature and high humidity, and evaluating the charge stability from the change in the charge amount of the developer. The evaluation was performed based on the following criteria, in which the change range between the charge amount at the time of copying 1000 sheets and the charge amount at the end is expressed in%. A: Change range of charge amount is 0 to 10% B: Change range of charge amount is 11 to 20% C: Change range of charge amount is 21 to 30% D: Change range of charge amount is 31 to 40% E: Change range of charge amount is 41 to 50% F: Change range of charge amount is 51% or more

For the carrier adhesion, after performing a copying test of 30,000 sheets at room temperature and low humidity and at high temperature and high humidity, a solid white image is formed on the photosensitive drum, and a photosensitive area between the developing section and the transfer section is exposed. Collect the part on the drum with a transparent adhesive tape, 5 cm
The number of magnetic carriers adhering to the photosensitive drum in × 5 cm was counted, and the number of adhering carrier particles per 1 cm ² was calculated. A: Less than 3 B: 3 to 5 C: 6 to 10 D: 11 to 15 E: 16 to 20 F: 21 or more

As for the toner scattering, after developing 30,000 sheets under high temperature and high humidity, the developing device is taken out and set in the idle rotation machine. Place the A4 paper centered right under the sleeve of the developing unit, 1
After performing idle rotation for 0 minutes, the weight of the toner dropped on the paper was measured and evaluated according to the following criteria. A: 3 mg or less B: 4 to 6 mg C: 7 to 9 mg D: 10 to 12 mg E: 13 to 15 mg F: 16 mg or more

Regarding fog, a reflection densitometer (densitometer TC6MC: Tokyo Denshoku Gijutsu Center) was used under high temperature and high humidity, and the reflection density of a blank sheet and the reflection of the non-image part in the 30,000th image Measure the concentration,
The difference between the reflection densities of the two was evaluated based on the reflection density of white paper. A: 0.5% or less B: 0.6 to 1.0% C: 1.1 to 1.5% D: 1.6 to 2.0% E: 2.1 to 4.0% F: 4 1% or more

Regarding the image density, a solid black image was copied at the initial temperature and after the copying of 30,000 sheets under normal temperature and low humidity and high temperature and high humidity.
reflection densitometer X
-RITE 404A manufactured b
y X-Rite Co. ).

The evaluation results are shown in Table 4. In addition, in the above evaluation results A to F, A to C were set to practical levels.

[Examples 2 to 12 and Comparative Examples 1 to 8] Table 4
In place of the combination of the carrier and the toner as shown in (1), images were produced and evaluated in the same manner as in Example 1 except that the developers B to T and the replenishment developers b to t were obtained. The evaluation results are shown in Table 4.

[0222]

[Table 4]

[0223]

Since the replenishment developer of the present invention has the above-mentioned constitution, the chargeability of the toner is stabilized and the good image quality can be obtained for a long period without being influenced by the environment.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an image forming apparatus equipped with a rotary rotation type developing device in which a replenishing developer of the present invention is used.

FIG. 2 is a diagram showing an embodiment of the developing device shown in FIG.

FIG. 3 is an enlarged configuration diagram for explaining the developing device in FIG.

FIG. 4 is a diagram showing one embodiment of the developing device of FIG.

FIG. 5 is a diagram showing an embodiment of an image forming apparatus including a developing device used in the cleanerless system of the present invention.

FIG. 6 is a diagram showing one embodiment of a full-color image forming apparatus of the present invention.

FIG. 7 shows a bias having a discontinuous AC electric field of a developing bias used in the image forming apparatus used in FIG.

[Explanation of symbols]

1 photosensitive drum 2,3,4,5 developing device 6 Development sleeve 7 regulation blade 8 magnet roller 9 Replenishment developer accommodating device 10, 11 developer transport screw 12 Transfer material 13 Development device 14 Exposure means 15 Roller charging device 17 Development tank 18,23 Cleaning device 19, 22, 33 Static eliminator 20 Transport guide buzz member 21 Fixing machine 24 Transfer drum 25 cash register roller 26,27 paper feed tray 28,29 Feed roller 30 opposing rollers 31 Transfer device 32 Adsorption device 34 Developer outlet 35 developer recovery port 37 Developer Primary Storage Section 38 Developer Recovery Auger

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Okado             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2H005 AA15 BA03 BA06 BA07 BA15                       CA11 CA12 CA15 CB03 CB04                       CB10 EA01 EA02 EA05 EA07                       EA10

Claims (13)

[Claims] 1. The toner has a weight average particle diameter of 3 to 6 μm.
The toner of 2.52 μm or less is 1.5 to 20% by number, the cumulative value of 1.5 times the weight average particle diameter or more is 0.5 to 10% by volume, and the carrier is an electric field. Strength 10
The specific resistance R ₁₀₀₀ at the time of applying 00 (V / cm) is 1 × 10 ¹⁰ ≦ R ₁₀₀₀ ≦ 1 × 10 ¹⁵ , and the carrier and the toner are parts by mass, and 2 to 50 parts of the toner are mixed with 1 part of the carrier. A replenishing developer, characterized in that it is contained in a ratio. 2. The electric field strength of the carrier is 1000 (V / V).
cm), the specific resistance when applied is R ₁₀₀₀ , 3000 (V /
cm), where R _3,000 is a specific resistance when applied, 1.0 ≦ log (R ₁₀₀₀ ) / log (R ₃₀₀₀ ) ≦ 1.3 is satisfied, the replenishment developer according to claim 1. . 3. The replenishment developer according to claim 1, wherein the carrier has a metal compound content in carrier particles of 80 to 95% by mass. 4. The carrier is 1000 / 4π (kA /
m) has a magnetization intensity σ ₁₀₀₀ of 35 to 75 (Am ²
/ Kg), The replenishment developer according to any one of claims 1 to 3. 5. The carrier is 1000 / 4π (kA /
m) has a magnetization intensity σ ₁₀₀₀ of 45 to 75 (Am ²
/ Kg), The replenishment developer according to any one of claims 1 to 3. 6. The carrier is 1000 / 4π (kA /
m) has a magnetization strength σ ₁₀₀₀ of 50 to 75 (Am ²
/ Kg), The replenishment developer according to any one of claims 1 to 5. 7. The carrier is 20 μm according to a mesh method.
The content of carrier particles of m or less is 0.01 to 10% by mass.
And the content of carrier particles of 74 μm or more is 0.1
The replenishment developer according to any one of claims 1 to 6, wherein the content of the replenishment developer is from 20 to 20% by mass. 8. The replenishment developer according to claim 1, wherein the carrier is a magnetic substance dispersion type resin carrier in which metal compound particles are dispersed in a binder resin. . 9. The replenishment developer according to claim 8, wherein the binder resin of the carrier is a thermosetting resin. 10. The replenishment developer according to claim 8, wherein the binder resin of the carrier is a phenol resin. 11. The replenishment developer according to claim 1, wherein the surface of the carrier is treated with a resin and / or a coupling agent. 12. The replenishment developer according to claim 11, wherein the resin is a silicone resin or a fluororesin. 13. The replenishment developer according to claim 11, wherein the coupling agent is aminosilane.