JP2859635B2 - Two-component developer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a two-component developer for visualizing an electrostatic latent image in an image forming method such as electrophotography and electrostatic recording.

[Related Art] In recent years, with the widespread use of electrophotographic copying machine image forming apparatuses, their applications have been diversified and the demands on image quality have become strict. 2. Description of the Related Art In copying images such as ordinary documents and books, it is required to reproduce very finely and faithfully without crushing or breaking even fine characters. In particular, when the latent image on the photosensitive member of the image forming apparatus is a line image having a size of 100 μm or less, thin line reproducibility is generally poor, and the sharpness of the line image is not yet sufficient. Recently, in an image forming apparatus such as an electrophotographic printer using a digital image signal, a latent image is formed by collecting dots of a constant potential, and a solid portion, a halftone portion, and an equal portion are formed by dots. Expressed by changing the density. However, in a state where the toner particles do not adhere to the dots and the toner particles protrude from the dots, it is not possible to obtain the gradation of the toner image corresponding to the dot density ratio of the black portion and the white portion of the digital latent image. There is a problem. Further, when the resolution is improved by reducing the dot size in order to improve the image quality, the reproducibility of a latent image formed from minute dots becomes more difficult, and the resolution and gradation are poor. Images tend to be poor.

Although the image quality is good at the beginning, the image quality may deteriorate while copying or printing out is continued. It is considered that this phenomenon occurs because only toner particles which are easily developed are consumed first while copying or printing is continued, and toner particles having poor developability accumulate and remain in the developing machine.

Heretofore, some developers have been proposed for the purpose of improving image quality. JP-A-51-3244 proposes a non-magnetic toner intended to improve image quality by regulating the particle size distribution. In the toner, 8 to
The main component is a toner having a particle size of 12 μm, which is relatively coarse. According to the study of the present inventors, it is difficult to achieve “density” on a latent image with a particle size of 30 μm.
From the characteristic that the particle size distribution is not more than 5% by number when the particle size is 20% or more, the particle size distribution is also broad, which tends to lower the uniformity. In order to form a clear image using such a coarse toner particle and a toner having a broad particle size distribution, it is necessary to fill the gap between the toner particles by thickly overlapping the toner particles. There is also a problem that it is necessary to increase the image density, and the amount of toner consumption required to obtain a predetermined image density increases.

Further, Japanese Patent Application Laid-Open No. 54-72054 proposes a non-magnetic toner having a sharper distribution than the former,
The size of particles having an intermediate weight is as coarse as 8.5 to 11.0 μM, and there is still room for improvement as a high-resolution toner.

In Japanese Patent Application Laid-Open No. 58-1229437, the average particle size is 6 to 10 μm.
Non-magnetic toners having the largest number of particles of 5 to 8 μm have been proposed, but the number of particles of 5 μm or less is as small as 15% by number or less, and an image lacking sharpness tends to be formed.

According to the study of the present inventors, it has been found that toner particles having a size of 5 μm or less clearly reproduce the outline of the latent image and have a main function of dense toner adhesion to the entire latent image. In particular, in the electrostatic latent image on the photoreceptor, due to the concentration of lines of electric force, the contour edge portion has a higher electric field strength than the inside, and the sharpness of the image quality is determined by the quality of the toner particles collected in this portion. According to the study by the present inventors, it has been found that the amount of particles of 5 μm or less is effective in solving the problem of sharpness of image quality.

To achieve high image quality, toner particles having a particle size of 5 μm or less are important. However, when the content of these toner particles is increased, the cohesiveness tends to increase and the developability tends to decrease.

[Problems to be Solved by the Invention] An object of the present invention is to provide a two-component developer which has solved the problems described above.

It is a further object of the present invention to provide a two-component developer having a high image density, particularly excellent fine line reproducibility and gradation.

It is a further object of the present invention to provide a two-component developer which does not change its performance over a long period of use.

It is a further object of the present invention to provide a two-component developer having no change in performance with respect to environmental fluctuations.

A further object of the present invention is to provide a two-component developer having excellent transferability.

A further object of the present invention is to provide a two-component developer capable of obtaining a high image density with a small consumption.

Still another object of the present invention is to provide a two-component developer capable of forming a toner image having excellent resolution, gradation, and fine line reproducibility even in an image forming apparatus using a digital image signal. .

[Means and Actions for Solving the Problems] Specifically, the present invention relates to a two-component developer having a carrier coated with a toner and a resin, wherein 60.0 toner particles having a particle size of 5 μm or less %, The coefficient of variation of the volume distribution of the toner (the standard deviation of the volume distribution / the volume average particle size) is 22.5 to 26.0, the volume average particle size of the toner is 4.00 to 6.00 μm, and the toner has fluidity. The present invention relates to a binary developer, wherein an inorganic compound fine powder as an agent is externally added, and the carrier has a volume average particle diameter of 10 to 80 μm.

The toner of the present invention having the above particle size distribution can faithfully reproduce even a fine line of a latent image formed on a photoreceptor, and can reproduce a dot latent image such as a halftone dot and a digital image. Gives an image having excellent gradation and resolution. Furthermore, even if copy or printout is continued, high image quality is maintained, and even if the image has a high density,
Good development can be performed with less toner consumption than conventional toners, which is advantageous in terms of economy and downsizing of a copying machine or a printer body.

The reason why such an effect is obtained in the two-component developer of the present invention is not necessarily clear, but is presumed as follows.

That is, in the two-component developer of the present invention, 5 μm
One feature is that toner particles having the following particle diameters are at least 60.0% by number. Conventionally, in toner, toner particles having a particle size of 5 μm or less are difficult to control the charge amount, impair the fluidity of the toner, and as a component that scatters the toner and soils the machine, and further as a component that causes image fogging. It was thought that aggressive reduction was necessary.

However, the present inventors have found that toner particles having a size of 5 μm or less are essential components for forming high-quality images.

For example, using a toner having a particle size distribution ranging from 0.5 μm to 30 μm, the surface potential on the photoreceptor is changed, and from a large development potential contrast in which a large number of toner particles are easily developed, to a halftone, and further, a very small amount of toner is used. A latent image with a changed surface potential on the photoreceptor was developed to a small development potential contrast in which only particles were developed, and the developed toner particles on the photoreceptor were collected, and the toner particle size distribution was measured. Many particles, especially 5μ
It was found that there were many toner particles of m or less. That is,
When toner particles having a particle size of 5 μm or less, which are most suitable for development, are smoothly supplied to the development of the latent image on the photoreceptor, the toner is faithful to the latent image, does not protrude from the latent image, and has truly excellent reproducibility. An image is obtained.

The toner particles having a particle size of 5 μm or less strictly cover the latent image and have a capability of faithfully reproducing the latent image. However, in the latent image itself, the electric field intensity at the peripheral edge portion is higher than that in the central portion. In some cases, the toner particles may be thinner on the inside than on the edges, and the image density may appear lighter. In particular, toner particles of 5 μm or less have a strong tendency,
It had to be less than a few percent. However, the present inventors have set the volume average particle size to 4.00 to 60.0 μm near 5 μm, remove the toner having a particle size apart from the volume average particle size, and set the variation coefficient of the volume distribution to 27.5 or less, preferably 27 or less. 27 or less, more preferably 22.5 to as shown in the Examples below
We found that 26.0 solves this problem and makes it clearer.

That is, it is considered that the toner particles having a particle size of 5 μm or less have a moderately controlled charge amount by adopting such a volume average particle size and a particle size distribution. Since the toner is supplied to the inner side where the electric field intensity is smaller, a uniform developed image is formed by compensating for the small amount of the toner particles on the inner side with respect to the edge portion, and as a result, the resolution and the gradation are increased at a high density. Thus, a sharp image having excellent properties is provided.

By a completely different concept from the conventional viewpoint, the toner of the present invention can solve the conventional problems and can withstand recent severe demands for high image quality.

 The configuration of the present invention will be described in more detail.

A toner containing 60.0% by number or more of a toner having a particle diameter of 5 μm or less is extremely excellent in fine line reproducibility, resolution, and gradation, but gradually deteriorates as copying or printing is continued. . For particles having a particle size of 5 μm or less, the presence of relatively large or small particles tends to cause agglomeration of the toner particles. Or the density difference between the edge portion and the inside of the latent image is increased, so that the image tends to be slightly hollow.

Therefore, it is necessary that the variation coefficient of the volume distribution is 27 or less and the volume average particle size is 4.00 to 6.00 μm. If the variation coefficient of the volume distribution is larger than 27.5, the particle size difference between the particles constituting the toner becomes large, and an aggregation state is easily generated.

Further, in the case of such a particle size distribution, the charge balance of the toner particles is deteriorated, and a small-sized toner having a charge larger than necessary is charged and adheres to the developing sleeve, and the toner is transferred to the developing sleeve of the normal toner. Of the toner, and a toner having a large particle diameter, which is insufficiently charged, covers the toner layer, so that the developing property tends to decrease and the image density tends to decrease.
Accordingly, it is desirable to reduce the number of particles having a small particle size, and it is preferable that the number of toner particles having a size of 2.00 to 2.52 μm is 12% by number or less.

The volume average diameter of the toner is 4.00 to 6.00 μm, and this value cannot be considered separately from the above-described components. If the volume average particle diameter is less than 4.00 μm, in applications having a high image area ratio such as a graphic image, the problem that the amount of toner on the transfer paper is small and the image density is low tends to occur. This is considered to be due to the same reason as described above for lowering the density inside the edge portion of the latent image. If the volume average particle diameter exceeds 6.00 μm, 5
Since the number of particles having a relatively large particle size with respect to the particles having a particle size of μm or less increases, the image quality is liable to deteriorate at the beginning of copying if the use is continued at best.

The particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using a Coulter counter.

In other words, the Coulter Counter TA is used as a measuring device.
-Type II (manufactured by Coulter, Inc.) was connected to an interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon). Prepare a% NaCl aqueous solution. As a measuring method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was treated with an ultrasonic
After a dispersion treatment for minutes, the Coulter Counter TA-II
According to the mold, the particle size distribution of the particles of 2 to 40 μm was measured on the basis of the number by using a 100 μm aperture as the aperture, and then the value according to the present invention was obtained.

As a binder resin used in the toner of the present invention, when a heating / pressing roller fixing device having an oil applying device is used, the following binder resins for toner can be used.

For example, polystyrene, poly-p-chlorostyrene,
Styrenes such as polyvinyltoluene and their substituted homopolymers; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate 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 Styrene-based copolymers such as copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers; polyvinyl chloride, phenolic resins, naturally-modified phenolic resins, natural-resin-modified maleic resins, acrylic resins, methacrylic resins, Polyvinyl acetate, silicone Down resin, polyester resin, polyurethane, polyamide resins, furan resins, epoxy resins,
Xylene resin, polyvinyl butyral, terpene resin,
Coumarone indene resin, petroleum resin and the like can be used.

In a heating roller fixing method in which almost no oil is applied, so-called offset phenomenon in which a part of the toner image on the toner image support member is transferred to the roller, and adhesion of the toner to the toner image support member are important issues. . Toners that fix with less thermal energy tend to block or cake during steady-state storage or in a developing device, and these problems must also be considered at the same time. Therefore, in the present invention, when using the heating / pressing roller fixing method in which almost no oil is applied, the selection of the binder resin is more important. Preferred binders include crosslinked styrenic copolymers or crosslinked polyesters.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, and 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, maleic acid, butyl maleate, Dicarboxylic acids having a double bond such as methyl maleate, dimethyl maleate and the like and their substituted products; for example, vinyl chloride, vinyl acetate,
Vinyl esters such as vinyl benzoate; ethylene olefins such as ethylene, propylene, butylene; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone; vinyl methyl ether, vinyl ethyl ether; Vinyl monomers such as vinyl isobutyl ether and the like; alone or two or more vinyl monomers are used.

Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene and the like; for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate Double bonds such as 1,3-butanediol dimethacrylate, etc.
Carboxylic acid esters having two or more compounds; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups are used alone or as a mixture.

When a pressure fixing method is used, a binder resin for a pressure fixing toner can be used. For example, polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer , An ionomer resin, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a linear saturated polyester, and paraffin.

In the toner of the present invention, it is preferable that a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition). The charge control agent enables optimal charge control according to the development system.
In particular, in the present invention, it is possible to further stabilize the balance between the particle size distribution and the load, and by using a charge control agent, the function separation for improving the image quality according to each particle size range described above is performed. And mutual complementarity can be clarified. Examples of the positive charge control agent include denatured products such as nigrosine and resin acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; dibutyltin oxide and dioctyl Diorganotin oxides such as tin oxide and dicyclohexyltin oxide; dibutyltin borate;
Diorganotin borates such as dioctyl tin borate and dicyclohexyl tin borate can be used alone or in combination of two or more. Among these,
Charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

Also, the general formula R ₁ : H, CH ₃ R ₂ , R ₃ : a homopolymer of a monomer represented by a substituted or unsubstituted alkyl group (preferably, C _{1 to} C ₄ ): or styrene or acrylate as described above; Copolymers with polymerizable monomers such as methacrylates can be used as positive charge control agents, in which case these charge control agents also act as (all or part of) the binder resin .

As the negative charge controlling agent that can be used in the present invention, for example, an organometallic complex and a chelate compound are effective, and examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and 3,5-ditert-butyl. There are chromium salicylate and the like, particularly preferred are monoazo metal complexes, acetylacetone metal complexes, naphthoic acid and salicylic acid-based metal complexes or salts, and particularly preferred are salicylic acid-based metal complexes or salicylic acid-based metal salts, and monoazo metal complexes.

The above-mentioned charge control agent (having no action as a binder resin) is preferably used in the form of fine particles. In this case, specifically, the number average particle diameter of the charge control agent is preferably 4 μm or less (more preferably 3 μm or less).

When internally added to the toner, such a charge control agent is used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) based on 100 parts by weight of the binder resin.
Parts by weight).

Further, the two-component developer of the present invention contains an inorganic compound fine powder as a fluidity-imparting agent in order to prevent agglomeration even after long-term use.

In the two-component developer having the particle size distribution characteristic of the present invention, the specific surface area is larger than that of the conventional toner.

When the toner particles are easily agglomerated, or when the toner particles are brought into contact with the carrier or the surface of the cylindrical conductive sleeve having a magnetic field generating means inside due to triboelectric charging,
The number of times of contact between the surface of the toner particles and the carrier or the sleeve is increased as compared with the conventional toner, and wear of the toner particles and contamination of the surface of the carrier or the sleeve are liable to occur. Aggregation and abrasion are remarkably reduced by interposing the inorganic compound fine powder between the toner particles of the present invention and the toner particles in which the inorganic compound fine powder is combined or between the toner particles and the carrier or sleeve surface. As a result, spent can be suppressed, the life of the toner, the carrier and the sleeve can be prolonged, and the stable chargeability can be maintained, and the two-component developer having the toner and the carrier which is more excellent for long-term use. It is possible. Further, the toner particles having a particle diameter of 5 μm or less, which play a major role in the present invention, exhibit more effects in the presence of the inorganic compound fine powder, and can stably provide high-quality images.

The following compounds are preferably used as these inorganic compounds.

Oxides such as SiO ₂ , GeO ₂ , TIO ₂ , SnO ₂ , Al ₂ O ₃ , B ₂ O ₃ , P ₂ O ₅ , As ₂ O ₃ ; silicates, borates, phosphates, germanic acid Metal oxide salts such as salts, borosilicates, aluminosilicates, alumina borates, alumina borosilicates, tungstates, molybdates, tellurates; and composites thereof; silicon carbide, silicon nitride, amorphous Carbon or the like is used alone or in combination.

As the inorganic compound fine powder, any of inorganic compound fine powders produced by a dry method and a wet method can be used.

The dry method referred to here is a method for producing inorganic compound fine powder generated by vapor phase oxidation of a halogen compound. For example, in a method utilizing a thermal decomposition oxidation reaction of a halide gas in oxygen-hydrogen, the basic reaction formula is as follows.

MX _n + 1 / 2nH ₂ + 1 / 4O ₂ → MO ₂ + nHCl In this formula, for example, M is a metal or metalloid element, X is a halogen element, and n is an integer. Specifically, when AlCl ₃ , TiCl ₄ , GeCl ₄ , SiCl ₄ , POCl ₃ , and BBr ₃ are used, Al ₂ O ₃ , TiO ₂ , GeO ₂ , P ₂ O ₅ , and B ₂ O ₃ are obtained, respectively.

At this time, a composite compound can be obtained by using a mixture of halides.

Alternatively, fine powders can be obtained by a dry process by applying a manufacturing method such as thermal CVD or plasma CVD. Among them, Si
O ₂ , Al ₂ O ₃ , TiO _{2 and the} like are preferably used.

On the other hand, as a method for producing the inorganic compound fine powder used in the present invention by a wet method, various conventionally known methods can be applied. For example, the decomposition of sodium silicate with an acid is represented by the following general reaction formula.

Na ₂ O ・ XSiO ₂ + HCl + H ₂ O → SiO ₂・ nH ₂ O + NaCl In addition, decomposition of sodium silicate by ammonium salts or alkali salts, formation of alkaline earth metal silicate from sodium silicate and decomposition by acid Silicate, a method in which a sodium silicate solution is converted into silicate using an ion exchange resin, a method in which natural silicate or silicate is used, and the like.

Other methods include hydrolysis of metal alkoxides. The general reaction formula is shown below.

M (OR) _n + 1 / 2nH ₂ O → MO ₂ + nROH In this formula, for example, M is a metal or metalloid element, R is an alkyl group, and n is a reaction formula representing an integer. At this time, a composite can be obtained by using two or more metal alkoxides.

The Among the inorganic compound fine powder, the specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more (especially 50 to 400 m ² /
g), those having an average primary particle size of 0.2 μm or less (particularly 0.1 μm or less) give good results. Toner 100
The inorganic compound fine powder is used in an amount of 0.1 to 8 parts by weight, preferably 0.2 to 5 parts by weight, based on parts by weight.

When the toner of the present invention is used as a positively chargeable two-component developer, the inorganic compound fine powder added to prevent wear of the toner and contamination of the carrier and sleeve surfaces is negatively charged. Rather, it is preferable to use positively charged inorganic compound fine powder without impairing the charging stability.

As a method of obtaining the finely-charged inorganic compound fine powder, a method of treating the above-mentioned untreated fine inorganic compound powder with a silicon oil having an organo group having at least one nitrogen atom in a side chain, or a method of containing nitrogen There is a method of treating with a silane coupling agent or a method of treating with both.

In the present invention, the positively charged inorganic compound fine powder,
A substance having a positive triboelectric charge on an iron powder carrier when measured by a blow-off method.

As the silicone oil having a nitrogen atom in the side chain used for treating the inorganic compound fine powder, a silicone oil having at least a partial structure represented by the following formula can be used.

(Wherein, R ₁ represents hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, R ₃ and R ₄ represents hydrogen, an alkyl group or an aryl group,, R ₅ Represents a nitrogen-containing heterocyclic group) The alkyl group, the aryl group, the alkylene group, and the phenylene group may have an organo group having a nitrogen atom, or a substituent such as halogen as long as the chargeability is not impaired. May be provided.

Further, the nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

R _m -Si-Y _n (R represents an alkoxy group or a halogen, Y represents an organo group having at least one amino group or a nitrogen atom, m and n is an integer of 1 to 3 m + n =
4. Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there is an unsaturated heterocyclic group or a saturated heterocyclic group, and known ones can be applied. Examples of the unsaturated heterocyclic group include the following.

Examples of the saturated heterocyclic group include the following.

The heterocyclic group used in the present invention is preferably a 5- or 6-membered ring in consideration of stability.

Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, Butylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-
γ-propylphenylamine, trimethoxysilyl-γ
-Propyl benzylylamine and the like, and the nitrogen-containing heterocyclic ring may have the above-mentioned structure. Examples of such compounds include trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propyl Morpholine, trimethoxysilyl-γ-propylimidazole and the like.

The amount of the treated positively charged inorganic compound fine powder to be applied is 0.1 to 8 parts by weight with respect to 100 parts by weight of the toner, and is particularly effective when 0.2 to 5 parts by weight is added. It shows a positive chargeability having stable stability. In a preferred embodiment, the addition form is such that 0.2 to 3 parts by weight of the treated inorganic compound fine powder adheres to the surface of the toner particles with respect to 100 parts by weight of the toner. The untreated inorganic compound fine powder described above can be used in the same application amount.

Further, the inorganic compound fine powder used in the present invention is treated with a silane coupling agent, a treating agent such as silicon oil or an organosilicon compound for the purpose of hydrophobizing, or a combination of various treating agents, if necessary. It may be treated with the treating agent that reacts or physically adsorbs the inorganic compound fine powder. Examples of such a treating agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, Bromomethyldimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule, Is a dimethylpolysiloxane containing a hydroxyl group bonded to one Si each.

The silicone oil is generally represented by the following formula.

Preferred silicone oils are those having a viscosity of about 5 to 5000 cSt at 25 ° C., for example, methyl silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chlorophenylmethyl silicone oil, alkyl-modified silicone oil, and fatty acid-modified silicone oil. And polyoxyalkylene-modified silicone oils. These are used alone or as a mixture of two or more.

Further, in the present invention, fine powder of a fluorine-containing polymer,
For example, it is preferable to add fine powder of polytetrafluoroethylene, polyvinylidene fluoride or the like and a tetrafluoroethylene-vinylidene fluoride copolymer. In particular, polyvinylidene fluoride fine powder is preferred in terms of fluidity and abrasiveness. The amount added to the toner is 0.
01 to 2.0 wt%, particularly preferably 0.02 to 1.0 wt%.

In particular, in the toner in which the inorganic compound fine powder and the fine powder are combined, the reason is not clear, but stabilizes the state of the fine powder attached to the toner, for example, the attached fine powder is released from the toner. In addition, the effect on toner abrasion and sleeve fouling is not reduced, and the charging stability can be further increased.

The toner of the present invention may be mixed with additives as needed. As the colorant, conventionally known dyes and pigments can be used, for example, carbon black, magnetite, maghemite, hematite, phthalocyanine Blue, peacock blue, permanent red, lake red, rhodamine lake, Hanza yellow, permanent yellow, benzidine yellow and the like can be widely used.

As its content, 0.5 to 2.
0 parts by weight, in order to further improve the transparency of the OHP film, preferably 12 parts by weight or less, more preferably 0.5 to
9 parts by weight is good.

Other additives include, for example, lubricants such as zinc stearate, abrasives such as cerium oxide and silicon carbide, or fluidity-imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black, tin oxide and the like. And the like.

Further, in order to improve the releasability at the time of hot roll fixing, a wax-like substance such as low molecular weight polyethylene, low separation polypropylene, microcrystalline wax, carnauba wax, sasol wax, paraffin wax, etc.
Addition of about 5 wt% to the toner is also a preferred embodiment of the present invention.

Examples of the carrier that can be used in the present invention include iron powder,
Magnetic powders such as ferrite powders and nickel powders, glass beads and the like, and those obtained by treating the surfaces thereof with a resin or the like can be used. Carrier for 10 parts by weight of toner
It is good to use 10 to 1000 parts by weight (preferably 30 to 500 parts by weight). The volume average particle size of the carrier is preferably 10 to 80.
μm, more preferably 20 to 60 μm, in matching with a small particle size toner.

The carrier used in the present invention is preferably coated with a resin and / or a silicone compound in order to further stabilize the triboelectrification of the toner used in the present invention and faithfully develop a latent image.

In the toner having the particle size distribution according to the invention, since the toner tends to be spent, it is preferable to coat the toner with a carrier in order to prevent this.

There is also an advantage in durability when applied to high-speed machines.
Further, it can be performed for the purpose of controlling the charge of the toner.

As the resin for forming the coating phase of the carrier, for example, a silicone compound, a fluorine resin, or the like can be preferably used.

Examples of the fluorine-based resin for forming the carrier coating layer include, for example, polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, a halofluoropolymer such as polytrifluorochloroethylene, polytetrafluoroethylene, and polyperfluorocarbon. Orpropylene, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and trifluorochloroethylene, copolymer of tetrafluoroethylene and hexafluoropropylene, vinyl fluoride and fluoride Copolymer with vinylidene, copolymer with vinylidene fluoride and tetrafluoroethylene, copolymer with vinylidene fluoride and hexafluoropropylene, terpolymer of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomer Fluoroterpolymers such as Etc. are preferably used.

The weight average molecular weight of the fluoropolymer is 50,000 to 40
0,000 is preferred. More preferably, it is 100,000-250,000.

In forming the coating layer of the carrier, the above-mentioned fluorine-based resins may be used alone, or a blend of these may be used. In addition, those obtained by blending other polymers with these may be used.

As other polymers, homopolymers or copolymers of the following monomers are used.

Styrene derivatives such as styrene, α-methylstyrene, p-methylenestyrene, pt-butylstyrene, p-chlorostyrene, methyl methacrylate, ethyl methacrylate, prolyl methacrylate, butyl methacrylate, pentyl methacrylate, methacrylic acid Hexyl, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, Ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate,
Methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyl methacrylate Ethyl, N-vinyl-2-pyrrolidone methacrylate, methacrylonitrile, methacrylamide, N-methylol methacrylamide, ethyl methacrylate morpholine, diacetone acrylamide, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, Pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, Le acid decyl, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate,
Butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene acrylate Glycol, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl-2-pyrrolidone acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N- Methylol acrylamide, diacetone acrylamide, ethyl acrylate morpho Vinyl monomer having one vinyl group in one molecule such as ethylene glycol, vinyl pyridine, etc., or a reaction product of divinylbenzene, glycol with methacrylic acid or acrylic acid, for example, ethylene glycol dimethacrylate, 1,3-butylene glycol Methacrylate, 1,4
-Butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate,
Diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, neopentyl glycol ester hydroxypivalate dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, pentaerythrit tetramethacrylate,
Tris methacryloxyethyl phosphate, tris (methacryloyloxyethyl) isocyanurate, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, neopentyl glycol hydroxypivalate Diacrylate, trimethylolethane triacrylate,
Trimethylolpropane triacrylate, pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, tris (methacryloyloxyethyl) isocyanurate, glycidyl methacrylate and half-esterified methacrylic acid or acrylic acid, bisphenol type epoxy resin and methacrylic acid or acrylic Acrylic monomers having two or more vinyl groups in one molecule such as half-esterified acids, glycidyl acrylate and half-esterified methacrylic acid or acrylic acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, Hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate Pills, hydroxybutyl methacrylate, acrylic monomers having a hydroxyl group such as methacrylic acid -2-hydroxy-3-phenyl propyl and the like.

These vinyl monomers are copolymerized by a known method such as suspension polymerization, emulsion polymerization, and solution polymerization. These copolymers preferably have a weight average molecular weight of 10,000 to 70,000. The copolymer may be crosslinked with melamine aldehyde or isocyanate.

The blend ratio of the fluororesin and other polymer is 20 to 8
0:80 to 20% by weight, particularly preferably 40 to 60:60 to 40% by weight.

As the silicon-based compound for forming the coating layer of the carrier, for example, all polysiloxanes such as dimethylpolysiloxane and phenylmethylpolysiloxane are used, and alkyd-modified silicon, epoxy-modified silicon, polyester-modified silicon, and urethane-modified Modified resins such as silicon and acryl-modified silicon can also be used.

As the modified form, any of a block copolymer, a graft copolymer, a comb-shaped graft polysiloxane and the like can be used.

When applying to the actual magnetic particle surface, the magnetic particles are formed by varnishing a silicone resin such as solid methyl silicon varnish, solid phenyl silicon varnish, solid methyl phenyl silicon varnish, solid ethyl silicon varnish, and various modified silicon varnishes. A method of dispersing the varnish therein, a method of spraying a varnish onto the magnetic particles, and the like are employed.

As the material of the core material of the carrier used in the present invention,
For example, metals such as iron, nickel, cobalt, manganese, chromium, rare earth, and their alloys or oxides whose surface is oxidized or not oxidized can be used, and ferrite particles are more preferable than metal oxides.

 There is no particular limitation on the manufacturing method.

When the volume average particle diameter of the carrier is 10 to 80 μm (more preferably, 20 to 60 μm), the carrier is difficult to be developed (transferred together with the toner) on the latent image holding member, and the latent image holding member and the cleaning blade are not easily damaged. , The carrier holds the toner well, unevenness of solid image, toner scattering,
Fogging is unlikely to occur. Such a carrier core material,
It may be composed of only a magnetic material, may be composed of a combination of a magnetic material and a non-magnetic material, or may be a mixture of two or more magnetic particles.

As a method of coating the surface of the above-mentioned carrier core material with the coating resin, an outer resin is dissolved or suspended in a solvent, applied to the core material surface, and the resin is adhered to a core material made of magnetic particles or the like. The method is preferred.

In general, the amount of the coating resin to be treated is desirably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier core material in view of the film forming property and durability of the coating material.

To prepare the toner for developing an electrostatic image according to the present invention, a vinyl-based, non-vinyl-based thermoplastic resin, a pigment or dye as a colorant as needed, a charge control agent, other additives, etc. After sufficiently mixing with a mixer such as a heating roll, a kneader, a hot kneader such as an extruder is used to melt, knead, and knead the resin to make the pigments or dyes compatible with each other. The toner according to the present invention can be obtained by dispersing or dissolving, and after cooling and solidifying, performing pulverization and strict classification.

Further, the toner of the present invention requires particularly strict classification. For this purpose, a pulverizing step is also important, and in order to perform strict classification, it is necessary to sharpen the particle size distribution of the fine powder as much as possible. For this purpose, before fine grinding, 2mm or less,
It is desirable to crush it to preferably 1 mm or less, more preferably 0.5 mm or less. In addition, a medium crushing process was introduced,
It is particularly desirable to pulverize to about 100 μm and then pulverize.

In this way, by finely pulverizing from a small particle size,
By sharpening the particle size distribution of the finely pulverized product, it becomes possible to strictly classify into the particle size distribution characteristic of the present invention by the classification step.

Alternatively, after dispersing the constituent materials in the adhesive resin solution, a method of obtaining a toner by spray drying, or a predetermined material is mixed with a monomer to constitute the adhesive resin to form an emulsified suspension. Later, a polymerization method of producing a toner by polymerizing the toner, or a method of including a predetermined material in the core material, the shell material, or both in a so-called microcapsule toner composed of a core material and a shell material is known. Can be applied.

The two-component developer of the present invention uses a non-magnetic toner and magnetic particles and can be used in a normal two-component image forming method. In particular, a magnetic particle restraining member is provided opposite to a toner carrying member. A magnetic brush of magnetic particles is formed by a magnetic force of a magnetic field generating means upstream of the magnetic particle restraining member with respect to the moving direction of the surface of the holding member, and the magnetic brush is restrained by the magnetic particle restraining member; Is formed on the toner holding member, and the non-magnetic toner is developed on the surface of the latent image holding member by applying an alternating electric field.

This developing method will be described with reference to FIG. First
In the figure, 1 is a latent image holding member, 2 is a developer supply container,
3 is a non-magnetic sleeve, 4 is a fixed magnet, 5 is a magnetic or non-magnetic blade, 6 is a member for limiting a magnetic particle circulation area, 7 is a magnetic particle, 8 is a toner, 9 is a developer collecting container section, and 10 is scattering prevention. Reference numeral 11 denotes a magnetic member, 13 denotes a developing area, and 12 denotes a bias power supply. The sleeve 3 rotates in the direction b, and the magnetic particles 7 circulate in the direction c accordingly. As a result, contact and rubbing between the sleeve surface and the magnetic particle layer occur, and a developer layer is formed on the sleeve surface. Further, while the magnetic particles circulate in the c direction, a part of the magnetic particles is magnetic or non-magnetic blade 5 and sleeve 3.
Is regulated to a predetermined amount by the gap, and is applied on the developer layer. That is, the developer is applied to both the surface of the sleeve and the surface of the magnetic particles, and an effect equivalent to substantially increasing the surface area of the sleeve is exhibited.

In the developing region 13, one of the magnetic poles of the fixed magnet 4 is opposed to the latent image surface to form a clear developing pole, and the alternating electric field causes the toner to fly and develop on the sleeve and the magnetic particles. (This phenomenon will be described later.) After the development, the magnetic particles and the undeveloped toner are collected in the developing container with the rotation of the sleeve.

The sleeve 3 may be a paper cylinder or a cylinder made of a synthetic resin. However, if the surface of these cylinders is subjected to a conductive treatment or is made of a conductor such as aluminum, brass or stainless steel, it can be used as a developing electrode roller.

In the present invention, fine line reproducibility was measured by the following method. In other words, an image obtained by copying an original original of a fine line accurately having a width of 50 μm under appropriate copying conditions as a measurement sample, and using a Luzex 450 particle analyzer as a measuring device, a line width is determined by an indicator from an enlarged monitor image. Measurement. At this time, since the line width measurement position has irregularities in the width direction of the thin line image of the toner, the average line width of the irregularities is used as the measurement point. From this, the value (%) of the fine line reproducibility is calculated by the following equation.

In the present invention, the resolution was measured by the following method. In other words, a pattern consisting of five thin lines with the same line width and spacing, 3.6, 4.0, 4.5, 5.0, 5.6, 6.3,
Create an original image that is drawn to be 7.1, 8.0, 9.0 or 10.0 lines. Observe an image obtained by copying the original manuscript with these 10 line images under appropriate copying conditions with a magnifying glass, and determine the resolution value with the number of images (lines / mm) in which fine lines are clearly separated. I do.

 A large number indicates that the resolving power is high.

Hereinafter, the present invention will be described specifically with reference to Examples, but these Examples do not limit the present invention in any way. All parts in the following formulations are parts by weight.

[Example] Example 1 After the above materials were mixed well in a blender, they were kneaded with a biaxial kneading extruder set at 150 ° C. After cooling the obtained kneaded material and coarsely pulverizing it to 1 mm or less with a cutter mill, finely pulverizing it with a fine pulverizer using a jet stream, the obtained finely pulverized powder with a fixed wall type air classifier. Classification produced a classified powder. In addition, the obtained classified powder is strictly classified and removed simultaneously by a multi-division classifier using a Coanda effect (an elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.), and the black powder having a volume average particle size of 5.34 μm is removed. A fine powder (toner) was obtained.

For reference, a classification process using a multi-divided classifier is schematically shown in FIG. 2, and a cross-sectional perspective view (three-dimensional view) of the multi-divided classifier is shown in FIG.

To 100 parts of the obtained black fine powder toner, 1.0 part of positively charged hydrophobic dry silica (BET specific surface area: 200 m ^{2 /} g) was added and mixed with a Henschel mixer. Further, 10 parts of this toner was added to vinylidene fluoride. -Tetrafluoroethylene copolymer (monomer polymerization weight ratio 75/27), styrene-methyl methacrylate copolymer (monomer polymerization weight ratio 70/0)
90 parts of a ferrite carrier (volume average particle size: 50 μm) coated with 1.2% by weight of a 1: 1 mixed resin was mixed to obtain a positively chargeable two-component developer.

The particle size distribution and various characteristics of this toner are as shown in Table 1.

The prepared two-component developer was charged into a developing device shown in FIG. 1 of the accompanying drawings, and a development test was performed. The developing conditions will be described with reference to FIG.

The latent image holding member (drum) 1 rotates at a peripheral speed of 100 mm / sec in the direction of arrow a. Reference numeral 3 denotes a stainless steel sleeve having an outer diameter of 200 mm and a thickness of 0.8 mm, which rotates at a peripheral speed of 150 mm seconds in the direction of arrow b, and the surface of which is blasted with spherical glass beads.

On the other hand, a magnet 4 of a sintered ferrite type is fixed in the rotating sleeve 3, and the pole arrangement is such that the maximum value of the surface magnetic flux density is about 980 gauss as shown in FIG. Non-magnetic blade 5
A non-magnetic stainless steel having a thickness of 1.2 mm was used. The blade-sleeve spacing was 400 μm.

On the surface of the latent image holding member 1 facing the sleeve 3, a charge pattern of a dark part -600V and a bright part -150V was set as an electrostatic latent image, and the distance from the sleeve surface was set to 350m.

Then, the frequency 1800 is applied to the sleeve by the power supply 12.
A voltage of 1300 V and a center value of -200 V was applied at Hz, peak-to-peak value, and development was performed. The image formation test was continuously performed 5,000 times, and 5,000 toner images were generated. The results are shown in Table 2.

As is clear from Table 2, the two-component developer of the present invention has excellent image density in both the line portion and the large area portion of characters and the like, and also has excellent fine line reproducibility and resolution. After that, the original image quality was maintained. Also, the per copy cost was small and the economy was excellent.

The multi-segmentation classifier used in this embodiment and the classification process by the classifier will be described with reference to FIGS. 2 and 3. FIG. 2 and 3, the multi-segment classifier 21 has a side wall having a shape indicated by 22, 23, a lower wall has a shape indicated by 25, and a side wall 24 and a lower wall 25 have respective shapes. Equipped with knife edge type classification edges 26 and 27, this classification edge 2
According to 6,27, the classification zone is divided into three. Provided below the side wall 22 is a raw material supply nozzle 26 that opens into the classification chamber, and a Coanda block 29 that is bent downward in the direction of extension of the tangent at the bottom of the nozzle to draw a long elliptical arc is provided. The classification chamber upper lower part 30 is provided with a knife-edge type inlet edge 31 in the direction of the classification chamber lower part, and furthermore, the classification chamber upper part is provided with air inlet pipes 32 and 33 which open to the classification chamber. Further, first and second gas introduction adjusting means 34 and 35 such as dampers and static pressure gauges 3 are provided in the intake pipes 32 and 33, respectively.
6,37 are provided. Discharge pipes 38, 3 having discharge ports that open into the room on the bottom of the classification chamber
There are 9,40. The classified powder is introduced under reduced pressure from the supply nozzle 28 into the classification area, and the Coanda block is formed by the Coanda effect.
Due to the action of the co-and-effect of 29 and the action of the high-speed air flowing in at that time, it moves along a curved line 41, and coarse powder (discharge pipe 38), black fine powder having a predetermined volume average particle size and particle size distribution ( It was classified into discharge pipe 39) and ultrafine powder (discharge pipe 40).

Example 2 Instead of the toner used in Example 1, a toner having various properties as shown in Table 1 by controlling the pulverization and classification conditions was used, and a positively charged hydrophobic fumed silica (BET 200 m ² / g) was used. ) 0.8 parts, hydrophobic dry alumina (BET 100m
^{2 /} g) 0.2 part was externally added.

In the same manner as in Example 1, a two-component developer was prepared and evaluated.

As shown in Table 2, stable and clear high-quality images were obtained.

Example 3 The same method as in Example 1 was repeated except that the toner used in Example 1 was replaced with 4 parts of copper phthalocyanine as a colorant and 2 parts of quaternary ammonium salt instead of nigrosine.
A two-component developer was prepared and evaluated in the same manner as in Example 1 except that toners having various properties shown in the table were used.

As shown in Table 2, a stable, clear, high-quality blue image was obtained.

Example 4 To 100 parts of the black fine powder of Example 1, 1.0 part of positively charged hydrophobic dry silica and 0.3 part of polyvinylidene fluoride powder (average primary particle diameter 0.3 μm, average weight molecular weight 300,000) were added, and a Henschel mixer was added. And a two-component developer was obtained and evaluated in the same manner as in Example 1. As shown in Table 2, it was possible to obtain an image having better image density and image quality stability.

Example 5 Using the above materials, a black fine powder was obtained in the same manner as in Example 1. 0.9 parts of hydrophobic fine silica powder (BET specific surface area: 130 m ^{2 /} g) was added to 100 parts of the black fine powder and mixed with a Henschel mixer to prepare a negatively chargeable toner.

The particle size distribution and the like of this black fine powder were as shown in Table 1.

10 parts of this toner and vinylidene fluoride-tetrafluoroethylene copolymer (monomer polymerization weight ratio 80/20),
Styrene-2 ethylhexyl acrylate-methyl methacrylate copolymer (monomer polymerization weight ratio 45/20/35) 1:
90 parts of a ferrite carrier (volume average particle diameter 35 μm) coated with 0.5% by weight of the mixed resin 1 was mixed to obtain a two-component developer.

This two-component developer was applied to a copying machine equipped with an amorphous silicon photosensitive drum for forming a positively charged electrostatic image, and an image output test was performed on 5,000 sheets.

As shown in Table 2, stable and clear high-quality images were obtained.

Example 6 In Example 5, 4 parts of perylene scarlet was used as a coloring agent, and hydrophobic dry silica (BET 300m) was used as an inorganic compound fine powder.
^{2 /} g), and a two-component developer was prepared in the same manner as in Example 5 except that 0.2 part of hydrophobic dry titania (BET 100 m ^{2 /} g) was used, and the same evaluation was performed. The particle size distribution is shown in Table 1 and the evaluation results are shown in Table 2. As shown in Table 2, clear red images were obtained with the bank.

Comparative Example 1 Evaluation was performed in the same manner as in Example 1 except that toner having various characteristics shown in Table 1 by controlling the fine pulverization classification conditions was used instead of the toner used in Example 1. went. The results are shown in Table 2.

Although a good image was obtained in the initial stage, the density gradually decreased as copying continued, and the inside of the solid portion became slightly hollow. In addition, fogging began to be seen and gradually worsened.

Comparative Example 2 Evaluation was performed in the same manner as in Example 1 except that toner having various characteristics shown in Table 1 by controlling the fine pulverization classification conditions was used instead of the toner used in Example 1. went. Table 2 shows the results.

A good image was obtained in the initial stage, but when copying was repeated, a decrease in density was observed, the image began to be rough, and the reproducibility of fine lines was reduced.

Comparative Example 3 Evaluation was performed in the same manner as in Example 1 except that toner having various characteristics shown in Table 1 by controlling the fine pulverization classification conditions was used instead of the toner used in Example 1. went. Table 2 shows the results.

At the beginning, the image in the line portion was not a problem, but the solid portion was slightly hollow. When copying was repeated, fogging appeared, the hollow area became severe, and the density gradually decreased. Further, the development of the line portion was also deteriorated, and the reproducibility of fine lines and the resolution were reduced.

Comparative Example 4 Evaluation was performed in the same manner as in Example 1 except that the toner used in Example 1 was replaced with a toner having various characteristics shown in Table 1 by controlling the conditions of fine pulverization and classification. went. Table 2 shows the results.

Although there were no problems in density and image quality even after the initial 5000 sheets of image formation, the resolution and halftone reproduction were slightly inferior to those in Example 1.

[Effects of the Invention] Since the present invention is a two-component developer having a specific particle size distribution, it exhibits the following excellent effects.

(1) A two-component developer which is particularly excellent in resolution and fine line reproducibility and excellent in fine-grained halftone reproduction.

(2) A two-component developer having no change in performance when used repeatedly.

(3) A two-component developer that provides high image density with low consumption.

(4) A two-component developer capable of forming a toner image having excellent resolution, gradation, and fine line reproducibility even in an image forming apparatus using a digital image signal.

[Brief description of the drawings]

In the accompanying drawings, FIG. 1 shows a schematic sectional view of a developing device used for image output in Examples and Comparative Examples, and FIG.
FIG. 3 is a schematic sectional perspective view of the multi-segment classification means. DESCRIPTION OF SYMBOLS 1 ... Latent image holding member, 2 ... Developer supply container 3 ... Non-magnetic sleeve, 4 ... Fixed magnet 5 ... Non-magnetic blade 6 ... Magnetic particle circulation area limiting member 7 ... Magnetic particles, 8 ... ... Non-magnetic toner 9... Developer collecting container part 10... Anti-scattering member 11... Magnetic member 12... Bias power supply 13. … Side wall, 25 …… bottom wall 26,27 …… classification edge, 28 …… material supply nozzle 29 …… Coanda block, 30 …… upper wall 31 …… intake edge, 32,33 …… intake pipe 34 …… First gas introduction adjusting means 35 Second gas introduction adjusting means 36, 37 Static pressure gauge 38 Discharge pipe (coarse powder) 39 Discharge pipe (fine powder having predetermined particle size and particle size distribution) 40 …… Discharge pipe (ultra fine powder), 41 …… Curved line

Claims (1)

(57) [Claims] 1. A two-component developer having a carrier coated with a toner and a resin, containing 60.0% by number or more of toner particles having a particle size of 5 μm or less, and having a coefficient of variation (volume distribution) of the volume distribution of the toner. Standard deviation / volume average particle size)
22.5 to 26.0, and the volume average particle diameter of the toner is 4.00 to 6.
A two-component developer, wherein a fine particle of an inorganic compound as a fluidity imparting agent is externally added to the toner, and the carrier has a volume average particle diameter of 10 to 80 μm.