JPH1173005A - Image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a image forming device and an image forming method which is compact and capable of obtaining a high quality image for a long period of time by reducing the change in the bulk density of a developer for carrying out accurate toner concentration control. SOLUTION: In an image forming method comprising a charging process, a latent image forming process, developing process, and a toner concentration control process for controlling the toner concentration by detecting the change in magnetic permeability of a two-component base developer by utilizing the inductance of a coil; the two-component developer 19 to be used is made to have a spherical magnetic particle dispersion type carrier 19b and nonmagnetic toner 19a in which an external additive agent is attached to the surfaces of the nonmagnetic toner particles. The external additive agent that is existent as a primary particle or secondary particle in the toner particle is provided with an inorganic oxide particulate (A) whose shape factor SF-1 is 100 to 130, and with an aspherical inorganic oxide particulate (B) which is produced by composing a plurality of particles and whose shape factor SF-1 is greater than 150.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and an image forming apparatus used for developing an electric latent image or a magnetic latent image in an electrophotographic method or an electrostatic printing method. The present invention relates to an image forming method and an image forming apparatus that improve the life of a developer and have a stable image density.

[0002]

2. Description of the Related Art Conventionally, a dry developer as a developer is carried on the surface of a developer carrier, and the developer is transported and supplied to the vicinity of the surface of the latent image carrier carrying an electrostatic latent image. It is well known that an electrostatic latent image is developed and visualized while an alternating (alternating) electric field is applied between the latent image carrier and the developer carrier.

Since the developer carrier generally uses a developing sleeve in many cases, it is referred to as a "developing sleeve" in the following description, and the latent image carrier generally uses a photosensitive drum. Since there are many, they are referred to as “photosensitive drums” in the following description.

As the above-mentioned developing method, a magnetic brush is conventionally formed on the surface of a developing sleeve in which a magnet is disposed by using a two-component developer composed of, for example, magnetic carrier particles and non-magnetic toner particles. The magnetic brush is rubbed or brought close to the photosensitive drum facing and holding, and the developing sleeve and the photosensitive drum (between SD)
A so-called magnetic brush developing method is known in which a toner particle is repeatedly subjected to transfer and reverse transfer by repeatedly applying an alternating electric field to the developing sleeve from the developing sleeve side and back to the photosensitive drum side, thereby performing development. See JP-A-55-32060 and JP-A-59-165082.

In the two-component magnetic brush developing method,
The amount of toner corresponding to the toner consumed by development is
By being replenished, the mixing ratio of the toner particles and the magnetic carrier (hereinafter, T / C ratio) is kept constant. At this time, various methods have been proposed for detecting the T / C ratio in the developing container. For example, a detecting means is provided around the photosensitive drum, and light is applied to the toner transferred from the developing sleeve side to the photosensitive drum side, and the transmitted light and reflected light at this time are T / C.
In a developing container, a detecting means is provided on a developing sleeve, and a T / C ratio is detected from reflected light when light is applied to a developer applied on the developing sleeve; A method of detecting a change in the magnetic permeability (μ) of the developer in a certain volume near the sensor using the inductance of the coil and detecting the T / C ratio has been proposed and put into practical use. I have.

However, the method of detecting the T / C ratio from the amount of toner on the photosensitive drum has a problem that it is not possible to secure a space for installing the detecting means with the downsizing of a copying machine or an image forming apparatus. In the method of detecting the T / C ratio from the reflected light when the developer applied on the developing sleeve is irradiated with light, the T / C ratio can be accurately determined if the detecting means becomes dirty due to scattering of toner. There is a problem that cannot be detected. On the other hand, a method of detecting the T / C ratio by detecting the change in the apparent magnetic permeability μ of the developer in a certain volume near the sensor by using the inductance of the coil (hereinafter referred to as a toner concentration detection sensor) In addition to the fact that the cost of the sensor alone is inexpensive, because it is not affected by the above-mentioned space problem and the problem of dirt due to toner scattering, in a low-cost, small-space copier or image forming apparatus,
It can be said that this is an optimal T / C ratio detecting means.

The above-described toner concentration detection sensor utilizing the change in the magnetic permeability of the developer means that, for example, when the magnetic permeability increases, the T / C in the developer decreases within a certain volume. Since the toner replenishment is started because it means that the amount of toner in the developer has been reduced. Conversely, when the magnetic permeability has decreased, it means that the T / C ratio in the developer has increased within a certain volume. Therefore, this means that the amount of toner in the developer has increased, so that the T / C ratio is controlled based on a sequence in which toner supply is stopped.

[0008]

However, a toner density detection sensor of the type that detects a change in the magnetic permeability (μ) of a developer in a certain volume as described above has a problem that the bulk density of the developer itself is affected by some influence. If it has changed, the magnetic permeability of the developer will change with the change in bulk density,
There is a problem that the sensor output also changes according to the change in magnetic permeability. That is, although the T / C ratio in the developing container is constant, the change in the bulk density in the developing container means that the amount of the developer (carrier) in a certain volume near the toner concentration detection sensor changes. The change in the magnetic permeability will appear in the sensor output. As a result, a sensor output indicating that the toner has been consumed is output without consuming the toner, and the toner is replenished, or the toner is not reduced despite the toner amount being reduced. There is a problem that the sensor output is output and toner is not supplied. In the former case, there is a problem that the image density is increased due to excessive toner replenishment, a problem that the amount of the developer increases due to an increase in the amount of the toner and the developer overflows from the developing container, or an increase in the toner ratio in the developer. This causes a problem such as toner scattering due to a decrease in toner charge amount. On the other hand, in the latter case, problems such as image deterioration due to a decrease in the amount of toner in the developer, low image density, and low image density due to an increase in toner charge amount are caused.

The cause of the above-mentioned problem is that, in the developing apparatus and the developer system used in the above-mentioned developing system, as a result of detailed examination of the present invention, it is mainly caused by the following three phenomena. Do you get it.

[0010] The first phenomenon is caused by the conventionally used pulverized toner. The pulverized toner is in a stationary state, a flowing state, or a standing state because the individual toner shapes are uneven and different from each other. In addition, the bulk density of the developer tends to fluctuate, and the fluctuation of the toner shape due to the durability causes a large fluctuating bulk density.

The second phenomenon is caused by a structure in which the developer is stored near the regulating blade of the developing sleeve and the developer is compressed in order to prevent the uneven coating of the developer on the developing sleeve. With this configuration, the developer is gradually and mechanically and magnetically compressed, and as a result, a change in the bulk density of the developer due to a change in the shape of the toner or a change in the bulk density due to the embedding of the external additive is caused. This causes a change in magnetic permeability and the like.

The third phenomenon is a problem relating to the fluctuation of the toner charge amount during the rotation of the developing sleeve. As described above, because the developer is clogged in the developer reservoir near the regulating blade of the developing sleeve and the developer is easily compressed, the frictional force between the agents due to the rotation of the developing sleeve also increases, and if the developing sleeve rotates. The more the external additive is transferred to the carrier, the larger the change in the toner charge amount. A large change in the toner charge amount indicates a large change in the repulsive force between the developers. The repulsive force between the developers tends to repel as the toner charge amount increases, and the repulsion spreads between the developers, so that the bulk density of the developer decreases. Therefore, the fluctuation of the toner charge amount is large and the fluctuation of the bulk density of the developer is large.

Since the bulk density of the developer greatly changes due to the above three phenomena, it has been difficult to make full use of a toner density detection sensor utilizing a change in magnetic permeability in a conventional developing device and developer configuration.

[0014]

SUMMARY OF THE INVENTION The present invention provides a charging step for charging a latent image carrier; a latent image forming step for forming an electrostatic latent image on the charged latent image carrier; An electrostatic latent image is formed by a developing unit having a developer carrier that carries and transports a two-component developer in opposition to the image carrier, and a magnetic field generator fixedly provided inside the developer carrier. A developing step of developing an image; a step of controlling the toner concentration by detecting a change in the magnetic permeability of the two-component developer using the inductance of the coil; A spherical magnetic powder-dispersed carrier in which at least a magnetic powder is dispersed in a binder resin; and a nonmagnetic toner having an external additive attached to the surface of nonmagnetic toner particles. The mold carrier has a weight average particle size of 1
5 to 60 μm, the non-magnetic toner particles have a weight average particle diameter of 2 to 9 μm, and the external additive is present as primary particles or secondary particles on the toner particles. Is 100 to 130, and non-spherical inorganic oxide fine particles (B) having a shape factor SF-1 of more than 150, which are generated by combining a plurality of particles. And an image forming method.

The present invention relates to a latent image carrier for carrying an electrostatic latent image; a charging means for charging the latent image carrier; and an electrostatic latent image on the charged latent image carrier. A latent image forming means for forming; a developer carrier for carrying and transporting a two-component developer opposed to the latent image carrier for developing the electrostatic latent image; and the developer carrier. Developing means having a magnetic field generator fixedly provided inside the toner; toner concentration controlling means for controlling toner concentration by detecting a change in the magnetic permeability of the two-component developer using the inductance of the coil;
In the image forming apparatus having, the two-component developer,
A spherical magnetic powder-dispersed carrier in which at least magnetic powder is dispersed in a binder resin; and a non-magnetic toner in which an external additive is attached to the surface of non-magnetic toner particles. The carrier has a weight average particle size of 15 to 60 μm, and the nonmagnetic toner particles have a weight average particle size of 2 to 9 μm.
Wherein the external additive is present as primary particles or secondary particles on the toner particles, and has a shape factor SF-1 of 100
And inorganic oxide fine particles (A) having a shape factor SF-1 of 15
And a non-spherical inorganic oxide fine particle (B) larger than 0.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a developer comprising a magnetic powder-dispersed carrier and a non-magnetic toner having two kinds of external additives having different shapes adhered to the surface is used. The change in bulk density is reduced, and the stability of toner density control is improved. Further, in the present invention, particularly when a spherical magnetic powder-dispersed carrier produced by a polymerization method is used, the change in bulk density of the developer is reduced without changing the fluidity of the carrier over a long period of time. In addition, the stability of toner density control can be improved.

As the toner used in the present invention, any of toner particles produced by a pulverization method or a polymerization method can be used, but toner particles produced by a polymerization method, particularly a suspension polymerization method, are preferably used. Can be Also,
After allowing the monomer to further adsorb to the polymer particles once obtained,
A seed polymerization method in which polymerization is performed using a polymerization initiator can also be suitably used in the present invention.

In the production of toner particles by a pulverization method, components such as a binder resin, a colorant, and a charge control agent are sufficiently mixed by a ball mill or other mixer, and then mixed with a heat kneader such as a hot roll kneader or an extruder. After kneading well, solidifying by cooling, and then mechanically pulverized and classified to obtain toner particles. Further, after classification, toner particles subjected to a hot air treatment or a spheroidization treatment by applying a mechanical impact are more preferable.

Examples of the type of the binder resin used in the production of the toner particles by the pulverization method include, for example, styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene and a homopolymer of a substituted product thereof; styrene-p
-Chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer Polymer, 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-based copolymers such as styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester Fat, polyurethane, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resin, coumarone-indene resin, petroleum resin. Further, a crosslinked styrene resin is also a preferable binder resin.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Double such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide A monocarboxylic acid having a bond or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, or dimethyl maleate and a substituted product thereof; for example, vinyl chloride, vinyl acetate, Vinyl esters such as vinyl benzoate, for example, ethylene olefins such as ethylene, propylene, butylene; for example, vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; for example, vinyl methyl ether Vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether is used alone or in combination, as the case with a crosslinking agent, compounds are used mainly having two or more polymerizable double bonds. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinyl Divinyl compounds such as aniline, divinyl ether, divinyl sulfide, divinyl sulfone; and 3
Compounds having at least two vinyl groups can be used alone or as a mixture. In particular, it is preferable to add a polar resin such as a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, and a saturated polyester resin.

The toner particles produced by the polymerization method are as follows:
Since the particle size distribution is sharper than the pulverized toner particles and the shape is close to a true sphere, there is little change in shape due to durability,
The change in bulk density is also small. In the case of pulverized toner, the uneven surface is scraped off due to friction caused by the carrier or toner contact due to agitation and approaches a spherical shape. Because the shape change is small,
Little change in bulk density.

When a polymerization method is used for the production of toner particles, the toner particles can be produced specifically by the following production method. Monomer obtained by adding a release agent, colorant, charge control agent, polymerization initiator, and other additives consisting of a low softening point substance to a monomer, and then dissolving or dispersing it uniformly using a homogenizer, ultrasonic disperser, etc. The composition is dispersed in an aqueous phase containing a dispersant using a conventional stirrer, homomixer, homogenizer, or the like. Preferably, the stirring speed and time are adjusted so that the droplets of the monomer composition have the desired size of the toner particles, and granulation is performed. Thereafter, stirring may be performed by the action of the dispersant to such an extent that the particle state is maintained and the sedimentation of the particles is prevented. The polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to improve durability characteristics in the image forming method of the present invention, in order to remove unreacted polymerizable monomers and by-products, the second half of the reaction, Alternatively, a part of the aqueous medium may be distilled off after the completion of the reaction. After the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization method, water 3 is usually added to 100 parts by weight of the monomer system.
It is preferable to use 00 to 3000 parts by weight as the dispersion medium.

In the present invention, a toner having a core / shell structure in which a material having a low softening point is coated with a shell resin is preferably used. The function of the core / shell structure is that the anti-blocking property can be imparted without deteriorating the excellent fixability of the toner, and the polymerization of only the shell portion is more effective than the polymerization of a bulk toner having no core. This is because the residual monomer can be easily removed in the post-treatment step after the step.

A toner having a core / shell structure can be obtained by setting the polarity of a material in an aqueous medium to be smaller for a low softening point substance than for a main monomer.

As the main component of the core portion, a substance having a low softening point is preferable, and a compound having a main maximum peak value of 40 to 90 ° C. measured according to ASTM D3418-8 is preferable. When the maximum peak is less than 40 ° C., the self-cohesive force of the low softening point substance becomes weak, and as a result, the hot offset resistance becomes weak, which is not preferable. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature increases, which is not preferable. Further, in the case of obtaining a toner by a direct polymerization method, since the temperature of the maximum peak value is high because the granulation and polymerization are performed in an aqueous system, a substance having a low softening point mainly precipitates during the granulation and hinders the suspension system. Not preferred.

In the measurement of the temperature of the maximum peak value of the present invention,
For example, DSC-7 manufactured by Perkin Elemer Inc. is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of the calorific value uses the indium heat of fusion. An aluminum pan was used as a sample, an empty pan was set as a control, and the temperature was raised at a rate of 10 ° C./min. Was measured.

Specifically, paraffin wax, microcrystalline wax, polyolefin wax, Fischer-Tropsch wax, carnauba wax, amide wax, alcohol, higher fatty acid, acid amide wax, ester wax, ketone, hydrogenated castor oil, plant system, Animal, mineral, petrolactam and their derivatives or their graft / block compounds can be used.

The low softening point substance is 5% based on toner particles.
It is preferable to add 30% by weight. If the addition is less than 5% by weight, it takes a burden to remove the above-mentioned residual monomer. If the addition exceeds 30% by weight, toner particles are likely to coalesce during granulation even in production by a polymerization method. Those having a wide distribution were easily formed, and were not suitable for the present invention.

As the outer shell resin forming the shell portion, generally used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers are preferable. The following monomers are preferably used as a monomer for obtaining a styrene-based copolymer. Styrene-based monomers such as styrene, o- (m-, p-)-methylstyrene, m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid Propyl, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate,
Behenyl (meth) acrylate, 2- (meth) acrylate
(Meth) acrylate monomers such as ethylhexyl, dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide A dimer is preferably used. These can be used alone or generally in the published Polymer Handbook, 2nd edition III-P 139-192 (J
ohn Wiley & Sons), and the monomers are appropriately mixed and used so that the theoretical glass transition temperature (Tg) thereof is 40 to 75 ° C. If the theoretical glass transition temperature is lower than 40 ° C., problems arise in terms of the storage stability of the toner and the durability stability of the developer. In such a case, the color mixture of the toners of each color is insufficient, resulting in poor color reproducibility, and furthermore, the transparency of the OHP image is significantly reduced, which is not preferable from the viewpoint of high image quality. The molecular weight of the shell resin is G
It is measured by PC (gel permeation chromatography). As a specific GPC measurement method, a toner was previously prepared using a Soxhlet extractor with a toluene solvent.
After extraction for 0 hour, toluene is distilled off using a rotary evaporator, and furthermore, an organic solvent such as chloroform, which does not dissolve the shell resin in which the low softening point substance is soluble, is sufficiently washed, and THF (tetrahydrofuran) is added. )
A solution obtained by filtering a solution dissolved in water through a solvent-resistant membrane filter having a pore diameter of 0.3 μm was used for the sample, and the column configuration was A-801, manufactured by Showa Denko KK
802, 803, 804, 805, 806 and 807 can be connected to measure the molecular weight distribution using a standard polystyrene resin calibration curve. Number average molecular weight (Mn) of the obtained resin component
Is 5000 to 1,000,000, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn)
Is preferably 2 to 100 for the present invention.

In the present invention, when a toner having a core / shell structure is produced, it is particularly preferable that a polar resin is further added in addition to the outer shell resin in order to incorporate a low softening point substance into the outer shell resin. . As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with a shell resin or a monomer in the molecule. If a polar resin having an unsaturated group is included, a cross-linking reaction occurs with the monomer forming the outer shell resin layer. It is disadvantageous and not preferred.

In the present invention, an outermost resin layer may be further provided on the surface of the toner particles.

The glass transition temperature of the outermost resin layer is designed to be equal to or higher than the glass transition temperature of the outer resin layer in order to further improve the blocking resistance, and the outermost resin layer is crosslinked so as not to impair the fixability. Is preferred. The outermost resin layer preferably contains a polar resin and a charge control agent for improving the chargeability.

The method for providing the outermost shell layer is not particularly limited, but examples thereof include the following.

In the second half or after the end of the polymerization reaction, if necessary, a monomer in which a polar resin, a charge controlling agent, a cross-linking agent, etc. are dissolved and dispersed is added to the reaction system, the mixture is adsorbed on polymer particles, and a polymerization initiator is added. To conduct polymerization.

If necessary, a polar resin, a charge control agent,
A method in which emulsion polymerization particles or soap-free polymerization particles composed of a monomer containing a crosslinking agent or the like are added to a reaction system, and are aggregated on the surface of the polymerization particles and, if necessary, fixed by heat or the like.

If necessary, a polar resin, a charge control agent,
A method in which emulsion-polymerized particles or soap-free polymerized particles comprising a monomer containing a crosslinking agent or the like are mechanically fixed to the surface of toner particles in a dry manner.

The toner used in the present invention has a core /
The presence of the shell structure can be confirmed by the following method. After sufficiently dispersing the toner in a cold-setting epoxy resin, the cured product was cured for 2 days in an atmosphere at a temperature of 40 ° C., and the cured product was dyed using ruthenium tetroxide and, if necessary, osmium tetroxide in combination. Thereafter, a flaky sample was cut out using a microtome provided with diamond teeth, and the tomographic morphology of the toner was observed using a transmission electron microscope (TEM). In the present invention, it is preferable to use a ruthenium tetroxide staining method in order to give a contrast between the materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell. .

As a specific method for encapsulating the low softening point substance, the polarity of the material in the aqueous medium is set to be lower for the low softening point substance than for the main monomer, and a small amount of a large polar resin or By adding a monomer, a toner having a core / shell structure can be obtained.

The particle size distribution and the particle size of the toner particles can be controlled by changing the type and amount of a poorly water-soluble inorganic salt or a dispersing agent acting as a protective colloid, or by mechanical device conditions such as the rotor peripheral speed and the number of passes. A toner having a desired particle size can be obtained by controlling the stirring conditions such as the shape of the stirring blade, the shape of the container, and the concentration of the solid content in the aqueous solution.

Examples of the binder resin for toner used for pressure fixing include low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, higher fatty acid, and polyamide. Resins and polyester resins. These are preferably used alone or as a mixture. In particular, in the present invention, when a polymerization method is used as a method for producing toner particles, it is preferable that the method does not have polymerization inhibition and has no solubilized substance in an aqueous system.

In the present invention, in order to faithfully develop finer latent image dots for higher image quality, the yellow, magenta, cyan and black toner particles have a weight average particle diameter of 2 to 9 μm and have higher image quality. 3 to prevent fog and scattering
It is preferably about 9 μm. 2 μm weight average particle size
In toner particles having a particle size of less than 1, toner remaining on the photoreceptor due to a decrease in transfer efficiency is large, and further, it is likely to cause non-uniform unevenness of an image due to fog or poor transfer. Therefore, the toner used in the present invention is preferable. Absent. If the weight average particle size of the toner particles exceeds 9 μm, characters and line images are liable to be scattered.

In the present invention, the toner particles have a shape factor SF-1 of 100 to 140 and a shape factor SF-2 of 100.
Preferably it is ~ 120.

When the shape factor SF-1 exceeds 140, the toner particles deviate from a spherical shape, or when SF-2 is 12
If it exceeds 0, the irregularities on the surface of the toner particles become remarkable. The toner particles having a non-spherical shape or having irregularities on the surface are scraped off by friction due to contact between the carrier or the toner particles due to agitation and gradually become closer to a spherical shape. In a toner particle having a shape factor SF-1 of more than 140 or SF-2 of more than 120, a shape change is large.
The change in the bulk density is large, and the toner density detection sensor that measures the change in the magnetic permeability of the developer using the inductance of the coil tends to output an inappropriate output.

The charge control agents used in the present invention include:
Although a known toner can be used, in the case of a color toner, a charge control agent which is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is particularly preferable. Further, in the case where a direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibitory property and having no soluble substance in an aqueous system is particularly preferable. Specific examples of negative compounds include metal compounds of salicylic acid, naphthoic acid, and dicarboxylic acid, sulfonic acids, high molecular compounds having carboxylic acids as side chains, boron compounds, urea compounds, silicon compounds, calixarenes, and the like. Available, quaternary ammonium salt as positive system,
A polymer compound having the quaternary ammonium salt in a side chain,
Guanidine compounds, imidazole compounds and the like are preferably used.

The charge control agents described above are preferably used in the form of fine particles. In this case, the number average particle size of these charge control agents is preferably 2 μm or less, more preferably 1 μm or less.

The charge control agent is preferably used in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the resin. However, in the present invention, the addition of a charge control agent is not essential, and in the case where a two-component developing method is used, even when a non-magnetic one-component blade coating developing method is used utilizing frictional charging with a carrier. It is not always necessary to include a charge control agent in the toner by positively utilizing the triboelectric charging with the blade member and the sleeve member.

When the polymerization method is used in the present invention, for example, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo polymerization initiators such as nitrile and azobisisobutyronitrile; and peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide. Used. The amount of the polymerization initiator varies depending on the desired degree of polymerization, but is generally used in an amount of 0.5 to 20% by weight based on the monomer. The type of the initiator slightly varies depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.

To control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like can be further added and used.

As the dispersant, for example, inorganic oxides such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, Examples thereof include calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, a magnetic substance, and ferrite. Examples of organic compounds include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose,
Ethyl cellulose, sodium salt of carboxymethyl cellulose and starch are used by being dispersed in an aqueous phase. These dispersants are used in an amount of 0.1 to 100 parts by weight of the polymerizable monomer.
It is preferred to use 2 to 10.0 parts by weight.

As these dispersants, commercially available ones may be used as they are, but in order to obtain finely dispersed particles having a uniform particle size, the inorganic compound is formed under high-speed stirring in a dispersion medium. Can also. For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring. Further, 0.001 to 0.1 parts by weight of a surfactant may be used in combination for making these dispersants finer. Specifically, commercially available nonionic, anionic, and 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 and calcium oleate are preferably used.

As the colorant used in the present invention, a black colorant prepared by using carbon black, a magnetic substance, and a yellow / magenta / cyan colorant shown below as a black colorant is used.

The yellow colorant includes 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, 6
2, 74, 83, 93, 94, 95, 97, 109, 1
10, 111, 120, 127, 128, 129, 14
7, 168, 174, 176, 180, 181, 191
Is preferably used.

Examples of the magenta colorant 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 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan coloring agent, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15; 1, 15; 2, 1
5; 3, 15; 4, 60, 62, 66 can be particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by weight based on 100 parts by weight of the resin.

The external additives of the toner usable in the present invention include oxides such as alumina, titanium oxide, silica, zirconium oxide and magnesium oxide, as well as silicon carbide, silicon nitride, boron nitride and aluminum nitride. , Magnesium carbonate, and organosilicon compounds.

Among these, as the inorganic oxide fine particles (A), alumina, titanium oxide, zirconium oxide, magnesium oxide or silica-treated fine particles thereof are used to stabilize the charging of the toner regardless of temperature and humidity. Further, alumina or titanium oxide fine particles or silica surface-treated fine particles thereof are preferable for improving the fluidity of the toner.

The production method is not particularly limited, and a method of oxidizing a halide or an alkoxide in a gas phase or a method of producing while hydrolyzing in the presence of water can be used. Is preferably low-temperature baking that does not cause coagulation.

In the present invention, amorphous titanium oxide or anatase-type titanium oxide, rutile-type titanium oxide and amorphous alumina or amorphous alumina or γ which are calcined at a low temperature, in particular, are spherical and easy to monodisperse into primary particles.
Type alumina is preferred.

Furthermore, the inorganic oxide fine particles (A) are preferably subjected to a hydrophobic treatment in order to reduce the dependence of the charge amount of the toner on the environment such as temperature and humidity and to prevent the toner from being released from the toner surface. Good for Examples of the hydrophobizing agent include coupling agents such as silane coupling agents, titanium coupling agents, and aluminum coupling agents, and oils such as silicone oils, fluorine-based oils, and various modified oils.

Among the above-mentioned hydrophobizing agents, the coupling agent, in particular, reacts with the residual groups on the inorganic oxide fine particles or the adsorbed water to achieve a uniform treatment, thereby stabilizing the charge of the toner and imparting fluidity. Is preferred.

Therefore, as the inorganic oxide fine particles (A) used in the present invention, alumina or titanium oxide fine particles that have been surface-treated while hydrolyzing a silane coupling agent are preferably used for stabilization of charge and fluidity. This is extremely effective in providing the following.

The inorganic oxide fine particles (A) subjected to the above hydrophobic treatment preferably have a hydrophobicity of 20 to 80%, more preferably 40 to 80%.

The inorganic oxide fine particles (A) have a hydrophobicity of 20
%, The amount of charge is greatly reduced due to long-term storage under high humidity, and a mechanism for promoting charge on the hardware side is required.
If the degree of hydrophobicity exceeds 80%, it becomes difficult to control the charging of the inorganic fine powder itself, and as a result, the toner tends to charge up under low humidity.

The inorganic oxide fine particles (A) used in the present invention preferably have a BET specific surface area of 60 to 230 m ² / g, more preferably 70 to 180 m ² / g. BET specific surface area is 60 ~ 230m
If it is ² / g, the chargeability and fluidity of the toner will be good, and high image quality and high density image formation will be achieved. If the BET specific surface area is less than 60 m ² / g, the chargeability of the toner will decrease. When the BET specific surface area is greater than 230 m ² / g, the chargeability of the toner becomes unstable, especially when left under high humidity for a long time, and problems such as toner scattering tend to occur. Become.

The inorganic oxide fine particles (A) exist as primary particles or secondary particles on the surface of the toner particles, and the average particle diameter on the surface of the toner particles is 10 to 400.
m μm, preferably 15 to 200 m μm, and more preferably 15 to 200 μm.
The thickness of 100 mμm is preferable in terms of imparting fluidity of the toner and preventing separation from the toner surface during durability.

The average particle diameter of the inorganic oxide fine particles (A) is 1
If it is less than 0 μm, even when combined with non-spherical particles, the toner particles are likely to be embedded on the surface of the toner particles, causing toner deterioration, and the stability of toner concentration control is likely to be reduced.

The average particle diameter of the inorganic oxide fine particles (A) is 4
If it exceeds 00 μm, it is difficult to obtain sufficient fluidity of the toner, the toner tends to be non-uniform, and as a result, toner scattering and fogging are likely to occur.

The ratio of the major axis to the minor axis of the inorganic oxide fine particles (A) is preferably 1.5 or less, more preferably 1.3 or less. When the ratio of the major axis to the minor axis is 1.5 or less, the dispersion on the surface of the toner particles is uniform, and the fluidity of the toner can be favorably maintained over a long period of time.
When the ratio of the major axis to the minor axis is larger than 1.5, the dispersion on the surface of the toner particles tends to be uneven, and the toner particles are easily separated from the surface of the toner particles particularly when left under high humidity. Problems such as scattering are more likely to occur.

Shape factor SF− of inorganic oxide fine particles (A)
1 is preferably from 100 to 130, more preferably from 100 to 125, for imparting fluidity to the toner.
If the SF-1 of the inorganic oxide fine particles (A) exceeds 130, the dispersion on the toner surface tends to be non-uniform, and problems tend to occur. The inorganic oxide fine particles (A) subjected to the hydrophobic treatment preferably have a light transmittance of 40% or more at a wavelength of 400 μm.

That is, even if the inorganic oxide fine particles (A) used in the present invention have a small primary particle diameter,
When actually contained in the toner, the particles are not necessarily dispersed in the form of primary particles, but may form secondary particles. Therefore, no matter how small the primary particle diameter is, the effect of the present invention is reduced if the effective diameter acting as the secondary particles is large. However, the higher the light transmittance at the lower limit wavelength of 400 m μm in the visible region, the smaller the secondary particle size, the better the results in terms of the fluidity-imparting ability and the sharpness of the projected image of the OHP in the case of color toner. Can be expected. The reason for selecting 400 mμm is the boundary region between ultraviolet and visible light, and it is said that those having a particle size of 以下 or less of the light wavelength are transmitted. Without.

By subjecting the coupling agent to hydrolysis and surface treatment while mechanically dispersing the inorganic oxide fine particles to have a primary particle size in the presence of water, coalescence of the particles hardly occurs. As a result, the inorganic oxide fine particles are surface-treated in a state of substantially primary particles, and inorganic oxide fine particles having a light transmittance of 40% or more at a wavelength of 400 μm are obtained.

When treating the surface of the inorganic oxide fine particles while hydrolyzing the coupling agent in the presence of water,
Since a mechanical force is applied to disperse the fine particles into the primary particles, there is no need to use a coupling agent that generates a gas such as chlorosilanes or silazanes, and further, the particles are combined. A high-viscosity coupling agent or silicone oil, which could not be used for this purpose, can be used together, and the effect of hydrophobization is enormous.

The coupling agent may be any of a silane coupling agent and a titanium coupling agent. Particularly preferably used is a silane coupling agent, the following general formula S _m SiY _n R: an alkoxy group m: 1 to 3 integer Y: alkyl group vinyl group, glycidoxy group, a hydrocarbon group containing a methacrylic group n: Represented by an integer of 1 to 3, for example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrisilane. Methoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, etc. That.

[0075] More _{preferably, C a H 2a + 1 -Si} (OC b H 2b + 1) 3 a = 4~12, a b = 1 to 3.

Here, when a in the general formula is smaller than 4, the treatment becomes easy, but sufficient hydrophobicity cannot be achieved.
If a is larger than 12, the hydrophobicity is sufficient, but the coalescence of the particles increases, and the fluidity-imparting ability decreases.

If b is larger than 3, the reactivity is lowered and the hydrophobicity is not sufficiently achieved. Therefore, a in the above general formula is 4 to 12, preferably 4 to 8, and b is 1
-3, preferably 1-2.

The processing amount is 1 to 5 with respect to 100 parts by weight.
0 parts by weight, preferably 3 to 40 parts by weight to uniformly treat the particles without coalescing, the degree of hydrophobicity is 20 to 98%,
Preferably 30-90%, more preferably 40-80%
You can do it.

As the non-spherical inorganic oxide fine particles (B) produced by coalescing a plurality of particles, known ones are used. However, in order to improve charge stability, developability, fluidity, and storage stability, It is preferable to be selected from silica, alumina, titanium oxide or a double oxide thereof. Among them, silica is particularly preferable because the coalescence of primary particles can be controlled to some extent arbitrarily depending on oxidation conditions such as a starting material and temperature. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide and an alkoxide or a so-called wet silica produced from an alkoxide, a water glass and the like, and a dry silica called a fumed silica can be used. There is
Dry silica having less silanol groups on the surface and inside the silica fine powder and having less production residues such as Na ₂ O and SO ₃ ²⁻ is preferred. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the manufacturing process. Is also included.

The non-spherical inorganic oxide fine particles (B) are BET
The specific surface area is preferably ²⁰ to 90 m ² / g,
Furthermore, 25-80 m < ² > / g is more preferable. When the BET specific surface area is 20 to 90 m ² / g, the toner is easily dispersed uniformly on the surface of the toner particles, and at the time of development, plays a role as a spacer between the latent image carrier and the toner particles, thereby improving transferability. . When the BET specific surface area is less than 20 m ² / g, the toner is easily released from the toner particles on the latent image carrier, and the latent image carrier is easily scraped or damaged. BET
When the specific surface area is larger than 90 m ² / g, the function as a spacer on the latent image carrier is weak, and the transferability tends to decrease particularly under low humidity.

Further, the shape of the non-spherical inorganic oxide fine particles (B) is not a simple one in which a plurality of particles are united in a rod shape or a block shape, but a shape in which a plurality of particles are united in a shape having a bent portion. This can prevent the inorganic oxide fine particles (A) from being buried in the toner surface, and at the same time, prevent the developer from being closest packed, thereby suppressing a change in the bulk density of the developer. More preferred. FIG. 6 shows a schematic diagram of the particle shape of the non-spherical inorganic oxide fine particles (B).

The term “non-spherical” as used herein means the shape factor SF-1
Is greater than 150, preferably SF-1
Is particularly preferably 190 or more, more preferably 200 or more. SF-1 of the non-spherical inorganic oxide fine particles (B) is 15
When it is larger than 0, the degree of irregularity is high and the toner particles do not move much on the toner particles, so that the function as a spacer can be maintained. If the SF-1 of the non-spherical inorganic oxide fine particles (B) is 150 or less, the bulk density of the developer tends to be small, especially when a pattern with a small image ratio is continuously printed, and the toner concentration is reduced. Tends to cause a reduction in image density.

The average particle size of the non-spherical inorganic oxide fine particles (B) is preferably larger than that of the inorganic oxide fine particles (A), and more preferably 20 m μm or more, particularly 40 m μm or more, so that the burial on the surface of the toner particles is prevented. It is preferable in terms of suppression. The average particle diameter of the non-spherical inorganic oxide fine particles (B) is preferably from 120 to 600 m.
More preferably, it is 0 to 500 mμm. The average particle size of the non-spherical inorganic oxide fine particles (B) is 120 to 600 m
When the thickness is μm, the effect as a spacer for suppressing the embedding of the inorganic oxide fine particles (A) into the surface of the toner particles can be sufficiently achieved. When the average particle size of the non-spherical inorganic oxide fine particles (B) is less than 120 mμm, the above-mentioned spacer effect is small, and as a result, the change in the bulk density of the developer becomes large and the change in the toner density becomes large. Cheap. The average particle diameter of the non-spherical inorganic oxide fine particles (B) is 60
When the thickness is larger than 0 μm, the spacer effect can be expected, but it is easily released from the surface of the toner particles, and the latent image carrier is easily scraped or damaged.

Further, the non-spherical inorganic oxide fine particles (B)
The ratio of the major axis to the minor axis is preferably 1.7 or more, more preferably 2.0 or more, and particularly preferably 3.0 or more. When the ratio of the major axis to the minor axis is 1.7 or more, it is difficult to be embedded in the surface of the toner particles, and the above-described spacer effect is exerted for a long time. The ratio of major axis to minor axis is 1.7
If it is less than 3, when printing a pattern with a small image ratio, the function as a spacer is likely to decrease.

Such non-spherical inorganic oxide fine particles are preferably produced by the following production method.

In the case of using silica fine powder as an example, a silica fine powder is produced by vapor-phase oxidation of a silicon halide compound, and the obtained silica fine powder is subjected to a hydrophobizing treatment to convert a non-spherical silica fine powder. To manufacture. In particular, in the case of gas phase oxidation, it is preferable to bake at a high temperature such that the primary particles of silica coalesce.

Of the non-spherical inorganic oxide fine particles (B) obtained by coalescing the primary particles thus obtained, relatively coarse coalesced particles are sampled to satisfy the condition of the average particle diameter in the presence state on the toner particles. It is particularly preferable to use one having a controlled particle size distribution.

The non-magnetic toner is used in an amount of 0.1 to 2 parts per 100 parts by weight of the non-magnetic toner to stabilize the charge amount of the toner.
It has inorganic oxide fine particles (A) in an amount of 0.2 to 2 parts by weight, preferably 0.2 to 2 parts by weight in terms of imparting fluidity, more preferably 0.2 to 1.5 parts by weight in terms of improving fixability. Good. On the other hand, in order to stabilize the bulk density of the developer, the non-magnetic toner is used in an amount of 0.3 to 3 parts per 100 parts by weight of the non-magnetic toner.
Parts by weight, preferably from 0.3 to
2.5 parts by weight, more preferably 0.3 to 2 parts by weight for non-spherical inorganic oxidation for stability in storage under high humidity, and 0.3 to 1.5 parts by weight for OHP permeability Particle (B)
It is desirable to have.

In the present invention, the inorganic oxide fine particles (A) are 0.5 μm × 0.5 μm on the surface of the toner particles.
Preferably, there are 5 or more per m area,
More preferably, 7 or more and 10 or more are particularly preferable. In addition, non-spherical inorganic oxide fine particles (B)
Preferably, 1 to 30 particles are present per 1.0 μm × 1.0 μm area on the surface of the toner particles, more preferably 1 to 25, and even more preferably 5 to 25 particles. When 5 or more inorganic oxide fine particles (A) are present per 0.5 μm × 0.5 μm area of the toner particle surface, the fluidity of the toner is maintained at an appropriate level, and high image quality and high image density are obtained. You can get the picture,
If there are less than five, the fluidity of the toner is insufficient, and the density of the obtained image tends to decrease.

In addition, the non-spherical inorganic oxide fine particles (B) are contained in an amount of 1 to 1.0 μm × 1.0 μm per toner particle surface.
When there are 30, the change in the bulk density of the developer is suppressed to be small, and a stable image density can be obtained.
When more than 30 particles are present, the non-spherical inorganic oxide fine particles (B) are easily released from the surface of the toner particles, and the latent image carrier is easily scraped or scratched.

One example of a method for distinguishing between the inorganic oxide fine particles (A) and the non-spherical inorganic oxide fine particles (B) on the surface of the toner particles is as follows. There is a method of judging based on the difference between the two, and a method of judging by detecting a specific element using an X-ray microanalyzer.

[0092] The inorganic oxide fine particles (A) existing as primary particles or secondary particles as in the present invention, and the non-spherical inorganic oxide fine particles (B) produced by aggregating a plurality of particles are used as toner. By externally adding the particles, the fluidity of the developer can be maintained for a long time, and the change in the bulk density of the developer can be suppressed. More specifically, the inorganic oxide fine particles (A) impart fluidity to the toner, and the non-spherical inorganic oxide fine particles (B) function as a spacer between toner particles or between a toner particle and a carrier. The fine particles (A) are prevented from being embedded in the surface of the toner particles, and the change in the bulk density of the developer is suppressed.

Accordingly, by detecting the change in the magnetic permeability of the developer using the developer having the inorganic oxide fine particles (A) and the non-spherical inorganic oxide fine particles (B) and the inductance of the coil, the toner concentration can be reduced. By combining the controlling means, the toner concentration in the developer can be appropriately maintained for a long time.

In order to improve transferability and / or cleaning performance, inorganic or organic particles having a primary particle size of 50 nm or more (preferably having a specific surface area of less than 50 m ² / g) are preferably added. one of. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, and spherical resin particles are preferably used.

In the toner of the present invention, other additives such as lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder; cerium oxide powder, silicon carbide Powder,
Abrasives such as strontium titanate powder; anti-caking agents such as titanium oxide powder and aluminum oxide powder; or conductivity imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder, and organic fine particles of opposite polarity Also, a small amount of inorganic fine particles can be used as a developing property improver.

The carrier used in the present invention is a spherical magnetic powder-dispersed carrier in which magnetic powder is dispersed in a binder resin, and includes those which achieve the apparent density or compressibility of the developer described below. This will be described in more detail.

As the carrier, the carrier has a weight average particle size of 15 to 60 μm, preferably 20 to 60 μm, more preferably 20 to 45 μm, and carrier particles having a particle size smaller than 22 μm are 20% by weight or less, preferably 0.05 to 15% by weight, more preferably 0.1 to 12%
Carrier particles having a particle size of less than 16 μm by weight are less than 3% by weight, preferably less than 2% by weight, more preferably less than 1% by weight.

When the weight average particle size of the carrier is larger than 60 μm, the uniformity of the solid image and the reproducibility of fine dots tend to decrease. The weight average particle size of the carrier is 1
When the thickness is less than 5 μm, the developing carrier easily adheres to the photoreceptor, causing damage to the photoreceptor and causing image deterioration.

The amount of coarse powder of the carrier having a particle size of 62 μm or more closely correlates with the sharpness of the image.
% By weight. When the particle size distribution is out of the range, the change in bulk density becomes large, and it becomes difficult to achieve a suitable degree of compression. When the amount of fine powder is further increased, carrier adhesion and when the amount of coarse powder is increased, fog and image density are liable to occur.

The shape of the carrier used in the present invention has a shape factor SF-1 of 100 to 140. Further, the shape factor SF-2 is preferably from 100 to 120.

When the shape factor SF-1 exceeds 140, the carrier deviates from a sphere, or when the SF-2 is 120
In the case of exceeding, the unevenness on the surface of the carrier becomes remarkable. As in the case of the toner particles described above, if the toner is non-spherical or has irregularities on the surface, the surface is scraped off by friction due to contact between the carriers or the toner particles at the time of stirring, and gradually approaches a spherical shape. Change becomes large. In a carrier having a shape factor SF-1 of more than 140 or SF-2 of more than 120, the shape change is large, the bulk density change is large, and the change in the magnetic permeability of the developer is performed by utilizing the coil inductance. The toner density detection sensor to be measured is likely to output an inappropriate output.

The carrier used in the present invention has a volume resistivity of 10 ⁹ to 10 ¹⁵ Ωcm. More preferably, it is larger than 10 ¹³ Ωcm and 10 ¹⁵ Ωcm.

When the volume resistivity of the carrier is less than 10 ⁹ Ωcm, the latent image is disturbed due to the injection of the developing bias in the developing region because the resistance is low. When the volume resistance value of the carrier exceeds 10 ¹⁵ Ωcm, the carrier itself is charged up, and the ability to impart charge to the replenishment toner tends to decrease.

The carrier used in the present invention is a magnetic powder-dispersed resin carrier in which a magnetic powder such as iron powder or ferrite iron oxide is dispersed in a resin. A polymerized resin carrier produced by a polymerization method is more preferable in that the change in compressibility is small, and a polymerized resin containing a magnetic powder and a non-magnetic metal oxide in that the magnetic properties can be arbitrarily controlled. Carriers are particularly preferred.

As the non-magnetic metal oxide, Fe ₂ O ₃ ,
Al ₂ O ₃ , SiO ₂ , CaO, SrO, MnO or mixtures thereof are preferred.

The above magnetic powder is preferably subjected to a lipophilic treatment, if necessary. At that time, after surface treatment with silica, alumina, titania to improve hydrophobicity,
Lipophilic treatment may be performed.

Similarly, it is preferable that the nonmagnetic metal oxide is also subjected to a lipophilic treatment.

Examples of the resin in which the magnetic powder is dispersed include a styrene- (meth) acrylic copolymer, a polyester resin, an epoxy resin, a styrene-butadiene copolymer, an acid resin, and a melamine resin.

Among them, it is preferable to contain a phenol resin. When a phenolic resin is contained, heat resistance and solvent resistance are excellent, and when the surface is coated with a resin, coating can be performed well.

The carrier used in the present invention is a carrier produced by a polymerization method.
It is preferable for uniform transportability of the developer.

It is preferable that the carrier particles are bound by using phenol obtained by curing magnetic fine particles as a matrix.

A method for manufacturing a carrier will be described.

A phenol and an aldehyde are reacted in an aqueous medium in the presence of a basic catalyst in the presence of a magnetic powder and a suspension stabilizer.

The phenols used here include:
Phenol, m-cresol, p-tert-butylphenol, o-propylphenol, resorcinol,
Examples include alkylphenols such as bisphenol A, and compounds having a phenolic hydroxyl group such as halogenated phenols in which part or all of a benzene nucleus or an alkyl group is substituted with a chlorine atom or a bromine atom. Most preferred. When a compound other than phenol is used as phenols, particles are difficult to generate, or even if particles are generated, they may have an irregular shape.
Phenol is most preferred.

The aldehydes used include:
Formaldehyde and furfural, in either form of formalin or paraformaldehyde, are included.
Formaldehyde is particularly preferred.

As the basic catalyst to be used, the basic catalyst used in the production of ordinary resol resins is used.
For example, aqueous ammonia, hexamethylenetetramine and alkylamines such as dimethylamine, diethyltriamine and polyethyleneimine can be mentioned. The molar ratio of these basic catalysts to phenols is 0.02 to 0.5.
3 is preferred.

When the phenols and aldehydes are reacted in the presence of a basic catalyst, the magnetic powders to be coexistent include the magnetic powders as described above. The amount is
It is preferably 0.5 to 200 times the weight of phenols. Further, considering the saturation magnetization value of the carrier particles and the particle strength, the ratio is more preferably 4 to 100 times.

The particle diameter of the magnetic powder is preferably from 0.01 to 10 μm, and considering the dispersion of the fine particles in an aqueous medium and the strength of the generated carrier particles, the particle size is 0.05 to 10 μm.
It is preferably about 5 μm.

Examples of the suspension stabilizer include hydrophilic organic compounds such as carboxymethylcellulose and polyvinyl alcohol, fluorine compounds such as calcium fluoride, and inorganic salts substantially insoluble in water such as calcium sulfate.

When a suspension stabilizer is used, it is preferably added in an amount of 0.2 to 10% by weight, more preferably 0.5 to 3.5% by weight, based on the phenol.

The reaction in the production method is carried out in an aqueous medium. In this case, the amount of water charged is preferably such that, for example, the solid content of the carrier is 30 to 95% by weight. It is desirable that the content be 90% by weight.

The reaction is carried out with stirring at a heating rate of 0.5 to 1.5.
C./min, preferably 0.8 to 1.2.degree. C./min., And gradually raise the temperature to a reaction temperature of 70 to 90.degree. C., preferably 83 to 87.degree. C. for 60 to 150 minutes, preferably 80 to 90.degree.
Incubate for 110 minutes. In such a reaction, a curing reaction proceeds simultaneously with the reaction to form a cured phenolic resin matrix.

After the reaction and curing as described above, the reaction product is cooled to 40 ° C. or lower, and an aqueous dispersion of spherical particles in which magnetic fine particles are uniformly dispersed in a cured phenol resin matrix is obtained.

Next, the aqueous dispersion is separated into solid and liquid by a conventional method such as filtration and centrifugation, and then washed and dried.
Carrier particles in which magnetic powder is dispersed in a phenol resin matrix are obtained.

The method of the present invention can be carried out by either a continuous method or a batch method, but usually employs a batch method.

Further, a carrier in which the surface is coated with a resin using the resin carrier in which the magnetic powder is dispersed as described above as core material particles is more preferably used. As the resin for coating the surface of the core material particles, a specific silicone resin, a fluorine resin, a copolymer of a fluorine resin and an acrylic resin, or a mixture thereof can be preferably used. By coating the resin particles in which the magnetic powder is dispersed with a resin, the so-called toner spent, in which the toner adheres to the carrier surface, is controlled, and the charge amount is easily controlled.

As a method for forming a resin coating layer on the surface of the core material particles, the resin composition is dissolved in an appropriate solvent, the core material particles are immersed in the obtained solution, and then the solvent is removed, dried, and heated at a high temperature. A method of baking; or a method of suspending carrier core particles in a fluidizing system, spraying and applying a solution in which the resin composition is dissolved, drying and baking at a high temperature; Alternatively, any method of mixing with an aqueous emulsion can be used.

The method preferably used in the present invention is a method wherein 5% by weight of a polar solvent such as ketones and alcohols is used.
As described above, a method of using a mixed solvent containing water in an amount of 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight in 100 parts by weight of a solvent containing preferably 20% by weight or more includes a reactive silicone resin. This is preferable for firmly adhering to the core particles. If the amount of water is less than 0.1 part by weight, the hydrolysis reaction of the reactive silicone resin is not sufficiently performed, and it is difficult to coat the core material particles in a thin layer and evenly. It becomes difficult, and conversely, the coating strength decreases.

The carrier used in the present invention preferably has a saturation magnetization σ ₁₀₀₀ of 20 to 45 Am ² / g with respect to an applied magnetic field of _1,000 Oersteds.
More preferably, it is 25 to 42 Am ² / g. Further, the coercive force is preferably 5 to 300 Oe, more preferably 10 to 200 Oe.

When σ ₁₀₀₀ is 20 to 40 Am ² / g,
Since the change in the bulk density of the developer is small, it is suitable for the toner density detection system of the present invention. When σ ₁₀₀₀ is less than 20 Am ² / g, the carrier easily adheres to the latent image carrier in the development area, and the latent image carrier is easily scraped and scratched.
_{When 1000} is larger than 45 Am ² / g, the compression of the developer in the developing device is increased, so that the deterioration of the developer is accelerated,
Fog tends to occur.

A coercive force of 5 to 300 Oersted is preferable since the change in bulk density is small, especially when the coercive force is left for a long time under high humidity. If the coercive force is less than 5 Oe, the change in bulk density under low humidity and high humidity greatly changes due to tribo, and when the coercive force is greater than 300 oersteds, the mixing property of the replenishment toner decreases. Fogging is likely to occur.

In the present invention, a two-component developer is prepared by mixing a carrier and a toner. The mixing ratio is 1 to 15% by weight, preferably 3 to 15% by weight, as the toner concentration in the two-component developer. Good results are usually obtained with 12% by weight, more preferably 5-10% by weight. If the toner concentration is less than 1% by weight, the image density will be low. If the toner concentration is more than 15% by weight, fog and scattering inside the machine will increase, and the useful life of the two-component developer will be reduced.

In the present invention, it is preferable to add at least one external additive to a part or all of the magnetic powder-dispersed carrier before mixing the carrier and the toner into a developer. . By adding an external additive in advance, the change in the ability to impart charge to the toner is reduced,
As a result, even after being left for a long time, the change in the bulk density and the change in the amount of charge of the developer are small, and very stable toner density control is achieved.

In the present invention, the inorganic oxide fine particles previously added to the carrier include the above-mentioned inorganic oxide fine particles (A) or non-spherical inorganic oxide fine particles (B).
However, non-spherical inorganic oxide fine particles (B) are preferably used in order to allow the particles to remain on the carrier for a long period of time and to reduce the change in bulk density.
Furthermore, in order to adhere to some extent by electrostatic force with the carrier, as the material, inorganic oxides containing silica,
Preferably, the surface of the silica is desirably hydrophobized. The addition amount at this time is preferably 0.001 to 0.2 parts by weight based on 100 parts by weight of the carrier.

Japanese Patent Application Laid-Open No. 4-124677 proposes a developer in which inorganic oxide particles are preliminarily attached to a carrier. This developer monitors the image density and controls the toner density from the image density. This is a content for reducing the change in the amount of charge of the developer used in the method, and the means / effect for suppressing the change in the bulk density as in the present invention is not described, and is completely different.

In the present invention, the degree of compression of the developer is 5 to 5.
It is preferable that the apparent density is 19% and the apparent density is 1.2 to 2.0 g / cm ³ . When the compression degree and the apparent density of the developer are within the above ranges, even when the toner is reduced in particle size, the deterioration of the toner is suppressed, and the bulk density due to the external additive being embedded on the surface of the toner particles at the time of durability is reduced. Change is reduced.

The latent image carrier (photoreceptor) used in the present invention
An example of a preferred embodiment will be described below.

Examples of the conductive substrate include metals such as aluminum and stainless steel, aluminum alloys and indium oxide-tin oxide alloys, plastics having a coating layer of these metals and alloys, paper and plastic impregnated with conductive particles, and the like.
Cylindrical cylinders and films such as plastics with conductive polymers are used.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coating properties are improved, the substrate is protected, the defect is coated on the substrate,
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate and protecting the photosensitive layer against electrical breakdown. The undercoat layer is polyvinyl alcohol, poly-N-vinyl imidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue,
It is formed by materials such as gelatin, polyurethane and aluminum oxide. The film thickness is usually 0.1 to 10 μm
m, preferably about 0.1 to 3 μm.

The charge generation layer is made of an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, a squarylium dye, a pyrylium salt, a thiopyrium salt, a triphenylmethane dye, selenium or amorphous silicon. Such a charge generating substance as an inorganic substance is dispersed in a suitable binder resin and coated. Alternatively, it is formed by vapor deposition. As the binder resin, can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin,
Examples include polystyrene resin, acrylic resin, methacrylic resin, phenolic resin, silicone resin, epoxy resin, and vinyl acetate resin. The amount of the binder resin contained in the charge generation layer is 80% by weight or less, preferably 40% by weight or less. Further, the thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transporting layer is formed by dissolving a charge transporting material in a solvent together with a binder resin if necessary, and applying the solution. The film thickness is generally 5 to 40 μm.
As the charge transporting substance, a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene, or phenanthrene in a main chain or a side chain; a nitrogen-containing cyclic compound such as indole, carbazole, oxadiazole, or pyrazoline; a hydrazone compound; Styryl compounds; inorganic compounds such as selenium, selenium-tellurium, amorphous silicon and cadmium sulfide.

Examples of the binder resin for dispersing the charge transport material include polycarbonate resin, polyester resin, polymethacrylate, polystyrene resin, and the like.
Acrylic resin, resin such as polyamide resin, poly-N-
Organic photoconductive polymers such as vinyl carbazole and polyvinyl anthracene are exemplified.

The latent image carrier used in the present invention is
It is preferable to have a charge injection layer as a layer farthest from the support, that is, a surface layer. The volume resistivity of the charge injection layer is set to 1 × 10 ⁸ Ωcm to 1 × 10 ¹⁵ Ωcm in order to obtain sufficient chargeability and to prevent image deletion.
It is particularly preferable that 1 × 1
It is preferably from 0 ¹⁰ Ωcm to 1 × 10 ¹⁵ Ωcm, and more preferably from 1 × 10 ¹⁰ Ωcm to 1 × 10 ¹³ Ωcm in consideration of environmental fluctuations and the like. If it is less than 1 × 10 ⁸ Ωcm, the charged charge is not held in the surface direction in a high humidity environment, so that image flow may easily occur. If it exceeds 1 × 10 ¹⁵ Ωcm, the charged charge from the charging member can be sufficiently injected and held. And there is a tendency for poor charging to occur. By providing such a functional layer on the surface of the latent image carrier, it plays a role of holding the charged charge injected from the charging member, and further plays a role of releasing this charge to the latent image carrier support member during light exposure, Reduce residual potential. Further, by employing such a configuration by using the charging member and the latent image carrier according to the present invention, the charging start voltage Vth is small, and the charging potential of the latent image carrier is almost 90% of the voltage applied to the charging member. It has become possible to converge as described above.

For example, the absolute value of the charging member is 100 to 20.
When a DC voltage of 00 V is applied at a process speed of 1000 mm / min or less, the charging potential of the latent image bearing member having the charge injection layer of the present invention is set to 80% or more of the applied voltage, and further to 9%.
It can be 0% or more. On the other hand, the charging potential of the latent image carrier obtained by the conventional charging using the discharge is about 30% when the applied voltage is 700 V DC.
It was only 200V.

The charge injection layer is composed of an inorganic layer such as a metal vapor deposition film or a conductive fine particle resin dispersion layer in which conductive fine particles are dispersed in a binder resin.
The conductive fine particle resin dispersion film is formed by applying an appropriate coating method such as a dipping coating method, a spray coating method, a roll coating method, and a beam coating method. Further, a resin formed by mixing or copolymerizing an insulating binder resin with a resin having high light transmittance and ionic conductivity, or a resin formed of a single resin having a medium resistance and photoconductive properties may be used. In the case of the conductive fine particle dispersed film, the amount of the conductive fine particles is preferably 2 to 190% by weight based on the binder resin. If the amount is less than 2% by weight, it is difficult to obtain a desired volume resistance value. If the amount is more than 190% by weight, the film strength is reduced, and the charge injection layer is easily scraped off. Is likely to be shorter.

As the binder resin for the charge injection layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent for these resins may be used alone or in combination of two or more.
Furthermore, when a large amount of conductive fine particles are dispersed, the conductive fine particles and the like are dispersed using a reactive monomer or a reactive oligomer and coated on the surface of the latent image carrier, and then cured by light or heat. Preferably. When the photosensitive layer is made of amorphous silicon, the charge injection layer is made of S
Preferably it is iC.

Examples of the conductive fine particles dispersed in the binder resin of the charge injection layer include metals and metal oxides, and preferably zinc oxide, titanium oxide, tin oxide, antimony oxide, and the like. Indium oxide, bismuth oxide,
There are ultrafine particles such as tin oxide-coated titanium oxide, tin-coated indium oxide, antimony-coated tin oxide, and zirconium oxide. These may be used alone or as a mixture of two or more. Generally, when particles are dispersed in the charge injection layer, it is necessary that the particle diameter of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles. The particle size of the conductive and insulating particles to be formed is preferably 0.5 μm or less.

In the present invention, the charge injection layer preferably contains lubricant particles. The reason is that the friction between the latent image carrier and the charging member during charging is reduced, so that the charging nip is enlarged and the charging characteristics are improved. In particular, it is preferable to use a fluorine resin, a silicone resin or a polyolefin resin having a low critical surface hearing as the lubricant particles. More preferably, ethylene tetrafluoride resin (P
TFE) is used. In this case, the amount of the lubricant particles is 2 to 50% by weight, preferably 5 to 50% by weight, based on the binder resin.
40% by weight. If the amount is less than 2% by weight, the amount of the lubricant particles is not sufficient, so that the charging characteristics are not sufficiently improved.
On the other hand, if it exceeds 50% by weight, the resolution of the image and the sensitivity of the photoreceptor are greatly reduced.

In the present invention, the thickness of the charge injection layer is 0.1
It is preferably from 10 to 10 μm, particularly preferably from 1 to 7 μm.

When the film thickness is less than 0.1 μm, the resistance to minute scratches is lost, and as a result, an image defect due to poor injection occurs. When the film thickness exceeds 100 μm, the image tends to be disturbed due to diffusion of injected charges.

In the present invention, the fluorine atom-containing resin fine particles used for the latent image carrier are made of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, or tetrafluoroethylene-perfluoroalkylvinyl ether copolymer. Coalesce, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and one or more selected from tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymer It is configured. Commercially available fluorine atom-containing resin fine particles can be used as they are. Those having a molecular weight of 0.3000 to 5,000,000 can be used, and 0.01 to 10 μm,
Preferably, those having a particle size of 0.05 to 2.0 μm can be used.

In many cases, the protective layer and the photosensitive layer are formed by dispersing the fluorine atom-containing resin fine particles, the charge generating material, and the charge transporting material in a binder resin having film forming properties. Such binder resins include polyester, polyurethane, polyacrylate, polyethylene,
Polystyrene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin .

The conductive support of the latent image carrier is made of iron, copper,
Gold, silver, aluminum, zinc, titanium, lead, nickel,
Metals and alloys such as tin, antimony, and indium, or oxides, carbon, and conductive polymers of the metals can be used. The shapes include a drum shape such as a cylindrical shape and a cylindrical shape, a belt shape, and a sheet shape. The conductive material may be formed as it is, used as a paint, deposited, or processed by etching or plasma processing.

Next, an image forming apparatus of the present invention using a two-component developer will be described.

The image forming apparatus of the present invention carries a two-component developer having a toner and a carrier on a developer carrier.
The latent image is conveyed to a development area and is developed on the latent image carrier with toner contained in the two-component developer.

As the charging method in the image forming apparatus of the present invention, a corona charging method or a charging method using a pin electrode can be used. However, a charging roller, a charging blade, a conductive brush and a magnetic brush are used for the latent image carrier. Contact charging, in which charging is performed by contact, is preferably used. In particular, it is preferable to perform charging by bringing the magnetic brush into contact with the surface of the latent image carrier in terms of durability of the latent image carrier. In this case, as a configuration of the charger, as a magnetic particle holding member for charging,
A magnet roll or a conductive sleeve having a magnet roll inside and coated uniformly with magnetic particles for charging is preferably used.

As the magnetic particles for charging used in the present invention, so-called hard ferrites such as strontium, barium and rare earth, or ferrites such as magnetite, copper, zinc, nickel and manganese are used.

The weight average particle diameter of the magnetic particles for charging is 5 to 5.
The thickness is preferably 45 μm, more preferably 10 to 45 μm, and still more preferably 20 to 40 μm.

When the weight average particle diameter of the magnetic particles for charging is smaller than 5 μm, the chargeability is good, but the magnetic binding force is reduced, and as a result, the chargeable magnetic particles detached from the conductive magnetic brush charger are latent. Since the development process is performed in a state where it is also adhered to the surface of the image carrier, the charging magnetic particles may be mixed into the developing container, which may disturb the electrostatic latent image during development. Weight average particle diameter of magnetic particles for charging is 45μ
If it is larger than m, the brush ears of the charging magnetic particles are in a coarse state, and charging unevenness is likely to occur, and image quality is likely to deteriorate.

[0160] The volume resistivity of the charging member used in the present invention, 10 ⁷ ~10 ¹¹ Ωcm, preferably lying good is less than 10 ⁷ [Omega] cm or more 10 ⁹ [Omega] cm.

When the volume resistance of the charging member is less than 10 ⁷ Ωcm, it is difficult to prevent the magnetic particles as the charging member from adhering to the latent image carrier. If the volume resistivity of the charging member exceeds 10 ¹¹ Ωcm, the ability to impart charging to the latent image carrier is reduced, especially under low humidity, and poor charging is likely to occur.

Further, it is more preferable that the charging magnetic particles have a surface layer on the surface of the core material. Examples of such a surface layer include a coupling agent such as a silane coupling agent and a titanium coupling agent, a conductive resin or a resin containing conductive fine particles (preferably a fluororesin or a silicone resin).

It is also possible to use magnetic particles for charging which are not coated with resin and magnetic particles for charging which are coated with resin. The mixing ratio in that case is preferably 50% by weight or less based on the total weight of the magnetic particles in the charger. 5
If the content is more than 0% by weight, the effect of the charging magnetic particles treated with the above-mentioned coupling agent is reduced.

From this, the weight loss on heating was 0.5% by weight.
And more preferably 0.2% by weight
It is as follows.

Here, the heating loss refers to a temperature from 150 ° C. to 800 ° C. in a nitrogen atmosphere in an analysis using a thermobalance.
Up to the weight loss.

The closest gap between the charging magnetic particle holding member and the latent image carrier is preferably 0.3 mm to 2.0 mm. If the distance is less than 0.3 mm, depending on the applied voltage, a leak may occur between the conductive portion of the magnetic particle holding member for charging and the latent image carrier, possibly damaging the latent image carrier.

The amount of the magnetic particles for charging held by the magnetic particle holding member for charging is preferably 50 to 500 mg / c.
m ² , more preferably 100 to 300 mg / cm ² , can provide stable chargeability.

When using the injection charging method, the charging bias applied to the charging member may be only a DC component, but if a slight AC component is applied, the image quality is improved. Although the AC component depends on the process speed of the device,
At a frequency of about 00 Hz to 10 kHz, the peak-to-peak voltage of the applied AC component is preferably 1000 V or less.
If the voltage exceeds 1000 V, the potential of the latent image carrier is obtained with respect to the applied voltage, so that the latent image surface may be waved in potential, causing fogging and light density. In the method using electric discharge,
Although the AC component depends on the process speed of the apparatus, it is preferable that the applied AC component has a peak-to-peak voltage of 1000 V or more at a frequency of about 100 Hz to 10 kHz and twice or more the discharge starting voltage. This is to obtain a sufficient leveling effect on the surface of the magnetic brush and the latent image carrier. As the waveform of the applied AC component, a sine wave, a rectangular wave, a sawtooth wave, or the like can be used.

Further, extra charging magnetic particles may be held and circulated in the charger. As the image exposure unit, a known unit such as a laser or an LED is used.

The charging magnetic brush may move in the same direction or in the opposite direction at the contact portion with respect to the moving direction of the latent image carrier. It is preferable to move in the opposite direction from the viewpoint of increasing the chance of contact with the charging magnetic brush.

It is preferable to control the charge of the transfer residual toner when charging the latent image carrier so that the transfer residual toner on the latent image carrier can be collected by the developer carrier in the developing step. When the latent image carrier is charged by contact charging, transfer residual toner adheres to the charger. Such toner is conveyed to a developing area using the surface of the latent image carrier, and transferred to a developing area. Collected at.

When the transfer residual toner attached to the charger is conveyed to the developing portion by utilizing the surface of the latent image carrier and collected and reused, it is possible without changing the charging bias. It is preferable to change the charging bias so that the charging bias is more easily transferred to the latent image carrier than the charging device. Especially,
During transfer jams or when images with a high image ratio are taken continuously, an excessive amount may adhere to the charger, and in this case, the image may remain on the latent image carrier during operation of the electrophotographic apparatus. It is preferable that the charging bias is changed by using the time during which the toner is not formed, and the toner is moved from the charger to the latent image carrier. The time during which no image formation is performed is during pre-rotation, post-rotation, and between transfer sheets. As a bias at which the toner easily comes out of the charger, the voltage between the peaks of the AC component is set to a small value or a DC component. Alternatively, there is a method in which the peak-to-peak voltage is made the same and the waveform is changed to lower the AC execution value.

When the transfer residual toner is controlled in the charging step and the transfer residual toner is collected in the developing step, the latent image carrier can be cleaned without using a cleaning member such as a cleaning blade. Become.

When the contact charging and the cleaning method for recovering the transfer residual toner in the developing step are combined, the external additive on the toner particle surface is easily embedded in the toner particles in the charging step, so that the change in the bulk density of the toner is reduced. From the viewpoint of suppression, the conditions are more severe, but can be achieved without any problem in the present invention.

Next, the developing method will be described.

According to the present invention, for example, of the developing sleeve (developer carrying member) and the magnet roller incorporated therein, the magnet roller is fixed and the developing sleeve is rotated alone, so that the two-component developer is placed on the developing sleeve. And develops the electrostatic latent image held on the surface of the latent image carrier with the two-component developer.

In the present invention, it is preferable to apply a developing bias in the developing area to develop the electrostatic latent image with the toner of the two-component developer.

A particularly preferred developing bias will be described in detail below.

In the present invention, in order to form a developing electric field in the developing area between the latent image carrier and the developer carrier, a developing voltage having a discontinuous AC component as shown in FIG. , The latent image held on the latent image carrier is preferably developed with the toner of the two-component developer on the developer carrier. Specifically, the developing voltage includes a first voltage for directing toner from the latent image carrier to the developer carrier in the development area, and a second voltage for directing toner from the developer carrier to the latent image carrier. And applying a third voltage between the first voltage and the second voltage to the developer carrier to form a developing electric field between the latent image carrier and the developer carrier.

Further, the first voltage for directing toner from the latent image carrier to the developer carrier and the second voltage for directing toner from the developer carrier to the latent image carrier are applied to the developer carrier. Total time, that is, the time during which the third voltage between the first voltage and the second voltage is applied to the developer carrier, that is, the time during which the AC component is acting (T ₁ ),
It is particularly preferable to lengthen the rest time (T ₂ ) of the AC component for the purpose of rearranging the toner on the latent image carrier and faithfully reproducing the latent image.

Specifically, an electric field in which toner travels from the latent image carrier to the developer carrier between the latent image carrier and the developer carrier in the development area, and the electric field from the developer carrier to the latent image carrier After the electric field to which the toner is directed is formed at least once, in the image portion of the latent image carrier, the toner moves from the developer carrier to the latent image carrier, and in the non-image portion of the latent image carrier, the toner moves to the latent image carrier. The latent image held on the latent image carrier is developed with the toner of the two-component developer carried on the developer carrier by forming an electric field directed from the developer carrier to the developer carrier for a predetermined time. In the image portion of the latent image carrier, the total time (T ₁ ) for forming the electric field in which the toner travels from the latent image carrier to the developer carrier and the electric field in which the toner travels from the developer carrier to the latent image carrier is changed. Moves from the developer carrier to the latent image carrier, and the latent image carrier In the non-image portion of the time of forming an electric field in which the toner is directed from the latent image bearing member to the developer bearing member (T
It is preferable to make ₂ ) longer.

In the developing method of forming and developing the above-described specific developing electric field, that is, an alternating electric field, when the developing is performed using the developing electric field for periodically turning off the alternating electric field, the carrier adheres to the latent image carrier. It is less likely to occur. The reason for this is not yet clear, but is considered as follows.

That is, in the case of the conventional continuous sine wave or rectangular wave, if the electric field strength is increased in order to achieve a high image quality density, the toner and the carrier are united to form a gap between the latent image carrier and the developer carrier. Reciprocates, and as a result, the carrier strongly rubs against the latent image carrier, and carrier adhesion occurs. This tendency becomes more remarkable as the amount of the fine powder carrier increases.

However, when a specific alternating electric field as in the present invention is applied, the toner or carrier does not reciprocate between the developer carrier and the latent image carrier in one pulse, so that the surface potential of the subsequent latent image carrier is not increased. When the potential difference V _cont of the DC component of the developing bias and V _cont is less than V _cont , V _cont acts to fly the carrier from the developer carrier, but the magnetic characteristics of the carrier and the magnetic flux in the developing area of the magnet roller By controlling the density, carrier adhesion can be prevented, and when V _cont > 0, the magnetic field force and V _cont
Works to attract the carrier toward the developer carrier,
No carrier adhesion occurs.

The magnetic characteristics of the carrier are affected by the magnet roller incorporated in the developing sleeve, and greatly affect the developing characteristics and transportability of the developer.

In the present invention, the magnet roller is fixed on the developing sleeve containing the magnet roller, and the developing sleeve is rotated by itself, so that the carrier composed of the magnetic particles and the two-component developer composed of the insulating color toner are removed. When the electrostatic roller is circulated and transported on the developing sleeve and the electrostatic latent image held on the surface of the latent image carrier is developed by the two-component developer, the magnet roller has a pole configuration having repulsive poles, and the magnetic flux in the developing area The density is 500 to 1200 Gauss, and the saturation magnetization of the carrier is 20 to 70 Am ² /
When the weight is kg, the uniformity and the gradation reproducibility of the image in color copying are excellent, which is preferable.

When the saturation magnetization exceeds 70 Am ² / kg (for an applied magnetic field of 3000 Oersteds),
At the time of development, the brush-like spikes formed by the carrier and the toner on the developing sleeve facing the electrostatic latent image on the latent image carrier are in a tightly closed state, and the gradation and the reproduction of halftone are deteriorated. On the other hand, if it is less than 20 Am ² / kg, it becomes difficult to hold the toner and the carrier on the developing sleeve satisfactorily, and problems such as deterioration of carrier adhesion and toner scattering are likely to occur.

In the present invention, the direction of rotation of the developing sleeve may be the same as or opposite to the direction of rotation of the latent image carrier.

However, when the transfer residual toner is collected in the developing step, when the developing sleeve rotates in the opposite direction to the latent image carrier in the developing area, it is compared with the case where the developing sleeve rotates in the same direction. In addition, since the transfer residual toner remaining on the photoreceptor is favorably collected, the occurrence of problems such as fog and image memory is suppressed.

In the present invention, in order to regulate the amount of the developer carried on the surface of the developing sleeve, a developer regulating blade is arranged to face the developing sleeve.
In particular, it is preferable to arrange the developer regulating blade below the developer carrier. If the developer regulating blade is located above, uniform conveyance of the developer cannot be achieved unless compression is applied to overcome the gravity of the developer, and as a result, the frictional force between the agents due to the rotation of the developing sleeve is also reduced. Increase
As the developing sleeve rotates, the deterioration of the external additive is promoted, and the fluidity change from the initial toner is increased. A large variation in the fluidity of the toner indicates a large variation in the bulk density between the developers. The change in the bulk density is larger as the external additive is smaller, and the space between the developers is changed due to the deterioration of the external additive, so that the bulk density of the developer is changed. On the other hand, in the present invention, since the developer regulating blade is arranged below the developing sleeve, the developer does not need to be compressed enough to overcome gravity, and even if the amount of the developer accumulated near the blade is reduced, the developing amount is reduced. Uniform transportability of the developer is achieved, and as a result, deterioration due to compression of the developer can be suppressed, and a change in bulk density can be reduced.

Next, the developed toner image is transferred to a transfer material such as paper.

The transfer means contacts the latent image carrier,
It is possible to use a contact transfer unit such as a transfer blade and a transfer roller to which a transfer bias can be directly applied, or a non-contact transfer unit that performs transfer by applying a transfer bias from a corona charger.

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

The transfer residual toner remaining on the latent image carrier after the transfer can also be removed by using a cleaning member such as a cleaning blade in contact with the latent image carrier. As described above, the transfer residual toner can be removed by adjusting the charge of the transfer residual toner at the time of charging and collecting the toner in the developing step.

FIG. 1 is a schematic view showing an example of an image forming apparatus according to the present invention, and an embodiment of the present invention will be described with reference to FIG.

A magnetic brush made of magnetic particles 23 is formed on the surface of the transport sleeve 22 by the magnetic force of the magnet roller 21, and the magnetic brush is brought into contact with the surface of the photosensitive drum 1 to charge the photosensitive drum 1. A charging bias is applied to the transport sleeve 22 by a bias applying unit (not shown). Charged photosensitive drum 1
Then, an electrostatic image is formed by irradiating a laser beam 24 from an exposure device (not shown). The electrostatic image formed on the photosensitive drum includes a magnet roller 12 and is developed by toner 19a in developer 19 carried on developing sleeve 11 to which a developing bias is applied by a bias applying device (not shown). Is done.

Next, the flow of the developer will be described.

The developing container 4 is separated from the developing chamber R by the partition 17.
1. A stirring chamber R2 is provided, and developer conveying screws 13 and 14 are provided respectively. Above the stirring chamber R2, a toner storage chamber R3 containing the toner 18 for replenishment is provided, and a replenishing port 20 is provided below the storage chamber R3.

The developer transport screw 13 rotates to transport the developer in the developer R1 in one direction along the longitudinal direction of the developing sleeve 11 while stirring. The partition 17 is provided with openings (not shown) on the near side and the back side in the figure, and the developer conveyed to one side of the developing chamber R1 by the screw 13 passes through the opening of the partition 17 on one side, and the stirring chamber R2 and the developer conveying screw 14
Passed to. The rotation direction of the screw 14 is opposite to that of the screw 13, and the screw 13 is mixed with the screw 13 while stirring and mixing the developer in the stirring chamber R2, the developer delivered from the developing chamber R1, and the toner supplied from the toner storage chamber R3. Is transported in the agitating chamber R2 in the reverse direction, and is sent to the developing chamber R1 through the other opening of the partition wall 17.

To develop the electrostatic latent image formed on the photosensitive drum, first, the developer 19 in the developing chamber R 1 is pumped up by the magnetic force of the magnet roller 12 and is carried on the surface of the developing sleeve 11. The developer carried on the developing sleeve 11 is conveyed to the regulating blade 15 with the rotation of the developing sleeve 11, where it is regulated to a thin developer layer having an appropriate layer thickness. To the development area opposed to it. A magnetic pole (development pole) N1 is located at a position corresponding to the development area of the magnet roller 12, and the development pole N1 forms a development magnetic field in the development area. A magnetic brush of developer is generated in the development area. Then, the magnetic brush contacts the photosensitive drum 1, and the toner adhered to the magnetic brush and the toner adhered to the surface of the developing sleeve 11 are transferred to and adhered to the electrostatic latent image area on the photosensitive drum 1. The latent image is developed and visualized as a toner image.

After the development, the developer is supplied to the developing sleeve 11.
Is returned into the developing container 4 with the rotation of the magnetic poles S1, S
It is peeled off from the developing sleeve 11 by the repelling magnetic field between the two, and falls into the developing chamber R1 and the stirring chamber R2 to be collected.

By the above development, the developer 1 in the developing container 4 is
When the T / C ratio of 9 (mixing ratio of toner and carrier, that is, the toner concentration of the developer) decreases, the toner 18 falls from the toner storage chamber R3 into the stirring chamber R2 in an amount corresponding to the amount consumed in the development. The replenishment is performed, and the T / C of the developer 19 is maintained at a constant level. To detect the T / C ratio of the developer 19 in the container 4,
A toner concentration detection sensor that measures a change in the magnetic permeability of the developer using the inductance of the coil is used. still,
The toner concentration detection sensor has a coil (not shown) therein.

The regulating blade 15 disposed below the developing sleeve 11 and regulating the layer thickness of the developer 19 on the developing sleeve 11 is a non-magnetic blade made of a non-magnetic material such as aluminum or SUS316. The distance between the end and the surface of the developing sleeve 11 is 300 to 1000 μm, preferably 400 to 900 μm. This distance is 300
If it is less than μm, the magnetic carrier is clogged during this time, and the developer layer is likely to be uneven, and the developer necessary for good development cannot be applied. There is a problem that can not be. In order to prevent non-uniform coating (so-called blade jam) due to unnecessary particles mixed in the developer, the thickness is preferably 400 μm or more. If it is larger than 1000 μm, the amount of the developer applied on the developing sleeve 11 increases, so that a predetermined thickness of the developer layer cannot be regulated. Blade 15
, The toner is less regulated, and toner fogging is insufficient and fogging is likely to occur.

Even when the developing sleeve 11 is driven to rotate in the direction of the arrow, the magnetic carrier particle layer is separated from the surface of the sleeve by a balance between the restraining force based on magnetic force and gravity and the conveying force in the moving direction of the developing sleeve 11. Movement slows down. Of course, some fall under the influence of gravity.

Therefore, by appropriately selecting the arrangement positions of the magnetic poles N and N and the fluidity and magnetic properties of the magnetic carrier particles, the magnetic carrier particle layer is conveyed toward the magnetic pole N1 closer to the sleeve to form a moving layer. Due to the movement of the magnetic carrier particles, the developer is conveyed to the developing area with the rotation of the developing sleeve 11 and is used for development.

Further, the developed toner image is transferred onto a transfer material 25 being conveyed by a transfer blade 27 which is a transfer means to which a transfer bias is applied by a bias applying means 26, and is transferred onto the transfer material. The transferred toner image is fixed on the transfer material by a fixing device (not shown). In the transfer step, the transfer residual toner remaining on the photoreceptor without being transferred to the transfer material is adjusted in charge in the charging step, and is collected during development.

FIG. 3 is a schematic view of another image forming apparatus capable of performing the image forming method of the present invention.

The image forming apparatus main body is provided with a first image forming unit Pa, a second image forming unit Pb, a third image forming unit Pc, and a fourth image forming unit Pd.
Images of different colors are formed on the transfer material through the processes of latent image formation, development, and transfer.

The structure of each image forming unit provided in the image forming apparatus will be described using the first image forming unit Pa as an example.

The first image forming unit Pa has a 30φ electrophotographic photosensitive drum 61a as a latent image carrier, and this photosensitive drum 61a is rotated in the direction of arrow a. Reference numeral 62a denotes a primary charger as a charging unit, and a magnetic brush formed on the surface of a sleeve having a diameter of 16 mm is arranged so as to contact the surface of the photosensitive drum 61a. Reference numeral 67a denotes a laser beam for forming an electrostatic latent image on the photosensitive drum 61a, the surface of which is uniformly charged by the primary charger 62a, and is irradiated by an exposure device (not shown). Reference numeral 63a denotes a developing device as developing means for developing the electrostatic latent image carried on the photosensitive drum 61a to form a color toner image, and holds a color toner. 64a is a belt-like transfer material carrier 68 for transferring the color toner image formed on the surface of the photosensitive drum 61a.
The transfer blade 64a is a transfer blade serving as a transfer unit for transferring the transfer material onto the surface of the transfer material conveyed by the transfer member. The transfer blade 64a can contact the surface of the transfer material carrier 68 to apply a transfer bias.

In the first image forming unit Pa, after the photosensitive drum 61a is uniformly and primarily charged by the primary charger 62a, an electrostatic latent image is formed on the photosensitive drum by the exposure device 67a. The electrostatic latent image is developed using color toner, and the developed toner image is transferred to a belt-like transfer material carrying and transferring the transfer material at a first transfer portion (a contact position between the photosensitive drum and the transfer material). A transfer bias is applied from a transfer blade 64a in contact with the back surface of the body 68 to transfer the image to the surface of the transfer material.

When the toner is consumed by the development and the T / C ratio decreases, the decrease is detected by a toner concentration detection sensor 85 which measures the change in the magnetic permeability of the developer by using the inductance of the coil, and is consumed. The supply toner 65 is supplied according to the toner amount. The toner density detection sensor 85 has a coil (not shown) inside.

The present image forming apparatus has the same configuration as the first image forming unit Pa, and has the second image forming unit Pb, the third image forming unit Pc, and the color toner of different colors held in the developing device. Fourth of the fourth image forming unit Pd
And two image forming units. For example,
The first image forming unit Pa uses yellow toner, the second image forming unit Pb uses magenta toner, the third image forming unit Pc uses cyan toner, and the fourth image forming unit Pd uses black toner. The transfer of each color toner onto the transfer material is sequentially performed in the transfer section of the forming unit. In this step, while the registration is being performed, each color toner is superimposed on the same transfer material by one transfer of the transfer material, and when the transfer is completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. The sheet is sent to the fixing device 70 by a conveying means such as a conveying belt, and the final full-color image is obtained by a single fixing.

The fixing device 70 has a pair of 40φ fixing roller 71 and a 30φ pressing roller 72.
Has heating means 75 and 76 inside. 73
Is a web for removing dirt on the fixing roller.

The unfixed color toner image transferred onto the transfer material passes through a pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70, and is applied to the transfer material by the action of heat and pressure. Is established.

In FIG. 3, the transfer material carrier 68 is
It is an endless belt-shaped member, which is moved in the direction of arrow e by 80 drive rollers.
79 is a transfer belt cleaning device, 81 is a belt driven roller, and 82 is a belt static eliminator.
83 is a pair of registration rollers for conveying the transfer material in the transfer material holder to the transfer material carrier 68.

As the transfer means, contact transfer in which a transfer bias can be directly applied by contacting the back surface of a transfer material carrier such as a roller-shaped transfer roller instead of the transfer blade contacting the back surface of the transfer material carrier. Means can be used.

Further, a transfer bias is applied by applying a transfer bias from a corona charger arranged in a non-contact manner on the back side of a generally used transfer material carrier in place of the contact transfer means. May be used.

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

Hereinafter, the measurement method in the present invention will be described.

(1) Measurement of Magnetic Properties of Carrier A BHU-60 type magnetization measurement device (manufactured by Riken Keisoku) is used. About 1.0 g of a measurement sample is weighed, packed in a cell having an inner diameter of 7 mmφ and a height of 10 mm, and set in the above-mentioned apparatus. In the measurement, an applied magnetic field is gradually applied to change the maximum to 1,000 Oe. Next, the applied magnetic field is decreased, and finally a hysteresis curve of the sample is obtained on the recording paper. From this, the σ _{1000 '} coercive force is obtained.

(2) Measurement of Apparent Density Using a powder tester (manufactured by Hosokawa Micron), the apparent density A (g / cm ³ ) was measured with a sieve having an opening of 75 μm vibrated at an amplitude of 1 mm and passed therethrough. .

(3) Measurement of the degree of compression Using a powder tester (manufactured by Hosokawa Micron), the tap density P after 180 times of vertical reciprocation was measured.

[0224]

[Outside 1] (Where A represents the apparent density measured by the method of (2))
Was calculated.

(4) Method of Measuring SF-1 and SF-2 of Toner Particles, Carriers and External Additives A sample FE-SEM (S-800 manufactured by Hitachi, Ltd.) was used to enlarge the sample. 100 samples are randomly sampled, and the image information is transmitted through an interface, for example, to an image analyzer (Luzex II manufactured by Nicole).
The values introduced into I), analyzed, and calculated by the following equation are used as coefficients SF-1 and SF-2.

The magnification at the time of measurement was 10,000 times for toner particles, 2000 times for carriers, and 100,000 times for external additives.

[0227]

[Outside 2] (In the formula, MXLNG indicates the absolute maximum length of the particle, and AREA indicates the projected area of the particle.)

[0228]

[Outside 3] (Where PERI indicates the perimeter of the particle, and AREA indicates the projected area of the particle.)

(5) Measurement of average particle diameter of external additive, ratio of major axis to minor axis, and number of external additives present on toner particle surface The values of inorganic oxide fine particles (A) were measured by FE-SE.
M (S-800 manufactured by Hitachi, Ltd.) was used to take a photograph of the surface of the toner particles magnified 100,000 times, and the photograph was taken using the magnified photograph.

First, the average particle diameter of the inorganic oxide fine particles (A) on the toner particles is determined by measuring the major axis of the inorganic oxide fine particles (A) present on the enlarged photograph over 10 visual fields and calculating the average value. The average particle size was determined. Furthermore, the average value of the minor axis of the inorganic oxide fine particles (A) was determined in the same manner, and the ratio of the major axis to the minor axis of the inorganic oxide fine particles (A) was determined. In addition, among the parallel lines drawn so as to be in contact with the contour of the inorganic oxide fine particles (A), the distance between the parallel lines where the distance between the parallel lines is the maximum is defined as the long diameter, and the distance between the parallel lines where the distance between the parallel lines is the minimum is defined. Let the distance be the minor axis.

The number of the inorganic oxide fine particles (A) on the surface of the toner particles was 0.5 μm × 0.5
μm (50 mm x 50 m in a 100,000-fold enlarged photograph)
m) The number of the inorganic oxide fine particles (A) per area was counted in ten visual fields of an enlarged photograph, and the average value was calculated. When counting the number of the inorganic oxide fine particles (A), the inorganic oxide fine particles (primary or secondary particles) existing in the central portion of the enlarged photograph at a portion corresponding to 0.5 μm × 0.5 μm ( The number of A) was counted.

For the measurement of each numerical value of the non-spherical inorganic oxide fine particles (B), a photograph of the toner particle surface magnified 30,000 times by FE-SEM (S-800 manufactured by Hitachi, Ltd.) was taken, and the magnified photograph was taken. Was performed using

First, the average particle diameter of the non-spherical inorganic oxide fine particles (B) is determined by measuring the major axis of the non-spherical inorganic oxide fine particles (B) in an enlarged photograph over 10 visual fields, and using the average value as the average particle diameter. I asked for it. Furthermore, the average value of the minor axis of the non-spherical inorganic oxide fine particles (B) was determined in the same manner, and the ratio of the major axis to the minor axis of the non-spherical inorganic oxide fine particles (B) was determined.
In addition, among the parallel lines drawn so as to be in contact with the non-spherical inorganic oxide fine particles (B), the distance between the parallel lines at which the distance between the parallel lines is the maximum is defined as the long diameter, and the distance between the parallel lines at which the distance between the parallel lines is the minimum Let the distance be the minor axis.

The number of the non-spherical inorganic oxide fine particles (B) on the surface of the toner particles was 1.0 μm × 1.0 μm.
1.0 μm (30 mm × 30 in a 30,000-fold enlarged photograph)
mm) per area, the number of non-spherical inorganic oxide fine particles (B) was counted in ten visual fields of an enlarged photograph, and the average value was calculated. When counting the number of the non-spherical inorganic oxide fine particles (B), a 1.0 μm ×
Non-spherical inorganic oxide fine particles (B) existing in a portion corresponding to 1.0 μm were targeted.

(6) Measurement of Average Particle Size and Particle Size Distribution of Toner Particles and Carrier The average particle size and particle size distribution of toner particles and carrier were measured using a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co., Ltd.). Interface for outputting number distribution and volume distribution (made by Nikkaki) and P
C9801 personal computer (manufactured by NEC) is connected, and the electrolyte is 1% Nac using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON R-I
I (manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolytic aqueous solution 100 to
In 150 ml, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic
The volume distribution and the number distribution were calculated by measuring the volume and the number of toner particles having a size of 2 μm or more and the carrier using an aperture. Then, a volume-based weight average particle diameter (D ₄ ) obtained from the volume distribution according to the present invention and a number-based length average particle diameter (D ₁ ) obtained from the number distribution were obtained.

(7) Measurement of Volume Resistance Value of Developing Magnetic Carrier and Charging Conductive Magnetic Particle The volume resistance value was measured using the cell shown in FIG. That is, the cell A is filled with the sample 33, the lower electrode 31 and the upper electrode 32 are arranged so as to be in contact with the filled sample 33, a DC voltage of 1000 V is applied between the electrodes, and the current flowing at that time is measured with an ammeter. I asked by doing. still,
34 is an insulator. The measurement conditions were as follows: the contact area S of the filled sample 33 with the cell was 2 cm ² , and the thickness d was 3 m.
m, and the load on the upper electrode is 15 kg.

(8) Measurement of BET Specific Surface Area of External Additive The BET specific surface area was measured by using a specific surface area automatic soap 1 manufactured by QUANTACHROME.

About 0.1 g of a sample was weighed into a cell,
Deaeration is performed at 0 ° C. and a degree of vacuum of 1.0 × 10 ⁻³ mmHg or less for 12 hours or more. Thereafter, nitrogen gas was adsorbed while cooled with liquid nitrogen, and the BET specific surface area was determined by a multipoint method.

[0239]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. Hereinafter, all “parts” indicate “parts by weight”.

(Production Example 1 of Cyan Toner) To 710 parts of ion-exchanged water, 450 parts of an aqueous 0.1 M Na ₃ PO ₄ solution were added, and the mixture was heated to 60 ° C. Was stirred at 12000 rpm. To this, 68 parts of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing a calcium phosphate salt.

On the other hand, (monomer) styrene 165 parts n-butyl acrylate 35 parts (colorant) I. Pigment Blue 15: 3 15 parts was finely dispersed by a ball mill, and then (charge control agent) aluminum salicylate compound 2 parts (polar resin) saturated polyester resin 10 parts (release agent) ester wax (melting point 70 ° C.) 50 parts was added. Using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) heated to 60 ° C., the mixture was uniformly dissolved and dispersed at 12,000 rpm. Into this, 10 parts of a polymerization initiator 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved,
A polymerizable monomer composition was prepared.

The polymerizable monomer composition was placed in the aqueous medium, and the mixture was stirred at 10,000 rpm for 10 minutes with a TK homomixer at 60 ° C. in an N ₂ atmosphere. Granulated. Thereafter, the temperature was raised to 80 ° C. while stirring with a paddle stirring blade, and the reaction was performed for 10 hours. After completion of the polymerization reaction, the remaining monomer is distilled off under reduced pressure, and after cooling,
After adding hydrochloric acid to dissolve the calcium phosphate, the mixture was filtered, washed with water, and dried to give a weight average particle size of 6.5 μm, SF-1
Is 114 and SF-2 is 107.
I got

Anatase type hydrophobic titanium oxide (7 × 10 ⁹ Ωcm) having a BET specific surface area of 96 m ² / g treated with 10 parts of isobutyltrimethoxysilane in an aqueous medium with respect to 100 parts of the obtained toner particles. 1.0 part, and
It was produced by coalescing a plurality of silica fine particles which had been treated with 10 parts of hexamethyldisilazane and had an average primary particle size of 60 mμm. BET specific surface area is 43m ² / g
Was added externally to obtain cyan toner 1. The cyan toner 1 was photographed under magnification with an electron microscope, and the physical properties and the number of external additives on the cyan toner 1 were examined. Table 1 shows the results.

The above-mentioned non-spherical silica fine particles were subjected to a surface treatment with 100 parts of commercially available silica fine particles # 50 (manufactured by Nippon Aerosil Co., Ltd.) with 10 parts of hexamethyldilarazane, and then compared with an air classifier. The coarse particles are sampled to adjust the particle size distribution. In the non-spherical silica fine particles, a plurality of primary particles having an average primary particle diameter of 60 mμm were united in a 100,000-fold enlarged photograph by a transmission electron microscope (TEM) and a 30,000-fold enlarged photograph by a scanning electron microscope (SEM). The particles were confirmed to be particles. The non-spherical silica fine particles had a shape as shown in FIG.

(Production Example 2 of Cyan Toner) Polyester resin obtained by condensing propoxylated bisphenol with fumaric acid and trimellitic acid 100 parts Phthalocyanine pigment 4 parts Aluminum compound of tert-butyl salicylic acid 4 parts Low molecular weight polypropylene 4 Department

The above raw materials are premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely ground to about 1 to 20 mm using a hammer mill, and then finely ground by an air jet method. Finely pulverized with a machine. Further, the obtained finely pulverized product was classified, and then subjected to a spheroidizing treatment by a mechanical impact with a hybridizer (manufactured by Nara Machinery Co., Ltd.) to obtain a weight average particle size of 6.3 μm, SF-1
Was obtained, and an external additive was added in the same manner as in Production Example 1 of cyan toner to obtain cyan toner 2. The cyan toner 2 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 3 of Cyan Toner) In Production Example 2 of cyan toner, two parts of hydrophobic titanium oxide were used.
Except that no non-spherical silica fine particles were used, toner particles 3 having a weight average particle diameter of 6.5 μm, SF-1 of 114 and SF-2 of 107 were obtained, and cyan toner 3 was obtained. The cyan toner 3 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 4 of Cyan Toner) The same procedure as in Production Example 2 of cyan toner was carried out except that 2 parts of non-spherical silica fine particles were used and no hydrophobic titanium oxide was used.
Weight average particle size 6.6 μm, SF-1 is 114, SF-2
107, and a cyan toner 4 was obtained. The cyan toner 4 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 5 of Cyan Toner) The titanium oxide used in Production Example 1 of cyan toner was treated with alumina and then treated with isobutyltrimethoxysilane, and the BET specific surface area was 88 m ² / g. Except for using a certain anatase-type titanium oxide (4 × 10 ¹¹ Ωcm), toner particles 5 were obtained in the same manner as in Production Example 1 of cyan toner, and cyan toner 5 was obtained.

The weight average particle size of the toner particles 5 is 6.1.
μm, SF-1 was 115 and SF-2 was 108.

The cyan toner 5 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 6 of Cyan Toner) In place of the non-spherical silica fine particles used in Production Example 1 of cyan toner, 100 centipoise dimethyl silicone oil 2 was used.
B produced by coalescing a plurality of silica fine particles which have been treated with 0 parts and have an average primary particle size of 70 mμm.
Except for using non-spherical silica fine particles having an ET specific surface area of 35 m ² / g, toner particles 6 were obtained in the same manner as in Production Example 1 of cyan toner, and cyan toner 6 was further obtained. The toner particles 6 have a weight average particle size of 6.1 μm and SF-1.
Was 115 and SF-2 was 107. Cyan toner 6
Was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 7 of Cyan Toner) The titanium oxide used in Production Example 1 of cyan toner was prepared by
30 m ² / g, and the weight average particle diameter was 6.5 μm, SF-1 was 114, and SF-2 was 10 in the same manner as in Production Example 1 of the cyan toner except that alumina fired at a low temperature was used.
8 was obtained, and a cyan toner 7 was produced. The cyan toner 7 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 8 of Cyan Toner) The titanium oxide used in Production Example 1 of cyan toner was prepared by
A 5 m ² / g, except for replacing the titanium oxide obtained by firing at a high temperature in the same manner as in Preparation Example 1 of cyan toner, the weight average particle diameter of 6.5 [mu] m, SF-1 is 114, SF-2 is 10
7 was obtained, and a cyan toner 8 was produced. The cyan toner 8 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 9 of Cyan Toner) The titanium oxide used in Production Example 1 of cyan toner was treated with 500 cp of silicone oil to have a BET specific surface area of 25 m ² / g.
In the same manner as in Production Example 1 of the cyan toner except that titanium oxide was used, the weight average particle size was 6.5 μm, and SF-1 was used.
Is 115 and SF-2 is 108 to obtain toner particles 9,
Further, a cyan toner 9 was produced. The cyan toner 9 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 10 of Cyan Toner) The titanium oxide used in Production Example 1 of cyan toner was treated with 3000 cp silicone oil, and the BET specific surface area was 70 m ^2.
/ G of 6.5 μm and SF in the same manner as in Production Example 1 of the cyan toner except that titanium oxide was used.
-1 is 115 and SF-2 is 107
Was obtained, and a cyan toner 10 was produced. The cyan toner 10 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 11 of Cyan Toner) A non-spherical silica fine particle having a BET specific surface area of 100 m ² / g and treated with 5 parts of hexamethyldisilazane was used for the non-spherical silica fine particles used in Production Example 1 of cyan toner. A toner particle 11 having a weight average particle size of 6.5 μm, SF-1 of 115 and SF-2 of 108 was obtained in the same manner as in the production example 1 of the cyan toner except that the toner was replaced with fine particles. did. The cyan toner 11 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 12 of Cyan Toner) The non-spherical silica fine particles used in Production Example 1 of cyan toner were converted into non-spherical silica fine particles having a BET specific surface area of 20 m ² / g and treated with 3000 cp of silicon oil. Except for changing, in the same manner as in Production Example 1 of cyan toner, toner particles 12 having a weight-average particle diameter of 6.5 μm, SF-1 of 115 and SF-2 of 108 were obtained, and further, cyan toner 12 was produced. The cyan toner 12 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 13 of Cyan Toner) The non-spherical silica fine particles used in Production Example 1 of the cyan toner were prepared by mixing 10 parts of hexamethyldisilazane with 10 parts of dimethyl silicone oil having a BET specific surface area of 30 m ² / g and 100 cp. In the same manner as in Production Example 1 of the cyan toner, except that the non-spherical silica fine particles treated in part were used, the weight average particle diameter was 6.5.
The toner particles 13 having μm, 115 of SF-1 and 107 of SF-2 were obtained, and a cyan toner 13 was produced. The cyan toner 13 was observed with an electron microscope.
Shown in

(Production Example 14 of Cyan Toner) Except that the non-spherical silica fine particles used in Production Example 1 of cyan toner were pulverized by a jet mill and replaced with non-spherical silica fine particles having a BET specific surface area of 46 m ² / g. In the same manner as in Production Example 1 of the cyan toner, the weight average particle diameter was 6.5 μm, and SF-1 was used.
Was 114 and SF-2 was 107, and a cyan toner 14 was produced. Cyan toner 1
4 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 15 of Cyan Toner) A weight average particle size is 9.5 μm, SF-1 is 145, and S
Toner particles 15 having an F-2 of 160 were obtained, and a cyan toner 15 was produced. Average particle size of external additive, SF-1,
The abundance was the same as that of Production Example 2 of the cyan toner.

(Production Example 16 of Cyan Toner) The same procedure as in Production Example 1 of cyan toner was carried out except that the addition amount of titanium oxide was changed to 0.02 parts in Production Example 1 of cyan toner, and the weight average particle diameter was 6. 5 μm, SF-1 is 115, SF-2
Was 107, and a cyan toner 16 was produced. The cyan toner 16 was observed with an electron microscope, and the results are shown in Table 1.

(Production Example 17 of Cyan Toner) The same procedure as in Production Example 1 of cyan toner was carried out except that the addition amount of the non-spherical silica fine particles was changed to 2.5 parts in Production Example 1 of cyan toner. 6.5 μm, SF-1 is 116,
Toner particles 17 having SF-2 of 108 were obtained, and cyan toner 17 was produced. The cyan toner 17 was observed with an electron microscope, and the results are shown in Table 1.

[0264]

[Table 1]

(Production Example 1 of Carrier for Development) Phenol / formaldehyde monomer (50:50) in an aqueous medium
After mixing and dispersing, magnetic powder 6 obtained by subjecting magnetite particles surface-treated with alumina to hydrophobic treatment with isopropoxytriisostearoyl titanate with respect to the monomer weight.
00 parts, 400 parts of non-magnetic hematite particles hydrophobized with isopropoxytriisostearoyl titanate are uniformly dispersed, and while appropriately adding ammonia, a monomer is polymerized to form a spherical magnetic resin carrier core material containing magnetic particles. I got

On the other hand, toluene 20 parts, butanol 20
, 20 parts of water and 40 parts of ice were placed in a four-necked flask, and while stirring, 40 parts of a mixture of CH ₃ SiCl ₃ and (CH ₃ ) ₂ SiCl ₂ in a molar ratio of 3: 2 and a catalyst were added, and the mixture was further added with 30 parts. After stirring for minutes, a condensation reaction was performed at 60 ° C. for 1 hour. Thereafter, the siloxane was sufficiently washed with water and dissolved in a toluene-methylethylketone-butanol mixed catalyst to prepare a silicone varnish having a solid content of 10%.

The silicone varnish was prepared by adding 2.0 parts of ion-exchanged water to 100 parts of siloxane solids and 2.
0 parts of the following curing agent

[0268]

[Outside 4] And 2 parts of the following aminosilane coupling agent

[0269]

[Outside 5] Was added simultaneously to prepare a carrier coating solution I.

This solution I was applied to 100 parts of the above-mentioned carrier core material using a coating machine (Spiracoater, manufactured by Okada Seiko Co., Ltd.) so that the resin coating amount was 1 part, to obtain carrier I for development.

This carrier has a volume resistance of 4 × 10 ¹³
Ωcm, σ ₁₀₀₀ is 37 Am ² / kg, coercive force is 55 Oe, weight average particle size is 34 μm, SF-1 is 11
5, SF-2 was 108.

(Development Carrier Production Example 2) The non-spherical silica fine particles used in the cyan toner production example 1 were added to the development carrier I in an amount of 0.0
Two parts were added and mixed to obtain a developing carrier II.

The carrier II for development had the same volume resistance value, magnetic properties, weight average particle size, SF-1 and SF-2 as the carrier I for development.

When the surface of the carrier II for development was observed under an electron microscope, the average particle diameter of the non-spherical silica fine particles was 190 μm, the major axis / minor axis was 3.2, and the ratio of SF-1 was 155.

(Production Example 3 of Developing Carrier) In Production Example 2 of developing carrier, 100 parts of magnetite were used instead of 600 parts of magnetic powder and 400 parts of nonmagnetic hematite particles.
Parts, and the amount of non-spherical silica
A developing carrier III was obtained in the same manner as in Production Example 2 of the developing carrier, except for using a part.

The developing carrier III has a volume resistance of 5 ×
10 ¹¹ Ωcm, σ ₁₀₀₀ is 61 Am ² / kg, coercive force is 7
7 Oersted, the weight average particle diameter was 33 μm, SF-1 was 119, and SF-2 was 110.

When the surface of the developing carrier III was enlarged and observed with an electron microscope, the average particle diameter of the non-spherical silica fine particles was 190 μm, the long diameter / short diameter was 3.2, and the SF-
1 was 155.

(Production Example 4 of Developing Carrier) In Production Example 2 of developing carrier, except that 0.02 parts of the titanium oxide fine particles used in Production Example 1 of cyan toner were added instead of the non-spherical silica fine particles. A developing carrier IV was obtained in the same manner as in Production Example 2 of the developing carrier.

The carrier IV for development had the same volume resistance, magnetic properties, weight average particle size, SF-1 and SF-2 as the carrier I for development.

When the surface of the developing carrier IV was enlarged and observed with an electron microscope, the average particle diameter of the titanium oxide fine particles was 50 μm, the major axis / minor axis was 1.1, and SF-1 was 12 μm.
It was one.

(Production Example 5 of Developing Carrier) Styrene-methyl methacrylate (70:30) copolymer 30 parts Magnetite (EPT-1000: manufactured by Toda Kogyo Co., Ltd.) 100 parts The above components were melt-kneaded with a pressure kneader. Further, using a turbo mill and a classifier, pulverization and classification were performed. To this, 0.01 part of the non-spherical silica fine particles used in Production Example 1 of the cyan toner were added and mixed. Obtained. The carrier V for development has a volume resistance of 4 × 10 ⁹ Ωc.
m, σ ₁₀₀₀ is 57 Am ² / kg, coercive force is 85 Oersted, weight average particle size is 37 μm, SF-1 is 145, S
F-2 was 135.

When the surface of the developing carrier V was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190 μm.
m, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 6 of Developing Carrier) In Production Example 1 of developing carrier, CH ₃ SiCl ₃ and (CH
Instead of the mixture 40 parts of _{3) 2} SiCl _2, vinylidene fluoride - tetrafluoroethylene copolymer / styrene - except using methyl methacrylate copolymer (50:50), the development carrier Production Example 1 In the same manner as in the above, a development carrier VI was obtained.

The volume resistance of the developer carrier VI is
7 × 10 ¹³ Ωcm, σ ₁₀₀₀ is 37 Am ² / kg, coercive force is 55 Oersted, weight average particle size is 34 μm, SF−
1 was 115 and SF-2 was 109.

(Production Example 7 of Developing Carrier) In Production Example 2 of the developing carrier, except that the polymerization conditions were changed, the volume resistivity was 8 × 10 ¹³ Ωcm in the same manner as in Production Example 2 of the developing carrier. , ₁₀₀₀ is 37 Am ² / kg, coercive force is 45 Oersted, weight average particle size is 55 μm, S
A developing carrier VII having F-1 of 114 and SF-2 of 107 was obtained.

When the surface of the developing carrier VII was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190.
m μm, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 8 of Developing Carrier) A volume resistance value of 7 × 10 ¹² Ωcm was obtained in the same manner as in Production Example 2 of the developing carrier, except that polymerization conditions were changed. , Σ ₁₀₀₀ is 37 Am ² / kg, coercive force is 75 Oersted, weight average particle size is 18 μm, S
A developing carrier VIII having F-1 of 120 and SF-2 of 118 was obtained.

When the surface of the developing carrier VIII was observed with a microscope, the average particle size of the non-spherical silica fine particles was 19
0 μm, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 9 of Developing Carrier) In Production Example 2 of the developing carrier, except that the polymerization conditions were changed, the volume resistivity was 1 × 10 ¹⁴ Ωcm in the same manner as in Production Example 2 of the developing carrier. Σ ₁₀₀₀ is 37 Am ² / kg, coercive force is 40 Oe, weight average particle size is 65 μm, S
A development carrier IX having F-1 of 114 and SF-2 of 107 was obtained.

When the surface of the developing carrier IX was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190 m.
μm, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 10 of Developing Carrier) A volume resistivity value of 5 × 10 ¹⁰ Ωcm was obtained in the same manner as in Production Example 2 of the developing carrier, except that polymerization conditions were changed. Σ ₁₀₀₀ is 37 Am ² / kg, coercive force is 90 Oersted, weight average particle size is 13 μm, S
A developing carrier X in which F-1 was 127 and SF-2 was 125 was obtained.

When the surface of the developing carrier X was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190 μm.
m, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 11 of Developing Carrier) In Production Example 2 of the developing carrier, except that magnetite particles not subjected to hydrophobic treatment were used, the volume resistivity was 7 in the same manner as in Production Example 2 of the developing carrier. × 10 ⁷ Ωcm, σ
₁₀₀₀ 37Am ² / kg, a coercive force of 50 Oe,
Weight average particle size is 35 μm, SF-1 is 135, SF-2
Of 145 was obtained.

When the surface of the developing carrier XI was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190 m.
μm, major axis / minor axis was 3.2, and SF-1 was 155.

(Manufacturing Example 12 of Developing Carrier) In the same manner as in Manufacturing Example 2 of the developing carrier, except that the amount of the resin coat was changed to 4 parts by changing the conditions of the carrier coating in the manufacturing example 2 of the developing carrier. And the volume resistance value is 2 × 10
¹⁵ Ωcm, σ ₁₀₀₀ is 33 Am ² / kg, coercive force is 40 Oersted, weight average particle size is 35 μm, SF-1 is 12
0, and a developing carrier XII having SF-2 of 110 was obtained.

When the surface of the developing carrier XII was observed with a microscope, the average particle size of the non-spherical silica fine particles was 190.
m μm, major axis / minor axis was 3.2, and SF-1 was 155.

(Production Example 13 of Developing Carrier) In Production Example 2 of developing carrier, except that 600 parts of Mg—Mn—Fe ferrite fine particles were used instead of 600 parts of magnetic powder, As in Production Example 2, the volume resistivity was 8 × 10 ¹² Ωcm and σ ₁₀₀₀ was 39.
A developing carrier XIII having Am ² / kg, a coercive force of 7 Oersted, a weight average particle size of 32 μm, SF-1 of 118 and SF-2 of 110 was obtained.

When the surface of the developing carrier XIII was observed with a microscope, the average particle size of the non-spherical silica fine particles was 19
0 μm, major axis / minor axis was 3.2, and SF-1 was 155.

[0299]

[Table 2]

(Example of manufacturing magnetic particles for charging) 5 parts of MgO,
After 8 parts of MnO, 4 parts of SrO and 83 parts of Fe ₂ O ₃ were each atomized, water was added and mixed, and the mixture was granulated.
After baking at ℃ and adjusting the particle size, a ferrite core material having an average particle size of 28 μm (σ ₁₀₀₀ of 60 Am ² / kg, coercive force of 55 Oersted) was obtained.

To the above carrier core material, 10 parts of isopropoxytriisostearoyl titanate was added in an amount of 99 parts of hexane.
One part mixed with water was subjected to a surface treatment so as to be 0.1 part to obtain magnetic particles a.

The magnetic particles have a volume resistance of 3 × 10 ⁷ Ω.
cm, and the weight loss on heating was 0.1 part.

(Production Example of Photoconductor) The photoconductor (latent image carrier) is a photoconductor using an organic photoconductive material for negative charging, and the functional layer is formed on an aluminum cylinder having a diameter of 30 mm.
Layers are provided.

The first layer is a conductive particle-dispersed resin layer having a thickness of about 20 μm, which is provided to smooth defects of the aluminum cylinder and to prevent the occurrence of moire due to reflection by laser exposure. It is.

The second layer is a positive charge injection preventing layer (undercoat layer), which serves to prevent positive charges injected from the aluminum substrate from canceling negative charges charged on the surface of the photoreceptor. This is a medium resistance layer having a thickness of about 1 μm, the resistance of which is adjusted to about 10 ⁶ Ωcm by 66-610-12-nylon and methoxymethylated nylon.

The third layer is a charge generation layer, and is a layer having a thickness of about 0.3 μm in which a disazo pigment is dispersed in a resin, and generates positive and negative charge pairs by being exposed to a laser.

The fourth layer is a charge transport layer, in which hydrazone is dispersed in a polycarbonate resin, and is a P-type semiconductor. Therefore, the negative charges charged on the photoreceptor surface cannot move through this layer, and only the positive charges generated in the charge generation layer can be transported to the photoreceptor surface.

The fifth layer is a charge injecting layer, which is made of a photo-curable acrylic resin and ultrafine SnO ₂ particles, and further increases the contact time between the charging member and the photoreceptor to achieve uniform charging. It is a dispersion of 0.25 μm tetrafluoroethylene resin particles. Specifically, oxygen-deficient SnO ₂ particles having a reduced resistance and a particle diameter of about 0.03 μm are added to the resin by 1%.
60% by weight, 30% by weight of tetrafluoroethylene resin particles and 1.2% by weight of a dispersant.

As a result, the volume resistivity of the surface layer of the photoreceptor 1 was reduced to 6 × 10 ¹¹ Ωcm, compared with 5 × 10 ¹⁵ Ωcm for the charge transport layer alone.

Example 1 A cyan toner 1 and a developing carrier II were combined with a toner having a toner density of 8
The mixture was mixed by weight% to prepare a cyan developer (compression degree: 11%, apparent density: 1.47 g / cm ³ ).

Next, the developing and charging device of a commercially available copying machine GP55 (manufactured by Canon) was modified as shown in FIG. 1, and magnetic particles a were used as the charging member, and the photosensitive member 1 was exposed in the counter direction. By rotating at a peripheral speed of 120% of the peripheral speed of the body, a DC / AC electric field (-700 V, 1 kHz /
1.2 kV _pp ) was applied thereto, and the photoconductor 1 was charged.
Development is performed using the cyan developer and cyan toner 1 described above using the AC electric field shown in FIG.
The unfixed toner image transferred onto the transfer material is shown in FIG.
Was fixed to the transfer material by a pressure heating roller (not shown). Further, the cleaning of the photoreceptor was performed by a simultaneous development cleaning method in which the transfer residual toner was collected and reused simultaneously with the development in the development process. The toner concentration in the developer was set to maintain 8% by weight. Under an environment of 23 ° C./65% under the above-mentioned conditions, 2000 original sheets with an image area ratio of 20% are continuously copied, and then original development with an image area ratio of 6% is performed.
Copies. After that, a document with an image area ratio of 20% and 6%
Were alternately copied, and continuous copying was performed until the total number reached 30,000. During continuous copying, the toner density is measured every 2500 sheets, and the bulk density of the developer is measured at the initial stage, at 15,000 sheets and at the end of 30,000 sheets, and the image density, fog and solid density unevenness of the copied image are measured. An evaluation was performed. FIG. 5 shows a change in toner density in 30,000 copies.

Table 3 shows the measurement results of the bulk density and other evaluation results. From Table 3, it can be seen that the toner density is controlled stably and a good image is stably obtained over a long period of time. Further, it can be seen that the toner is reused without any problem.

Example 2 The procedure of Example 1 was repeated, except that the developing carrier I was used, and the degree of compression was 16% and the apparent density was 1.47 g / cm.
^When the image was produced using the developer of No. ³ , when the original document having an image area ratio of 6% was copied, the toner density was lowered and the image density was slightly lowered, but a good image was obtained.

This is presumably because no additive was added to the carrier in advance, so that the bulk density of the developer was lower than that of the first embodiment in the original document of low consumption, and the toner supply amount was suppressed. You. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 3 In Example 1, the cyan toner 2 was used, and the compression degree was 1.
When the image was produced in the same manner except that the developer was 9% and the apparent density was 1.43 g / cm ³ , the image density was slightly increased and the fog suppression was slightly reduced when a 20% original document was used. However, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 1 In Example 3, the cyan toner 3 was used, and the compression degree 2
An image was formed in the same manner except that the developer was 0% and the apparent density was 1.38 g / cm ^{3. When} the original of 6% was used, the image density decreased and fog increased. 50,000 copies were canceled. This is because the non-spherical silica fine particles were not used as the external additive of the toner, so that the titanium oxide of the external additive in the toner was embedded in the toner when the original document with low consumption was used.
It is presumed that the developability of the toner deteriorated, and at the same time, the bulk density of the developer became small and the toner supply amount was suppressed. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 2 In Example 3, the cyan toner 4 was used, and the degree of compression was 2
When image formation was performed in the same manner except that the apparent density was set to 1% and the apparent density was set to 1.39 g / cm ³ , when using a 20% original document, image density unevenness became worse and fog increased. . This is because, because the external additive of the toner is only non-spherical silica fine particles, uniform mixing of the replenishment toner is not achieved when using the original document that consumes a large amount, and as a result, the control of the toner concentration becomes unstable. It is presumed that it was. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 4 An image was formed in the same manner as in Example 1 except that the developing carrier III was used and the degree of compression was 12% and the apparent density was 1.51 g / cm ^3. %, The image density slightly decreased when the original was used, but good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

This is presumed to be due to the fact that the magnetic properties of the carrier were enhanced, and the toner damage was slightly increased in the original document with low consumption.

Example 5 Image formation was carried out in the same manner as in Example 1 except that the developing carrier IV was used and the degree of compression was 12% and the apparent density was 1.48. Good results were obtained. Was done. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 3 An image was formed in the same manner as in Example 1 except that the developing carrier V was used and the degree of compression was 25% and the apparent density was 1.27 g / cm ^3. The density control was not successful, and the evaluation was stopped after 5,000 sheets. This is presumed to be because the change in bulk density was too large because the shape of the carrier was non-spherical. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 6 An image was formed in the same manner as in Example 1 except that the developing carrier VI was used and the degree of compression was 14% and the apparent density was 1.51. Good results were obtained although fog was noticeable. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 7 The same procedure as in Example 1 was carried out except that the developing sleeve was rotated in the same direction in the photosensitive drum and the developing section, but good results were obtained although solid density unevenness was slightly deteriorated. .

[0324] This is because the rotation of the developing sleeve made it difficult to balance the peeling of the developer after development and the surface coat of fresh developer, and the toner density control became somewhat unstable. It is presumed. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Embodiment 8 The same procedure as in Embodiment 1 was carried out except that the cyan toner 5 was used and the compression degree was 1.
When the same procedure was carried out except that the developer was 4% and the apparent density was 1.43 g / cm ³ , it is presumed that SF-1 of the titanium oxide was increased. And good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Embodiment 9 The same procedure as in Embodiment 1 was carried out except that the cyan toner 6 was used and the degree of compression was 1;
When the same procedure was performed except that the developer was 3% and the apparent density was 1.50 g / cm ³ , it was presumed that the SF-1 of the silica was reduced. Although the change in the image density was large, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 10 The same procedure as in Example 1 was carried out except that the cyan toner 7 was used and the compression degree was 1
An image was formed in the same manner except that a developer having a density of 3% and an apparent density of 1.43 g / cm ³ was used. Although density unevenness was recognized, a good image was obtained. Example 1
Table 3 shows the results of the same measurements and evaluations as described above.

Example 11 Image formation was performed in the same manner as in Example 1 except that a developer having a compression degree of 12% and an apparent density of 1.49 g / cm ³ was used using the cyan toner 8 and the developing carrier VII. As a result, the toner density was slightly lower than that in Example 1, and although the image density was slightly reduced, good results were obtained without solid density unevenness. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 12 Using cyan toner 9, the degree of compression was 13% and the apparent density was 1.
An image was formed in the same manner as in Example 11 except that the developer was used at 44 g / cm ^3. As a result, good results were obtained although fogging was slightly observed as compared with Example 11.
Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 4 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 13% and an apparent density of 1.41 g / cm ³ was used using cyan toner 10. Solid density unevenness became remarkable as compared with Example 11, and good results were not obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 5 An image was formed in the same manner as in Example 11 except that a cyan toner 11 was used as a developer having a compression degree of 18% and an apparent density of 1.50 g / cm ^3. The change in density was large, and good results were not obtained for both fog and solid density unevenness. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 13 An image was formed in the same manner as in Example 11 except that a cyan toner 12 was used and a developer having a compression degree of 11% and an apparent density of 1.39 g / cm ³ was used. Although fog and solid density unevenness slightly occurred as compared with Example 11, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 14 An image was formed in the same manner as in Example 11, except that a developer having a compression degree of 12% and an apparent density of 1.41 g / cm ³ was used using cyan toner 13. Good results were obtained although some fog was observed. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 6 An image was formed in the same manner as in Example 11 except that a cyan toner 14 was used and a developer having a compression degree of 20% and an apparent density of 1.52 g / cm ³ was used. The change in toner density was large, and the solid density unevenness became remarkable. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 15 An image was formed in the same manner as in Example 11 except that a cyan toner 15 was used and a developer having a compression degree of 13% and an apparent density of 1.52 g / cm ³ was used. Although the solid density unevenness was slightly reduced as compared with Example 11, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 16 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 14% and an apparent density of 1.42 g / cm ³ was used using cyan toner 16. Good results were obtained although fogging was slightly observed as compared with Example 11. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 17 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 11% and an apparent density of 1.43 g / cm ³ was used using cyan toner 17. Although the solid density unevenness was slightly reduced as compared with Example 11, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 18 Example 11 was repeated except that a developer having a compression degree of 15% and an apparent density of 1.47 g / cm ³ was used by using the developing carrier VIII.
When the image was formed in the same manner as in the above, the carrier was easily attached to the photoreceptor, and good results were obtained although some fogging occurred. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Comparative Example 7 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 13% and an apparent density of 1.52 g / cm ³ was used using the developing carrier IX. Both fog and solid density unevenness became remarkable as compared with Example 11. Example 1
Table 3 shows the results of the same measurements and evaluations as described above.

Comparative Example 8 Using the developing carrier X, the degree of compression was 17% and the apparent density was 1.
An image was formed in the same manner as in Example 11 except that the amount of the developer was changed to 42 g / cm ³ , and the image formation was stopped because a large amount of carrier adhered to the photoreceptor. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 19 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 12% and an apparent density of 1.46 g / cm ³ was used by using a developing carrier XI. As compared with Example 11, both fog and solid density unevenness were slightly reduced, but good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 20 An image was formed in the same manner as in Example 11 except that a developer having a compression degree of 13% and an apparent density of 1.45 g / cm ³ was used using the developing carrier XII. Good results were obtained although the image density was slightly lower than in Example 11. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 21 Example 11 was repeated except that a developer having a compression degree of 12% and an apparent density of 1.52 g / cm ³ was used using the developing carrier XIII.
In the same manner as in the above, when an image was formed, good results were obtained. Table 3 shows the results of the same measurements and evaluations as in Example 1.

Example 22 A yellow developer, a magenta developer and a black developer were prepared in the same manner as in Example 1 except that the colorant was changed in the cyan developer. The three-color developer,
When the cyan developer used in Example 1 was used in an image forming apparatus having a configuration shown in FIG. 3 and 30,000 sheets of image were formed in the order of yellow, magenta, cyan, and black, the image density changed. A good image with small fog was suppressed.

[0345]

[Table 3]

The evaluation methods in Examples and Comparative Examples are shown below.

(1) Bulk Density The bulk density of the developer was determined according to the measurement of apparent density.

(2) Image Density An original manuscript provided with a circle having a diameter of 20 mm and having an image density of 1.5 as measured by a reflection densitometer RD918 (manufactured by Macbeth) is copied, and the image density of the image portion is determined by the reflection density. Total RD
918.

(3) Fog Measurement of fog was performed using REFLECTOME manufactured by Tokyo Denshoku Co., Ltd.
TER MODELTC-6DS was used using an amber filter, and fog was calculated from the following equation.

Fog (%) = Reflectance of standard paper (%) − Reflectance of non-image portion of copied image (%)

(4) Solid density unevenness An original manuscript having five circles each having a diameter of 20 mm and having an image density of 1.50 measured by a reflection densitometer RD918 (manufactured by Macbeth) was copied, and the image density of the image portion was copied. Was measured with a reflection densitometer RD918, and the difference between the maximum value and the minimum value at that time was determined.

[0352]

According to the present invention, there is provided an image forming apparatus having means for controlling the toner concentration by detecting the change in the magnetic permeability of the developer by using the inductance of the coil to determine the mixture ratio of the toner and the carrier of the developer. By using a toner having two types of external additives, spherical and non-spherical, and using a magnetic powder-dispersed spherical carrier, the change in bulk density of the developer can be reduced, and accurate toner density control can be performed. A low-cost and compact image forming apparatus capable of obtaining a high-quality image during durability is achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a preferred example of an image forming apparatus according to the present invention.

FIG. 2 is a diagram showing an alternating electric field used in Example 1.

FIG. 3 is a schematic view illustrating another example of the image forming apparatus of the present invention.

FIG. 4 is a schematic diagram of a cell used for measuring a volume resistance value.

FIG. 5 is a diagram illustrating a change in toner density according to the first exemplary embodiment.

FIG. 6 is a schematic view showing the particle shape of non-spherical inorganic oxide fine particles.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 latent image carrier (photosensitive drum) 4 developing container 11 developer carrier (developing sleeve) 12 magnet roller 13, 14 developer transport screw 15 regulating blade 17 partition 18 replenishing toner 19 developer 19 a toner 19 b carrier 20 replenishing port Reference Signs List 21 magnet roller 22 transfer sleeve 23 magnetic particles 24 laser beam 25 transfer material 26 bias applying means 27 transfer blade 28 toner concentration detection sensor 31 lower electrode 32 upper electrode 33 sample 34 insulator 61a photosensitive drum 62a primary charger 63a developing device 64a transfer Blade 65a Replenishing toner 67a Laser beam 68 Transfer material carrier 69 Separator charger 70 Fixing device 71 Fixing roller 72 Pressure roller 73 Webs 75, 76 Heating means 79 Transfer belt cleaning device 80 Drive Roller 81 belt driven roller 82 belt discharger 83 registration rollers 85 toner concentration detecting sensor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 9/107 G03G 9/08 375 9/113 384 15/09 9/10 331 352 354 (72) Inventor Masanori Shida 3 Shimomaruko, Ota-ku, Tokyo Within Chome 30-2 Canon Inc.

Claims (80)

[Claims] A charging step of charging the latent image carrier; a latent image forming step of forming an electrostatic latent image on the charged latent image carrier; A developing step of developing an electrostatic latent image by a developing unit having a developer carrier for carrying and transporting the component-based developer and a magnetic field generator fixed inside the developer carrier; a coil; Controlling the toner concentration by detecting a change in the magnetic permeability of the two-component developer using the inductance of the two-component developer, wherein the two-component developer contains at least a magnetic powder in the binder resin. And a non-magnetic toner in which an external additive is attached to the surface of the non-magnetic toner particles. The spherical magnetic powder-dispersed carrier has a weight average particle size. 15 ~
60 μm, the non-magnetic toner particles have a weight average particle diameter of 2 to 9 μm, the external additive is present as primary particles or secondary particles on the toner particles, and the shape factor SF-1 is 100 μm. ~ 130
And a non-spherical inorganic oxide fine particle (B) having a shape factor SF-1 of more than 150, which is produced by coalescing a plurality of particles. Image forming method. 2. The image forming method according to claim 1, wherein the inorganic oxide fine particles (A) have an average particle size of 10 to 400 μm. 3. The inorganic oxide fine particles (A) have an average particle size of:
The image forming method according to claim 1, wherein the thickness is 15 to 200 μm. 4. The image forming method according to claim 1, wherein said inorganic oxide fine particles (A) have an average particle size of 15 to 100 μm. 5. The image forming method according to claim 1, wherein the non-spherical inorganic oxide fine particles (B) have an average particle size of 120 to 600 μm. 6. The surface of the non-magnetic toner particles, wherein the inorganic oxide fine particles (A) are observed by an electron microscope enlarged photograph.
The image forming method according to any one of claims 1 to 5, wherein 5 or more are present per 5 µm x 0.5 µm area. 7. The surface of the non-magnetic toner particles whose inorganic oxide fine particles (A) are observed by an electron microscope enlarged photograph.
The image forming method according to any one of claims 1 to 5, wherein 7 or more are present per 5 µm x 0.5 µm area. 8. The surface of the non-magnetic toner particles whose inorganic oxide fine particles (A) have a particle diameter of 0.1 nm as observed by an electron microscope enlarged photograph.
The image forming method according to any one of claims 1 to 5, wherein 10 or more are present in an area of 5 µm x 0.5 µm. 9. Non-spherical inorganic oxide fine particles (B) are present in an amount of 1 to 30 per 1.0 μm × 1.0 μm area of the surface of the non-magnetic toner particles observed by an electron microscope enlarged photograph. The image forming method according to claim 1, wherein: 10. The non-spherical inorganic oxide fine particles (B),
The image according to any one of claims 1 to 8, wherein 1 to 25 particles are present per area of 1.0 µm x 1.0 µm of the surface of the nonmagnetic toner particles observed by an electron microscope enlarged photograph. Forming method. 11. The non-spherical inorganic oxide fine particles (B)
The image according to any one of claims 1 to 8, wherein 5 to 25 particles are present per area of 1.0 µm x 1.0 µm of the surface of the nonmagnetic toner particles observed by an electron microscope enlarged photograph. Forming method. 12. The non-magnetic toner according to claim 10, wherein the non-magnetic toner is a non-magnetic toner.
12. The composition according to claim 1, further comprising 0.1 to 2 parts by weight of the inorganic oxide fine particles (A) based on 0 part by weight.
The image forming method according to any one of the above. 13. The non-magnetic toner according to claim 1, wherein the non-magnetic toner is a non-magnetic toner.
The inorganic oxide fine particles (A) are present in an amount of 0.2 to 2 parts by weight with respect to 0 parts by weight.
The image forming method according to any one of the above. 14. The non-magnetic toner according to claim 1, wherein the non-magnetic toner is a non-magnetic toner.
The image forming method according to any one of claims 1 to 11, comprising 0.2 to 1.5 parts by weight of the inorganic oxide fine particles (A) based on 0 part by weight. 15. The non-magnetic toner according to claim 1, wherein the non-magnetic toner is a non-magnetic toner.
The image forming method according to any one of claims 1 to 14, further comprising 0.3 to 3 parts by weight of the non-spherical inorganic oxide fine particles (B) based on 0 part by weight. 16. The non-magnetic toner according to claim 1, wherein the non-magnetic toner is a non-magnetic toner.
The image forming method according to any one of claims 1 to 14, further comprising 0.3 to 2.5 parts by weight of the non-spherical inorganic oxide fine particles (B) based on 0 part by weight. 17. The method according to claim 17, wherein the non-magnetic toner is a non-magnetic toner.
The image forming method according to any one of claims 1 to 14, further comprising 0.3 to 2 parts by weight of the non-spherical inorganic oxide fine particles (B) based on 0 part by weight. 18. The method according to claim 18, wherein the non-magnetic toner is a non-magnetic toner.
The image forming method according to any one of claims 1 to 14, further comprising 0.3 to 1.5 parts by weight of the non-spherical inorganic oxide fine particles (B) per 0 parts by weight. 19. The method according to claim 1, wherein the inorganic oxide fine particles (A) have at least one inorganic oxide selected from the group consisting of titanium oxide and alumina.
19. The image forming method according to any one of the above items. 20. The non-spherical inorganic oxide fine particles (B)
20. The image forming method according to claim 1, wherein the image forming method is silica. 21. The image forming method according to claim 1, wherein the inorganic oxide fine particles (A) have a BET specific surface area of 60 to 230 m ² / g. 22. B of the non-spherical inorganic oxide fine particles (B)
ET specific surface area, the image forming method according to any one of claims 1 to 21, characterized in that the 20~90m ² / g. 23. The method according to claim 1, wherein at least a part of the spherical magnetic powder-dispersed carrier is mixed with at least one external additive before being mixed with the non-magnetic toner. An image forming method according to any one of the above. 24. The spherical magnetic powder-dispersed carrier is produced by a polymerization method.
The image forming method according to any one of the above. 25. The image forming method according to claim 1, wherein the spherical magnetic powder-dispersed carrier contains a phenol resin as a binder resin. 26. The image forming method according to claim 1, wherein the spherical magnetic powder-dispersed carrier has a nonmagnetic metal oxide. 27. The carrier according to claim 1, wherein the spherical magnetic powder-dispersed carrier is a carrier whose surface is coated with a resin using resin particles in which magnetic powder is dispersed as carrier core particles. The image forming method according to any one of the above. 28. The method according to claim 27, wherein the resin for coating the surface of the carrier core material particles is a silicone resin, a fluororesin, or a copolymer or a mixture of a fluororesin and an acrylic resin. Image forming method. 29. The image forming method according to claim 1, wherein the spherical magnetic powder-dispersed carrier has a weight average particle diameter of 20 to 60 μm. 30. The image forming method according to claim 1, wherein the spherical magnetic powder-dispersed carrier has a shape factor SF-1 of 100 to 140. 31. The image forming method according to claim 1, wherein the spherical magnetic powder-dispersed carrier has a volume resistance of 10 ⁹ to 10 ¹⁵ Ωcm. 32. The method according to claim 1, wherein the non-magnetic toner particles are toner particles produced by a polymerization method.
32. The image forming method according to any one of the above items. 33. The image forming method according to claim 32, wherein the non-magnetic toner particles have a core / shell structure. 34. The shape factor SF- of the nonmagnetic toner particles
2. The method according to claim 1, wherein 1 is 100 to 140.
34. The image forming method according to any one of the above items. 35. The shape factor SF- of the nonmagnetic toner particles
2 is 100-120.
35. The image forming method according to any one of items 34 to 34. 36. The non-magnetic toner particle according to claim 1, wherein the weight average particle diameter is 3 to 9 μm.
5. The image forming method according to any one of 5. 37. An apparent density of the two-component developer,
37. The image forming method according to claim 1, wherein the amount is 1.2 to 2.0 g / cm < ³ >. 38. The compression degree of the two-component developer is 5 to 1
The image forming method according to any one of claims 1 to 37, wherein the amount is 9%. 39. A developing device according to claim 1, wherein a developer regulating blade for regulating a layer thickness of the two-component developer carried by the developer carrying member is disposed below the developer carrying member.
39. The image forming method according to any one of the above items. 40. The image forming method according to claim 1, wherein said charging means is a magnetic brush charging. 41. A latent image carrier for carrying an electrostatic latent image; a charging means for charging the latent image carrier; and forming an electrostatic latent image on the charged latent image carrier. Image forming means for developing the electrostatic latent image; a developer carrier for carrying and transporting a two-component developer opposed to the latent image carrier; and an inside of the developer carrier. An image having a magnetic field generator fixed to the image forming apparatus; a toner density control means for controlling the toner density by detecting a change in the magnetic permeability of the two-component developer using the inductance of the coil; In the forming apparatus, the two-component developer includes a spherical magnetic powder-dispersed carrier in which at least magnetic powder is dispersed in a binder resin, and a non-magnetic toner in which an external additive is attached to the surface of non-magnetic toner particles. The spherical magnetic powder-dispersed carrier has a weight-average The particle size is 15 to
60 μm, the non-magnetic toner particles have a weight average particle diameter of 2 to 9 μm, the external additive is present as primary particles or secondary particles on the toner particles, and the shape factor SF-1 is 100 μm. ~ 130
And a non-spherical inorganic oxide fine particle (B) having a shape factor SF-1 of more than 150, which is produced by coalescing a plurality of particles. Image forming apparatus. 42. The image forming apparatus according to claim 41, wherein the inorganic oxide fine particles (A) have an average particle size of 10 to 400 μm. 43. The image forming apparatus according to claim 41, wherein the average particle size of the primary particles of the inorganic oxide fine particles (A) is 15 to 200 μm. 44. The image forming apparatus according to claim 41, wherein primary particles of the inorganic oxide fine particles (A) have an average particle size of 15 to 100 μm. 45. The image forming apparatus according to claim 41, wherein the non-spherical inorganic oxide fine particles (B) have an average particle size of 120 to 600 μm. 46. The method according to claim 46, wherein the inorganic oxide fine particles (A) are present in an amount of 5 or more per 0.5 μm × 0.5 μm area of the surface of the nonmagnetic toner particles observed by an electron micrograph. The image forming apparatus according to any one of claims 41 to 45. 47. The method according to claim 17, wherein the inorganic oxide fine particles (A) are present in an amount of 7 or more per 0.5 μm × 0.5 μm area of the surface of the nonmagnetic toner particles observed by an electron microscope enlarged photograph. The image forming apparatus according to any one of claims 41 to 45. 48. The method according to claim 1, wherein the inorganic oxide fine particles (A) are present in an amount of 10 or more per 0.5 μm × 0.5 μm area of the surface of the non-magnetic toner particles observed by an electron microscope enlarged photograph. The image forming apparatus according to any one of claims 41 to 45. 49. The non-spherical inorganic oxide secondary particles (B)
Are 1 to 3 per 1.0 μm × 1.0 μm area of the surface of the non-magnetic toner particles observed by an electron microscope enlarged photograph.
49. There are 0 pieces.
The image forming apparatus according to any one of the above. 50. The non-spherical inorganic oxide fine particles (B)
The image according to any one of claims 41 to 48, wherein 1 to 25 particles are present per area of 1.0 µm × 1.0 µm of the surface of the nonmagnetic toner particles observed by an electron microscope enlarged photograph. Forming equipment. 51. The non-spherical inorganic oxide fine particles (B)
The image according to any one of claims 41 to 48, wherein 5 to 25 particles are present per area of 1.0 µm x 1.0 µm of nonmagnetic toner particles observed by an electron micrograph. Forming equipment. 52. The method according to claim 52, wherein the non-magnetic toner is a non-magnetic toner.
The inorganic oxide fine particles (A) are contained in an amount of 0.1 to 2 parts by weight based on 0 parts by weight.
2. The image forming apparatus according to claim 1, 53. The method according to claim 53, wherein the non-magnetic toner is a non-magnetic toner.
The inorganic oxide fine particles (A) are present in an amount of 0.2 to 2 parts by weight with respect to 0 parts by weight.
2. The image forming apparatus according to claim 1, 54. The non-magnetic toner according to claim 50, wherein
The image forming apparatus according to any one of claims 41 to 51, further comprising 0.2 to 1.5 parts by weight of the inorganic oxide fine particles (A) based on 0 part by weight. 55. The method according to claim 55, wherein the non-magnetic toner is a non-magnetic toner.
42. The composition according to claim 41, further comprising 0.3 to 3 parts by weight of the non-spherical inorganic oxide fine particles (B) per 0 parts by weight.
55. The image forming apparatus according to any one of items 54 to 54. 56. The non-magnetic toner, wherein the non-magnetic toner is
The image forming apparatus according to any one of claims 41 to 54, further comprising 0.3 to 2.5 parts by weight of the non-spherical inorganic oxide fine particles (B) based on 0 part by weight. 57. The non-magnetic toner, wherein the non-magnetic toner is
42. The composition according to claim 41, comprising 0.3 to 2 parts by weight of the non-spherical inorganic oxide fine particles (B) per 0 parts by weight.
55. The image forming apparatus according to any one of items 54 to 54. 58. The non-magnetic toner, wherein the non-magnetic toner is
The image forming apparatus according to any one of claims 41 to 54, comprising 0.3 to 1.5 parts by weight of the non-spherical inorganic oxide fine particles (B) based on 0 part by weight. 59. The inorganic oxide fine particles (A) have at least one inorganic oxide selected from the group consisting of titanium oxide and alumina.
The image forming apparatus according to any one of 1 to 58. 60. The non-spherical inorganic oxide fine particles (B)
The image forming apparatus according to any one of claims 41 to 59, wherein the image forming apparatus is silica. 61. The image forming apparatus according to claim 41, wherein the inorganic oxide fine particles (A) have a BET specific surface area of 60 to 230 m ² / g. 62. B of the non-spherical inorganic oxide fine particles (B)
ET specific surface area, the image forming apparatus according to any one of claims 41 to 61, characterized in that a 20~90m ² / g. 63. The method according to claim 41, wherein at least a part of the spherical magnetic powder-dispersed carrier is mixed with at least one external additive before being mixed with the non-magnetic toner. An image forming apparatus according to any one of the above. 64. The spherical magnetic powder-dispersed carrier is produced by a polymerization method.
3. The image forming apparatus according to any one of 3. 65. The image forming apparatus according to claim 41, wherein the spherical magnetic powder-dispersed carrier contains a phenol resin as a binder resin. 66. The spherical magnetic powder-dispersed carrier has a nonmagnetic metal oxide.
65. The image forming apparatus according to any one of claims 65 to 65. 67. The carrier according to claim 41, wherein the spherical magnetic powder-dispersed carrier is a carrier whose surface is coated with a resin using resin particles in which magnetic powder is dispersed as carrier core particles. An image forming apparatus according to any one of the above. 68. The resin according to claim 67, wherein the resin which coats the surface of the carrier core material particles is a silicone resin, a fluororesin, or a copolymer or a mixture of a fluororesin and an acrylic resin. Image forming device. 69. The image forming apparatus according to claim 41, wherein the spherical magnetic powder-dispersed carrier has a weight average particle diameter of 20 to 60 μm. 70. The image forming apparatus according to claim 41, wherein the spherical magnetic powder-dispersed carrier has a shape factor SF-1 of 100 to 140. 71. The image forming apparatus according to claim 41, wherein the spherical magnetic powder-dispersed carrier has a volume resistance of 10 ⁹ to 10 ¹⁵ Ωcm. 72. The non-magnetic toner particles are toner particles produced by a polymerization method.
72. The image forming apparatus according to any one of 1 to 71. 73. The image forming apparatus according to claim 72, wherein said non-magnetic toner particles have a core / shell structure. 74. The shape factor SF- of the non-magnetic toner particles
5. The method according to claim 4, wherein 1 is 100 to 140.
74. The image forming apparatus according to any one of 1 to 73. 75. The shape factor SF- of the nonmagnetic toner particles
5. The method according to claim 4, wherein 2 is 100 to 120.
75. The image forming apparatus according to any one of 1 to 74. 76. The image forming apparatus according to claim 41, wherein the non-magnetic toner particles have a weight average particle diameter of 3 to 9 μm. 77. The apparent density of the two-component developer is as follows:
The image forming apparatus according to any one of claims 41 to 76, characterized in that a 1.2~2.0g / cm ^3. 78. The compression degree of the two-component developer is 5 to 1
The image forming apparatus according to any one of claims 41 to 77, wherein the ratio is 9%. 79. A developer regulating blade for regulating a layer thickness of a two-component developer carried on the developer carrying member, the developer regulating blade being disposed below the developer carrying member.
79. The image forming apparatus according to any one of 1 to 78. 80. The image forming apparatus according to claim 41, wherein said charging means is magnetic brush charging.