JP3332741B2 - Electrostatic image developing toner and image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a toner for developing an electrostatic image such as electrophotography and electrostatic printing, and an image forming method using the toner.

[0002]

2. Description of the Related Art Conventionally, many methods are known as electrophotography. In general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means. The latent image is developed with a toner to form a visible image, and if necessary, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat, pressure, etc. to obtain a copy. The toner remaining on the photoreceptor is cleaned by various methods, and the above steps are repeated.

In recent years, devices using electrophotography have been increasing in number, such as printers and facsimile machines, in addition to conventional copying machines. Particularly in printers and facsimile machines, since it is necessary to reduce the size of the copying device, a developing device using a one-component toner is often used, and among these, a magnetic one-component developer composed of magnetic toner particles is used. The method is excellent.

[0004] Among them, a toner carrier and an electrostatic latent image carrier are arranged at a certain gap, and a thin layer of magnetic toner which does not contact the latent image carrier is formed on the toner carrier. A jumping development method in which an alternating electric field is applied between a carrier and a latent image carrier to perform development (Japanese Patent Laid-Open No. 58-32)
375) is preferably used.

According to this method, the magnetic toner is applied very thinly on the toner carrier to increase the chance of contact between the toner carrier and the toner, enabling sufficient frictional charging, and supporting the magnetic toner by magnetic force. In addition, by moving the magnet and the toner relatively, the aggregation of the toner particles is prevented, and the toner and the toner carrier are sufficiently rubbed, so that an excellent image can be obtained.

In recent years, LED and laser beam printers have become the mainstream in the market for printer devices.
400 dpi, 600 dpi, 1200 dpi
It has become Accordingly, a higher definition has been required for the developing method.
No. 53, Japanese Patent Application Laid-Open No. 2-284158, and the like have proposed toners having a small particle diameter.

However, while making it possible to output a high-resolution and high-definition image by reducing the particle size of the toner, the following problems tend to occur.

[0008] When the toner particle diameter is small, the adhesive force becomes strong, so that the toner is not easily transferred to the transfer material and easily remains on the photoreceptor. Further, the toner easily slips through the cleaner. And may contaminate, cause poor charging, or cause drum fusion.

Further, by reducing the particle size of the toner particles, the fluidity of the developer deteriorates, and the toner is easily fused to the toner carrier and the toner is developed on a non-image area called fog. It has been known.

[0010] To improve these problems, treatment of various inorganic oxide fine powders has been studied.

For example, JP-A-49-42354 and JP-A-55-26518 disclose that a powder of silica or the like is treated with silicone oil to improve especially the fluidity of the toner.

Further, JP-A-58-60754 discloses a toner containing wet silica treated with silicone oil, and JP-A-61-277964 discloses a toner containing silica treated with silicone oil and having a hydrophobicity of 90% or more. It is disclosed to improve toner fluidity and charging characteristics, respectively.

JP-A-61-249059 discloses a magnetic developer carrying hydrophobic silica and hydrophilic silica treated with silicone oil on the surface of a toner, and JP-A-4-264453. A configuration for reducing fog by using a toner containing inorganic oxide particles having a specific surface area of 10 to 100 m ² / g or more, which is surface-treated with silicone oil, in an AC application development system is disclosed.

Japanese Patent Application Laid-Open No. 60-186854 proposes adding fine resin particles to a developer. When a developer was prepared and examined in the same manner as above, the effect of preventing fusion of the toner on the photoreceptor was small, and in a device using contact charging, the contact charging device was contaminated,
Charge unevenness occurred.

As described above, the performance improvement of the toner is still insufficient, and has many points to be improved.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrostatic image development capable of outputting a high-resolution and high-definition image without fusing toner to a photosensitive member or contaminating a contact charging member. And an image forming method.

It is a further object of the present invention to provide an electrostatic image developing toner having excellent fluidity, high image density and no fog, and an image forming method.

It is a further object of the present invention to provide a toner for developing an electrostatic charge image and an image forming method, which has a fast rise of charging, does not fuse the toner to a toner carrier, and has excellent durability.

[0019]

According to the present invention, the content of at least toner particles, fine resin particles , (i) silicone oil or silicone varnish is 20 to 90% by weight.
And (ii) a silane coupling agent and
Treated with silicone oil or silicone varnish
And the BET specific surface area is 80 to 140 m ² / g.
And a second inorganic fine powder according to claim 1, wherein the particle size distribution of the toner is such that the weight average particle diameter (D ₄ ) is X (μm), and the number is based on the number distribution obtained from the number distribution. When the number% of toner particles having a particle size of 3.17 μm or less is Y (number%), X and Y satisfy the following condition: −5X + 35 ≦ Y ≦ −25X + 180 3.5 ≦ X ≦ 6.5. And a toner for developing an electrostatic image.

Further, the present invention relates to an image forming method comprising a step of forming a toner layer on a toner carrier opposed to an electrostatic latent image carrier and developing the electrostatic latent image on the electrostatic latent image carrier. An image forming method, wherein the toner carrier has at least a substrate and a conductive coating layer, the surface of the substrate is coated with the conductive coating layer, and the toner for developing an electrostatic image is used. About.

Further, the present invention has a charging step of charging by bringing a charging member to which an external voltage is applied into contact with an electrostatic latent image holding member, and further comprises the toner carrier and the toner for developing an electrostatic image. The present invention relates to an image forming method characterized by using the following.

By reducing the particle size of the toner particles, it is possible to obtain a high-quality image faithfully reproducing an electrostatic latent image. However, the particle size is less than 3.17 μm, especially 2.5
Since the toner fine powder having a small particle diameter of less than 2 μm has a strong adhesive force, it tends to remain on the photoreceptor without being cleaned after the transfer, and the toner particles fuse to the photoreceptor,
In an apparatus using a contact charging member, the contact charging member is contaminated, which causes charging failure. Further, when the particle size of the toner particles is reduced, the specific surface area increases, so that the magnetic iron oxide or the like is easily detached from the toner surface, and is easily released. The magnetic iron oxide in a free state is very small and has a strong adhesive force, and because of its hardness, it easily damages the photoreceptor and easily adheres to the contact charging member, causing toner fusion to the photoreceptor and contamination of the contact charging member. It turned out that it is easy to make the cause of charging failure.

In the present invention, an appropriate amount of silicone oil or silicone varnish is always applied to the surface of a photoreceptor or a contact charging member by adding an inorganic fine powder containing 20 to 90% by weight of silicone oil or silicone varnish to toner particles. Work to coat the surface with silicone oil or silicone varnish. For this reason, it is considered that the surface of the photoconductor and the contact charging member is in a state where toner fine powder and free magnetic iron oxide are hardly attached. In a toner having a particle size distribution as defined above, in a toner to which the inorganic fine powder treated with the silicone oil or silicone varnish is not added, while maintaining the fluidity and chargeability of the toner, the photosensitive member and the contact charge It is difficult to make the surface of the member difficult to adhere to the toner fine powder and free magnetic iron oxide.

Further, at the contact portion between the photoreceptor and the contact charging member, the resin fine particles take in the magnetic iron oxide in a free state adhering to the surface of the photoreceptor and the contact charging member into the resin fine particles, thereby facilitating the cleaning. Also, the contact area between the toner fine powder and the surface of the photoconductor or the contact charging member which is present between the toner fine powder and the surface of the photoconductor or the contact charging member is reduced, and the fine resin particles act like a roller so that the fine particles of the resin act like rollers. And has the effect of making it difficult to adhere to the surface of the contact charging member. However, if resin fine particles are present in a state where the surface of the photoreceptor and the contact charging member is coated with silicone oil or silicone varnish as described above, these effects are greatly enhanced. It became clear that it improved.

As described above, the addition of the resin fine particles and the inorganic fine powder having a content of at least 20 to 90% by weight of silicone oil or silicone varnish to the toner having the above-mentioned particle size distribution makes it impossible to fuse the toner to the photosensitive member for the first time. It is possible to prevent contamination of the contact and charging members.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the particle size distribution of the toner is such that the weight average particle size (D ₄ ) is X (μm), and the number of toner particles having a particle size of 3.17 μm or less obtained from the number distribution. % As Y (number%), −5X + 35 ≦ Y ≦ −
25X + 180, more preferably −5X + 35 ≦ Y ≦ −
12.5X + 98.75; 3.5 ≦ X ≦ 6.5, more preferably 4.0 ≦ X ≦ 6.3.

When X is larger than 6.5 μm, the reproducibility of one dot is inferior, which is not preferable. On the other hand, when the thickness is smaller than 3.5 μm, the developer tends to be charged up, and a problem such as a decrease in image density tends to occur, which is not preferable. On the other hand, when Y (number%) is smaller than −5X + 35, X is 6.5 μm.
As in the case where the value is larger than m, the reproducibility of one dot is inferior and the resolution is low, which is not preferable. Y (number%) is -2
If it is larger than 5X + 180, it is not preferable because fog on the non-image portion increases, and charging failure occurs due to fusion of the toner to the photoconductor and contamination of the contact charging member.

Further, the weight average particle size (D ₄ ) of the toner is defined as X (μm), and the particle size distribution in the number distribution of the toner is 2.5 (μm).
When the ratio of toner particles of 2 μm or less is defined as Z (number%), it is more preferable that the following condition is satisfied: −7.5X + 45 ≦ Z ≦ −12.0X + 82.

The ratio Z (number%) of the toner particles having a particle size of 2.52 μm or less has a great influence on the fusion of the toner to the photosensitive member and the contamination of the contact charging member. Z (number%) is-
If it is smaller than 7.5X + 45, the resolution becomes low, which is not preferable. Z (number%) is -12.0X + 8
If it is larger than 2, it is not preferable because fog increases, toner is fused to the photoreceptor, and the contact charging member is contaminated to cause poor charging.

The average particle size and particle size distribution of the developer are measured using a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter Inc.). As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of the electrolytic aqueous solution, and a measurement sample is further added to 2 to 20 ml.
Add mg. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles of 2 μm or more were measured using a 100 μm aperture as the aperture by the Coulter Counter TA-II. To calculate the volume distribution and the number distribution. Then, the weight-based weight average particle diameter (D ₄ : the median value of each channel is a representative value of the channel) obtained from the volume distribution according to the present invention and the number-based 3.1 obtained from the number distribution.
The ratio of 7 μm or less was determined.

Further, in the present invention, the porosity at the time of tapping of the toner defined by the following formula is preferably in the range of 0.45 to 0.70, more preferably 0.50 to 0.70.
Excellent chargeability is exhibited when it is in the range of 0.70, more preferably in the range of 0.50 to 0.60.

Porosity = (true density−tap density) / true density

The toner is charged by friction in a state where it is packed mainly between the toner carrier and the toner regulating blade. Therefore, the degree of the packing state of the toner greatly affects the charging of the toner. When the toner has the porosity in the above range, the toner is easily moved on the toner carrier, and the charging opportunity of each toner particle is uniform, so that the variation of the charging amount of each toner particle is suppressed and the fog is reduced. be able to.

The inorganic fine powder used in the present invention includes Si
O ₂ , GeO ₂ , TiO ₂ , SnO ₂ , Al ₂ O ₃ , B ₂ O ₃ ,
Oxides such as P ₂ O ₅ and As ₂ O ₃ , silicates, borates, phosphates, borosilicates, aluminosilicates, aluminoborates, aluminoborosilicates, tungstates, molybdates And metal oxide salts such as tellurate, and composite compounds thereof, silicon carbide, silicon nitride, amorphous carbon and the like. These can be used alone or in combination.

As the inorganic fine powder, an inorganic compound fine powder can be used under production by a dry method and a wet method. The dry method referred to here is a method for producing an inorganic fine powder produced by vapor phase oxidation of a halide. For example, the basic reaction formula in the method utilizing the thermal decomposition oxidation reaction of a halide gas in oxygen-hydrogen is as follows.

MX_Four+2 H_Two+ ／ O_Two → MO_Two+4
HX (M: tetravalent)

In this formula, for example, M is a metal or metalloid element, X is a halogen element, and n is a reaction formula representing an integer. Specifically, AlCl ₃ , TiCl ₄ , GeCl ₄ ,
When SiCl ₄ , POCl ₃ , and BBr ₃ are used, Al ₂ O ₃ , TiO ₂ , GeO ₂ , SiO ₂ , P ₂ O ₅ , and B ₂ O are used, respectively.
₃ is obtained. At this time, if a mixture of halides is used, a composite compound can be obtained.

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

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

Na ₂ O.xSiO ₂ + 2HCl + nH ₂ O
→ xSiO ₂ · nH ₂ O + 2NaCl

Also, a method of decomposing sodium silicate with ammonium salts or alkali salts, a method of forming an alkaline earth metal silicate from sodium silicate and then decomposing it with an acid to form silicic acid, and a method of ion-exchanging a sodium silicate solution There are a method of using silicic acid with a resin, a method of using natural silicic acid or silicate, and the like. Other methods include hydrolysis of metal alkoxides. The general reaction formula is shown below.

M (OR) ₄ O + 2H ₂ O → MO ₂ +4
ROH (M: tetravalent)

In this formula, for example, M represents a metal or metalloid element, R represents an alkyl group, and n represents an integer. At this time, if two or more metal alkoxides are used, a composite can be obtained.

Of these, inorganic compounds are particularly preferable because of their appropriate electric resistance. Metal oxides are particularly preferable. In particular,
Oxides and double oxides of Si, Al and Ti are preferred.

Further, a material whose surface has been previously rendered hydrophobic with a coupling agent or the like may be used.

The particle size of the fine particles is preferably 0.0
It is preferably from 0.01 to 20 μm, particularly preferably from 0.005 to 10 μm. B
The specific surface area by nitrogen adsorption measured by the ET method is 1
0~400m ² / g, more preferably 50~400m ² /
g, more preferably 100 to 350 m ² / g.
If it is less than 10 m ² / g, it tends to be difficult to hold a large amount of the silicone oil or silicone varnish of the present invention as lubricating particles having a suitable particle size.

The silicone oil used in the present invention has a general formula

[0048]

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(Where R represents an alkyl group having 1 to 3 carbon atoms, R ′ represents a silicone oil-modified group such as alkyl, halogen-modified alkyl, phenyl and modified phenyl, and R ″ represents 1 to 3 carbon atoms. And m and n each represent an integer.), For example, dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified And silicone oil.

As the silicone varnish used in the present invention, known substances can be used, and examples thereof include KR-251 and KP-112 manufactured by Shin-Etsu Silicone Co., Ltd.

In the present invention, an amino-modified silicone oil having a structure represented by the formula (I) can be used as the silicone oil.

[0052]

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(Where R ₁ and R ₆ are hydrogen, an alkyl group,
R ₂ represents an alkylene group or a phenylene group; R ₃ represents a compound having a nitrogen-containing heterocyclic ring in its structure; R ₄ and R ₅ represent a hydrogen, an alkyl group, or an aryl group . R ₂ may not be present. However, the above-mentioned alkyl group, aryl group, alkylene group and phenylene group may contain an amine or may have a substituent such as halogen as long as the chargeability is not impaired. M is a number of 1 or more, and n and k are positive numbers including 0. Here, n + k is a positive number of 1 or more. )

The most preferred structure among the above structures is one in which the number of nitrogen atoms in the side chain containing a nitrogen atom is one or two.

Examples of the nitrogen-containing unsaturated heterocycle are shown below.

[0056]

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Examples of the nitrogen-containing saturated heterocycle are shown below.

[0058]

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However, the present invention is not limited to the above compound examples, but preferably has a 5-membered or 6-membered heterocyclic ring.

As the derivatives, a hydrocarbon group, a halogen group, an amino group, a vinyl group, a mercapto group,
Derivatives into which a methacryl group, a glycidoxy group, a ureido group, etc. are introduced are exemplified.

These may be used alone or in a mixture of two or more.

The silicone varnish used in the present invention includes, for example, methyl silicone varnish, phenylmethyl silicone varnish and the like, and methyl silicone varnish is particularly preferred.

The methyl silicone varnish is a polymer composed of T ³¹ units, D ³¹ units and M ³¹ units represented by the following structural formula, and is a three-dimensional polymer containing a large amount of T ³¹ units.

[0064]

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The methyl silicone varnish or the phenylmethyl silicone varnish is a substance having a chemical structure represented by, for example, the following structural formula (II).

[0066]

Embedded image

(R ³¹ represents a methyl group or a phenyl group.)

In the above silicone varnish, in particular, T ³¹
The unit is an effective unit for imparting good thermosetting properties and forming a three-dimensional network structure. The T ³¹ unit is 10 to 90 mol% in a silicone varnish, in particular 30 to 80 mol%
Is preferably contained at a ratio of

Such a silicone varnish has a hydroxyl group at a terminal or a side chain of a molecular chain, and is cured by dehydration condensation of the hydroxyl group. Examples of the curing accelerator that can be used to accelerate this curing reaction include fatty acid salts such as zinc, lead, cobalt, and tin; amines such as triethanolamine and butylamine; and the like. Of these, amines can be particularly preferably used.

In order to make the above-mentioned silicone varnish into an amino-modified silicone varnish, the above-mentioned T ³¹ unit and D ³¹
Units, some of the methyl group or a phenyl group present in the M ³¹ unit may be replaced with a group having an amino group. Examples of the group having an amino group include, but are not limited to, those represented by the following structural formula.

[0071]

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The silicone oil or silicone varnish has a viscosity at 25 ° C., preferably 50 to 20.
000 centistokes, more preferably 500
〜150,000 centistokes, more preferably 1,500-100,000 centistokes, and even more preferably 3,000-80,000 centistokes.

If the density is less than 50 centistokes, it is difficult to form a large amount of silicone oil or silicone varnish with good particles, and there is no stability, and image quality tends to deteriorate due to heat and mechanical stress. 200,0
If it exceeds 00 centistokes, it tends to be difficult to form particles of silicone oil or silicone varnish.

The viscosity of the silicone oil or silicone varnish is measured using a Visco Tester VT500 (manufactured by Haake). One of several viscosity sensors for VT500 is selected (arbitrary), and a measurement sample is put in a measurement cell for the sensor to measure. The viscosity (pas) displayed on the device is converted to cSt (centistokes).

The desired effect can be obtained when the amount of silicone oil or silicone varnish in the inorganic fine powder is 20 to 90% by weight, preferably 30 to 85% by weight.

When the amount of silicone oil or silicone varnish is less than 20% by weight, the effect of applying an appropriate amount of silicone oil or silicone varnish to a photoreceptor or a contact charging member is small. On the other hand, when the content exceeds 90% by weight, it becomes difficult to hold the silicone oil or silicone varnish on the particles, and the excess silicone oil or silicone varnish aggregates the toner particles, and the image quality tends to deteriorate.

The inorganic fine powder composed of silicone oil or silicone varnish and fine particles has a specific surface area of 0.01 to 50 m ² / g (preferably 0.05 to 30 m ² / g).
m ² / g, more preferably 0.1 to 10 m ² / g) good results are obtained.

If it exceeds 50 m ² / g, the silicone oil or silicone varnish is difficult to hold as particles, causing aggregation of the toner, and image quality is likely to deteriorate. If it is less than 0.01 m ² / g, the image quality tends to deteriorate.

The specific surface area is a value calculated by the following method. According to the BET method, nitrogen gas is adsorbed on the sample surface using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics), and the specific surface area is calculated using the BET multipoint method.

The application amount of the inorganic fine powder containing silicone oil or silicone varnish is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, and still more preferably 100 parts by weight of the toner. 0.05 ~
2 parts by weight is good. If the amount is less than 0.01 part by weight, the effect of applying to the photoreceptor or the contact charging member is small, and if it exceeds 10 parts by weight, the fixability of the toner tends to be impaired.

The inorganic fine powder according to the present invention contains a relatively large amount of 20 to 90% by weight of a substance having good releasability such as silicone oil or silicone varnish. It works to improve the releasability from the surface and the surface of the contact charging member.

Silicone oil is more preferred than silicone varnish because silicone oil is more easily applied to the surface of a photoreceptor or the surface of a contact charging member. It is preferable that the silicone oil does not contain an alkoxy group.

In the present invention, the toner is treated with a silane coupling agent and a silicone oil or a silicone varnish, and has a BET specific surface area of 80 to 14.
It is more preferable to contain a second inorganic fine powder of 0 m ² / g. By the presence of such a second inorganic fine powder, the adhesion of the toner fine powder can be reduced, and the effect obtained by the inorganic fine powder containing 20 to 90% by weight of silicone oil or silicone varnish can be further enhanced. It becomes possible.

The second inorganic fine powder used in the present invention is:
The same inorganic fine powder as above is treated with a silane coupling agent and then treated with silicone oil or silicone varnish is more preferably used.

The second inorganic fine powder is treated under the following conditions: a silane coupling reaction is performed as a first step reaction to eliminate silanol groups by a chemical bond; and a second step reaction is carried out using silicone oil or silicone varnish. In which a hydrophobic thin film is formed.

The silane coupling agent used in the present invention has the general formula R _m SiY _n

[Wherein, R represents an alkoxy group or a chlorine atom, m represents an integer of 1 to 3, Y represents an alkyl group,
It represents a hydrocarbon group containing a vinyl group, a glycidoxy group or a methacryl group, and n represents an integer of 3 to 1. ] Are preferred. For example, typically, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyl Triacetoxysilane,
Examples thereof include divinylchlorosilane and dimethylvinylchlorosilane.

The silane coupling agent treatment of the fine powder may be a dry process in which a vaporized silane coupling agent is reacted with a cloud of the fine powder by stirring or the like, or a silane coupling agent in which the fine powder is dispersed in a solvent. The treatment can be performed by a method such as a wet method in which a ring agent is dropped and reacted. Among them, a dry treatment method is particularly preferably used, but is not limited thereto.

As the substance used for the silicone oil or silicone varnish treatment, the aforementioned substances may be used. Although the same method can be used as the treatment method, for example, a method using a sprayer is preferably used.

The silicone oil or silicone varnish suitably used for the second inorganic fine powder preferably has a viscosity at 25 ° C. of 50 to 1000 centistokes. If it is less than 50 centistokes, the effect of weakening the adhesion of the toner particles is small, and if it exceeds 1000 centistokes, the fluidity of the toner deteriorates.

The silane coupling agent may be treated in an amount of 1 to 40 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the fine powder. The treatment amount of the silicone oil or silicone varnish solid is 1 to 23 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the fine powder.

If the amount of the silane coupling agent is too small, good moisture resistance is inferior. If the amount is too large, problems such as a decrease in image density occur. If the amount of silicone oil or silicone varnish is too small, the effect of weakening the adhesion of the toner is small,
If the amount is too large, there arises a problem that the fluidity of the toner cannot be improved.

As the characteristic value of the second inorganic fine powder, the specific surface area by nitrogen adsorption measured by the BET method is 8
Those in the range of 0 to 140 m ² / g are preferred. The second inorganic fine powder was added in an amount of 0.2 to 100 parts by weight of the magnetic toner.
It is good to use -3.0 parts by weight, preferably 0.4-2.0 parts by weight.

The resin fine particles used in the present invention are styrene organic fine particles, and the volume specific resistance of the styrene organic fine particles after drying at 40 ° C. is 10 ⁷ to 10 ¹⁴ Ω · cm.
And have an average particle size of 0.03 to 1.0 μm, a surface area sphericity (ψ ₁ ) of 0.9 to 0.50, and a glass transition point (Tg) of 80 to 110 ° C. Is preferred.

When the volume resistivity is less than 10 ⁷ Ω · cm, the charge amount of the toner tends to decrease, and when it exceeds 10 ¹⁴ Ω · cm, the fluidity of the toner tends to decrease.

When the average particle diameter is less than 0.03 μm, the ability to act as a roller between the toner particles and the photoreceptor or the contact charging member is small, and when the average particle diameter exceeds 1.0 μm, the fluidity tends to decrease.

When the sphericity (ψ ₁ ) of the surface area is less than 0.50, the surface has many irregularities, and the projections are chipped to generate fragments, which tends to cause toner charge-up. 0.
If it exceeds 90, the surface area becomes small, and the ability to take free magnetic iron oxide into the resin fine particles decreases.

When the glass transition point (Tg) is less than 80 ° C., the glass is liable to be fused by the influence of heat such as a temperature rise in the apparatus.
If the temperature exceeds 10 ° C., the material of the resin fine particles becomes hard, and the photosensitive member is easily damaged.

The resin fine particles are preferably used in an amount of 0.01 to 1.0 part by weight based on 100 parts by weight of the toner.

The fine resin particles are produced by an emulsion polymerization method, a spray drying method or the like. Preferably, a glass transition point of 80 ° C. obtained by copolymerizing components used for a toner binder resin such as styrene, acrylic acid, methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate by an emulsion polymerization method, a soap-free polymerization method, or the like. The above resin particles show a good effect. Further, it may be cross-linked with divinylbenzene or the like, and it is also preferable in the present invention that the surface is treated with a metal, a metal oxide, a pigment, a dye, a surfactant or the like for adjusting the specific electric resistance and the triboelectric charge. It is a form.

An example of the measurement of the specific electric resistance (volume specific resistance) in the present invention will be described. Using the device shown in FIG.
The sample is formed into tablets. First, about 0.3 g of the sample is placed in the tableting chamber. Next, the push rod 42 is inserted into the tablet molding chamber, and pressurized at 250 kg / cm ² for 5 minutes by the hydraulic pump 45 to form a pellet-shaped tablet having a diameter of about 13 mm and a height of about 2 to 3 mm.

The tablets obtained here are coated with a conductive agent on the front surface and the back surface as required, for example, HEWLETT.
16008A RESISTIVIT manufactured by PAKARD
YCELL; or 4329A HIGH RE manufactured by the company
Temperature 23.5 using SISTANCE METER
A resistance value when a voltage of 1000 V is applied is measured in an environment of a temperature of 65 ° C. and a humidity of 65% RH, and a specific electric resistance value ρ is obtained by calculation.

[0103]

(Equation 1) (Where S is the cross-sectional area of the sample and 1 is the height of the sample)

The surface area shape sphericity (ψ) of the resin fine particles is defined as follows.

[0105]

(Equation 2)

The actual measurement of the BET specific surface area can be performed, for example, by using QUAN
When the specific surface area meter Autosorb 1 manufactured by TACHROME is used, examples of the measuring method include the following.

About 0.3 g of resin fine particles were weighed into a cell,
Deaeration is performed at a temperature of 40 ° C. and a degree of vacuum of 1.0 × 10 ⁻³ mmHg for 1 hour or more. Thereafter, nitrogen gas is adsorbed in a state of being cooled by liquid nitrogen, and a value is obtained by a multipoint method.

Assuming that the fine resin particles are spherical, the surface area is, for example, an electron micrograph (× 1000) of the fine resin particles.
From 0), 100 resin fine particle images are randomly selected, their major diameters are measured, and the average diameter value is defined as the diameter when the resin fine particles are assumed to be true spheres. Based on this diameter, the radius γ of the resin fine particles is determined, and further, the surface area (4πγ ² ) of the resin fine particles is determined. In addition, the volume of resin particles

[0109]

(Equation 3) And the weight of the resin fine particles is determined from the density of the resin fine particles and the volume. From the obtained surface area and the weight, the surface area (m ² / g) assuming that the resin fine particles are spherical is determined.

In the present invention, the glass transition point Tg of the fine resin particles is determined by a differential thermal analyzer (DSC analyzer),
-7 (manufactured by PerkinElmer).

The measurement sample is 5 to 20 mg, preferably 10
Weigh the mg precisely. This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and the measurement is performed at a temperature rising rate of 10 ° C./min under normal humidity within a measurement temperature range of 30 ° C. to 200 ° C. During this heating process, the temperature is 40 to 180.
An endothermic peak of the main peak in the range of ° C is obtained. The intersection between the line at the midpoint of the baseline before and after the endothermic peak appeared and the differential heat curve was obtained.

The toner used in the present invention has a sphericity (ψ ₂ ).
It is preferable that the toner is a magnetic toner containing a magnetic iron oxide of 0.8 or more. When the sphericity (ψ ₂ ) is less than 0.8, the surface area of the magnetic iron oxide is large, and the contact portion between the magnetic iron oxide particles is large, so that the cohesiveness of the magnetic iron oxide increases and the magnetic iron oxide is uniformly dispersed in the toner particles. And it is difficult to disperse them. For this reason, the image density decreases and fog increases.

The calculation of the sphericity of the magnetic iron oxide in the present invention is performed as follows.

[0114]

(Equation 4)

Using a sample of magnetic iron oxide treated on a copper mesh of a collodion film using an electron microscope (H-700H, manufactured by Hitachi, Ltd.), an image was taken at 10,000 times at an applied voltage of 100 kV, and the printing magnification was set to 3 times. The magnification is 30,000 times.

The sphericity ψ ₂ is obtained by randomly selecting 100 magnetic iron oxide particle specimens from a photograph, measuring the maximum length and the minimum length, and then averaging the calculated values.

The magnetic material is preferably contained in the toner in an amount of preferably from 60 to 200 parts by weight, more preferably from 80 to 150 parts by weight, based on 100 parts by weight of the binder resin.

On the other hand, in the image forming method of the present invention, the surface of the base of the toner carrier is coated with a conductive coating layer, and preferably, the conductive coating layer has a number average diameter of at least 0.1 in the binder resin. It contains spherical particles of ^{3 to 30} μm, more preferably the conductive spherical particles have a true density of 3 g / cm ³ or less, and more preferably the conductive spherical particles are carbon particles.

Since the surface of the base of the toner carrier is covered with the conductive coating layer, uniform and stable chargeability of the toner can be obtained over a long period of time, and stable toner is less affected by temperature and humidity environment. Charging is obtained.

When the number average diameter of the spherical particles is less than 0.3 μm, the effect of imparting uniform roughness to the surface is small, and charge-up of the toner due to abrasion of the coating layer, toner fusion and the like are liable to occur. On the other hand, when the number average diameter of the spherical particles is 3
If the thickness exceeds 0 μm, the surface roughness becomes too large and the toner is not sufficiently charged, and the mechanical strength of the coating layer is undesirably reduced.

Further, the conductive spherical particles used in the present invention have a true density of 3 g / cm ³ or less. If the true density of the spherical particles exceeds ³ g / cm ³ , the dispersibility of the spherical particles in the conductive coating layer becomes insufficient, so that it is difficult to impart uniform roughness to the surface of the coating layer, and the toner is uniformly charged. And the strength of the coating layer becomes insufficient, which is not preferable.
In addition, the toner can be prevented from being fused by being made conductive.

Further, when the conductive spherical particles are carbon particles, a toner carrier excellent in durability with little wear of the coating layer can be obtained for a long term.

In the present invention, the term “spherical” in the spherical particles refers to those having a ratio of the major axis / minor axis of the particles of about 1.0 to 1.5, more preferably 1.0 to 1.2. I do. In particular, it goes without saying that it is preferable to use true spherical particles.

The conductivity of the conductive spherical particles as described above is preferably not more than 10 ⁶ Ω · cm in volume resistivity. If the volume resistivity of the spherical particles exceeds 10 ⁶ Ω · cm, the toner tends to be contaminated or fused with the spherical particles exposed on the surface of the conductive coating layer due to abrasion as nuclei.
Not preferred.

As a method for obtaining the conductive spherical particles used in the present invention as described above, the following methods are preferable, but are not necessarily limited thereto.

The method for obtaining particularly preferred conductive spherical particles used in the present invention includes, for example, phenol resin,
Resin-based spherical particles such as naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile and mesocarbon microbeads are calcined and carbonized and / or graphitized to reduce A method for obtaining spherical carbon particles of high density and good conductivity, more preferably on the surface of spherical particles such as phenolic resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile, etc. A method in which a bulk mesophase pitch is coated by a mechanochemical method, and the coated particles are heat-treated in an oxidizing atmosphere and then fired to be carbonized and / or graphitized to obtain conductive spherical carbon particles. . The conductive spherical carbon particles obtained by the above method can control the conductivity of the spherical carbon particles obtained by changing the firing conditions and the like to some extent in any method, and are preferably used in the present invention. Is done. Further, in some cases, the spherical carbon particles obtained by these methods are plated with a conductive metal and / or metal oxide so that the true density does not exceed ³ g / cm ³ in order to further enhance the conductivity. May be applied.

As another method for obtaining conductive spherical particles preferably used in the present invention, conductive fine particles smaller than the particle diameter of the core particles are added to the surface of the core particles composed of spherical resin particles at an appropriate mixing ratio. After the conductive particles are uniformly mixed around the resin particles by the action of van der Waals force and electrostatic force, the local temperature rise caused by, for example, mechanical impact force A method of softening the surface of the resin particles, forming a film of conductive fine particles on the surface of the core particle, and obtaining conductive treated spherical resin particles. At this time, as the constituent material of the core particles, it is preferable to use a resin that is a spherical organic compound having a small true density, for example, PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, or these. And resin particles such as benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone resin, epoxy resin and polyester resin. The conductive fine particles (small particles) used when forming a film on the surface of such a core particle (base particle) have a particle diameter of the mother particle in order to uniformly provide a conductive fine particle coating. It is preferable to use one having a particle size of 1/8 or less of the particle size.

Further, as another method of obtaining conductive spherical particles preferably used in the present invention, a method of uniformly dispersing conductive fine particles in spherical resin particles to obtain spherical particles in which conductive fine particles are dispersed is provided. There is. As a method of uniformly dispersing the conductive fine particles in the spherical resin particles, for example, after dispersing the conductive fine particles in the binder resin, kneading, pulverizing to a predetermined particle size, by mechanical treatment and thermal treatment A polymerization initiator, conductive fine particles and other additives are added to the spherical conductive spherical particles and the polymerizable monomer, and a monomer composition uniformly dispersed by a disperser or the like is used as a dispersion stabilizer. The particles are suspended in a water phase containing the particles by a stirrer or the like so as to have a predetermined particle diameter, and polymerized to obtain spherical particles in which conductive fine particles are dispersed. The conductive spherical particles in which the conductive fine particles obtained by these methods are dispersed are mechanically mixed with conductive fine particles having a particle diameter smaller than the above-mentioned core particles at an appropriate mixing ratio, and van der Waals force and After uniformly attaching the conductive fine particles around the spherical resin particles by the action of electrostatic force, for example,
The surface of the resin particles in which the conductive fine particles are dispersed may be softened by a local temperature rise caused by a mechanical impact force or the like, and the conductive fine particles may be formed into a film.

In the conductive coating layer constituting the toner carrier used in the present invention, when the lubricating substance is dispersed in the coating resin layer in combination with the conductive spherical particles as described above, the present invention can be further improved. This is preferred because the effect of is promoted. As the lubricating substance used at this time, for example, fatty acid metal salts such as graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc and zinc stearate Among them, graphite is particularly preferably used because the conductivity of the coating layer is not impaired when used in combination.
Further, as these lubricating substances, those having a number average particle size of about 0.2 to 20 μm are preferably used.

The conductive coating layer constituting the toner carrier used in the present invention is formed by dispersing the conductive spherical particles and the lubricating substance as described above in a binder resin. As the binder resin material used in (1), generally known resins can be used. For example, styrene resin, vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, cellulose resin, thermoplastic resin such as acrylic resin, epoxy resin, polyester resin, alkyd resin For example, a heat or light curable resin such as a phenol resin, a melamine resin, a polyurethane resin, a urea resin, a silicone resin and a polyimide resin can be used. Among them, those having release properties such as silicone resin and fluorine resin, or polyether sulfone polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane,
Those having excellent mechanical properties such as styrene resin and acrylic resin are more preferable.

The volume resistivity of the conductive coating layer of the toner carrier used in the present invention is preferably 10 ³ Ω · cm or less. When the volume resistance of the coating layer exceeds 10 ³ Ω · cm, charge-up of the toner is apt to occur, causing ghosting and a decrease in density.

In the toner carrier used in the present invention, other conductive fine particles may be dispersed and contained in the binder resin in order to adjust the volume resistance of the coating layer. Such conductive fine particles preferably have a number average particle size of 1 μm or less.

Examples of the constitution of the conductive fine particles used in the present invention include carbon black such as furnace black, lamp black, thermal black, acetylene black and channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide and titanic acid. Metal oxides such as potassium, antimony oxide and indium oxide; aluminum;
Examples thereof include metals such as copper, silver and nickel, graphite, and inorganic fillers such as metal fibers and carbon fibers.

Next, the structure of the toner carrier used in the present invention will be described. The toner carrier used in the present invention comprises a metal cylindrical tube as a base and a conductive coating layer surrounding and surrounding the metal cylindrical tube. As the metal cylindrical tube, stainless steel, aluminum or the like is preferably used.

The composition ratio of each component constituting the conductive coating layer will be described below, but the following is a particularly preferable range.

Particularly preferable results are obtained when the amount of the conductive spherical particles dispersed in the conductive coating layer is in the range of 2 to 120 parts by weight based on 100 parts by weight of the binder resin. If it is less than 2 parts by weight, the effect of adding the conductive spherical particles is small, and if it exceeds 120 parts by weight, the chargeability of the toner may be too low.

When a lubricating substance is used in combination with the conductive coating layer, a particularly preferable result is obtained in the range of 5 to 120 parts by weight with respect to 100 parts by weight of the binder resin. When the amount exceeds 120 parts by weight, a decrease in film strength and a decrease in the charge amount of the toner are observed.
For example, when the toner is used for a long time using a toner having a small particle diameter of μm or less, fusion of the toner may easily occur on the surface of the coating layer.

Further, as the above-mentioned conductive spherical particles, those obtained by forming conductive fine particles (small particles) on the surface of core particles (base particles) or conductive spherical particles in which conductive fine particles are dispersed are used. When the conductive fine particles having a thickness of 1 μm or less in the conductive coating layer are used in an amount of 40 parts by weight or less based on 100 parts by weight of the binder resin, particularly preferable results are obtained. That is, if it exceeds 40 parts by weight, a decrease in the coating strength and a decrease in the charge amount of the toner are recognized,
Not preferred.

It is preferable that the thickness of the conductive coating layer having the above-mentioned structure is usually 20 μm or less in order to obtain a uniform film thickness, but it is not particularly limited to this thickness.

In the present invention, the coat amount per unit area of the toner layer formed on the toner carrier is w / ρ = 0.2 to 1.0 w; the toner coat weight per 1 cm ^{2 of the} toner carrier surface ( mg) ρ; the toner true density (g / cm ³ ), and the average roughness Ra of the surface of the toner carrier is more preferably 1.8 or less. By making the toner supply amount to the toner carrier w / ρ = 0.2 to 1.0 and making the toner coat layer thin, the rise of the charge is quick and the distribution of the charge amount is narrow, and it is faithful to the latent image. A sharp image can be obtained.

When w / ρ is less than 0.2, when there is a portion such as solid black which requires a large amount of toner for development with high print density, the toner supply amount is insufficient and the image density is reduced.

If w / ρ exceeds 1.0, the distribution of the toner charge amount becomes wide, fog increases, and it becomes difficult to obtain a sharp image.

The true density of the toner was measured by using a dry automatic densitometer "Acupic 1330" manufactured by Shimadzu Corporation.

The toner coating amount w / ρ of the present invention =
In order to achieve 0.2 to 1.0, the average roughness Ra of the surface of the toner carrier is preferably set to 1.8 or less.
If a exceeds 1.8, it becomes difficult to control the coating amount within this range.

The method for measuring physical properties according to the present invention will be described below.

(1) Measurement of Center Line Average Roughness (Ra) Based on the surface roughness of JIS B0601, three points in the axial direction × 2 points in the circumferential direction = 6 points using a surf coder SE-3300 manufactured by Kosaka Laboratory. Each was measured and the average was taken.

(2) Measurement of Volume Resistance of Particles A granular sample was put in an aluminum ring of 40φ, and was press-molded at 2500 N, and a resistivity meter Loresta AP or Hiresta I was used.
The volume resistance is measured at P (both manufactured by Mitsubishi Yuka) using a four-terminal probe. The measurement environment was 20 to 25.
C., 50 to 60 RH%.

(3) Measurement of Volume Resistance of Coating Layer A conductive coating layer having a thickness of 7 to 20 μm was formed on a PET sheet having a thickness of 100 μm, and was subjected to the ASTM standard (D-991).
-82) and SRIS (230
1-1969), using a voltage drop type digital ohmmeter (manufactured by Kawaguchi Electric Works) provided with a four-terminal electrode for measuring the volume resistance of conductive rubber and plastic. The measurement environment was 20 to 25 ° C and 50 to 60 ° C.
RH%.

(4) Measurement of True Density of Spherical Particles The true density of the conductive spherical particles used in the present invention was measured using a dry type densitometer Acupic 1330 (manufactured by Shimadzu Corporation).

(5) Particle Size Measurement of Spherical Particles The particle number was measured using a Coulter LS-130 type particle size distribution analyzer (manufactured by Coulter, Inc.) of a laser diffraction type particle size distribution meter, and the number average particle size calculated from the number distribution was determined. .

(6) Measurement of Particle Size of Conductive Fine Particle The particle size of the conductive fine particle is measured using an electron microscope.
The photographing magnification is set at 60,000 times. If it is difficult, the image is taken at a low magnification and then enlarged to 60,000 times. Measure the particle size of the primary particles on the photograph. At this time, the major axis and the minor axis are measured, and the average value is defined as the particle diameter. This was measured for 100 samples,
The 50% value is defined as the average particle size.

Examples of the type of the binder resin preferably used in the toner particles of the present invention include 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-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, Styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-
Styrene-based copolymers such as isoprene copolymer and styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, Silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Further, a crosslinked styrene resin is also a preferable binder resin.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Monocarboxylic acid having a double bond such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylamide, etc. An acid or a substitute thereof; for example, maleic acid, butyl maleate,
Dicarboxylic acids having a double bond such as methyl maleate, dimethyl maleate and the like and substituted products thereof; for example, vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate and the like; for example, ethylene, propylene, butylene and the like Vinyl monomers such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; Are used alone or in combination.

As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene or the like; for example, ethylene glycol diacrylate , Ethylene glycol dimethacrylate,
Carboxylic esters having two double bonds such as 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinylether, divinylsulfide, divinylsulfone; and compounds having three or more vinyl groups; Can be used alone or as a mixture.

The polymerization method of the high molecular weight component of the resin composition according to the present invention includes an emulsion polymerization method and a suspension polymerization method.

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Further, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
There is an advantage as a method for producing a binder resin for a toner because it is easy to mix with a colorant, a charge control agent and other additives.

However, the resulting polymer tends to be impure due to the added emulsifier, and an operation such as salting out is required to take out the polymer. To avoid this inconvenience, suspension polymerization is advantageous.

In the suspension polymerization, 100 parts by weight or less of the monomer (preferably 1 part by weight) is added to 100 parts by weight of the aqueous solvent.
(0 to 90 parts by weight). Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like. There is an appropriate amount in terms of the amount of a monomer relative to an aqueous solvent, and generally 0.05 to 1 based on 100 parts by weight of an aqueous solvent. Used in parts by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer.

On the other hand, as a method for synthesizing the low molecular weight component of the binder resin according to the present invention, a known method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by polymerizing at a high temperature to reduce the termination reaction rate, but there is a problem that the reaction is difficult to control. In this regard, in the melt polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent and adjusting the amount of the initiator and the reaction temperature. It is preferable to obtain a low molecular weight compound in the resin composition used in the above. Among them, in order to adjust the acid component and the molecular weight to a high degree, for example, a method of obtaining a low molecular weight polymer by mixing polymers having different molecular weights and compositions, a method of post-adding monomers having different compositions, and the like are used. be able to.

As a solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like are used. In the case of a styrene monomer mixture, xylene, toluene or cumene is preferred. It is appropriately selected depending on the polymer to be polymerized.

In the present invention, it is preferable that the toner contains a wax as necessary. The waxes used include paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, and the derivatives include oxides and vinyl monomers. And a graft-modified product.

The wax preferably used in the present invention is
It is represented by the following general formula.

RY

(R represents a hydrocarbon group, Y represents hydrogen, a hydroxyl group, a carboxyl group, an alkyl ether group, an ester group, or a sulfonyl group.

The weight average molecular weight (M
w) is 3000 or less. )

Specific examples of the compounds include: (A) CH ₃ (CH ₂ ) _n CH ₂ OH (n = about 20 to about 30)
0) (B) CH ₃ (CH ₂ ) _n CH ₂ COOH (n = about 20 to about 300) (C) CH ₃ (CH ₂ ) _n CH ₂ OCH ₂ (CH ₂ ) _m CH
₃ (n = about 20 to about 200, m = 0 to about 100) and the like. These compounds are derivatives of the compound (A), and the main chain is a linear saturated hydrocarbon. As long as the compound is derived from the compound (A), those other than those shown in the above examples can be used. By using the above wax, the toner of the present invention can highly satisfy the fixing property at low temperature and the anti-offset property at high temperature.

Among the above compounds, it is particularly preferable to use (A) a high molecular alcohol represented by the formula (A) CH ₃ (CH ₂ ) _n CH ₂ OH (n = about 20 to about 300) as a main component. . The above-mentioned wax has good slip properties and is particularly excellent in offset resistance.

In the present invention, the molecular weight distribution of the wax is measured by GPC (gel permeation chromatography) under the following conditions.

<GPC Measurement Conditions for Wax> Apparatus: GPC-150C (manufactured by Waters) Column: GMH-HT (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (added with 0.1% ionol) ) Flow rate: 1.0 ml / min. Sample: 0.4 ml of 0.15% by weight sample is injected

Measurement is performed under the above conditions, and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample. In addition, Mark-Houw
It is calculated by conversion with a conversion formula derived from the ink viscosity formula.

These waxes are preferably used in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the binder resin.

In the present invention, it is more preferable to add a negative charge control agent to the toner to obtain a negative charge magnetic toner.

Specific examples of the negative charge control agent are described in
1-20153, 42-27596, 44-6
Metal complexes of monoazo dyes described in JP-A Nos. 397 and 45-26478;
No. 38, nitroamine acids and salts thereof, or C.I. I. Dyes and pigments such as 14645;
No. 752, JP-B-58-41508, JP-B-58-7
No. 384, and Zn, A of salicylic acid, naphthoic acid and dicarboxylic acid described in JP-B-59-7385.
Metal complexes such as 1, Co, Cr, Fe, etc., sulfonated copper phthalocyanine pigments, styrene oligomers into which nitro groups and halogens have been introduced, and chlorinated paraffins. In particular, an azo-based metal complex represented by the general formula (1) and a basic organic acid metal complex represented by the general formula (2), which are excellent in dispersibility and effective in stabilizing image density and reducing fog, are preferable.

[0174]

Embedded image

[0175]

Embedded image

Among them, the azo metal complex represented by the formula (1) is more preferable, and the azo iron complex represented by the following formula (3) is most preferable.

[0177]

Embedded image

Next, specific examples of the complex will be shown.

[0179]

Embedded image

[0180]

Embedded image

The content of the charge control agent is preferably from 0.1 to 5 parts by weight, particularly preferably from 0.2 to 3 parts by weight, based on 100 parts by weight of the toner binder resin. If the proportion of the charge control agent is too large, the fluidity of the toner deteriorates and fogging tends to occur. On the other hand, if the proportion is too small, it is difficult to obtain a sufficient charge amount.

[0182]

Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described based on the following embodiments. However, this does not limit the embodiment of the present invention at all. Parts in the examples are parts by weight.

(Inorganic Fine Powder Production Example 1) 40 parts of silica fine powder (specific surface area 110 m ² / g) synthesized by a wet method was treated with 60 parts of dimethyl silicone oil (12,500 cSt) to obtain inorganic fine powder A-1. Obtained.

(Inorganic Fine Powder Production Examples 2 and 3) Inorganic fine powders A-2 and A-3 were obtained in the same manner as in Inorganic Fine Powder Production Example 1.
The formulation and physical properties are shown in Table 1.

(Example of Resin Fine Particles) Table 2 shows the physical properties of the resin fine particles (B-1 to B-3) used in the present invention.

(Second Inorganic Fine Powder Production Example 1) Silica fine powder (specific surface area: 200 m ² / g) synthesized by a dry method 10
0 parts were previously treated with 10 parts of hexamethyldisilazane, and then dimethyl silicone oil (100 c
St) treatment with 10 parts diluted with hexane,
Thereafter, the temperature was raised from room temperature to about 250 ° C., and heat treatment was performed to obtain a second inorganic fine powder C-1.

(Second Inorganic Fine Powder Production Example 2) A second inorganic fine powder C-2 was obtained in the same manner as in the second inorganic fine powder production example 1 except that no treatment was performed with dimethyl silicone oil. Table 3 shows the formulation and physical properties.

<Production Example of Toner Particles> 100 parts of styrene-butyl acrylate-monobutyl maleate copolymer (copolymerization ratio 75/20/5) 100 parts of magnetic iron oxide particles (ψ ₂ = 0.91) 100 parts Azo-based iron complex compound (1) 2 parts shown in the specific examples of the azo-based iron complex • Aliphatic alcohol-based wax (Mw = 700) 4 parts After premixing the above materials, biaxial kneading and extrusion set at 130 ° C. Melt kneading was performed by a machine. The kneaded product was cooled, coarsely pulverized, finely pulverized by a pulverizer using a jet stream, and further classified using an air classifier, and the weight-average particle size was 5.88 μm, and the number% of 2.52 μm or less was 3.5. %,
Thus, toner particles having a number% of 3.17 μm or less and 15.2% were obtained.

<Example 2 of Toner Particle Production> Except that magnetic iron oxide particles having ψ ₂ = 0.65 were used instead of magnetic iron oxide particles (ψ ₂ = 0.91), the procedure was the same as in toner particle production example 1. The weight-average particle diameter is 5.90 μm, the number% of 2.52 μm or less is 3.1%, and the number% of 3.17 μm or less is 15.0.
% Of toner particles were obtained.

<Production Example 3 of Toner Particles>
2. The number% of 41 μm and 2.52 μm or less is 2.1%.
Except that the number% of 17 μm or less was 6.7%, toner particles were obtained in the same manner as in Toner Particle Production Example 1.

<Production Example 4 of Toner Particles>
96%, the number% of 2.52 μm or less is 12.1%,
Except that the number% of 3.17 μm or less was 18.7%, toner particles were obtained in the same manner as in Toner Particle Production Example 1.

Example 1 100 parts of the toner particles of Production Example 1 for toner particles, 0.1 part of inorganic fine powder A-1 and 0.08 part of resin fine particles B-1
0.1 part of the second inorganic fine powder C-1 was mixed with a Henschel mixer to obtain a developer having a porosity of 0.58 at the time of tapping.

Examples 2 to 6 and Reference Examples 1 to 3 As shown in Table 4, the inorganic fine powder, the resin fine particles and the second inorganic fine powder were mixed in the same manner as in Example 1 to obtain a developer.

Comparative Example 1 The magnetic iron oxide used had a sphericity 酸化₂ of 0.52, and the weight-average particle diameter was 12.5 μm, the number% of 2.52 μm or less was 0.1%, and the number% was 3.17 μm or less. % Of toner particles was obtained. 100 parts of the toner particles, 0.1 part of inorganic fine powder A-1 and 1.2 parts of second inorganic fine powder C-1 are mixed with a Henschel mixer, and a developer having a porosity of 0.31 when tapped is used. I got

Comparative Example 2 The sphericity 球₂ of the magnetic iron oxide used was 0.38, the weight-average particle diameter was 8.46 μm, the number% of 2.52 μm or less was 18.7%, and the number% was 3.17 μm or less. % Of the toner particles was 42.3%. 100 parts of the toner particles, 0.1 part of the inorganic fine powder A-1 and the second inorganic fine powder C-1
5 parts and 0.08 part of resin fine particles B-1 were mixed with a Henschel mixer to obtain a developer having a porosity of 0.85 at the time of tapping.

Next, the method for producing the toner carrier used in the present invention will be specifically described. Table 5 shows the physical properties of the spherical particles used in the toner carrier production example and the physical properties of the toner carrier. .

[Toner Carrier Production Example 1] 200 parts of resole type phenol resin solution (containing 50% methanol) 30 parts of graphite having a number average particle size of 1.5 μm 30 parts of conductive carbon black 5 parts of isopropyl alcohol 130 parts Zirconia beads having a diameter of 1 mm were added to the material as media particles, dispersed in a sand mill for 2 hours, and the beads were separated using a sieve to obtain a stock solution (1).

Next, 15 parts of E-1 as conductive spherical particles were added to 380 parts of the stock solution of (1), and the solid content was 32%.
% After adding isopropyl alcohol.
The mixture was dispersed for 1 hour using glass beads having a diameter of 3 mm, and the beads were separated using a sieve to obtain a coating liquid.

Using this coating solution, a coating layer was formed on an aluminum cylindrical tube having an outer diameter of 16 mmφ by a spray method, and then heated and cured at 150 ° C. for 30 minutes in a hot air drying furnace. -1 was produced.

[Toner Carrier Production Example 2] 200 parts of a resol type phenol resin solution (containing 50% methanol) 45 parts of graphite having a number average particle diameter of 6.1 μm 5 parts of conductive carbon black 130 parts of isopropyl alcohol Zirconia beads having a diameter of 1 mm were added to the material as media particles, dispersed in a sand mill for 2 hours, and the beads were separated using a sieve to obtain a stock solution (2).

As the conductive spherical particles, a 11.5 μm spherical PMMA was prepared using a hybridizer (manufactured by Nara Machinery Co., Ltd.).
Spherical conductive resin particles E-2 obtained by coating 100 parts of particles with 5 parts of conductive carbon black were used.

Next, 380 parts of the undiluted solution of (2) was added
A toner carrier D-2 was produced in the same manner as in Production Example 1, except that 10 parts of E-2 was added as conductive spherical particles.

[Toner Carrier Production Example 3] Instead of the conductive spherical particles E-2, 380 parts of the stock solution (2) produced in Production Example 2 was charged with a conductive material having a number average particle size of 11.5 μm. A toner carrier D-3 was produced in the same manner as in Production Example 2, except that 10 parts of spherical PMMA particles E-3 having no toner were added.

[Evaluation] Next, these prepared developers and toner carriers were evaluated by the following methods.

As shown in FIG. 1, 16 commercially available laser beam printers LBP-450 (manufactured by Canon) using a charging roller (11 in the figure) as charging means (A).
4) The printing speed was changed to / min, and the toner carrier D-1 shown in Production Example 1 of the toner carrier was incorporated, and the low temperature and low humidity (10 ° C., 15% RH) and the high temperature and high humidity (32.5 ° C.) , 9
(0% RH) A printout test of 10,000 sheets (10K) was performed in each environment. When the toner was exhausted, a cutout was made in the toner container at the top of the cartridge, and the toner was replenished therefrom to continue the printout test. The obtained images were evaluated for the following items.

(1) Fusion of toner to photoreceptor ：: very good (not generated) ：: good (slight scratches occurred but no effect on image) Δ: normal (fused toner was X: Poor (many fusion of toner and many effects on image)

(2) Poor charging due to contamination of the contact charging member ◎: Very good (no contamination is confirmed by direct visual observation of the charging member) ：: Good (contamination is confirmed by direct visual observation of the charging member, but on the image Δ: Normal (contamination of the charging member appears on the image, but slight) ×: Poor (contamination of the charging member appears on the image, greatly affecting the image)

(3) One-dot reproducibility An independent one-dot pattern was printed out, and the reproducibility of one dot was evaluated by microscopic observation.

：: good (dots are faithfully reproduced) Δ: normal (slightly disturbed in the image) ×: bad (many disturbed images and poor reproducibility)

(4) Image Density After printing out 10,000 sheets (10K), evaluation was performed on ordinary paper for copying machines (75 g / m ² ) by maintaining the image density at the time of printing out. The image density was measured using a “Macbeth reflection densitometer” (manufactured by Macbeth Co., Ltd.) and the density of the original was 0.00
Was measured for the relative density of the white background portion with respect to the printout image.

(5) The whiteness of the transfer paper measured by a fog reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the 10,000 sheets (10
K) Fog was calculated by comparing the solid white after printout with the whiteness of the transfer paper after printing.

Table 6 shows the evaluation results of the above (1) to (5).

[0213]

[Table 1]

[0214]

[Table 2]

[0215]

[Table 3]

[0216]

[Table 4]

[0219]

[Table 5]

[0218]

[Table 6]

Examples 7 to 9 A commercially available laser beam printer LBP-450 (manufactured by Canon) was modified to a print speed of 16 sheets (A4) / 1 minute, and the toner carrier D-1 shown in the toner carrier production example was modified. ~
D-3, low temperature and low humidity (10 ° C, 15% R
H), and a printout test of 50,000 sheets (50K) was performed in each environment of high temperature and high humidity (32.5 ° C., 90% RH). At the time of running out of toner, a cutout was made in the toner container portion at the top of the cartridge, and the toner was replenished therefrom to continue the printout test, and the following items were evaluated.

(1) Image Density Rise In a printout test in each environment, a solid black image was printed at the initial time and at 100 sheets, and the difference in image density was evaluated according to the following criteria.

：: good (density difference is 0.05 or less) Δ: normal (density difference is 0.1 or less) ×: bad (density difference is less than the level of △)

(2) Image density After printing out 10,000 (10K) and 50,000 (50K) sheets in each environment, ordinary paper for copying machines (75 g / m ² )
Was evaluated by maintaining the image density at the time of printout. The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth) with respect to the printout image of a white background portion having a document density of 0.00.

(3) The whiteness of the transfer paper measured by a fog reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the number of 10,000 sheets (10
The fog was calculated from a comparison between the solid white after printing out K) and 50,000 sheets (50K) and the whiteness of the transfer paper after printing.

(4) Fusion of toner to toner carrier After the 50,000-sheet (50K) printout test was completed, the surface of the toner carrier was observed by SEM, and the degree of fusion of the toner was evaluated according to the following criteria.

◎: very good (contamination is not confirmed) ：: good (contamination is slightly confirmed) Δ: normal (partially confirmed contamination) ×: bad (conspicuous contamination is confirmed)

(5) One-dot reproducibility An independent one-dot pattern was printed out, and the reproducibility of one dot was evaluated by microscopic observation.

：: good (dots are faithfully reproduced) Δ: normal (slightly disturbed in the image) ×: bad (many disturbed images and poor reproducibility)

Table 7 shows the evaluation results of the above (1) to (5).

[0229]

[Table 7]

[0230]

According to the present invention, the content of at least resin fine particles and silicone oil or silicone varnish in the toner particles having a specific particle size distribution is 20 to 90% by weight.
By containing the inorganic fine powder of the above, it is possible to obtain an electrostatic image developing toner and an image forming method which are excellent in resolution and high in image density without causing fusion of the toner to the photosensitive member and contamination of the contact charging member.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an image forming apparatus used in an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a molding device for tableting powder.

[Description of Signs] 1 Developing device 2 Developer container 3 Photoreceptor (electrostatic latent image holding member) 4 Transfer unit 5 Laser light or analog light 6 Toner carrier 7 Cleaning blade 8 Regulator blade 11 Charging unit 12 Bias applying unit 13 Developer 14 Cleaning means 15 Magnetic field generation means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G03G 15/08 507 G03G 15/08 507L (72) Inventor Shunji 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Examiner Yuko Fujita (56) References JP-A-3-59567 (JP, A) JP-A-4-50861 (JP, A) JP-A-4-143775 (JP, A) JP-A-5-2284 ( JP, A) JP-A-5-119530 (JP, A) JP-A-6-194943 (JP, A) JP-A-6-230601 (JP, A) JP-A 8-76408 (JP, A) JP-A-8-95298 (JP, A) JP-A-8-179617 (JP, A) JP-A-8-184990 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9 / 08

Claims (33)

(57) [Claims] 1. At least toner particles, resin fine particles ,
(I) an inorganic fine powder containing 20 to 90% by weight of silicone oil or silicone varnish, and (ii) silane
Coupling agent and silicone oil or silicone
It is treated with varnish and has a BET specific surface area of 80 to
A toner for developing an electrostatic image , comprising a second inorganic fine powder having a particle size distribution of 140 m ² / g and a weight average particle diameter (D ₄ ) of X (μ)
m), the number-based particle size of 3.17 μm obtained from the number distribution
When the number% of the following toner particles is Y (number%), X
And Y satisfy the following condition: −5X + 35 ≦ Y ≦ −25X + 180 4.0 ≦ X ≦ 6.3 . 2. The toner according to claim 1, wherein the porosity of the toner obtained from the tap density is 0.45 to 0.70. 3. The electrostatic image developing toner according to claim 1, wherein the toner has a particle size distribution satisfying the following condition: −5X + 35 ≦ Y ≦ −12.5X + 98.75. 4. The toner according to claim 1, wherein the toner has a weight average particle diameter (D).
₄ ) When X is (μm) and the proportion of toner particles having a particle size of 2.52 μm or less in the number distribution of toner is Z (number%), the following condition is satisfied: −7.5X + 45 ≦ Z ≦ −12.0X + 82 the toner according to any one of claims 1 to 3, characterized in that. 5. The inorganic fine powder has a BET specific surface area of 0.0
1~50m a ² / g, The toner according to any one of claims 1 to 4, wherein the amount of silicone oil or silicone varnish is 30 to 85 wt%. 6. The toner according to claim 1, wherein the toner contains a second inorganic fine powder which is treated with a silane coupling agent and a silicone oil or a silicone varnish and has a BET specific surface area of 80 to 140 m ² / g. the toner according to any one of claims 1 to 5,. 7. The resin fine particles are styrene-based organic fine particles, and the styrene-based organic fine particles have a volume resistivity after drying at 40 ° C. of 10 ⁷ to 10 ¹⁴ Ω · cm and an average particle diameter of 0.07 to 10 ¹⁴ Ω · cm.
3 to 1.0 μm, surface area sphericity (ψ ₁ ) 0.9 to 0.9
0.50 and a glass transition point (Tg) of 80 to 1
The toner according to any one of claims 1 to 6, characterized in that a 10 ° C.. 8. The toner sphericity ([psi ₂₎ for developing an electrostatic charge image according to any one of claims 1 to 7, characterized in that a magnetic toner containing a 0.8 or more magnetic iron oxide toner. 9. The second inorganic fine powder contains the second inorganic fine powder.
For 100 parts by weight of powder, silicone oil or silicone oil
It is treated with 1 to 23 parts by weight of corn varnish.
The method according to any one of claims 1 to 8, wherein
The toner for developing an electrostatic image according to the above. 10. An image forming method comprising a step of forming a toner layer on a toner carrier opposite to an electrostatic latent image holding member and developing an electrostatic latent image on the electrostatic latent image holding member.
The toner carrier has at least a substrate and a conductive coating layer, and the surface of the substrate is coated with the conductive coating layer. The toner has at least toner particles, resin fine particles ,
(I) an inorganic fine powder containing 20 to 90% by weight of silicone oil or silicone varnish, and (ii) silane
Coupling agent and silicone oil or silicone
It is treated with varnish and has a BET specific surface area of 80 to
140 m ² / g and a second inorganic fine powder , and the particle size distribution of the toner is such that the weight average particle size (D ₄ ) is X (μ)
m), the number-based particle size of 3.17 μm obtained from the number distribution
When the number% of the following toner particles is Y (number%), X
And Y satisfy the following condition: −5X + 35 ≦ Y ≦ −25X + 180 4.0 ≦ X ≦ 6.3 . 11. The toner according to claim 1, wherein the porosity of the toner determined from the tap density is 0.45 to 0.70.
0. The image forming method according to item 1. 12. The toner according to claim 10, wherein the toner has a particle size distribution satisfying the following condition: −5X + 35 ≦ Y ≦ −12.5X + 98.75.
Or the image forming method according to 11. 13. The toner has a weight average particle diameter (D ₄ ) of the toner X (μm) and a ratio of toner particles having a particle diameter of 2.52 μm or less in the number distribution of the toner Z (number%). Then, the image forming method according to any one of claims 10 to 12, characterized by satisfying the following condition -7.5X + 45 ≦ Z ≦ -12.0X + 82. 14. The inorganic fine powder has a BET specific surface area of 0.1.
01~50m a ² / g, the image forming method according to any one of claims 10 to 13 content of the silicone oil or silicone varnish is characterized in that 30 to 85% by weight. 15. The resin fine particles are styrene-based organic fine particles, and the styrene-based organic fine particles have a volume resistivity after drying at 40 ° C. of 10 ⁷ to 10 ¹⁴ Ω · cm and an average particle size of 0.1 to 10 ¹⁴ Ω · cm.
03-1.0 μm, surface area sphericity (ψ ₁ ) is 0.9
~ 0.50 and a glass transition point (Tg) of 80 ~
The image forming method according to claim 10 , wherein the temperature is 110 ° C. 15 . 16. The toner image forming method according to any one of claims 10 to 15, characterized in that a magnetic toner containing a sphericity (ψ ₂₎ 0.8 or more of the magnetic iron oxide. 17. The conductive coating layer, according to claim 1, wherein at least a number average particle diameter of from the coating by dispersing contain spherical particles 0.3~30μm in the binder resin
An image forming method according to any one of 0 to 16 . 18. The image forming method according to claim 17 , wherein the spherical particles are conductive spherical particles having a true density of 3 g / cm ³ or less. 19. The image forming method according to claim 18 , wherein said spherical particles are carbon particles. 20. The coating amount per unit area of the toner layer formed on the toner carrier is w / ρ = 0.2 to 1.0 w: the toner coating amount per 1 cm ^{2 of the} toner carrier surface (mg) 11. The method according to claim 10 , wherein ρ is set so as to satisfy the true density of the toner (g / cm ³ ), and the average roughness Ra of the surface of the toner carrier is 1.8 or less.
20. The image forming method according to any one of claims 1 to 19 . 21. The second inorganic fine powder is the second inorganic fine powder.
For 100 parts by weight of fine powder, silicone oil or silicone oil
Being treated with 1 to 23 parts by weight of corn varnish
21. The method according to claim 10, wherein
An image forming method according to any one of the preceding claims. 22. A charging step in which a charging member to which a voltage is applied from the outside is brought into contact with the electrostatic latent image holding member to perform charging, and a toner layer is formed on the toner carrier facing the electrostatic charging latent image holding member. Forming an electrostatic latent image on the latent electrostatic image holding member, wherein the toner carrier has at least a substrate and a conductive coating layer, and the surface of the substrate is electrically conductive. Coated with a coating layer, wherein the toner comprises at least toner particles, resin fine particles ,
(I) an inorganic fine powder containing 20 to 90% by weight of silicone oil or silicone varnish; and (ii) silane.
Coupling agent and silicone oil or silicone
It is treated with varnish and has a BET specific surface area of 80 to
140 m ² / g and a second inorganic fine powder , and the particle size distribution of the toner is such that the weight average particle size (D ₄ ) is X (μ)
m), the number-based particle size of 3.17 μm obtained from the number distribution
When the number% of the following toner particles is Y (number%), X
And Y satisfy the following condition: −5X + 35 ≦ Y ≦ −25X + 180 4.0 ≦ X ≦ 6.3. 23. The toner according to claim 2, wherein the porosity of the toner determined from the tap density is 0.45 to 0.70.
3. The image forming method according to item 2. 24. The toner according to claim 22, wherein the toner has a particle size distribution satisfying the following condition: −5X + 35 ≦ Y ≦ −12.5X + 98.75.
Or the image forming method according to 23. 25. In the toner, the weight average particle diameter (D ₄ ) of the toner is X (μm), and the ratio of toner particles having a particle diameter of 2.52 μm or less in the number distribution of the toner is Z (number%). Then, the image forming method according to any one of claims 22 to 24, characterized by satisfying the following condition -7.5X + 45 ≦ Z ≦ -12.0X + 82. 26. The inorganic fine powder has a BET specific surface area of 0.1.
The image forming method according to any one of claims 22 to 25 , wherein the content is from 0.1 to 50 m ² / g, and the content of silicone oil or silicone varnish is from 30 to 85% by weight. 27. The resin fine particles are styrene-based organic fine particles, and the styrene-based organic fine particles have a volume resistivity after drying at 40 ° C. of 10 ⁷ to 10 ¹⁴ Ω · cm and an average particle diameter of 0.1 to 10 ¹⁴ Ω · cm.
03-1.0 μm, surface area sphericity (ψ ₁ ) is 0.9
~ 0.50 and a glass transition point (Tg) of 80 ~
The image forming method according to any one of claims 22 to 26 , wherein the temperature is 110 ° C. 28. The toner image forming method according to any one of claims 22 to 27, characterized in that a magnetic toner containing a sphericity (ψ ₂₎ 0.8 or more of the magnetic iron oxide. 29. The conductive coating layer, according to claim 2 wherein at least a number average particle diameter in the binder resin is characterized by comprising the film obtained by dispersing contain spherical particles 0.3~30μm
29. The image forming method according to any one of 2 to 28 . 30. The image forming method according to claim 29 , wherein the spherical particles are conductive spherical particles having a true density of 3 g / cm ³ or less. 31. The image forming method according to claim 30 , wherein the spherical particles are carbon particles. 32. A coating amount per unit area of a toner layer formed on the toner carrier is w / ρ = 0.2 to 1.0 w: a toner coating amount (mg / cm ² ) of the toner carrier surface 23. The method according to claim 22 , wherein ρ is set so as to satisfy a true density of the toner (g / cm ³ ), and an average roughness Ra of the surface of the toner carrier is 1.8 or less.
Or image forming method according to any one of 31. 33. The second inorganic fine powder is the second inorganic fine powder.
For 100 parts by weight of fine powder, silicone oil or silicone oil
Being treated with 1 to 23 parts by weight of corn varnish
34. Any of claims 22 to 33, characterized in that
An image forming method according to any one of the preceding claims.