JPH09146295A - Developing method and toner for electrophotography - Google Patents

Abstract

(57) Abstract: Development comprising a developing roll having a silicone rubber on at least a surface portion thereof, and a blade for imparting an electric charge while uniformly controlling the thickness of a toner layer formed on the developing roll. In a non-magnetic one-component developing method in which a toner image is formed using a device while contacting a photoconductor with the developing roll, a non-magnetic one-component toner having inorganic fine particles hydrophobized with silicone oil externally added to the surface is used. A developing method characterized by being used, and an electrophotographic toner used in the developing method. According to the developing method of the present invention, in a non-magnetic one-component developing method in which a developing roll and a photosensitive member are in contact with each other, even when a developing roll having at least a surface of silicone rubber is used, the photosensitive drum is contaminated by residual silicone oil. Can be reduced. The electrophotographic toner of the present invention is preferably used in the developing method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like, and more specifically, a non-magnetic one-component developing method by a contact method and The present invention relates to an electrophotographic toner used.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat.
No. 221776, No. 2297691, No. 2357
As described in the specification such as 809, the photoconductive insulating layer is uniformly charged (charging step), and then the layer is exposed (exposure step) to dissipate the charge in the exposed portion. An electrostatic latent image is formed thereon, and a colored charged fine powder called toner is made to adhere to the electrostatic latent image so as to be visualized (development step). After the image is transferred onto a transfer material (transfer step), the image is permanently fixed by heating, pressure or other appropriate means (fixing step). After the transfer of the toner image, the residual toner on the photoconductor is scraped off to clean the photoconductor surface (cleaning step).

Of these, in the developing step, toner and
The two-component magnetic brush developing method using a developer consisting of two components, that is, a carrier used to impart an electric charge to the toner and to convey the toner to the electrostatic latent image portion by magnetic force, has been most conveniently used conventionally.

However, in the two-component magnetic brush developing method, a magnet is required in the developing roll because a magnetic force is used to transport the developer, and the carrier is also a metal such as iron powder, nickel powder, ferrite or an oxide thereof. Therefore, the developing machine and the developer become heavy, which hinders a reduction in size and weight of the recording apparatus.

[0005] For example, see US Pat. No. 3,909,258.
No. 4,121,931, a magnetic substance is included inside the toner without using a carrier,
A magnetic one-component developing method in which the toner is transported to the electrostatic latent image portion by the magnetic force of the toner has been often used. However, this developing method also requires a magnet inside the developing roll, which is disadvantageous from the viewpoint of reducing the weight of the developing device.

In order to solve the above-mentioned problems of these developing methods, US Pat.
No. 2, JP-B-41-9475, and JP-B-45-2877.
And non-magnetic one-component developing methods using only toners containing no magnetic powder described in JP-A-54-3624 and the like, have been actively studied and improved. This developing method is very advantageous in reducing the size and weight of the recording apparatus in that a magnet is not used for the developing roll. In particular, this type of developing method is increasingly used for small personal printers and plain paper Fax which have been actively developed in recent years.

Such a non-magnetic one-component developing method further includes a contact method and a non-contact method. In the contact method, an elastic body for adhering toner to a photoconductor holding an electrostatic latent image is used as a surface. The developing roll included in 1. is used. Urethane rubber, silicone rubber, natural rubber and copolymers containing ethylene and propylene are used for this developing roll. Among them, silicone rubber is widely used because of its easy hardness adjustment and low cost. It is used.

However, the amount of residual silicone oil in silicone rubber is very large, and in the case of the developing method in which the developing roll is in direct contact with the photosensitive member, the silicone oil contaminates the photosensitive member and the image in that portion is whitened. Some problems have been pointed out. Specifically, if printing is performed after the device is left without being operated, there is a problem in that the image of the contact portion is whitened due to contamination at the beginning and the whitening does not disappear immediately after repeated printing. It was

Therefore, conventionally, the amount of residual silicone oil has been reduced by a method such as reheating after molding the developing roll, or the contamination of the photoreceptor has been reduced by a method of providing another rubber layer on the upper layer of the silicone rubber. .

However, the residual silicone oil cannot be completely removed by reheating, and when another rubber layer is provided, it is difficult to use because the advantage of the silicone rubber roll cannot be exhibited.

Therefore, in the developing device in which the developing roll and the photosensitive member are in contact with each other, it is expected by those skilled in the art to develop a developing method capable of reducing such contamination of the photosensitive member, but it has not been found yet. The reality is that there is none.

[0012]

Therefore, an object of the present invention is to provide a non-magnetic one-component developing method in which a developing roll and a photosensitive member are in contact with each other, even when a developing roll having a silicone rubber on at least a surface portion is used. It is an object of the present invention to provide a developing method capable of reducing the contamination of a photoreceptor with silicone oil, and an electrophotographic toner used in the developing method.

[0013]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, by using a toner to which inorganic fine particles having been subjected to a specific hydrophobization treatment are added, a photosensitive oil by silicone oil is used. It was found that it is possible to reduce body contamination, and further studies were conducted to complete the present invention.

That is, conventionally, inorganic fine particles have been externally added to the toner surface as a fluidizing agent. In particular, inorganic fine particles hydrophobized with silicone oil are externally added to the toner surface to release from the developing roll. It has been found that it is possible to adsorb the used silicone oil and reduce the contamination of the photoreceptor.

That is, the gist of the present invention is (1) a developing roll having silicone rubber on at least a surface portion thereof, and a blade for imparting an electric charge while uniformly controlling the thickness of a toner layer formed on the developing roll. In a non-magnetic one-component developing method in which a toner image is formed while bringing a photoconductor into contact with the developing roll by using a developing device including a non-magnetic material, inorganic fine particles hydrophobized with silicone oil are externally added to the surface. A developing method characterized by using a one-component toner, (2) the developing method according to (1) above, wherein the inorganic fine particles are silica fine particles, and (3) the average particle diameter of primary particles of the inorganic fine particles is 30 nm or more and 100 nm or less. The developing method according to (1) or (2) above, wherein (4) the amount of silicone oil added to the inorganic fine particles in the hydrophobic treatment is
The developing method according to any one of (1) to (3) above, wherein the surface area of the inorganic fine particles is ² to 3 mg / m ² , and (5) the toner coverage with the inorganic fine particles is 30% or more (1) to (4) The developing method according to any one of (6), wherein the non-magnetic one-component toner has a polyester resin having an acid value of AV and a hydroxyl value of OHV as a main component of the binder resin,
The developing method according to any one of (1) to (5) above, which uses a polyester resin having an OHV / AV value of 1.2 or more, (7) the polyester resin is represented by the following general formula (I).

[0016]

Embedded image

(In the formula, R ¹ represents an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the sum of the average values thereof is 2 to 16). And the following general formula (II) or (III)

[0018]

Embedded image

1 to 50 mol% of a divalent carboxylic acid represented by the formula (wherein R ² and R ³ are the same or different and each represents a hydrocarbon group having 4 to 20 carbon atoms) or an anhydride thereof. , And 10 parts of trimellitic acid or its acid anhydride
The developing method according to (6) above, which is a polyester resin obtained by polycondensation with an acid component contained in an amount of 30 mol%.
(8) The developing method according to (6) or (7) above, wherein the polyester resin has a glass transition point of 55 ° C. or higher.
The present invention relates to an electrophotographic toner used in the developing method according to any one of (1) to (8).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The developing method of the present invention comprises a developing roll having a silicone rubber on at least a surface portion thereof, and a blade for imparting an electric charge while controlling the thickness of a toner layer formed on the developing roll to a constant value. In a non-magnetic one-component developing method in which a toner image is formed while bringing a photoconductor into contact with the developing roll by using a developing device including a non-magnetic material, inorganic fine particles hydrophobized with silicone oil are externally added to the surface. It is characterized by using a one-component toner. First, the toner used in the present invention will be described.

The toner (electrophotographic toner of the present invention) used in the present invention is a non-magnetic one-component toner in which inorganic fine particles which have been hydrophobized with silicone oil are externally added to the surface.

As the silicone oil used for the hydrophobizing treatment, dimethyl silicone oil having a viscosity of 50 to 10,000 cS at 25 ° C., methylphenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, Polyether modified silicone oil, alcohol modified silicone oil, amino modified silicone oil,
Epoxy-modified silicone oil, epoxy / polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, and the like can be used.

The average particle size of the primary particles of the inorganic fine particles treated with silicone oil is preferably 30 nm or more and 100 nm or less, and more preferably 30 nm or more and 70 nm or less. If it is smaller than this range, the inorganic fine particles tend to be buried in the toner during use of the toner, and the effect is difficult to last. If it is larger than this range, the adverse effects such as the inorganic fine particles easily scratching the surface of the photoreceptor tend to be large. Here, the average particle diameter is a number average particle diameter.

The particle size of the inorganic fine particles used in the present invention can be measured by a particle size distribution measuring device utilizing dynamic light scattering. Since it is difficult to dissociate secondary aggregation of particles, scanning It is best to determine the particle size from photographs taken with a scanning electron microscope or a transmission electron microscope. As another index, the inorganic fine particles have a true specific gravity of 2.3 g /
In the case of silica of cm ² , the BET specific surface area is 20 to 80 m ^2.
/ G corresponds to the above particle size.

As the inorganic fine particles, conventionally known materials can be used. For example, silicon dioxide (silica),
Examples thereof include titanium dioxide (titania), aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide, and the like, and silica fine particles are particularly preferable.

Specific examples of those preferably used in the present invention include MOX80 (average particle size, about 30 nm), OX50 (average particle size, about 40 n) manufactured by Nippon Aerosil Co., Ltd.
m) and TT600 (average particle size, about 40 nm), manufactured by Idemitsu Kosan, IT-PB (average particle size, about 40 nm) and IT-PC (average particle size, about 60 nm), Fuji Titanium Industry Co., Ltd., TAF110A ( Average particle size, about 40-50n
m) and TAF510 (average particle size, about 40 to 50 n)
m) etc. can be conveniently used. These inorganic particles are
When used as an electrophotographic toner, they may be used alone or in combination of two or more.

In the present invention, the amount of silicone oil added to the inorganic fine particles in the hydrophobic treatment is preferably ¹ to 5 mg / m ² per surface area of the inorganic fine particles,
More preferably, it is 2-3 mg / m ² . If it is less than this range, the effect on the contamination of the photoconductor tends to be small, and if it is more than this range, the cohesiveness of the inorganic fine particles becomes strong, and it tends to be impossible to uniformly adhere to the toner surface. Such an added amount has a BET specific surface area of 5
In the case of 0 m ³ / g of inorganic fine particles, this corresponds to 10 to 15 parts by weight per 100 parts by weight of inorganic fine particles.

The surface area of the inorganic fine particles here means the BET specific surface area, which can be measured by using a commercially available nitrogen adsorption BET specific surface area measuring device, for example, manufactured by Shimadzu Corporation. A flow-type specific surface area automatic measuring device (flow soap 2300 type) or the like can be used.

In the present invention, within the range that does not impair the effects of the present invention, the above-mentioned inorganic fine particles are surface-treated with known inorganic fine particles not subjected to surface treatment and / or a hydrophobic treatment agent other than silicone oil. One or more kinds of known inorganic fine particles may be used in combination.

The method of hydrophobizing treatment with silicone oil is not particularly limited as long as the silicone oil is adsorbed on the surface of the inorganic fine particles. For example, while stirring the raw material of the inorganic fine particles in the mixing tank, the silicone oil is used as a solvent. And diluting and spraying, and heating and drying in a tank for a certain time while continuing stirring.

The non-magnetic one-component toner of the present invention is obtained by externally adding the above-mentioned hydrophobically treated inorganic fine particles to the surface. The untreated toner is at least a binder resin, a colorant, and a charge. The toner contains a control agent, and any conventional non-magnetic one-component toner for electrophotography can be used.

Examples of the binder resin include styrenes such as styrene, chlorostyrene and α-methylstyrene: ethylene,
Propylene, butylene, isobutylene and other monoolefins: vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate and other vinyl esters: methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, dodecyl acrylate, Phenyl acrylate,
Esters of α-methylene aliphatic monocarboxylic acids such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and dodecyl methacrylate: vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether: vinyl methyl ketone, vinyl hexyl Examples thereof include homopolymers or copolymers of vinyl ketone and the like such as ketone and vinyl isopropenyl ketone.

Furthermore, natural and synthetic waxes, polyester, polyamide, epoxy resin, polycarbonate, polyurethane, silicone resin, fluorine resin,
Petroleum resin and the like can be used, but in the present invention, polyester resin is preferably used.

In the polyester resin, a carboxyl group and / or a hydroxyl group is present at the molecular end of the polyester unless transesterification or reaction of a monovalent carboxylic acid and / or alcohol is carried out. Depending on the amount of the end group, the polyester resin is present. It has been confirmed that the amount of triboelectricity of itself changes. That is, in the amount of the terminal group, particularly when the acid value is excessively reduced, the triboelectric charge amount of the polyester resin is decreased, and conversely, when the acid value is excessively increased, the triboelectric charge amount of the polyester resin is increased to a certain level. The environmental dependency after toner formation becomes remarkable, and it becomes difficult to use it as a toner.

Therefore, the acid value is 5 to 60 (KOHmg /
The polyester resin shown in g) is generally used for toner. In the present invention, when the acid value of the polyester resin is AV and the hydroxyl value is OHV, OHV
A polyester resin having a value of / AV of 1.2 or more is preferable. The reason for this is that the toner containing a polyester resin having an OHV / AV value of 1.2 or more has a good fluidity, although the reason has not been clarified yet. It is preferably used because it can be lowered. Where AV and OHV
Is measured by the method specified in JIS K 0070. In this case, when the ethyl acetate insoluble content is 3.0% by weight or more, it is preferable to use dioxane as the acid value measuring solvent. The value of OHV / AV of 1.2 or more can be easily obtained by using a larger amount of the entire alcohol component than the total carboxylic acid component in the co-condensation reaction with respect to the number of functional groups (Japanese Patent Laid-Open No. 195677/1987). 62-1956
78, 63-68849, 63-68.
850, 63-163469, and Japanese Patent Laid-Open No.
-155362 gazette etc.).

The polyester resin used in the present invention is
Alcohol and carboxylic acid, or carboxylic acid ester, carboxylic acid anhydride, etc. are used as raw material monomers.

Examples of the dihydric alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (3.
3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2
Alkylene oxide adducts of bisphenol A such as -bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedi methanol,
Examples include dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A and the like.

Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,
4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-
Butanetriol, 1,2,5-pentanetriol,
Glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like can be mentioned.

The acid component is a carboxylic acid component and is a divalent monomer such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid,
Alkenyl succinic acid or alkyl succinic acid such as succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or n-dodecenyl succinic acid, n-dodecyl succinic acid, anhydrides of these acids, lower alkyl (C1 to C
4) Esters and other divalent carboxylic acids can be mentioned.

As the trivalent or higher carboxylic acid component, 1,
2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,2
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,
2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimer acid, and anhydrides of these acids, lower alkyl (C1 ~ C
4) Esters and the like can be mentioned.

Among them, polyester resin is particularly preferable. (A) The following general formula (I)

[0042]

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(In the formula, R ¹ represents an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the sum of their average values is 2 to 16). And (b) the following general formula (II) or (III)

[0044]

[Chemical 6]

(In the formula, R ² and R ³ are the same or different and each represents a hydrocarbon group having 4 to 20 carbon atoms.) 1 to 50 mol of a divalent carboxylic acid or its acid anhydride %, And a polyester resin obtained by condensation polymerization with an acid component containing 10 to 30 mol% of trimellitic acid or its acid anhydride.

The glass transition point of the polyester resin used in the present invention is usually 55 ° C. or higher, preferably 6
0 ° C. or higher. In the non-magnetic one-component developing method, the toner is considerably stressed by the charging blade, so that durability is not maintained against stress at less than 55 ° C., which is not preferable.

The polyester resin used in the present invention is
Usually, it can be produced by polycondensing a polyol component and a polycarboxylic acid component in an inert gas atmosphere at a temperature of 180 ° C to 250 ° C. In this case, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, etc. can be used.

As the colorant used in the toner, carbon black: C.I. I. Pigment Yellow 1, 3, 74, 97, 98 etc. acetoacetate arylamide monoazo yellow pigments: C.I. I. Pigment
Acetoacetic acid arylamide-based disazo yellow pigments such as yellow 12, 13, 13, and 17; I. Solvent Yellow 19, 77, 79, C.I. I. Yellow dyes such as Disperse Yellow 164: C.I. I. Pigment Red 48, the same 49: 1, the same 53: 1, the same 57, the same 57: 1, the same 81, the same 122, the same 5 and the like red or red pigments: C.I. I. Red dyes such as Solvent Red 49, 52, 58 and 8: C.I. I. Pigment Blue 15: 3 and the like, a blue-based dye / pigment of copper phthalocyanine and its derivative: C.I. I. Pigment Green, the same as 36 (Phthalocyanine Green), and other green pigments can be used. These dyes and pigments may be used alone or in combination of two or more.

The toner of the present invention may contain a charge control agent, and as the charge control agent which can be used, for negatively charged toner, chromium / azo complex dye, iron azo complex dye, cobalt / azo complex dye can be used. , Chromium / zinc / aluminum / boron complex or salt compound of salicylic acid or its derivative, chrome / zinc / aluminum / boron complex or salt compound of naphtholic acid or its derivative, chrome / zinc of benzylic acid or its derivative
Surface active agents such as aluminum / boron complex or salt compound, long-chain alkyl carboxylate, and long-chain alkyl sulfonate are used for positively charged toner in nigrosine dye and its derivative, triphenylmethane derivative, tetraphenylmethane derivative and tetraphenylmethane derivative. Examples thereof include derivatives such as quaternary ammonium salt, quaternary phosphonium salt, quaternary pyridinium salt, guanidine salt and amidine salt.

In producing the toner used in the present invention,
A property improving agent such as a wax such as a polyolefin is added as an offset preventing agent, but when the polyester resin according to the present invention is used as a binder resin, it is not necessary to add various property improving agents, However, the addition amount is small.

As a method for producing the toner of the present invention, conventionally known production methods such as a kneading and pulverizing method, a spray dry method and a polymerization method can be used. For example, as a general example, first, a resin, a colorant, a wax, a charge control agent, etc. are uniformly dispersed and mixed in a known mixer, and then the mixture is sealed in a closed kneader or a single-screw or twin-screw extruder. Melt kneading,
After cooling, it may be crushed and classified. In recent years, single-screw or twin-screw extruders have become the mainstream because of their advantages such as continuous production. For example, KTK twin-screw extruders manufactured by Kobe Steel, TEM extruders manufactured by Toshiba Machine Co., Ltd. A twin screw extruder manufactured by CK Corporation, a PCM type twin screw extruder manufactured by Ikegai Iron Works, or a kneader manufactured by Bus is preferably used.

The average particle size of the toner thus obtained is usually 20 μm or less, and the average particle size is 3 to 2
0 μm is preferred. The average particle size here is a volume average particle size.

In the toner of the present invention, the aforementioned inorganic fine particles are externally added to the surface of the toner. Such an external addition treatment is carried out by using a classified toner and externally added inorganic fine particles in a super mixer, It is sufficient to stir and mix with a high speed stirrer such as a Henschel mixer. The mixing conditions such as the number of rotations and the mixing time for stirring may be determined as appropriate in accordance with the toner performance. It is more preferable that the inorganic fine particles be subjected to a crushing treatment in advance.

At this time, the coverage of the toner with the inorganic fine particles is preferably 30% or more, more preferably 30 to 60%. If it is smaller than this range, the effect of preventing contamination of the photoreceptor tends to be insufficient. However, when silica, for example, is added to the toner as the inorganic fine particles in the present invention, the silica actually adheres to the toner surface in a partially aggregated state, so that the actual coverage is low.

Therefore, it is assumed that the coverage f in the present invention is calculated by the following equation. f (%) = {3 / 2π × (D · ρτ) / (d · ρs) ×
C × 100 (wherein, the particle size of the inorganic particles is d, the particle size of the toner is D, ρt and ρs are the true specific gravities of the toner and the inorganic particles, respectively, and C is the weight ratio of the inorganic particles / the toner. .)

The developing method of the present invention is characterized by using the toner as described above. The developing roll having a silicone rubber on at least the surface thereof and the thickness of the toner layer formed on the developing roll. This is a non-magnetic one-component developing method in which a toner image is formed while a photoconductor and the developing roll are brought into contact with each other by using a developing device equipped with a blade that applies a charge while regulating the thickness to a constant value.

That is, the developing method of the present invention is classified into a non-magnetic one-component developing method by a contact developing method, which comprises a developing roll having at least a surface portion of silicone rubber which is an elastic body, and the developing roll. The developing device is provided with a blade that applies an electric charge while controlling the thickness of the toner layer formed on the upper surface to a constant value. The developing method of the present invention will be described below with reference to the drawings of the developing device.

FIG. 1 is a sectional view showing an example of a developing device used in the present invention. 1 is a developing roll,
It has a silicone rubber which is an elastic body on at least the surface portion. In the developing device of FIG. 1, the silicone rubber layer 2 is provided on the surface of the rotating shaft roll, and the elastic stress of the silicone rubber layer 2 causes the developing roll and the photoconductor to come into pressure contact with each other. Reference numeral 3 denotes a blade, which has a particular shape and material (the triboelectric series needs to be considered) as long as the blade imparts electric charge while regulating the thickness of the toner layer formed on the developing roll to a constant value. Not limited. Also, the number is preferably three or more, but one is sufficient. In addition,
In the case of the above toner, the blade material is metal (SUS
Etc.), urethane rubber, silicone rubber and the like are preferable. 4
Is a photoconductor, and an ordinary inorganic photoconductor or organic photoconductor used in the contact type non-magnetic one-component developing method is used. 5
Is the above-mentioned toner, 6 is a charged toner, and 7 is a developing toner.

The developing process will be described in order. First, the toner 5 is conveyed in the direction of the arrow by the rotation of the developing roll 1, but the thickness of the toner layer is regulated to a constant value by the blade 3 and an electric charge is applied. . The toner layer formed by passing through the blade 3 is composed of the charged toner 6, and is separated from the developing roll 1 by electrostatic attraction due to the electrostatic latent image formed on the photoconductor 4, and the toner image composed of the developing toner 7 is formed. Is formed on the photoreceptor. In the above development process,
A bias voltage may be applied by a known method. For details of the developing process, reference can be made to U.S. Pat. No. 3,731,146.

[0060]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples and the like. It should be noted that "parts" shown in the examples all represent parts by weight. In the present invention, the glass transition point (Tg) of the obtained resin is measured by a differential scanning calorimeter, and the conditions were as follows.

<Measurement of glass transition point> Using a differential scanning calorimeter (manufactured by Seiko Denshi Kogyo Co., Ltd.), the temperature was raised to 100 ° C. and left at that temperature for 3 minutes, and then the temperature lowering rate was 10 ° C. /
min. The sample cooled to room temperature at
° C / min. The glass transition point (Tg) is the temperature at the intersection of the extension line of the baseline below the glass transition temperature and the tangent line showing the maximum slope between the rising portion of the peak and the apex of the peak when measured at .

Resin Production Example Polyoxypropylene (2.2) -2,2-bis (4-)
Hydroxyphenyl) propane 714 g, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 663 g, isophthalic acid 518 g, isooctenyl succinic acid 70 g, 1,2,4-benzenetricarboxylic acid 80 g, and 2 g of dibutyltin oxide was placed in a glass 3-liter four-necked flask, equipped with a thermometer, a stainless stir bar, a downflow condenser, and a nitrogen introduction tube, and was placed under a nitrogen stream in a mantle heater under a nitrogen stream.
The reaction was allowed to proceed with stirring at 0 ° C. The degree of polymerization is ASTME
The softening point according to 28-51T was followed and the reaction was terminated when the softening point reached 130 ° C. The obtained resin was a pale yellow solid and had a glass transition temperature of 65 ° C. The acid value of the resin was 18 KOHmg / g and the hydroxyl value was 35 KOHmg / g. This resin is referred to as a binder resin (1).

Preparation of untreated toner Binder resin (1) 100 parts by weight Carbon black 8 parts by weight Brand name: "Regal 330R" (manufactured by Cabot) Charge control agent 1 part by weight Brand name: "S-34" (Orient Wax 2 parts by weight Product name: "Viscor 550P" (manufactured by Sanyo Chemical Co., Ltd.)

After thoroughly mixing the materials having the above composition with a Henschel mixer, kneading with a twin-screw extruder, cooling and coarsening, pulverizing with a jet mill, and further classifying with a wind classifier, and averaging An untreated toner having a particle size of 10 μm was obtained.

Examples 1 to 5 and Comparative Examples 1 to 3 The inorganic fine particles externally added to the toner surface are obtained by treating the inorganic fine particle raw materials listed in Table 1 with silicone oil or the like. Toner surface treatment is based on toner base 1
It was carried out by adding 1.0 part of inorganic fine particles to 00 parts so that the coating rate would be 30% or more, and mixing with a Henschel mixer. In this way, a toner used for image evaluation was prepared.

[0066]

[Table 1]

The hydrophobic treatment of the inorganic fine particles was performed as follows. (1) 100 parts of inorganic fine particle raw material is stirred in a mixing tank. (2) A necessary amount of the treating agent is diluted with a solvent and sprayed on the inorganic fine particles in the mixing tank. (3) While continuing stirring, the temperature inside the tank is raised to 105 ° C. and maintained for 2 hours. (4) Remove after cooling.

The toners of Examples 1 to 5 and Comparative Examples 1 to 3 obtained as described above were used in a non-magnetic one-component system in which a developing roll made of silicone rubber was brought into direct contact with the electrostatic latent image on the photoreceptor. Using an electrophotographic recording apparatus (in FIG. 1, the blade was composed of a SUS plate and the stress due to the bending was used), the contamination of the silicone oil on the photoreceptor was evaluated as follows. Table 2 shows the results.

Toner is put in the developing tank, and halftone dots are printed on the entire surface to confirm that there is no white spot due to contamination of silicone oil (when the silicone oil adheres to the photoconductor and is white spot). But it disappears after printing about 10 sheets). It is left for 36 hours in a state where the developing tank is set in the apparatus (a state where the developing tank and the photosensitive member are pressure-bonded). The printing of halftone dots on the entire surface is continuously performed on 20 sheets and the state of white spots is observed.

[0070]

[Table 2]

As is clear from Table 2, in Examples 1 to 5 in which the inorganic fine particles surface-treated with silicone oil were externally added to the toner, the occurrence of white spots was slight and the disappearance was rapid. On the other hand, Comparative Example 1 in which no external additive was added
In Comparative Example 2 in which an external additive hydrophobized with hexamethyldisilazane was used, the occurrence of white spots was remarkable and the disappearance was slow. On the other hand, in Comparative Example 3 in which silica particles not subjected to the hydrophobizing treatment were externally added to the toner, as shown in the results of Table 2, there was an effect on white spots, but fog was generated due to the low charge amount of the toner. It has been found that there is a problem that the amount of charge of the toner extremely decreases under high temperature and high humidity. From the above results, it is considered that by externally adding the inorganic fine particles that have been hydrophobized with silicone oil to the toner surface, the silicone oil released from the developing roll can be adsorbed to reduce the contamination of the photoconductor.

[0072]

According to the developing method of the present invention, in a non-magnetic one-component developing method in which a developing roll and a photosensitive member are in contact with each other, even when a developing roll having at least a surface portion of silicone rubber is used, it is exposed to a residual silicone oil. Body pollution can be reduced. The electrophotographic toner of the present invention is preferably used in the developing method.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a developing device used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Development roll 2 Silicone rubber layer 3 Blade 4 Photoconductor 5 Toner 6 Charged toner 7 Developed toner

Claims (9)

[Claims] 1. A developing device equipped with a developing roll having silicone rubber on at least a surface portion thereof, and a blade for imparting an electric charge while controlling a thickness of a toner layer formed on the developing roll to a constant value. In a non-magnetic one-component developing method in which a toner image is formed while a body is brought into contact with the developing roll, a non-magnetic one-component toner having inorganic fine particles hydrophobized with silicone oil externally added to the surface is used. And developing method. 2. The developing method according to claim 1, wherein the inorganic fine particles are silica fine particles. 3. The average particle diameter of the primary particles of the inorganic fine particles is 30.
3. The developing method according to claim 1, which has a size of from 100 nm to 100 nm. 4. The developing method according to claim 1, wherein the amount of silicone oil added to the inorganic fine particles in the hydrophobic treatment is 2-3 mg / m ² per surface area of the inorganic fine particles. 5. The coverage of the toner with the inorganic fine particles is 30.
% Or more, and the developing method according to claim 1. 6. A polyester resin in which a non-magnetic one-component toner has an OHV / AV value of 1.2 or more when the acid value of the polyester resin is AV and the hydroxyl value is OHV as the main component of the binder resin. The developing method according to claim 1, wherein the developing method is used. 7. A polyester resin has the following general formula (I): (In the formula, R ¹ represents an alkylene group having 2 to 4 carbon atoms,
x and y are positive integers, and the sum of respective average values is 2 to 16
It is. ) And the following general formula (II) or (III) (In the formula, R ² and R ³ are the same or different and each represents a hydrocarbon group having 4 to 20 carbon atoms.) 1 to 50 mol% of a divalent carboxylic acid or its anhydride, and tri The developing method according to claim 6, which is a polyester resin obtained by polycondensation of an acid component containing 10 to 30 mol% of mellitic acid or an acid anhydride thereof. 8. The glass transition point of the polyester resin is 55.
The developing method according to claim 6 or 7, which has a temperature of not less than ° C. 9. An electrophotographic toner used in the developing method according to claim 1.