JPH03107866A - Image forming method - Google Patents

Abstract

PURPOSE:To prevent the white line-like image voids occurring in the scratching flaws of an org. photosensitive layer by using a polyester resin obtd. by bringing a monomer compsn. contg. specific compsn. into polycondensation reaction. CONSTITUTION:The polyester resin obtd. by bringing the monomer compsn. contg. aliphat. diol, arom. dicarboxylic acid and trivalent or higher valency polyol into polycondensation reaction is used. Positive chargeability is imparted to the toner itself by using the trivalent or higher valency polyol. The impact energy of a magnetic brush is relieved by using the aliphat. diol and further making combination use of the arom. dicarboxylic acid and the trivalent or higher valency polyol. The images having the good image quality are stably formed over many times in this way without generating the white line-like image voids occurring in the scratching flaws of the org. photosensitive layer, the black line-like stains by a cleaning defect and the white line-like sweeping seams occurring in the magnetic brush.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method applied in electrophotography, electrostatic recording, electrostatic printing, and the like.

[Conventional technology]

At present, as a method for forming a visible image from certain image information, methods using electrostatic latent images, such as electrophotography, electrostatic recording, and electrostatic printing, are widely used.

For example, in electrophotography, a photoreceptor having a photosensitive layer made of a photoconductive material is given a -like electrostatic charge, and then imagewise exposure causes the surface of the photoreceptor to have an electrostatic charge corresponding to the original. A latent image is formed, and this electrostatic latent image is developed with a developer to form a toner image. This toner image is transferred to a recording material such as paper and then fixed by heating, pressure, etc. to form a copy image. On the other hand, after the transfer process, the photoreceptor is neutralized, toner remaining on the photoreceptor without being transferred is cleaned, and then the photoreceptor is used for forming the next copy image.

As a method for developing an electrostatic latent image, a magnetic brush developing method is conventionally known. In this magnetic brush development method, a magnetic material contained in the developer causes the developer to stand on the developer carrier to form a magnetic brush, and this magnetic brush rubs the surface of the photosensitive layer of the photoreceptor to remove the photoreceptor. This is a method of developing an electrostatic latent image formed on the surface of a layer.

In addition, as the photosensitive layer constituting the photoreceptor, selenium photosensitive layer, zinc oxide photosensitive layer, cadmium sulfide photosensitive layer, organic photosensitive layer, amorphous silicon photosensitive layer, etc. are conventionally known. The layer is a photosensitive layer that is low in manufacturing cost and has excellent sensitivity, durability, heat resistance, and non-toxicity.

On the other hand, conventionally known resins used in toner include styrene-acrylic resins, polyester resins, and epoxy resins, which have excellent fixing properties such as hot offset resistance and toner release from the fixing cleaning roller. Polyester resin is suitable because of its properties.

Conventionally, as polyester resins used in toners, (1) polyester resins obtained by reacting monomer compositions consisting of bisphenol A propylene oxide, terephthalic acid, and trimellitic acid (Japanese Patent Laid-Open No. 57-37
(2) Bisphenol A propylene oxide, terephthalic acid, succinic acid substituted with an alkyl group having 12 carbon atoms,
Polyester resins obtained by reacting monomer compositions made of trimellitic acid (see Japanese Patent Application Laid-Open No. 59-9669) are known.

As a positively chargeable developer constructed using the above polyester resin, conventionally, (1) a technique in which a toner containing the above polyester resin is incorporated with a positively chargeable charge control agent, (2) the above polyester resin A technique of externally adding and mixing inorganic fine particles whose surface has been treated with polysiloxane having an ammonium salt as a functional group to a toner containing a fluorine-containing toner, and further mixing with a coating carrier coated with a fluororesin (Japanese Patent Application Laid-Open No. 1993-1912) 114858
(Refer to Japanese Patent Application Publication No. 1999-11-1), (1) Technology for lowering the acid value of the polyester resin and imparting positive chargeability to the polyester resin itself by using a polyhydric alcohol as a crosslinking component in the production of the polyester resin (Japanese Unexamined Patent Application Publication No. 1983-1999). 105561) is known.

[Problem to be solved by the invention]

However, in the technique (2) above, it is difficult to uniformly and finely disperse and contain a positively chargeable charge control agent in the polyester resin, so the charge control agent easily separates from the surface of the toner particles ( Therefore, as the development process is repeated, the charge control agent in the toner adheres to and contaminates the surfaces of carrier particles, organic photosensitive layers, developer transport carriers, etc., resulting in early deterioration of image quality.

Furthermore, the above techniques (1) and (2) have the following problems.

(a) The polyester resin contained in the toner is hard because its monomer composition contains bisphenol diol, which is a hard component, and therefore has an organic photosensitive layer, which is preferable as a photosensitive layer. When development is performed using a magnetic brush development method, which is preferable as a development method, using a latent image carrier, the abrasion force of the magnetic brush against the surface of the organic photosensitive layer becomes excessive, and as a result, scratches occur on the surface of the organic photosensitive layer relatively early. However, there is a problem in that white streak-like missing images occur in the image due to the scratches, and toner particles are embedded in the scratches, resulting in black streak-like stains due to poor cleaning.

(b) During development, the preceding toner image adhering to the electrostatic latent image is excessively rubbed by the succeeding magnetic brush, resulting in running streaks and white streaks in the toner image along the rubbing direction. There's a problem.

The present invention has been made based on the above circumstances, and its object is to provide an image forming method including a step of developing an electrostatic latent image on an organic photosensitive layer with a positively charging developer.
The toner can be positively charged in an appropriate range without using a charge control agent, and the image quality is improved without white stripes missing, black streaks, running streaks, or white streaks. An object of the present invention is to provide an image forming method that can stably form good images many times.

[Means to solve the problem]

In order to achieve the above object, in the image forming method of the present invention, a toner containing a polyester resin, inorganic fine particles whose surface has been treated with polysiloxane having an ammonium salt as a functional group, and a surface of a magnetic particle are used. In an image forming method that includes a step of developing a negative electrostatic latent image on an organic photoreceptor with a positively charging developer comprising a coating carrier coated with a fluororesin, the polyester resin may contain the following components A configuration using a polyester resin obtained by subjecting a monomer composition containing (1) to a polycondensation reaction is adopted.

Component (1); Aliphatic diol component ■; Aromatic dicarboxylic acid component (3); Trivalent or higher polyol In other words, the present invention uses trivalent or higher polyol (tf, minute )
By using this method, the toner itself is positively charged, and the surfaces of the inorganic fine particles and magnetic particles, which are surface-treated with polysiloxane having an ammonium salt as a functional group and used together with the toner, are coated with fluororesin. By interacting with the coating carrier, it is possible to stably impart a positive triboelectric charge in a suitable range to the toner, thereby reducing the carrier particles, organic photosensitive layer, and developer transport that occur when the toner contains a charge control agent. This solves the problem of contamination of carriers, etc., and in the production of the polyester resin, an aliphatic diol (component ■) is used instead of the conventionally used bisphenol diol as the diol component, and an aromatic By using a dicarboxylic acid (component ■) and a trivalent or higher polyol (component ■) together, the flexibility of the branched chains of the polyester resin obtained by the polycondensation reaction of these can be improved, and the flexibility of the branched chains of the polyester resin can be improved. By incorporating it into the toner, the impact energy of the magnetic brush that scratches the surface of the organic photosensitive layer is alleviated by the motion of the branched chains of the polyester resin, and the scratching force of the magnetic brush is suppressed to a small level. As a result, the examples described below As can be understood from the explanation, there are white streak-like missing images due to scratches on the organic photosensitive layer, black streak-like stains due to poor cleaning, running streaks due to the magnetic brush, and white streaks due to the magnetic brush. This makes it possible to stably form images of good quality many times without creating any sweeping marks.

The aliphatic diol of component (1) is preferably an aliphatic diol having 2 to 10 carbon atoms. Due to the presence of the aliphatic diol having such a carbon number, the resulting polyester resin exhibits the effect of effectively reducing the abrasion force against the organic photosensitive layer.

Note that in the case of an aliphatic diol having less than 2 carbon atoms, the flexibility of the molecular chain may be insufficient. On the other hand, aliphatic diols having more than 10 carbon atoms tend to film on the organic photosensitive layer during cleaning, and when this filming becomes noticeable, the potential of the filming portion increases and the image Black stains may appear on the white background.

Specific examples of the aliphatic diol of component (■) include (
1) Examples of aliphatic diols with branched chains include 1.2-propanediol, 1.2-butanediol, 1.3-
Butanediol, 2,3-butanediol, neopentyl glycol, 1,2-hexanediol, 2.5-hexanediol, 2-methyl-2,4-pentanediono to 3-methyl-1,5-bentanediol , 2-ethyl-1°3-hexanediol, etc.
(2) Examples of aliphatic diols without branched chains include ethylene glycol, 1.3-propanediol, 1.4-
Butanediol, diethylene glycol, 2-butene-
1,4-Dionobe 1,5-bentanediol, 1.
Examples include 6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol-)pepentaethylene glycol, and the like.

Here, the branched chain refers to two O
Refers to the other carbon chains when the main chain is a straight chain connected by carbons between H groups.

the condition of reducing the abrasion force against the organic photosensitive layer;
From the viewpoint of fully satisfying both the conditions of effectively preventing filming on the organic photosensitive layer, it is preferable that the proportion of the branched aliphatic diol is 50 mol % or more based on the total aliphatic diol.

From the above viewpoint, neopentyl glycol is particularly preferred as the branched aliphatic diol.

In addition, other diols may be used together with the above aliphatic diols. Such other diols include:
Examples include other diol monomers such as etherified bisphenols such as 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A, water-added bisphenol A, polyoxyethylenated hisphenol A, and polyoxypropylenated bisphenol A. can.

The blending ratio of such other diols is preferably 30 mol% or less of the total diols. When the blending ratio of the other diol is excessive, it may be difficult to sufficiently reduce the abrasion force against the organic photosensitive layer.

Examples of the aromatic dicarboxylic acid of component (2) include phthalic acid, isophthalic acid, terephthalic acid, and anhydrides or esters of these acids.

Note that other dicarboxylic acids may be used in combination with the above aromatic dicarboxylic acids. Such other dicarboxylic acids include, for example, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, curtaconic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, cepatic acid, malonic acid, or anhydrides of these acids. or lower alkyl ester, dimer of lyluic acid, and other 2
Mention may be made of functional organic acid monomers. The blending ratio of such other dicarboxylic acids is 3% of the total dicarboxylic acids.
It is preferably 0 mol% or less. If the blending ratio of the other dicarboxylic acid is too large, the glass transition point Tg of the resulting polyester resin tends to decrease, and the organic photosensitive layer is likely to be filmed by toner during cleaning, resulting in black stains on the white background of the image. may occur.

Examples of component (3) trivalent or higher polyols include sorbitol, glycerin, 1. 2. 3. 6-hexanetetrol, 1,4-sorbitan, pentaerythritol, diventaerythritonohetriventaerythritol, sucrose, 1,2.4-butanetriol, 1,2.5
-Pentanetriol, glyceronope 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-1-lihydroquinemethylbenzene, etc. can.

Among these polyols having a valence of 3 or more, trimethylolpropane is particularly preferred since it provides suitable positive chargeability.

The blending ratio of the polyol having a valence of 3 or more is preferably 1 to 30 mol% of the total polyol component. By selecting such a range, more preferable positive chargeability can be obtained.

The polyester resin used in the present invention preferably has an acid value (AV) in the range of 0.1 to 20, particularly preferably in the range of 0.1 to 5, in order to obtain more preferable positive chargeability. It is something that is in .

Here, the acid value (AV) refers to the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of sample.

In addition, the polyester resin used in the present invention has a softening point Tsp of 90 to 170° C. from the viewpoint of effectively preventing toner filming on the organic photosensitive layer and effectively reducing the abrasion force on the organic photosensitive layer. The temperature range is preferably from 100 to 160°C, particularly preferably from 100 to 160°C. When this softening point Tsp is too small, toner filming tends to occur on the organic photosensitive layer.
Black stains may appear on the white background of the image. on the other hand,
When the softening point Tsp is too high, it may be difficult to sufficiently reduce the abrasion force against the organic photosensitive layer.

Here, the "softening point TSI) J" is determined by using the Koka Type Flow Tester rCFT-500 model (manufactured by Takasu Seisakusho).
The measurement conditions were: load 20 kg/cm', nozzle diameter 1
mm, nozzle length 1 mm, preheating at 80°C for 10 minutes, heating rate 6°C/min, sample volume 1cm' (weight expressed as intrinsic specific gravity x 1cm'), when measuring and recording, the flow tester plan When the height of the S-curve in the jar drop temperature curve (softening flow curve) is h, h
/2.

Furthermore, the polyester resin used in the present invention effectively prevents filming on the organic photosensitive layer, and
From the viewpoint of effectively reducing scratches on the organic photosensitive layer, those having a glass transition point Tg in the range of 50 to 70°C are preferred. When the glass transition point TK is too small, filming tends to occur on the organic photosensitive layer, and black stains may occur on the white background of the image. On the other hand, when the glass transition point Tg is too high, it may be difficult to sufficiently reduce scratches on the organic photosensitive layer.

Here, "glass transition point Tg J" refers to a value measured by the following operation using a differential scanning calorimeter "low temperature DSC" (manufactured by Rigaku Denki Co., Ltd.).

(1) Place 30 mg of a powdered sample in an aluminum pan and raise the temperature from 20°C to 100°C at a heating rate of 10°C/min.

(2) Leave at 100°C for 3 minutes, then cool to 20°C by air cooling.

(3) After that, measurement was performed at a heating rate of 10°C/min, and the extension line of the baseline below the glass transition point of the DSC thermogram in the glass transition region and the maximum between the rising part of the peak and the top of the peak were measured. The temperature at the point of intersection with the tangent line indicating the slope is defined as the glass transition point.

The toner used in the present invention contains the above-mentioned polyester resin as an essential component, but if necessary, a colorant,
Other toner components such as a fixability improver may also be contained.

Examples of colorants include carbon black, nigrone dye, aniline blue, calco oil blue, chrome yellow, ultramarine flu Dupont oil red,
Quinoline yellow, methylene blue chloride, fuclocyanine blue malachite green offsalate, lamp black, rose benganope, mixtures thereof, and others can be used.

As the fixing property improver, for example, low molecular weight polyolefin such as low molecular weight polyethylene and polypropylene can be used.

The toner used in the present invention is produced by the usual method of mixing the above polyester resin and other additives used as necessary, melting and kneading the mixture, cooling it, pulverizing it, and then classifying it. be able to.

The inorganic fine particles used in the present invention are surface-treated with polysiloxane having an ammonium salt as a functional group.

Inorganic fine particles that have been surface-treated in this way have a smaller abrasion force against the organic photosensitive layer than normal inorganic fine particles because their surfaces are covered with polysiloxane, and they also have ammonium salt as a functional group. These functional groups and hydrophilic groups such as hydroxyl groups present on the surface of the inorganic fine particles are strongly bonded, and the inorganic fine particles have excellent moisture resistance and durability, and have stable positive charging properties that are not affected by environmental conditions. becomes.

As the polysiloxane having an ammonium salt as a functional group, dimethylpolysiloxane having an ammonium salt as a functional group is preferable because excellent positive chargeability can be obtained. Dimethylpolysiloxane having such an ammonium salt as a functional group is generally a dimethylsiloxane containing a structural unit represented by the following formula (A), and specifically represented by the structural formula of the following formula (B).

Formula (A) R 5iO- Formula (B) 2 R2-NG -R5. R3.X8 R1 represents a bonding group (e.g., alkylene group, arylene group, aralkylene group, -NH--NHCO-1
or any combination of these groups, etc.), or a simple bond; R, R, and R1 each represent a hydrogen atom, an alkyl group, or an aryl group, and X represents a halogen atom. Each layer represented by R, -R, includes a layer having a substituent. ) (Here, R6 and R7 each represent a hydrogen atom, a hydroxy group, an alkyl group, an aryl group, or an alkoxy group, and these groups include those having a substituent. R, -R9, and X are R+ − in the above formula (A)
Same as Rs and X. m and n each represent an integer of 1 or more. ) include those shown by the following structural formula, but are not limited to these.

(1) CH.

-(-CH#r-N・-CH,・C1eCH3 (2) CH.

Electric-CH2+T-NG-CH,・(10CH.

(3) Hs -fCH7+-T-N@→CH, h-rCH, ・αeC
H.

(4) CH.

→CH2h-N・-→CH2+TTCH3・JeHs (5) (8) -CaH4-N・H2' (JeCH3 (9) C2H4N”H(CH3)2・cIl.

(10) CH.

C3H6NHCaH4NG-CH5-Ci)e CH3 (11) -C,H, -NH-Co-N'H, -CI
7e(12) j20 C=H6N'H2C2H2C00C2H5(13)
C, H5 -C+Ha-NΦ H-CJe CH.

(6) C3H1ING (CH3)!・CJ"(7> -C,H, -N' H3-Cffe C2H, -0H C= Ha N@H-Cj2e C,H, -〇H As a method for obtaining polysiloxane having ammonium salt as a functional group, , a method in which an organohalogenated silane having an ammonium salt as a functional group and an organohalogenated silane that does not particularly have an ammonium base are copolymerized in the polymerization step, and a method obtained by polymerization using an organohalogenated silane. It can be obtained by a method of modifying a part of polysiloxane with an organic group having ammonium salt as a functional group.Here, organoalkoxysilane may be used instead of organohalogenated silane. The compound can also be obtained as a commercial product.

Examples of inorganic fine particles before surface treatment include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, chromium oxide, cerium oxide, antimony trioxide, zirconium oxide, and carbide. Fine particles such as silicon can be used.

Among these, silica fine particles are particularly preferably used since they can also improve the fluidity of the developer. The silica fine particles are fine particles having a 5i-0-5i bond, and may be manufactured by either a dry method or a wet method, but those manufactured by a dry method are preferable, and in particular, silicon halogen compounds. Preferably, the silica particles are produced by vapor phase oxidation of silica particles.

In addition, as silica fine particles, silicon dioxide (silica)
In addition, fine particles made of silicates such as aluminum silicate, sodium silicate, calcium silicate, potassium silicate, zinc silicate, and magnesium silicate may also be used, but those containing 85% by weight or more of SiO2. is preferred.

As a method for treating the surface of inorganic fine particles with polysiloxane having an ammonium salt as a functional group, a known technique can be used. Specifically, for example, a polysiloxane having an ammonium salt as a functional group is dissolved in a solvent. After dispersing inorganic fine particles in a solution, the solvent is removed by filtration or spray drying, and then cured by heating, or by using a fluidizing bed device, polysiloxane having an ammonium salt as a functional group is dissolved in a solvent. A method can be used, such as spraying a solution dissolved in inorganic particles onto inorganic fine particles and then heating and drying to remove the solvent and harden the film.

Primary particles of inorganic fine particles surface-treated in this way (
The average particle size of particles (separated into individual unit particles) is
3IT is preferably about 1μ to 2μ, particularly about 5mμ to 500mμ. In addition, the specific surface area according to the BET method is 20 to 500 m
About 2/g is good. If the average particle diameter is too small or the specific surface area is too large, the inorganic particles may easily slip through during cleaning using, for example, a blade-type cleaning device, resulting in poor cleaning.

On the other hand, when the average particle diameter is too large or the specific surface area is too small, the abrasion force against the organic photosensitive layer may not be sufficiently reduced.

Such surface-treated inorganic fine particles are used by being added to and mixed with the toner from the outside so that they are attached to the surface of the toner particles.

The blending ratio of such surface-treated inorganic fine particles is preferably 0.1 to 5% by weight, particularly 0.1 to 2% by weight of the toner. When this blending ratio is too small, the fluidity of the developer may decrease, resulting in poor triboelectric charging properties of the toner, making it difficult to impart an appropriate amount of positive charge to the toner. Fog may occur. On the other hand, when this content ratio is excessive, some of the inorganic fine particles may exist in a free state from the toner particles, and as a result, the abrasion force against the organic photosensitive layer may not be sufficiently reduced.

The carrier used in the present invention is a coated carrier coated with a fluororesin. A coated carrier coated with a fluororesin is suitable for toner because the abrasion force against the organic photosensitive layer can be sufficiently reduced compared to a carrier that is not coated, and it is also easier to obtain a negatively charged coated carrier. It is possible to impart a positive chargeability within a range.

However, when the surface of the magnetic particles is coated only with a fluororesin, the coating layer tends to peel off due to the weak adhesion between the fluororesin and the magnetic particles, and the magnetic particles are removed in the peeled off area. The surface is exposed, and the surface of the organic photosensitive layer may be scratched by this exposed portion, resulting in scratches.

Therefore, it is preferable to form a two-layer coating layer by forming an inner layer using a resin that has good adhesion to magnetic particles, and forming an outer layer using a fluorine-based resin on the surface of this inner layer. .

As the magnetic particles that are the core material of the coating carrier, known magnetic particles can be used, specifically,
Examples include particles such as ferrite and magnetite. The average particle size (weight) of these magnetic particles is 10 to 50
A range of 0 μ is preferable.

The inner layer resin constituting the inner layer of the coating layer is preferably one that has good adhesion to the magnetic particles from the viewpoint of increasing film strength, and one that has good adhesion to the fluororesin that makes up the outer layer. preferable.

As the inner layer resin, styrene resins such as polystyrene and styrene/alkyl (meth)acrylate copolymers are preferred. Specifically, alkylstyrenes such as styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene, fluorostyrene, and chlorostyrene. , halogenated styrenes such as bromostyrene, dipromostyrene, and iodostyrene; homopolymers of styrenic monomers such as nitrostyrene, acetylstyrene, and methoxystyrene; copolymers of these styrene monomers; Examples include copolymers with alkyl (meth)acrylates.

Among these styrene resins, styrene homopolymers and copolymers of styrene and alkyl (meth)acrylates are preferred, and copolymers of styrene and alkyl (meth)acrylates are particularly preferred. Such styrene resin has good adhesion with the magnetic particles and the fluorine resin constituting the outer layer, so the mechanical strength of the coating layer is high and it is difficult to peel off.
It is possible to effectively prevent the phenomenon that the surface of the magnetic particles is exposed and scratches the surface of the organic photosensitive layer.

A specific example of such a copolymer of styrene and alkyl (meth)acrylate is preferably a copolymer of styrene and methyl methacrylate (MMA). In such a copolymer, the molar ratio of styrene repeating units to methyl methacrylate repeating units is 50:50 to 95:
The ratio is preferably 5, more preferably 55:45 to 90:10, and particularly preferably 60:40 to 90:10. According to the copolymer in this range, the mechanical strength of the inner layer is significantly increased, and it is possible to sufficiently prevent the organic photosensitive layer from being scratched by the exposed surface of the magnetic particles caused by peeling off of the inner layer. can.

Moreover, the weight average molecular weight Mw of such a copolymer is 50.
The range of 000 to 300.000 is good, and the ratio of weight average molecular weight IMw to number average molecular weight Mn Mw/M
The value of n is preferably in the range of 1.0 to 5.0, particularly 1.5 to 5.0.
A range of 2.5 is preferred.

Further, such a copolymer may contain other repeating units other than styrene and methyl methacrylate as needed.

A fluororesin is used as the outer layer resin constituting the outer layer of the coating layer. Such a fluororesin contains 5 fluorinated alkyl (meth)acrylate repeating units.
Polymers containing 0 mol % or more, especially 55 mol % or more are preferred. Since such a polymer exhibits excellent negative charging properties, it is possible to impart a suitable positive triboelectric charge to the toner, and in particular, the rise in the amount of charge at the beginning of use is good, and the initial The amount of charge can be stabilized.

In addition, in the entire outer layer, the above fluorinated alkyl (
The content of the meth)acrylate polymer is preferably 70% by weight or more, particularly preferably 75% by weight or more.

Within this range, it is possible to further improve triboelectric charging properties and mechanical strength.

Examples of the fluorinated alkyl (meth)acrylate repeating unit in such a fluorinated alkyl (meth)acrylate polymer include a repeating unit represented by the following formula (C).

(C) +CH2-CR') 0=C-R' (However, R1 represents a hydrogen atom or a methyl group,
R2 is a residue obtained by removing a hydrogen atom from a hydroxyl group of an alcohol compound containing an alkyl group in which at least - hydrogen atom is substituted with a fluorine atom. ) Among the repeating units represented by the above formula (C), preferred specific examples from the viewpoint of triboelectric charging properties and mechanical strength include those represented by the following formulas (D) and (E). These alone are
Or they can be used in combination.

(D) +CH2-CR'+ 0=C-O child CH,)ゎC11F211+(E)
(CH2-CR'+ 0=C-OiCR2), (CF, ), H (however, R
1 represents a hydrogen atom or a methyl group, n and p each represent an integer of 1 to 8, and m and q each represent an integer of 1 to 19. ) Among these, particularly preferable fluorinated alkyl (meth)acrylate repeating units are those of the following formulas (F) to (H
) can be mentioned.

(F) +CH2-CR’+ 0=COCH2CF.

(G) -(=CH, -CR'-)-0=COC
H2 (CF, )2 H (H) -+CH, -CR'+ ○=C0CH2CF, CF3 (However, R1 is a hydrogen atom or a methyl group.

) The fluorinated alkyl (meth)acrylate polymer may contain other repeating units in addition to the above repeating units. As such other repeating units, styrene, methylstyrene, metinope acrylate, and methyl methacrylate are preferred.

Other polymers that can be used as the resin constituting the outer layer together with the fluorinated alkyl (meth)acrylate polymer include acrylic polymers such as polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate, and polyethyl acrylate. Examples include resins. Among these, polymethyl methacrylate is particularly preferred.

In the coating layer, the thickness of the inner layer is 0.1 to 2.0
The thickness of the outer layer is preferably in the range of 0.1 to 2.0μ, and the total thickness of the coating layer is 0.2μ.
A range of ~4.0 μ is preferable.

The coated carrier used in the present invention can be manufactured by conventional coating means.

The organic photoreceptor used in the present invention is constructed by laminating an organic photoreceptor layer containing an organic photoconductive substance dispersed in a binder resin, for example, on a conductive support made of aluminum, stainless steel, etc. It is what was done.

For the organic photosensitive layer, from the viewpoint of particularly increasing durability, carrier-generating substances that absorb image exposure light and generate charge carriers, such as anthanthrone compounds, perylene derivatives, bisazo compounds, and phthalocyanine compounds, are used. , such as styrene-methyl methacrylate copolymer,
A carrier generation layer configured by dispersing and containing a carrier in a binder resin such as a polycarbonate resin or a silicone resin;
For example, a carrier transport substance that transports carriers generated in the carrier generation layer, such as oxadiazole derivatives, triarylamine derivatives, polyarylalkane derivatives, hydrazone derivatives, stilbene derivatives, and styryltriarylamine derivatives, is mixed in the same binder resin as above. It is preferable to use a functionally separated type photosensitive layer formed by combining a carrier transport layer configured by dispersing and containing a carrier transport layer and a carrier transport layer.

FIG. 1 shows an example of an image forming apparatus that can be used to implement the image forming method of the present invention. Reference numeral 10 denotes an organic photoreceptor, and this organic photoreceptor IO has a rotating drum shape. Around the organic photoreceptor 10, in order from the upstream side to the downstream side in the rotational direction, a corona charger 20, an exposure optical system 30, a contact type magnetic brush developer 40, an electrostatic transfer device 50, a separator 60, A blade type cleaning device 70 is arranged. 80 is a heat roller fixing device.

In this image forming apparatus, the surface of the organic photoreceptor 10 is charged to a -like potential by the corona charger 20, and then imagewise exposed by the exposure optical system 30, so that the surface of the organic photoreceptor 10 is charged with a static image corresponding to the original. A latent image is formed. Then, the electrostatic latent image is developed using a magnetic brush developing method using a developer containing a toner containing the specific polyester, which is housed in the contact type magnetic brush developing device 40, thereby forming a document. A toner image is formed. This toner image is electrostatically transferred onto a transfer material P by an electrostatic transfer device 50, and heated and fixed by a heat roller fixing device 80 to form a fixed image. On the other hand, the organic photoreceptor 1 that has passed through the electrostatic transfer device 50
0 has its surface rubbed by a blade-type cleaning device 70 to scrape off residual toner to return it to its original clean surface, which is then subjected to a charging process by a corona charger 20 again to form the next image. Served.

〔Example〕

Examples of the present invention will be described below along with comparative examples, but the present invention is not limited to these embodiments. In addition,
In the following, "parts" represent "parts by weight."

Production of polyester> The dicarboxylic acids and diols listed in Table 1 below were placed in a four-hole round bottom flask with a capacity of Place the flask in a mantle heater, introduce nitrogen gas through the nitrogen gas introduction tube, and raise the temperature while maintaining an inert atmosphere inside the flask.
Next, 0.05 g of dibutyltin oxide was added and reacted while keeping the temperature at 200°C.
Each polyester was obtained by adding a polyol having a value higher than the value and further reacting.

The acid value (AV), softening point Tsp, and glass transition point Tg of each polyester are as shown in Table 2 below.

<Manufacture of toner> Toner 1 (for the present invention) 100 parts of polyester 1 shown in Table 1, 10 parts of carbon black "Mogul LJ" (manufactured by Cabot Corporation), and 3 parts of polypropylene "Viscol 550PJ (manufactured by Sanyo Chemical Industries, Ltd.) After mixing with a V-type blender,
Thoroughly melt-kneaded at 100 to 130°C with two rolls, then cooled, and then coarsely ground with a hammer mill,
Furthermore, it is finely pulverized by a jet mill, then classified,
A toner 1 having an average particle size of 11.0 μm was produced.

Toner 2 (for the present invention) Toner 1 was manufactured in the same manner except that polyester 1 was changed to polyester 2, and the average particle size was 1 (3).
; Toner 2 of 5 μm was produced.

Toner 3 (for the present invention) Toner 1 was produced in the same manner except that polyester 1 was changed to polyester 3, and the average particle size was 11.5.
Toner 3 of μ was produced.

Toner a (for comparison) In the production of Toner 1, Polyester 1 was changed to Comparative Polyester 1, and the charge control agent "Bontron P-51" was added.
A comparative toner a having an average particle size of 11.0 μm was produced in the same manner except that 1 part of J (manufactured by Orient Chemical Co., Ltd.) was added.

Kunu 8a@Manufacture of particles> Inorganic fine particles 1 (for the present invention) A treatment liquid was prepared by dissolving a polysiloxane having an ammonium base represented by the following formula (2) as a constituent unit in xylene.

Formula ■ (CHz)s H2O-NΦ-CH3-cle Australia CH, (x is an integer) Next, put silica fine particles "Aerosil 200J (manufactured by Nippon Aerosil Co., Ltd.) into a mixer, and add the above polyester to the silica fine particles. After spraying the siloxane at a ratio of 5% by weight, these were placed in a flask, and the solvent xylene was removed at a temperature of 200°C for 5 hours with stirring to obtain surface-treated inorganic fine particles l. The inorganic fine particles 1 have an average primary particle diameter of 12 mμ, B
The specific surface area by ET method was 1151 Tl"/g■
Inorganic fine particles 2 (for the present invention) A treatment liquid was prepared by dissolving a polysiloxane having an ammonium base represented by the following formula (2) as a constituent unit in xylene.

Expression ■ -CH5'(Je CH.

(y is an integer) Next, silica fine particles "Aerosil 300J (manufactured by Nippon Aerosil Co., Ltd.) were placed in a mixer, and the above polysiloxane was sprayed at a ratio of 17% by weight to the silica fine particles. Surface-treated inorganic fine particles 2 were obtained in the same manner as in the production of inorganic fine particles 1. The inorganic fine particles 2 had an average primary particle diameter of 7 mμ and a specific surface area of 126 m / g by the BET method. .

Inorganic fine particles a (for comparison) Negatively charged silica fine particles "Aerosil R-972J (manufactured by Nippon Aerosil Co., Ltd.) are used as inorganic fine particles a.

Manufacture of carrier> Carrier 1 (for the present invention) Styrene/methyl methacrylate copolymer resin (copolymerization molar ratio = 6:4. Mw = 120.0OO)
A coating solution for the inner layer was prepared by dissolving 15 g in methyl ethyl ketone 300%.

Using this inner layer coating liquid, an inner layer with an average thickness of 1.0 μm was formed on the surface of spherical ferrite particles [F-150J (manufactured by Nippon Tetsuko Kogyo Co., Ltd.) using a spira coater (manufactured by Kaida Seiko Co., Ltd.). I got a career.

Then acrylic acid-1,1,3-trihydroperfluoro-n-propyl/acrylic acid-i.

A coating liquid for the outer layer was prepared by dissolving 12 g of 1-dihydroperfluoro-n-propyl copolymer resin in 500 mj' of acetone.

Using this outer layer coating liquid, an outer layer is formed on the surface of the inner layer of the secondary carrier using a Subira coater (manufactured by Kaida Seiko Co., Ltd.), so that the outer layer has a resin coating layer with a total average thickness of about 2μ and an average particle size. A coated carrier of 80 μm was manufactured. This will be referred to as “Carrier I”.

Carrier 2 (for the present invention) Styrene/methyl methacrylate copolymer resin (copolymerization molar ratio = 6: 4. Mw = 134,000
, Mw/Mn = 1.9) 2 (l g) in a mixed solvent of toluene and Z9/-, +1/ (volume ratio = 9:1
) 400m1! A coating liquid for the inner layer was prepared by dissolving it in

Using this inner layer coating liquid, an inner layer with an average film thickness of 1.0 μm was formed on the surface of spherical ferrite particles F-150J (manufactured by Nippon Tetsuko Kogyo Co., Ltd.) using the Subira Coater “Okada Seiko Co., Ltd.”. I got a career.

Next, it consists of a repeating unit represented by the following formula (I) and has an intrinsic viscosity η of 0 in methyl ethyl ketone at a temperature of 35°C.
．． A coating liquid for the outer layer was prepared by dissolving 40 g of a 49 J/g fluorinated alkyl methacrylate polymer in 800 mf of toluene.

(1) CH.

+CH, -C) 0=COC82CF3 Using this outer layer coating liquid, an outer layer was formed on the surface of the inner layer of the -order carrier using a Subira coater (manufactured by Kaida Seiko Co., Ltd.), thereby forming a resin coating with a total average film thickness of about 2μ. A coated carrier having a layer and an average particle size of 80 μm was produced.This will be referred to as “Carrier 2”.

Carrier a (for comparison) Spherical ferrite particles 'F-150J (manufactured by Nippon Iron Powder Industries Co., Ltd.) are used as carrier a.

Manufacture of developer> Using the combination of toner, inorganic fine particles, and carrier shown in Table 3 below, first add the inorganic fine particles to the toner from the outside and mix them with a Henschel mixer to coat the surface of the toner particles. Each developer was manufactured by adhering inorganic fine particles and further mixing a carrier thereto.

Photoreceptor> Organic photoreceptor 1 (for the present invention) An organic photoreceptor layer with a negatively charged two-layer structure composed of an anthurone pigment as a carrier-generating substance and a carbazole derivative as a carrier-transporting substance is placed on a rotating drum. Organic photoreceptor 1 was manufactured by laminating the organic photoreceptor 1 on a conductive support made of aluminum.

Organic photoreceptor 2 (for the present invention) Isofukyo body 2 was manufactured in the same manner as organic photoreceptor 1 except that a bisazo pigment was used as a carrier generating substance and a hydrazone derivative was used as a carrier transporting substance. .

Organic photoreceptor 3 (for the present invention) Organic photoreceptor 3 was produced in the same manner as organic photoreceptor 1, except that a bisazo pigment was used as a carrier-generating substance and a styryl triarylamine derivative was used as a carrier-transporting substance. Manufactured.

[Examples 1 to 3 and Comparative Example 1] In each of the Examples and Comparative Examples, a low temperature of 10°C and a relative humidity of 20% was applied using the following image forming apparatus using a developer selected from the above-mentioned developers. Copied images were continuously formed 100,000 times under low humidity environmental conditions, and each of the following items was evaluated. The evaluation results are shown in Table 4 below.

<Image forming apparatus> Electrophotographic copying machine rU-Bix 1550MRJ (
This is a modified Konica-based machine, and the main components are as follows.

Photoconductor As shown in Table 4 below, a photoconductor selected from the above-mentioned rA photoconductors was mounted.

Equipped with a contact type magnetic brush developer for two-component developer.

A heat roller with a diameter of 3Qmm whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by Denipon Corporation) and a backup roller whose surface layer is made of silicone rubber rKE-1300RTVJ (manufactured by Shin-Etsu Chemical Co., Ltd.). Equipped with a fixing device.

Cleaning device Equipped with a cleaning device equipped with a cleaning blade made of urethane rubber.

<Evaluation Items> (1) Frictional charging of toner The initial charge amount and final charge amount of the toner were measured and evaluated using a known blow-off method.

(2) Blank image of white streaks The copied image was visually observed and evaluated. Note that "white streak-like image missing" refers to a phenomenon in which a part of the image is missing in a streak-like manner.

(3) Black streak-like stains The copied image was visually observed and evaluated. Note that "black streak-like dirt" refers to a phenomenon in which streak-like black dirt is generated due to poor cleaning.

(4) The flow streak copy image was visually observed and evaluated. Note that "flow streaks" refers to a phenomenon in which an image is distorted and a tail appears at the rear end of the image.

(5) The white streak-like swept-grain copy image was visually observed and evaluated. Note that "white streaks" refers to a phenomenon in which a linear difference in shading appears in an image.

In addition, in Table 4 below, "○" means good, "△" means slightly poor but at a practical level,
"X" indicates that the product is defective and has a practical problem.

As can be understood from the above results, according to the examples of the present invention, the initial charge amount of the toner is good even though the toner does not contain a charge control agent, and this good positive charge is obtained. The charging properties remain stable even after 100,000 copies, and images with good image quality are produced without white streaks, black streaks, run streaks, or white streaks. Stable formation was possible up to 100,000 times.

On the other hand, according to Comparative Example 1, the polyester resin contained in the toner is a polyester obtained from a monomer composition that does not contain an aliphatic diol but contains an aromatic diol, and In addition to being cross-linked polyester for comparison, the inorganic fine particles are negatively chargeable inorganic fine particles for comparison, and the carrier is an uncoated carrier for comparison, so the chargeability of the toner is negatively chargeable. As a result, the initial image became a reversed image, making it impossible to put it to practical use.

According to Comparative Example 2, the polyester resin contained in the toner was polyester for comparison as in Comparative Example 1, and the carrier was an uncoated carrier for comparison, so the charging properties of the toner were extremely poor. As a result, significant fogging from the initial image to the background occurred, making it impossible to put it to practical use.

According to Comparative Example 3, since the polyester resin contained in the toner is a comparative polyester as in Comparative Example 1, white streak-like missing images, black streak-like stains, running streaks, and white streaks appear. All of the sweeps occurred early.

In addition, in Examples 1 to 3, after 100,000 copies,
When the surface of the organic photoreceptor was visually observed, no scratches were particularly observed.

Further, in Examples 1 to 3, when the copied images were visually observed to check for stains caused by the offset phenomenon, no stains were found. Further, no stains on the roller of the heat roller fixing device were observed.

〔Effect of the invention〕

As explained in detail above, according to the image forming method of the present invention, the polyester resin contained in the toner is obtained from a monomer composition that also contains a trivalent or higher polyol, so the toner itself is positively charged. The interaction between the inorganic fine particles whose surface has been treated with polysiloxane having an ammonium salt as a functional group and the coating carrier whose surface of magnetic particles is coated with a fluororesin makes it suitable for toner. A positive triboelectric charge within a range is stably applied.

Since the polyester resin contained in the toner is obtained from a monomer composition that also contains an aliphatic diol, the flexibility of the branched chains of the polyester resin is good, and as a result, the organic photosensitive layer is not easily affected by the developer. To suppress the abrasion force to a sufficiently small level and to stably form images of good image quality over a large number of times without white streak-like image omissions, black streak-like dirt, running streaks, or white streak-like sweeping marks. I can do it.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of an image forming apparatus that can be used to implement the present invention. lO...Latent image carrier 20...Corona charger 30...Exposure optical system 40...Contact type magnetic brush developer 50...Electrostatic transfer device 60...Separator 70.
・Blade type cleaning device

Claims (1)

[Claims] (1) A toner comprising a toner containing a polyester resin, inorganic fine particles whose surface is treated with polysiloxane having an ammonium salt as a functional group, and a coating carrier whose surface is a magnetic particle coated with a fluororesin. In an image forming method including a step of developing a negative electrostatic latent image on an organic photoreceptor with a chargeable developer, the following components (1) to (3) are used as the polyester resin.
) An image forming method characterized by using a polyester resin obtained by subjecting a monomer composition containing the following to a polycondensation reaction. Component (1); Aliphatic diol component (2); Aromatic dicarboxylic acid component (3); Trivalent or higher polyol