JP2860841B2 - Image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner image forming method using a two-component developer.

[0002]

2. Description of the Related Art In electrophotography and the like, an electrostatic latent image is generally formed on a latent image carrier by charging and exposure, and the electrostatic latent image is developed with toner. The image is transferred and fixed to a support such as the above to form a visible image.

Recently, (a) prevention of thermal deterioration of the photoreceptor, (b) shortening of the warm-up type, (c) maintaining the temperature of the heat roller during continuous copying for a long time, (d) curling of paper, and prevention of jamming Therefore, it is strongly demanded that the fixing process can be performed with the temperature of the heat roller lowered. Therefore, it is necessary that the toner can be well fixed at a low temperature.

In addition, the toner needs to have excellent blocking resistance, and the heat roller fixing system needs to have offset resistance.

In view of such demands, many studies have been made on low-temperature fixing toners.
No. 50-87032 and No. 59-3446 disclose a toner using a binder resin composed of a crystalline resin and an amorphous polymer as a technique for improving low-temperature fixability, but still a blocking phenomenon or An offset phenomenon and a filming phenomenon occur, and a satisfactory image cannot be obtained. In addition,
Nos. 56-154740 and 57-8549 disclose a technique for improving the offset resistance by using a binder resin composed of a crystalline resin and an amorphous polymer in a toner, but the fluidity of the toner has been reduced. Poor, causing unclear images and image deterioration.

Further, as a technique for improving the triboelectric charging property between the carrier and the toner in a two-component developer, it is known to include a charge control agent in the toner and coat the surface of the carrier with a fluorine-based resin (Japanese Patent Laid-Open No. Sho 62). -229158).

However, when used in combination with a conventional toner, none of the toners sufficiently satisfies both low-temperature fixability and offset resistance.

A triboelectric charge control layer further comprising a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer, wherein the carrier core material comprises a fluorinated alkyl (meth) acrylate polymer. (Japanese Patent Laid-Open No. 2-186360).

However, although a carrier is coated with a fluorinated alkyl (meth) acrylate polymer having a low surface energy to suppress toner spent, a developing device is required because it contains a large amount of a substance that melts at a low temperature. It is inevitable that the toner is spent on the carrier due to the stress received inside. Further, since the crystalline polyester in the binder resin is filmed on the developer carrier, the amount of the developer transported is reduced, and as a result, the image density is reduced. This causes a problem that the density difference at the rear end increases.

On the other hand, many studies have been made on carriers.

A metal magnetic carrier conventionally used as a carrier has (1) a large specific gravity and a large mixing and stirring torque during frictional charging with toner.

(2) Therefore, the mechanical pressure on the toner is large, the toner filming on the carrier surface is large, and the life of the developer is short.

There are problems such as the following.

In contrast to the above problems, Japanese Patent Application Laid-Open No. 58-23032 discloses ferrite-based oxides such as nickel oxide, zinc oxide and iron oxide having a lower specific gravity than metals such as iron (specific gravity: about 5%).
g / cc) to further select ferrite carrier particles and other conditions such as the spray drying method to introduce cavities into the particles, reduce the stirring torque when mixing the developer, and extend the life of the developer. Stretching techniques have been proposed.

However, if the porosity calculated from the theoretical density and the measured density exceeds 50%, the mechanical strength of the particles becomes weak, so that the particles are broken during mixing and stirring, and the life of the developer is reduced.
Therefore, the porosity of 4 to 40% is preferably good in terms of life.

However, the porosity of the ferrite carrier is 4
At 4040%, the mechanical stress in the developing device is reduced, but the mechanical strength of the carrier is weak and the carrier is destroyed, so that filming and fogging of the carrier residue occur.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-temperature fixing method which has a small amount of toner spent, a long developing stability, a small amount of filming of a toner to a developer conveying member mechanically, and a carrier is not destroyed. It is to provide a possible image forming method.

[0018]

According to the present invention, there is provided an electrostatic latent image developer comprising: a toner having a binder in which a crystalline polyester and an amorphous vinyl polymer are chemically bonded; and an apparent specific gravity of 2.5 to 4.0. A developer containing a carrier formed of a resin containing magnetic particles of g / cc, a surface roughness of 20 to 60
This is achieved by an image forming method, which is carried on a developer carrier having a 10-point average roughness Rz of μm, transported to a development area, and developing an electrostatic image formed on a latent image carrier. .

Hereinafter, the present invention will be described in detail.

The toner constituting the electrostatic image developer of the present invention contains, as a binder resin, a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer. In the case of melting, the low-temperature fixability due to the good wettability of the crystalline polyester component and the offset resistance due to the high viscoelasticity of the amorphous vinyl polymer can be obtained. Therefore, the low-temperature fixing property and the offset resistance are good, and the fixing can be performed in a wide temperature range. The crystalline polyester is not particularly limited, but is preferably a polyalkylene polyester in order to improve the low-temperature fixability and fluidity of the toner.

Specific examples of such polyalkylene polyesters include, for example, polyethylene sebacate, polyethylene adipate, polyethylene suberate, polyethylene succinate, polyethylene-p- (carbophenoxy) undecaate, polyhexamethylene oxalate, polyhexamethylene Sebacate, polyhexamethylene decanedioate, polyoctamethylene dodecandioate, polynonamethylene azelate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene oxalate, polydecamethylene sebacate,
Polydecamethylene succinate, polydecamethylene dodecandioate, polydecamethylene octadecanedioate, polytetramethylene sebacate, polytrimethylene dodecandioate, polytrimethylene octadecanedioate, polytrimethylene octadecanate, polytrimethylene oxalate, polyhexamethylene -Decamethylene-sebacate, polyoxydecamethylene-2-methyl-1,3-propane-dodecandioate, and the like.

The crystalline polyester has a melting point Tm.
Is preferably in the range of 50 to 120 ° C. When the melting point Tm of the crystalline polyester used is less than 50 ° C., the obtained toner has poor blocking resistance,
If the ratio exceeds the range, the melt fluidity of the toner at a low temperature may be reduced, and the fixability may be deteriorated. Here, the melting point Tm of the crystalline polyester means the melting point of the crystalline polyester in a state where it is not bonded to the amorphous vinyl polymer.

If the weight average molecular weight Mw of the crystalline polyester is in the range of 5 × 10 ^{3 to} 5 × 10 ⁴ , the offset resistance of the toner and the pulverization efficiency in the production of the toner are improved.

In order to obtain a toner having a low minimum fixing temperature and a high offset resistance at a high temperature, the crystalline polyester is used in an amount of 3 to 50% by weight in the block copolymer or the graft copolymer with the amorphous vinyl polymer. A range is preferred.

The vinyl polymer constituting the main part of the amorphous vinyl polymer used in the present invention is selected from styrene monomers, acrylate monomers and methacrylate monomers. Obtained using at least one of the following.

Examples of the styrene monomer include styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene,
Examples thereof include 2,3-dimethylstyrene, 2,4-dimethylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene.

Examples of the acrylate-based monomers include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic acid- 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl acrylate and the like can be mentioned.

Examples of the above-mentioned methacrylate monomer include methyl methacrylate, ethyl methacrylate, and the like.
Propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Is mentioned.

The amorphous vinyl polymer used in the present invention contains a monomer having a carboxyl group, a hydroxyl group, an amino group or an epoxy group, which is involved in a block or graft copolymer with the crystalline polyester. Should be fine.

Examples of monomers having a carboxyl group, a hydroxyl group, an amino group or an epoxy group include acrylic acid, β, β-dimethylacrylic acid, α-ethylacrylic acid, methacrylic acid, fumaric acid, itaconic acid, and maleic acid. Crotonic acid, hydroxyethyl methacrylate, monoacryloyloxyethyl phthalate, monoacryloyloxyethyl succinate, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, p-aminostyrene, glycidyl methacrylate and the like. . Such a monomer having a functional group is used in a monomer composition for obtaining an amorphous vinyl polymer in a range of 0.1 to 20 mol%.

The amorphous vinyl polymer used in the present invention is preferably one in which a polyvalent metal compound reacts with a carboxyl group of a vinyl polymer having a carboxyl group to form an ionic cross-linking bond.

As the metal element of the polyvalent metal compound,
Alkaline earth metals or zinc group elements are preferred, especially Mg,
Zn is preferred.

To ionically crosslink the vinyl polymer, for example, the above polyvalent metal compound is mixed with a solution containing a vinyl polymer having a carboxyl group obtained by polymerization by a solution polymer method, and the temperature is raised. The temperature in the reaction system is 150-180 ℃
It is preferred that the reaction be completed by maintaining the temperature at this temperature for at least 1 hour when the temperature reaches the level.

From the viewpoint of further improving low-temperature fixability and offset resistance, the amorphous vinyl polymer preferably has at least two or more maximum values in the molecular weight distribution. That is, it has a molecular weight distribution divided into at least two groups of a low molecular weight component and a high molecular weight component, and in a molecular weight distribution curve measured by gel permeation chromatography (GPC), at least one maximum value is 2 × 10 It is preferred to have at least two maxima such that they lie in the range ^{3 to} 2 × 10 ⁴ and at least one maxima lies in the range 1 × 10 ⁵ to 1 × 10 ⁶ .

The high molecular weight component makes the amorphous vinyl polymer tougher, and prevents the toner particles from being destroyed by friction with a carrier or mechanical external force such as stirring in a developing device, and the filming phenomenon is prevented. The generation of the caustic fine slag is controlled. The proportion of the high molecular weight component in the amorphous vinyl polymer is preferably 15% by weight or more.

The destruction of toner particles caused by friction with a carrier or mechanical external force such as stirring in a developing device is mainly caused by low-molecular-weight relatively brittle components in the toner particles. It is preferred that the molecular weight component be ionically cross-linked to make it tough and impart breakage resistance to the toner particles.

In the amorphous vinyl polymer, the values of the weight average molecular weight Mw and the number average molecular weight Mw / Mn are preferably 3.5 or more, particularly preferably 4 to 40. When the ratio Mw / Mn is too small, sufficient offset resistance and durability cannot be obtained.

The glass transition point Tg of the amorphous vinyl polymer is preferably from 50 to 100 ° C. from the viewpoints of low-temperature fixability, offset resistance, blocking resistance and durability. Here, the glass transition point Tg is a value measured based on differential scanning calorimetry (DSC).

Further, the softening point of the amorphous vinyl polymer is preferably from 100 to 150 ° C. This softening point is measured using a Koka type flow tester (Shimadzu Corporation).

In order to obtain a copolymer obtained by chemically bonding the above-mentioned crystalline polyester and the above-mentioned amorphous vinyl polymer, for example, a head-to-tail coupling reaction between terminal functional groups present in each polymer is carried out. Can be directly connected to one another in a fashion. Alternatively, the terminal functional group of each polymer can be linked with a bifunctional coupling agent, such as diisocyanate,
Examples thereof include dicarboxylic acid, glycol, phosgene, and dichlorodimethylsilane.

In the present invention, it is preferable that the above-mentioned copolymer is contained in at least 5% by weight of all toners.

The carrier used in the developer of the present invention is obtained by coating magnetic particles having an apparent specific gravity of 2.5 to 4.0 g / cc with a resin, and if the specific gravity is less than 2.5, the mechanical strength is insufficient and the carrier of the carrier is insufficient. Breakage, filming of generated carrier scum, fogging, etc. are caused, and if it exceeds 4.0, the stress applied to the toner increases, causing toner crushing and toner splatting, resulting in a loss of development homeostasis.

Here, the apparent specific gravity is a specific gravity including voids.

The magnetic material is a ferrite made of a sintered body of an oxide such as zinc, manganese, copper, magnesium, lithium, barium, etc. and an iron oxide. Body.

The resin used for coating the carrier includes fluorine-based resins such as vinylidene fluoride-tetrafluoroethylene copolymer, tetrafluoroethylene, 2,2,2-trifluoroethyl methacrylate and pentafluoropropyl methacrylate. ,
A styrene resin, an acrylic resin, a silicone resin, or the like is used alone or in combination.

For the surface coating of the ferrite body, a spray coating method of a resin solution, a dry coating method of hitting and adhering a resin powder by mechanical impact force and the like are used.

The average particle size of the carrier is preferably from 10 to 200 μm.

The particle size was measured using a Microtrac (type 7981).
-OX; manufactured by Reed & Northlap Co.).

The apparent specific gravity was measured with a multi-volume density meter 1305 (manufactured by Micromeritics Co.) of constant volume expansion method.

A non-magnetic, conductive metal, for example, a cylinder of 0.5 to 1.5 mm in thickness, such as aluminum or brass, is used for the developer carrier applied to the present invention. The surface is roughened to have a point average roughness Rz: 20 to 60 μm. When Rz <20 μm, the developer transportability is insufficient and the developability is insufficient. When Rz> 60 μm, the developer stress is large between the spike regulating member and the development transport body and in the development area, and the carrier Condyles are easily destroyed.

The measurement of Rz was based on JISBO601, the reference length L was 8 mm, and a surface roughness measuring device Surfcoder SE-30H (manufactured by Kobayashi Laboratories) was used.

FIG. 1 shows an example of a developing device equipped with the developer conveying body of the present invention, and FIG. 2 shows a copying machine in its entirety.

Auxiliary agents can be added to the developer used in the present invention for various performance modifications. For example, a coloring agent, a release agent, a cleaning improving agent, a charge controlling agent, a fluidizing agent, and the like are used.

As the coloring agent, for example, carbon black, chrome yellow, Dupont oil red, quinoline yellow, phthalocyanine blue, malachite green oxalate and the like can be used. The amount of the colorant to be used is generally 0.1 to 20 parts by weight based on 100 parts by weight of the binder resin.

As the release agent, for example, polyolefin,
Fatty ester wax, higher alcohol, paraffin wax, polyamide wax, etc.
JISK2531) A wax at 60 to 150 ° C is used.

As the cleaning improver, fatty acid metal salts, talc, graphite, mica, molybdenum disulfide, zinc white and the like can be used.

As the charge control agent, those conventionally known can be used, and examples thereof include a nigrosine dye and a metal-containing dye.

As the fluidizing agent, inorganic fine particles are used. For example, silica fine powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, Antimony oxide, magnesium oxide,
Zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like,
Silica fine powder is particularly preferred.

Further, in the present invention, these inorganic fine particles are preferably surface-treated with an amine-modified silicone compound such as an amino-modified silane coupling agent, an amino-modified silicone oil or a polysiloxane ammonium salt.

The average particle size of the primary particles of the inorganic fine particles thus obtained is preferably in the range of 3 μm to 2 μm.

The content ratio of the inorganic fine particles is 0.1% of the toner.
Preferably it is 1 to 5% by weight.

The inorganic fine particles whose surface has been treated with the amine-modified silicone compound as described above become inorganic fine particles having excellent positive chargeability, and have excellent moisture resistance and durability, and have stable positive friction independent of environmental conditions. It becomes inorganic fine particles having chargeability.

[0063]

Next, the present invention will be described in detail with reference to examples.

First, common matters will be described.

(1) Production of Crystalline Polyester Crystalline Polyester 1 1500 g of sebacic acid and 964 g of hexamethylene glycol were equipped with a thermometer, a stainless steel stirrer, a glass nitrogen gas inlet tube, and a flow condenser. Capacity 5
The flask was placed in a mantle heater, and nitrogen gas was introduced from a glass nitrogen gas inlet tube to raise the temperature while keeping the inside of the reactor under an inert atmosphere.

Then, 13.2 g of p-toluenesulfonic acid was added and reacted at a temperature of 150 ° C. When the amount of water distilled by the esterification reaction reaches 250 ml, the reaction is stopped,
The reaction system was cooled to room temperature to obtain a crystalline polyester 1 composed of polyhexamethylene sebacate having a hydroxyl group at a molecular terminal. The melting point Tm of this crystalline polyester 1 is 64
° C, the weight average molecular weight Mw was 14,000.

(2) Production of amorphous vinyl polymer Amorphous vinyl polymer 1 100 parts of toluene was placed in a separable flask having a capacity of 1 liter, and 75 parts of styrene as a monomer for a high molecular weight component was added thereto. , 25 parts of butyl acrylate and 0.2 parts of benzoyl peroxide were added, and the gas phase in the flask was replaced with nitrogen gas. Then, the temperature was raised to 80 ° C. and maintained at that temperature for 15 hours to carry out the first-stage polymerization. went. The homopolymer of the monomer for a high molecular weight component had Mw of 461,000 and Tg of 6
1 ° C.

Next, the inside of the flask was cooled to a temperature of 40 ° C., and styrene as a monomer for a low molecular weight component was placed therein.
85 parts, 10 parts of butyl methacrylate, 5 parts of acrylic acid and 4 parts of benzoyl peroxide were added, and the mixture was stirred at a temperature of 40 ° C. for 2 hours. For 8 hours to carry out the second stage polymerization. In addition, Mw of the homopolymer of the monomer for a low molecular weight component is 8,20.
0, Tg is 64 ° C.

Next, 0.5 g of zinc oxide, which is a polyvalent metal compound, was added to the flask, and the mixture was reacted at reflux temperature for 2 hours while stirring.

Further, toluene was distilled off with an aspirator and a vacuum pump to obtain an amorphous vinyl polymer 1 in which ionic cross-linking was formed by reaction of zinc oxide with a carboxyl group of the vinyl polymer. This amorphous vinyl polymer 1
Means that there are two peaks in the molecular weight distribution by GPC (363,000 high molecular weight, 7,590 low molecular weight), and Mw is 165,
000, value of ratio Mw / Mn is 25.9, Tg is 62 ° C., softening point Ts
p was 130 ° C.

(3) Production of Binder Resin Binder Resin 1 20 parts of crystalline polyester 1 and amorphous vinyl polymer 1
80 parts of p-toluenesulfonic acid 0.05 part and xylene 10
0 parts was placed in a separable flask having a capacity of 3 liters, refluxed at a temperature of 150 ° C. for 1 hour, and then xylene was distilled off with an aspirator and a vacuum pump, whereby the crystalline polyester and the amorphous vinyl polymer were separated. A chemically bonded binder resin 1 was obtained. The binder resin 1 had a glass transition point of 60 ° C. and a softening point of 110 ° C.

Binder resin 2 15 parts of crystalline polyester 1 and amorphous vinyl polymer 1
85 parts of p-toluenesulfonic acid 0.05 part, xylene 10
In the same manner as in the case of the binder resin 1, the crystalline polyester and the amorphous vinyl polymer are chemically bonded to obtain a binder resin 2 having a glass transition point of 61 ° C. and a softening point of 115 ° C. Was.

(4) Production of Toner Toner 1 100 parts of binder resin 1, 10 parts of carbon black "Mogal L" (manufactured by Cabot), and paraffin wax "Sazol wax H1" (manufactured by Sasol Marketing) 3 Parts, and 3 parts of an alkylenebisfatty acid amide “Hoechst wax C” (manufactured by Hoechst), are preliminarily mixed by a V-type mixer, melt-kneaded by a twin-screw kneader, cooled, coarsely ground, and then finely ground. The powder was pulverized and further classified by an air classifier to obtain a powder. Silica fine particles treated with a surface polysiloxane ammonium salt (hereinafter referred to as “surface-treated silica fine particles”) were added to 100 parts by weight of this powder in 1.1 parts.
And 0.1 part of zinc stearate, and mixed with a Henschel mixer to obtain Toner 1 having a volume average particle size of 8.5 μm.

Toner 2 A toner 2 having a volume average particle diameter of 8.5 μm was obtained in the same manner as in the production of the toner 1 except that the binder resin 1 was changed to the binder resin 2.

(5) Manufacture of Carrier Carrier 1 A spherical, porous magnetic material (apparent specific gravity: 3.5 g / cc) made of copper-zinc-based ferrite was coated on the surface with 2,2,2-trifluoroethyl methacrylate. As a result, a carrier 1 having an average particle size of 80 μm was obtained.

Carrier 2 An apparent specific gravity of 2.6 g / cc and an average particle size of 80 were obtained in the same manner as in Carrier 1.
A μm carrier 2 was obtained.

Carrier 3 Apparent specific gravity 3.9 g / cc, average particle size 80
A μm carrier 3 was obtained.

Carrier 4 (for Comparative Example) In the same manner as Carrier 1, apparent specific gravity was 4.1 g / cc, and average particle size was 80.
A μm carrier 4 was obtained.

Carrier 5 (for Comparative Example) Apparent specific gravity 2.4 g / cc, average particle size 80 in the same manner as Carrier 1
A μm carrier 5 was obtained.

(6) Preparation of Developer A two-component developer was prepared by mixing 96 parts by weight of the carrier and 4 parts by weight of the toner in the combination shown in the following table.

[0081]

[Table 1]

(7) Developing Device (The developing device shown in FIG. 1 was used.) Developer Transporter 1 The aluminum pipe was roughened by sandblasting to obtain a developer transporter 1 with Rz = 40 μm.

[0083] to obtain a developing agent conveying member 2-5 having the following R _Z in the same manner.

Developer transporter 2; Rz = 20 μm Developer transporter 3; Rz = 60 μm Developer transporter 4; Rz = 18 μm Developer transporter 5; Rz = 62 μm Image forming apparatus (using the apparatus shown in FIG. 2)・ Latent image carrier (organic photoconductor) Maximum potential -680V Circumferential speed 240mm / sec Outer diameter 100mm ・ Developer 450mm gap between developer carrier and latent image carrier Developer carrier and hot plate regulating plate 400 μm DC bias voltage applied to the developer carrier -150 V Peripheral speed of the developer carrier 613 mm / sec Outer diameter of the developer carrier Example 1 Developer 1 with developer carrier 1 2 in the image forming apparatus under normal temperature and normal humidity (20 ° C, 60% RH)
150,000 live-action tests were performed. After 150,000 times, the toner charge amount is 25 μc / g, which is almost the same as the initial value, and carrier contamination due to toner spent is small. Further, there was no filming on the developer carrier, the image density was high, and no destruction of the carrier was observed, and a good image was obtained up to 150,000 times.

Example 2 The developer 2 was put into the image forming apparatus shown in FIG. 2 having the developer transporter 1 and the same actual photographing test as in Example 1 was performed. As a result, good results were obtained as in Example 1. Obtained.

Example 3 The developer 3 was put into the image forming apparatus shown in FIG. 2 having the developer carrier 2 and the same actual photographing test as in Example 1 was performed. As a result, good results were obtained as in Example 1. Obtained.

Example 4 The developer 4 was put into the image forming apparatus shown in FIG. 2 having the developer conveying member 3 and a real photographing test similar to that of Example 1 was performed. Obtained.

Comparative Example (1) The comparative developer (1) was charged into the image forming apparatus shown in FIG. 2 having the developer carrier 1 and the same test as in Example 1 was performed. Markedly progressed, resulting in an unclear image in which the amount of charge of the toner decreased and fogged. Further, the image density gradually decreased due to filming on the developer conveying member.

Comparative Example (2) The comparative developer (2) was charged into the image forming apparatus shown in FIG. 2 having the developer carrier 1 and the same test as in Example 1 was performed. However, an unclear image with much carrier adhesion and fogging was obtained.

Comparative Example (3) The developer 1 was charged into the image forming apparatus shown in FIG.
The image density was low from the beginning.

Comparative Example (4) The developer 2 was charged into the image forming apparatus shown in FIG.
Carrier destruction progressed, resulting in an unclear image with much carrier adhesion and fogging.

Evaluation method (1) Charge amount of toner The charge amount of the toner was measured by a blow-off method through a 350 mesh stainless steel net. Blow pressure is 0.2kg / c
m ² , and the blow time was 6 sec.

(2) Degree of Carrier Contamination Only a carrier is separated from a developer by using a surfactant.
3.0 g of the carrier was placed in 100 ml of methyl ethyl ketone to dissolve the coating resin, and the transmittance of the solution at 500 nm was measured with a spectrophotometer (330 type Hitachi automatic recording spectrophotometer), and the value was defined as the degree of carrier contamination.

(3) Image density The maximum density (Dmax) was measured with a Sakura densitometer (manufactured by Konica).

Table 2 shows the above results.

[0096]

[Table 2]

[0097]

As described above, it is possible to provide an image forming method which does not hinder development due to abrasion of toner and carrier particles of a developer, has good developability, and has good low-temperature fixability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a developing device equipped with a developer conveying body of the present invention.

FIG. 2 is a schematic diagram of an example of a copying machine to which the developer conveying body of the present invention is applied.

[Explanation of symbols]

 11 Developer carrier 12 Standing member 16 Doctor blade 21 Band electrode 22 Developer 24 Cleaning blade 28 Fixer

──────────────────────────────────────────────────の Continued on front page (72) Inventor Yuriko Suzuki 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Corporation (72) Inventor Shinichi Nakamura 2970 Ishikawa-cho, Hachioji-shi, Tokyo Examiner in Konica Corporation Inoue Yaichi (56) Reference JP-A-4-321107 (JP, A) JP-A-63-27856 (JP, A) JP-A-61-120169 (JP, A) JP-A-1-134381 (JP, A A) JP-A-4-260072 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/087 G03G 9/113 G03G 15/08

Claims (1)

(57) [Claims] An electrostatic latent image developer, comprising: a toner having a binder in which a crystalline polyester and an amorphous vinyl polymer are chemically bonded; and an apparent specific gravity of 2.5 to 4.0 g / cc.
A developer containing a carrier coated with magnetic particles of a resin is loaded on a developer carrier having a 10-point average roughness Rz having a surface roughness of 20 to 60 μm, and is conveyed to a development area, where a latent image is carried. An image forming method comprising developing an electrostatic charge image formed on a body.