JPH0545929A - Image formation - Google Patents

Abstract

PURPOSE:To perform low temp. fixing without any trouble with development due to worn toner or carrier particles by conveying a developer including a toner excelling in low temp. fixation and resistance to offset and a magnetic substance particle carrier put on a developer conveying body with the specified roughness to a development zone and by developing an electrostatic charge image. CONSTITUTION:With the use of block copolymers of crystalline polyester and amorphous vinyl polymers or binder resins including the block copolymers, a toner excelling in low temp. fixation and resistance to offset is obtained. Developing material including the toner and a carrier which magnetic substance particles of 2.5-4.0g/cc apparent specific gravity are covered with a resin to form is put on a developer conveying body 11 of 20-60mum surface roughness and conveyed to a developing zone to develop an electrostatic charge image formed on a latent image bearing member.

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, a latent image carrier is usually charged and exposed to form an electrostatic latent image, the electrostatic latent image is developed with toner, and the obtained toner image is transferred onto a transfer paper. A visible image is formed by transferring and fixing to a support such as.

Recently, (a) prevention of thermal deterioration of the photosensitive member, (b) reduction of warm-up type, (c) retention of temperature of heat roller in continuous copying for a long time, (d) curl phenomenon of paper, prevention of jamming. Therefore, there is a strong demand for enabling the fixing process with the temperature of the heat roller being lowered. Therefore, it is necessary for the toner to be well fixed at a low temperature.

Further, the toner is required to have excellent blocking resistance, and further, the heat roller fixing method is required to have offset resistance.

Due to such demands, many studies have been conducted on the toner for low temperature fixing, for example, Japanese Patent Laid-Open No.
Nos. 50-87032 and 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 have 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 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 is Poorly, it causes an unclear image and image deterioration.

Further, as a method of improving the triboelectric chargeability between a carrier and a toner in a two-component developer, it is known to include a charge control agent in the toner and to coat the surface of the carrier with a fluorine resin. -229158).

However, when used in combination with a conventional toner, none of them sufficiently satisfies both low temperature fixing property and anti-offset property.

A triboelectric charge control layer further containing a block copolymer or graft copolymer of a crystalline polyester and an amorphous vinyl polymer, and the carrier core material contains a fluorinated alkyl (meth) acrylate polymer. There is a proposal of coating with (Japanese Patent Laid-Open No. 2-186360).

However, although the carrier is coated with a fluorinated alkyl (meth) acrylate polymer having a low surface energy to suppress the toner spent, it contains a large amount of a substance that melts at a low temperature. It is inevitable that the toner will be spent on the carrier due to the internal stress. Further, since the crystalline polyester in the binder resin is filmed on the developer carrying member, the developer carrying amount is reduced, resulting in a decrease in image density, image density unevenness, and a difference in front and rear edge density (a leading edge of a solid black image and There is a problem that the density difference at the trailing edge) becomes large.

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

The metal magnetic carrier used as a conventional carrier has a large specific gravity (1) and a large mixing and stirring torque at the time of frictional charging with the toner.

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

There are problems such as

To solve the above problems, Japanese Patent Laid-Open No. 58-23032 discloses that ferrite oxides such as nickel oxide, zinc oxide and iron oxide, which have a smaller specific gravity than metals such as iron (specific gravity: about 5).
g / cc) and by selecting conditions such as the spray drying method to create ferrite carrier particles, introducing cavities into the particles to reduce the stirring torque when mixing the developer and reduce the life of the developer. Techniques for stretching 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, and the particles are destroyed during mixing and stirring, and the developer life is shortened.
Therefore, from the viewpoint of life, the porosity of 4 to 40% is preferable.

However, the porosity of the ferrite carrier is 4
At 40%, the mechanical stress in the developing device is reduced, but the carrier mechanical strength is weak and the carrier is destroyed, so filming of carrier slag and fogging occur.

[0017]

SUMMARY OF THE INVENTION The object of the present invention is to provide a low-temperature fixing in which the toner spent is small, the development constancy is long, the filming of the toner on the developer carrier is mechanically small, and the carrier is not destroyed. A possible image forming method is provided.

[0018]

The object of the present invention is: a toner containing a resin in which a crystalline polyester and an amorphous vinyl polymer are chemically bound in an electrostatic latent image developer as a binder, and an apparent specific gravity of 2.5 to 4.0. A developer containing a carrier formed of a resin containing g / cc of magnetic particles and having a surface roughness of 20 to 60.
and an electrostatic charge image formed on a latent image carrier is developed by being carried on a developer carrier having a 10-point average roughness Rz of .mu.m and conveyed to a developing area. ..

The present invention will be described in detail below.

The toner constituting the electrostatic image developer of the present invention contains, as a binder resin thereof, a block copolymer or a graft copolymer of a crystalline polyester and an amorphous vinyl polymer. At the time 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 fixability 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 polyethylene sebacate, polyethylene adipate, polyethylene suberate, polyethylene succinate, polyethylene-p- (carbophenoxy) undecaate, polyhexamethylene oxalate, polyhexamethylene. Sebacate, polyhexamethylene decandioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene oxalate, polydecamethylene sebacate,
Polydecamethylene succinate, polydecamethylene dodecanedioate, polydecamethylene octadecanedioate, polytetramethylene sebacate, polytrimethylene dodecanedioate, polytrimethylene octadecanedioate, polytrimethylene oxalate, polyhexamethylene -Decamethylene-sebacate, polyoxydecamethylene-2-methyl-1,3-propane-dodecanedioate and the like can be mentioned.

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 toner obtained has poor blocking resistance, and the crystalline polyester has a melting point of 120 ° C.
If it exceeds, the melt fluidity of the toner at low temperature may be deteriorated and the fixing property 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 bound to the amorphous vinyl polymer.

When the weight average molecular weight Mw of the above 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 good.

The crystalline polyester is used in an amount of 3 to 50 wt% in a block polymer or a graft copolymer with an amorphous vinyl polymer in order to obtain a low minimum fixing temperature and a high temperature offset resistance in the toner. 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 type monomers, acrylic acid ester type monomers and methacrylic acid ester type monomers. It is obtained by using at least one of

Examples of the styrene-based 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 acrylic acid ester-based monomer include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic acid- Examples thereof include 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, and α-chloromethyl acrylate.

Examples of the above-mentioned methacrylic acid ester-based monomers include methyl methacrylate, ethyl methacrylate,
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. If

Examples of the monomer 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, phthalic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxyethyl ester, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, p-aminostyrene, glycidyl methacrylate, etc. .. The monomer having such a functional group is used in the range of 0.1 to 20 mol% in the monomer composition for obtaining the amorphous vinyl polymer.

The amorphous vinyl polymer used in the present invention is preferably a vinyl polymer having a carboxyl group in which a polyvalent metal compound reacts with the carboxyl group to form an ionic cross-linkage 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 a vinyl polymer, for example, the polyvalent metal compound is mixed with a solution containing a vinyl polymer having a carboxyl group obtained by polymerization by a solution polymerization method, and the temperature is raised. The temperature inside the reaction system is 150-180 ℃
It is recommended to maintain this temperature for 1 hour or more to complete the reaction when the temperature reaches a certain level.

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

The above-mentioned high molecular weight component makes the amorphous vinyl polymer tougher and prevents the toner particles from being broken by a mechanical external force such as friction with the carrier or stirring in the developing device. The generation of causative fines is controlled. The proportion of the high molecular weight component in the amorphous vinyl polymer is preferably 15 wt% or more.

Further, the destruction of the toner particles caused by the friction with the carrier or the mechanical external force such as stirring in the developing device is mainly due to the relatively fragile component having a low molecular weight in the toner particles. It is preferable to ion-crosslink the molecular weight component to make it tough and to impart fracture resistance to the toner particles.

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

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

Furthermore, the softening point of the amorphous vinyl polymer is preferably 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 crystalline polyester and the amorphous vinyl polymer, for example, a head-to-tail reaction is performed by a coupling reaction between terminal functional groups present in each polymer. Can be directly coupled to each other in a fashion. Alternatively, it can be bound to the terminal functional group of each polymer by a bifunctional coupling agent, and as the bifunctional coupling agent, for example, diisocyanate,
Examples thereof include dicarboxylic acid, glycol, phosgene, dichlorodimethylsilane and the like.

In the present invention, it is preferable that the above-mentioned copolymer is contained in at least 5 wt% of the total toner.

The carrier used in the developer of the present invention is magnetic particles having an apparent specific gravity of 2.5 to 4.0 g / cc coated with a resin. If the specific gravity is less than 2.5, the mechanical strength is insufficient and the carrier Destruction, filming of generated carrier slag, generation of fogging, etc. Also, when it exceeds 4.0, the stress applied to the toner becomes large, the toner is crushed, toner scatter occurs, and development constancy is lost.

Here, the apparent specific gravity is the specific gravity including pores.

The magnetic substance is a ferrite which is a sintered body of an oxide of iron such as zinc, manganese, copper, magnesium, lithium, barium and the like, and is porous with many pores in the sintered body. It is the body.

The resin used for coating the carrier is a fluorine-based resin such as vinylidene fluoride-tetrafluoroethylene copolymer, tetrafluoroethylene, 2,2,2-trifluoroethyl methacrylate, pentafluoropropyl methacrylate and the like. ,
Styrene resins, acrylic resins, silicone resins, etc. are 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 in which resin powder is struck and attached by mechanical impact force, and the like are used.

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

The particle size is Microtrac (Type 7981
-OX; manufactured by Lead & Northrup Co., Ltd.).

The apparent specific gravity was measured by a constant volume expansion method multivolume densitometer 1305 (manufactured by Micromeritics).

For the developer carrier applied to the present invention, a nonmagnetic, conductive metal, for example, a cylinder of aluminum, brass or the like having a wall thickness of 0.5 to 1.5 mm is used. The surface is roughened to have a point average roughness Rz of 20 to 60 μm. When Rz <20 μm, the developer transportability is insufficient and the developability is insufficient, and when Rz> 60 μm, the stress of the developer received between the spike control member and the developer transport body and in the developing region is large, and The condyles are easily destroyed.

The Rz was measured in accordance with JIS BO601, with a standard length L of 8 mm, and a surface roughness measuring instrument Surfcoder SE-30H (manufactured by Kobayashi Laboratory) was used.

An example of a developing device equipped with the developer carrier of the present invention is shown in FIG. 1, and the entire copying machine is shown in FIG.

An auxiliary agent may be added to the developer used in the present invention in order to modify various properties. For example, a colorant, a release agent, a cleaning property improver, a charge control agent, a fluidizing agent and the like are used.

As the colorant, 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 used is usually 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin.

As the releasing agent, for example, polyolefin,
Softening point (ring and ball method) such as fatty acid ester wax, higher alcohol, paraffin wax, polyamide wax
JISK2531) Wax at 60 to 150 ° C is used.

As the cleaning property improver, fatty acid metal salt, talc, graphite, mica, molybdenum disulfide, zinc white, etc. can be used.

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

Inorganic fine particles are used as the fluidizing agent. 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, three Antimony oxide, magnesium oxide,
Examples include zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc.
Fine silica 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 particle size of the inorganic fine particles thus obtained is preferably such that the average particle size of the primary particles is within the range of 3 μm to 2 μm.

The content ratio of the inorganic fine particles is 0.
It is preferably 1 to 5 wt%.

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 charging property, excellent moisture resistance and durability, and stable positive friction which is not affected by environmental conditions. The inorganic fine particles have a charging property.

[0063]

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

First, common items will be described.

(1) Production of crystalline polyester Crystalline polyester 1 1500 g of sebacic acid and 964 g of hexamethylene glycol were provided with a thermometer, a stirrer made of stainless steel, a nitrogen gas introduction pipe made of glass and a fluidized condenser. Capacity 5
It was placed in a liter round-bottomed flask, and then this flask was placed in a mantle heater, and nitrogen gas was introduced through a nitrogen gas introduction tube made of glass to raise the temperature while keeping the inside of the reactor in 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 made of polyhexamethylene sebacate having a hydroxyl group at the molecular end. The melting point Tm of this crystalline polyester 1 is 64.
C., the weight average molecular weight Mw was 14,000.

(2) Manufacture of amorphous vinyl polymer Amorphous vinyl polymer 1 A separable flask having a volume of 1 liter was charged with 100 parts of toluene, and 75 parts of styrene as a monomer for a high molecular weight component were added thereto. , 25 parts of butyl acrylate and 0.2 part 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 the temperature was maintained for 15 hours to carry out the first stage polymerization. went. The homopolymer of this high molecular weight component monomer had a Mw of 461,000 and a Tg of 6
It is 1 ℃.

Then, the inside of the flask was cooled to a temperature of 40 ° C., and styrene was added as a monomer for the low molecular weight component.
After adding 85 parts, 10 parts of butyl methacrylate, 5 parts of acrylic acid and 4 parts of benzoyl peroxide and continuing stirring at a temperature of 40 ° C for 2 hours, the temperature was raised again to 80 ° C and the temperature was increased. The second stage polymerization was carried out for 8 hours. The Mw of the homopolymer of this low molecular weight component monomer was 8,20.
0 and Tg are 64 ° C.

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

Further, toluene was distilled off by an aspirator and a vacuum pump to obtain an amorphous vinyl polymer 1 in which zinc oxide reacted with a carboxyl group of the vinyl polymer to form an ionic cross-linkage bond. This amorphous vinyl polymer 1
Has two peaks in the molecular weight distribution by GPC (high molecular weight side 363,000, low molecular weight side 7,590), Mw is 165,
000, ratio Mw / Mn value 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 parts of xylene 10
0 part was placed in a separable flask having a capacity of 3 liters, refluxed at a temperature of 150 ° C. for 1 hour, and xylene was distilled off by an aspirator and a vacuum pump to obtain a crystalline polyester and an amorphous vinyl polymer. Binder resin 1 chemically bonded 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 parts of xylene 10
In the same manner as the binder resin 1, the crystalline polyester and the amorphous vinyl polymer are chemically bonded to each other to give a binder resin 2 having a glass transition point of 61 ° C. and a softening point of 115 ° C. It was

(4) Manufacture of Toner 1 Toner 1 100 parts of binder resin 1, 10 parts of carbon black "Mogal L" (manufactured by Cabot), paraffin wax "Sazol Wax H1" (manufactured by Sazol Marketing) 3 Parts and 3 parts of alkylenebis fatty acid amide "Hoechst wax C" (manufactured by Hoechst) are premixed by a V-type mixer, melt-kneaded by a biaxial kneader, cooled, coarsely crushed, and then finely ground. The powder was crushed and further classified by an air classifier to obtain a powder. To 100 parts by weight of this powder, 1.1 parts of silica fine particles treated with a surface polysiloxane ammonium salt (hereinafter referred to as "surface-treated silica fine particles") were prepared.
And 0.1 part of zinc stearate were added and mixed by a Henschel mixer to obtain a toner 1 having a volume average particle diameter 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) Production of Carrier Carrier 1 A spherical and porous magnetic substance (apparent specific gravity of 3.5 g / cc) made of copper-zinc type ferrite is coated with 2,2,2-trifluoroethyl methacrylate on its surface. Thus, a carrier 1 having an average particle size of 80 μm was obtained.

Carrier 2 Similar to Carrier 1, apparent specific gravity is 2.6 g / cc, average particle size is 80
A carrier 2 of μm was obtained.

Carrier 3 Similar to Carrier 1, apparent specific gravity is 3.9 g / cc, average particle size is 80
A carrier 3 of μm was obtained.

Carrier 4 (for Comparative Example) As in Carrier 1, apparent specific gravity is 4.1 g / cc, average particle size is 80.
A carrier 4 of μm was obtained.

Carrier 5 (for Comparative Example) As in Carrier 1, apparent specific gravity is 2.4 g / cc and average particle size is 80.
A carrier 5 of μm was obtained.

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

[0081]

[Table 1]

(7) Developing Device (Using the Developing Device Shown in FIG. 1) Developer Carrier 1 An aluminum pipe was roughened by sandblasting to obtain a developer carrier 1 with Rz = 40 μm.

Similarly, developer carriers 2 to 5 having the following R _Z were obtained.

Developer carrier 2; Rz = 20 μm Developer carrier 3; Rz = 60 μm Developer carrier 4; Rz = 18 μm Developer carrier 5; Rz = 62 μm Image forming apparatus (use the device shown in FIG. 2・ Latent image carrier (organic photoconductor) Maximum potential −680V Peripheral speed 240mm / sec Outer diameter 100mm ・ Developer Gap between developer carrier and latent image carrier 450μm Developer carrier and spike control plate Gap of 400 μm DC bias voltage applied to developer carrier −150 V Peripheral speed of developer carrier 613 mm / sec Outer diameter of developer carrier 40 mm Example 1 Developer 1 and developer carrier 1 In an image forming apparatus of No. 2, under normal temperature and humidity environment (20 ℃, 60% RH)
150,000 live-action tests were conducted. The toner charge amount after 150,000 times is 25 μc / g, which is almost the same as the initial amount, and carrier contamination due to toner spent is small. Further, there was no filming on the developer transport body, the image density was high, and the carrier was not destroyed, and good images were obtained up to 150,000 times.

Example 2 The developer 2 was put into the image forming apparatus having the developer transporting body 1 shown in FIG. 2 and a real copying test similar to that in Example 1 was conducted. As a result, the same good result as in Example 1 was obtained. Was obtained.

Example 3 When the developer 3 was put into the image forming apparatus having the developer transporting body 2 shown in FIG. 2 and a real copying test similar to that of the example 1 was conducted, the same good result as that of the example 1 was obtained. Was obtained.

Example 4 When the developer 4 was put into the image forming apparatus having the developer transporting body 3 shown in FIG. 2 and a real copying test similar to that in Example 1 was conducted, the same good result as in Example 1 was obtained. Was obtained.

Comparative Example (1) The comparative developer (1) was put into the image forming apparatus having the developer carrier 1 shown in FIG. 2 and the same test as in Example 1 was conducted. As a result, carrier contamination by toner spent was observed. Markedly progresses, resulting in an unclear image in which the toner charge amount is reduced and there is much fogging. Also, the image density gradually decreased due to filming on the developer transport body.

Comparative Example (2) The comparative developer (2) was put into the image forming apparatus of FIG. 2 having the developer carrier 1 and the same test as in Example 1 was conducted. However, it became an unclear image with a lot of carrier adhesion and fogging.

Comparative Example (3) The developer 1 was put into the image forming apparatus of FIG. 2 having the developer transport body 4 and the same test as in Example 1 was conducted.
The image density was low from the beginning.

Comparative Example (4) The developer 2 was charged into the image forming apparatus of FIG. 2 having the developer carrier 5 and the same test as in Example 1 was conducted.
The destruction of the carrier progressed, resulting in an unclear image with a lot of carrier adhesion and fogging.

Evaluation method (1) Toner charge amount The toner charge amount was measured by a blow-off method through a 350 mesh stainless mesh. Blow pressure is 0.2kg / c
m ² and blow time were 6 seconds.

(2) Carrier Contamination Degree The carrier alone is separated from the developer using a surfactant,
3.0 g of the carrier was put into 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 Hitachi self-recording spectrophotometer), and the value was taken as the carrier contamination degree.

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

The above results are shown in Table 2.

[0096]

[Table 2]

[0097]

EFFECT OF THE INVENTION It is possible to provide an image forming method having a good developing property, which does not hinder the development due to the abrasion of the developer toner and carrier particles, and has a good low temperature fixing property.

[Brief description of drawings]

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

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

[Explanation of symbols]

 11 developer carrier 12 spike-up restraining member 16 doctor blade 21 strip electrode 22 developing device 24 cleaning blade 28 fixing device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location 7144-2H G03G 9/10 351 (72) Inventor Tatsuya Nagase 2970 Ishikawacho, Hachioji, Tokyo Konica Stocks In-company (72) Inventor Yuriko Suzuki 2970 Ishikawa-cho, Hachioji, Tokyo Konica stock company (72) Inventor Shinichi Nakamura 2970 Ishikawa-cho, Hachioji, Tokyo Konica stock company

Claims (1)

[Claims] 1. An electrostatic latent image developer comprising a toner containing a resin in which a crystalline polyester and an amorphous vinyl polymer are chemically bound, and an apparent specific gravity of 2.5 to 4.0 g / cc.
The developer containing the magnetic particles of the above-mentioned carrier coated with a resin is carried on a developer carrier having a 10-point average roughness Rz having a surface roughness of 20 to 60 μm and carried to the developing area to carry a latent image. An image forming method comprising developing an electrostatic charge image formed on a body.