JP3253042B2 - Non-magnetic two-component developer and developing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry non-magnetic two-component developer for developing an electrostatic latent image used in electrophotography, electrostatic printing, and the like, and a method for developing the same.

[0002]

2. Description of the Related Art There are two types of dry developing methods employed in electrophotography and electrostatic printing, for example, a method using a two-component developer composed of a toner and a carrier, and a method using a one-component developer using only a toner. There is. In the two-component developing method, a relatively stable and good image can be obtained, but in general, a magnetic carrier is contained in the developer for performing magnetic brush development.
The disadvantage is that the developing device is heavy and large.
Further, the carrier contained in the two-component developer functions not only as a toner conveying member but also as a toner charging member. However, there is a problem that the so-called toner spent, in which the carrier is contaminated by the toner material, reduces the chargeability. is there.

There is a cascade developing system as a two-component developing system using a non-magnetic carrier, but it is hardly used at present due to an increase in the size of a developing device and insufficient image gradation. The one-component developer does not contain a carrier, so there is an advantage that the developing device can be made lighter and smaller.However, the toner is charged by frictional charging with the developer carrier and the toner layer thickness regulating member. The quantity is likely to be insufficient. For example, since the charge amount of the toner newly replenished to the developer carrier after developing a character is insufficient, an afterimage phenomenon occurs in which the image portion corresponding to that portion becomes dark or the background portion becomes dirty during the next development. There are cases. Further, since the surface area of the triboelectric charging member is very small as compared with the surface area of the carrier of the two-component system, the deterioration of the charging property is fast, and the change of the image is generally large in the one-component developing method compared to the two-component developing method. Further, in the one-component developing method, there is a movement to make the toner layer multilayer after passing through the toner layer thickness regulating member in order to make the image density uniform and obtain a sufficient image density. This is likely to occur and the image is likely to change.

[0004] This one-component developer developing method, that is, a developing device essentially comprising at least a developer carrier, a toner layer thickness regulating member provided in contact with the developer carrier, and an electrostatic latent image carrier is essentially provided. Japanese Patent Application Laid-Open No. Sho 62-969 proposes a proposal for improving the disadvantage of insufficient ability to apply charge to toner.
Japanese Patent Application Laid-Open No. 56-56760 discloses a developing device comprising a magnetic carrier, a developer carrying member having a magnetic field generating means therein, and a toner layer thickness regulating member. A developing device in which a regulating member is disposed at a position avoiding the above-mentioned condition to improve the circulation of the carrier is shown. However, it is difficult to reduce the weight of a two-component developer using a magnetic carrier because the true specific gravity of the magnetic carrier is large, and the so-called toner spent that contaminates the carrier surface with the toner component due to a large collision energy with the toner is likely to occur. ,
The charging performance of the developer is likely to deteriorate. Further, since the magnetic field generating means is inscribed inside the developer carrier, the magnetic carrier rotates and moves under the magnetic binding force, thereby increasing toner spent development, shortening the durability of the developer, and improving stability and reliability. Development method is not high. At the same time, the cost of the device is increased. Normally, the toner and the carrier particles have a distribution in the particle diameter. When the carrier is regulated by the regulating member, the minimum particle diameter of the carrier must be at least larger than the maximum particle diameter of the toner.
Therefore, the average particle size of the carrier increases, and the surface area of the carrier per weight decreases. Therefore, in order to sufficiently triboelectrically charge the toner, a considerably large amount of carrier is required for the toner. It will be difficult.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel dry non-magnetic two-component developer in which the above-mentioned drawbacks of the conventional dry two-component developing method and dry one-component method are improved, and a developing method thereof. The purpose is. In other words, providing a lightweight and compact developing device, providing a highly durable two-component developer with a small amount of toner spent on the carrier, imparting sufficient triboelectrification to the toner, and providing stable and satisfactory without remaining or background contamination To provide a developing method for maintaining a stable image for a long period of time, and to provide sufficient triboelectrification to the toner even when the toner layer is multi-layered after passing through the toner layer thickness regulating member, and to stably maintain a good image for a long period of time. It is an object of the present invention to provide a developing agent and a developing method which are capable of performing the following.

[0006]

Means for Solving the Problems The constitution of the non-magnetic two-component developer of the present invention for solving the above-mentioned problems contains at least a binder resin and a coloring agent, does not contain a magnetic substance, and has a volume average particle diameter. The ratio dV / dn between dV and the number average particle diameter dn is 1 ≦ dV
/Dn≦1.2 and a carrier which does not contain a magnetic material capable of being charged to the opposite charging polarity to the toner and has a volume average particle diameter of the toner. The particle size is 5 times or less the particle size, and the minimum particle size in the particle size distribution is 1.5 times or more the maximum particle size of the toner.

The particle diameters of the toner and the carrier are values measured with a Coulter Multisizer. Further, the developing method of the present invention for achieving the above object provides at least a developer carrier, a toner layer thickness regulating member provided in contact with the developer carrier, and a contact layer provided in contact or non-contact with the developer carrier. A non-magnetic two-component developer is carried on the developer carrying member in a developing device comprising the electrostatic latent image carrying member,
After a thin layer substantially composed of only toner is formed on the developer carrying member after passing through the toner layer thickness regulating member, the toner is attracted to the electrostatic latent image by an electrostatic action. Also, in the conventional one-component developing method, the toner layer after the toner layer thickness regulating member has been multi-layered in order to make the image density uniform and obtain a sufficient image density. Since the amount of toner that cannot be sufficiently frictionally charged with the body and the toner layer thickness regulating member increases, afterimages and background stains are likely to occur. Further, if the chargeability deteriorates due to the contamination of the developer carrying member and the toner layer thickness regulating member by the toner due to the repetition of the development, this phenomenon is accelerated and the change in the image quality of the image portion becomes remarkable.

In such a toner multi-layer carrying system, the present invention shows more remarkable effects. The toner in the developer of the present invention is preliminarily charged with carrier particles. However, the surface of the developer carrier or the surface of the toner layer thickness regulating member is made of a material having the same charge polarity as the carrier to the toner. Stable and sufficient charge can be imparted to the toner, and a good and stable image can be provided. One of the features of the developer of the present invention is to use a non-magnetic carrier, which prevents the deterioration of the carrier, that is, the destruction of the toner spent or the carrier coating layer, and improves the durability of the developer. The purpose is. Many of these causes of deterioration of two-component developers using conventional magnetic carriers have a large collision energy due to the large specific gravity of the magnetic material, and a large force is applied to the magnetic field to transport the developer by the magnetic binding force. It is brought by being given. As the carrier in the developer of the present invention, a non-magnetic material having a low true specific gravity can be used. Particularly, when the true specific gravity is 1.5 g / cm ³ or less, such as resins, the durability is more remarkable. Improve the performance.

The main reason that the dry two-component developing device cannot be made smaller and lighter than the one-component developing device is that it uses carrier particles having a large true specific gravity and a particle size considerably larger than that of the toner. In general, the two-component developing method is a magnetic brush developing method, and the carrier itself is heavy because a magnetic material having a high true specific gravity such as iron, magnetite, or ferrite is used for the carrier in the developer. Also,
In the magnetic brush developing method, if the carrier particle size is reduced, the carrier is also developed.
A carrier having a particle size as large as 20 times is used, and the surface area per unit weight is much smaller than that of the toner. The coverage of the toner with respect to the carrier for imparting proper chargeability to the toner is 20 to 40%, and generally requires a carrier 20 to 50 times the weight of the toner.

As the carrier particles in the non-magnetic two-component developer of the present invention, a non-magnetic material having a low specific gravity can be used. Further, since a carrier having a volume average particle size of 5 times or less the toner volume average particle size is used, the developer However, it is light and requires only a small amount, so that the size and weight of the developing device itself can be reduced. In the developing method described below, the minimum particle diameter in the particle diameter distribution of the carrier particles of the present invention is 1.5 times or more the maximum particle diameter of the toner. As a result, a thin layer consisting of only the toner can be formed.
The carrier particles used in the present invention satisfy the above conditions,
Further, any material can be used as long as it can provide a desired charge to the toner, but a material having a low true specific gravity is desirable. Also,
A so-called coated carrier may be used in which the surface of the carrier is coated by a conventionally known method to control the chargeability, adhesion, and strength. The material of the carrier particles used in the present invention is, for example, various kinds of inorganic substances such as glass, alumina, silicon nitride, silicon carbide, zirconia, beryllia, magnesia,
There are mullite, zeolite, silica sand, shirasu, and the like, and examples of organic substances include resins such as polyvinyl chloride, polyacrylamide, polyimide, polyethylene, polypropylene, polystyrene, tetrafluoroethylene, epoxy urethane, and silicone acrylic.

Of these, those having a low true specific gravity and a shape close to a sphere and having a narrow particle size distribution are particularly preferred. Therefore, resins which are spherically granulated from the pulverized product and have a uniform particle size distribution by classification or the like and have a true specific gravity of 1.5 g / cm ³ or less are preferably used. The carrier coating material is a fluorine compound,
Conventionally known materials such as silicon compounds and various resins can be used. The toner particles used in the present invention have a ratio dV / dn between the volume average particle diameter dV and the number average particle diameter dn of 1 ≦ dV /
dn ≦ 1.2. The dV / dn of a conventional general toner is about 1.4 to 2.0, so that it is necessary to further classify the toner to obtain the toner of the present invention, but the yield is reduced and the cost is increased. Resin particles having a narrow particle size distribution can be obtained by the so-called dispersion polymerization method disclosed in JP-A-61-18965, and the toner of the present invention can be easily produced by using the resin particles.

The binder resin used in the toner of the present invention includes styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and homopolymers of substituted styrenes: styrene-p-chlorostyrene copolymer, styrene -Propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-
Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Styrenic copolymers such as maleic acid copolymer and styrene-maleic acid ester copolymer: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin , Polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin,
Phenol resins, aliphatic or aliphatic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc., can be used alone or in combination.

When a toner is produced by a dispersion polymerization method, a copolymer of the above-mentioned styrene monomer and alkyl (meth) acrylate monomer is preferably used. Examples of the coloring material used in the present invention include carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, and rhodamine 6.
Any conventionally known dyes and pigments such as G, lake, chaco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo dye and disazo dye can be used alone or in combination.

When a toner is produced by a dispersion polymerization method, the above-mentioned oil-soluble dyes are preferably used. The developing method of the present invention comprises at least a developer carrier, a toner layer thickness regulating member provided in contact with the developer carrier, and an electrostatic latent image carrier. In such a developing method, when a conventional one-component toner is developed, the small-diameter toner in the toner preferentially passes through the toner layer thickness regulating member, and the particle size distribution of the remaining toner shifts to a larger one, and the image density changes. There was a problem and the charge of the toner was insufficient, resulting in afterimages and background stains.

On the other hand, dV / dn of the toner is 1 ≦ dV
/Dn≦1.2, the particle size distribution is narrowed, and even if carrier particles having 1.5 times or more of the maximum particle size of the toner are mixed, the developer on the developer carrier after passing through the toner layer thickness regulating member is substantially Was found to be a toner component. Further, they have found that the charge can be sufficiently and stably given to the toner by positively imparting the charge imparting function to the carrier particles. Further, by using a non-magnetic material having a particle size of 5 times or less the toner particle size and a small true specific gravity, the developer can be reduced in weight and amount, and the developing device itself can be reduced in size and weight. It became.

An example of a developing apparatus suitable for carrying out the present invention will be described in detail with reference to FIG. 1. The developer carrying member 2, the toner layer thickness regulating member 3, and the electrostatic latent image carrying member One as a main component, and the layer thickness regulating member 3 is particularly important. The figure also shows a toner stirring device 5, a developer 6, and a developer holder 7.

Toner Production Example 1 [Production of Chargeable Resin Particles] Condenser, nitrogen inlet tube, 4
Two stainless turbine blades with four blades inclined at 5 degrees (the diameter of the blade is 2/3 of the diameter of the reaction vessel), a glass motor equipped with a stirring motor, a dropping funnel, a thermometer, and a syringe inlet. The following were charged into a reaction vessel.

Methanol 60 parts Ethanol 20 parts Distilled water 10 parts Maleic anhydride-methyl vinyl ether copolymer (weight average molecular weight 150,000) 1.5 parts Partial esterification by heating and stirring at 70 ° C. for 5 hours to give anhydrous The maleic acid-methyl vinyl ether copolymer was dissolved. The reaction vessel was immersed in a constant temperature water bath capable of controlling the temperature to a preset temperature of ± 0.1 ° C., and cooled to 5 ° C., and nitrogen was introduced into the system from a nitrogen introduction pipe. The oxygen concentration in the system was replaced with 0.1% by volume or less by detecting the oxygen concentration in the gas phase with a galvanic cell type oxygen analyzer. When the temperature in the system reached 5 ° C., the following were charged from the dropping funnel.

Styrene 35 parts n-butyl methacrylate 15 parts n-dodecyl mercaptan 0.35 parts divinylbenzene (converted to active ingredient 100%) 0.5 parts The oxygen concentration in the system increased to 0.5%. Further, nitrogen gas was supplied to replace the gas to 0.1% volume or less. Here, the temperature of the thermostatic bath was raised to 65 ° C. When the temperature in the reactor reached 60 ° C., the stirring speed was set to 100 rpm, and the following initiator solution was injected using a syringe.

2,16′-azobis (2,4-dimethylvaleronitrile) 0.0016 part Methanol 0.02 part After about 15 minutes, the clear solution starts to become cloudy, and then is left for 30 minutes, When the cloudiness in the system further increased, the following solution was dropped from the dropping funnel over 15 minutes. 2,2'-Azobis (2,4-dimethylvaleronitrile) 0.8 part Methanol 10 parts After continuing polymerization for about 5 hours and a half, the following mixture was injected using a syringe.

Α-thioglycerol 0.4 part 1,3-butanediol methacrylate 0.6 part methanol 5 parts When the reaction was further continued for 10 hours, a part of the solution was sampled with a syringe so as not to evaporate the liquid. Polymerization was inhibited by a small amount of hydroquinone,
The solid content was quantified by drying under reduced pressure at a constant temperature of 50 ° C., and the conversion was determined in consideration of the added amounts of the dispersion stabilizer and the polymerization initiator. As a result, the conversion was 79.2%.

Lower the set temperature of the constant temperature water bath,
After cooling the reactor until the following protrusion-forming monomer,
The composition was dropped from the dropping funnel over 2 hours. t-Butylacrylamide sulfonic acid 1 part Methyl methacrylate 19 parts Methanol 40 parts Distilled water 5 parts At the end of dropping, the stirring speed was set to 70 rpm, the temperature in the reactor was raised to 50 ° C., and 1 hour passed. By the way, the following turbid liquid was dropped from the dropping funnel over 30 minutes.

2,2′-azobisisobronitrile 0.4 part Methanol 7 parts The reaction is allowed to proceed at 50 ° C. for 3 hours, then the temperature in the reactor is raised to 65 ° C. over 1 hour, and the reaction is carried out for 20 hours. As a result, a cloudy dispersion was obtained. 98.7 conversion
% Had been reached. In addition, a very small portion of the obtained dispersion is diluted with a large excess of distilled water, and after centrifugal sedimentation, redispersed in distilled water, and the polymer particles that have been purified by removing unreacted substances, dispersants, etc. are scanned. Observation with a scanning electron microscope revealed spherical particles having a uniform particle size.

[Coloring] 4 parts of oil black 860 (manufactured by Orient Chemical Co., Ltd.), 8 parts of methanol were mixed, dissolved by heating, cooled, mixed with 100 parts of the previously prepared resin particle dispersion, and stirred at 40 ° C. for 2 hours. After cooling, the mixture was centrifuged and the supernatant was removed to remove 50 parts of methanol and 5 parts of water.
The operation of redispersing in 0 parts of the mixed solvent was performed three times to wash the resin particles by coloring. 99.7 parts of a powder obtained by drying this colored particle dispersion slurry with a small spray dryer (Yamato Mini Spray, manufactured by Yamato Scientific Co., Ltd.) was added to hydrophobic silica R.
972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed in a mixer to obtain a negatively chargeable toner A of the present invention. The volume average particle diameter of the toner is 8.7 μm, the number average particle diameter is 8.2 μm, d
V / dn = 1.06. The maximum particle size in the particle size distribution was 9.8 μm.

Toner Production Example 2 n-Dodecyl mercaptan 0.1 in Toner Production Example 1.
The same operation as in toner production example 1 was performed except that 35 parts was changed to 0.15 parts, and the volume average particle diameter was 5.2 μm, the number average particle diameter was 4.8 μm, dV / dn = 1.08, and the maximum particle diameter was 6. 1μ
m of negatively chargeable toner B was obtained. However, hydrophobic silica R9
The addition amount of 72 was changed from 0.3% in toner production example 1 to 0.8%.

Carrier Production Example n-Dodecyl mercaptan 0.1 in toner production example 1.
35 parts to 0.45 parts, divinylbenzene 1.0 parts
Parts, 1 part of t-butylacrylamidosulfonic acid was changed to 1 part of dimethylaminoethyl methacrylate, and the same operation as in the toner production example was carried out to obtain a volume average particle diameter of 10.8 μm,
A spherical resin particle slurry having a minimum particle size of 9.5 μm was obtained.
This was washed and dried in the same manner as in the toner production example without coloring to obtain a carrier A. The true specific gravity of carrier A is 1.2 g /
cm ³ (and dV / dn was 1.06).

[0027]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The parts and percentages shown below are based on weight.

Example 1 80.0 parts of glass beads having a volume average particle diameter of 32.1 μm and a minimum particle diameter of 18.3 μm and 20 parts of toner A were mixed for 10 minutes by a ball mill to obtain a developer A of the present invention. The true specific gravity of the glass beads was 2.3 g / cm ³ . Table 1 shows the results of particle size measurement, image evaluation, and endurance test after developer A was placed in a small developing device similar to the one-component developing device shown in FIG. After passing through the toner layer thickness regulating member, no passage of the carrier was observed, no afterimage or background stain was observed, and A4 showed sufficient durability of 100,000 sheets, but the image density was slightly low. The volume and weight of the developer were clearly smaller and lighter than the two-component developer using a conventional magnetic carrier. In the developing device shown in FIG. 1, the toner layer after passing through the toner layer thickness regulating member was substantially a single layer.

Example 2 Table 1 shows the results of the same evaluation as in Example 1 performed by a developing apparatus using the same developer as in Example 1 and using a developer carrier having a surface layer made of silicone rubber. After passing through the toner layer thickness regulating member, no passage of the carrier is observed, no afterimage or background stain occurs, the image density is sufficient, and the durability is A4.
A 100,000-sheet test was sufficient. In this developing device, the toner layer after passing through the toner layer thickness regulating member was a multilayer of 4 to 5 layers.

Example 3 The surface layer of the developer carrying member in the developing device of Example 2 was made of silicon rubber. This was changed to silicon rubber containing aminosilane, and the toner was made positively negatively charged. Except for the above, the same evaluation was performed using the same developer as in Example 2, and the results are shown in Table 1. Although the results were almost the same as those in Example 2, the sharpness of the image was superior to that in Example 2, and the change in image quality in the durability test tended to be small.

Example 4 30 parts of toner B of Toner Production Example 2 and 70 parts of Carrier A of Carrier Production Example 1 were mixed for 10 minutes by a ball mill to obtain a developer B of the present invention. Table 1 shows the results of the same evaluation performed with the same developing device as in Example 3. No passage of the carrier was observed after passing through the toner layer thickness regulating member, and excellent image quality was exhibited as in Example 3. A4 20 in the durability test
The image quality was the same as the initial image quality even after copying many sheets, indicating that the reliability was very high. The amount of the developer was smaller and lighter than that of Example 3.

Comparative Example 1 Table 1 shows the results of the same evaluation as in Example 3 in which only the toner was put into the developing device without using a carrier in Example 3. When a document in which the first rotation of the developer carrying member was a character and the second rotation was a black solid was copied, an afterimage in which the image density was reduced corresponding to the preceding character portion occurred in the black solid portion. No background stain was observed on the image, but toner adhered to the background on the electrostatic latent image carrier, and the consumption of toner was larger than that in Example 3. In the durability test, thickening of letters and increase of background stain were recognized, and the test was stopped when A420,000 sheets were printed.

Comparative Example 2 The carrier had a volume average particle size of 25.3 μm and a minimum particle size of 10.
The same evaluation as in Example 3 was performed except that glass beads of 2 μm were used. Minimum particle size of carrier / Maximum particle size of toner =
1.04, indicating that the carrier was present after passing through the toner layer thickness regulating member, and that the carrier with the toner was adhered to the end of the character or line portion of the image. The durability test was not performed because the phenomenon of the carrier was observed.

COMPARATIVE EXAMPLE 3 The toner had a volume average particle size of 8.5 μm and dV / dn = 1.4.
8, a negatively chargeable pulverized toner having a maximum particle size of 17.9 μm, and a carrier having a volume average particle size of 66.5 μm and a minimum particle size of 3
As a developer, 8.1 parts of glass beads were mixed with 10 parts of the toner and 90 parts of the carrier in a ball mill for 10 minutes to obtain a developer, which was evaluated in the same manner as in Example 3. The results are shown in Table 1. The density of the initial image was slightly low, and the density tended to increase with the number of running images. Although the developer is lighter than the one using the conventional magnetic carrier, the amount of the developer is slightly reduced.

Comparative Example 4 The carrier had a volume average diameter of 34.8 μm and a minimum particle diameter of 17.9.
A developer was prepared and evaluated in the same manner as in Example 3 except that a ferrite carrier coated with a silicon resin having a specific gravity of 5.1 g / cm ^{3 and} a specific gravity of 5.1 μm was used. The results are shown in Table 1. Although the initial image was good, background stains occurred along with the running, and the background stains exceeded the permissible limit at 20,000 sheets.

[0036]

[Table 1]

[0037]

The effects of the present invention described above will be described below in relation to the configuration. 1. By using a carrier which does not contain a magnetic material capable of being charged to the opposite polarity to the toner in the developer according to claim 1, the toner can be charged more sufficiently and more stably than a one-component developer. No) A good image can be obtained, the weight can be reduced as compared with a two-component developer using a magnetic carrier, and the toner spent is reduced, so that the durability is improved. Further, the surface area of the carrier is increased by reducing the volume average particle diameter of the carrier to 5 times or less of the volume average particle diameter of the toner, so that the amount of the carrier to be used can be reduced. can do. In addition, the minimum particle size in the particle size distribution of the carrier is defined as 1.75 times the maximum particle size of the toner.
By making the ratio 5 times or more, in the developing device according to the second aspect, it becomes possible to form a thin layer substantially composed of only toner on the developer carrier after passing through the toner layer thickness regulating member.

2. 2. The developer according to claim 1, wherein the ratio dV / dn between the volume average particle diameter dV of the toner and the number average particle diameter dn is 1
By narrowing the particle size distribution to ≦ dV / dn ≦ 1.2, the minimum particle size of the carrier is not more than 5 times the average particle size of the toner, while the volume average particle size of the carrier is 5 times or less of the average particle size of the toner. It is possible to increase the number by five times or more. 3. A developing device including at least a developer carrier and a toner layer thickness regulating member and an electrostatic latent image carrier provided in contact with the developer carrier has the same configuration as a normal one-component developing device, It is lightweight and compact, and the presence of the toner layer thickness regulating member can remove the carrier from the developer of claim 1 to form a thin layer substantially composed of only toner on the developer carrier.

4. When a toner layer formed after passing through the toner layer thickness regulating member is to be formed into a multi-layer and uniform and sufficient image density is to be obtained, it is difficult for a conventional one-component developer to sufficiently charge the toner, resulting in an afterimage or a ground. Although an abnormal image such as a stain is likely to occur, the developer and the developing method of the present invention show more effective effects. 5. In the developing method of the present invention, the surface of the developer carrier and / or the surface of the toner layer thickness regulating agent can be charged to the opposite charge polarity to the toner of claim 1, that is, the same charge polarity as the carrier of claim 1, Further, since a sufficient charge can be stably applied to the toner, the image quality and the durability are excellent. 6. The true specific gravity of the carrier in the developer of the present invention is 1.5
With the following, higher durability can be achieved by weight reduction and prevention of spent.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an example of an apparatus suitable for carrying out the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic latent image carrier 2 developer carrier 3 toner layer thickness regulating member 4 developer supply member 5 developer stirring device 6 developer 7 developer holder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-70885 (JP, A) JP-A-4-177260 (JP, A) JP-A-5-27477 (JP, A) 237105 (JP, A) JP-A-47-13952 (JP, A) JP-A-1-101560 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 G03G 9 /Ten

Claims (4)

(57) [Claims] At least a binder resin and a colorant are contained,
Contains no magnetic material, and has a volume average particle diameter dV and a number average particle diameter d
a toner having a narrow particle size distribution having a ratio dV / dn of 1 ≦ dV / dn ≦ 1.2, and a carrier containing no magnetic material capable of being charged to the opposite charging polarity to the toner.
The volume average particle size of the carrier is 5 times or less the volume average particle size of the toner, and the minimum particle size in the particle size distribution is 1.5 times or more the maximum particle size of the toner. A non-magnetic two-component developer. 2. A developer carrying member, a toner layer thickness regulating member provided in contact with the developer carrying member, and an electrostatic latent image carrier provided in contact with or not in contact with the developer carrying member. A non-magnetic two-component developer according to claim 1 is carried on the developer carrying member by using a developing device comprising: a toner layer thickness regulating member; A developing method comprising forming a thin layer and adsorbing toner on the electrostatic latent image by electrostatic action. 3. The toner of claim 1, wherein at least one of the surface of the developer carrying member and the surface of the layer thickness regulating member can be charged to the same charge polarity as the carrier of claim 1. Item 3. The developing method according to Item 2. 4. The developing method according to claim 1, wherein the true specific gravity of the carrier is 1.5 g / cm ³ or less.