JP2003098824A - Development apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for forming images, which can inexpensively output stable image density in small size, without contamination on developer regulating members and a developer holder, and to provide a developer used for the method and the apparatus. SOLUTION: A development apparatus is provided with the first regulating member 17 for regulating a quantity of the developer held and carried by the developer holder 15 and a developer accommodating part 16a for accommodating the developer scraped by the first regulating member. The developer accommodating part has a second regulating member 23, disposed on the upstream side in the carrying direction of the developer in the developer holder 15 from the first regulating member 17. A gap C in between the second regulating member and the developer holder is set, so as to regulate the passage of an increment of the developer, when the concentration of toner of the developer in the developer holder 15 increases and the thickness of a layer of the developer increases. Electric field is formed between the first regulating member 17 and the developer holder 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method / apparatus using an electrophotographic method such as a copying machine, a printer and a facsimile, an electrostatic printing method and the like, and a developer used therefor.

[0002]

2. Description of the Related Art The electrophotographic method generally utilizes a photoconductive material to form an electrical latent image on an electrostatic latent image carrier by various means, and then develops the latent image with toner. Then, after the toner is transferred to paper or the like, if necessary, it is fixed by heating or solvent vapor to obtain a copy image or a print image. As a means for developing an electrostatic latent image formed on an electrostatic latent image carrier such as a photoconductor, a method using a liquid developer (wet development method) and a method in which a colorant is dispersed in a binder resin are used. Or a method using a one-component or two-component dry developer in which the toner is mixed with a carrier (dry development method). Although each of these methods has advantages and disadvantages, at present, the dry development method is widely used. Among these methods, the two-component developing method is relatively widespread, centering on medium- to high-speed copying machines and printers, because it can achieve relatively high speed and long life compared to the single-component developing method. is doing.

In recent years, there has been a strong demand for higher definition and higher resolution of copied or printed images. In order to obtain such a high-definition, high-resolution image, Japanese Patent Laid-Open No. 1-1122
53, JP-A-2-284158, JP-A-7
In JP-A-295283, the average particle size is small and 5
A developer having a toner particle content of less than or equal to μm and its distribution defined has been proposed. Here, toner particles of 5 μm or less are essential components for forming a high-definition, high-resolution image, and when toner of this particle size is smoothly supplied during development of a latent image, it is true to the latent image. That is, it is said that an image with excellent reproducibility that does not protrude from the latent image can be obtained.
On the other hand, the edge effect phenomenon in which the density of the central portion of the image is lower than that of the edge portion is as follows:
Although it appears remarkably, it is said that this problem can be solved by defining the number% of toner particles having an intermediate particle diameter of 5 μm or more.

As described above, the toner of recent years is 5 μm.
The following toner particles tend to increase,
There are many issues (problems) associated with it. For example, in the largest area, the developer regulating member is contaminated, and the developer carrying member is contaminated. As described above, if the number of toner particles having a particle size distribution of 5 μm or less is increased, the number of ultrafine particles having a particle size of 2 μm or less will inevitably increase. If the above-mentioned ultrafine particles of 2 μm or less are obtained, the surface area per unit weight becomes too large, and the toner fluidity is remarkably lowered. Then, the abnormal situation in which the above-mentioned ultrafine particles of 2 μm or less are completely adhered (fixed) on the surface of the developer regulating member and the surface of the developer carrier and are not collected again on the surface of the carrier particles (in this case, it is necessary to replace the developing device). Will occur). Further, in the case of the developing device using the magnetic toner, since the magnetic bias is formed between the magnetic toner and the inside of the developer carrier,
The magnetic toner once attached to the developer carrying member may be more troublesome to peel off than the non-magnetic toner.

The above-mentioned contamination of the developer regulating member and the contamination of the developer carrying member are very serious problems. First, when the developer regulating member is contaminated with toner, the effect of regulating the amount of developer varies greatly depending on the degree of contamination, that is, the amount of developer conveyed to the developing area changes with time. Therefore, the fluctuation of the image density becomes large depending on the usage of the developing device. On the other hand, when the developer carrying member is contaminated, the developing electric field effect in the developing area changes depending on the degree of contamination, which causes a problem that the image density becomes unstable. In the worst case, depending on how the surface of the developer bearing member is soiled, an undesired phenomenon occurs in which an image density deviation occurs in one output image.

[0006]

SUMMARY OF THE INVENTION Therefore, in view of the above-mentioned conventional technique, an object of the present invention is to prevent contamination of a developer regulating member in a developing device using a magnetic toner having a large proportion of toner particles of 5 μm or less. Another object of the present invention is to provide a developing device, and another object is to provide a developing device in which the developer carrier is not contaminated. Another object of the present invention is to provide a stable image density regardless of the use condition of the developing device. Another object is to provide a small and inexpensive image forming method / apparatus that does not require a toner replenishing mechanism and a toner concentration sensor, and a developer used therefor. is there.

[0007]

Means for Solving the Problems The above-mentioned problem is (1) of the present invention, "having a magnetic field generating means inside and comprising at least a binder resin, a magnetic toner made of a magnetic substance, and a magnetic carrier made of at least a magnetic substance. A developer carrying member carrying and carrying a two-component developer, and a first restricting member for restricting the amount of the developer carried and carried by the developer carrying member,
The developing device further includes: a developer accommodating portion that accommodates the developer scraped off by the first regulating member; and a toner accommodating portion that is adjacent to the developer accommodating portion and that supplies toner to the developer carrier. A developing device for changing a contact state between the developer and the toner according to a change in toner concentration of the developer on the developer carrying member to change a toner taking-in state of the developer on the developer carrying member. , The developer container is
A second restricting member arranged upstream of the first restricting member in the conveying direction of the developer on the developer carrying member;
The regulating member of the developer carrying member is provided to regulate the passage of the increased amount of the developer when the toner concentration of the developer on the developer carrying member increases and the layer thickness of the developer increases. And a gap is set, and an electric field is formed between the first restricting member and the developer carrying member ", (2)" the first restricting member and the developing device. The electric field formed between the developer carrier and the developer carrier is an alternating electric field, and the developing device described in the above item (1), (3) "The magnetic carrier contains at least a silicone resin as a main component. The developing device according to item (1) or (2) above, which comprises a coating layer, and (4) "silica oil-treated silica fine powder is added to the magnetic toner. In the above item (1) or (2),
Item 5. The developing device according to item 5), wherein the toner concentration sensor is not used.
The developing device according to any one of items 1 to 6, and (6) "the developing device according to any one of the items (1) to (5), which does not use an image density sensor". To be achieved.

According to the study by the present inventors, a magnetic field generating means is provided inside and a two-component developer comprising a magnetic toner composed of at least a binder resin and a magnetic material and a magnetic carrier composed of at least a magnetic material is carried. And a developer carrier to be conveyed,
A first restricting member that restricts the amount of the developer carried and conveyed by the developer carrier, and a developer accommodating portion that accommodates the developer scraped off by the first restricting member,
A toner accommodating portion adjacent to the developer accommodating portion for supplying toner to the developer bearing member, wherein the toner concentration of the developer on the developer bearing member changes, and thereby the developer and the toner are separated from each other. A developing device for changing a contact state to change a toner taking-in state of a developer on the developer carrier, wherein the developer accommodating portion is arranged on the developer carrier more than a first regulating member. It has a second regulating member arranged on the upstream side in the developer conveying direction. The second regulating member increases the toner concentration of the developer on the developer carrying member, and increases the layer thickness of the developer. In the developing device in which a gap between the developer carrier and the developer carrier is set so as to regulate the passage of the increased amount of the developer when the number of the developer increases, between the first regulator member and the developer carrier. It is important that the formation of an electric field in the core plays an important role in solving the above-mentioned problems. It was heading.

For example, if a developing bias is applied to the developer carrying member at the timing of development by grounding the developer restricting member, a developing bias of toner from the developer carrying member to the developer restricting member is generated. As a result, the ultrafine particles of 2 μm or less attached to the surface of the developer carrying member are developed on the developer regulating member, and the toner contamination on the surface of the developer carrying member is eliminated. Further, for example, when a bias having a polarity opposite to the polarity of the toner is applied to the developer carrying member at a timing other than development, a developing bias of the toner from the developer regulating member to the developer carrying member is generated and the developer regulating member is The adhered ultra fine particles of 2 μm or less come to be developed on the developer carrying member, and the toner contamination of the developer regulating member is eliminated. It is possible to eliminate both the developer regulating member and the developer carrier from contamination by adjusting the time and the potential for applying the bias of the opposite polarity to the toner applied to the developer carrier at the timing other than the above-mentioned development. We were able to confirm what we could do by experiments.

Furthermore, by making the electric field formed between the developer regulating member and the developer carrying member an alternating electric field, both the developer regulating member and the developer carrying member can be more efficiently eliminated from contamination. It was possible to confirm by experiment that things could be done. More specifically, the developer regulating member is connected to an AC power source to form an alternating electric field between the developer regulating member and the developer carrying member. The following ultra-fine particles will be periodically developed on the developer regulating member or the developer carrying member, and as a result, both the developer regulating member and the developer carrying member can be more efficiently eliminated from contamination. I was able to.

The inventors have found that the magnetic carrier comprising a coating layer containing at least a silicone resin as a main component accelerates the elimination of toner contamination on the surface of the developer regulating member and the surface of the developer carrying member. Although the exact reason why such an effect is exhibited is not clear, it is considered that the hard coating of the silicone-coated carrier has a very high polishing effect and the ultrafine particles having a strong adhesive force of 2 μm or less form the surface of the silicone-coated carrier. Depending on the polishing power,
It is presumed that it was easily torn off from the attached object.

Furthermore, the present inventors have found that the surface of the developer controlling member and the surface of the developer carrying member can be always kept fresh by adding silica fine powder treated with silicone oil to the magnetic toner of the present invention. I was able to find it. This means that when the silicone oil present on the surface of the silica fine powder migrates to the developer carrier or the developer regulating member, ultrafine particles of 2 μm or less easily attach due to the releasing effect of the silicone oil. It is thought that it was possible to maintain a fresh state at all times because it became difficult.

The fluidity-imparting agents used in the present invention include Si, Ti, Al, Mg, Ca, Sr, Ba and I.
n, Ga, Ni, Mn, W, Fe, Co, Zn, Cr,
Examples thereof include oxides and complex oxides such as Mo, Cu, Ag, V, and Zr, and these may be used alone or in combination of two or more. Of these, fine particles of silicon dioxide (silica), titanium dioxide (titania), and alumina are preferably used. Of these, those having a primary particle diameter of 0.1 μm or less are preferable. Further, it is effective to perform a surface modification treatment with a hydrophobic treatment agent or the like. The following are typical examples of the hydrophobizing agent.

Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyl. Trichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane,
Vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl-trichlorosilane,
Decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane,
Dipentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl-dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4
-T-butylphenyl) -octyl-dichlorosilane,
Dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di-3,3-dimethylbenzyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane, dioctyl-methyl-chlorosilane, Octyl-dimethyl-chlorosilane, (4-t-propylphenyl)
-Diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane, hexatolyldisilazane and the like. In addition to these, titanate-based coupling agents and aluminum-based coupling agents can also be used.

(Silicone oil) Examples of the silicone oil used in the present invention include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil and polyether-modified silicone oil. Silicone oil, alcohol-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, α-methyl Styrene-modified silicone oil can be used.

Of these fluidity imparting agents, 0.05 μm
The combined use of the following hydrophobic silica fine particles and hydrophobic titanium oxide fine particles having an average particle diameter of 0.05 μm or less was most effective for environmental stability and image density stability. The fluidity-imparting agent used in the present invention is 0.1 to 2 with respect to the toner.
It is preferably used in weight percent. If the amount is less than 0.1% by weight, the effect of improving toner aggregation is poor, and the amount is 2% by weight.
If it exceeds the range, problems such as toner scattering between fine lines, contamination inside the machine, scratches and abrasion of the photoconductor tend to occur. The key point of the present invention is that a predetermined fluidity can be secured even with a small amount of addition, and a high resolution image quality can be maintained even for a large number of copies and prints for a long period of time. This effect is obtained with a toner amount of 5 μm or less. It was obviously more effective than the case where the fluidity-imparting agent was added in a large amount.

Further, other additives such as polytetrafluoroethylene-based fluororesin powder, zinc stearate powder, and polyvinylidene fluoride powder can be added to the developer of the present invention as long as they do not have a substantial adverse effect. Lubricant powder; or abrasive such as cerium oxide powder, silicon carbide powder, strontium titanate powder; or conductivity-imparting agent such as carbon black powder, zinc oxide powder, tin oxide powder; , And black fine particles can be used in a small amount as a developing property improver.

As the binder resin for toner of the present invention, conventionally known ones can be widely used. Examples of the binder resin used in the present invention include polystyrene and poly-p.
-Homopolymers of styrene such as chlorostyrene and polyvinyltoluene and substitution products thereof; styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers Coal, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene vinyl methyl ketone copolymer Styrene-based copolymers such as polymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers; acrylic resins, methacrylic resins, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene Polyester resins, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin,
Terpene resin, phenol resin, natural resin modified phenol resin, natural resin modified maleic acid resin, polyurethane,
Examples thereof include polyamide resin, furan resin, epoxy resin, coumaroindene resin, silicone resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, and the like, which may be used alone or in combination. In particular, styrene-based copolymers and polyester resins are preferable in terms of development characteristics, fixability and the like.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, A monocarboxylic acid having a double bond such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; maleic acid, butyl maleate, malein Dicarboxylic acids having a double bond such as methyl acidate and dimethyl maleate and substituted compounds thereof; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene such as ethylene, propylene and butylene System olefins; vinyl methyl ketone, vinyl ketones such as vinyl hexyl ketone;
Examples thereof include vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether, and these vinyl monomers may be used alone or in combination of two or more.

The polyester resin can be produced by a known synthesis method using an alcohol component and an acid component as raw materials.
As the alcohol component, polyethylene glycol, diethylene glycol, triethylene glycol, 1,2
Diols such as propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butene diol,
Etherified bisphenols such as 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropyleneized bisphenol A, which are saturated or unsaturated with 3 to 22 carbon atoms. Divalent alcohol units substituted with saturated hydrocarbon groups, other divalent alcohol units, sorbitol, 1, 2, 3,
6-hexanetetrol, 1,4-salbitan, pentaesthritol, dipentaesthritol, tripentaesthritol, sucrose, 1,2,4-butanetriol, 1,
Trivalent of 2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. The above-mentioned other polyhydric alcohol monomers and the like can be mentioned.

As the acid component, palmitic acid, stearic acid, monocarboxylic acids such as oleic acid, maleic acid,
Fumaric acid, mesaconic acid, citraconic acid, itaconic acid,
Glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, and divalent ones obtained by substituting them with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms. Organic acid monomers, anhydrides of these acids, dimers of lower alkyl ester trinoleic acid, other divalent organic acid monomers, 1,2,4-benzenetricarboxylic acid, 1,2,5
-Benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- Examples include octane tetracarboxylic acid embol trimer acid, trivalent or higher polyvalent carboxylic acid monomers such as anhydrides of these acids, and the like.

The following are used as the pigment used in the present invention. Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides. As yellow pigments, cadmium yellow, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S,
Examples include Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, and Tartrazine Lake. Examples of orange pigments include molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK. Examples of red pigments include red iron oxide, cadmium red, permanent red 4R, resole red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake,
Brilliant Carmine 3B is mentioned. Examples of purple pigments include fast violet B and methyl violet lake. Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated compound, fast sky blue, and indanthrene blue BC. Examples of green pigments include chrome green, chromium oxide, pigment green B, and malachite green lake. These can use 1 type (s) or 2 or more types.

Further, a release agent may be internally added to the toner of the present invention in order to prevent offset during fixing. As the release agent, natural wax such as candelilla wax, carnauba wax, rice wax, montan wax, paraffin wax, sazol wax, low molecular weight polyethylene, low molecular weight polypropylene,
There are alkyl phosphates and the like. These are selected depending on the binder resin and the surface material of the fixing roller. The melting point of these release agents is preferably 65 to 90 ° C.
If it is lower than this range, blocking during storage of the toner is likely to occur, and if it is higher than this range, offset is likely to occur in a region where the fixing roller temperature is low.

For the toner, it is preferable to use the charge control agent internally added to the toner particles or externally added to the toner particles. The charge control agent makes it possible to control the optimum charge amount according to the developing system. In particular, the present invention is effective when used in the developing method in which the toner concentration is not controlled by using the charge control agent.

The polarity controlling agent used in the toner may be a conventionally known one, and the positive polarity controlling agent may be a modified product of nigrosine and a fatty acid metal salt; tributylbenzylammonium-1-hydroxy-4-naphthosulfonic acid. Salt, quaternary ammonium salt such as tetrabutylammonium tetrafluoroborate; diorganotin oxide such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borate such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate alone Alternatively, two or more kinds can be used in combination. Among these, polar control agents such as nigrosine compounds and organic quaternary ammonium salts are particularly preferably used. As the negative polarity controlling agent, for example, an organic metal compound or a chelate compound is effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, chromium 3,5-ditertiary-butylsalicylate, zirconium 3,5-ditertiary-butylsalicylate, and the like, particularly acetylacetone metal complex, monoazo metal complex, naphthoate. An acid or salicylic acid type metal complex or salt is preferable, and a salicylic acid type metal complex, a monoazo metal complex or a salicylic acid type metal salt is particularly preferable.
The polarity control agent is preferably used in the form of fine particles, and specifically, a number average particle diameter of 3 μm or less is preferable. The amount of the polarity control agent used in the toner is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method including the dispersion method, and is uniquely limited. However, it is preferably in the range of 0.1 to 2 parts by weight with respect to 100 parts by weight of the binder,
It is preferably used in an amount of 0.2 to 1 part by weight. If the amount is less than 0.1 parts by weight, the amount of charge of the toner is insufficient, which is not practical. On the other hand, if the amount exceeds 2 parts by weight, the charge amount of the toner is too large and the electrostatic attraction with the carrier is increased, so that the fluidity of the developer is lowered and the image density is lowered.

The toner of the present invention is preferably used as a magnetic toner, and magnetic materials used in the magnetic toner include iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, or these. Metals aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth,
Cadmium, calcium, manganese, selenium, titanium,
Examples thereof include alloys of metals such as tungsten and vanadium and mixtures thereof. Among these, magnetite is particularly useful. This magnetite is manufactured by a known manufacturing method. For example, an iron sulfate aqueous solution is neutralized with an alkaline aqueous solution to obtain iron hydroxide. After that, the marine ferrous metal suspension whose pH is adjusted to 10 or more is oxidized with a gas containing oxygen to obtain a magnetite slurry. Next, the slurry is washed with water, filtered, thought and crushed to obtain magnetite particles.
These ferromagnetic materials have an average particle size of 0.01 to 1 μm, preferably 0.1 to 0.5 μm. The amount contained in the magnetic toner is 5 to 80 wt% with respect to the toner,
Particularly preferably, it is 10 to 60 wt% with respect to the toner. The magnetization of the magnetic toner used in the present invention in a magnetic field of 5 k Oersted is 10 to 25 [emu / g], preferably 15 to 20 [emu / g]. The magnetic substance of the magnetic toner used in the present invention has a FeO content of 5 to 5
It is preferable that the content is 0 wt%, preferably 10 to 30 wt%, and the specific surface area is 1 to 60 m ² / g, preferably 3 to 20 m ₂ / g.

As an example of the method for producing the two-component developer according to the present invention, first, the above-mentioned binder resin, pigment or dye as a colorant, charge control agent, lubricant, other additives and the like are added to a Henschel mixer. After thoroughly mixing with a mixer such as, a batch type two-roll, Banbury mixer or continuous type twin-screw extruder, for example, KTK twin-screw extruder manufactured by Kobe Steel, TEM twin-screw manufactured by Toshiba Machine Co., Ltd. Extruder, K
CK twin-screw extruder, Ikegai Iron Works PCM-type twin-screw extruder, Kurimoto Iron Works KEX-type twin-screw extruder, continuous single-screw kneader, for example Buss Co-kneader The constituent materials are well kneaded using the above heat kneader, cooled, and then coarsely crushed using a hammer mill or the like. In the case of color toner,
For the purpose of improving the dispersion of the pigment, it is general to use a masterbatch obtained by previously melt-kneading a part of the binder resin and the pigment as a colorant. Further, these coarsely pulverized products are finely pulverized using a fine pulverizer using a jet stream or a mechanical pulverizer alone or in combination. Next, the obtained fine powder particles are classified into a predetermined particle size by a classifier using a swirling airflow or a classifier using the Coanda effect. Among them, a classifier utilizing the Coanda effect is preferably used to obtain the toner having the particle size distribution of the present invention. Further, the fluidity-imparting agent is thoroughly mixed with a mixer such as a Henschel mixer and passed through a sieve of 250 mesh or more to remove coarse particles and agglomerated particles.

As the magnetic carrier used in the present invention, conventionally known ones can be used. For example, magnetic particles such as iron powder, ferrite powder, nickel powder, magnetite powder or the surface of these magnetic particles is treated with a resin. Or magnetic particles dispersed resin particles in which magnetic particles are dispersed in a resin. The average particle size of these magnetic carriers is preferably 30 to 70 μm.

Examples of the resin forming the coat layer include polyethylene, polypropylene, chlorinated polyethylene,
Polyolefin resins such as chlorosulfonated polyethylene; polystyrene, acrylic (for example, polymethylmethacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral,
Polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinylidene, and other polyvinyl and vinylidene resins; vinyl chloride-vinyl acetate copolymers, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Polyamide; Polyester; Polyurethane; Polycarbonate; Amino resin such as urea-formaldehyde resin; Epoxy resin and silicone resin. Among these, the one having a silicone resin layer on the surface of magnetic particles or the one having a silicone resin layer containing carbon black has the best spent resistance.

The silicone resin of the present invention may be any conventionally known silicone resin, such as straight silicones consisting only of organosiloxane bonds represented by the following formula and alkyds, polyesters, epoxies, urethanes and the like. Examples include modified silicone resins.

[0031]

[Chemical 1] In the above formula, R ₁ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, R ₂ and R ₃ are hydrogen groups, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a phenoxy group,
An alkenyl group having 2 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a hydroxy group, a carboxyl group,
It is an ethylene oxide group, a glycidyl group or a group represented by the following formula.

[0032]

[Chemical 2] In the above formula, R ₄ and R ₅ are a hydroxy group, a carboxyl group,
An alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a phenyl group, a phenoxy group, k, l , M, n, o, p are integers of 1 or more. In the above, each substituent is an unsubstituted one, for example, an amino group, a hydroxy group, a carboxyl group, a mercapto group,
It may have a substituent such as an alkyl group, a phenyl group, an ethylene oxide group, a glycidyl group and a halogen atom.

By including carbon black in the coat layer, desired electric resistance of the carrier can be obtained. As the carbon black used in the present invention, all carbon blacks such as furnace black, acetylene black and channel black can be used. Among these, in particular, by using a mixture of furnace black and acetylene black, it is possible to effectively adjust the conductivity with a small amount of addition and to obtain a carrier having excellent abrasion resistance of the coat layer. These carbon blacks preferably have a particle size of about 0.01 to 10 μm, and are preferably added in an amount of 2 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the coating resin.

Further, a silane coupling agent, a titanium coupling agent or the like may be added to the carrier coating layer for the purpose of improving the adhesiveness with the core particles and the dispersibility of the conductivity-imparting agent. Good. The silane coupling agent used in the present invention is a compound represented by the following general formula.

[0035]

## STR00003 ## YRSiX _{3 wherein} X is a hydrolyzable group bonded to a silicon atom, and examples thereof include a chloro group, an alkoxy group, an acetoxy group, an alkylamino group and a propenoxy group. Y is an organic functional group that reacts with the organic matrix, and examples thereof include a vinyl group, a methacrylic group, an epoxy group, a glycidoxy group, an amino group, and a mercapto group. R is an alkyl group having 1 to 20 carbon atoms or an alkylene group. Among this silane coupling agent,
In particular, an aminosilane coupling agent having an amino group in Y is preferable for obtaining a toner having a negative charging property, and an epoxysilane coupling agent having an epoxy group in Y is preferable for obtaining a toner having a positive charging property.

The method for forming the coat layer is the same as the conventional method.
The coating layer forming liquid may be applied to the surface of the carrier core particles by a method such as a spraying method or a dipping method. The thickness of the coat layer is 0.
1 to 1 μm is preferable.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of a main part of a developing device of an image forming apparatus showing an embodiment of the present invention. The developing device (13) disposed on the side of the photoconductor drum (1), which is a latent image carrier, includes a support case (14), a developing sleeve (15) as a developer carrier, and a developer accommodating member ( 1
6), mainly composed of a first doctor blade (17) as a developer regulating member. The doctor blade (17) may be connected to an AC power source (not shown) or may be grounded, depending on the purpose of the present invention.

The support case (14) having an opening on the side of the photosensitive drum (1) forms a toner hopper (19) as a toner storage portion for storing the toner (18) therein. A developer accommodating portion (16) accommodating a developer (22) composed of the toner (18) and a carrier that is magnetic particles is provided near the photosensitive drum (1) side of the toner hopper (19).
A developer accommodating member (16) forming a) is provided integrally with the support case (14). Further, a protrusion (14a) having a facing surface (14b) is formed on the support case (14) located below the developer accommodating member (16), and the protruding portion (14a) is formed below the developer accommodating member (16). The space between the facing surface (14b) forms a toner supply opening (20) for supplying the toner (18).

Inside the toner hopper (19), a toner agitator (21) as a toner supplying means which is rotated by a driving means (not shown) is arranged. The toner agitator (21) sends the toner (18) in the toner hopper (19) toward the toner supply opening (20) while stirring. Also, toner hopper (19)
On the side facing the photoconductor drum (1), a toner end detection means (14c) is provided for detecting when the amount of toner (18) in the toner hopper (19) is low. There is.

Photoreceptor drum (1) and toner hopper (1
A developing sleeve (15) is arranged in a space between the developing sleeve (9). The developing sleeve (15), which is rotationally driven in the direction of the arrow in the figure by a driving means (not shown), is arranged inside the developing sleeve (15) so that the relative position of the developing sleeve (15) does not change. have. A developing bias is applied to the developing sleeve (15) by a power source (not shown), and a voltage is applied to the developing sleeve (15) for purposes other than the development according to the purpose of the present invention. The first doctor blade (1) is provided on the side of the developer accommodating member (16) facing the side attached to the support case (14).
7) is integrally attached. The first doctor blade (17) is arranged in a state where a certain gap is maintained between the tip of the first doctor blade (17) and the outer peripheral surface of the developing sleeve (15).

A second doctor blade (23) as a regulating member is provided at a portion of the developer accommodating member (16) located near the toner supply opening (20).
The second doctor blade (23) has a layer of the developer (22) formed on the surface of the developing sleeve (15) so that its free end maintains a constant gap with respect to the outer peripheral surface of the developing sleeve (15). The base end is integrally attached to the developer accommodating member (16) so that the flow is blocked, that is, the free end faces the center of the developing sleeve (15). The developer accommodating portion (16a) is configured to have a sufficient space for circulating and moving the developer (22) within the range where the magnetic force of the developing sleeve (15) reaches.

The facing surface (14b) is formed over a predetermined length so as to incline downward from the toner hopper (19) side toward the developing sleeve (15) side. As a result, when vibration, uneven magnetic force distribution of a magnet (not shown) provided inside the developing sleeve (15), or partial increase in toner concentration in the developer (22) occur, the second doctor blade ( 23) and developing sleeve (1
Even if the carrier in the developer accommodating portion (16a) falls from between the peripheral surface of (5) and the peripheral surface of
It is received by b), moves to the developing sleeve (15) side, is magnetically attached to the developing sleeve (15) by magnetic force, and is supplied again into the developer accommodating portion (16a). As a result, it is possible to prevent a decrease in the amount of carriers in the developer accommodating portion (16a), and it is possible to prevent uneven image density in the axial direction of the developing sleeve (15) during image formation. The inclination angle (α) of the facing surface (14b) is about 5 °,
Further, the predetermined length (l) is preferably 2 to 20.
mm, and more preferably about 3 to 10 mm.

With the above structure, the toner hopper (19)
The toner (18) sent from the inside of the printer by the toner agitator (21) passes through the toner supply opening (20) and the developer (22) carried on the developing sleeve (15).
Is supplied to the developer storage unit (16a). Then, the developer (22) in the developer accommodating portion (16a) is carried by the developing sleeve (15) and conveyed to a position facing the outer peripheral surface of the photosensitive drum (1), and only the toner (18) is conveyed. A toner image is formed on the photosensitive drum (1) by electrostatically coupling with the electrostatic latent image formed on the photosensitive drum (1).

Here, the behavior of the developer (22) at the time of forming the toner image will be described. When the starter composed of only the magnetic carrier (22a) is set in the developing device (13), the magnetic carrier (22a) is magnetically adhered to the surface of the developing sleeve (15) as shown in FIG. The parts (16a) are divided into those accommodated in the part (16a). The magnetic carrier (22) accommodated in the developer accommodating portion (16a)
With the rotation of the developing sleeve (15) in the direction of the arrow (a), a) is circulated in the direction of the arrow (b) at a moving speed of 1 mm / s or more due to the magnetic force from inside the developing sleeve (15). Then, the surface of the magnetic carrier (22a) magnetically attached to the surface of the developing sleeve (15) and the developer accommodating portion (16).
An interface (X) is formed at the boundary with the surface of the magnetic carrier (22a) moving in a).

Next, when the toner (18) is set in the toner hopper (19), the toner supply opening (20) is set.
The toner (18) is supplied to the magnetic carrier (22a) carried by the developing sleeve (15). Therefore, the developing sleeve (15) carries the developer (22) which is a mixture of the toner (18) and the magnetic carrier (22a).

In the developer accommodating portion (16a), due to the presence of the developer (22) contained, the developing sleeve (1
The developer (22) conveyed by 5) acts on the developer (22) to stop the conveyance. Then, when the toner (18) existing on the surface of the developer (22) carried on the developing sleeve (15) is conveyed to the interface (X), friction between the developers (22) near the interface (X). The force is reduced and the transporting force of the developer (22) near the interface (X) is reduced, which causes the developer (22) near the interface (X).
The transport amount of is reduced.

On the other hand, the developing sleeve (1
The developer (22) on the upstream side in the rotational direction of 5) has a developing sleeve (1) such as in the developer accommodating portion (16a).
The developer (22) conveyed by 5) does not act on the developer (22) conveyed to the confluence (Y) because the force for stopping the conveyance does not act on the developer (22). The balance of the amount of conveyance with the developer (22) to be generated is disturbed and a bump state of the developer (22) occurs, the position of the confluence point (Y) rises, and the developer (22) including the interface (X). ) Increases the layer thickness. Further, the layer thickness of the developer (22) that has passed through the first doctor blade (17) also gradually increases, and the increased developer (22) is scraped off by the second doctor blade (23).

When the developer (22) having passed through the first doctor blade (17) reaches a predetermined toner concentration, as shown in FIG. 4, the second doctor blade (23).
Increasing amount of developer scraped off by a layer (22)
Closes the toner supply opening (20), and in this state, the taking-in of the toner (18) is completed. At this time, since the toner concentration in the developer accommodating portion (16a) is increased, the bulk of the developer (22) is increased, and thus the space in the developer accommodating portion (16a) is narrowed, so that the developer is reduced. The moving speed at which (22) circulates in the direction of the arrow (b) in the figure also decreases.

In the layer of the developer (22) formed so as to close the toner supply opening (20), the developer (22) scraped off by the second doctor blade (23).
Is moved by a moving speed of 1 mm / s or more and received by the facing surface (14b) as indicated by an arrow (c), the facing surface (14b) forms an angle () toward the developing sleeve (15) side. Prevents the developer (22) from falling into the toner hopper (19) due to the movement of the layer of the developer (22) because it is inclined downward at α) and has a predetermined length (l). Since the amount of the developer (22) can be kept constant at all times, the toner supply can be constantly controlled to be constant.

The measuring method according to the present invention will be described below. The toner particle size distribution used in the present invention can be measured by various methods, but in the present invention, it was measured using a Coulter counter. That is, a Coulter counter TA-II type (manufactured by Coulter) is used as a measuring device, an interface (manufactured by Nikkaki) for outputting number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC) are connected, and the electrolyte is 1 Prepare a 1% aqueous NaCl solution using graded sodium chloride. As a measuring method, a surfactant, preferably 0.1 to 5 ml of an alkylbenzene sulfonate is added as a dispersant to 10 to 15 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. Perform dispersion processing for ~ 3 minutes. 100-200 ml of electrolytic aqueous solution was put into another beaker, the sample dispersion liquid was added thereto to a predetermined concentration, and the Coulter Counter TA-II type was used with an aperture of 100 μm as an aperture to measure 2 to The particle size distribution of 40 μm particles was measured and 2
The volume distribution and number distribution of particles of ˜40 μm were calculated, and the weight-based weight average particle diameter (D4: the median value of each channel was used as the representative value of the channels) determined from the volume distribution.

[0051]

EXAMPLES The present invention will be specifically described below with reference to examples. (Carrier production example) Carrier A prototype example Magnetite particles (trade name: SM-400, manufactured by Dowa Iron Powder Co., Ltd.) were used, and a coating machine (Okada Seiko Co., Ltd .: Spiracoater) was applied to a carrier core material having an average particle size of 50 μm. 100 parts by weight of the carrier core material was coated with the following composition, and baked at 170 ° C. for 30 minutes to obtain a carrier A. Resin * (Hitachi Metals HM-40) 3 parts by weight Curing agent (melamine-formalin) 0.1 parts by weight * 30% by weight of polyvinyl fluoride modified with a carboxyl group and 70% by weight of styrene-acrylic resin A mixture of

[0052] Dispersion b   Charge the following materials into a homomixer and keep the jacket temperature at 30-40 ° C. After stirring for 20 minutes, dispersion liquid b was obtained.   Silicone resin (Product name: SR2410, Toray Dow Corning Silicone 450)   Toluene 450 parts   Aminosilane (Product name: SH6020, Dow Corning Toray Silicone Co., Ltd. Made) 9 parts   Carbon black (Product name: Black Perls2000, CABOT CORPORATION)                                                             10 copies

Carrier B Prototype Example Magnetite particles (trade name: SM-400, manufactured by Dowa Iron Powder Co., Ltd.) were used, and a carrier core material having an average particle size of 50 μm was coated with a coating machine (Okada Seiko Co., Ltd .: Spiracoater). The carrier core material was coated with 18.4% by weight of the above dispersion liquid b, and further baked at 300 ° C. for 2 hours to obtain a carrier B coated with the above resin.

[0054]

[Table 1] An example of toner production is shown below.

(Toner Production Example) Toner 1 polyester resin 100 parts by weight 3,5-di-tertiary-butyl zirconium salicylate 1 part by weight magnetite fine particles 25 parts by weight polypropylene 5 parts by weight After mixing the mixture of the above formulation with a Henschel mixer, 1
After kneading with a kneading extruder set at 80 ° C,
After cooling and solidifying, this was roughly crushed with a cutter mill, then finely crushed with a mechanical crusher, and the finely crushed product obtained was 5 μm with a multi-division classifier utilizing the Coanda effect.
The following was classified into a particle size distribution of 65% by number to obtain base particles.
Further, 0.5 part by weight of untreated silica MOX170 (manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of the mother colored particles and mixed by a Henschel mixer to obtain a toner 1.

[0056]

[Table 2]

(Production Example of Silicone Oil Treated Silica) 5.0 parts by weight of polydimethylsiloxane (produced by Shin-Etsu Chemical Co., Ltd.) having a viscosity of 350 cs was dissolved in 100 parts by weight of toluene,
Untreated silica MOX170 (manufactured by Nippon Aerosil Co., Ltd.) 30
Parts by weight were dispersed therein by ultrasonic irradiation with stirring. After visually confirming that there were no aggregates, toluene was distilled off using a rotary evaporator. The obtained solid matter is set in a vacuum dryer at a set temperature of 50 ° C.
And dried to constant weight. Further, heat treatment was performed at 200 ° C. for 2 hours in a nitrogen stream in an electric furnace. The obtained powder was crushed by a jet mill and collected by a bag filter.

(Toner 2) Base particles 10 of Toner 1
0.5 part by weight of the silica treated with silicone oil was mixed with 0 part by weight with a Henschel mixer to obtain a toner 2.

(Comparative Example 1) 90 parts by weight of carrier A and 1:10 parts by weight of toner were mixed using a Turbula mixer to obtain a two-component developer I. The two-component developer I was set in the developing device shown in FIG. At this time, the doctor blade is in a floating state. Next, the developing device shown in FIG. 1 was incorporated into imagio MF200 manufactured by Ricoh Co., Ltd., and the durability was evaluated and the contamination state on the back of the doctor blade and the surface of the developing sleeve was confirmed after 100,000 sheets. The image density unevenness was also evaluated, and the results are shown in Table 3.

(Example 1) 90 parts by weight of carrier A and 1:10 parts by weight of toner were mixed using a Turbula mixer to obtain a two-component developer I. The two-component developer I was set in the developing device shown in FIG. At this time, the doctor blade has an external power supply (output: Vp _-p 1KV, f3KHz,
Sine wave) was connected. Next, the developing device shown in FIG. 1 was incorporated into imagio MF200 manufactured by Ricoh Co., Ltd., and the durability was evaluated and the contamination state on the back of the doctor blade and the surface of the developing sleeve was confirmed after 100,000 sheets. The image density unevenness was also evaluated, and the results are shown in Table 3.

(Example 2) 90 parts by weight of carrier B and 1:10 parts by weight of toner were mixed using a Turbula mixer to obtain a two-component developer II. The two-component developer II was set in the developing device shown in FIG. At this time, the doctor blade has an external power supply (output: Vp _-p 1KV, f3KHz,
Sine wave) was connected. Next, the developing device shown in FIG. 1 was incorporated into imagio MF200 manufactured by Ricoh Co., Ltd., and the durability was evaluated and the contamination state on the back of the doctor blade and the surface of the developing sleeve was confirmed after 100,000 sheets. The image density unevenness was also evaluated, and the results are shown in Table 3.

(Example 3) 90 parts by weight of carrier B and 2:10 parts by weight of toner were mixed using a Turbula mixer to obtain a two-component developer III. The two-component developer III was set in the developing device shown in FIG. At this time, the doctor blade has an external power source (output: Vp _-p 1KV, f 3KH
z, sine wave). Next, the developing device shown in FIG. 1 was incorporated into imagio MF200 manufactured by Ricoh Co., Ltd., and the durability was evaluated and the contamination state on the back of the doctor blade and the surface of the developing sleeve was confirmed after 100,000 sheets. The image density unevenness was also evaluated, and the results are shown in Table 3.

[0063]

[Table 3]

[0064]

As is apparent from the above detailed and specific description, the developing device in which the developer regulating member is not contaminated, the developing device in which the developer carrying member is not contaminated, and the state of use of the developing device It is possible to provide a developing device capable of outputting a stable image density regardless of the image forming apparatus, a small and inexpensive image forming method / apparatus that does not require a toner replenishing mechanism and a toner density sensor, and a developer used therefor. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an image forming apparatus of the present invention.

[Explanation of symbols]

1 Latent image carrier (photosensitive drum) 13 Development device 14 Support case 14a Support case protrusion 14b Support case facing surface 14c Toner end sensor 15 Developer support (development sleeve) 16 developer accommodating member 16a developer container 17 First regulating member (first doctor blade) 18 toner 19 Toner container (toner hopper) 20 Toner supply opening 21 Toner supply means (toner agitator) 22 Developer 22a Magnetic carrier 23 Second regulating member (second doctor blade) X Interface (interface) Y developer confluence a Development sleeve rotation direction b Carrier circulation direction c Peeling developer drop path α Opposing surface inclination angle l Opposing surface length

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 9/113 G03G 9/10 352 15/06 101 15/08 507L 507Z (72) Inventor Fumihiro Sasaki Tokyo 1-3-6 Nakamagome, Ota-ku F-term in Ricoh Co., Ltd. (reference) 2H005 AA02 AA08 BA06 CA12 CA26 CB13 FA02 2H073 BA02 BA03 BA12 BA13 CA03 2H077 AA16 AB03 AB04 AB13 AB15 AC16 AD06 AD13 AD16 AD18 AD23 AD31 AD35 BA07 BA08 CA04 DA16 DA35 DA63 DB01 EA03 GA03

Claims (6)

[Claims] 1. A developer carrying member which has a magnetic field generating means inside and carries and conveys a two-component developer consisting of a magnetic toner composed of at least a binder resin and a magnetic material and a magnetic carrier composed of at least a magnetic material. A first regulation member that regulates the amount of the developer carried and carried by the developer carrier, and a developer accommodating portion that accommodates the developer scraped off by the first restriction member, A toner accommodating portion adjacent to the developer accommodating portion for supplying toner to the developer bearing member, wherein the toner concentration of the developer on the developer bearing member changes, and thereby the developer and the toner are separated from each other. A developing device for changing a contact state to change a toner taking-in state of a developer on the developer carrier, wherein the developer accommodating portion is arranged on the developer carrier more than a first regulating member. Located on the upstream side of the developer transport direction Has a second regulating member provided,
The second regulation member is configured to regulate the developer in order to regulate passage of the increased amount of the developer when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. A developing device, in which a gap is set with respect to a carrier, and an electric field is formed between the first regulating member and the developer carrier. 2. The developing device according to claim 1, wherein the electric field formed between the first regulating member and the developer carrying member is an alternating electric field. 3. The developing device according to claim 1, wherein the magnetic carrier comprises at least a coating layer containing a silicone resin as a main component. 4. The developing device according to claim 1, wherein silica fine powder treated with silicone oil is added to the magnetic toner. 5. The developing device according to claim 1, wherein a toner density sensor is not used. 6. The developing device according to claim 1, wherein an image density sensor is not used.