JPS6215558A - Magnetic developer - Google Patents

Abstract

PURPOSE:To obtain stable high image density from an early stage without fog and scattering and to reproduce a stable image unaffected by the lapse of time, and changes of temperature and humidity by incorporating a magnetic toner, a positively electrifiable fine silica powder, and an oxide powder of an element in group IIIb of the periodic table in the magnetic developer. CONSTITUTION:The positively electrifiable magnetic toner is composed of the magnetic toner, the positively electrifiable fine silica powder triboelectrifiable with an iron powder carrier to >=+5muC/g, such as SiO2 anhydride, and the fine oxide powder of an element in group IIIb of the periodic table, such as B2O3, preferably, having a particle diameter of 0.01-3mum. The fine silica powder having a specific surface area of 50-400m<2>/g exhibits good results. Said metal oxide is added, preferably, in an amount of 0.2-5pts.wt. per 100pts.wt. of the toner.

Description

Detailed Description of the Invention "Industrial Application Field 1 The present invention relates to a developer for developing latent images in electrophotography, electrostatic recording, electrostatic printing, magnetic recording, etc. Alternatively, the present invention relates to an electrophotographic developer that is uniformly and strongly positively charged, visualizes a negative electrostatic charge image, and provides a high-quality image in an indirect electrophotographic development method.

[Summary of Disclosure 1] This specification and drawings describe a positively charged magnetic developer used for direct or indirect electrophotographic development, in which the magnetic developer contains a magnetic toner, a positively charged silicon fine powder, and a material according to the periodic table. IIIb
By containing oxide powder of elements belonging to the group, it is possible to obtain stable high image density from the initial stage without fogging or scattering, and to reproduce stable images that are unaffected by changes in temperature and humidity over time. It discloses the technology.

[Conventional technology] Conventionally, electrophotography has been carried out using the following procedure.

■Charging of the photoconductive layer→re) Photoimage exposure (latent image formation)→■Adhesion of toner (development)→■Transfer to paper, cloth, etc.→■Development method in electrophotography by heating and pressurizing (fixing) There are many well-known four-component components, developability and component, and development method.

The former is a widely used method, such as the cascade method or the magnetic brush method, in which a two-component toner consisting of a mixture of 1.2 toner and carrier particles is used for development. All of these methods D: relatively stably produce good images, but on the other hand, they have common problems associated with two-component developers, such as deterioration of the carrier and fluctuations in the mixing ratio of toner and carrier.

In order to avoid the turtle, the carrier is included,
A variety of methods have been proposed using an image type, but among these methods, many are superior to methods using a developer made of magnetic toner particles.

The MagneDry method (U.S. Patent No. 3.!II (H,2!li8)) using conductive magnetic toner avoids the problems of the two-component development method, but since the toner is conductive, the developed image The problem is that it is difficult to electrostatically transfer it to a final support member such as plain paper.

In addition, when a high-resistance magnetic toner is used, electrostatic transfer is possible, and there is a development method that utilizes the dielectric polarization of this toner, but the development speed is slow due to the woody nature of the toner, and the density of the developed surface is In addition, other methods using resistive magnetic toner in 1.
・A method is known in which toner particles are charged by friction between the toner particles Rf or with a sleeve, etc. However, the number of times the toner particles come into contact with a friction member is small, and the frictional charging tends to be insufficient. The problem was that the Coulomb force between the sleeve and the sleeve was strong and the sleeve agglomerated easily.

, Applicant □ previously proposed a new developing method in JP-A-55-42-141 which eliminates the problems mentioned above.

This is a jumping method in which an extremely thin layer of insulating magnetic toner is applied to the sleeve 1-, it is triboelectrically charged, and the toner is developed by being placed very close to and opposing the electrostatic image under the action of a magnetic field and causing the toner to fly. It is. According to this method, the sleeve and the toner are bonded. Increase the degree 1. -As a component developer, it enables good frictional electric current, supports and supports the toner by hair and magnetic force, and also moves the toner particles relative to the stone to prevent mutual agglomeration. As it comes undone, it causes sufficient friction with the sleeve. Su1
In addition, excellent images can be obtained because the toner is developed directly facing the electrostatic image without coming into contact with it, thereby preventing ground blurring. Only 8. However, even with this method, the amount of tripo charge that the toner particles have is
Normally, the amount of charge is extremely small compared to the amount of tripoelectricity and charge in normal two-component development.

These, such as U: retain a weak electrical charge in measles,
1. When used, 1: Low image density, scattering, blurring, unevenness of image, etc. 11. Insufficient image quality, 72. ．． 6. In particular, the initial density is low, and it usually takes several hundred copies to reach a constant density.
This is one of the major problems in system development. Also, increase the image density by 1 degree. There was a problem with the image bias, such as when the image was lowered, causing the image to become foggy.

For this reason, it was necessary to improve the tripo (+?electro!) pores of the magnetic toner.As a 18th step, it is known to add silicic acid fine powder to negatively charged developers. , image density and image quality have been improved, and images that are satisfactory to some extent have been obtained.However, 11. Generally, silicic acid fine powder has a strong negative charge, and it is necessary to add negatively charged silicic acid fine powder to a positively chargeable developer. However, a good image cannot be obtained.
.

- Generally, toner contains a charge control agent for the purpose of obtaining desired polarity and charge strength. Examples of positive charge control agents include generally quaternary ammonium compounds and organic tetraorganic dyes, particularly basic dyes and their salts. Common positive charge control agents include benzyldimethyl-hexadecyl ammonium chloride, tesyltrimethylammonium chloride,
These include mucrolite, nigrosine lti M, nigrosine, safranin γ, and crystal piolene l-. In particular, di-crocine base and nigrosine are often used as positive charge control agents. These are usually added to magnetite and a thermoplastic resin, heated, melted and dispersed, and pulverized to a suitable particle size as required before use.

[Problems to be Solved by the Invention] However, these dyes used as charge control agents have complex structures, inconsistent properties, and poor stability. In addition, it is easy to decompose or change in quality due to decomposition during heat kneading, mechanical shock, abrasion, changes in temperature and humidity conditions, etc. This can easily lead to a phenomenon in which controllability deteriorates.

Therefore, use the 1ner using these charge control agents in the machine! /) During development, as the number of copies increases, the charge control agent decomposes or changes in quality, which may cause deterioration of the toner during durability.

In addition, there are also horse-charged kanigyaku-naka and parent-like ones.

Due to poor dispersion into these resins, 1. After melting and kneading, one part of the control agent is exposed on the surface of the toner when it is ground.

Therefore, when the toner is used under high humidity conditions, there is a problem that good quality images cannot be obtained because these control agents are wood-philic.

In this way, when a conventional positive charge control agent is used in a toner, between toner particles, between a toner and a carrier, or between a toner and a toner carrier such as a sleeve,
The amount of charge generated on the surface of toner particles varies, and problems such as development fog, toner scattering, and carrier contamination are likely to occur.

When the toner is stored for a long period of time, it often deteriorates and becomes unusable due to the instability of the positive charge control agent used.

Therefore, there is a method in which silicic acid fine powder, which is originally negatively charged, is modified to be positively charged and added. For example,
No. 447 and JP-A No. 58-185405, a method of incorporating a fine silicic acid powder treated with aminosilane into a toner, and a fine powder of silicic acid treated with a silicone oil having an amine in its side chain. Attempts have been made to include the body.

By adding such positively charged silicic acid fine powder, it is possible to obtain clear, high-density images that are relatively fog-free, but the problems caused by the above-mentioned tripo-electrification property cannot be sufficiently resolved. The current situation is that we have not yet reached that point.

Although the present invention has been made in view of the problems of the prior art described in I-,
Therefore, our objective is to provide a positively charged magnetic developer that can stably produce snow images with no fog, clear crystallinity of 118 degrees, and no fluctuation in IM degree especially during the initial stage. do.

Means and operation for solving the L problem J'-According to the present invention, a magnetic toner, positively charged silicic acid fine powder, and oxide powder of Yuan, Feng, which belongs to Group IIIb of the periodic table. A positively charged magnetic developer is provided.゛The periodic table mentioned here is from Rikachu Dictionary (Iwanami Shoten, 3rd edition)
P, 1484.

Therefore, the positively charged silicic acid fine powder has a charge amount of +t,,', c/, and l-4 with respect to the iron powder carrier.

This charge amount measurement begins with: - Test substance (silicic acid fine powder)
With an iron powder carrier having a particle size of 2007ao'o mesh! : 100-1 go mixed 6'4, 0
．． Accurately weigh 5 to 1.5 g. This is connected to a metal 400 mesh screen 1-25 connected to an electrometer.
The amount of charge per unit weight is determined from the sample substance separated and attracted by the pressure of C fat H20 and its amount of charge.

1. In this specification, silicic acid fine powder refers to anhydrous silicon dioxide (silica), aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate, etc. Refers to silicates, etc.

In addition, in this specification, "magnetic developer" and "magnetic developer" are used for convenience.
Although 62 types of "toner" are used, "toner" is a part of "magnetic developer" and includes binder resin, magnetic material, dye, pigment, charge control agent, flow modifier, lubricant, etc. It consists of a φ□ acid component selected from the following, to which positively charged silicic acid fine powder, an oxide of Group M3 of the periodic table, carbon and other additives are added as necessary. This material is called a "magnetic developer."

The silicic acid fine powder used in the present invention is produced by a dry method or a wet method. The dry method is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halide compound. For example, silicon tetrachloride is expressed by the following reaction formula.

5iCR4+ 2H2+ (h+ 5i02 + 4
IICj! It also includes a composite fine powder of silica and other metal oxides obtained by using other metal halide compounds such as aluminum chloride or titanium 11j chloride together with a silicon halide compound during this T step. Commercially available silicic acid fine powders (silica) produced by the dry process include the following:

AERO3IL (Aerosil) 130 (Japan Aerosil) 200 x50 T600 OX80 MOX 170 0K84 Cab-0-5iL (Cab-0-5iL) M-5GA
BOT Co, (Capot Co.) MS-
7MS-5 H-5 Wacker HDK N 20
VI5WACKER-GHENI
E GMBHN20E (Wackel Hemi 10M88
Tau Corning Inc.) T30D-CFine 5ilica (7y-in silica) Tau Corning Inc. Fransol (7 Ransol) Fransil (7 Ransol) Further, as the wet method, there are various conventionally known methods. For example, decomposition of sodium silicate with acid, ammonia salts or alkali salts, a method of generating alkaline earth metal silicate from sodium silicate and then decomposing it with acid;
There is a method of converting a sodium silicate solution into silicic acid using an ion exchange resin.

Commercial products of silicic acid fine powder synthesized by a wet method include the following.

Carplex Shionogi & Co. Nip Seal Nippon Silica Toxeal, Fine Seal Tokuyama Soda Vita Seal Taki Hijiruton, Silnex Mizusawa Kagaku Starsil
Mythical Chemistry Himezil Ehime Yakuhin Thyroid Totevison Chemical Old-
3il (High Seal) Pittsburgh Plate Glass Ca
-(Bitz 8-ri Plate Glass) Durosil Ultrasil Fillst
off-Gesellschaft Marquardt
Manosil (f no seal) Hardman and Ho1den (hardman
Hoesch Ghe++1sche Fabrik Hoesch
K-G (Hiemische Fabrik Herrash) Si
l-3tone Stoner
Rubber Co.

(Stoner rubber) Nalco (Nalco) Nalco Chew, Go.

(Narco Chemical) Quso (shoes) Philadelphia Quartz Co.

(Philadelphia Quartz) Santocell (Santocell) Monsant
o, Chemical Co.

(Monsanto Chemical) In+sil (Imusil) +11inois Minerals Co.

(Illinois Mineral) Calcium 5ilikat (Calcium Silicate) Ghemische Fabrik Hoe
sch, K-G Calsil Fiillstoff-Gesellschaft M
arquartFortafil (7t lutafil)
Imperial Che+n1cal Industry
ries Ltd.

Microcal Manosil Mardman and ) Iolden Vulkasil Farbenfabriken Bayer, A, -
G.

(Falpenfabriken Bayer) Tufkni
t (tough knit) Durham Chemicals Ltd.

(Durham Chemicals) Silmos Shiraishi Rigyo Starex Shingu Kagaku Fricocil
Among the silicic acid fine powders mentioned above, those with a specific surface area due to nitrogen adsorption measured by the BET method of 30 m2/g or more (especially 5
0 to 400 m2/g) gives good results. .

When these fine silicic acid powders are modified to have a positive charge and are incorporated into a developer, charge controllability is exhibited. There are methods such as treatment with silicone oil and treatment with aminosilane.

As the silicone oil having an amine in its side chain, silicone oil containing a structural unit represented by the formula (1) is generally used.

I The group, aryl group, alkoxy group, alkylene group, and phenylene group may contain an amine, or may have a substituent such as a halogen within a range that does not impair chargeability.) Among these, commercially available For example, those represented by the following structural formula S can be preferably used.

(Here, R,, R5 represents an alkyl group or an aryl group, R2 represents an alkylene group or a phenylene group,
R3 represents hydrogen, an alkyl group, or an aryl group. ,,.

is an integer greater than or equal to 1. ) Specifically, the following are preferable, and one type or a mixture of two or more types may be used.

Product name ゛ Viscosity (cps) at 25°C
,'y = 'To! Haruka 5F8417 (,,)-
(manufactured by Les Silicones) 1200. , 35
00KF393 (manufactured by Shin-Etsu Chemical) 606KF857
(Manufactured by Shin-Etsu Chemical Co., Ltd.), 70
830KF880 (manufactured by Shin-Etsu Chemical)
250 71300KF881
(manufactured by Shin-Etsu Chemical) 3500.
2000KF8B・2 (manufactured by Shin-Etsu Chemical Co., Ltd.)
,,j501900KF884 (manufactured by Shin-Etsu Chemical Co., Ltd.), 1700 3800
O <F2O3 (manufactured by Shin-Etsu Chemical Co., Ltd.)” 90
4400 (F3B!1 (manufactured by Shin-Etsu Chemical) 2032° (F2O3 (manufactured by Shin-Etsu Chemical) -20320<-22-
3680 (manufactured by Shin-Etsu Chemical) 90
8800 (-22-380D (manufactured by Shin-Etsu Chemical)
2300' 3800 (-22-
38010 (manufactured by Shin-Etsu Chemical) 3500
3800 (-22-3810B (manufactured by Shin-Etsu Chemical Co., Ltd.) 1300-1700 The amine equivalent is the equivalent per amine (g/eqiv
) is the value of the y molecular star divided by the number of amines per molecule. Further, the viscosity at 25° C. is preferably 5000 cps or less, particularly preferably 3000 cps or less. 50
If the speed is less than 00 cps, the dispersion into the silicic acid fine powder becomes insufficient, which tends to cause defective images such as fog.

-1; The treatment of fine silicic acid powder with a silicone oil having an amine in its side chain can be carried out, for example, as follows. The fine silicic acid powder is vigorously stirred while being heated if necessary, and then the silicone oil having an amine in the side chain or its solution is sprayed or vaporized, or the fine silicic acid powder is slurried. It can be easily treated by adding a silicone oil having an amine in its side chain or a solution thereof while stirring the mixture. At this time, the additive amount of the silicone oil having an amine in the side chain should be 0.2 to 7 oiHλ percent of the total amount of the treated silicic acid fine powder, and 0.0001 to 10 percent by weight in the developer. It is better to

Furthermore, the aminosilane used for surface treatment of silicic acid fine powder is a so-called amine functional silane having the general formula: X, S i Y.

(X is an alkoxy group or a chlorine radical f, sho is an integer of 1 to 3, Y is a hydrocarbon group having a primary to tertiary amine group, and n is an integer of 3 to 1.) Compounds such as:

CH3 H2N-CH2CH2NHCH2CH2CIhSi-(
OCH3)2H2N-C:0NH-CH2CI2CH2
-8i-(OC2)15)3 q 82N-CH2(J2CH7Si(OCH2GIh)3
H2NCH2C1h NHCH2CH2CH2S i
(OCH3) 3H2Nf11:H2CH2CH2S1
(OCH3)3112NcH2cH2NHcH;+Ct
hNHCH2CtbCH2Si(OCtb)305G
70CO(Jb CH2CHC1h CH2Cl7 S
i (OCH3)385G20GOCH2CH2NH
(J(70H2NHCJ17 CH2Cl7 S i
(OCH3) 3H! , C20COCH2CH2NHC
H2CH2NHCH2Cl7 NHCH2CH2NHC
H2CH2CIh S i (OCH3)3NH2C6
)1nSi(OCH3hC6ToNHCH20H2CH2Si(OCH3)3 or polyaminoalkyltrialkogysilane, etc., and these may be used alone or in a mixed system of two types.

Thus, the surface of the fine silicic acid powder can be treated with aminofunctional silane, for example, as follows. That is, the silicic acid fine powder is stirred, and then the 1-aminosilane compound or its solution is sprayed or vaporized, or the silicic acid fine powder is made into a slurry, and the aminosilane is added to the slurry while stirring. It can be easily treated by dropping a solution of the compound. The amount of aminosilane added is 1.0 parts by weight per 100 parts by weight of silicic acid fine powder.
The amount is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight.

Alternatively, as described in Japanese Patent Publication No. 54-IB220t, IF-chargeable silicic acid fine powder may be obtained by reacting the silanol groups on the surface of the silicic acid fine powder with an organosilicon compound.

Further, the silicic acid fine powder used in the present invention may be further treated with a conventionally known hydrophobizing agent as necessary, and a known method may be used for this treatment, such as reaction or physical treatment with the silicic acid fine powder. +1 goo can be obtained by chemically treating it with an adsorbing organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane,
Allyl phenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyl i-lichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, silylmercaptan, triorganosilylacrylate, Vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyljethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 1 per molecule.
There is dimethylpolysiloxane which has two siloxane units and contains one Si-bonded hydroxyl group in the middle position at each end. These may be used alone or in a mixture of two or more.

In this way, fine silicic acid powder whose surface has been treated with silicone oil or aminosilane having an amine in its side chain is kneaded and blended with a resin as a binder and a coloring agent, which are other constituent components of the developer, and then pulverized and classified. The required developer is obtained. Incidentally, the surface treatment of the fine silicic acid powder may be carried out during this developer preparation process. That is, in the process of kneading and blending the required silicic acid fine powder with a resin or the like as a binder, silicone oil or aminosilane having an amine in the side chain is added and the surface treatment of the silicic acid fine powder is carried out along with the kneading and blending. You may do so.

The application of the thus treated fine silicic acid powder is effective when the amount is 0.01 to 20 parts by weight, particularly preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner. It exhibits positive chargeability with excellent stability.

Examples of oxides of Group IIIb elements that can be suitably used in the present invention include boron oxide, aluminum oxide, gallium oxide,
There are indium 12, tali oxide, and um, among which boron oxide includes 5#1 diboron B2O3, diboron dioxide B2 (12, TF, oxidation, decoy boron B4O
Examples include 3.H2,0, tetraboron pentoxide 8405, and the like.

Diboron trioxide can be easily obtained by a known manufacturing method. When boric acid is melted in a platinum crucible and dehydrated, Q is obtained (2H3'BQ3→B2O3'+ 'jH2
0) It is a waxy glassy substance and is usually widely available commercially in the form of white fine powder. If the purity is 8'5% or more for a first-class reagent, it can be applied to the present invention. In addition, aluminum oxide AR20s (1±), which is generally commercially available as a reagent and for industrial use, can be suitably used. The method for producing it is to precipitate aluminum hydroxide from an aqueous solution of a soluble aluminum salt, filter it, and then ignite it. Industrially, method b is called the Bayer method (the most widely used method, and its lK
]! The reason is that when bauxite is treated with thorium hydroxide, aluminum is cocooned as an aluminate, but SjO'2' and Fe2O3 + Ti02 in the ore precipitate, so they can be separated. A sodium aluminium leprosy solution is hydrolyzed to precipitate AMOHh, which is then baked to obtain non-hygroscopic α-ARi03. In addition to this α-type alumina, various other transformations such as β-type and γ-type are known, and any of them can be suitably used in the present invention.゛The content of these metal oxides is 0.1 to 20% by weight, preferably 0.2 to 5% by weight, based on 100 parts by weight of the toner.
It is desirable to contain it in an amount of .mu.% by weight. The particle size is
It is desirable that it be 5 IL or less, preferably in the range of 0.01 to 3 IL. □ All known binder resins can be used in the present invention, such as polyethylene, poly-p-
Medium-sized polymers of styrene and its substituted products such as chlorostyrene and polyvinyltoluene; methylene-P-chlorostyrene copolymer, styrene-P-pyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Acrylonitrile copolymer, methyl ethylene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer,
Styrene-butyl methacrylate copolymer, styrene-α
methyl methacrylate copolymer, styrene
Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, methyl vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, -Acrylonitrile-indene□
Polymer, styrene-marinic acid copolymer, styrene-
Styrenic copolymers such as maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyvinyl chloride, polyurethane,
Epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin.

Rosin, modified rosin, terpene resin, finol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin,
Chlorinated paraffin, paraffin, wax, etc. may not be used alone or in combination.

When this binder resin contains a magnetic material and is made into particles, the particle size is 1゛5'~30#L, which is the general toner particle size.
In addition, as the magnetic substance contained in the binder resin, ferromagnetic elements such as iron, cobalt, and nickel, and alloys and compounds containing them such as magnetite, hematite, and ferrite can be used as appropriate. . Its particle size is 100~
The pot is 800 m pL, preferably 300 to 500 m, and preferably contains 30 to 100 parts by weight, more preferably 40 to 80 parts by weight of the binder resin.

In addition, this magnetic toner contains a charge control agent, a flow modifier,
Colorants, lubricants, etc. may be added (externally added) or included (
(Internal attachment) does not impede the present invention in any way.

In producing the magnetic toner of the present invention, a method can be applied in which the constituent materials are thoroughly kneaded using a heat kneader such as a hot roll, kneader, or extruder, followed by mechanical pulverization and classification.

Further, in order to add and contain each of the above-mentioned inorganic powders into the magnetic toner, a known mixer can be used, such as a rotary container type mixer such as a V-type mixer, a tarpaulin mixer, a ribbon type, screw type, rotary blade type, or other fixed container. A mold mixer can be used as appropriate.

Alternatively, a material such as magnetic powder is dispersed in a binder resin solution and then spray-dried. Various methods can be applied, such as a polymerization method and a toner production method in which a magnetic toner is obtained by polymerizing a suspended liquid.

"Example" The present invention will be explained in more detail with reference to Examples below.

100 parts by weight Low molecular weight is polyethylene wax 4 parts by weight The materials listed in 1- are mixed and melted and kneaded in a roll mill. After cooling, it is roughly pulverized using a hammer mill, and then finely pulverized using a Zitz pulverizer. Next, the particles were classified using an air classifier to obtain a magnetic toner having a particle size of approximately 5 to 30 μm.

] - Magnetic toner containing various i[charged silicic acid fine powder and I
A magnetic developer was prepared by adding a group IIb element oxide and others.

Example 1 Silicic acid fine powder synthesized by dry method (trade name Aerosil #
130, specific surface area approximately 130 m2/g; manufactured by Aerosil Co., Ltd.) was heated at 250°C without stirring, and a silicone oil having an amine in the side chain (KF85?
, viscosity at 25°C 70 cps, amine equivalent weight 8
No. 30 (manufactured by Shin-Etsu Chemical Co., Ltd.) 20 heavy seams were sprayed and treated for 10 minutes.

0.4 parts by weight of silicic acid fine powder treated with silicone oil having an amine in the side chain shown in L and 2 parts by weight of diboron trioxide (B203, grade 1 reagent manufactured by Tokyo Kasei Co., Ltd.) were placed on 100 layers of the magnetic toner. The mixture was added externally to prepare a magnetic developer.

Example 2 Silicic acid fine powder synthesized by dry method (Aerosil 0X-5
0. Specific surface area approximately 50m? /g; made by Aerosil) 1
00 parts by weight of silicone oil with amine in the side chain (
KF393. Viscosity at 25°C 80 cps, amine equivalent 360. A magnetic developer was obtained in substantially the same manner as in Example 1, except that a developer treated with a single double star (manufactured by Shin-Etsu Chemical) was used.

Example 3 Silicic acid fine powder synthesized by dry method (Aerosil $120
0, specific surface area 200m? /g; manufactured by Aerosil) 1
00 parts by weight of silicone oil Jl with amine in the side chain
/ (X=22-380IC viscosity 3 at 125°C
500 cps, amine equivalent 3800, Shin-Etsu Chemical) 40
Example 1 except that the one treated with heavy seams is used.
A magnetic developer was obtained in substantially the same manner as above.

Example 4 Silicic acid fine powder synthesized by wet method (Purkasil C, specific surface M about 80 m?/g; manufactured by Falpenfabriken Bayer) 100 parts by weight of silicone oil having amine in the side chain 0'-22- 3810B, viscosity +300
A magnetic developer was obtained in substantially the same manner as in Example 1, except that a developer treated with 10 parts by weight of cps, amine equivalent 1700, manufactured by Shin-Etsu Chemical was used.

Example 5 Silicic acid fine powder synthesized by dry method (Aerosil $138
0, specific surface area 380m27g; Aerosil formal dress) 1
Silicone oil with amine in the side chain of 00-polymer moiety (
A magnetic developer was obtained in substantially the same manner as in Example 1, except that a developer treated with 40 parts by weight of KF882, viscosity 750, amine 5 1806 (Shin-Etsu Chemical) was used.

Example 6 Silicic acid fine powder synthesized by wet method (Nalco Gel-10
0, specific surface area 120127g; manufactured by Nalco Chemical) 1
00 parts by weight of silicone oil having an amine in the side chain (SF8417, viscosity 1200 cpg, amine equivalent 3)
A magnetic developer was obtained in substantially the same manner as in Example 1, except that the developer treated with L part was used.

Example 7 Silicic acid fine powder synthesized by dry method (Aerosil Key 200
, specific surface area 2001? /g; manufactured by Aerosil) 100
While stirring the parts by weight, 2 parts by weight of γ-7 minoprobiltriethoxysilane (A-1100, Nippon Unicar Co., Ltd.) diluted with 20 parts of 80% ethanol was added dropwise using a dropper. After stirring was continued for 3 minutes after the addition, the powder liquid was transferred to a vat and heated in a dryer at 110° C. in a nitrogen gas atmosphere for 1 hour to remove ethanol. While stirring the powder again, a solution prepared by diluting 4 parts by weight of hexamethyldisilazane with 18 parts by weight of hexane is dispersed in the same manner as described above, and the hexane is removed. The powder thus obtained was transferred to a 1-liter flask equipped with a reflux condenser, a stirring tank, and a thermometer, and heated at 150°C for 4 hours.
FJ! Heat for 1 hour.

A magnetic developer was obtained by externally adding and mixing 4 parts by weight of the silicon # fine powder treated with the aminosilane and 2 parts by weight of diboron trioxide to 100 parts by weight of the magnetic toner.

Example 8 A magnetic developer was obtained in the same manner as in Example 1, except that carbon (414G manufactured by Seiyo Kasei Co., Ltd.) 0.5-layer lid was also externally added and mixed.

Example 9 Aluminum oxide (Ai) was used instead of 2 parts by weight of boron oxide.
A magnetic developer was obtained in the same manner as in Example 1, except for externally adding and mixing 2 parts ('2h, Tokyo Kasei reagent grade 1).

Example 10 Aluminum oxide (^h) instead of 2 parts by weight of boron oxide
03. A magnetic developer was obtained in the same manner as in Example 2, except that 2 parts by weight of reagent grade 1) manufactured by Tokyo Kasei Co., Ltd. was externally added and mixed.

Example 11 Aluminum oxide (Ai) was used instead of 2 parts by weight of boron oxide.
'z03. A magnetic developer was obtained in the same manner as in Example 3, except for externally adding and mixing the double acid moiety (reagent grade 1) manufactured by Tokyo Kasei Co., Ltd.

Example 12 Aluminum oxide (Al
A magnetic developer was obtained in the same manner as in Example 4, except that a double acid moiety (103, Tokyo Kasei Reagent Grade 1) was added and mixed externally.

Example 13 Aluminum oxide (AI) instead of 2 parts by weight of boron oxide
! A magnetic developer was obtained in the same manner as in Example 5, except that 2 parts by weight of No. 203 (Reagent Grade 1, manufactured by Tokyo Kasei Co., Ltd.) was externally added and mixed.

Example! 4 Aluminum oxide (Ai) instead of 2 parts by weight of boron oxide
A magnetic developer was obtained in the same manner as in Example 6, except that 2 parts by weight of 'zG3, Tokyo Kasei Reagent Grade 1) was externally added and mixed.

Example 15 Aluminum oxide (Aj
)203. A magnetic developer was obtained in the same manner as in Example 7, except that 2 parts by weight of reagent grade 1) manufactured by Tokyo Kasei Co., Ltd. was externally added and mixed.

Example 1B Aluminum oxide (Ai
A magnetic developer was obtained in the same manner as in Example 8, except that 2 parts by weight of Reagent No. '203, manufactured by Tokyo Kasei Co., Ltd. (Reagent Grade 1) was externally added and mixed.

Comparative Example 1 Magnetic toner similar to the example lOO small jI: part negative 4ii
'Ichi t1 hydrophobic colloidal silicone force (Aerosil R97
2,11, surface area about 120 teng? /g, -t' engineering tff (manufactured by Shirun 1) 0.4 Φl, only part i was externally added and mixed 17, to obtain a magnetic 1 developer.

Comparative Example 2 A magnetic developer was obtained in the same manner as in Example 1 except that boron oxide was not externally added.

Comparative Example 3 A magnetic developer was obtained in the same manner as in Example 2 except that boron oxide was not externally added.

Comparative Example 4 Adding boron oxide 1. A magnetic developer was obtained in the same manner as in Example 3 with the exception of 1.

Comparative Example 5 Example 4 and studs (,'1,
A magnetic developer was obtained.

Comparative Example 6 A magnetic f1 developer was obtained in the same manner as in Example 5 except that boron oxidized was not externally added.

Comparative Example 7 A magnetic +1 developer was prepared in the same manner as in Example 6 except that boron oxide was not added externally.

Comparative Example 8 A magnetic developer ((J) was prepared in the same manner as in Example 7 except that boron oxide was not externally added.

Comparative Example 9 A magnetic +1 developer was obtained in the same manner as in Example 8 except that boron chloride was not added.

1. Room temperature and high humidity (25°C, 60%
RH), high temperature 1-h humidity (35°C185%RH),
Various environmental conditions of low temperature and low humidity (15°C, 110% RH)! 1F
The evaluation results of the images in Table 1 (normal temperature and humidity) and Table 2
Shown in the table (product temperature, high humidity, low temperature, low humidity). In the table, O is good, △
1 indicates that the developing power is slightly poor, and × indicates that the image is defective. Transferred to paper and heated for 1-7 minutes. For other examples and comparison side numbers, a jumping method compound machine (NP-1507, manufactured by Canon Mari) was used.
I created the image using fJL.

In each example, the obtained transferred images were all sufficiently dark from the first sheet, had no fogging, and had no toner scattering around the image, resulting in a good image with high resolution. In addition, we created continuous transfer images and examined the durability, but a
The transferred images after o and ooo sheets were also completely comparable to the initial images. At that time, so-called filmink development, in which toner sticks to the surface of the photoreceptor and adversely affects latent image formation, was not observed at all, and no problems were found in the cleaning process.

In addition, even if the environmental conditions are high temperature and high humidity (35°C, 85% RH) or low temperature and low humidity (15°C, 10% RH), you can obtain clear images that are almost the same as those under normal temperature and humidity. The results were obtained.

In Comparative Example 1, the image density was low at 0.42 at room temperature and humidity, the image density was low at 0.42, and the solid black was noticeably rough. Regarding durability, the density decreased to 0.20 after 30,000 sheets. In addition, from around 10,000 sheets, toner material formed a film in the form of thin stripes on the surface of the photoconductor, and the image began to appear in the form of lines (Filmink).
. Even under high temperature, high humidity, and low temperature and low humidity conditions, image density was low, and fogging, scattering, and roughness were noticeable.

In Comparative Examples 2 to 9, the image density was relatively high compared to Comparative Example 1, but the image density was unstable and it took about 100 sheets to saturate to a constant density. In addition, the density tended to decrease slightly under high temperature and high humidity conditions and when ao and ooo sheets were used in the durability test. Also, filming started to occur after around 10,000 copies.

[Effects of the Invention] As explained below, the magnetic developer of the present invention has a stable and uniform positive charging property, and can perform development and transfer faithful to a latent image. That is, there is no toner adhesion in the background area during development, that is, there is no fogging or toner scattering around the edges of the latent image, high image density is obtained, and halftone reproducibility is also good. Furthermore, there is no fluctuation in image density and the image density is high from the beginning.

Further, the magnetic developer of the present invention maintains its initial characteristics even after long-term continuous or repeated use and long-term storage, and has good resistance to filming and cleaning f1. In addition, it is a magnetic developer that produces low-T images that are unaffected by changes in temperature, i' and Il'V, and does not scatter, roll, or come off even in high or low humidity.

Claims (1)

[Claims] 1) Magnetic toner, positively charged silicic acid fine powder, and I of the periodic table
A positively charged magnetic developer containing at least an oxide powder of an element belonging to Group IIb. 2) The mixing ratio of the positively charged silicic acid fine powder is 1 for the magnetic toner.
The developer according to claim 1, wherein the amount is 0.01 to 20 parts by weight based on 0.00 parts by weight. 3) The developer according to claim 1, wherein the mixing ratio of the oxide is 0.1 to 20 parts by weight per 100 parts by weight of the magnetic toner. 4) The developer according to claim 1, wherein the oxide has an average particle size of 0.01 to 5 μm. 5) The developer according to claim 1, wherein the magnetic toner has an average particle size of 5 to 30 μm.