JPH11288131A - Binder carrier using specified resin as binder resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of a carrier due to a toner component and to exhibit the stable charging property over a long time with little deterioration in the electrification performance by incorporating a copolymer containing ethylene-type unsatd. nitrile, silicone-modified acryl resin and amino group-contg. resin into a binder resin. SOLUTION: This binder carrier consists of magnetic powder and a binder. The binder resin contains a copolymer containing ethylene-type unsatd. nitrile, silicone-modified acryl resin and amino group-contg. resin. The amts. of ethylene- type unsatd. nitrile copolymer, silicone-modified acryl resin and amino group- contg. resin to the binder resin are 5 to 95 wt.%, 3 to 90 wt.% and 2 to 70 wt.%, respectively. Thereby, deterioration of the carrier by the toner component is prevented and stable charging property is exhibited over a long time with little deterioration in the electrification performance. Even when the toner is rapidly replenished, an image of high image quality can be stably obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier used for a two-component developer of an image forming apparatus such as a digital copying machine or a printer, and more particularly to a binder carrier obtained by dispersing a magnetic powder in a binder resin. is there.

[0002]

2. Description of the Related Art In an electrophotographic copying machine or a printer, a two-component developer composed of a toner and a magnetic carrier is used for developing an electrostatic latent image formed on an image carrier such as a photoconductor. The two-component developing method has been put to practical use.

Various carriers are known as a carrier for a two-component developer, such as an iron powder carrier, a ferrite carrier, a resin-coated carrier in which these magnetic particles are coated with a resin, and a binder carrier in which magnetic fine particles are dispersed in a binder resin. Have been. However, when the resin-coated carrier is conveyed as a magnetic brush onto the developing roller, its spikes are hard, so that a smooth image cannot be obtained. Scratches are a problem. In addition, the resin-coated carrier also has a problem that the life of the developer is short because the coating layer is peeled off as it is used.

[0004] A binder carrier has been attracting attention as a carrier that solves the above-mentioned problems, is easy to reduce the particle size, has a high volume specific electric resistance, and hardly injects charges from a developer carrier.

[0005]

However, in a normal binder carrier, as the toner is used, the toner itself,
The charge control agent or post-treatment agent of the toner adheres to the surface of the carrier, thereby deteriorating the charge performance of the carrier, making it impossible to sufficiently charge the toner, causing toner scattering, or an image formed on a sheet. In addition, there is a problem that image noise such as fogging occurs, and the toner charging speed becomes slow, so that fog and image density unevenness occur when toner is rapidly replenished.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent carrier deterioration due to toner components such as a charge control agent and a post-treatment agent, and to stabilize the charge performance over a long period of time with little deterioration in charge performance. It is an object of the present invention to provide a long-lasting binder carrier that can exhibit chargeability and can stably obtain high-quality images even when toner is rapidly supplied, and has excellent durability.

[0007]

The present invention relates to a binder carrier comprising at least magnetic powder and a binder resin, wherein the binder resin contains at least an ethylenically unsaturated nitrile, a silicone-modified acrylic resin and an amino group-containing resin. The present invention relates to a binder carrier comprising:

The copolymer resin containing an ethylenically unsaturated nitrile component contained in the binder resin of the carrier of the present invention has positive chargeability and excellent non-staining properties, and the silicone-modified acrylic resin contained at the same time is negatively charged. It has properties of low viscosity and low surface energy, is excellent in deterioration resistance, and is also excellent in compatibility with an ethylenically unsaturated nitrile component-containing copolymer resin. In addition, since the amino group-containing resin has a strong positive charge property, the toner can be charged quickly.
By using such a resin in this manner, it is possible to impart sufficient charge to both the positively charged toner and the negatively charged toner, reduce the adhesion of the toner component to the carrier, and maintain a stable state for a long time. Chargeability can be maintained.

The ethylenically unsaturated nitrile, which is a component of the copolymer as the binder resin of the present invention, is represented by the following general formula (1):

Embedded image In the formula, R1, R2, and R3 each independently represent a hydrogen atom,
Represents an alkyl group. Examples of the alkyl group include lower alkyl groups such as methyl, ethyl and propyl. Specifically, acrylonitrile, methacrylonitrile, and ethacrylonitrile are preferable, and acrylonitrile is particularly preferable.

[0010] The ethylenically unsaturated nitrile accounts for 40 to 90% by weight, preferably 50 to 80% by weight of the total copolymer component. If the amount is too large, polymerization becomes unstable when synthesizing the copolymer, and the obtained resin also becomes hard, making it difficult to produce a binder carrier. If the amount is too small, the polymerization becomes unstable and the resin itself cannot be produced.

The radically polymerizable organic monomer copolymerized with the ethylenically unsaturated nitrile is represented by the following general formula (2):

Embedded image Is an acrylic organic monomer represented by

R4 represents a hydrogen atom or an alkyl group. Examples of the alkyl group include C1 to C4, preferably C1 to C2, lower alkyl groups. Among these, a hydrogen atom and a methyl group, particularly a hydrogen atom, are preferred.

R5 represents a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include C1 to C4, preferably C1 to C2, lower alkyl groups. Among them, methyl group,
An ethyl group is preferred, and an ethyl group is particularly preferred.

The acrylic organic monomer accounts for 60 to 10% by weight, preferably 50 to 20% by weight of the ethylenically unsaturated nitrile copolymer component. If the amount is too large, the amount of ethylenically unsaturated nitrile relatively decreases, and the above effect cannot be obtained. On the other hand, if the amount is too small, the polymerization becomes unstable and the resin itself cannot be produced.

In the present invention, the ethylenically unsaturated nitrile copolymer may further contain a rubber component. By including a rubber component, it is effective to prevent deterioration of the carrier, and the durability can be further improved.

The rubber component may include conjugated diene-acrylonitrile rubber such as butadiene, isoprene, 2,3-dimethylbutadiene, butadiene-acrylonitrile rubber, and conjugated diene-styrene rubber such as butadiene-styrene rubber. Butadiene is particularly preferred.

When the rubber component is contained, the amount is from 0 to
50% by weight. Even if the content is more than 50% by weight, the obtained copolymer resin becomes hard, and it becomes difficult to produce a binder carrier.

The ethylenically unsaturated nitrile copolymer used in the present invention comprises the above-mentioned ethylenically unsaturated nitrile of the general formula (1) and a radically polymerizable organic monomer of the general formula (2), and optionally a rubber component. It can be obtained by copolymerizing in the presence of a radical polymerization initiator such as bisisobutyronitrile (AIBN).

At this time, the finally obtained copolymer has a melt index (MI) value of 150 ° C./2.16 k
The value measured under the condition of g / 10 minutes is 1.0 to 5
0, preferably 1 to 40, more preferably 1.5 to 38
It is manufactured so as to be within the range. If the value is too small, melt kneading cannot be performed during carrier production. On the other hand, if the value is too large, fusing tends to occur during the pulverizing step in carrier production. Also, when expressed in terms of molecular weight, it corresponds to one having a number average molecular weight (in terms of styrene) of about 30,000 to about 150,000.

The silicone-modified acrylic resin constituting the binder resin of the carrier of the present invention is obtained by copolymerizing a polydiorganosiloxane macromer having an acrylic functional group and a radically polymerizable organic monomer.

The polydiorganosiloxane macromer having an acrylic functional group has the general formula (3):

Embedded image It is represented by

In the above formula, R11 represents a hydrogen atom or an alkyl group. Examples of the alkyl group include C1 to C4, preferably C1 to C2 lower alkyl groups, and a methyl group is particularly preferable.

R12 represents an alkylene group. Examples of the alkylene group include C1 to C5, preferably C2 to C4, lower alkylene groups, and particularly preferably a propylene group.

R13 to R16 represent a monovalent hydrocarbon group,
Each may be the same or different. Examples of the monovalent hydrocarbon group include C1 to C4, preferably C1 to C2, lower alkyl groups and aryl groups such as phenyl groups;
-A halogenated alkyl group such as a trifluoropropyl group,
An alkenyl group such as a vinyl group and an allyl group can be exemplified, and it is particularly preferable that R13 to R16 are the same and that they are a methyl group.

R17 represents a monovalent hydrocarbon group, a hydroxyl group, and a compound represented by the general formula (4):

Embedded image Is a group selected from the group consisting of acrylic functional groups represented by

Examples of the monovalent hydrocarbon group include C1 to C4, preferably C1 to C2, lower alkyl groups. Particularly, a methyl group is preferable. In the above formula, R18 represents a hydrogen atom or an alkyl group. Examples of the alkyl group include C1 to C4, preferably C1 to C2 lower alkyl groups, and a methyl group is particularly preferable. R19 represents an alkylene group. As the alkylene group, C1 to C5, preferably C2 to C4
And a propylene group is particularly preferred.

M is an integer of 1 to 500, preferably 25 to
It is an integer of 300, more preferably 50 to 200.

In the polydiorganosiloxane macromer having an acrylic functional group, when R17 is a monovalent hydrocarbon group or a hydroxyl group in the general formula (3), the general formula (5):

Embedded image Using a lithium salt of an organosilane represented by the following formula as a polymerization initiator, general formula (6):

Embedded image Is obtained by non-equilibrium polymerization of a cyclic trisiloxane represented by the general formula (7):

Embedded image (R11 to R17 in the general formulas (5) to (7) are as defined above) (JP-A-2-9293).
No. 3).

On the other hand, when R17 is represented by the general formula (4), the general formula (8):

Embedded image With respect to 1 mol of the organopolysiloxane represented by the general formula (9):

Embedded image 1 mol of an organochlorosilane represented by the general formula (1)
0):

Embedded image (R11 to R16, R18, R19 and m in the general formulas (8) to (10) are as defined above) (see JP-A-58-167606). ).

The radically polymerizable organic monomer copolymerized with the polydiorganosiloxane macromer having an acrylic functional group is the same acrylic organic monomer as in the following general formula (2).

The silicone-modified acrylic resin used in the present invention is obtained by combining the above-mentioned polyorganosiloxane macromer (3) having an acrylic functional group and a radical polymerizable organic monomer (2) with azobisisobutyronitrile (AIB).
It can be obtained by copolymerizing in the presence of a radical polymerization initiator such as N).

At this time, the following general formula (11):

Embedded image It is preferable that the polyorganosiloxane represented by

In the above formula, R22 to R25 may be the same or different and represent a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include an alkenyl group such as a vinyl group and an allyl group; an aryl group such as a phenyl group; a halogenated alkyl group such as a 3,3,3-trifluoropropyl group;
4, preferably C1 to C2 lower alkyl groups. In particular, it is preferable that R22 to R25 are the same and are a methyl group. R26 and R27 each independently represent a monovalent hydrocarbon group or a hydroxyl group. Examples of the monovalent hydrocarbon group include C1 to C4, preferably C1 to C2, lower alkyl groups. It is particularly preferred that R26 and R27 are the same and are a methyl group.

N is 1 to 500, preferably 25 to 30
0, more preferably an integer of 50 to 200.

The polyorganosiloxane represented by the formula (11) is a well-known compound, and is an equilibrium polymerization reaction of a low-molecular-weight cyclic diorganopolysiloxane itself under an acid or alkali catalyst, or a reaction with a low-molecular-weight cyclic diorganopolysiloxane. It can be obtained by an equilibrium polymerization reaction with a low molecular weight linear diorganopolysiloxane under an acid or alkali catalyst. For example, in the case of polydimethylsiloxane, it is available as a commercial product as SH200 oil from Dow Corning Toray Silicone Co., Ltd.

When the polyorganosiloxane (11) is contained, the amount thereof is 1/8 to 1, preferably 1/4, based on the polydiorganopolysiloxane macromer (3).
１ ／. Finally, as the silicone-modified acrylic resin, in the presence or absence of the polydiorganosiloxane represented by the general formula (11), a polydiorganosiloxane having an acrylic functional group represented by the general formula (3) is used. It is a copolymer of an organosiloxane macromer and an acrylic organic monomer represented by the general formula (2).

Embedded image And a repeating unit (Mac) represented by

Embedded image The ratio (Mac / M) to the repeating unit (Msi) represented by
si) is in the range of 1/4 to 4/1. Further, the ratio is preferably in the range of 1/3 to 3/1, and particularly preferably, the ratio is in the range of 1/2 to 2/1.

If the ratio of Mac / Msi is less than 1/4, the productivity may be deteriorated. If the ratio is more than 4/1, toner components such as a charge controlling agent and a post-treatment agent adhere to the surface of the carrier. There is a possibility that the effect of preventing the problem cannot be sufficiently obtained.

The finally obtained silicone-modified acrylic resin is adjusted to have a softening point of 120 ° C. to 250 ° C. as physical properties.

The amino group-containing resin contained in the binder resin of the present invention has the following general formula (12):

Embedded image And a radical polymerizable styrene-based monomer such as styrene, butyl acrylate, butyl methacrylate, and methyl methacrylate. In the above formula, R30 represents a hydrogen atom, a lower alkyl group such as a methyl group or an ethyl group. R30 is preferably a methyl group. R31 and R32 each independently represent a lower alkyl group such as a methyl group, an ethyl group, and a propyl group. R31 and R32 are preferably a methyl group. n is an integer of 1 to 5, and preferably 2.

The amino group-containing resin used in the present invention is obtained by converting an amino group-containing monomer represented by the above general formula (12) and a styrene monomer into azobisisobutyronitrile (A
It can be obtained by copolymerizing in the presence of a radical polymerization initiator such as IBN). At that time, the amino group-containing resin finally obtained has an amine value of 0.3 to 0.3.
40 KOHmg / g, preferably 3 to 15 KOH / m
g, more preferably 5 to 10 KOH mg / g, having a softening point (Tm) of 120 ° C to 150 ° C, preferably 125 to 140 ° C, and a glass transition point (Tg) of 60 to 80 ° C. Preferably, the copolymerization ratio and the degree of polymerization are adjusted so as to have a temperature of 60 to 70 ° C. When the amine value is too small, the contribution to the improvement in the charge rising property is small, and when the amine value is too high, there is no difference in the contribution to the charge rising property.

The binder resin constituting the carrier of the present invention is prepared from a mixture of the above ethylenically unsaturated nitrile copolymer, a silicone-modified resin, an amino group-containing resin and, if desired, a mixture of other binder resins within a range not to impair the effects of the present invention. Become.

The ethylenically unsaturated nitrile copolymer is 5 to 95% by weight of the binder resin. If the amount is small, it causes a reduction in chargeability and environmental resistance, and also causes problems such as fogging. In particular, when the obtained carrier is used in combination with a negatively chargeable toner, a problem occurs in chargeability.
On the other hand, if the amount is too large, the durability deteriorates and the production becomes difficult.

When used in combination with a negatively chargeable toner, the amount of addition is preferably 20 to 80% by weight.

The silicone-modified acrylic resin accounts for 3 to 90% by weight, preferably 3 to 80% by weight of the binder resin. If the amount is small, the durability cannot be sufficiently improved, and toner fog and the like will occur. On the other hand, if the amount is too large, the binding property as a binder resin is deteriorated during the production of the carrier, causing a problem in the dispersibility of each component, making it difficult to melt and knead, thereby deteriorating the productivity. Further, even if it is manufactured by forcibly kneading, the carrier has poor binding properties and becomes a fragile carrier during use.

When used in combination with a negatively chargeable toner, the amount of addition is preferably 30 to 50%.

The content of the amino group-containing resin is 2 to 70% by weight, preferably 2 to 60% by weight. If the amount is too small, the contribution of the improvement to the charge rising property is reduced,
Fogging is likely to occur during high image density (B / W ratio) playback. Even if the amount is too large, there is no difference in the contribution to the charge build-up property, so that addition beyond a certain amount does not show improvement corresponding to the amount added.

When used in combination with a negatively chargeable toner, the amount of addition is preferably 5 to 60% by weight.

The binder resin constituting the carrier of the present invention may be, for example, a polyester resin, a styrene-acryl copolymer resin, a poly (meth) acryl resin, together with a silicone-modified acrylic resin and an amino group-containing resin.
A well-known resin generally used for a toner such as an epoxy resin may be used. Of these, poly (meth) acrylic resin is preferable because it can be suitably used for both positively and negatively chargeable toners. To set the positive or negative charge amount higher and more stably, when the carrier of the present invention is used in combination with a positively chargeable toner, polyester resin, epoxy resin, etc. It is preferable to use a styrene-acrylic copolymer resin or the like. Their addition amount is up to 95% by weight of the binder resin, preferably up to 70% by weight, more preferably up to 50% by weight. If the amount is too large, the copolymer resin containing the ethylenically unsaturated nitrile, the combination of the silicon-modified resin and the amino group-containing resin and the amount and ratio thereof, but the effects of the addition of those resins are reduced. Sisters,
In addition, problems such as fogging and scattering occur.

The carrier of the present invention is prepared, for example, by mixing the binder resin composed of each resin obtained above with a magnetic powder in a predetermined mixing ratio (100 to 900 parts by weight with respect to 100 parts by weight of the binder resin).
(By weight, preferably 300 to 700 parts by weight), a method of pulverizing and classifying after cooling, or a method of dissolving a binder resin in a solvent, dispersing magnetic powder in this resin solution, and then spray drying. By volume average particle size 2
It can be manufactured at 0 to 100 μm, preferably 30 to 80 μm.

The carrier has a saturation magnetization of 30 to 80 emu / g, preferably 35 to 65 emu / g.
g, more preferably 40 to 60 emu / g. This is because when the saturation magnetization of the carrier decreases, the magnetic restraining force of the carrier on the developer conveying member decreases, and the carrier easily adheres to the image carrier. Also, when the saturation magnetization of the carrier is high, the carrier is partially aggregated on the developer transport member, so that a uniform thin layer of the developer cannot be formed. This is because the reproducibility of images and high-definition images is reduced.

As the magnetic fine particles used for the carrier, for example, metals such as iron, nickel, and cobalt, ferrite, and magnetite can be used, and ferrite and magnetite are particularly preferable. The average particle size of these magnetic fine particles is desirably 5 μm or less, preferably 2 μm or less, and more preferably 0.1 to 1 μm from the viewpoint of uniform dispersion in the binder.

The carrier may contain a dispersant such as carbon black, silica, titania, and alumina. The uniform dispersibility of the magnetic powder in the binder resin can be improved by containing a dispersant.
The content of the dispersant is 0.01 to 3% by weight based on the carrier.
It is preferable that

The binder carrier of the present invention can be applied to both positively and negatively chargeable toners. It is desirable that the content of the toner with respect to the carrier in the present developer is 3 to 20% by weight, preferably 5 to 10% by weight.

When the content of the toner is less than 3% by weight, a sufficient image density cannot be obtained or the toner is excessively charged. When the content is more than 20% by weight, the toner is not sufficiently charged and the image is not sufficiently charged. This is because fogging is likely to occur on the surface.

[0055]

EXAMPLES The resins constituting the binder resin used in the production of the carrier are listed below. Ethylenic unsaturated nitrile copolymer: thermoplastic acrylonitrile-methyl acrylate-butadiene copolymer (acrylonitrile 65%, methyl acrylate 15%,
Butadiene 20%; MI value: 5.0) (hereinafter simply referred to as “acrylonitrile copolymer”). -Amino group-containing styrene acrylic resin, the following table:

[0056]

[Table 1]

In Table 1, the resin is represented by R3 in the general formula (12).
0, R31 and R32 are methyl groups and n is 2, and the resin is a resin wherein R30, R31 and R32 are methyl groups and n
Is 3, and the resins are R30, R31 and R32.
Is an ethyl group and n is 2).・ Silicone-modified acrylic resin: (Softening point 200 ° C; D
CTS).

The above silicone-modified acrylic resin is

Embedded image Is reacted by reacting with
ac / Msi is 1/1.

(Example of Production of Carrier A) Acrylonitrile copolymer 50 parts by weight Silicone-modified acrylic resin 20 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 1 part by weight Amino group-containing styrene acrylic resin 30 parts by weight

After sufficiently mixing the above materials with a Henschel mixer, a vent twin screw extruder (PCM-30:
(Ikegai Iron Works, Ltd.) at 200 ° C. The kneaded material is roughly pulverized by a feather mill, then finely pulverized by a jet pulverizer (IDS-2: manufactured by Nippon Pneumatic Industries, Ltd.), and then pulverized by an air classifier (MS-1: manufactured by Hosokawa Micron). Classified. The classified material was subjected to a heat treatment at 300 ° C. by using a suffusing system (SFS-2: manufactured by Nippon Pneumatic Industries, Ltd.) to obtain a carrier having a volume average particle size of 50 μm. The obtained carrier is referred to as carrier A.

(Production Example of Carrier B) Acrylonitrile copolymer 80 parts by weight Silicone-modified acrylic resin 10 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (REGAL330: manufactured by Cabot) 2 parts by weight Part Amino group-containing styrene acrylic resin 10 parts by weight A carrier having a volume average particle size of 50 μm was obtained in the same manner as in the production method of carrier A using the above materials. The obtained carrier is referred to as carrier B.

(Production Example of Carrier C) Acrylonitrile copolymer 40 parts by weight Silicone-modified acrylic resin 30 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 parts by weight Amino group-containing styrene acrylic resin 30 parts by weight A carrier having a volume average particle size of 55 μm was obtained using the above-mentioned materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier C.

(Production of Carrier D) Acrylonitrile copolymer 50 parts by weight Silicone-modified acrylic resin 40 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 Parts by weight Amino group-containing styrene acrylic resin 10 parts by weight A carrier having a volume average particle size of 50 μm was obtained in the same manner as in the production method of Carrier A using the above materials. The obtained carrier is referred to as carrier D.

(Production of Carrier E) Acrylonitrile copolymer 20 parts by weight Silicone-modified acrylic resin 70 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 550 parts by weight Carbon black (REGAL330: manufactured by Cabot) 1 part by weight Amino group-containing styrene acrylic resin 10 parts by weight A carrier having a volume average particle size of 55 μm was obtained using the above materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier E.

(Production of Carrier F) Acrylonitrile copolymer 30 parts by weight Silicone-modified acrylic resin 10 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 550 parts by weight Carbon black (REGAL330: manufactured by Cabot Corporation) 2 parts by weight Part Amino group-containing styrene acrylic resin 60 parts by weight A carrier having a volume average particle size of 55 μm was obtained in the same manner as in the production method of carrier A using the above materials. The obtained carrier is referred to as carrier F.

(Production of Carrier G) Acrylonitrile copolymer 50 parts by weight Silicone-modified acrylic resin 10 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (Ketjen Black EC: Lion Oil & Fats Co., Ltd.) 1 part by weight Amino group-containing styrene acrylic resin 40 parts by weight A carrier having a volume average particle diameter of 50 μm was obtained using the above-mentioned materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier G.

(Manufacture of Carrier H) Acrylonitrile copolymer 10 parts by weight Silicone modified acrylic resin 40 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 Parts by weight Amino group-containing styrene acrylic resin 50 parts by weight A carrier having a volume average particle size of 50 μm was obtained using the above-mentioned materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier H.

(Manufacture of Carrier I) Acrylonitrile copolymer 10 parts by weight Silicone-modified acrylic resin 30 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 Parts by weight Amino group-containing styrene acrylic resin 60 parts by weight A carrier having a volume average particle size of 50 μm was obtained using the above materials in the same manner as in the production method of Carrier A. The obtained carrier is referred to as carrier I.

(Manufacture of Carrier J) Acrylonitrile copolymer 10 parts by weight Silicone modified acrylic resin 25 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 By weight Amino group-containing styrene acrylic resin 25 parts by weight Thermoplastic polyester resin (Tm: 120 ° C., Tg: 65 ° C.) 40 parts by weight Using the above-mentioned materials, the volume average particle diameter is 50 μm in the same manner as in the production method of carrier A. Got a career. The obtained carrier is referred to as carrier J.

(Production of Carrier K) 100 parts by weight of thermoplastic polyester resin (Tm: 120 ° C., Tg: 65 ° C.) 500 parts by weight of ferrite magnetic powder (MFP-2: manufactured by TDK Corporation) carbon black (# 970: Mitsubishi Chemical Corporation) 2 parts by weight A carrier having a volume average particle size of 50 μm was obtained using the above materials in the same manner as in the method for producing the carrier A. The obtained carrier is referred to as carrier K.

(Production of Carrier L) Acrylonitrile copolymer 60 parts by weight Silicone-modified acrylic resin 40 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 Parts by weight Using the above materials, a carrier having a volume average particle diameter of 50 μm was obtained in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier L.

(Production of Carrier M) Acrylonitrile copolymer 70 parts by weight Amino group-containing styrene acrylic resin 30 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 550 parts by weight Carbon black (REGAL330: manufactured by Cabot) 2 Parts by weight Using the above materials, a carrier having a volume average particle diameter of 50 μm was obtained in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier M.

(Production of Carrier N) Silicone-modified acrylic resin 45 parts by weight Amino group-containing styrene acrylic resin 55 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (REGAL330: manufactured by Cabot Corporation) 2 parts by weight Using the above materials, a carrier having a volume average particle size of 55 μm was obtained in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier N.

(Production Example of Carrier O) Acrylonitrile copolymer 20 parts by weight Silicone-modified acrylic resin 80 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 parts by weight Using the above-mentioned materials, an attempt was made to prepare a carrier O in the same manner as in the production method of the carrier A, but the kneading could not be carried out sufficiently, and no usable carrier could be obtained.

(Production of Carrier P) Acrylonitrile copolymer 5 parts by weight Silicone-modified acrylic resin 45 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 3 Parts by weight Amino group-containing styrene acrylic resin 50 parts by weight A carrier having a volume average particle size of 50 μm was obtained using the above-mentioned materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier P.

(Production of Carrier Q) Acrylonitrile copolymer 95 parts by weight Silicone-modified acrylic resin 3 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 Parts by weight Amino group-containing styrene acrylic resin 2 parts by weight A carrier having a volume average particle size of 50 μm was obtained in the same manner as in the production method of Carrier A using the above materials. The obtained carrier is referred to as carrier Q.

(Production of Carrier R) Acrylonitrile copolymer 80 parts by weight Silicone-modified acrylic resin 5 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (REGAL330: manufactured by Cabot Corporation) 2 parts by weight Part Amino group-containing styrene acrylic resin 15 parts by weight A carrier having a volume average particle size of 55 μm was obtained in the same manner as in the production method of carrier A using the above materials. The obtained carrier is referred to as carrier R.

(Production of Carrier S) Acrylonitrile copolymer 10 parts by weight Silicone-modified acrylic resin 80 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 2 parts by weight Amino group-containing styrene acrylic resin 10 parts by weight A carrier having a volume average particle diameter of 50 μm was obtained using the above-mentioned materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier S.

(Manufacture of Carrier T) Acrylonitrile copolymer 50 parts by weight Silicone-modified acrylic resin 47 parts by weight Magnetite fine powder (RB-BL: manufactured by Titanium Industry Co., Ltd.) 500 parts by weight Carbon black (REGAL330: manufactured by Cabot Corporation) 2 parts by weight Part Amino group-containing styrene acrylic resin 3 parts by weight A carrier having a volume average particle size of 55 μm was obtained using the above materials in the same manner as in the method for producing carrier A. The obtained carrier is referred to as carrier T.

(Production of Carrier U) Acrylonitrile copolymer 20 parts by weight Silicone-modified acrylic resin 10 parts by weight Ferrite magnetic powder (MFP-2: manufactured by TDK) 500 parts by weight Carbon black (# 970: manufactured by Mitsubishi Chemical Corporation) 3 Parts by weight Amino group-containing styrene acrylic resin 70 parts by weight A carrier having a volume average particle diameter of 50 μm was obtained using the above materials in the same manner as in the production method of Carrier A. The obtained carrier is referred to as carrier U.

The average particle size of the carrier was measured using a Coulter Multisizer (manufactured by Coulter Inc.).
The relative weight distribution by particle size was measured with an 0 μm aperture tube.

Production of Toner a Thermoplastic polyester resin (softening point 120 ° C., glass point transition 61 ° C.) 100 parts by weight Carbon black (Mogal L: manufactured by Cabot) 8 parts by weight Low molecular weight propylene (Biscol 550P: Sanyo Chemical Industries, Ltd.) 3 parts by weight Negative charge control agent (Bontron S-34: manufactured by Orient Chemical Industries) 5 parts by weight

After sufficiently mixing the above components, the mixture was melted and kneaded at 140 ° C. using a vented biaxial kneader, and the kneaded product was cooled. After cooling, the kneaded material was coarsely pulverized with a feather mill, further finely pulverized with a jet pulverizer, and then subjected to air classification to obtain a black fine powder having a volume average particle diameter of 9 μm. 100 parts by weight of this black fine powder was treated with a hydrophobic silicide (H-200).
0: manufactured by Hoechst Javan Co., Ltd.) and treated with a Henschel mixer (manufactured by Mitsui Miike Kakoki Co., Ltd.) at 1000 rpm for 1 minute to obtain a negatively chargeable toner. The toner obtained here is referred to as a toner a.

Preparation of Toner b Polyester resin (softening point 100 ° C., glass transition point 58)
C.) and a magenta pigment (CI Pigment Red 18)
4) was charged and kneaded in a pressure kneader so that the weight ratio of resin: pigment was 7: 3. The obtained kneaded material was cooled and pulverized by a feather mill to obtain a pigment master batch.

[0085] 93 parts by weight of the polyester resin, 10 parts by weight of the master batch, and a zinc salicylate complex (E
-84: Orient Chemical Industries, Ltd.) 2 parts by weight of toner a
A fine powder having a volume average particle size of 8.5 μm was obtained in the same manner as in the production of. To 100 parts by weight of this black fine powder, 0.5 parts by weight of hydrophobic silicide (H-2000: manufactured by Hoechst Japan) and 0.6 parts by weight of titanium oxide fine particles (STT-30A; manufactured by Titanium Co., Ltd.) are added. And a Hensiel mixer at 1000 rpm for 1 minute to obtain a magenta toner. The obtained result is referred to as a toner b.

The average particle size of the toner was measured using a Coulter Multisizer (manufactured by Coulter Inc.).
The relative weight distribution by particle size was measured using a μm aperture tube.

Examples 1 to 16 and Comparative Examples 1 to 6 The carriers A to U (excluding the carrier O) and the toners a and b obtained above were used in combination as shown in Table 1 below. , Toner (T) and carrier (C) ratio (T
(/ C ratio) 6% by weight was used to prepare a developer used in Examples and Comparative Examples.

[0088]

[Table 2]

Evaluation 1 (fog) Examples 1, 2, 5, 6 and 9 to 10, and Comparative Example 3
To 4 were mixed for 1 hour using a roll mill. This developer was loaded into a copying machine Di-30 manufactured by Minolta Co., and a B / W ratio of 1 under an N / N environment (25 ° C., 50%).
300,000 prints of 0% and 50% images were printed each time. Initially, 20,000 (20K), 50,000 (50K), and 70,000 (70K)
0K), 100,000 sheets (100K), 150,000 sheets (150
K), 200,000 sheets (200K), 250,000 sheets (250K), and 300,000 sheets (300K) were visually evaluated for fog on a blank image. The evaluation was ranked as follows.

A: Rank 5: No fog at all;: Ranks 3 and 4: Not noticeable by visual observation, but confirmed with a microscope or the like; Δ: Rank 2: Slightly confirmed by visual observation; The results are shown in Table 3 below.

[0091]

[Table 3]

Similarly, an H / H environment (30 ° C., 80
%) And under L / L environment (10 ° C., 10%), 300,000 images of B / W ratio of 10% were printed, respectively, at the stage of 200,000 sheets (200K) and 300,000 sheets (300K). The fog was evaluated in the same manner as described above. The results are shown in Table 4.

[0093]

[Table 4]

Evaluation 2 (fog) Examples 3, 4, 7, 8, 11 to 16 and Comparative Examples 1 and 2
Was mixed using a roll mill for 1 hour. This developer was loaded into a copying machine CF-70 manufactured by Minolta Co., and a B / W ratio of 10 under an N / N environment (25 ° C., 50%).
% And 50% of the images were printed on 150,000 sheets, respectively, and the initial printing was 10,000 sheets (10K), 20,000 sheets (20K), 30,000 sheets (3K).
0K), 50,000 sheets (50K), 70,000 sheets (70K), 10
Fog on a blank image at the stage of 10,000 sheets (100K) and 150,000 sheets (150K) was visually evaluated. The evaluation was performed in the same manner as described above. The results are shown in Table 5 below.

[0095]

[Table 5]

Similarly, an H / H environment (30 ° C., 80
%) And an image having a B / W ratio of 10% under an L / L environment (10 ° C., 10%) was printed for 150,000 sheets, and was printed at 100,000 sheets (100K) and 150,000 sheets (150K). The fog was evaluated in the same manner as described above. The results are shown in Table 6.

[0097]

[Table 6]

Evaluation 3 (Image density unevenness) Examples 1, 2, 5, 6, and 9 to 10, and Comparative Example 3
To 4 were mixed for 1 hour using a roll mill. This developer was loaded into a copying machine Di-30 manufactured by Minolta Co., and a B / W ratio of 1 under an N / N environment (25 ° C., 50%).
300% of each 0% of the images are printed, 20,000 (20K), 50,000 (50K), 70,000 (70K),
The image density unevenness at the stage of 100,000 sheets (100K), 150,000 sheets (150K), 200,000 sheets (200K), 250,000 sheets (250K) and 300,000 sheets (300K) was visually evaluated. The evaluation was ranked as follows.

◎: Rank 5: No fog at all;: Ranks 3 and 4: Not noticeable by visual observation, but confirmed by microscope, etc .; Δ: Rank 2: Slightly confirmed by visual observation; ×: Rank 1: Overall The results are shown in Table 7 below.

[0100]

[Table 7]

Similarly, an H / H environment (30 ° C., 80
%) And under L / L environment (10 ° C., 10%), 300,000 images of B / W ratio of 10% were printed, respectively, at the stage of 200,000 sheets (200K) and 300,000 sheets (300K). The image density unevenness was evaluated in the same manner as described above. The results are shown in Table 8.

[Table 8]

Evaluation 4 (Image density unevenness) Examples 3, 4, 7, 8, 11 to 16 and Comparative Examples 1 and 2
Was mixed using a roll mill for 1 hour. This developer was loaded into a copying machine CF-70 manufactured by Minolta Co., and a B / W ratio of 10 under an N / N environment (25 ° C., 50%).
% Of the images were printed for 150,000 copies each, and the initial 10,000 copies (1
0K), 20,000 sheets (20K), 30,000 sheets (30K), 50,000 sheets (50K), 70,000 sheets (70K), 100,000 sheets (100K)
K), and image density unevenness at the stage of 150,000 sheets (150K) was visually evaluated. The evaluation was performed in the same manner as described above. The results are shown in Table 9 below.

[0103]

[Table 9]

Similarly, an H / H environment (30 ° C., 80
%) And an image having a B / W ratio of 10% under an L / L environment (10 ° C., 10%) was printed for 150,000 sheets, and was printed at 100,000 sheets (100K) and 150,000 sheets (150K). The image density unevenness was evaluated in the same manner as described above. The results are shown in Table 10.

[0105]

[Table 10]

[0106]

According to the present invention, there is provided a carrier which is excellent in charge stability even when used for a long period of time and does not cause problems such as fog and uneven image density.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoharu Nishikawa 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Hideaki Yasunaga Azuchi-cho, Chuo-ku, Osaka-shi, Osaka 2-3-13, Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroyuki Fukuda 2-3-113, Azuchicho, Chuo-ku, Osaka City, Osaka Inside Osaka International Building Minolta Co., Ltd.

Claims (4)

[Claims] 1. A binder carrier comprising at least a magnetic powder and a binder resin, wherein the binder resin contains at least a copolymer containing an ethylenically unsaturated nitrile, a silicone-modified acrylic resin, and an amino group-containing resin. Binder carrier. 2. The binder carrier according to claim 1, wherein the ethylenically unsaturated nitrile copolymer contains 5 to 95% by weight of the binder resin. 3. The binder carrier according to claim 1, wherein the silicone-modified acrylic resin contains 3 to 90% by weight of the binder resin. 4. An amino group-containing resin is a binder resin.
2. The composition according to claim 1, wherein the content is about 70% by weight.
4. The binder carrier according to any one of claims 1 to 3.