JPH0627729A - Developer and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a developer without deteriorating its productivity, which is improved as to fluctuation in specific charge so as to be capable of stably keeping an amount of electrification throughout its life and from the initial stage of use and which is improved also in fluidity so as to be capable of maintaining high picture quality over a long period of time without causing blocking, so providing image density stability in particular. CONSTITUTION:A method of manufacture of a developer comprises admixing a carrier with inorganic particles, attaching the inorganic particles thereby to the surface of the carrier, and electrostatically mixing and attaching a toner to the carrier surface; the main component of the binding resin of the toner is a polyester resin with a value of OHV/AV being 1.2 or more, AV and OHV being the acid number and the hydroxyl group number of the resin, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component dry developer composed of a toner and a carrier, which is used in electrophotography, electrostatic recording, electrostatic printing, etc., and a method for producing the same. The present invention relates to a developer in which a powder of magnetic particles and a powder of inorganic fine particles for surface treatment are mixed and adhered, and then a toner is added and adhered, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, US Pat. Nos. 2,221,776 and 22 are known as electrophotographic methods.
As described in the specification of No. 97691, No. 2357809, etc., the photoconductive insulating layer is uniformly charged (charging step), and then the layer is exposed (exposure step) to charge the exposed portion. To form an electrostatic latent image, which is then visualized (development step) by attaching colored charged fine powder called toner to the electrostatic latent image. After the image is transferred to a transfer material such as transfer paper (transfer process), it is permanently fixed by heating, pressure or other appropriate means (fixing process)
A method of steps has been practiced.

The developing methods applied to these electrophotographic methods are roughly classified into a dry developing method and a wet developing method.
The former further includes a method using a one-component developer and a method using a two-component developer, and the present invention relates to a method for producing a two-component dry developer. Among the methods using a two-component dry developer, there are a magnetic brush developing method using a magnetic powder carrier, a cascade developing method using a somewhat coarse bead carrier, etc., depending on the type of a toner conveying system. When a color developer is used, basically, the electrophotographic method described above is repeated to repeat the steps of [charging] → [exposure] → [development] → [transfer] a plurality of times, and then the color image is formed by fixing. Done. However, in the exposure step, it is different in that it is exposed by a color separation filter or by writing an image read by a scanner with a laser or the like.

As the toner applied to these developing methods, fine powders in which a coloring agent such as a dye or a pigment is dispersed in a natural or synthetic thermoplastic resin have been generally used. As the synthetic resin type, for example, a binder resin such as a styrene-acrylic copolymer type (polystyrene type) resin, a polyester type resin, an epoxy type resin or the like is mixed with various functional additives such as a colorant, a charge control agent and a wax. Particles obtained by pulverizing the dispersed material to about 1 to 30 μm are used as the toner. A two-component developer composed of such a toner and a carrier is generally required to have long life, that is, stability and maintainability of image quality in continuous development. For that purpose, the charge amount between the toner and the carrier particles and the resistance of the developer must be maintained within an appropriate range, and it is most preferable that the initial charge amount does not change even in the latter half of the long run.

For the purpose of stably maintaining the charge amount and resistance of these developers, the design and selection of a binder resin, a charge control agent and other additives have been studied from the toner side. On the other hand, from the carrier side, various studies have been made on the oxidation treatment method of iron powder, the constituent materials such as ferrite and magnetite, the surface shape of the magnetic powder, the surface coating material and the treatment method thereof. Recently, for example, as a surface coating method for a carrier, a carrier surface-coated by a solution method (JP-A-62-806).
69) and by the dry method (Japanese Patent Laid-Open No. 62-235).
No. 959) has been proposed for the purpose of maintaining the triboelectric charging ability of toner for a long period of time. However, all of these technologies are related to long-life property, that is, stability improvement of image quality in long-term continuous development, and to improve initial charge fluctuation and resistance fluctuation at the start of use of the developer, It does not improve the stability of the fluidity of the agent.

That is, when a developer prepared by mixing a toner and a carrier is set in a developing unit of a printer or a copying machine and the actual development is started, within a few minutes after the start of use, It is pointed out that the change of the carrier particle surface after 100 times of development causes a rapid change of the charge amount level of the developer called "initial life charge fluctuation", and the undesired change of the developer resistance and the image quality accompanying it. Has been done. Because of this,
An improved method has been proposed by pre-preparing carrier particles prior to making the developer (US Pat. No. 3,9,9).
70,571). That is, before the toner and the carrier are mixed and stirred to produce the developer, the carrier particles are previously stirred and mixed with the toner for pre-preparation including the charge control agent and the binder resin, and the carrier surface of the toner at the initial stage of the developer is used. This is a method of intentionally causing pore filling, scumming and abrasion of the carrier surface, then removing excess pre-preparation toner, and then mixing with the toner to produce a developer. A developer produced through such preliminary preparation of carrier particles is expected to have an effect of reducing "variation in initial life charge".

However, in this technique, although the change in initial life charge can be reduced, the carrier coating agent is peeled off more than necessary during preliminary preparation, which conversely reduces long-life property. There were major problems such as the need to manufacture toners having different particle size distributions for preparation, and the fact that the pre-preparation time took several hours, resulting in a significant decrease in developer productivity. . Furthermore, a method has also been proposed in which the charge amount of the developer is stably maintained over the life of the developer without requiring such a mechanical preconditioning treatment of the developer carrier (US Pat. No. 4, 828,956 specification). However, in this method, two types of toners, the first developer toner and the second developer toner, must be manufactured separately, and when the frictional charge product of each developer is measured, It cannot be said that the manufacturing problem has been solved because the correlation is unknown.

On the other hand, in addition to the above-mentioned proposals for improving the charging characteristics, there have been many proposals for improving the toner for the purpose of improving the fixing property. For example, Japanese Patent Laid-Open No. Sho 62
No. 195676, No. 62-195677, No. 62-195678, No. 62-1
In Japanese Patent Laid-Open No. 95679 and Japanese Patent Laid-Open No. 62-195680, the main component of the binder resin of the toner is that the acid value of the resin is A
A developer having excellent low-temperature fixability has been proposed by using a polyester resin having an OHV / AV value of 1.2 or more where V and a hydroxyl value are OHV. Such a toner has a low molecular weight component because the molecular weight distribution of the resin is widened in order to secure a wide offset range and low temperature fixability. Then, this low molecular weight component is spent on the carrier surface during continuous use at high temperature and high humidity due to heat and pressure generated by repeating development a plurality of times over a long period of time (fusing to form a layer of low molecular weight component). However, there is a problem in that the carrier is firmly adhered in the form in which the toner is caught between the spent portions, and blocking of the developer is caused.

The present invention has been made in view of the above circumstances, and its object is to reduce the charge amount and the charge amount of the developer without deteriorating the productivity of the developer even when a toner excellent in low temperature fixing property is used. It is an object of the present invention to provide a developer whose fluidity can be stably maintained from the time of initial use throughout the life of the developer and a method for producing the same.

[0010]

[Means for Solving the Problems] The inventors of the present invention have conducted various studies for the purpose of solving the above-mentioned problems, and after mixing and adhering inorganic fine particles on the surface of a carrier, toner is added to the surface of the carrier to electrostatically charge it. By mixing and adhering it to produce the developer, even when the developer is used in an actual machine such as a printer or a copying machine, the initial charge fluctuation is not recognized, and the productivity of the developer is not significantly impaired. It was found that the property can be secured, and further research was conducted to complete the present invention.

That is, the gist of the present invention is (1) a developer in which a carrier and inorganic fine particles are mixed to adhere the inorganic fine particles to the carrier surface, and then the toner is electrostatically mixed and adhered to the carrier surface. A manufacturing method, wherein the main component of the binder resin of the toner is a polyester resin having an OHV / AV value of 1.2 or more when the resin has an acid value of AV and a hydroxyl value of OHV. And (2) a developer comprising a carrier in which inorganic particles are adhered to the surface of a carrier and a toner, the main component of the binder resin of the toner is the acid value of the resin is AV, When the hydroxyl value is OHV, OHV / A
The present invention relates to a developer having a V value of 1.2 or more and containing 1 to 15 parts by weight of the toner with respect to 100 parts by weight of a carrier.

In the manufacturing method of the present invention, first, the inorganic fine particles are attached to the surface of the carrier by mixing the carrier and the inorganic fine particles. As the inorganic fine particles used for the treatment of the surface of the carrier, it is possible to use all those which have been conventionally known to be used for electrophotography.

Concretely, for example, silica, alumina, titanium oxide and tin oxide, and the surface of which is made conductive with antimony, barium titanate,
Magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, Examples thereof include barium carbonate, calcium carbonate, silicon carbide and silicon nitride. In particular, even in the case of silica, it is preferable that the silanol groups on the surface are hydrophobized with hexamethyldisilazane or dimethyldichlorosilane.

The particle size of these inorganic fine particles depends on the carrier and the particle size of the toner to be used and cannot be specified unconditionally. However, it is generally 1 of the average particle size of the toner used.
It is possible to use one that is one-tenth or less. More preferably, those having a primary average particle diameter of 1 / 10,000 to 1/100 are more effective. If the average particle size is larger than 1/10 of the toner particle size, the surface of the photosensitive member tends to be damaged, and if the average particle size is smaller than 1 / 10,000, the particles are easily scattered and are difficult to handle.
Specifically, the average primary particle diameter of the inorganic fine particles is usually 0.0
01-0.1 μm, preferably 0.005-0.05 μ
m is used. In the present invention, the above inorganic fine particles may be the same as or different from those used for the surface treatment of the toner described below. Also,
These may be used alone or in combination of two or more.

The carrier used in the present invention can be selected from various porous or non-porous materials and is usually 20 to 500 μm, preferably 55 to 16 μm.
Those having an average particle size of 0 μm are used. Specifically, for example, glass beads, inorganic salt crystals, hard resin particles, metal fine particles and the like are used. Further, magnetic carrier particles can be used in the present invention, and examples thereof include iron powder, nickel powder, and ferrite powder. The surfaces of these magnetic carrier particles are styrene acrylic resin, polyester resin, silicone resin, silicone acrylic resin, or various fluorocarbons such as fluorocarbon resin, such as kiner, polytetrafluoroethylene, polyvinylidene fluoride, vinyl fluoride and tetrafluorocarbon. It may be coated with a resin containing a fluoroethylene copolymer or a mixture thereof.

In the present invention, when the inorganic fine particles are mixed and adhered to these carriers, the addition amount of the inorganic fine particles is
It cannot be unconditionally specified because it depends on the mixing device or the mixing conditions, but it is within the range that it is possible to sufficiently suppress the electrostatic fluctuation in the initial stage of printing durability use and to not cause the problem such as black spots. It is necessary and usually 0.001 to 0.5 part by weight, preferably 0.005 to 0.3 part by weight, is used per 100 parts by weight of the carrier. In this case, if the addition amount is less than 0.001 part by weight, the effect of coating or scumming on the surface of the carrier or the pores is small, and the effect effective in reducing the initial change in the charge amount cannot be obtained, which is not preferable. On the other hand, if the amount added exceeds 0.5 part by weight, the amount of free inorganic fine particles increases, and the inorganic fine particles move to the surface of the toner and the chargeability of the toner is changed, or secondary aggregates thereof are generated, resulting in a photoreceptor. It is not preferable because it may cause scratches that become the core of black spots.

Here, the black spot is a kind of filming on the photoconductor and appears as a black spot on the visible image. This is remarkable when the inorganic fine particles are considerably hard, so that it is remarkable when the photoconductor has a relatively small hardness such as a selenium-tellurium-based material or an organic photoconductor, and further, it is considered to be relatively hard. However, the same problem occurs in the case of using a selenium-arsenic material which is fragile against mechanical impact.

The apparatus used for mixing is not particularly limited, and is generally used, for example, horizontal cylindrical type, V type, W type container rotary type mixer, Nauta mixer, container mixer and the like. A mixing device is used. Among the above-mentioned mixing devices, for example, when a container rotary mixer is used, the peripheral speed of rotation in mixing the carrier and the inorganic fine particles is 20 to 100 m / m depending on their mixing volume.
It is preferably in the range of minutes. If the rotational peripheral speed exceeds 100 m / min, the mixing effect becomes unnecessarily large, wear of the carrier surface and reaggregation of the inorganic fine particles proceed undesirably. On the other hand, when the rotation peripheral speed is lower than 20 m / min, the inorganic fine particles are not evenly adhered to the carrier surface, and the effect of the adhesion becomes small.

In the method for producing a developer of the present invention, the surface of the carrier is treated with the inorganic fine particles as described above. In the present invention, the toner thus treated is further electrostatically mixed with the toner. Attach it. The method of mixing and adhering the toner may be any method used in the preparation of an ordinary two-component developer, and examples thereof include the same method as in the case of the treatment of the carrier surface described above. In this case, the above-mentioned mixing device or the like can be used. Also,
The mixing conditions using these mixing devices are not particularly limited, and may be ordinary conditions. At this time, the addition amount of the toner is usually 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the carrier.

The toner is generally composed of a binder resin and additives such as a charge control agent, a colorant, a fluidity improver, a cleaning improver and a release agent. The toner used in the present invention is If the acid value of the resin is AV and the hydroxyl value is OHV, the main component of the binder resin of the toner is OHV / AV
The toner is a polyester resin having a value of 1.2 or more. The particle size of the toner is usually 6 to 15 μm, preferably 8 to 13 μm, though it depends on the size of the carrier particles. The toner used in the present invention may have either a positive charging property or a negative charging property, but from the viewpoint of the negative charging property of the polyester resin itself, the negative charging property is particularly preferable.

The toner used in the present invention has a wide offset range and low-temperature fixability because it contains the above polyester resin. The polyester resin contains the following alcohol component and carboxylic acid, carboxylic acid ester, Alternatively, it is obtained by polycondensation with a carboxylic acid anhydride.

Examples of the alcohol component include (a) a diol component represented by the general formula (I).

[0023]

[Chemical 1]

(Wherein R is an ethylene or propylene group,
x and y are each an integer of 1 or more, and the average value of x + y is 2 to 7. )

Specifically, for example, polyoxypropylene
(2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.
0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene
(2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and the like can be mentioned.

Also optionally other diols such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4- Butenediol, 1,5-pentanediol, 1,6-hexanediol, and other diols, bisphenol A, hydrogenated bisphenol A, and other dihydric alcohols alone or in the general formula shown in (a). It is used in combination with the diol component represented by (I).

(B) Examples of the divalent carboxylic acid, carboxylic acid ester or carboxylic acid anhydride include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid and cyclohexane. Examples thereof include dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid and malonic acid, and further n-butylsuccinic acid, n-butenylsuccinic acid, isobutylsuccinic acid, isobutenylsuccinic acid, n-octylsuccinic acid, n. -Octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid,
Examples thereof include alkyl or alkenyl succinic acids such as isododecenyl succinic acid, other divalent carboxylic acids, anhydrides of these acids, and lower alkyl esters.

(C) For trivalent or higher valent compounds, among the trivalent or higher valent polyfunctional monomers, alcohol components include, for example, sorbitol, 1,2,3,6-hexanetetrol, 1,
4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,
Examples thereof include 2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene and other trihydric or higher alcohols. Examples of trivalent or higher carboxylic acid components include 1,2,4
-Benzenetricarboxylic 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-octanetetracarboxylic acid Examples thereof include acids, enpol trimer acids, other trivalent or higher carboxylic acids, their anhydrides and lower alkyl esters.

Further, the polycarboxylic acid may also be a tetracarboxylic acid represented by the following formula.

[0030]

[Chemical 2]

(In the formula, X is an alkylene group having 5 to 30 carbon atoms or an alkenylene group having at least one side chain having 3 or more carbon atoms.) Specifically, in the following (1) to (12) Examples include those shown. (1) 4-Neopentylidene-1,2,6,7-heptanetetracarboxylic acid (2) 4-Neopentyl-1,2,6,7-heptene (4) -tetracarboxylic acid (3) 3- Methyl-4-heptenyl-1,2,5,6-hexanetetracarboxylic acid (4) 3-methyl-3-heptyl-5-methyl-1,2,6,7
-Heptene (4) -Tetracarboxylic acid (5) 3-nonyl-4-methylidenyl-1,2,5,6-hexanetetracarboxylic acid (6) 3-decyridenyl-1,2,5,6-hexanetetracarboxylic acid Acid (7) 3-nonyl-1,2,6,7-heptene (4) -tetracarboxylic acid (8) 3-decenyl-1,2,5,6-hexanetetracarboxylic acid (9) 3-butyl- 3-Ethylenyl-1,2,5,6-hexanetetracarboxylic acid (10) 3-methyl-4-butyridenyl-1,2,6,7-heptanetetracarboxylic acid (11) 3-methyl-4-butyl- 1,2,6,7-heptene (4)
-Tetracarboxylic acid (12) 3-methyl-5-octyl-1,2,6,7-heptene
(4) -Tetracarboxylic acid

The polyester resin in the present invention comprises a diol component as shown in (a) above, a divalent carboxylic acid, a carboxylic acid ester or a carboxylic acid anhydride as shown in (b) above, and It can be obtained by copolycondensing a trivalent or higher carboxylic acid component and a polyhydric alcohol component as shown in (4). Specifically, according to a commonly used known method, for example, in an inert gas atmosphere, 180 ~
It can be produced by polycondensation at a temperature of 250 ° C. At this time, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide,
Dibutyltin oxide, dibutyltin dilaurate, etc. can be used. Further, for the same purpose, it can be produced under reduced pressure.

Specific examples of the polyester resin thus produced include the following. 1) Polyester resin (1) A polyester resin having an ethyl acetate insoluble content of 3.0% by weight or more (JP-A-62-195676).

2) Polyester resin (2) The diol component of (a) above, the divalent carboxylic acid or its acid anhydride or its lower alkyl ester described in (b) above, and the above (c) above. A polyester resin copolycondensed with a carboxylic acid having a valence of 3 or more, an acid anhydride thereof, a lower alkyl ester thereof, or a polyhydric alcohol having a valence of 3 or more (JP-A-62-195677).

3) Polyester resin (3) The diol component of the above (a) and the divalent carboxylic acid described in the above (b) are alkyl or alkenyl succinic acid in an amount of 5 to 50 in the total carboxylic acid component.
A divalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof, which is contained in a mol%, and a trivalent or higher polyvalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof in the above (c).
Alternatively, a polyester resin copolycondensed with a trihydric or higher polyhydric alcohol (JP-A-62-195678).

4) Polyester resin (4) Among the divalent carboxylic acids described in (b) above, the alkyl or alkenyl succinic acid in the diol component of (a) above is used in an amount of 5 to 50 in all carboxylic acid components.
A divalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof contained in an amount of mol%, and the following formula in (C) above:

[0037]

[Chemical 3]

(In the formula, X is an alkylene group having 5 to 30 carbon atoms or an alkenylene group having at least one side chain having 3 or more carbon atoms.), A tetracarboxylic acid represented by the formula, an acid anhydride thereof, or a derivative thereof. Polyester resin copolycondensed with trivalent or higher polyvalent carboxylic acid containing 0.1 to 20 mol% of lower alkyl ester in all carboxylic acid components, or acid anhydride thereof or lower alkyl ester thereof (JP-A-62-195679). Gazette).

5) Polyester resin (5) The diol component of (a) above, the divalent carboxylic acid described in (b) above, its acid anhydride or its lower alkyl ester, and three of the above (c) above. Polyester resin obtained by copolycondensation of polyhydric alcohol having a valency of 3 or more and polyhydric carboxylic acid having a valency of 3 or more or an acid anhydride thereof or a lower alkyl ester thereof described in (C) (JP-A-62-195680). ).

As the polyester resin in the present invention, polyester resins (1) to (5) having an OHV / AV value of 1.2 or more are used. AV, OHV
Is measured by the method specified in JIS K 0070. In this case, when the ethyl acetate insoluble content is 3.0% by weight or more, it is desirable to use dioxane as the acid value measuring solvent. OHV
A value of / AV of 1.2 or more can be easily obtained by using a larger amount of functional groups in the alcohol component than in the carboxylic acid component in the copolycondensation reaction (JP-A-62).
-195677, 62-195678, 63-68849, 63-68850, 63-163469, JP-A-1-
155362, etc.).

The polyester resin as described above is used as the main component of the binder resin in the toner of the present invention. For example, in order to improve the pulverizability in forming a toner, styrene having a number average molecular weight of 11,000 or less, or styrene- Other resins such as acrylic resins may be used up to 30% by weight in the binder resin. When a toner is prepared, a property improving agent such as wax is added as an offset preventing agent, but when the polyester resin according to the present invention is used as a binder resin, the property improving agent does not have to be added because of excellent offset resistance. Moreover, even if it is added, the addition amount is small.

Next, various additives used for preparing the toner in the present invention will be described. The charge control agent is not particularly limited, and as the negatively chargeable toner, one kind or two or more kinds are used from all the negatively chargeable charge control agents known to be conventionally used for electrophotography. For example, metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31",
"Bontron S-32", "Bontron S-34",
"Bontron S-36" (all manufactured by Orient Chemical Co., Ltd.), "Aizen spirone black TVH" (manufactured by Hodogaya Chemical Co., Ltd.), a copper phthalocyanine dye, a metal complex of an alkyl derivative of salicylic acid, such as "Bontron E-8".
5 ”(manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salts such as Copy Charge NX VP 434 (manufactured by Hoechst), and the like.

As the positively chargeable toner, one kind or two or more kinds are used from all the positively chargeable charge control agents known to be conventionally used for electrophotography. As a specific example, an imidazole derivative such as "PLZ-
2001 "," PLZ-8001 "(above, manufactured by Shikoku Kasei Co., Ltd.), triphenylmethane derivative such as CO
PY BLUE PR (manufactured by Hoechst), quaternary ammonium salt compounds such as “Bontron P-51” (manufactured by Orient Chemical Co.), Copy Charge PXVP4
35 (manufactured by Hoechst), cetyltrimethylammonium bromide, and other polyamine resins, for example, "AFP-B"
(Manufactured by Orient Chemical Co., Ltd.) and the like. As another method of obtaining a positively chargeable toner, a styrene-acrylic resin obtained by copolymerizing the above-mentioned copolymerizable monomer containing an amino group can be used by mixing with another binder resin. . Further, if necessary, one type or two or more types of the above-mentioned positively chargeable charge control agent may be used in this system.

It is also possible to use a main charge control agent and a charge control agent of opposite polarity in combination, and the amount of the charge control agent of the opposite chargeability is 1/2 or less of the amount of the charge control agent of the main chargeability. In this case, even if the development is continuously performed on 50,000 sheets or more, the density is not lowered and a good visible image can be obtained. The above charge control agent is contained in the binder resin in an amount of 0.1 to 8.0% by weight, preferably 0.2 to 5.0% by weight.

As the colorant, a pigment such as a chromatic dye or carbon black, or a grafted carbon black obtained by coating the surface of carbon black with a resin is used, but all known ones can be used, and particularly limited. It is not something that will be done.

For example, for yellow, C.I. I. Solvent Yellow 21, C.I. I. Solvent Yellow 114,
C. I. Solvent Yellow 77, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 14, C.I.
I. Disperse Yellow 164 and the like can be mentioned. C. for magenta. I. Solvent Red 49, C.I. I. Solvent Red 128, C.I. I. Pigment Red 1
3, C.I. I. Pigment Red 48.2, C.I. I. Disperse Red 11 and the like can be mentioned. Cyan is C.I.
I. Solvent Blue 25, C.I. I. Solvent Blue 94, C.I. I. Pigment Blue 15.3 and the like can be mentioned.

If desired, the toner of the present invention may contain a fluidity improver, a cleaning improver, and the like. As the fluidity improver, for example, silica,
Alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, Magnesium oxide, zirconium oxide,
Examples thereof include barium sulfate, barium carbonate, calcium carbonate, silicon carbide and silicon nitride. Fine silica powder is particularly preferable.

The silica fine powder is Si--O--Si.
It is a fine powder having a bond and may be produced by a dry method or a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate,
It may be any of potassium silicate, magnesium silicate, zinc silicate, etc., but preferably contains SiO _{2 in an amount} of 85% by weight or more. Further, a fine powder of silica surface-treated with a silane coupling agent, a titanium coupling agent, a silicone oil, a silicone oil having an amine in a side chain, or the like can be used.

Examples of the cleaning property improver include metal salts of higher fatty acids typified by zinc stearate, fine particles of fluorine-based high molecular weight substances, and fine particles of silicone resin.

If desired, a release agent may be used in the toner of the present invention for the purpose of improving offset resistance in heat roller fixing. For example, any offset preventive agent such as polyolefin, fatty acid metal salt, fatty acid ester, partially saponified fatty acid ester, higher fatty acid, higher alcohol, paraffin wax, amide wax, polyhydric alcohol ester, silicone varnish, aliphatic fluorocarbon, silicone oil, etc. may be used. One or more of the above may be included.

The polyolefin is, for example, a resin such as polypropylene, polyethylene or polybutene and has a softening point of 80 to 160 ° C. Examples of the fatty acid metal salt include metal salts of maleic acid and zinc, magnesium, calcium, etc .; stearic acid and zinc, cadmium, barium, lead, iron, nickel, cobalt,
Metal salts with copper, aluminum, magnesium, etc .; dibasic lead stearate; oleic acid and zinc, magnesium,
Metal salts with iron, cobalt, copper, lead, calcium, etc .; Metal salts with palmitic acid and aluminum, calcium, etc .: Caprylate; Lead caproate: Metal salts with linoleic acid, zinc, cobalt, etc .; Calcium ricinoleate A metal salt of ricinoleic acid and zinc, cadmium or the like, or a mixture thereof. Examples of the fatty acid ester include maleic acid ethyl ester, maleic acid butyl ester, stearic acid methyl ester, stearic acid butyl ester, palmitic acid cetyl ester, montanic acid ethylene glycol ester and the like. Examples of the partially saponified fatty acid ester include partially saponified calcium of montanic acid ester. Examples of the higher fatty acid include dodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid,
Examples thereof include linoleic acid, ricinoleic acid, arachidic acid, behenic acid, lignoceric acid, ceracoleic acid and the like, and mixtures thereof. Examples of the higher alcohols include dodecyl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, arachin alcohol, and behenyl alcohol. Examples of the paraffin wax include natural paraffin, microwax, synthetic paraffin, and chlorinated hydrocarbon. Examples of the amide wax include stearic acid amide, oleic acid amide, palmitic acid amide, lauric acid amide, behenic acid amide, methylenebisstearamide,
Examples thereof include ethylene bis stearamide. Examples of the polyhydric alcohol ester include glycerin stearate, glycerin ricinoleate, glycerin monobehenate, sorbitan monostearate, propylene glycol monostearate, and sorbitan trioleate. Examples of the silicon varnish include methyl silicon varnish and phenyl silicon varnish. Examples of the aliphatic fluorocarbon include low-polymerization compounds of tetrafluoroethylene and propylene hexafluoride, and fluorine-containing surfactants described in JP-A-53-124428.

In addition to these, various additives can be used in the toner of the present invention. For example, an additive for adjusting the developability, for example, fine particle powder of a polymer of methacrylic acid methyl ester may be used.
Further, a small amount of carbon black may be used for toning and resistance adjustment. As the carbon black, conventionally known ones, for example, various ones such as furnace black, channel black and acetylene black can be used.

The developer of the present invention is subjected to a treatment in which inorganic fine particles having a small particle size are intentionally attached beforehand to the surface of a developer carrier by physical adhesion or electrostatic adhesion. It is obtained by electrostatically adhering a toner such as the above resin to a carrier by adding a toner containing a binder resin as a main component. It is possible to reduce the influence of migration and adhesion of fine powder toner. The physical adhesive force here means van der Waals force or image force.

On the other hand, when the surface of the carrier is not previously treated as in the present invention, immediately after mixing with the toner to produce the developer, the carrier surface is attached with the particles other than the toner particles. There are few of them, and the developer retains high chargeability. However, once the toner is set in the developing tank of a printer or a copying machine and the heat is generated by mechanical stirring and friction when the development is started, the surface treatment agent and minute toner applied to the toner surface are Adhesion or fusion is started on the surface or in the pores of the carrier, whereby the effective area of charge imparting of the carrier is sharply reduced, and a large charge fluctuation occurs. That is, for example, if the charge polarity of the toner is positive and the charge polarity of the carrier or the coating material on the surface of the carrier is negative, the positive charge control agent present at the interface when the toner is pulverized. And the like are electrostatically transferred to the surface of the carrier by contact with the surface of the carrier having negative polarity many times during printing, and substantially neutralize the negative polarity of the surface of the carrier. For this reason, the ability of the carrier to impart a positive charge to the toner is reduced, which causes a large fluctuation in the amount of charge.

In the present invention, as described above, since the inorganic fine particles are preliminarily adhered to the surface of the carrier and the charge imparting ability of the carrier is appropriately reduced from the initial stage of use, even if the initial stage of printing durability, the surface of the carrier becomes a toner. Even if the surface treatment agent migrates or is contaminated due to the adhesion of toner particles, the fluctuation of the charge amount can be reduced, and the resistance of the developer can be stabilized. Further, in the present invention, although the toner having excellent low-temperature fixability in which the spent on the carrier surface and the blocking of the developer are easily generated as described above is used, the inorganic fine particles are electrostatically relatively free on the carrier surface. Although it is not known exactly by adhering to the toner, those fine particles act as “rolls” on the carrier surface to prevent the spent of low molecular weight components in the toner and improve the fluidity of the developer. Therefore, it is possible to prevent the blocking of the developer for a long period of time. The function of the inorganic fine particles on the surface of the carrier as a “spacer” enables a developer which can be fixed at a low temperature and has a life of 100,000 sheets or more.

The developer obtained by the manufacturing method of the present invention can be applied to various developing methods. For example, there are a magnetic brush developing method, a cascade developing method, a method using a conductive magnetic toner, a method using a high resistance magnetic toner, a fur brush developing method, a powder cloud method and an impression developing method.

[0057]

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. The number of parts of the composition ratio shown below is
Unless otherwise specified, it is expressed in parts by weight. In addition, production examples of the binder resin and the toner used in the present invention, and production examples of the coated carrier particularly suitable in the present invention are also shown below.

Resin Production Example 1 714 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.
2) -2,2-bis (4-hydroxyphenyl) propane 6
63 g, isophthalic acid 518 g, isooctenyl succinic acid 70 g
80 g of 1,2,4-benzenetricarboxylic acid and 2 g of dibutyltin oxide were placed in a glass 3 L 4-necked flask, and a thermometer, a stainless stir bar, a downflow condenser, and a nitrogen inlet tube were attached to the mantle heater. The mixture was allowed to react with stirring in a nitrogen stream at 210 ° C.
The degree of polymerization was traced from the softening point according to ASTM E28-51 T, and the reaction was terminated when the softening point reached 130 ° C. The obtained resin is a pale yellow solid, and DSC (differential calorimeter)
The glass transition temperature was 65 ° C. The acid value of the resin was 18 KOHmg / g and the hydroxyl value was 35 KOHmg / g (OHV / AV = 1.94). The resin is referred to as a binder resin (1).

Resin Production Example 2 Resin Production Example 1 using 1050 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 339 g of azelaic acid and 141 g of 1,2,4-benzenetricarboxylic acid. Using the same equipment and procedure as above, the softening point was 122 ° C, the glass transition temperature was 60, the acid value was 19 KOHmg / g, and the hydroxyl value was 31 KOH.
mg / g of polyester resin was obtained (OHV / AV = 1.63)
. Let the said resin be binder resin (2).

Toner Production Example 1 Binder resin (1) 88 parts Carbon black "Regal 400R" (manufactured by Cabot) 8 parts Negatively chargeable charge control agent "Eisenspiron Black T-77" 2 parts (manufactured by Hodogaya Chemical Co., Ltd.) ) Wax "Viscole NP-105" (manufactured by Mitsui Petrochemical Industry Co., Ltd.) 2 parts After thoroughly mixing the above raw materials with a Henschel mixer, kneading with a twin-screw extruder equipped with a barrel cooling device, cooling,
After coarsely crushing, it was crushed by a jet mill and further classified by using an air classifier to obtain a fine powder having an average particle size of 11 μm. For 1000 g of this fine powder, hydrophobic silica “AE
3.0 g of "ROSIL R-972" (manufactured by Nippon Aerosil Co., Ltd.) was added and mixed and attached using a Henschel mixer to obtain a negatively chargeable toner 1.

Toner Production Example 2 Binder resin (2) 88 parts Carbon black "Regal 400R" (manufactured by Cabot) 8 parts Negative charge control agent "Eisenspiron Black T-77" 2 parts (manufactured by Hodogaya Chemical Co., Ltd.) ) Wax "Viscole NP-105" (manufactured by Mitsui Petrochemical Industry Co., Ltd.) 2 parts After thoroughly mixing the above raw materials with a Henschel mixer, kneading with a twin-screw extruder equipped with a barrel cooling device, cooling,
After coarsely crushing, it was crushed by a jet mill and further classified by using an air classifier to obtain a fine powder having an average particle size of 11 μm. For 1000 g of this fine powder, hydrophobic silica “AE
3.0 g of "ROSIL R-972" (manufactured by Nippon Aerosil Co., Ltd.) was added and mixed and adhered using a Henschel mixer to obtain a negatively chargeable toner 2.

Example of manufacturing coated carrier Ferrite carrier F-100 manufactured by Powder Tech Co., Ltd.
Silicone acrylic resin (manufactured by Toshiba Silicone Co., Ltd.) in which 1000 parts (average particle diameter 100 μm) was heated and maintained at 60 ° C. while being fluidized in a fluidized bed and dissolved in 5% with toluene.
Spray TSR-171) 10 parts (resin equivalent),
After drying for another 20 minutes, 200 ° C in an electric furnace,
Heat treatment was performed for 30 minutes to obtain a coated carrier.

Example 1 Monomethyl silicon coated ferrite carrier F96-100 (average particle size 100 μm) manufactured by Powder Tech Co., Ltd.
Hydrophobic silica "CAB-O" as inorganic fine particles in 960 g.
-SIL TS-530 (average particle size 0.02 μm) "
(Manufactured by Cabot) 28.8 mg (0.003 parts by weight)
Is divided into two equal parts, and charged in such a manner that they are sandwiched in a carrier layer, and V-type blender V-10
(Mixer manufactured by Tokuju Kosakusho Co., Ltd.) was used for mixing for 15 minutes at a rotating peripheral speed of 40 m / min to uniformly attach the inorganic fine particles onto the surface of the carrier. Next, 40 g of the negatively chargeable toner 1 is added to this preliminarily prepared carrier and mixed for 15 minutes under the same conditions,
Developer 1 is obtained.

Example 2 Example 2 except that the inorganic fine particles used for the surface treatment of the carrier of Example 1 were changed to amorphous titanium oxide "Titania IT-UD (average particle size 0.02 μm)" (manufactured by Idemitsu Kosan Co., Ltd.). Developer 2 was obtained in exactly the same manner as in 1.

Example 3 Zirconium oxide “NS-3Y (average particle size 0.02 μm)” containing 3 mol% of yttrium oxide as the inorganic fine particles used for the surface treatment of the carrier of Example 1 (manufactured by Nippon Shokubai Co., Ltd.) Developer 3 was obtained in the same manner as in Example 1 except that the content was changed to

Example 4 Coated Carrier 9 Coated Carrier Obtained in Production Example
Hydrophobic silica "AEROSI" as inorganic fine particles in 60 g
LR-972 (average particle size 0.02 μm) ”(manufactured by Nippon Aerosil Co., Ltd.) 28.8 mg (0.003 parts by weight)
Is divided into two equal parts, and charged in such a manner that they are sandwiched in the carrier layer, and a W cone blender (mixer manufactured by Tokuju Kosakusho) is used to rotate at a peripheral speed of 30 m / min for 10 minutes.
After mixing for a minute, the inorganic fine particles were uniformly attached on the surface of the carrier. Next, 40 g of the negatively chargeable toner 2 was added to this preliminarily prepared carrier and mixed under the same conditions for 10 minutes to obtain a developer 4.

Example 5 Exactly the same method as in Example 4 except that the inorganic fine particles of Example 4 were changed to amorphous titanium oxide "Titania IT-UD (average particle size 0.02 μm)" (made by Idemitsu Kosan Co., Ltd.). Thus, a developer 5 is obtained.

Example 6 Except that the inorganic fine particles of Example 4 were changed to zirconium oxide "NS-3Y (average particle size 0.02 μm)" containing 3 mol% yttrium oxide (manufactured by Nippon Shokubai Co., Ltd.). ,
Developer 6 was obtained in the same manner as in Example 4.

Comparative Example 1 Monomethyl Silicon Coated Ferrite Carrier F96-100 (average particle size 100 μm) manufactured by Powder Tech Co., Ltd.
960 g was charged into a V-type blender V-10 (Mixer manufactured by Tokuju Kosakusho Co., Ltd.), 40 g of the negatively chargeable toner 1 was added thereto without the treatment using the above-mentioned inorganic fine particles, and the rotational peripheral speed was 40 m / min. Comparative developer 1 was obtained by mixing for 15 minutes.

Comparative Example 2 Coated Carrier 9 Obtained in Production Example of Coated Carrier
60 g was charged into a W corn blender (mixer manufactured by Tokuju Seisakusho Co., Ltd.), 40 g of the negatively chargeable toner 2 was added thereto without the treatment with the above-mentioned inorganic fine particles, and the rotation peripheral speed was 30.
Comparative developer 2 was obtained by mixing at m / min for 10 minutes.

Test Example 1 (1) Evaluation of Charge Amount For the developers manufactured in Examples 1 to 6 and Comparative Examples 1 and 2, Developers 1 to 3 and Comparative Developer 1 are the copiers manufactured by Toshiba Corporation. BD-9240 "modified machine is used under normal standard setting conditions. For developers 4 to 6 and comparative developer 2, Sharp Co., Ltd. copier" SF-8800 "modified machine is modified under normal standard setting conditions. Used in a normal environment (23
An evaluation test of the charge amount was conducted at 50 ° C. and 50% RH.
The amount of charge was measured at the initial stage, 1,000 sheets, 10,000 sheets and 10 sheets.
The developers were sampled after printing ten thousand sheets, and each developer was sampled as follows. Moreover, the initial fluctuation of the specific charge was obtained as the difference between the initial value and the specific charge after printing 1,000 sheets. The device used was a blow-off type charge amount measuring device, and this device was a specific charge measuring device equipped with a Faraday cage, a condenser, and an electrometer. The measuring method was as follows. W (g) (about 3.0 g) of the prepared developer was put into a brass measuring cell equipped with a stainless mesh of 325 mesh (size that carrier particles do not pass). Next, suction was performed for 90 seconds from the suction port at a pressure indicated by the flow meter of 3 liters / min to remove only the toner from the cell. The voltage of the electrometer 90 seconds after the start of the suction was set to V (volt). Here, if the electric capacity of the condenser is C (μF), the specific charge Q / m of this toner is obtained by the following equation. Q / m (μc / g) = C × V / m where m is the weight of the toner contained in the development in W (g), the weight of the toner in the developer is T (g), When the weight of the developer is D (g), the toner concentration of the sample is T
/ D × 100 (%), and m is calculated by the following formula. m (g) = W × T / D

(2) Evaluation of Image Using the same evaluation equipment as the above-mentioned evaluation test of charge amount, a printing endurance test was conducted in a normal environment (23 ° C., 50% RH) under normal standard setting conditions. The image density and background stain were evaluated by the following methods. The image densities were evaluated by measuring the image densities at the initial stage and after printing 100,000 sheets using the Macbeth reflection densitometer RD-914 using each of the above devices. Regarding the evaluation of background stain, a colorimetric color difference meter Z-1001D was similarly measured during printing of 100,000 sheets.
The value obtained by subtracting the value of whiteness of the non-image area after development from the whiteness of the surface of an unused paper using P (manufactured by Nippon Denshoku Industries Co., Ltd.) was set as a relative comparison value of background stain, and Evaluation was made by comparing the values.

(3) Evaluation of blocking With respect to the evaluation of blocking of the developer, the developer after printing 100,000 sheets in the above-mentioned image evaluation was taken out from the developing tank, spread on a white plate, and visually and by hand. It was done by touching and comparing. The above results are also shown in Table 1.

[0074]

[Table 1]

As shown in the results of Table 1, the developers 1 to 6 produced in Examples 1 to 6 showed stable specific charges and image densities from the initial stage to after printing 100,000 sheets, and also caused scumming and blocking. I couldn't do it. On the other hand, in Comparative Developers 1 and 2 produced in Comparative Examples 1 and 2, a large initial fluctuation of the specific charge was observed, the image density was unstable, and scumming occurred after printing 100,000 sheets, and further blocking. Has occurred.

[0076]

According to the method for producing a developer of the present invention, unlike the conventional method, the developer obtained without impairing the productivity of the developer has an improved variation in the specific charge, and the life of the developer is improved. Therefore, the amount of charge can be stably maintained from the time of initial use.
Further, although the developer of the present invention uses a toner excellent in low-temperature fixability, the fluidity is improved by the effect of the surface treatment, so that high image quality is maintained for a long time without causing blocking. be able to. Further, the developer of the present invention is particularly excellent in stability of image density.

Claims (4)

[Claims] 1. A method for producing a developer, comprising the steps of adhering inorganic fine particles to the surface of a carrier by mixing the carrier and inorganic fine particles, and then electrostatically mixing and adhering the toner to the surface of the carrier. A method for producing a developer, wherein the main component of the binder resin is a polyester resin having an OHV / AV value of 1.2 or more, where AV is an acid value and OHV is a hydroxyl value of the resin. 2. The average particle size of the carrier is 55 to 160 μm.
The manufacturing method according to claim 1, wherein m is m. 3. A developer comprising a carrier and a toner having inorganic fine particles adhered to the surface of a carrier, wherein the main component of the binder resin of the toner is that the acid value of the resin is AV and the hydroxyl value is OHV. , A polyester resin having an OHV / AV value of 1.2 or more, containing 1 to 15 parts by weight of the toner with respect to 100 parts by weight of a carrier. 4. The average particle size of the carrier is 55 to 160 μm.
The developer according to claim 3, which is m.