JPH0627727A - Developer and manufacture thereof - Google Patents

Abstract

PURPOSE:To secure the long-run property of a developer without deteriorating the productivity of the developer to a large extent by specifying the main component of the binding resin of a toner. CONSTITUTION:A carrier is admixed with inorganic particles so as to attach the inorganic particles to the surface of the carrier and then a toner is electrostatically mixed and attached to the carrier surface. In this case, the main component of the binding resin of the toner is a polyester resin prepared by condensation copolymerization of a diol component expressed by formula I, a diol component expressed by formula II, a divalent carboxylic acid or its acid anhydride or its lower alkylester, and a polyvalent carboxylic acid having a valence of three or more or its acid anhydride or its lower alkylester, the former diol component being less than 10mol.%, the latter being 10mol.% or more and less than 25mol.%, and the polyvalent carboxylic acid being 2.5mol.% or more and less than 15mol.% of all the components. In the formulae, R is ethylene or a propylene group, (x) and (y) are each an integer of one or more, the average value of [x+y] is 2 to 7 and (n) is an integer of 2 to 6.

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. 1-
In JP-A-155362 and JP-A-2-127657, two or three specific diol components and a divalent or trivalent or more carboxylic acid component are copolycondensed as a main component of a binder resin of a toner. A developer excellent in low-temperature fixability has been proposed by using the polyester resin obtained as described above. 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. In the manufacturing method, the main component of the binder resin of the toner is (a)
General formula (1)

[0012]

[Chemical 7]

(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. ) The diol component represented by the formula (2) is less than 10 mol% in all the constituents, and

[0014]

[Chemical 8]

(In the formula, n is an integer of 2 to 6.)
10 mol% or more and less than 25 mol% of all constituent components, (c) divalent carboxylic acid or its acid anhydride or its lower alkyl ester, and (d) trivalent or more polyvalent. Carboxylic acid or its acid anhydride or its lower alkyl ester is 2.5 mol% or more and less than 15 mol% in all the constituents, and if necessary, (e) general formula (3)

[0016]

[Chemical 9]

A diol component represented by the formula (wherein R'is an alkylene group having 2 to 4 carbon atoms and n is an integer of 2 to 4) in an amount of 1.5 mol% to 10 mol based on all constituent components. % Of a polyester resin co-condensed with less than 1%, and (2) a developer comprising a carrier and a toner having inorganic fine particles adhered to the surface of the carrier, The main component of the binder resin is the above polyester resin,
The present invention relates to a developer containing 1 to 15 parts by weight of the toner with respect to 100 parts by weight of a carrier.

In the production method of the present invention, the inorganic fine particles are first adhered 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.

Specifically, for example, silica, alumina, titanium oxide and tin oxide, and the surface of which is made conductive by 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 cannot be unconditionally specified because it depends on the carrier and the particle size of the toner to be used, but 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 attached 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, a 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, but in the present invention, the carrier 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 A toner in which the main component of the binder resin of the toner is a polyester resin obtained by co-condensation of a specific two or three specific diol components and a divalent or trivalent or higher carboxylic acid component as described below. . The particle size of the toner depends on the size of carrier particles, but is usually 6 to 15
μm, preferably 8 to 13 μm is used. The toner used in the present invention may have either a positive charging property or a negative charging property.

Since the toner used in the present invention contains the above polyester resin as the main component of the binder resin, it has a wide offset range and low-temperature fixability. The polyester resin contains the following alcohol components. It is obtained by polycondensation with a carboxylic acid, a carboxylic acid ester, or a carboxylic acid anhydride.

Among the alcohol components, examples of the diol component (a) include 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-
Examples thereof include bis (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane. The diol component (a) is used in an amount of less than 10 mol% in all the constituent components, but if it is 10 mol% or more, the negative chargeability of the polyester resin increases, and it becomes difficult to obtain a positively chargeable toner, which is not preferable.

Examples of the diol component (b) include ethylene glycol, 1,3-propylene glycol, 1,4
-Butanediol, 1,5-pentanediol, 1,6-hexanediol and the like can be mentioned. Among them, ethylene glycol, 1,3-propylene glycol, 1,4-
Butanediol is preferably used. (B) The diol component is 10 mol% or more of all the constituents 2.
It is used in an amount of less than 5% by mole, but if it is less than 10% by mole, the minimum fixing temperature of the toner becomes high, and if it is 25% by mole or more, the resin becomes crystalline, which is preferable as described in JP-B-57-493. Absent. In some cases, other diols such as diethylene glycol, triethylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,4-butenediol, bisphenol A, hydrogenated bisphenol A, and other divalent Alcohol can be added.

Examples of the (c) carboxylic acid component of the present invention include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid. , Adipic acid, sebacic acid, azelaic acid, malonic acid, alkenylsuccinic acid or alkylsuccinic acid such as n-dodecenylsuccinic acid, n-dodecylsuccinic acid, anhydrides of these acids, lower alkyl esters, and other divalent Mention may be made of carboxylic acids.
Of these, terephthalic acid or its lower alkyl ester is particularly preferable.

The trivalent or higher polyvalent carboxylic acid or its derivative (d) in the present invention is a preferable component for improving the offset phenomenon, but when the amount is small, the effect is weak.
Further, when the pulverizability of the polyester resin and the toner is deteriorated and the amount thereof is large, it is difficult to control the reaction, and it is difficult to obtain a polyester resin having stable performance, and an unfavorable phenomenon such as an increase in the minimum fixing temperature occurs. Therefore, it is desirable that the amount of the trivalent or higher polyvalent carboxylic acid or its derivative (d) is 2.5 mol% or more and less than 15 mol% in all the constituent components. Specific examples of (d) trivalent or higher polyvalent carboxylic acids or their derivatives include, for example, 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,
Mention may be made of 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, their anhydrides, lower alkyl esters and other trivalent or higher carboxylic acids.

Examples of the diol component (e) include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, di-tetramethylene glycol, tri-tetramethylene glycol, tetra-tetraglycol. Mention may be made of methylene glycol. The diol component (e) is used in an amount of 1.5 mol% or more and less than 10 mol% in all the constituent components, but if it is less than 1.5 mol%, it is not effective in increasing the fixing strength, and if it is 10 mol% or more, the toner is used. It is not preferable because it causes blocking of.

The binder resin used in the present invention is preferably one having a softening point of 106 ° C. or higher and 160 ° C. or lower and a glass transition temperature of 50 ° C. or higher and 80 ° C. or lower. There is no effect in obtaining the offset region, and if the temperature exceeds 160 ° C., the unfavorable phenomenon occurs as the minimum fixing temperature increases. On the other hand, if the glass transition temperature is less than 50 ° C., the storage stability after toner formation will be poor, and if it exceeds 80 ° C., the fixability will be adversely affected, which is not preferable.

The polyester resin used in the present invention can be produced by polycondensing a polyvalent carboxylic acid component and a polyol component at a temperature of 180 to 250 ° C. in an inert gas atmosphere. At this time, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate or the like can be used. For the same purpose, it can be produced under reduced pressure. The polyester resin of the present invention thus obtained is a resin having good grindability.

The polyester resin in the present invention is used as the main component of the binder resin, and has a number average molecular weight of 11,000 in order to further improve the pulverizability in toner formation.
The following styrene or styrene-acrylic resin, etc.
Other 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 anti-offset agent, but when the polyester resin according to the present invention is used as a binder resin, the property improving agent may not be added, or when it is added. However, 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 chromatic dye or a pigment such as carbon black, or a grafted carbon black obtained by coating the surface of carbon black with a resin is used. All known pigments can be used, and particularly limited. It is not something that will be done.

For example, yellow has 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 fine silica 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 necessary, 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, polybutene and the like, 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 the inorganic fine particles having a small particle size are intentionally attached beforehand to the surface of the 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, in the case where the surface of the carrier is not previously treated in the present invention, the particles other than the toner particles are attached to the surface of the carrier immediately after the developer is prepared by mixing with the toner. 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 when 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. Further, the toner of the present invention tends to generate fine powder in the developing tank a little more than the toner using a general polyester resin, but it can be reduced by the surface treatment of the present invention.

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.

[0051]

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 Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 164.9 g, ethylene glycol 86.5 g, 1,2-propylene glycol 84.4
g, dimethyl terephthalate 430.7 g, 1,2,4-benzenetricarboxylic acid anhydride (trimellitic anhydride) 10
6.6 g and 1.2 g of dibutyltin oxide were placed in a glass 2-liter 4-necked flask, equipped with a thermometer, a stainless stir bar, a downflow condenser, and a nitrogen inlet tube, and nitrogen was placed in a mantle heater. 17 under airflow
The reaction was carried out at 0 ° C. for 5 hours and then at 220 ° C. with stirring. The degree of polymerization was traced from the softening point according to ASTM E 28-51 T, and the reaction was terminated when the softening point reached 130 ° C. The obtained resin is a pale yellow solid and has a DSC
The glass transition temperature by a (differential calorimeter) is 63 ° C.,
Let the said resin be binder resin (1).

Resin Production Example 2 72.1 g of ethylene glycol, 15.7 g of 1,4-butanediol and 115.5 of 1,2-propylene glycol.
g, diethylene glycol 12.3 g, dimethyl terephthalate 430.7 g, 1,2,4-benzenetricarboxylic acid anhydride (trimellitic anhydride) 106.6 g, and 1.
2 g of dibutyltin oxide was placed in a glass 2-liter four-necked flask, equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen introduction tube, and heated to 170 ° C. in a mantle heater under a nitrogen stream. For 5 hours and then reacted at 220 ° C. with stirring. The degree of polymerization is A
Followed from the softening point according to STM E 28-51 T,
The reaction was terminated when the softening point reached 130 ° C. The obtained resin was a pale yellow solid and had a glass transition temperature of 61 ° C. measured by DSC (differential calorimeter), which was designated as a binder resin (2).

Toner Production Example 1 Binder resin (1) 88 parts Carbon black "Regal 400R" (manufactured by Cabot) 8 parts Negative charge control agent "Aizenspiron 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
ROSIL R-972 (average particle size 0.02 μm) ”
(Nippon Aerosil Co., Ltd.) (3.0 g) was added and mixed and adhered using a Henschel mixer to give a negatively charged toner 1.
Got

Toner Production Example 2 Binder Resin (2) 88 parts Carbon Black "Regal 330R" 7 parts Positively chargeable charge control agent "Bontron N-07" 2 parts (Orient Chemical Co.) Positively chargeable charge control agent " TP-415 "(manufactured by Hodogaya Chemical Co., Ltd.) 1 part Wax" Luwax ES9675 "(manufactured by BASF) 2 parts The above raw materials are kneaded and pulverized in the same manner as in Toner Manufacturing Example 1.
Classification was performed to obtain 11 μm fine powder. 1000 of this fine powder
Hydrophobic silica “HVK-2150” (Wac
ker chemie) was added and mixed and attached using a Henschel mixer to obtain a positively 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)" (made 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 Obtained in Production Example of Coated Carrier
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 positively 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)” (manufactured by Nippon Shokubai Co., Ltd.) containing 3 mol% of yttrium oxide. ,
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 Kosakusho Co., Ltd.), 40 g of the positively chargeable toner 2 was added thereto without the treatment using the inorganic fine particles as described above, 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 Regarding 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 density was evaluated by measuring the image density using a Macbeth reflection densitometer RD-914 while printing 100,000 sheets using each of the above devices. Regarding the evaluation of background stain, a colorimetric color difference meter Z-1001 was similarly measured during printing of 100,000 sheets.
Using DP (Nippon Denshoku Industries Co., Ltd.), the value obtained by subtracting the value of the whiteness of the non-image area after development from the whiteness of the surface of the unused paper was taken as the relative comparison value of background stain, and Evaluation was made by comparing the values.

(3) Evaluation of blocking With respect to the evaluation of the blocking of the developer, 20 g of the developer after printing 100,000 sheets in the developing tank in the above image evaluation was used.
Extract it and use it as a micro-type electromagnetic vibration sifter M-100
90 mesh (1 type) (manufactured by Tsutsui Rikagiki Kikai Co., Ltd.)
It was gently placed on a mesh of 66 μm and vibrated with the intensity of the scale 4 for 10 seconds, and then the blocking rate was calculated from the weight of the cohesive developer remaining on the mesh. The calculation was performed by the following formula. Blocking rate (%) = weight of cohesive developer (g) / 20
(G) × 100 The above results are also shown in Table 1.

[0068]

[Table 1]

As shown in the results of Table 1, the developers 1 to 6 produced in Examples 1 to 6 have a stable specific charge from the initial stage to after printing 100,000 sheets, the image density is good, and the background stain is not generated. None, and the blocking rate was low. On the other hand, Comparative Examples 1 to
In Comparative Developers 1 and 2 produced in No. 2, a large initial change in specific charge was observed, the initial image density was lowered, white spots were generated after printing 100,000 sheets, and background stain was generated after printing 1000 sheets. In addition, the blocking rate was high, which caused image unevenness such as white spots.

[0070]

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.

Claims (10)

[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. The main component of the binder resin is (a) general formula (1) (In the formula, 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).
Is. ) The diol component represented by
When it is less than mol%, (b) the general formula (2): (In the formula, n is an integer of 2 to 6), and 10% by mole or more and less than 25% by mole of all the constituent components, (C) a divalent carboxylic acid or an acid anhydride thereof, or Polyester resin obtained by copolycondensation of the lower alkyl ester and (d) trivalent or higher polyvalent carboxylic acid or acid anhydride thereof or lower alkyl ester thereof in an amount of 2.5 mol% or more and less than 15 mol% in all constituent components. And a method for producing a developer. 2. A polyester resin further comprising (e) the general formula (3): (In the formula, R ′ is an alkylene group having 2 to 4 carbon atoms, and n is 2 to
It is an integer of 4. The manufacturing method according to claim 1, wherein the diol component represented by (4) is contained in an amount of 1.5 mol% or more and less than 10 mol% in all the constituent components. 3. The production method according to claim 1, wherein the main component of the divalent carboxylic acid according to claim 1 is terephthalic acid or a lower alkyl ester thereof. 4. The softening point of the binder resin according to claim 1 is 10.
6 ° C or higher and 160 ° C or lower and a glass transition temperature of 50
The method according to claim 1, wherein the temperature is not less than 80 ° C and not more than 80 ° C. 5. The average particle size of the carrier is 55 to 160 μm.
m is a manufacturing method in any one of Claims 1-4. 6. In a developer comprising a carrier and a toner in which inorganic fine particles are adhered to the surface of a carrier, the main component of the binder resin of the toner is (a) the general formula (1): (In the formula, 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).
Is. ) The diol component represented by
When it is less than mol%, (b) the general formula (2): (In the formula, n is an integer of 2 to 6), and 10% by mole or more and less than 25% by mole of all the constituent components, (C) a divalent carboxylic acid or an acid anhydride thereof, or Polyester resin obtained by copolycondensation of the lower alkyl ester and (d) trivalent or higher polyvalent carboxylic acid or acid anhydride thereof or lower alkyl ester thereof in an amount of 2.5 mol% or more and less than 15 mol% in all constituent components. A developer containing the toner in an amount of 1 to 15 parts by weight based on 100 parts by weight of a carrier. 7. A polyester resin further comprising (e) a compound represented by the general formula (3): (In the formula, R ′ is an alkylene group having 2 to 4 carbon atoms, and n is 2 to
It is an integer of 4. The developer according to claim 6, wherein the diol component represented by the formula (1) is contained in an amount of 1.5 mol% or more and less than 10 mol% in all the constituent components. 8. The developer according to claim 6, wherein the main component of the divalent carboxylic acid according to claim 6 is terephthalic acid or a lower alkyl ester thereof. 9. The softening point of the binder resin according to claim 6 is 10.
6 ° C or higher and 160 ° C or lower and a glass transition temperature of 50
7. The developer according to claim 6, which has a temperature of not lower than 80.degree. 10. The average particle size of the carrier is 55 to 160.
The developer according to any one of claims 6 to 9, which has a thickness of μm.