JPH0470854A - Developer - Google Patents

Abstract

PURPOSE:To prevent the unfavorable reproducibility of dots and a void phenomenon of a dotted picture, etc., generated when this developer is used for such a reversal phenomenon such as a laser printer by using a specified developer. CONSTITUTION:The developer is consisting of a resin coated carrier having plural fine pores on the surface and a pulverized toner subjected to a spherical treatment. The toner is mixed and kneaded with a resin, a coloring agent, a charge control agent, an offset preventive, etc., and the toner obtained by pulverizing and classifying is further performed with a spherical treatment and is used as a toner particle having practically no angle. Also the carrier consists of a carrier core material 1, a resin coated layer 2 and fine pores 3 formed on the surface of the layer 2 and, the cracking property of the toner (floculation prevention) by making plural fine pores 3 present thereon, an electrostatical chargeability rising characteristic of the toner and the electrostatical chargeability stability of the toner are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developer comprising a resin-coated carrier having a large number of pores on its surface and a pulverized toner.

Conventional technology Traditionally, as an electrostatic latent image development method, the toner is triboelectrically charged by mixing toner and a magnetic carrier, and the toner is conveyed to the electrostatic latent image by a magnetic brush formed by the magnetic carrier and developed. A two-component development method is known.

As toners used in the two-component development method, pulverization method toner, suspension polymerization method toner, suspension granulation method toner, microcapsule method toner, spray dry method toner, mechanochemical method toner, etc. are known. Pulverized toners are widely used in practice from the viewpoint of yield, manufacturing stability, and the like.

On the other hand, as carriers, iron powder carriers, ferrite carriers, resin-coated carriers, binder-type carriers, etc. are known, and a two-component developer prepared by appropriately mixing these carriers and pulverized toner is used in laser printers, etc. When applied to a reversal development method, the reproducibility of dots is poor and a phenomenon (called voids) occurs in the halftone image. The present invention aims to solve the above-mentioned problems from the viewpoint of a specific combination of toner and carrier. The image quality of a copied image largely depends on the individual characteristics of the toner and carrier, as well as the combined characteristics of the toner and carrier. For example, various forms of toner manufactured and processed by various methods are known (for example, Japanese Patent Publication No. 63-63251,
JP-A-62-209542, JP-A-1-9374
No. 9, JP-A No. 63-244052, etc.).

Japanese Patent Publication No. 63-63251 discloses a spherical toner obtained by stirring and flowing with hot air in a hot air treatment device having a rotor inside.

JP-A No. 62-209542 discloses a toner obtained by subjecting a mechanical strain to substantially no particles of 5 μm or less, and a toner obtained by processing a kneaded and pulverized toner in a free mill. .

JP-A No. 1-93749 discloses a method for producing strong, imperfectly spherical toner particles having a high bulk density of 0.335 by applying a mechanical impact force to colorant-containing emulsion polymer particles.

In the above three publications, the carrier used in combination with the toner is a conductive carrier such as an iron powder carrier. When a developer combined with such a low resistance carrier is used in a reversal development system, the generation of voids is unavoidable.

Furthermore, Japanese Patent Application Laid-open No. 63-244052 discloses that after pulverized and classified particles are rounded so that the short axis/long axis is -0.70 to 0.90 degrees, child particles are attached to the particle surface. Next, the obtained rt toner and non-condensed toner were fixed by impact force (
SL) A developer obtained with a resin-coated ferrite carrier is disclosed, but the structure of the toner and carrier is different from the present case.

Problems to be Solved by the Invention The present invention solves the problem of poor reproducibility of dots and white spots in halftone images that occur when a developer using pulverized toner is used in a reversal development device such as a laser printer. (void)
The object of the present invention is to provide a developer that prevents the development of the like.

Means for solving the problem, that is, the present invention provides a developer comprising a resin-coated carrier having a large number of pores on its surface and a pulverized toner that has been subjected to a spheroidization process.

According to the present invention, by combining a resin-coated carrier having a large number of pores on the surface with a spherical toner, the toner can be uniformly charged and white spots can be prevented.

The pulverized toner has a distribution in particle size, and furthermore, the shape of each toner varies. By subjecting such a pulverized toner to spheroidization according to the present invention, the shape of the toner can be made uniform to some extent, and fine particles contained in the toner can be removed. Adjusting the particle size and shape of the toner in this way contributes to uniform charging of the toner.

Even when the toner is spheroidized, the toner still has its shape and particle size distribution. In particular, if the toner has a particle size distribution, small particle size toner is easily charged, while large particle size toner is easily charged. Since it is difficult to be charged, variations in the amount of charge cannot be completely eliminated. According to the present invention, when a carrier having a large number of pores on the surface is used, due to its excellent charging property, even large particle size toner can be sufficiently charged, and the amount of charge on the toner can be made uniform. be able to. In addition, if toner aggregation occurs, this will also cause non-uniform charging of the toner, but the porous carrier has excellent toner disintegration properties and can achieve a uniform charging amount of the toner. .

In other words, by adjusting the shape and particle size of the toner and using a carrier with a large number of pores on the surface, it is possible to equalize the charge amount of each toner, and the above-mentioned white spots can be effectively prevented. Ru. The developer of the present invention comprises a resin-coated carrier having at least a large number of pores on its surface and a spherical pulverized toner.

First, toner will be explained. The present invention can be applied to any toner obtained by a pulverization method.
Consists of thermoplastic resin, colorant, charge control agent, offset inhibitor, etc.

Toner resin used in the present invention 11,
Acrylic resins having polar groups such as carboxyl, hydroxyl, glycidyl, and amine groups; acrylic acid monomers such as methacrylic acid, acrylic acid, maleic acid, and itaconic acid; hydroquine polypropylene monomethacrylate; Examples include monomers having a hydroxyl group such as polyethylene glycol monomethacrylate; monomers having an amine group such as dimethylaminoethyl methacrylate; monomers such as nigrindyl methacrylate copolymerized with lower alkyl acrylic acid esters and/or styrene.

Also, polyester resins such as ethylene glycol, triethylene glycol, 2-propylene glycol, 1,4-butanediol, and other polyols are condensed with dicarboxylic acids such as maleic acid, itaconic acid, malonic acid, etc. Examples include polyester resins and thermoplastic resins such as Epoquine resins.

These resins may be three-dimensionally crosslinked to adjust their viscosity.

Furthermore, in addition to the above-mentioned resins, vinyl resins, rosin-modified phenol-formalin resins, cellulose resins, polyether resins, silicone resins, fluororesins, etc. can be mentioned.

Colorants to be included in the toner include black pigments such as carbon black, acetylene black, lamp black, and aniline black; red pigments such as red pigment, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, resol red, and pyrazolone red. ,
Watching red, calcium salt, lake red D1
Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B1 Alizarin Lake, Brilliant Carmino 3B, etc.; Green pigments include chrome green, chromium oxide, Pigment Green B1 Malachite Green Lake, 7-analyte low green, etc.; Blue pigments include navy blue, cobalt blue, Alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue phthalocyanine blue partially chlorinated product, fast sky blue, industhrene blue BC, etc.; manganese purple as magenta pigment, 7 astoviolet B1 methyl violet lake, etc.; sepia pigment Permanent brown, para-brown, etc. as white pigments; Zinc white, titanium oxide, antimony white, zinc sulfide, etc. as white pigments; Yellow pigments as yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow nickel titanium yellow, impermanent yellow ~ Naphthol Yellow S1 Hansa Yellow G1 Hansa Yellow LOG, Benzidine Yellow G1 Benzidine Yellow GR, Quinoline Yellow Lake, Permanent Yellow, NCG, Tartrazine Lake, etc.: Orange pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange , Palkan Orange, Indus Thread Brilliant Orange RK, Benzidine Orange G1 Indus Thread Brilliant Orange GK, etc.

The amount of these pigments (colorants) used is 1 to 10% of the total amount of toner.
20% by weight, more preferably 3-7% by weight is suitable.

In the toner of the present invention, a dye that also serves as charge control may be used alone or in combination with the pigment (coloring agent) or the like, if necessary. Among these charge control agents, typical ones that impart positive chargeability to toner include basic dyes such as nigrosine oil-soluble dyes and crystal violet, and typical ones that impart negative chargeability. Examples include metal complex dyes such as baratin dyes and orazole dyes.

These colorants or charge control agents are mixed and dispersed in a proportion of 2 to 20 parts by weight based on 100 parts by weight of the thermoplastic resin.

The toner of the present invention may contain an anti-offset agent in order to improve fixing properties. Examples of the offset inhibitor include Wanx, low molecular weight polypropylene, polyethylene, and oxidized polypropylene and polyethylene.

The toner produced by the pulverization method is obtained by mixing and kneading the above-mentioned resin, colorant, charge control agent, offset inhibitor, etc., and pulverizing and classifying the mixture by a conventional method. The toner particles obtained by this pulverization method are inevitably angular because they undergo a pulverization process.

In the present invention, the toner obtained by the pulverization method is further spheroidized to form toner particles with substantially no corners. The toner particles having substantially no corners are to such an extent that the effects of the present invention can be obtained when a developer is prepared in combination with the carrier of the present invention described later and applied to reversal development in a laser printer, etc. This means that the particles have been processed to have rounded corners and become spherical, but it does not necessarily mean that the processing must be applied to particles with completely rounded corners.

There are no particular limitations on the method of spheroidization, but for example, a hybridization system that applies a high-speed air impact method (manufactured by Nara Kikai Seisakusho Co., Ltd.), Cosmon Stem (manufactured by Kawasaki Heavy Industries, Ltd.), Ongmil (Honkawa), etc. (manufactured by Micron Corporation), etc., or any other method may be used as long as particles with substantially rounded edges can be obtained as described above.

Thus, the toner is obtained with an average particle size of about 3 to 20 μ4.

A fluidizing agent may be externally added to the toner obtained as described above to improve fluidity.

Examples of the fluidizing agent include silica, aluminum oxide, titanium oxide, a mixture of silica and aluminum oxide, and a mixture of silica and titanium oxide.

Next, a carrier having a large number of pores on its surface to be used in combination with the toner of the present invention will be described.

For ease of understanding, a cross-sectional view of the resin-coated carrier of the present invention is schematically shown in FIG. 1, and a schematic cross-sectional view of a conventional resin-coated carrier is shown in FIG.

That is, the resin-coated carrier of the present invention includes a carrier core material (1) and a resin coating layer (2) covering the carrier core material (1).
), consisting of pores (3) formed on the surface of the resin coating layer.

Compared to the conventional resin-coated carrier shown in Figure 3, the pores (
3) is a major feature.

In this way, when a large number of pores are present on the surface of the resin-coated carrier, the toner has excellent disintegration properties (anti-agglomeration properties), toner charging build-up characteristics, and toner charging stability. This is considered to be because the presence of pores increases the probability of contact with the toner and the number of contact points, and the concentration of charge on the convex portions occurs.

The pores on the surface of the resin-coated carrier of the present invention are specifically defined by its pore size distribution, average pore diameter, and total pore volume.

The diameter of each pore existing on the surface of the resin coating layer is 0.001-37
711. Preferably 0.001-2μI11. More preferably, the distribution is in the range of 0.005 to 2 μm. If the pore size is smaller than 0.001/7 m, sufficient effects cannot be expected from the viewpoint of toner crushability, and if the pore size is larger than 3 μm, the toner trapping property will be too strong, resulting in poor fluidity and developability. There is a risk of damage.

The average pore diameter corresponds to the pore diameter distribution range mentioned above.
It is desirable that it be in the range of 0.1 to 0.5 μm. By setting the average pore diameter within the above range, the crushability of the toner and the charging characteristics of the toner can be improved.

In the present invention, the total pore volume is expressed in two ways: total pore volume per gram of carrier (mM9) and total pore volume per coated resin layer LrnQ (IIQ/ml2).

The total pore volume (1112/9) per gram of carrier can be determined by mercury porosimetry. In the carrier of the present invention, the value is 0.001 to 0, LmQ
/g, preferably 0.01-0.05 mL'g. The value is 0.001(m(1/i
If it is smaller than +), there are insufficient pores present on the carrier surface, and there is a possibility that the effect of the pores may not be obtained. If it is larger than 0.1 mQ/g, there will be too many pores and the coating layer will become brittle.

The total pore volume (CmQ/mQ) per coating resin 1+IIQ can be determined by converting from the true specific gravity of the gear 9F1 coating layer and the carrier core material filling rate described above. In the carrier of the present invention, the value is 0.1 to 2 mQ/rnQ.

Preferably, it has a value of 0.5 to 1.5 mQ/mQ. Its value is 0, 1 mQ/m
If it is smaller than Q, there will be insufficient pores present on the carrier surface, and there is a possibility that the effect of the pores will not be obtained. 2
If it is larger than mQ/mα, there will be too many pores and the coating layer will become brittle.

The carrier core material should be at least 20 μm (average particle diameter) in order to prevent carrier adhesion (scattering) to the electrostatic latent image carrier, and to prevent carrier streaks and other deterioration in image quality. From the viewpoint of prevention, one with a diameter of at most 100 μm is used. Specific materials include those known as two-component carriers for electrophotography, such as metals such as ferrite, magnetite, iron, nickel, and cobalt, and these metals and zinc, antimony, aluminum, lead, tin, bismuth, beryllium, and manganese. , alloys or mixtures with metals such as selenium, tungsten, zirconium, and vanadium, metal oxides such as iron oxide, titanium oxide, and magnesium oxide, nitrides such as chromium nitride and vanadium nitride, and carbides such as silicon carbide and tungsten carbide. Mixtures and ferromagnetic ferrites, mixtures thereof, etc. can be applied.

Examples of carrier coating resins include polystyrene resins, poly(meth)acrylic resins, polyolefin resins, polyamide resins, polycarbonate resins, polyether resins, polysulfinic acid resins, polyester resins, epoxy resins, and polyester resins. Butyral resin, urea resin,
Various thermoplastic resins and thermosetting resins such as urethane/urea resins, silicone resins, polyethylene resins, and Teflon resins, and mixtures thereof, as well as copolymers, block polymers, graft polymers, and Polymer blends and the like are used. Furthermore, in order to improve charging properties, resins having various polar groups may be used.

In particular, if the toner used in combination with a carrier is a toner with a small particle size, the smaller the particle size of the toner, the smaller the toner's heat capacity and the more likely it is to become spent. From this point of view, coating resins with good mold releasability, such as silicone resins or polyolefin resins, are preferred.

The surface of the carrier of the present invention is covered with resin at least 70%, preferably at least 90%, more preferably at least 95%. In the present invention, polyethylene is particularly preferred. If the coverage is less than 70%, the characteristics of the carrier core material itself (unstable environmental resistance, decreased electrical resistance, unstable charging) will be strongly visible through the background, making it impossible to take advantage of the advantages of the resin coating.

The filling rate of the carrier core material is set to about 90vt% or more, preferably 95vt% or more. The filling rate is expressed as something that indirectly defines the thickness of the resin coating layer of the carrier. If the carrier filling rate is less than 90 wt%, the coating layer becomes too thick, and even if it is actually applied to a developer, Problems such as peeling off of the coating layer, increase in the amount of charge, etc., which do not satisfy the durability and charge stability required of the developer, and poor fine line reproducibility and decrease in image density occur in terms of image quality. .

It is also possible to express the resin coating layer thickness indirectly by specific gravity. The specific gravity of the carrier of the present invention is greatly influenced by the type of carrier core material, but as long as the carrier core material is used, the specific gravity of the carrier of the present invention is 3.5 to 7.5, preferably 4.0 to 6.0, more preferably 4.0 to 6.0. It shows a value within the range of about 4.0 to 5.5. If the value is outside this range, the same disadvantages as those caused by the carrier not being coated with an appropriate filling rate will occur as described above.

The electrical resistance of the resin-coated carrier of the present invention is lX10'-
IXIOIIΩ" Cm, preferably 10' to 10 Ω
cm, more preferably about 10"-10"Ω'cm. If the electrical resistance is less than 1X I O'Ωcm, carrier development will occur and the image quality will deteriorate.
When xlO is larger than 14 Ω·cm, the toner is excessively charged, making it impossible to obtain an appropriate image density. The electrical resistance can also be viewed as an indirect expression of the resin coverage and carrier filling rate described above.

Preferably, the carrier used in the present invention further provides unevenness to the resin coating layer. Figure 2 shows the resin coating layer (2
) shows an uneven form, and the pores (3) are present on the uneven surface of the resin coating layer (2). By imparting such irregularities to the surface of the carrier, it is possible to obtain a carrier with improved toner charge rise characteristics, toner scattering, toner agglomeration and disintegration properties, and the like.

Surface unevenness will be explained in more detail.

The surface unevenness structure of the surface coating layer is expressed by the following formula [■]; [where the outer periphery represents the outer periphery of the projected image of the carrier particles, and the area represents the average value of the projected area of the carrier particles. ] The value is preferably within the range of 130 to 200.

The S value represents the degree of unevenness on the particle surface, and the greater the degree of unevenness of the surface state, the further the value becomes from 100. The shape factor S is. For example, it can be measured using an image analyzer (Luzenkus 5000, manufactured by Nippon Regulator Co., Ltd.); however, in general, when measuring the shape factor S, there is no significant difference depending on the model, so it must be measured with the above model in particular. does not mean.

Further, additives such as fine particles having a charge imparting function or conductive fine particles may be added to the coating layer of the carrier of the present invention.

Examples of fine particles with a charge imparting function include Cry, Fe2
O,,Fe,O,,IrO2,MnO2,MOO2,N
bO2, pto, , TiO2, Ti20U, Ti3O5
,W0□,v203,AlzOs,MgO,5i02,
Examples include metal oxides such as ZrO2 and BaO, dyes such as Nigro/Inbase, and Subiron Blank TRH.

Examples of conductive fine particles include carbon blank, acetylene black, carbon black, and SiC.

Carbide such as TiC, MoC, ZrC, BN, NbN.

Examples include nitrides such as T i N % Z r N, and magnetic powders such as ferrite and magnetite.

Addition of metal oxides, metal fluorides, and metal nitrides is effective in further increasing chargeability. It is believed that this effect is produced by the synergistic charging effects of each component and the toner due to the contact between the toner and the complex interface composed of these compounds and the core material.

Addition of carbon black is effective in improving developability and obtaining images with high image density and clear contrast. This is thought to be because the addition of conductive fine particles such as carbon black lowers the electrical resistance of the carrier appropriately, and balances leakage and accumulation of charge.

One of the characteristics of conventional binder-type carriers is that they have excellent halftone reproducibility and gradation reproducibility, but in the case of the coated carrier of the present invention, by adding magnetic powder to the resin coating layer, A gear rear with excellent gradation reproducibility can be obtained.

This is thought to be because the addition of magnetic powder to the polyolefin coat layer resulted in a surface composition similar to that of the binder-type carrier, and the chargeability and specific gravity approached those of the binder-type carrier.

Addition of borides and metal carbides has an effect on the rise of charging.

The size, amount, etc. of the above additives are not particularly limited as long as they satisfy the various properties of the carrier of the present invention, such as coverage and electrical resistance.
0.01μm1 preferably 1-0. It is sufficient that the thickness is about 01 μm.

Further, as for the amount of both of the above-mentioned fine particles added, although the amount cannot be specified in part as described above, it is O.lvt% to 50vt%, preferably 1. ow
t% to 4Qwt% is suitable.

In particular, when using the present invention with a filling rate set in the range of 90 to 97 wt%, it is preferable to add additives such as fine particles with a charge imparting function or conductive fine particles to the resin coating layer. When the filling rate of the carrier is as small as about 90 wt% and the thickness of the coating layer is relatively thick, when continuous copying of fine lines is performed using such a carrier, a problem arises in that the reproducibility decreases. The problem is solved by the addition of the above additives.

Next, a method for producing a resin-coated carrier having pores according to the present invention will be explained. The method for producing the carrier of the present invention is not particularly limited as long as the carrier having the above-mentioned pores can be obtained, but the following two methods are preferably used.

One of the preferred manufacturing methods is to disperse fine particle components soluble in a suitable solvent in advance in a coating resin solution, and after forming the coating layer, the fine particles are immersed in a soluble solvent to elute the soluble fine particle components. A method of forming pores on the surface of the coating layer can be mentioned. In this method, the pore size is determined by the particle size of the solvent-soluble fine particle component, the degree of dispersion, etc. Further, the coating layer can be formed by a powder capsule method, a spray dry method, or the like.

As fine particle components that can be used in this method, there may be mentioned fine particles of metal oxides such as ferrite, halides or hydroxides of alkali metals or alkaline earth metals, transition metal complexes, and the like.

It goes without saying that it is necessary to use a solvent that does not dissolve the resin at the same time.

More specifically, for example, there is a method in which ferrite is eluted by immersing a carrier having a resin coating layer containing ferrite in an acidic aqueous solution such as hydrochloric acid, thereby forming pores on the carrier surface. can do.

Furthermore, when adding the above-mentioned fine particles having a charge imparting function or conductive fine particles, these additives may be added and present in the coating resin solution, or pore-forming particles such as ferrite can be added. The use of particles that function both as electrically conductive fine particles and as conductive fine particles is advantageous from the viewpoint of the manufacturing method and properties.

Another preferred method for producing the carrier of the present invention is a surface polymerization coating method.

The surface polymerization coating method uses: ■ a highly active catalyst component that contains titanium and/or zirconium and is soluble in a hydrocarbon solvent; It can be formed by polymerizing an olefin monomer, such as ethylene, on the surface of the carrier core material. Furthermore, when fine particles having a charge imparting function or conductive fine particles are added, these additives may be added and present at the time of forming the above-mentioned coating layer. Specifically, Japanese Patent Publication No. 60106808
The method described in the publication is suitable.

This publication is hereby incorporated by reference as part of this specification.

When a carrier coating layer is formed by this surface polymerization coating method, in addition to being able to form a coating layer having pores on the surface of the carrier as described above, film strength and
A durable carrier with excellent adhesion between the core particles and the resin coating layer can be obtained.

In particular, the weight average molecular weight of the polyolefin is 5゜0x10
"~5.0X105, preferably 1.0X104~4.
5XIO', more preferably 5.0XIO' to 4.0X
When it is 1O', the polyolefin resin layer can have excellent resin strength and adhesion to the carrier.

If the average molecular weight is less than 5XIO', the surface of the coating layer will not have any unevenness. In addition, developability deteriorates.

On the other hand, if the average molecular weight exceeds 5x10', the coating layer becomes hard and lacks adhesion to the surface of the core material, resulting in decreased durability.

In order to further improve the adhesion between the polyolefin resin layer and the carrier core material, it is effective to conduct the polymerization under conditions such that the molecular weight is low at the initial stage of polymerization.

The carrier having the surface unevenness structure obtained as described above may be further subjected to heat treatment. Such heat treatment is
Effective in preventing image density from decreasing.

The heat treatment method includes, for example, ■ treatment in a hot air stream;
Examples include (1) treatment in a heating medium, (2) treatment in a rotating electric furnace, but there are no particular limitations as long as the method can provide appropriate heating and friction.

In the present invention, the carrier and toner obtained as described above are mixed to form a developer.

The developer obtained in this way has chargeability, electrostatic properties,
It has excellent spent resistance, charge stability, environmental resistance, etc.
Furthermore, even when used in reversal development in a laser printer or the like, it is possible to form good images with no dot reproducibility or voids. The mixing ratio is 2 to 20% by weight of the toner, preferably 3 to 15% by weight, more preferably 4 to 12% by weight. If the toner mixing ratio is less than 2% by weight, the amount of toner charge will increase, making it impossible to obtain sufficient image density;
If it is more than 0% by weight, the interior of the copying machine will be contaminated due to toner scattering, and toner fog will occur on images.

The present invention will be explained below using examples.

Carrier Production Example 1 (1) Preparation of titanium-containing catalyst component In a flask with an internal volume of 500 mQ purged with argon, 200 m+2 of dehydrated n-hebutane was added at room temperature and 120°C in advance.
Add 15 g (25 mmol) of magnesium stearate dehydrated under reduced pressure (2n+mHg) to form a slurry.

After 0.44 g (2.3 mmol) of titanium tetrachloride was added dropwise with stirring, the temperature was started to rise, and the mixture was reacted for 1 hour under reflux to obtain a viscous and transparent solution of the titanium-containing catalyst component.

(2) Activity evaluation of titanium-containing catalyst components In an argon-substituted autoclave with an internal volume II2, 4QQm (i, triethylaluminum 0.8
mmol, 0.8 mmol of diethylaluminium chloride and 0.004 mmol of the titanium-containing catalyst component obtained in (1) above as titanium atoms were collected and introduced.
The temperature was raised to 90°C. At this time, the system internal pressure is 1.5 kg/c
In”G. Next, hydrogen was supplied and 5-5 k
After increasing the pressure to g/cm”c, the total pressure is 9.5 kg
/cIa''G was continuously supplied and polymerization was carried out for 1 hour to obtain 70 polymers.

The polymerization activity was 365 kg/y・T1・Hr, and the MFR (melt flowability at 190°C 1 load 2.I6 to 9: JIs K7210) was 4.
It was 0.

(3) Reaction of titanium-containing catalyst component and filler and polymerization of ethylene Sintered ferrite powder F- dried in dehydrated hexane 500MQ at room temperature and under reduced pressure (2mmHg) at 200°C for 3 hours in an argon-substituted autoclave with an internal volume IQ 200
(manufactured by Powder Chick Co., Ltd., average particle size 70 μm) was added, and stirring was started. Next, the temperature was raised to 40°C, and 0.02 mmol of the titanium-containing polymerization catalyst component (1) was added as titanium atoms, and the reaction was carried out for about 1 hour. Then, 2.0 mmol of triethylaluminum and 2,039 mol of diethylaluminum chloride were added, and 90°
The temperature was raised to C. The internal pressure of the system at this time is 1.5 kg/
It was cm2G. Next, hydrogen is supplied to 2 to 9/cm
After increasing the pressure by 2 Gj, polymerization was carried out for 40 minutes while continuously supplying ethylene so as to maintain the total pressure at 6 kg/cm'G, thereby obtaining a total amount of 473 g of a ferrite-containing polyethylene composition. The dried powder had a uniform gray-white color, and when observed under an electron microscope, the ferrite surface was thinly covered with polyethylene, and no aggregation of ferrite particles was observed in the polyethylene.

In addition, when this composition was measured by TGA (thermal balance), the ferrite content was 95.2 wt%.

Carrier Production Example 2 In a 14-volume autoclave purged with argon, the titanium-containing catalyst component prepared in Production Example 1 (1) was added to 450 g of ferrite in the same manner as in Production Example 1 (3). 0.02 mmol of the solution was added, and the reaction was carried out for 1 hour. Then, add carbon black (Ketchen black D) from the upper nozzle of the autoclave.
J-600, manufactured by Lion Akzo Co., Ltd.) 0.47g was added. Naori-pon black has a temperature of 1 at 200℃
The product was dried under reduced pressure for a period of time and made into a slurry with dehydrated hexane. Then 2.0 mmol of triethylaluminum, 2.0 mmol of diethylaluminum chloride
．． 0 mmol was added and the temperature was raised to 90'C. The system internal pressure at this time was 1.5 kg/cm'G. Next, hydrogen was supplied and the pressure was increased to 2 kg/cm2G; thereafter, polymerization was carried out for 45 minutes while continuously supplying ethylene to maintain the total pressure at 6 kg/cm2, and a total amount of 469.39 ferrite and carbon black was contained. A polyethylene composition was obtained. The dried powder had a uniform black color, and electron microscopy revealed that the ferrite surface was thinly covered with polyethylene, and the carbon blank was uniformly dispersed in the polyethylene. In addition, this composition was subjected to TGA
The ferrite content was 9 as measured by C thermobalance.
5.9wt%, and calculated from the amount of preparation, 7elite, polyethylene, and carbon black are 24:l:0.0
The weight ratio was 25. Thereafter, it was placed in a hot air stream set at 120° C. and heat-treated for 2.0 hours.

The obtained carrier was classified using a 106 μm sieve to remove aggregates.

Carrier Production Example 3 In the same manner as in Carrier Production Example 1, the titanium-containing catalyst component prepared in (1) of Production Example 1 was added to 450 g of ferrite in an argon-substituted autoclave with an internal volume of IQ. Millimole of Ol was added and the reaction was carried out for 1 hour. After that, a carbon blank (Ketchen black) is added from the upper nozzle of the autoclave.
black) E C, manufactured by Lion Akzo) 0.
50g was added. Naori-pon black is 200°
The product was dried under reduced pressure for 1 hour at C and made into a slurry with dehydrated hexane. Thereafter, 1.0 mmol of triethylaluminum and 1.0 mmol of diethylaluminum chloride were added, and the temperature was raised to 90°C. The system internal pressure at this time was 1.5 kg/C. Next, 37.5 mmol (2.1 g) of 1-butene was introduced, then hydrogen was supplied, the pressure was increased to 97 cm"G, and ethylene was continuously supplied to maintain the total pressure at 6 kg/cm2G. Polymerization was carried out for 28 minutes to obtain a total amount of 467 g of a polyethylene composition containing ferrite and carbon black.The dried powder had a uniform black color, and according to an electron microscope, the ferrite surface was thinly covered with polymer, making it a carbon blank. It was observed that ferrite, polymer,
The carbon black had a weight ratio of 27:I:0.03. Furthermore, the polymer from which ferrite and carbon black were removed was extracted by Soxhlet extraction (solvent, quinolene).
When analyzed by H, it was confirmed that it was a polyethylene copolymer containing 3vt% butene.

Thereafter, it was placed in a hot air stream set at 120° C. and heat-treated for 2.5 hours. The obtained carrier was classified using a 106 μm sieve to remove aggregates.

Carrier Production Example 4 200 parts by weight of ferrite fine powder with a volume average particle size of 0.2 μm and bisphenol type polyester resin (softening point: 123°C, glass transition point: 65°C, AV = 21,
OHV: 43, Mn near 600, Mw: 188400)
30 parts by weight were thoroughly mixed in a Henschel mixer (10Q) and kneaded in a twin-screw extrusion kneader.

The obtained mixture was cooled, coarsely pulverized, and finely pulverized in a /\nmar mill, and then coarse powder and fine powder were removed using an air classifier to obtain particles for forming a coating layer with a volume average particle diameter of 3.5 μm. Ta.

A Henschel mixer (101
2) and mixed and stirred at 200 rpm for 2 minutes to uniformly adhere the child particles around the carrier core material.
. Next, each particle was dispersed and supplied into a heated air stream (320° C.), and instantaneous heating was performed for about 1 to 3 seconds to form a coating layer. To 100 parts by weight of the carrier having this coating layer, 2 parts by weight of the positive charge control agent Gronbase EX (manufactured by Orient Kagaku Kogyo Co., Ltd.) was fixed to the coating layer in the same manner.

This carrier was immersed in 6N HCQ for 2 hours, thoroughly washed with water, and vacuum dried at 60°C for 5 hours to obtain a resin-coated carrier having pores on the surface. The core material filling rate of the obtained carrier was 95.4 wt%.

Carrier Production Example 5 250 parts by weight of ferrite fine powder having a volume average particle diameter of 0.2 μm was added to a thermosetting silicone resin solution (KR-255: manufactured by Shin-Etsu Silicone Co., Ltd.) based on 100 parts by weight of the resin solid content, A coating liquid was prepared by thoroughly dispersing the mixture using ultrasonic waves. Using sintered ferrite powder (F-200: manufactured by Powder Chick Co., Ltd., volume average particle diameter 70 μI + 1) as the core material, the core material was repeatedly coated with a spira coater (manufactured by Okada Seiko Co., Ltd.) so that the core material was coated at 25 wt%. did. Thereafter, the temperature in the system was raised to 150° C. to cure the resin, thereby obtaining a thermosetting silicone resin-coated carrier in which fine ferrite powder was dispersed. This carrier was immersed in 6N HCa for 2 hours, thoroughly washed with water, and vacuum dried at 60°C for 5 hours to obtain a resin-coated carrier having pores on the surface.

The core material filling rate of the obtained carrier was 91.5vt%.

Carrier Production Example 6 An acrylic resin solution with a solid ratio of 2% (Acridec A405: manufactured by Dainippon Ink Co., Ltd.) was used as the coating liquid, and a sintered ferrite powder (F-200: manufactured by Powder Tenok Co., Ltd., volume average particle size 70 μm) was used as the core material. ), and a spira coater (manufactured by Okada Seiko Co., Ltd.) was used to coat the core material in an amount of 1.5%. Thereafter, the temperature in the system was raised to 150° C. to cure the resin, thereby obtaining a thermosetting acrylic resin-coated carrier. The core material filling rate of the obtained carrier was 99. O
It was vt%.

Carrier Production Example 7 A carrier was produced in the same manner as Carrier Production Example 5 except that ferrite fine powder was not added and acid treatment was not performed. The core material filling rate of the obtained carrier was 99
．． It was 0wt%.

Table 1 shows the total pore volume (mQ/g) per 1 g of carrier, total pore volume (CmQ/mQ') per 1 mQ of coating layer, and average pore diameter obtained in Carrier Production Examples 1 to 7. .

Table 1 Note that the total pore volume and average pore diameter of the carrier are values calculated from the measurement results of the carrier pore distribution. The pore distribution of the carrier was determined by mercury porommetry. The measurement was carried out using Poresizer 9310 (manufactured by Takasugi Seisakusho Co., Ltd.), and the contact angle of mercury was 130°, and the surface tension was 484 dyn/cm. The results are shown in FIGS. 4 to 9.

FIG. 4 is a diagram showing the relationship between pore diameter and intrusion volume. The intrusion volume represents the pore volume into which mercury was injected up to the maximum pressure at the time of measurement.

FIGS. 5 to 9 are diagrams showing the relationship between pore diameter and volume fraction. The volume fraction is the ratio of the pore volume within a certain pore diameter range to the total pore volume, expressed as a percentage.

In addition, the core material filling rate (it%), true specific gravity (g/cm), bulk specific gravity (g/cm) of the carriers obtained in Carrier Production Examples 1 to 7 are
cm'), electrical resistance, and specific surface area (m2/g) are shown in Table 2 below.

(Hereafter, margin) Table 2 *6N Value after immersion in MCI2 In addition, specific gravity measurement is ・Electronic balance: Sensitivity 0, 1 mg.

・Vicnometer: A pycnometer with a Gerussac thermometer specified in JIS R3501 (glassware for analytical chemistry), internal volume 50m + 2° ・Thermostatic water tank: Capable of maintaining water temperature at 23±0.5°C.

Measure using a measuring device equipped with the following operating procedures!
=.

■Weigh the mass of the pre-dried pycnometer accurately to the nearest 0.1 mg.

■Fill the pycnometer with sufficiently degassed n-hebutane,
23 After keeping it in a constant temperature water tank at 0.5°C for 1 hour, align the liquid surface accurately with the marked line. Remove from constant temperature water bath,
After completely wiping the outside water, its mass is O, l mg
Weigh accurately to the nearest digit.

■Next, the Pykunome - after clearing the evening sample 10~
Collect 15g and weigh it again to the nearest 0.1 digit,
Determine the mass of the sample by subtracting the result of (2).

■ Gently add 20 to 30 mQ of degassed n-heptane to the pycnometer containing the sample to completely cover the sample, and then gently remove air from the liquid in a vacuum desiccator.

■Next, the n-
Fill with hebutane and keep in a constant temperature water bath at 23±0.5°C for 1 hour. After accurately aligning the surface of the liquid with the marked line, take it out, wipe off the water from the outside, and reduce its mass to 0 or 1.
Weigh accurately to the milligram.

■Specific gravity is calculated using the following formula.

S-a-d/(b-c+a) Here, S: specific gravity a: Mass of sample (g) b: Fill the immersion liquid up to the marked line of the vicinometer. Mass when inserted (9) C: Marked line of the pycnometer containing the sample Mass when filled with immersion liquid up to (g) d: Specific gravity of immersion liquid at 23°C The bulk specific gravity was based on JIS Z2504.

The electrical resistance is measured using a metallic circular electrode with a thickness of 1 mm.

Place the sample so that the diameter is 50 mm, and the mass is 895°4.
g, 20mm diameter electrode, inner diameter 38mm, outer diameter 42mm
A guard electrode was placed on the sample, and the current value after 1 minute when a DC voltage of 500 V was applied was read and converted into the volume resistivity ρ of the sample. The measurement environment was a temperature of 25±1° C. and a relative humidity of 55±5%. Measurements were repeated five times and the average was taken.

The specific surface area was measured by the BET method using nitrogen gas adsorption. The device used was Flowsorb 2300 (manufactured by Takasugi Seisakusho Co., Ltd.).

Toner production example 1 Ingredients Parts by weight: Polyester resin 100 (softening point, 130°C
Carbon black 5 (manufactured by Mitsubishi Kasei Co., Ltd., MA#8) - Dye 3 (manufactured by Sakudogaya Chemical Co., Ltd., Spiron Black TRH) After thoroughly mixing the above materials in a ball mill, The mixture was kneaded on three rolls heated to 140°C. After cooling the kneaded material,
It was coarsely ground using a feather mill and further finely ground using a jet mill. Next, air classification was performed, and the volume average particle size was 8.5μ.
A fine powder of m was obtained.

Next, the surface of the toner was modified by a high-speed air impact method. 100 g of the above fine powder was treated for 5 minutes at a rotational speed of 700 rpm using a hybridization system NH3-1 (manufactured by Nara Kikai Seisakusho Co., Ltd.).

After that, air classification was performed to obtain a volume average particle size of 8.1 μm,
Hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., R974) was added to the toner in an amount of 3% by weight and mixed using a Henschel mixer to obtain a toner.

・Styrene-n-butyl methacrylate resin 100 (softening point, 13
2°C glass transition point, 60°C, carbon black
5 (manufactured by Mitsubishi Kasei Co., Ltd., MA#8) - Dye 5 (manufactured by Orient Chemical Industries, Ltd., S-34) After thoroughly mixing the above materials in a ball mill, they were kneaded on a three-roll roller heated to 140°C. After the kneaded material was left to cool, it was coarsely ground using a feather mill and further finely ground using a jet mill. Next, air classification was performed to obtain a fine powder with a volume average particle diameter of 10.2 μm.

Next, the surface of the toner was modified by a high-speed air impact method. 100 g of the above fine powder was treated for 6 minutes at a rotational speed of 6000 rpm using a hybridization system NH3-I type (manufactured by Nara Kikai Seisakusho Co., Ltd.).

Thereafter, the toner was air classified to have a volume average particle diameter of 1010 μm, and then o.tswt% of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., R974) was added to the toner and mixed using a Henschel mixer to obtain a toner.

Toner production example 3 Ingredients Parts by weight: Polyester resin 100 (softening point, 130
°C; glass transition point, 60 °C, AV25.0HV38) - Carbon black 5 (manufactured by Mitsubishi Kasei Co., Ltd., MA#8) - Dye 3 (manufactured by Orient Chemical Co., Ltd., S-34) The above materials were thoroughly mixed in a ball mill. Thereafter, the mixture was kneaded on three rolls heated to 140°C. After the mixed wire was left to cool, it was coarsely pulverized using a feather mill, and further finely pulverized using a jet mill. Next, air classification was performed to obtain a fine powder with a volume average particle size of 6.0 μm.

Next, the surface of the toner was modified by a high-speed air impact method. 100 g of the above fine powder was treated for 4 minutes at a rotational speed of 8000 rpm using a hybridization system NH31 model (manufactured by Nara Kikai Seisakusho Co., Ltd.).

After that, air classification was performed to obtain a volume average particle size of 5.4 μm,
Hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., R974) was added to the toner in an amount of 5 wt % and mixed using a Henschel mixer to obtain a toner.

Examples 1 to 10 Developers were obtained by combining the carriers obtained in Carrier Production Examples 1 to 5 and the toners obtained in Toner Production Examples 1 to 3 as shown in Table 2. The obtained developer was used in a page printer equipped with a (-) chargeable laminated organic photoreceptor to print a 2×2 dot halftone image on the entire surface of A4 paper at a resolution of 480 dpi. The image quality was evaluated based on the number of white spots (voids) generated at this time. The results are shown in Table 3.

Rank 5 (R, 5) 0 pieces Rank 4 (R, 4), 3 to 5 pieces Rank 3 (R, 3) 8 to 12 pieces Rank 2 (R, 2) 15 to 35 pieces Rank U (R,
l) 4Q or more Comparative Examples 1 and 2 The toners and carriers shown in Table 4 were combined and evaluated in exactly the same manner as in the examples. The results are shown in Table 4.

(Hereinafter, blank spaces) Effects of the Invention A developer consisting of a resin-coated carrier having a large number of pores on the surface and a pulverized toner that has been subjected to a spherical treatment not only has stable charging properties and excellent environmental resistance. Even when applied to reversal development using a laser printer or the like, high-quality images without white spots can be formed.

[Brief explanation of drawings]

1 and 2 are schematic cross-sectional views of the resin-coated carrier of the present invention. FIG. 3 is a schematic cross-sectional view of a conventional resin-coated carrier. FIG. 4 is a diagram showing the relationship between the pore diameter of the surface pores of the carrier and the intrusion volume. FIGS. 5 to 9 are diagrams showing the relationship between the pore diameter and volume fraction of carrier surface pores obtained in each carrier production example. Patent Applicant: Minolta Camera Co., Ltd. Representative Patent Attorney Haka Aoyama 1 famous brush 3 illustrations /

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Claims (1)

[Claims] 1. A developer consisting of a resin-coated carrier having a large number of pores on its surface and a pulverized toner that has been subjected to a spheroidal treatment.