JPH04204750A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain a toner excellent in toner fluidity, electrification rising, electrification uniformity and environmental stability by incorporating developer inorg. fine particles having hydrophobicity distribution. CONSTITUTION:Inorg. fine particles subjected to surface treatment with a hydrophobe so that the particles have a hydrophobicity distribution are incorporated into the toner. The org. particles are silicon dioxide (anhydride), aluminum silicate, zinc oxide, etc., or mixture of these produced by dry or wet method. As for the hydrophobe, various kinds of coupling agents such as silane type, titanate type, aluminum type, zircoaluminate type, silicone oil, etc., can be used. Thereby, the obtd. toner has excellent toner fluidity, electrification rising, electrification uniformity and environmental stability of charges.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a toner for developing electrostatic images for visualizing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

In electrophotography, a cascade development method (United States patent (U.S.
SP) No. 2297691, USP No. 2618552) or magnetic bluff development method (USP No. 2832311)
(No. 37311.46), a touchdown development method using a developer consisting only of toner (USP No. 4121931), a non-magnetic component development method (USP No. 37311.46), etc. Alternatively, an electrostatic charge image can be visualized by reversal development to obtain a high-quality, stable image.

The toner to be applied to these development methods is a thermoplastic resin as a binder, a dye as a charge control agent, a pigment as a coloring agent, a wax as a release agent, etc., and then kneaded, crushed, and classified. Toner particles having an average particle diameter of 4 to 2511 m are used. In general, inorganic fine powders such as silica, titanium oxide, and aluminum oxide are added to impart fluidity to the toner and improve cleaning properties.

These inorganic fine powders are hydrophilic, and as a result, humidity greatly affects the fluidity and triboelectric charging properties of the toner. In order to prevent the effects of such environmental conditions, it is common practice to use a surface treated inorganic fine powder using a hydrophobizing agent to make toner and apply it to developing devices such as copying machines (
USP No. 3720617, Japanese Patent Publication No. 5410344).

As these hydrophobizing agents, general silane coupling agents are used. For example, hydroxyl groups on the surface of silicon dioxide particles are made hydrophobic by reacting with ranol groups derived from a silane coupling agent. Although the degree of hydrophobicity is disclosed in Japanese Patent Publication No. 1-22616, it is not sufficient, and there are problems with charging rise, uniformity, and stability.

Problems to be Solved by the Invention The present invention has been made in view of the above circumstances, and it is possible to create a toner by incorporating inorganic fine powder that has been surface-treated using a hydrophobizing agent so as to have a hydrophobic degree distribution. The present invention has been completed by obtaining a toner which has excellent fluidity, toner charge build-up and uniformity, and excellent environmental stability of charge.

Means for Solving the Problems The present invention relates to a toner for developing electrostatic images characterized by containing inorganic fine particles for a developer having a hydrophobicity distribution.

Examples of inorganic fine particles include silicon dioxide (anhydrous) produced by a dry method or wet method, aluminum silicate, silicates such as silicate, titanium dioxide, calcium alumina carbonate, barium on titanium, zinc oxide, etc. including mixtures thereof.

The average particle size of these inorganic fine particles is 1IIlμIT1~2
μm1 is preferably 51μH to lμI.

In the present invention, inorganic fine particles are subjected to hydrophobization treatment using a hydrophobizing agent so that they have a hydrophobization degree distribution.

As the hydrophobizing agent, various coupling agents such as silane type, titanate type, aluminum type, zircoaluminate type, silicone oil, etc. are used. Examples of silanes include chlorosilane, alkylsilane, alkoxysilane, and silane. Specifically, for example, ・CH,5iCQ3 ・(CHs)as+cffl ・(CHx)ssicQ ・CHs S 1(○cHs)s ・CHs S i(OCHxc Hs)s・(CH5)
3S i(OCHs) ・(CHs)zsi(OCHs)z ・(e Hs)zs 5(OCHtc H3)
z・S i(OCR! CHs)4 ・Si(○CHI)4 ・CHn(H)Si(OCHs)* ・CH5(H)S i(OCHICHs)z・(CH3
), (H)S i(OCHzc H3)・(◎)xs
1(OCHs)z ・◎5i(OCHxCHx)3 ・(◎)2S1(OCHzCHx)z ・◎S i(OCHs)s ・(◎)zsicI2z ・(◎), CH, 5iCQ ・◎5XCQj ・(◎XCHs) SiCI2z ・(CHs')3S iN HS i(CHs)s・C
H3(CHriIts 1(CHsXOCH3)!・CH
3(CHs)+y Si(OCHs)s・CH3(
CHz)rySi(OC*Hi)s・CH3(CHz)
ssi(CHs)zcQ・cH3(cH,),,5i(
cH3), cΩ・CHs(CHx)it S i(CH
s) C et al. CH4 (CH ri 17s 1CQs etc.).

For titanate series, for example, cH (CIH17) O-+r-T i ・[P÷O-C
lsHxt)20H]zCHI OCC
1yH3sI / CH30CC17H31゜CH3-CH-0-Ti+0-P(0-C8H17)2
11 etc. can be mentioned.

For silicone oil type, for example General formula [engineering]: [In the formula, R1 is -C, H, OC, H, ○H1CH.

Cs Hi OC-C-CHz.

CH,OH QsH, OCH* CC1Hs.

CH,OH ] General formula [■].

[In the formula, R2 represents -CH3, -H] General formula [■] [In the formula, R1 represents -CH5, -OCH] General formula [■]

The general formula [vl: R6 [wherein R1 is an argyl group, R6 and R8 are hydrogen, an alkyl group or -R7N H2 (Rl: an alkyl group], and R8 is a methyl group or a methoxy group] can be mentioned. It is not particularly limited.

The following method is used to treat the surface of inorganic fine powder using a hydrophobizing agent. First, a hydrophobizing agent alone or tetrahydrofuran (THF), toluene, ethyl acetate,
The mixture is mixed and diluted using a solvent such as methyl ethyl ketone or acetone, and while the inorganic fine powder is forcibly stirred with a blender, a diluted solution of the coupling agent is added dropwise or sprayed and mixed thoroughly. Next, transfer the obtained mixture to a vat or the like and heat it in an oven to dry it. Thereafter, the mixture is stirred again using a blender to thoroughly crush the mixture. In such a method, each hydrophobizing agent may be used simultaneously. In addition to such a dry method, there is also a wet method in which fine inorganic powder is immersed in a solution containing a hydrophobizing agent and an organic solvent, dried, and crushed.

In addition, the inorganic fine powder was treated with 10
It is preferable to perform heat treatment at 0°C or higher.

In order to perform hydrophobization treatment as described above on inorganic fine particles and impart a distribution of hydrophobization degree, first, a predetermined amount of inorganic fine powder is stirred with a blender, etc., and a hydrophobizing agent or a diluted mixture thereof is dropped or sprayed. etc. and mix thoroughly. Further, a predetermined amount of inorganic fine powder is added and thoroughly stirred. In this way, by adding the inorganic fine powder to the hydrophobizing agent in stages, it is possible to impart a distribution of the degree of hydrophobization.

In the present invention, the degree of hydrophobicity refers to a value calculated from the amount of methanol used as described below.

That is, 50I110 of pure water is placed in a 200m12 beaker, and 0.2g of the sample is added. While stirring, methanol dehydrated with anhydrous sodium sulfate is added from the biuret, and the end point is when almost no sample is observed on the liquid surface.The degree of hydrophobicity is calculated from the amount of methanol obtained by using the downward formula.

(In the formula, C represents the amount of methanol used (cc)) From the above formula, the relationship between the degree of hydrophobicity and the amount of methanol used is as follows.

Hydrophobic Ippi J [-to----Muguji Kozenji Upper Image-Black 1-
≧ku9su10 5.5
The hydrophobicity distribution is determined as follows.

0.2g of sample was placed in a 200mf2 bottle with 50mC of pure water and methanol dehydrated with anhydrous sodium sulfate.
Add the amount corresponding to 0, shake vigorously for 1 minute, let stand for 1 hour, and separate the sample that has sunk. Transfer it to an evaporating dish,
The solution is evaporated to dryness and allowed to cool in a desiccator. Measure the sample (g) after evaporation to dryness, and calculate the "wetting property (%)" using the following formula.
'Measure.

Next, wetting characteristics are measured in the same manner as above using methanol amounts corresponding to hydrophobic degrees of 20.30...90. By graphing the relationship between the degree of hydrophobicity and wetting characteristics, the distribution of the degree of hydrophobicity can be clearly expressed. For example, the distribution of hydrophobic fine particles (a), which will be described later, is shown in FIG.

In the present invention, the hydrophobicity degree (referred to as total hydrophobicity degree) X, (%) at which the wetting property is 100% is 20≦xl≦80.
The fluidizing agent is hydrophobized so that it has a distribution in which the difference (ΔX) between the hydrophobicity degree X when the wetting property is 5% or more and the total hydrophobicity degree X1 is 15% or more. . Add hydrophobicity to inorganic fine powder.

By providing such a distribution, environmental stability, prevention of toner scattering, prevention of fogging, and stability of charging can be achieved. When the total degree of hydrophobicity is less than 20%, the charging property at high humidity is reduced, causing problems such as toner flying and fogging. Products with a total hydrophobicity greater than 80 are difficult to manufacture. Also, if the ΔX magnitude is smaller than 15%,
Charge stability cannot be obtained.

In order to incorporate the surface-treated inorganic fine powder of the present invention into the toner, there is a method (internal addition) in which the inorganic fine powder is simultaneously kneaded and uniformly dispersed inside the toner at the time of toner mixing.

In addition, when producing a toner by a polymerization method, a method can also be used in which fine inorganic powder is added during polymerization so that the fine inorganic powder is incorporated at the same time as the toner is formed. Furthermore, it is also possible to use a method of fixing inorganic fine powder to the toner surface using mechanical shearing force using a hybridization system, mechanofusion system, or the like.

Toners are generally microparticles consisting of at least a binder resin and a colorant, and some are used as two components together with magnetic carrier particles, some are used as a non-magnetic component, and some are toners that contain a magnetic agent inside the toner (magnetic toner). Although there are some types of toners that are used as components, the inorganic fine particles that have been hydrophobized according to the present invention can be applied to any toner.

The amount of inorganic fine particles added to the toner may be the amount normally used depending on whether it is used as one component or as two components, for example, it may be added internally or externally to a two-component developer. In this case, it is used in an amount of 0.05 to 51% by weight, preferably 0.1 to 2% by weight, based on the toner. It can also be used as a blend of more than one type.

As the binder resin used in the toner, various resins such as acrylic resin, polystyrene resin, polyester resin, styrene-acrylic copolymer resin, and epoxy resin are used.

In the case of toner for heat roll fixing, a release agent such as wax is usually added to the toner.

Its purpose is to prevent toner from being offset onto the roller surface during fixing. Generally, low molecular weight polyolefins such as low molecular weight polypropylene and low molecular weight polyethylene are mentioned.

The present invention will be explained in more detail below using Examples.

Hydrophobization Treatment Production Example (a) As a hydrophobization agent, a mixed solution in which 2 g of hexamethyldisilazane was dissolved in log tetrahydrofuran was prepared.

Colloidal silica as inorganic fine particles; Aerosil #20
0 (manufactured by Nippon Aerosil Co., Ltd.) was treated in a dryer at 120'C for 2 hours. Put 20g of it into a high speed mixer and
The above mixture was gradually added over 5 minutes while stirring at 50 rpm.

Furthermore, add 5g of Aerosil #200 and add 3000r
Stirred for p+nIO minutes. The contents were taken out from the mixer, heated in a constant temperature bath at 150°C for 2 hours, and then crushed to produce hydrophobic silica (a) with a hydrophobicity distribution of 50% to 70%.
I got it.

Figure 1 shows the relationship between the degree of hydrophobicity and wetting properties, and shows the distribution of the degree of hydrophobicity.

Hydrophobization degree distribution color - ■ A mixed solution was prepared by dissolving 3 g of dimethyl silicone oil in 10 g of toluene as a hydrophobizing agent.

Anilosil l''-25 (manufactured by Nippon Aerosil Co., Ltd.) was treated as inorganic fine particles at 120°C for 2 hours in a dryer.
5 g was placed in a high-speed mixer, and the above mixture was gradually added over 5 minutes while stirring at 250 Q rpm. Add 15g of Aerosil P-25 to 3000rp+
Stirred for nIO minutes. Remove the contents from the mixer and
After being treated in a constant temperature bath at 200°C for 5 hours, it was crushed to obtain hydrophobic titanium oxide (b) having a hydrophobicity distribution of 30% to 55%.

Figure 2 shows the relationship between the degree of hydrophobicity and wetting properties, and shows the distribution of the degree of hydrophobicity.

Hydrophobization Treatment Production Example (C) A mixed solution was prepared in which 2 g of hydrogen polysiloxane was dissolved in 10 g of toluene as a hydrophobizing agent.

No 'l! & Colloidal alumina RX (manufactured by Nippon Aerosil Co., Ltd.) was treated as fine particles at 120°C for 2 hours in a dryer, and 20g of it was placed in a high-speed mixer and heated at 2500 rpm.
The above mixture was gradually added while stirring at m. Add 20g of colloidal alumina RX to 3000r
pml Stirred for 0 minutes. The contents were taken out from the mixer and heated in a constant temperature bath at 170°C for 5 hours, then crushed to produce hydrophobic alumina (C) with a hydrophobicity distribution of 25% to 60%.
) was obtained.

Figure 3 shows the relationship between the characteristics of the degree of hydrophobicity and shows the distribution of the degree of hydrophobicity.

Hydrophobization treatment production example (d) A mixed solution was prepared by dissolving 1.5 g of dimethyldimethquine silane as a hydrophobizing agent in 15 g of tetrahydrofuran.

Colloidal silica as inorganic fine powder: Aerosil #13
0 (manufactured by Nippon Anilosil Co., Ltd.) was treated in a dryer at 1206C for 2 hours. Put 10g of it into a high-speed mixer, and
The above mixture was gradually added over 5 minutes while stirring at 50 rpm. After the addition, 5 g of colloidal silica #130 was added and stirred at 3000 rpm for 5 minutes, and further 5 g of colloidal silica #130 was added and stirred at 300 rpm for 5 minutes. The contents were taken out from the mixer, heat-treated in a constant temperature bath at 120°C for 2 hours, and then crushed to obtain hydrophobic glue strength (cure) with a hydrophobic degree distribution of 15% to 55%.

FIG. 4 shows the relationship between the degree of hydrophobicity and wetting characteristics, and shows the distribution of the degree of hydrophobicity.

Hydrophobization treatment production example (e) A mixed solution was prepared by dissolving 2.5 g of hexamethyldisilazane as a hydrophobization agent in tetrahydro7ran]Og.

Colloidal particles as inorganic particles, Anilosil #20
0 (13 pieces manufactured by Aerosil) were treated in a dryer at 120°C for 2 hours. Put 25g of it into a high-speed mixer and
Stir at 0 rpm, gradually add the above mixture over 5 minutes, stir at 3000 rpm for 10 minutes, then add 120 rpm.
After treatment for 2 hours in a constant temperature bath at °C, it was crushed to obtain hydrophobic silica (e) with a hydrophobic degree distribution of 75% to 80%.

Figure 5 t: Shows the relationship between the degree of H hydration and wetting properties2, and shows the distribution of the degree of hydrophobicity.

Hydrophobization treatment production example (f) 2.5g of dimethyl silicone oil as a hydrophobization agent
- A mixed solution was prepared by dissolving 10 g of Luyun.

Titanium oxide fine particles MT-150A (manufactured by Teiriki Co., Ltd.) were treated as inorganic fine particles at 120° C. for 2 hours in a dryer. 35 g of the mixture was placed in a high-speed mixer, and the above mixed solution was gradually added over 5 minutes while stirring at 2500 rpm. The mixture was further stirred for 3000 rpm for 0 minutes. The contents were taken out from the mixer, treated in a constant temperature bath at 200°C for 5 hours, and crushed to obtain hydrophobic titanium oxide (f) with a hydrophobicity distribution of 50% to 55%.

FIG. 6 shows the relationship between the degree of hydrophobicity and wetting properties, and shows the distribution of the degree of hydrophobicity.

Hydrophobization Treatment Production Example Compliance Q A mixture of dimethyldichlorosilane Igfr and tetrahydrofuran log was prepared as a hydrophobization agent.

Colloidal silica as inorganic fine particles; Aerosil #1
30 (manufactured by Nippon Aerosil Co., Ltd.) was treated in a dryer at 120°C for 2 hours. Put 25g of it into a high-speed mixer,
The above mixture was gradually added over 5 minutes while stirring at 00 rpm, and further stirred for 3000 rpm.

Remove the contents from the mixer and place in a thermostat at 120℃ for 2 hours.
After being treated for a period of time, it is crushed and the hydrophobicity distribution is 35% to 40%.
% of hydrophobic silica (g) was obtained.

FIG. 7 shows the relationship between the degree of hydrophobicity and wetting properties, and shows the distribution of the degree of hydrophobicity.

Hydrophobizing treatment production example (h) A mixed solution was prepared in which 12 g of octyltrimethoxysilane was dissolved in 7 g of tetrahydrofuran as a hydrophobizing agent.

Colloidal silica #200 (manufactured by Nippon Aerosil Co., Ltd.) as inorganic fine particles was treated in a dryer at 120° C. for 2 hours. 8 g of the mixture was placed in a high-speed mixer, and the above mixed solution was gradually added over 5 minutes while stirring at 2000 rpm. Add 17g of Aerosil #200 and 3000rp.
ml Stirred for 0 minutes. The contents were taken out from the mixer, treated in a constant temperature bath at 120°C for 5 hours, and then crushed to obtain hydrophobic silica (h) with a hydrophobicity distribution of 0% to 70%.

FIG. 8 shows the relationship between the degree of hydrophobicity and wetting properties, and shows the distribution of the degree of hydrophobicity.

Example 1 (Preparation of Toner A) Styrene/n-butyl methacrylate 100 parts by weight rate copolymer resin (number average molecular weight Mn: 6300, My/Mn: 42, softening point: 132°C, glass transition point 260°C)・Carbon black MA48 8 parts by weight (manufactured by Mitsubishi Kasei Corporation) ・Offset inhibitor Viscoel 5 parts by weight 550
P (manufactured by Sanyo Chemical Industries, Ltd.) - Charge control agent Bontron E-813 parts by weight (manufactured by Orient Chemical Co., Ltd.) The above raw materials were mixed in a Henschel mixer.

The mixture was kneaded with a twin-screw extruder and cooled. The kneaded product was coarsely ground, ground with a jet grinder, and classified with an air classifier to obtain a toner of 4 to 20 μm (average particle size: 9.5 μm). . Hydrophobic fine particles (
a) Add 0.2 parts by weight and mix in a Henschel mixer.
00 rpm for 1 minute (the obtained toner is referred to as toner A) (manufacture of carrier) Ingredients: Polyester resin 100 parts by weight (AV
23.0HV40, softening point 123°C, glass transition point 67°C) - Fe-Zn ferrite fine particles 500 parts by weight MFPi (manufactured by TDK) - Carbon black MA#8 2 parts by weight (manufactured by Mitsubishi Kasei) The above materials were mixed into Henschel Thoroughly mixed using a mixer. Next, the mixture was melted and kneaded using an extrusion kneader set at 180°C in the cylinder part and 170°C in the cylinder head part. After cooling the kneaded product, it was coarsely ground and further finely ground using a jet mill. The pulverized product was classified using a classifier to obtain a binder type carrier [I] having an average particle size of 60 μm.

(Developer evaluation) A two-component developer was prepared by mixing 36 g of toner A with 564 g of carrier, and subjected to charging property, environmental performance test, and printing durability test.

Example 2 (Preparation of Toner B) - Polyester resin 100 parts by weight (number average molecular weight Mn: 4800, My/Mn: 2.8, softening point 101°C, glass transition point 63°C) - Copper phthalocyanine pigment L 1ono1 3 parts by weight Part BlueFG-7350 (manufactured by Toyo Ink Mfg. Co., Ltd.) Charge control agent Bontron E-842 part by weight (manufactured by Orient Chemical Co., Ltd.) The above raw materials were treated in the same manner as toner A in Example 1, A toner with a particle size of 10-3 μm) was obtained. 1 part by weight of hydrophobic fine particles (b) per 100 parts by weight of the above toner.
Add 0.2 parts by weight of hydrophobic silica R, -974 (manufactured by Nippon Aerosil Co., Ltd.) and mix in a Henschel mixer at 1200 rpm.
pm+ for 1 minute (the obtained toner is referred to as toner B) (Manufacture of carrier) A styrene-acrylic copolymer (1,5 nia :1.0:0.5) and 20 parts by weight of the butylated melamine resin were diluted with toluene to prepare a styrene-acrylic resin solution with a solid ratio of 2%. Using sintered ferrite powder (F-300; average particle size 50 μm+, manufactured by Powder Tech Co., Ltd.) as a core material, the core material was coated with 3.0% by weight of the solution using a Subira coater (manufactured by Kaida Seiko Co., Ltd.). Spray coat and allow to dry.

After that, it was cured at 140℃ for 3 hours, and then at 170℃ for 4 hours.
After heat treatment for several hours, the electrical resistance value is 4.3xio"ΩCf
A thermosetting acrylic coated carrier [11] of f1 was obtained.

(Developer evaluation) A two-component developer was prepared by mixing 48 g of toner B with 552 g of carrier, and subjected to the same evaluation as in Example 1.

Example 3 (Preparation of Toner C) - 100 parts by weight of styrene/n-butyl methacrylate, both base resin (seven thousand equal parts) Mn: 4500, Mw/Mn: 60, softening point 121°C, glass transition point 60 ℃) ・Carbon black M, 118 8 parts by weight (manufactured by Mitsubishi Kasei Corporation) ・Offset inhibitor Viscoel 5 parts by weight 550P
(manufactured by Sanyo Chemical Industries, Ltd.) - Charge control agent Pontron N-013 parts by weight (manufactured by Orient Chemical Co., Ltd.) The above raw materials were treated in the same manner as in Example 1, and 5 to 25 parts by weight were added.
A toner with a particle diameter of 11.3 μm was obtained.

0.1 part by weight of hydrophobic particles (d) was added to 100 parts of the above toner and mixed for 1 minute at 120 rpm in a Henschel mixer (the obtained toner is referred to as Toner C) (Developer evaluation ) Toner C 36g was prepared in Example 1 using the carrier [
13,564 g to prepare a two-component developer, which was subjected to the same evaluation as in Example 1.

Example 4 - Hydrophobic fine particles (e) were added to 100 tons of toner C of Example 3.
0.5 parts by weight were added and mixed in the same manner as in Example 1. The obtained toner is referred to as Toner D.

(Developer Evaluation) 36 g of Toner D was mixed with 13564 g of the carrier of Example J to prepare a two-component developer, and the same evaluation as in Example 1 was performed.

Inner back chapter ± Hydrophobic fine particles (d) in 100 parts by weight of toner A of Example 1
0.15 parts by weight was added and mixed in the same manner as in Example 1. The obtained toner is referred to as Toner E.

(Developer evaluation) A two-component developer was prepared by mixing 36 g of toner C and 564 g of carrier [1] of Example 1, and subjected to the same evaluation as in Example 2.

Example 6 Hydrophobic fine particles (h) were added to 100 parts by weight of toner A of Example 1.
A toner was prepared in the same manner as in Example 1 by adding 0 and 2 parts. The obtained toner is referred to as Toner I.

(Developer Evaluation) 136 g of toner was mixed with 11,564 g of the carrier of Example 1 to prepare a two-component developer, and the same evaluation as in Example 1 was performed.

Comparative Example 1 Toner C1001i of Example 3 parts l dihydrophobic fine particles (
e) 0.1! A toner was prepared in the same manner as in Example 1. The obtained toner is referred to as toner F.

(Developer Evaluation) 36 g of toner F was mixed with 11,564 g of the carrier of Example 1 to prepare a two-component developer, and subjected to the same evaluation as in Example 1.

Comparative Example 2 Hydrophobic fine particles (f) were added to 100 parts by weight of toner A of Example 1.
A toner was prepared in the same manner as in Example 1 by adding 1 part by weight. The obtained toner is referred to as toner G.

(Developer Evaluation) 36 g of toner G was mixed with 11,564 g of the carrier of Example 1 to prepare a two-component developer, which was subjected to the same evaluation as in Example 1.

Comparative Example 3 Hydrophobic fine particles (g) were added to 100 parts by weight of toner A of Example 1.
A toner was prepared in the same manner as in Example 1 by adding 0.0 and 2 parts by weight.The obtained toner was referred to as Toner 1 (toner 1).

(Developer Evaluation) 36 g of toner H was mixed with 13,564 g of the carrier of Example 1 to prepare a two-component developer, and the same evaluation as in Example 1 was performed.

Evaluation of charging rise property Using a developer prepared from carrier [1] and toners (a) to (h) at a toner mixing ratio of 21i%, Electrophotography Society Journal, Vol. 27, No. 3 (1988) The amount of charge (q) during developer mixing time was measured by the method described in ``Determination of developer charging speed''.

Based on the measured f-t, the relationship between log(qm-q) and t is shown in FIG. Here, qm indicates the saturation (or maximum) charge amount.

In the figure, . represents the average value obtained from toners (A) to (E) and (1), and . represents the average value obtained from toners CF) to (H).

log(qm-q) shows linearity with respect to time,
The magnitude of the charging rise speed can be expressed by the slope. The steeper the slope of the straight line, the faster the charge rises.

! Mourning summer style banquet! Changes in the amount of charge were investigated at a cold temperature of 25° C. and humidity of 50%, a temperature of 0° C. and humidity of 30%, and a temperature of 35° C. and humidity of 85%. The results are shown in Figure 10.

In the example, the range of change in the amount of charge was small, while in the comparative example, the range of change was large. In particular, in comparative example 4, the amount of charge decreased in an environment of a temperature of 35° C. and a humidity of 85%, and toner scattering occurred. .

Printing durability test Example 1.5 and Comparative Examples 2 to 4 were carried out using EP-870Z (manufactured by Minolta Camera Co., Ltd.), and Printing Durability Test Example 3.4 and Comparative Example f! l
l using EP-4300 (manufactured by Minolta Camera Co., Ltd.),
As for Example 2, an EP-5502 (manufactured by Minolta Camera Co., Ltd.) was modified to an oil coating type, and a printing durability test of 400,000 copies was conducted for each. At this time, the amount of charge and image quality (toner scattering) were evaluated. Toner scattering was visually observed and ranked as follows.

O: Almost no toner scattering was observed.

Δ: Slight toner scattering is observed.

(Can be used on the S circumference) ×: There is a lot of toner scattering, and the inside of the copying machine is heavily soiled (unusable for practical use) The above evaluation results are shown in Table 1.

Effects of the Invention - According to the present invention, by adding inorganic fine particles having a hydrophobic degree distribution to a toner, a toner having excellent toner fluidity, charging rise, charging uniformity, and environmental stability can be obtained.

[Brief explanation of the drawing]

FIGS. 1 to 8 are diagrams showing the hydrophobicity distribution. FIG. 9 is a diagram showing the rise property of charging. FIG. 1O is a diagram showing ring stability. Patent applicant: Minolta Camera Co., Ltd. Representative Patent Attorney Aobai Ao (and 1 other person) Figure 9 Time 7 companies Figure 1 Ugly frost degree c%) Chest 2 Hydrophobicity degree (%) Palm 3 Temperature degree (%) Figure 4 Uninformed cruelty (%) Figure 5 Source freezing degree (%) Figure 6 Koshimi Ihigari 1 ('10) Figure 7 Olo No. 8 ('71 Partial water content (%)

Claims (1)

[Scope of Claims] 1. A toner for developing electrostatic images containing a fluidizing agent, characterized in that the fluidizing agent is inorganic fine particles having a hydrophobic degree distribution. 2. The fluidizing agent has a total hydrophobicity X_1 (%) of 20% to 8
0% range, and the difference (ΔX) between the hydrophobicity degree X_2 and the total hydrophobicity degree X_1 when the wetting property is 5% or more is 15
2. The toner according to claim 1, wherein the toner has a hydrophobicity distribution having a difference of % or more.