JPH03146961A - Toner for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To improve image quality, moisture resistance and durability by processing polymer particles with a specific fluorine-contained silane compd. of a specific compsn. CONSTITUTION:The polymer particles are processed with the fluorine-contained silane compd. expressed by formula, by which the toner for developing electrostatic latent images is obtd. The hydrophobic property of the resulted toner is improved and the hygroscopicity thereof is lower even at and under a high temp. and high humidity. The image density does not, therefore, change even in the event of the high temp. and high humidity. In the formula, (m) is 0 to 10 integer; (n) is 0 to 5 integer; X is a hydrogen or fluorine atom; Y is S or NH; R is 1 to 5C alkyl group or alkoxy group.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dry toner for developing electrostatic latent images.

[Prior art]

Dry toner used for developing electrostatic latent images formed on electrophotographic photoreceptors, electrostatic recording materials, etc. generally has a thermoplastic resin as its main component, and optionally contains a colorant, a magnetic material, and a thermoplastic resin. A toner is obtained by incorporating a polarity control agent, melting and kneading these materials, and then crushing and classifying them. This toner has many advantages such as good colorant dispersibility, so most dry toners are produced by this method.

However, this type of toner has the disadvantage that the particle size of the toner is reduced by pulverization, and the fine toner particles generated by the pulverization cannot be completely removed and remain in the toner.

In addition, since a resin that is relatively easy to crush is used, if it is used as a developer for a long time, it will gradually be crushed, and the toner will be spent on the frictional charging member, causing a change in the amount of toner charge. Filming occurs on the photoconductor, causing background smearing and a decrease in sharpness.

-2- Furthermore, in recent years, toner with small particle size has been required to improve the image quality of copying machines, but a large amount of energy is required during pulverization, making it difficult to efficiently produce toner with small particle size.

Therefore, a method for producing toner using a suspension polymerization method as described in Japanese Patent Application Laid-Open No. 17735/1983 has been proposed.

Toners made by suspension polymerization do not require consideration of pulverizability as in the case of kneaded toners, and therefore resins that do not cause the toner to become pulverized even when used for a long period of time can be used. Furthermore, since the toner is perfectly spherical, it is difficult to be crushed in the developer. Furthermore, it has the advantage of being able to easily produce toner with small particle diameters and achieving high image quality.

However, on the other hand, it has the following drawbacks.

That is, the dispersion stabilizer dispersed in the aqueous phase adsorbs or adheres to the surface of the suspended polymerizable monomer composition.
This prevents particles from coalescing during polymerization.

However, since dispersion stabilizers are generally hydrophilic and hygroscopic, they must be removed from the toner surface after polymerization.

However, it is very difficult to remove the dispersant adhering to the polymer particles, and as a result, when the temperature becomes high and humid, the toner charge amount changes, resulting in changes in image density and background smearing.

Various proposals have been made to improve these phenomena.

Specifically, there are the following patent applications related to improving the moisture resistance of suspension polymerized toners.

JP-A-53-17735 discloses that particles obtained by suspension polymerization are treated with a reactive silane, and JP-A-59-1
No. 52446 treats particles obtained by suspension polymerization with a silane coupling agent or a titanate coupling agent, and JP-A No. 57-53756 treats particles obtained by suspension polymerization with a poorly water-soluble inorganic salt and an anionic amide type surfactant. The invention relates to a toner in which a polymerizable monomer is polymerized in the presence of an agent, and is disclosed in Japanese Patent Application Laid-open No. 6
No. 3-53563 relates to a suspension polymerization method in which washing and filtration are repeated many times when washing is performed by reacting a dispersant with an alkaline solution by 3-4- after granulation and polymerization. Kaisho 6
No. 3-247759 relates to a suspension polymerization method in which a dispersion stabilizer and an ionic substance remaining on a 1-ner surface are brought into contact with a solid surface having ion exchange ability, and JP-A No. 1-137268 relates to a suspension polymerization method in which a dispersion stabilizer and an ionic substance remaining on a 1-ner surface are brought into contact with a solid surface having ion exchange ability. This technology relates to acetalization of polyvinyl alcohol, a dispersion stabilizer, by surface treatment.

Although all of these methods reduce the influence of the dispersion stabilizer remaining on the toner surface, the current situation is that they are not yet sufficiently effective.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner that overcomes the above-mentioned drawbacks.

That is, the object is to provide a toner that has good moisture resistance, good resolution, does not cause background smearing, and has good durability.

〔composition〕

In order to achieve the above-mentioned object, the present inventors conducted extensive research and found that the polymer particles were expressed by the following general formula (where m is an integer of 0 to 10, n is an integer of 0 to 5,
X is a hydrogen or fluorine atom, and each X may be the same or different. Y is S or NH, R is an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and each R may be the same or different. ) It has been found that the above object can be achieved by a toner for developing electrostatic latent images, which is characterized by being treated with a fluorine-containing silane compound represented by the following formula.

The reason why the properties of toner treated with the fluorine-containing silane compound are stable is that the hydrophobicity of the toner surface is greatly increased.
This is thought to be due to less moisture absorption even under high temperature and high humidity conditions.

The particles to be treated with the fluorine-containing silane compound are not particularly limited, but suspension polymer particles obtained by suspension polymerization are preferred, and in particular suspension polymer particles obtained by dispersing a polymerizable monomer and a colorant are preferred. Dispersion and suspension polymerization in an aqueous phase containing a stabilizer is advantageous because the step of coloring the resulting suspended polymer particles can be omitted.

The particles may be in a washed state after completion of suspension polymerization, and may be in an aqueous phase, in a filtered state, or after drying, but it is more preferable that the particles be in a washed state after completion of suspension polymerization. good.

As a treatment method, the fluorine-containing silane compound can be mixed and stirred directly, or spray coated, or mixed with a solvent and spray coated or dip coated. As the solvent in this case, water, methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. can be used.

The amount of these fluorine-containing silane compounds to be used may be such as to cover the entire surface of the toner, but it is more preferably 0.01 to 5.0% by weight based on the toner.

Specific examples of fluorine-containing silane compounds for treating suspension polymerized particles include the following.

(l CF, CF2C CH25i(OCH,)3 CF, (CF2)2C 8(CH2)2Sl(OCH3)3 CF3(C,F2)3C-8 (CH2)2S i (OCH3)3 CF3(CF2)5C 8 (CH2)3S 1(CH3)3 CF3(CF, ), Cs (CH2)481(CH3
)3○ CF3(CF2)sC-8-(CH2), S i (C
H3)31 CF, (CF2)7C s (cH2)3sx(ocHa)a- 8- (9) CF, (CF2)3G S (CH2)281(OC2H5)3CF, (C,
F2)2C-NH-(CH2)2Si(OCH,)3C
F2(CF,), C-NH-(CH,), S i (
OCHz)a(11) CF3(CF2)3C-8-(CH2)2CF2S i
(OCH3)3(12) CF3(CF2)6C-8-(CH,)(CF2)2S
i (QC2H,)3(13) CF, (CF2)7C-8-(CF,), S i
(OCH3).

CF, (CF,), C-NH-(CH2), S i (
CH3).

CF, (CF2), C-NH (CH2)a S l (OCHz)3(15) CF3(CF,)s(CH2), C-8-(CF2),
CH25i (OC21(5)3CF, (CF, ), C-
NH-(CH2), S i (OCH3)3(16) CF3(CF2), C-8-(CF2), S i (o
cH3) aCF3(CF2), C-NH-CC, H2)
2S i (QC2H,)3(17) CF, CF, C-NH-CH, S i (○CH3)z
9 IO- (27) CF, (CF2)3C-NH-(CH,)
2CF2Si(OCH3)30 (28) cFff(CF, ), cNH(CH2
)z(CFJSI(OCzHs)3(29)CF,(C
F,)7C-NH-(CF,),5i(OCH3)3(
32) CF, (CF2), C-NH-(CF2),
5i(OCH3)3 The toner of the present invention is obtained by treating polymer particles with a fluorine-containing silane compound, and when polymerizing these particles, the polymerizable monomer preferably used is a polymerizable unsaturated It has a group, and specifically the following are used.

For example, styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, P-ethylstyrene, 2,
4-dimethylstyrene, p-n-butylstyrene, p-
Styrene derivatives such as tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, methyl acrylate, ethyl acrylate, n-acrylate
Butyl, isobutyl acrylate, propyl acrylate,
n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate,
Dimethylaminoethyl acrylate, diethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylic Wli-2- Acrylic acid or methacrylic acid derivatives such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyl esters such as vinyl acetate and vinyl propionate, acrylonitrile, methacrylonitrile, etc. ~11- 12- Vinyl ethers such as vinyl compounds, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole , N-vinyl compounds such as N-vinylindole and N-vinylpyrrolidone; and vinyl chloride.

These polymerizable monomers may be used alone or in combination.

In order to produce a crosslinked polymer, the following crosslinking agent may be added to the monomer composition for suspension polymerization.

Namely, divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate-1, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate. Methacrylate-1, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis(4-methacryloxyjethoxyphenyl)propane, 2,2'bis(
Common crosslinking agents such as 4-acryloxyjetoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanethe1hera acrylate, dibromneopentyl glycol dimethacrylate, diallyl phthalate, etc. Can be used.

The crosslinking agent is used in an amount of 0.001 to 100 parts of the polymerizable monomer.
It is preferable to use 15 parts (more preferably 0.1 to 10 parts).

If the amount of crosslinking agent is small, the melt viscosity necessary for the toner cannot be ensured, and it becomes difficult to prevent the offset phenomenon in which a portion of the toner adheres to the roller surface.

Furthermore, if the amount of crosslinking agent is too large, the toner will be difficult to melt due to heat, and unless the roller temperature is extremely high, it will be difficult to fix.

13-14- Furthermore, the monomer composition can contain a mold release agent to prevent offset. All known mold release agents can be used, but polyolefin polymers such as low molecular weight polyethylene and polypropylene are preferred.

This low molecular weight olefin polymer is preferably dispersed in the polymerizable monomer together with the colorant used in the present invention.

The mold release agent is usually used in an amount of 1 to 1 per 100 parts of the vinyl monomer.
Preferably, 5 parts are used.

If the amount is less than 1 part, a sufficient mold release effect cannot be obtained and offset occurs on the roller.

If the amount is more than 15 parts, the release agent will be spent on the triboelectric charging member. Furthermore, the fluidity of the toner becomes extremely poor.

As the coloring agent contained in the monomer composition, conventionally known dyes and pigments, carbon black, and pigments such as grafted carbon black obtained by coating the surface of carbon black with a resin can be used.

The colorant is used in an amount of 1 to 30 parts based on 100 parts of the polymerizable monomer.

The dispersion stabilizer is not particularly limited, but the following may be mentioned.

Namely, water-soluble polymers such as polyvinyl alcohol, starch, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, viscosity, and diatom. Soil, metal oxide powder, etc. are used.

It is preferable to use these in an amount of 0.1 to 10% by weight based on water.

In the present invention, the polymerization initiator may be added to the dispersion containing the monomer composition after granulation, but from the point of view of uniformly applying the polymerization initiator to each monomer composition particle, It is preferable to include it in the monomer composition before granulation.

Examples of such polymerization initiators include 2,2'-azo 15-16-bis-(2,4-dimethylvaleronitrile), 2,2'
-azobisisobutyronitrile, 1,1'-azobis(
cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, Examples include peroxide-based polymerization initiators such as oxide, isopropyl peroxycarbonate, 2,4-dichlorylbenzoyl peroxide, and lauroyl peroxide.

If an aqueous phase polymerization inhibitor is included during polymerization, the formation of transparent fine particles at the end of polymerization can be suppressed to a relatively small amount.

Examples of aqueous phase polymerization inhibitors include alkali metal salts, ammonium salts, and magnesium salts of molybdic acid, alkali metal salts of nitrous acid, and alkaline earth metal salts. Examples of halides include potassium bromide, sodium bromide, and iodine. Potassium chloride, sodium iodide, calcium iodide, ammonium iodide, etc., as well as manganese chloride, manganese sulfate,
Examples include calcium chloride, magnesium chloride, potassium ferricyanide, potassium phosphite, and water-soluble nigrosine.

If used in large amounts, suspension polymerization itself will be inhibited.

Therefore, the appropriate amount of addition is 0.01 to 5% by weight of the dispersion medium.

Further, suspension polymerization may be carried out by making the monomer composition contain a polymer that dissolves in the polymerizable monomer.

In this case, the properties of the polymer can be improved in electrical properties and thermal properties, and the viscosity of the monomer composition can be adjusted.

As the polymer that can be used, any commonly known polymer can be used as long as it is soluble in the monomer. For example, polystyrene, styrene copolymer, acrylic resin, rosin,
Modified rosin, phenolic resin, terpene resin, etc. can be used alone or in combination.

The toner of the present invention may be a type of 17 18- magnetic toner containing a magnetic substance. To obtain a magnetic toner, magnetic particles may be added to the monomer composition.

Examples of magnetic materials that can be used in the present invention include powders of ferromagnetic metals such as iron, cobalt, and nickel, and powders of alloys and compounds such as magnetite, hematite, and ferrite. As the magnetic particles, magnetic particles having a particle size of 0.05 to 5 μm, preferably 0.1 to 1 μm are usually used, but when producing a small particle size toner, magnetic particles with a particle size of 0.8 μm or less are used. Preferably, particles are used.

The magnetic particles are contained in an amount of 10 to 60 parts per 100 parts of the monomer composition.
It is desirable that the content of

Further, these magnetic particles may be treated with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, although it depends on the surface area of the magnetic fine particles or the density of hydroxyl groups present on the surface, the amount of surface treatment agent used is usually 5 parts or less (preferably 0.1 to 3 parts) per 100 parts of the magnetic fine particles. Sufficient dispersibility in the polymerizable monomer can be obtained, and the physical properties of the toner are not adversely affected.

The toner of the present invention may contain a polarity control agent if necessary. Polarity control agents that can be used include:

As the negative charge control agent, metal complex salts of monoazo dyes,
Nitrohumic acid and its salts, salicylic acid, naphthoic acid,
Dicarboxylic acids Co, Cr.

There are metal complexes such as Fe, sulfonated copper phthalocyanine pigments, nitro groups, styrene oligomers introduced with halogens, chlorinated paraffins, melamine resins, etc., and the following can be used as the positive charge control agent.

Sumizol Black AR (Sumitakagaku, oil-soluble dye), Oil Black HBB (Orient Kagaku, C, 1,261
50, C, 1, Solvent Black 3), Nigrosine,
Mikeslen Blue R3N (Mitsui Toatsu, C, 1,698
00, C0■, Bat Blue 4), Ceres Blue R (Bayer, C, 1,61500, C, 1, Solvent Blue 8), Bali 719-0 Fast Blue-1605 (Orient Chemical, oil-soluble dye, C
, 1,74180), Oil Blue 2N (Orient Chemical, oil-soluble dye C, L61555), Lurafix Rubin B (manufactured by BASF, C, 1, 11115, C, 1, Disperse Red 1-13), Lurafix Blue FFR
(BASF, C, L61505, C, 1, Disperse Blue 3), Lulafix Pink FF38 (BA
Made by SF, C, 1, 62015, C0■, Disbirds Red 11), etc.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to the following examples, but the present invention is not limited thereto. Note that all parts are parts by weight.

(Production Example 1 of Suspension Polymerized Particles) Styrene monomer 75 parts n-butyl acrylate monomer 25 parts The above polymerizable monomer mixture was dispersed and mixed for 24 hours using a ball mill. 1.5 parts of lonitrile was dissolved.

On the other hand, an aqueous medium was prepared by dissolving 0.3 parts of potassium iodide and 8.0 parts of polyvinyl alcohol in 400 parts of ion-exchanged water. The above monomer composition was added to this, and a TK homomixer (Tokushu Kika Kogyo Department) was used to mix the mixture at 7000 rpm.
Stirred for 0 minutes.

Four of these suspended dispersions were transferred to a separable flask and polymerized for 7 hours under a nitrogen atmosphere at a rotation speed of 9 lrpm and a temperature of 70°C. After the polymerization was completed, the particles produced were repeatedly washed and filtered to collect them. Dry.

The volume average particle diameter of these particles was 7.3 μm.

(I!' + Production Example 2 of Turbid Polymerized Particles) Styrene monomer 80 parts n-butyl acrylate monomer 20 parts chromium-containing azo dye
3 parts of the above polymerizable monomer mixture was dispersed and mixed for 24 hours using a ball mill, and then 1.5 parts of azobisisobutylnitrile was dissolved in this dispersion.

On the other hand, an aqueous medium was prepared by dissolving 0.3 parts of potassium iodide and 8.0 parts of polyvinyl alcohol 21-22-alcohol in 400 parts of ion-exchanged water. Add the monomer composition to this and TK
Using a homo mixer (manufactured by Tokushu Kika Kogyo), 9000r
Stir for 10 minutes at pm.

Four of these suspended dispersions were transferred to a separable flask and polymerized for 7 hours at a rotation speed of 9 Orpm and a temperature of 70° C. under a nitrogen atmosphere. After the polymerization was completed, the particles produced were repeatedly washed and filtered, collected, and dried.

The volume average particle diameter of these particles was 6.1 μm.

(Example 1) 1 part of the fluorine-containing silane compound (8) was spray applied to 100 parts of the toner obtained in Production Example 1, and then stirred for 30 minutes at 1500 rpm using a Henschel mixer.

This toner was dried under reduced pressure at 50° C. for 5 hours to obtain a toner treated with a fluorine-containing silane compound. Three parts of this toner was added to 100 parts of a spherical ferrite carrier coated with a silicone resin and having an average particle diameter of 100 μm, and the mixture was stirred in a ball mill pot for 30 minutes to obtain a developer. Using this developer, high temperature (30℃, 85%) and low temperature and low humidity (10
℃, 15%) under an environment of F T 5510 manufactured by Ricoh
When image printing was performed using the following methods, a sharp image with high single image density and no background smudge was obtained in any environment.

The amount of charge in both environments was almost unchanged: high temperature and high humidity - 17.9 μc/g, and low temperature and low humidity - 18.9 μc/g.

Further, when a 10,000 copy test was conducted at room temperature and humidity (20°C, 65%), the initial high image quality was maintained even after 10,000 copies, and there was almost no change in the amount of charge.

(Example 2) A toner was produced in the same manner as in Example 1, except that the fluorine-containing silane compound (28) was used instead of the fluorine-containing silane compound (8).

Hereinafter, a developer was prepared in the same manner as in Example 1.

An environmental test and continuous copy test were conducted using FT5510.

As shown in Table 1, the results were extremely good in both moisture resistance and durability.

23-24 (Comparative Example 1) The particles obtained in Production Example 1 were stirred for 30 minutes at 1500 rpm using a Henschel mixer, and then dried under reduced pressure at 50'C for 5 hours to obtain a toner. A developer was prepared using this toner in exactly the same manner as in Example 1, and its moisture resistance and durability were examined.

At low temperatures and low humidity, sharpness was good and image quality was high;
In high temperature and high humidity conditions, sharpness decreased and background smudges also appeared. When the amount of charge of the developer was examined in both environments, as shown in Table 1, the amount of charge was decreased in high humidity.

In addition, although good image quality was obtained initially, as the number of copies increased, background smear became more severe.

(Example 3) A toner was produced in exactly the same manner as in Example 1, except that particles obtained in Production Example 2 were used instead of particles obtained in Production Example 1.

Hereinafter, a developer was prepared in the same manner as in Example 1, and FT551
An environmental test and a 20,000-sheet copy test were conducted using 0.

As shown in Table 1, the results were very good in both moisture resistance and durability.

(Example 4) A toner was produced in exactly the same manner as in Example 2, except that particles obtained in Production Example 2 were used instead of particles obtained in Production Example 1.

Hereinafter, a developer was prepared in the same manner as in Example 1, and tested in exactly the same manner as in Example 3.

As shown in Table 1, the results were extremely good in both moisture resistance and durability.

(Example 5) One part of the fluorine-containing silane compound (24) was dispersed in 50 parts of methyl alcohol, and 100 parts of the particles obtained in Production Example 2 were spray-coated. This was dried under reduced pressure at 50° C. for 8 hours to obtain a fluorine-containing toner.

Using this toner, a developer was prepared using the same method as in Example 1, and the same tests as in Example 1 were conducted.

As shown in Table 1, the results were extremely good in both moisture resistance and durability.

5-26- (Comparative Example 2) A toner was produced in exactly the same manner as in Comparative Example 1, except that particles obtained in Production Example 2 were used instead of particles obtained in Production Example 1.

A test was conducted using this toner in the same manner as in Example 3.

The initial image at room temperature and humidity had good sharpness and high quality, but as shown in Table 1, it was not moisture resistant.

Durability was also not good.

(The following is a blank space) 27- [Effects] The toner of the present invention has improved moisture resistance and durability, and was able to achieve even higher image quality.

29- 28-

Claims (1)

[Claims] 1. Polymer particles are defined by the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, m is an integer of 0 to 10, n is an integer of 0 to 5,
X is a hydrogen or fluorine atom, and each X may be the same or different. Y is S or NH, R is an alkyl group or an alkoxy group having 1 to 5 carbon atoms, and each R may be the same or different. ) A toner for developing electrostatic latent images characterized by being treated with a fluorine-containing silane compound represented by: