JPH01105962A - White toner - Google Patents

Abstract

PURPOSE:To improve the hiding characteristics, scattering preventing property, weather resistance and cleanability of a toner by incorporating aluminum oxide and silicon dioxide. CONSTITUTION:A white toner is composed of a white pigment, a binding resin, aluminum oxide and silicon dioxide. The total amt. of the aluminum oxide and silicon dioxide is 0.1-20pts.wt., preferably 0.5-15pts.wt. per 100pts.wt. binding resin. By using the white toner, a white copied image having satisfactory hiding characteristics is obtd.

Description

[Detailed description of the invention] Industrial applications The present invention relates to toner used in electrophotographic reproduction.

The color of a copy image of conventional electrophotography is generally black, but recently it is also possible to obtain copy images of various colors (color images).

Among color images, white images are formed using white toner on colored paper such as black, and have a different visual beauty from black images. The white toner is composed of a white pigment, a binder resin, and other additives, and when a copied image is formed from the white toner, particularly hiding properties are required. Hiding property is the ability to make the substrate such as paper invisible when toner is fixed on paper. In the case of a black image, even if this hiding property is not so sufficient, the image does not feel blurred enough to be noticeable.
In the case of a white image, even if the hiding property is on the same level as that of black toner, the image feels unclear. Conventional white toners have sufficient hiding properties and cannot produce clear white images that do not give a sense of blur.

In order to improve the hiding properties, it is conceivable to increase the amount of white pigment added to the white toner, but problems caused by increasing the amount of pigment include toner scattering and poor weather resistance. These problems are thought to be caused by poor dispersibility of pigments, but toner scattering can cause fogging on copied images, and poor weather resistance can cause a decline in toner charging properties. .

Furthermore, cleaning defects may occur due to free pigments.

Problems to be Solved by the Invention The main object of the present invention is to provide a white toner that has excellent hiding properties, excellent toner scattering properties, weather resistance, and cleaning properties.

Means for Solving the Problems The present invention relates to a white toner containing aluminum oxide and/or silicon dioxide.

The white toner consists of at least a white pigment, a binder resin, and according to the invention aluminum oxide and/or silicon dioxide.

White pigments include titanium oxide, zinc white, lead white, lead sulfate,
lithopone, zinc sulfide, antimony oxide, lead zinc white, basic sulfate, lead silicate, zircon oxide, barium metaborate, Patchinson's white, manganese white, tin oxide, tungsten white, calcium lead oxide, or mixtures thereof. used.

Particularly in the present invention, titanium oxide is preferred, and titanium oxide may be produced by any method such as a sulfuric acid method, a chlorine method, or a gas phase method. It can also be used in shapes.

The content of the white pigment is 15 to 60 parts by weight, preferably 15 to 50 parts by weight, and more preferably 20 to 40 parts by weight, based on 100 parts by weight of the binder resin described below. If it is less than 15 parts by weight, the hiding properties will be poor, and if it is more than 60 parts by weight, the binding and dispersibility between the pigment and the binder resin will be poor, which will adversely affect toner scattering, capri, fixing properties, etc.

As the binder resin, thermoplastic resin is preferable, and
Examples include monopolymers of styrene and substituted products thereof such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, styrene-p-chlorostyrene copolymers,
Styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer,
Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-(methacrylate) acid) ethyl copolymer, styrene-butyl methacrylate copolymer, styrene-d-methyl chloromethacrylate copolymer, styrene or its substituted monomer, or acrylic acid, methacrylic acid, and its ester monomer. Copolymers with vinyl monomers containing conventionally known amino groups, glycidoxy groups, mercapto groups, ureido groups, 4-treated ammonium groups, nitrogen-containing heterocycles (including quaternized products), and styrene. - Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile - Styrenic copolymers such as indene copolymers, styrene-maleic acid copolymers, styrene-maleic ester copolymers, polymethyl methacrylate, polybutadiene methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene , polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin,
Rosin, modified rosin, terpene resin, phenolic resin,
As the aliphatic resin, alicyclic hydrocarbon resins, aromatic petroleum resins, etc. can be used alone or in combination.

In the present invention, the white pigment and the binder resin further contain aluminum oxide (AQt's) and/or silicon dioxide (SiOy). By doing so, toner scattering properties and weather resistance are improved, and
A white copy image with good hiding properties can be obtained.

The content of aluminum oxide and/or silicon dioxide is 0.1 to 20 parts by weight, preferably 0.1 to 20 parts by weight, per 100 parts by weight of the binder resin.
It is 5 to 15 parts by weight, more preferably 1 to 15 parts by weight. If it is less than 0.1 part by weight, the effects of the present invention cannot be sufficiently obtained, and if it is more than 20 parts by weight, the whiteness will be low.

The white toner of the present invention may further contain additives such as charge control agents, waxes, and the like.

As the charge control agent, either a positive charge control agent or a negative charge control agent can be used.

Among charge control agents, typical ones that impart positive chargeability to toner include amino compounds, quaternary ammonium compounds, alkylamides, phosphorus and tungsten compounds, etc. Typical examples of these compounds include naphthenic acid metal salts, fatty acid metal salts, salicylic acid, reaction products of its derivatives and metal salts, reaction products of its derivatives and metal salts, electron-accepting compounds, etc. can be mentioned. This charge control agent is usually
It is mixed and dispersed in a proportion of 1 to 20 parts by weight per 100 parts by weight of the thermoplastic resin. They can be used alone or in combination of two or more.

As waxes, waxes made of low molecular weight olefin polymers can be used.

The low molecular weight olefin polymer is an olefin polymer containing only olefin as a monomer component or an olefin copolymer containing a monomer other than olefin as a monomer component, and has a low molecular weight.

Examples of low molecular weight olefin polymers include low molecular weight homopolymers, copolymers or modified products thereof, such as low molecular weight homopolymers and copolymers of formula 0 (wherein R is a hydrogen atom or an alkyl group having 4 or less carbon atoms). Molecular weight polyethylene, polypropylene, α or β polybutylene, ethylene-propylene copolymer,
In addition to polyethylene wax, oxidized polyethylene, and chlorinated products, ethylene or propylene is the main ingredient,
Modified with one or more other ethylenically unsaturated monomers such as vinyl acetate, maleic anhydride, acrylic acid or its ester, methacrylic acid or its ester, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, etc. Random copolymers, block copolymers, and graft copolymers with low molecular weights are used.

Other examples include naturally occurring waxes such as vegetable waxes, animal waxes, solid fats, and mineral waxes, as well as fuchses such as higher fatty acids or their derivatives, candelilla wax, carnauba wax, rice wax, Vegetable waxes such as tree wax, palm wax, auriculie wax, sugarcane wax, esparto wax, and park wax; animal waxes such as beeswax, lanolin, and squeeze wax; mineral waxes such as montan wax, oshikerite, and ceresin; and paraffin. Petroleum waxes such as wax, microcrystalline wax and petrolactam, synthetic hydrocarbons such as Fischer-Tropsch wax (Sasol wax), Monk wax derivatives,
Modified waxes such as paraffin wax derivatives and microcrystalline wax derivatives, hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives, derivatives such as 12-hydroxystearic acid, its amides and esters, metal soaps, and high-grade (C, to C72) Amide waxes such as saturated fatty acid amide, unsaturated fatty acid amide and hydroxy fatty acid amide, N-methylene fatty acid amide, N,N'-methylene fatty acid amide, N,N'-ethylene fatty acid amide, dialkyl ketone of higher fatty acid, waxy Fatty acid amines, imides, oils and fats such as glycerides (acylglycerin), -hydric alcohol fatty acid esters, glycerin fatty acid esters, glycol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene fatty acid esters, ethylenes such as phthalate esters, calcium stearate, stearin Alkali metal salts of higher fatty acids such as aluminum acid, magnesium stearate, calcium palmitate, metal salts such as alkaline earth metal salts, zinc salts, aluminum salts, hydrazides of higher fatty acids such as palmitic acid hydrazide, stearic acid hydrazide, etc. acid p-hydroxyanilide, stearic acid p-
p-Hydroxyanilide of higher fatty acids such as hydroxyanilide: β-diethylaminoethyl ester hydrochloride of higher fatty acids such as β-diethylaminoethyl ester hydrochloride of lauric acid, β-diethylaminoethyl ester hydrochloride of stearic acid, stearic acid amide. Synthetic carbonization of higher fatty acid amide-formaldehyde condensates such as formaldehyde condensates, palmitic acid amide-formaldehyde condensates, petroleum residues such as Niassfald and Giltnite, rubbers such as nitrile rubber and chlorinated rubber, Fischer-Tropsch waxes and derivatives, etc. Examples include hydrogen, halogenated hydrocarbons such as chlorinated paraffin and chlorinated propylene, and hydrogenated oils such as hydrogenated castor oil and hydrogenated tallow oil, which can be used alone or in combination with the low molecular weight olefin polymers mentioned above. Used in combination or mixture.

The white toner of the present invention is produced by thoroughly mixing the composition of the above-mentioned main components, then kneading the mixture until it becomes sufficiently homogeneous, cooling it, and using a pulverizer such as a jet pulverizer. The coarse powder and fine powder are removed by pulverization and classification to obtain a white toner having a particle size of 5 to 25 μm and an average particle size of 13 to 14 μM.

In the present invention, aluminum oxide and/or silicon dioxide is sufficiently mixed with a white pigment in advance, aluminum oxide and/or silicon dioxide is immobilized on the surface of the pigment, and by performing the above operations, aluminum oxide It is also possible to prepare toners containing and/or silicon dioxide.

The toner of the present invention may further contain a fluidizing agent (external addition). Glidants include silica, aluminum oxide,
There are titanium oxide, silica/aluminum oxide mixture, silica/titanium oxide mixture, etc.

The white toner of the present invention can be mixed with a suitable carrier to form a two-component developer, for example. As the carrier, when implementing the cascade development method, resin-coated glass beads, sudir balls, etc. are used, and when implementing the magnetic brush development method, ferrite, fine iron powder, or a so-called binder type microcarrier is used. On the other hand, it is also possible to use the valve magnetic toner as the I component by charging it with a developing sleeve or the like.

The present invention will be explained below with reference to Examples.

Example 1 Titanium oxide 25 parts by weight (manufactured by Titanium Kogyo Co., Ltd.; KR-310) AR203 (manufactured by Wako Tsumugi Co., Ltd.) Parts by weight of IO Bontron P-515 parts by weight (manufactured by Orient Kagaku Co., Ltd.) Glass transition point 60°C) Above raw materials After thoroughly mixing with Henschel mixer, 2
The mixture was kneaded using a shaft extruder and then cooled. The kneaded material is roughly pulverized, then pulverized with a jet pulverizer, and then 5 to 25μ by air classification.
(average particle size: 13.5 μm) was obtained.

Thereafter, 0.2 weight room of Aerosil R972 (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd.) was added to form a toner.

Example 2 Titanium oxide 1009 (manufactured by Titanium Kogyo Co., Ltd.; KR-310) A Q 20 z (manufactured by Wako Tsumugi Yakuhin Co., Ltd.),
109 in a Waring blender (ioo
.

Or, p, m for 5 minutes) and A (ho) on the titanium oxide surface.
a was immobilized. Titanium oxide of Example 1, A 12'!
A (hos-treated titanium oxide (25
A toner was produced in the same manner as in Example 1, except that the following was used: (parts by weight).

Example 3 Titanium oxide 25 parts by weight (manufactured by Titanium Kogyo Co., Ltd.: KR-3'l0) SiOz (manufactured by Wako Tsumugi Co., Ltd.) 10 parts by weight Polyester resin 100 parts by weight (softening point 123°C; glass transition point 65°C ) A toner was produced using the above raw materials in the same manner as in Example 1. The above resin was synthesized as follows.

Polyquine propylene (2,2)-2,2-bis(4-
490 g of polyoxyethylene(2,0)-2,2-bis(4-hydroxyphenyl)propane, 216 g of terephthalic acid, 1429 g of n-dodecynylsuccinic acid. Add 0.05 g of dibutyltin or more to a thermometer, stainless steel stirrer,
I equipped with a flowing down condenser and nitrogen inlet pipe
Pour into a Q40 flask and heat to 270 with a mantle heater.
The temperature was raised to °C and the reaction was carried out in a nitrogen stream. When water stopped flowing out, 759 grams of trimellitic acid was added to further advance the reaction, and when the acid value reached 30 x gK OHI3, the reaction was stopped by cooling.

The acid value of the obtained polyester was 30 uKOH/9, and the hydroxyl value was l 2 x gK OHI3. Also,
The viscosity in a flow tester was Tm: 123°C.

Example 4 Example 3 except that Al2aO35 heavy insect part was added to Example 3.
A toner was prepared in the same manner.

Example 5 Titanium oxide (A-200 manufactured by Ishihara Sangyo Co., Ltd.) 25 parts by weight Act x o s (manufactured by Wako Tsumugi Yakuhin Co., Ltd.)
The same procedure as in Example 1 was carried out using 10 parts by weight or more of the raw materials,
A toner was produced. Note that the styrene-dimethylaminoethyl acrylate resin was synthesized as follows.

IQ of 40 Kolben, Styrene (ST) 62.49,
Dimethylaminoethyl methacrylate (DMAM)
After adding and dissolving 62.8 g, 1209 toluene and 3.29 azobisisobutyronitrile (AIBN),
Polymerization was carried out by reacting at 80° C. for 6 hours under a nitrogen stream. Next, after distilling off toluene, 40
Vacuum was applied to ˜50 xiHg to completely remove volatiles. The obtained polymer is a colorless and transparent solid with a glass transition point (T
g) was 56°C and the amine value was 174.

Example 6 30 g of titanium oxide (manufactured by Titan Kogyo Co., Ltd., KR-310)
25 parts by weight of a mixture of Aρ,03 (Wako Pure Chemical Industries, Ltd.) 0.19 mixed in a Waring blender (I 000 Orpm, 5 minutes) was used in place of 25 parts by weight of titanium oxide and 10 parts by weight of AQt03 in Example 1. A toner was prepared in the same manner as in Example 1 except for this.

Example 7 In Example 6, 30 g of titanium oxide and A(bosO,1
A toner was prepared in the same manner as in Example 6 except that 30 g of titanium oxide and 20 g of A (bos) were used instead of g.

Example 8 In Example 6, 30 g of titanium oxide and AQvO30, I
A toner was prepared in the same manner as in Example 6, except that 30 g of titanium oxide and SiO*0.19 were used instead of 30 g of titanium oxide.

Example 9 In Example 6, 30 g of titanium oxide and AQvO 30°I
A toner was prepared in the same manner as in Example 6, except that titanium oxide 309 and 5iO-209 were used instead of g.

Example 1O In Example 6, titanium oxide 309 and A (2t0°0.
Instead of 1g, 30g of titanium oxide and 1tOsO112
A toner was prepared in the same manner as in Example 6 except that 5iOtO and 1 g were used.

Example 2 In Example 6, 30 g of titanium oxide and A Q t O3
Instead of 0.1g, 30g of titanium oxide and Aρ, 031
A toner was prepared in the same manner as in Example 6 except that SiO*10g and SiO*10g were used.

Comparative Example 1 A toner was produced in the same manner as in Example 1 except that A12tO+ was removed from Example 1, and a similar copy image was formed, but the hiding power was low and only a vague image was obtained.

Comparative Example 2 In Example 1, 25 parts by weight of titanium oxide, AQt031
When the same procedure as in Example 1 was carried out except that 60 parts by weight of titanium oxide was used instead of 0 parts by weight, background fogging occurred.

Comparative Example 3 In Example 1, 25 parts by weight of titanium oxide, Al2203
When the same procedure as in Example 1 was carried out except that 65 parts by weight of titanium oxide was used instead of 65 parts by weight of IO, background fogging occurred and the fixing performance was also deteriorated.

Comparative Example 4 In Example 1, titanium oxide 25 weight part, AC3031
The same procedure as in Example 1 was carried out except that 0 parts by weight of titanium oxide IO was used instead of 0 parts by weight, but sufficient hiding power could not be obtained.

Comparative Example 5 In Example I, 25 parts by weight of titanium oxide, AL03IO
Except for using 35 parts by weight of titanium oxide instead of parts by weight,
The same procedure as in Example 1 was carried out.

Comparative Example 6 In Example 1, 25 parts by weight of titanium oxide, ACtO3I
The same procedure as in Example 1 was carried out except that 15 parts by weight of titanium oxide was used instead of parts by weight of O.

Comparative Example 7 In Example 1, 25 parts by weight of titanium oxide, A12203
25 parts by weight of titanium oxide and 1 part by weight of lead sulfate instead of 10 parts by weight
The same procedure as in Example 1 was carried out except that the amount was 0 parts by weight.

Comparative example 8 In Example 1, 25 parts by weight of titanium oxide, AQ.

The same procedure as in Example 1 was conducted except that 25 parts by weight of titanium oxide and 10 parts by weight of zinc white were used instead of 1 part by weight of 0310.

Preparation of carrier (A) Styrene-acrylic copolymer resin (Bryolide AC
L, 00 parts by weight manufactured by Gutdeyer, 200 parts by weight of magnetic powder (Mapico Black 500; manufactured by Methane Industries, Ltd.), 4 parts by weight of carbon black (MA #8; manufactured by Mitsubishi Chemical Industries, Ltd.),
Two parts by weight of silica (#200, manufactured by Nippon Aerosil Co., Ltd.) are mixed in a ball mill and kneaded with three rolls. The kneaded material is pulverized using a pin mill and classified using a wind classifier. Carrier (
A) was obtained.

Preparation of carrier (B) Polyester resin (softening point 123°C; glass transition point 65
°C) 100 parts by weight, inorganic magnetic powder (manufactured by Toda Kogyo Co., Ltd.; EP
T-1000) 500 parts by weight, carbon black (MA
2 parts by weight of #8 (manufactured by Mitsubishi Chemical Industries, Ltd.) were thoroughly mixed and pulverized using a Henschel mixer, and then the cylinder part was heated at 160°C.
The mixture was melted and kneaded using an extrusion kneader whose cylinder head was set at 150°C. After cooling the kneaded material, it was finely pulverized using a jet mill, and then classified using a classifier to obtain an average particle size of 5.
A 5 μm magnetic carrier (B) was obtained.

The powder electrical resistivity of the obtained carrier was 7.08x l
Q: It was 13Ω. Applied magnetic field of this carrier 10
The magnetic flux density Bm at the source of 000e is l082G, and the amount of magnetization σ
is 45,6 emu/g, residual magnetization Hc is 217.6
It was G.

Preparation of carrier (C) In addition to the carriers (A) and (B) above, ferrite coated carrier (C)...average particle size 62μ, electrical resistance 5
XIO"Ω-cmc 100 V 7cm) was used.

Toner evaluation examples 1 to 11. The white toner obtained in Comparative Examples 1 to 8 and carriers (A), (B), and (C) were mixed at a toner mixing ratio of 1.
A developer was prepared at 0 wt %, and the amount of toner charge was measured. The results are shown in Table 1.

Furthermore, using carrier (A), a copy image was formed on transfer paper using EP450Z or EP550Z (manufactured by Minolta Camera Co., Ltd.), the hiding power was evaluated, and the to
Continuous copying of 00 sheets was performed, and changes in hiding power, toner charge amount, and background fog were observed at the initial stage and after 10,000 copies were made.

In addition, in the initial stage, the prepared developer should be used under high temperature and high humidity (
The sample was left at 35°C (385%) for 2 days, and the change in the amount of charge thereafter was measured. The results are shown in Table 2.

The hiding power and background fog in Table 2 were evaluated and ranked as follows.

The hiding power is the ability to make the substrate invisible when toner is fixed on the substrate. There are various methods for measuring the hiding power, but it was evaluated based on the congratulatory reflectance when toner was fixed on black paper (reflectance of 8% or less).

The concealing power of white toner is less than 20% with congratulatory reflectance.
20% or more was marked as ○.

Background fog The background fog due to toner scattering was visually observed as ○ if it was good, △ if it was somewhat good, and X if it was bad.

Table 1 Effects of the Invention According to the present invention, by incorporating aluminum oxide and/or silicon dioxide into a white toner, a white toner with excellent hiding properties, no toner scattering, and excellent weather resistance can be obtained.

Patent applicant: Minolta Camera Co., Ltd.

Claims (1)

[Claims] 1. White toner containing aluminum oxide and/or silicon dioxide.