JPS60117255A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To give superior particle characteristics, superior transfer characteristics, superior triboelectrifiability characteristics, and superior development characteristics by specifying a practical sphericity in a substantially spherical range, number average particle diameter, change rates of number and volume average particle diameters, triboelectrifiability, and specific resistivity. CONSTITUTION:The toner to be used has a Wadell's practical sphericity of 0.95-1.00, and a number average particle diameter of 5-25mum is superior in fluidity and of approximately true spheres, and small in amts. of fine and coarse particles, and therefore, triboelectrication is made uniform, and an image free from fog, scattered small spots, etc., can be obtained. The change rate of particle diameter is controlled to a narrow particle diameter distribution, such as <=50% and <=45% in the cases of number and volume average particle diameters, respectively. It has a triboelectrified amt. of + or -2-5muC/g, and a specific resistivity of 10<11>-10<16>OMEGAcm. As a result, an image is improved, and transferability and development performance are also improved. Disclosure of fine magnetic particles to the surface of each toner particle is prevented by using fatty acid, its metal soap, oxidized wax, or metal wax, and desirable triboelectrifiability and specific resistivity can be retained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic toner for use in electrophotography, electrostatic recording, etc.

Conventional electronic copying law 51 is US time, h No. 2.297, 8
No. 91 in vertical writing, Japanese Patent Publication No. 42-23910 (U.S. Patent No. 3, EIB6,383 Specification) and Japanese Patent Publication No. 43-
;4748 (U.S. Patent No. 4,071.3fi1)
Although a number of methods are known, generally, an electrical latent image is formed on a photoreceptor by various means using a photoconductive substance, and then the electrical latent image is formed on a photoreceptor. Develop the latent image with toner to make it visible, and if necessary,
After a toner image is transferred to a transfer material such as paper, it is fixed by heating, pressure, etc. to obtain a copy.

Various developing methods are also known for making an electrostatic latent image into an ITF image using toner. For example, the magnetic brush method described in US Pat. No. 2,874,083 IjI mll i5,
The cascade development method described in the specification No. 2618552, the powder cloud method and fur brush development method described in the specification 1 of the same No. 22217711,
A number of development methods are known, such as liquid development. Among these developing methods, the magnetic brush method, cascade method, and liquid developing method, which use a developer mainly composed of toner and carrier, have been widely put into practical use.0 All of these methods produce good images relatively stably. However, it has the disadvantages of deterioration of the carrier and fluctuations in the mixing ratio of toner and carrier, which are common to developers.

In order to avoid these drawbacks, various development methods have been proposed that use l-component developers consisting only of l-color.
In most cases, method 1 is similar to method 1, which uses a developer made of magnetic I/N particles.

On the other hand, toner used for developing such electrostatic images has conventionally been prepared by melting and mixing colorants and other sensitizers in a plastic resin and then uniformly mixing the mixture in minutes/ik L, etc. rear,
The solidified product was finely pulverized and classified to produce colored fine particles of a desired particle size. However, as a result of the manufacturing process, most of the toner produced by such a pulverization method has poor iAE mobility, and insulating toner has a low charge amount on the toner particles. It is non-uniform, which causes problems such as unevenness in development and deterioration of image quality. In addition, since it includes steps such as hot kneading, cooling, pulverization, and classification, it requires a large amount of energy and has the drawback of increasing manufacturing costs.

Therefore, in order to overcome these drawbacks of the pulverization method, we developed a method for obtaining colored polymer fine particles by suspension polymerization using inexpensive water as a dispersion medium using the =j' method, which can be used directly as a toner. There are legal toner manufacturing methods (for example, Japanese Patent Application Laid-Open No. 17735X'F), emulsion polymerization methods, or methods for obtaining toners by suspending and dispersing a mixture containing a molten polymer as a main component and cooling it. Proposed. These methods are generally positioned as granulation methods using water as a dispersion medium, (hereinafter referred to as ζ, sometimes simply referred to as [moisture nk method Jk), but the toner produced by these methods requires a pulverization process. Because it is formed without any friction, there is no need for brittleness, and because it is spherical, it has excellent fluidity and friction. It has the advantage of 9. that the F current is uniform.

However, when attempting to obtain an I-ner containing magnetic powder by these methods, poor dispersion of the magnetic powder often occurs. This is because the magnetic powder is hydrophilic and tends to collect at the interface between the dispersed particles and the water dispersion medium, so that the toner particles formed also have magnetic substances gathered on their surfaces.

As a result, it is possible to obtain] ・Although it is expected that the manufacturing cost is low, the spherical shape has good fluidity, and the frictional charging is uniform, it tends to be conductive. Therefore, the transferability tends to deteriorate. Furthermore, image reproducibility due to environmental changes, especially in a high humidity atmosphere, tends to deteriorate.

The object of the present invention is to eliminate the drawbacks of the I-ner method of the moisture 716 method described above, and to solve the problem of
Excellent particle damage resistance such as L property and transfer characteristics, 11 1f
ω for electrostatic image development with faded charging and development characteristics
The aim is to provide printed toner.

A further object of the present invention is to have excellent fine line 111 development and gradation, environmental stability and i! Jaf'1.II for developing electrostatic images with good durability. The purpose is to provide 1u of l.

The toner for developing an electrostatic image of the present invention has been developed to achieve the above-mentioned objective II, and is based on Wardell's practical spherical toner, which is dispersed and granulated in an aqueous dispersion medium. Degree is 0.95-1.00, number average diameter is 5-25Ii,
It is a substantially spherical magnetic toner with a particle diameter change rate of 50% or less on a number basis, a change in a diameter of 45% or less on a volume basis, and a triboelectric charge amount of ±2 to 50 degrees C. /g, and a specific resistance of 1Qll to 1016Ωcm.

That is, the toner of the present invention contains a magnetic material, has a spherical shape and a narrow particle size distribution, and has a suitable band'rIK, amount, and ratio of 4.
1 (Having resistance is considered a 4h symptom.

The present invention will be explained in more detail below. In the following description, "%" and "part" representing the jll-ratio are based on the mold part unless otherwise specified.

Wardell's practical sphericity is expressed by the ratio of the diameter of a circle with an area equal to the projected area of the target particle to the diameter of the smallest circle circumscribing the projected image of the target particle 1', More specifically, it was measured by the following method. That is, an appropriate amount of toner is placed on a sly glass and dispersed so that individual toner particles do not come into contact with each other or overlap.

These toner particles are projected onto a CR'r image 1l- using a Luzex 450 (Japan Recurator 58) at a magnification of 500 times using a microscope. Here, Luzex 450 is
If the individual particles are separated and shifted, we can freely select any particle and measure its projected area.
From this, we can calculate 81 the diameter of a circle whose area is 41 cm. -・Take a photograph of this C11T screen as it is, and plot the diameter of the smallest circle circumscribing the particle's projection. Here, calculations were made for 00 1-ner condyles rl whose 1° configuration was randomly followed, and the average value was taken as "Wardel's practical sphericity."

In addition, the number average diameter is Coal Coo Counter TA-I+,
An aperture diameter of 100 g was used for assaying with a bonostyrene standard sample, and 111+ was determined.

Since the toner according to the present invention is obtained by pulverization without containing any culms, one island 1!1 is not required, and the shape is generally spherical, and the particle size 11 is narrow. Toners with 4N, Wardell practical sphericity of 0.95 to 1.00, and number average diameter of 5 to 25 have excellent IAt dynamics, are almost pearl-like, and are free of fine powder and coarse dust. An image is obtained. In fact, when the sphericity is less than 0.95, the actual 't'
i1. The shape becomes almost amorphous, the fluidity becomes low, and the triboelectric charge becomes uneven.

Development 4. ? Sexuality decreases. If the particle size is less than 5, there will be a lot of fine powder, and the fluidity and developability will decrease, and the fog will be 1.
1 stand up. If it exceeds 25 pL, there will be a large amount of coarse powder, resulting in 1-1 distortion and poor reproduction of fine lines in images.

In addition, the magnetic I-ner of the present invention has a particle size change rate of a number of particles.
It is characterized by having a narrow particle size distribution (50% or less in terms of volume) and 45% or less in terms of volume. Here, the rate of change in particle size is defined as 1 deviation from the standard on a number basis or a volume basis.
Each average value is expressed as a percentage of 1:1.

Furthermore, the magnetic toner of the present invention has a frictional charging ring of ±2-50
g C/ g, specific resistance is l Q 11 ,, l
It is characterized by Q18ΩC■τ1. If the absolute value of the friction band weight is less than 21L C/g, fog will be 1
”Standing images also get worse. Moreover, when it exceeds 50 hC/g, the image quality deteriorates significantly. Specific resistance is 1OL1
If it is less than Ωcm, the transferability becomes a practical problem, and 10
If it exceeds 18 Ωcm, the charge amplification of the toner occurs, resulting in poor developability. Here, the 11111 constant of triboelectric charge 1 black 1 indicates the constant constant measured by a generally known improved method of blow-off. That is, toner and key carrier (iron powder 200 to 300 mesh) are mixed at a ratio of 1:9 to 1:9, and an appropriate amount of this is placed on the second half of a metal mesh of approximately 400 mesh, and only the toner is sucked out from the docker. At that time, the charge remaining on the carrier was measured, and this amount of charge was taken as the amount of charge generated in the removed toner-1-. The measurement environment was a constant condition of 25° C. and 160% RH.

Moreover, the specific resistance was measured by the following method. That is, about 0.5 g of 1・→-1 was solidified using a tablet molding machine,
Diameter 1cm, height 0.3-0.4. Create a sample around cm. Set this number in the resistance measuring device,
Apply voltage toov and read the current value at that time. At this time,
Since the current Ifi deteriorates with time, the current Ifi1 is read one minute after the voltage is applied, and the resistance value is calculated from this value.

The magnetic toner for developing electrostatic images of the present invention is generally obtained by an aqueous dispersion method including suspension polymerization, emulsion polymerization, seed polymerization, melt emuldigon method, etc., but 4! The suspension polymerization method is the most commonly used in practical applications. For more details,
The magnetic material, other additives, and a suitable polymerization initiator are mixed or dispersed, the resulting polymerizable mixture is dispersed in an aqueous dispersion medium, and the polymerization mixture is brought to a % m concentration.

As the binder material for the toner of the present invention, monomers or copolymers of the monomers listed below can be used.

That is, styrene, θ~methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.4
-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, Pn-butylstyrene, p-ter
t-butylstyrene, p-11-hexylstyrene, p
-n-octylstyrene, p-n-nonylstyrene, p
-Styrene and its aA4 forms such as n-decylstyrene and p-n-dodecylstyrene; ethylenically unsaturated olefins such as ethylene, propylene, butylene, and isobutylene; IS! Vinyl halides such as vinylidene chloride, vinyl bromide, and vinyl fluoride; Vinyl esters such as vinyl acetate, vinyl propionate, and vinyl benzene; methyl methacrylate, ethyl methacrylate, propyl methacrylate, and methacrylic acid Isobutyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methano-2-ethylhexyl, methacrylate starate.

α- such as phenyl methacrylate, dimebulaminoethyl methacrylate, diethylaminoethyl methacrylate, etc.
Methylene 1li1 costal group monocarpyl esters; methyl acrylate, methyl acrylate, n-butyl acrylate, inbutyl acrylate, propyl acrylate, n-A-coubour acrylate, dodecyl acrylate, 2-ethylhexyl acrylate , stearyl acrylate,
AcrytL/acid esters such as 2-chloroethyl acrylate and phenyl acrylate; vinyl methyl ether,
Vinyl ethers such as vinyl ethyl nitrogen and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl impropenyl ketone; N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone Examples include N-vinyl compounds such as vinylnaphthalenes: acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide.

As the magnetic material, for example, ferromagnetic metals such as iron, cobalt, and nickel, or alloys and compounds such as magnetite, hematite, and ferrite are used in powder form.

The acid content of the magnetic material is preferably in the range of 15 to 70% of the toner.

Several means can be effectively used to prevent the magnetic particles from being exposed to the toner particle surface and provide a toner having desired triboelectric charging properties and resistivity I1.

For example, fatty acids, their metallic soaps, oxidized waxes or metallic waxes (4) are used. l1l(1lJj r
'* Ii, represented by the general formula RCOOH (where R is 1 hydrogen ignition), 0, and specific examples thereof include capron 1
'l#, Elient Butyric, Caprylic Acid, Pelargon H1
1) Butonic acid.

undecylic acid, lauryl butyric acid, tridecyl listylic acid,
pentadecyl acid, noklumitin, heptadecyl butylene,
stearic acid, nonadecanoic acid, arachidic acid, behenic acid,
Examples include lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, melinosic acid, roughceric acid, oleic acid, stearolic acid, and arachidonic acid.

In addition, as fatty acid metal soaps, in particular, general formula M (00C
R) 3 (where M is a metal, X (is the same as in 1-,
A metal soap represented by n is an integer representing the valence of the metal M is preferably used, and specific examples thereof include bipedal long-chain fatty acids, ltrium, +11 (lead, ) JJ lesium,
l''11 with metals such as aluminum, cadmium, magnesium, etc. is preferably used.

Further, as an example of oxidized wax, acid value <8 (m g
Examples of metal waxes include calcium, barium 11, and the like.

The above-mentioned fatty acids etc. should be added in a range of 0, 2 to 100 parts per 100 parts of magnetic material.
It is preferable to use lO parts, particularly in the range of 0.5 to 5 flJ/.

Prevents exposure of magnetic material to the toner surface and prevents 1γ friction zone.
Another example of adjusting the resistivity as well as the specific resistance is to make the magnetic material hydrophobic in advance by grafting treatment or the like. Grafting treatment is done using magnetism like this!
In the form of coating a one-piece powder, a grafting agent consisting of the monomers described in 2 above alone or in a mixture with a silane having a vinyl group or a titanium cuffing agent is polymerized in the presence of an initiator. It can be obtained by Acts I1
In general, the same monomer as the binder material of the toner is often preferred as the monomer, but the monomer is not limited thereto. Coupling agent with vinyl group (
For It, it is often very difficult to achieve stable grafting. That is, in this case, the reaction of the coupling agent to the magnetic substance and the interaction between the vinyl group of the coupling agent and Qj-! i
Copolymerization with the t-isomer occurs together, resulting in the formation of a polymer graft layer firmly attached to the surface of the magnetic material. Furthermore, a magnetic material simply subjected to titanium coupling treatment or silane coupling treatment is also effective.

'Friction due to the exposure prevention of the magnetic material 4: 'J Den JI
i and several r stages for adjustment of resistivity (JI
)+1 is also effective. In addition, in addition to step I, a carbonized water compound (J
Ijfl may be used.

As the hydrocarbon compound, paraffin, polyolefin, etc. having a carbon number of 6 or more are preferable, such as paraffin wax (No. 11 Mokui 1 oil), paraffin wax (Nikki Wax), micro wax (No. 11 Mokui J oil). , Microcrystalline wax (11 wood wax), PE-130 (
Hoechst), Sangatsu Hiwax ll0P (Mikata Petrochemicals), February Hyfunks 220F (Mikata Petrochemicals), Mikata Hiwax 660P (Mikata Petrochemicals), etc. In particular, kf or paraffin is used. . Hydrogenated polybutadiene is also preferably used.

These hydrocarbon compounds contain 1 to 100 parts per ioo part of the magnetic material.
Preferably, it is used in a proportion of 20 parts.

In addition, when a toner is produced by polymerization, a crosslinking agent such as the following may be present in the polymerizable mixture in addition to each of the two components, and the crosslinking agent may be polymerized to obtain a crosslinked 4a polymer.

Divinylbenzene, divinylnaphthalene, divinyl ether, divinyl sulfone, diethylene glycol dimethacrylate, triethylene glycol diacrylate tacrylate-1, polyethylene glycol dimethacrylate I, diethylene glycol diacrylate, triethylene glycol diacrylate, l.

3-Butylene glycol dimethacrylate-1.,1.

6-hegysanglycol dimethacrylate, neopentyl glycol dimethacrylate, dibropyrin glycol dimethacrylate-1, polypropylene glycol dimethacrylate, 2,2'-bis(4-methacryloxyjethoxyphenyl)propane, 2.2 '-Bis(4-acryloxyjethoxyphenyl)propane, trimethylolpropane trimethacrylate-1, trimethylolpropane triacrylate, tetramedylolmethanetetraacrylate, dibromneopentylglycol dimethacrylate, phthalodiallyl, etc. , general crosslinking agents can be used as appropriate.

These crosslinking agents are used in Use 111. If there are many, the constant 71 property will be poor. In addition, if less 111 is used, properties such as blocking resistance and durability necessary for toner will be poor.
During hot roll fixing, some of the toner is completely imprinted on the paper.
J,! It becomes difficult to prevent the offset phenomenon in which the paper reaches the surface of the roller and transfers to the next sheet.

- 41 of these racks! The IL of use of the II agent is o, oot to 15Φ for the polymerizable mixture.

! Δ% (more preferably 0.1 to 1:,:
%) is better for historical use.

Furthermore, in order to adjust the color tone of the obtained toner, a coloring agent consisting of dyes such as carbon black, phthalocyanine, and pigments can be added as appropriate.

The l-ner of the present invention is generally prepared by mixing the above components (
The 18 I let me,
Preferably, through a polymerization process and granulation (1
1 will be given.

Examples of active agents include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, and carboxymethyl cellulose. , polyacrylic acid and their salts, starch, camargin he 111, zein, casein, phosphobutyric acid, talc, barium sulfate, ben I nitrate, aluminum hydroxide, ferric hydroxide, titanium hydroxide, water It can be used by including lium oxide, silicon oxide, anti-aluminum oxide in the aqueous phase.6 Also, for fine dispersion of the above-mentioned inorganic dispersant, the toner weight 111 is 0.001 to 0. It may also be possible to use a surfactant in the range of 1%. This is the above part 11
It is used to promote the intended action of agents, and examples thereof include sthorium dodecylpensene sulfonate, sthorium tetradecylhk sulfate, sthorium pentadecyl sulfate, sthorium ophglu 4de ff6, and allyl-alkyl sulfonate. - Sodium polyether sulfone, Sourium oleate J1, Sodium laurate, Sourium caprate I1, Sodium caprylate, Sourium caproate J1, Butypotassium stearin, Calciuno oleate 1,3,3-disulfonodiphenylurea -4,4
-diazo-bis-amino-8-naph)-6-sulfonate, ortho-carpoxypenzene-addimethylaniline, 2,2.5.5-teI-ramedel-triphenylmethane-4, Examples include 4-cyasobis-β-naph)-rudisulfonic acid, and others.

” - Processing fine particles obtained by an aqueous dispersion method such as the suspension polymerization method described above by washing, filtration, decantation, and centrifugal branch A, collecting them for 1° and drying them. Accordingly, the toner is 111.

The toner of the present invention may include loading, IL control cutting,
A fluidity modifier may be further mixed (added) and used.

The obtained toner can be applied to all pre-image development methods. For example, two-component development methods such as the cascade method, magnetic brush method, and microtoning method; one-component development methods using magnetic materials such as conductive component development methods and jumping development methods; powder cloud method and fur brush Used in law, etc.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

The above ingredients were heated to 70°C, combined, and the initiator was dissolved in styrene monomer. Furthermore, a container equipped with a TK homomixer (manufactured by Tokushu Kikaku Chogyo Co., Ltd.), which is a high shear mixing device, was heated. Mixing was carried out for approximately 5 minutes while heating the mixture to approximately 60"C.

Separately, add 1000cc of water to fine silica powder (Aero Seal #2)
00) at 5g/l&L, approx. 60℃L: Heat, TK
Add the monomer system listed in 1- to the stirring door of the homomixer, 40
Approximately t II at 0 Orpm! Stir for f. after that,
This mixed system was stirred 111 times using a paddle stirring blade to complete the 1r combination. After removing the dispersant, wash with water, filter, and dry.
I used toner.

The toner subjected to ftP has a number average diameter of 8.5 μm and a number change rate of 46.5% and a change rate of 41.0% for one body J+'7.
Wardell's practical spherical melon was 0.98.

The amount of triboelectric charge of this toner is +25.5 meJ, C/g
and the specific resistance is 3, 2 X l 01'IΩc m
Met.

This toner was put into a PC-10 copying machine (manufactured by Keenon), and 3,000 images were actually produced continuously. As a result, both at the start and after 3000 sheets, the images were good, with good fine line reproducibility and good gradation. Also, the developed toner is 1,000! +1 and the increase in toner weight I11 in the cleaner to calculate the weight of transferred toner, approximately 80% of the developed toner was transferred,
It was found that the transferability was good. Furthermore, this toner was similarly tested in environments of 10° C., 15% and 30° C., 90%, and good results were obtained in both environments. Furthermore, this toner had good fluidity and was easy to supply to the developing machine.

"Blood comparison" The oxidized wax (ASA-30) of the composition of Example 1 was 0.
．． ]-gnar was prepared in the same manner as in Example 1 except that the amount was 5 g. The obtained toner has a number average (¥8.7μm,
The number change rate is 45.0%, the volume change rate is 38.9%,
Wardell's Tenkawa sphericity was 0.97. The amount of triboelectric charge of this toner is +1.31Lc/g, and the specific resistance is 7.
, 2 X I O'ΩCm.

This toner was tested using a PC-10 copying machine in the same manner as in Example 16. As a result, the image quality was poor immediately after the start of copying, and the image quality was poor during continuous image printing.
It was also bad at 55%. Further, in particular, in a high humidity environment of 30°C and 190%, almost no image appeared.

Claims (1)

[Claims] 1. Dispersed and granulated in an aqueous dispersion medium, the practical sphericity of 7-Del is 0.95 to 1.00, and the number average diameter is 5 to 25IL,
This substantially spherical magnetic toner has a particle size change rate of 50% or less on a number basis and a particle size change rate of 45% or more on a volume basis. C/g,I
L resistance or t OII~l O'' 12cm static '+ll: d:j image developing 1/J-2,
1. It was manufactured by suspension polymerization method. A toner for developing an electrostatic free image according to the fourth aspect of claim 1, wherein the toner has a ν characteristic.