JP2704767B2 - Heat fixing toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a monochromatic copying machine for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc., to a full-color copying machine. The present invention relates to a dry electrophotographic toner.

[Prior Art] Conventionally, many electrophotographic methods have been known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 43-24748. However, in general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed using toner, and if necessary, a transfer material such as paper is used. After the transfer of the toner image to the toner image, the toner image is fixed by heating, pressure or solvent vapor to obtain a copy.

Various methods and techniques have been developed for the final step of fixing the toner image on a sheet such as paper. Currently, the most common method is a pressure heating method using a heating roller.

In the pressure heating method using a heating roller, fixing is performed by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heating roller having a surface formed of a material having releasability with respect to toner while contacting the surface under pressure. . In this method, since the surface of the heating roller and the toner image of the sheet to be fixed come into contact with each other under heating, the thermal efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. Very effective in high-speed electrophotographic copying machines. However, in the above method, since the surface of the heating roller and the toner image come into contact with each other under pressure in a molten state, a part of the toner image adheres and transfers to the surface of the fixing roller, and the toner image re-transfers to the next sheet to be fixed. A so-called offset phenomenon occurs, and the sheet to be fixed may be stained. Preventing toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

That is, at present, it is desired to develop a binder resin for a toner having a wide fixing temperature range and a high offset resistance.

There have been many studies and commercialization of two-color copying machines and full-color copying machines. For example, "Journal of the Institute of Electrophotography" Vol 22, No.1 (1983)
There are reports of color reproducibility and gradation reproducibility as in No. 1, P. 52 (1986).

However, it is not immediately compared with the real thing such as television, photographs, color prints, and full color electrophotographic images that are currently in practical use by those who saw color images processed more beautifully than the real ones Is not always satisfactory.

In full-color electrophotography, multiple developments are performed, and several types of toner layers of different colors are required to be superimposed on the same support. Includes the following items.

(1) In order that the fixed toner does not diffusely reflect light and hinder color reproduction, the toner needs to be in a state of almost complete melting such that the shape of the toner particles cannot be determined.

(2) It must be a binder resin having transparency that does not interfere with the toner layers of different colors under the toner layer.

In this way, for monocolor copying machines, development of a binder resin for toner with a wide fixing temperature range and high offset resistance is desired. For full-color copying machines, not only the fixing temperature range is wide but also the transparency of the resin It is required that the fixing surface becomes flat when fixed.

Further, in recent years, from a mono-color to a full-color copying machine, there have been demands for many things such as a high speed, a short heat-up time of a heating roller, and a reduction in power consumption.

In order to satisfy these requirements, low-temperature fixing is possible and, as described above, the fixing area is wide and excellent in transparency,
It is necessary to use a binder resin for a toner such that the fixing surface becomes flat when fixed.

Here, a method using a pressure fixing toner is also conceivable,
In this method, when used as a full-color toner that reproduces colors by three-color or four-color superposition, the binder resin is not melted, resulting in poor color-mixing properties and a dull image with low saturation. Therefore, in the fixing step, heat must be applied to such an extent that the binder resin can be melted and mixed.

It is possible to lower the melt viscosity of the binder resin for toner only for the purpose of fixing at a low temperature. For example, a method of lowering the molecular weight or the glass transition point of the resin may be mentioned. However, this method deteriorates the storage stability of the toner and causes phenomena such as blocking between toners or fusing to a developing drum or the like.

Further, for the purpose of increasing the fixing temperature of conventional vinyl polymers, JP-A-58-14148, JP-A-58-72948, JP-A-59-174855-6, and JP-A-60-123855. Gazette,
JP-B-52-3304-5, JP-B-57-52574,
JP-B-58-8505 discloses a method using an anti-offset agent.However, this method is auxiliary, and particularly when used as a monocolor toner, the transparency of the toner is impaired. Worse.

Also, JP-A-56-158340, JP-A-58-86558, JP-A-58-203453, JP-A-59-88748, JP-A-59-226358, and JP-A-59-226358 JP-A-60-45259, JP-A-60-45261, JP-A-60-46566,
Japanese Patent Publication No. 60-2411 discloses a binder resin for toner having a low molecular weight component and a high molecular weight component. By using these resins, it was possible to increase the fixing temperature to some extent, but due to the presence of a high molecular weight component such as a gel, the melt viscosity at the time of reduction in crushability and heat kneading becomes too high. There is a problem, and particularly when used as a full-color toner, the smoothness of the fixing surface at the time of fixing is impaired, so that the color mixing property is deteriorated.

That is, fixing is performed at a low temperature, and a fixing temperature range is expanded.
It is extremely difficult to simultaneously satisfy the durability, transparency, and smoothness of the fixing surface.

[Problems to be Solved by the Invention] It is an object of the present invention to provide a novel toner for electronic fixing in which these problems are improved.

That is, an object of the present invention is to provide a heat fixing toner which can be fixed at a low temperature and has a wide fixing temperature range.

Still another object is excellent storage stability and fluidity,
An object of the present invention is to provide a heat fixing toner which does not cause aggregation and has excellent impact resistance.

It is still another object of the present invention to provide a heat fixing toner which has good charging characteristics, has stable chargeability during use, and can obtain a clear and fog-free image.

Still another object of the present invention is to provide a heat fixing toner capable of forming a smooth fixing surface so that the fixed toner does not irregularly reflect light and hinder color reproduction when used as a full color toner. It is in.

Still another object is to provide a heat fixing toner having color mixing properties which does not hinder the toner layers of different colors below the toner layer when used as a full color toner.

[Means and Actions for Solving the Problems] The present invention relates to a toner containing an ABA type block copolymer as a binder resin, wherein the A segment constituting the ABA type block copolymer has a styrene monomer and a methacrylic monomer. Wherein the B segment constituting the ABA type block copolymer is a copolymer synthesized from a styrene monomer and an acrylic monomer, and the A segment copolymer has a glass transition point Tg _A. And the copolymer of the B segment has a glass transition point.
The present invention relates to a heat fixing toner having Tg _B , wherein the glass transition points Tg _A and Tg _B satisfy the following relationship: 25 ° C. ≦ Tg _B <Tg _A ≦ 90 ° C.

The present inventors have found that the reason is as described below.

Conventionally, it is known that block copolymers have a so-called sea-island structure. Naturally, the major component is the sea and the minor component is the island. Therefore, in the ABA type block copolymer, A forms an island and B forms an island.

For example, Japanese Patent Publication No. 57-6585 discloses a resin for pressure fixing toner which is a flexible polymer having a glass transition point of component A of less than 20 ° C. and a glass having a glass transition point of component B of greater than 50 ° C. A method using an ABA type block copolymer is disclosed. At present, the most common fixing method at present is a heating method. In particular, the pressure heating method using a heating roller performs fixing by allowing the toner image surface of the sheet to be fixed to pass through the surface of the heat roller having a surface formed of a material having a releasable property with respect to the toner while being pressed. It is. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the heat efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. It is very effective in electrophotographic copying machines. However, the inside of the apparatus may be heated by heat at the time of fixing.

For this reason, there is a case where an undesired phenomenon that the toner blocks during storage may occur, and the requirement for the blocking is becoming strict. In such heat fixing, a toner obtained by using a resin having a soft polymer having a glass transition point of less than 20 ° C. as a component A is easily blocked in an apparatus, and as a result, the fluidity of the powder is poor and a good image is obtained. Difficult to get.

Further, although fixing is possible as described in the heat fixing, since a soft polymer having a glass transition point of less than 20 ° C occupies the sea portion of the sea-island structure, a high-temperature offset occurs. Therefore, the fixing temperature range is narrow for heating and fixing.

Accordingly, the present inventors have conducted intensive studies and found that, in the sea / island structure of the ABA type block copolymer, by setting the sea and the island to a specific configuration, the low-temperature fixability which does not cause the above-mentioned various problems is obtained. The inventors have invented an excellent toner.

In other words, in the sea / island structure, the A segment, which is the sea, has blocking resistance and high temperature offset resistance, and the B segment provides low temperature fixability. That is, for the purpose of separating the functions, the monomer composition ratio of the A segment and the B segment is changed, and the A segment and the B segment have different glass transition points (Tg _A , Tg _B ), respectively.
g _B <Tg _A ≦ 90 ° C. With such a configuration,
The toner having excellent low-temperature fixability can be obtained because, due to the structure in which the A segment is a sea and the B segment is an island, B segments having low-temperature fixability, which is generally weak in blocking properties, are individually present as islands. For the anti-blocking property, it is achieved by the A segment which is a continuous phase sea.

On the other hand, at the time of heating at the time of fixing, low temperature fixability is given by the action of the B segment.

Here, since the A segment and the B segment are connected to each other, the A segment and the B segment are different from each other, for example, as in a polymer blend.
It is presumed that the segments interact with each other, so that the high-temperature offset resistance of the A segment and the low-temperature fixability of the B segment are compatible.

Here, if Tg _B is lower than 25 ° C., blocking occurs even if Tg _A is increased, and if Tg _A exceeds 90 ° C., toner fixability deteriorates.

Further, as described above, the glass transition points (Tg _A , Tg _B ) of A and B in the block copolymer are preferably 25 ° C. ≦ Tg _B <Tg _A ≦ 90 ° C., more preferably 30 ° C. ≦ Tg _B <Tg _A ≦ 85
C is more desirable. More preferably Tg _A and Tg _B
Are preferably separated by 10 ° C. or more.

Here, the heat fixing method means a method of fixing by heating, for example, a pressure heating method using a heat roller,
For example, there is a method in which the recording medium is brought into close contact with the heating body through a film while being pressed against the heating body, and fixed.

The A or B copolymer constituting the ABA type block copolymer used in the present invention is synthesized from the following styrene-based and / or acrylic-based and / or methacrylic-based monomers.

Examples of the styrene monomer include styrene, o-
Methyl styrene, m-methyl styrene, p-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,
4-dimethylstyrene, pn-butylstyrene, pt
ert-butylstyrene, pn-hexylstyrene, p
-N-octylstyrene, pn-nonylstyrene, p
-N-decylstyrene, pn-dodecylstyrene, p
Styrene derivatives such as -methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene and p-nitrostyrene.

Acrylic monomers include acrylic acid and methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate And acrylates such as 2-chloroethyl acrylate and phenyl acrylate.

The monomer composition ratio in the copolymer of B is styrene / acrylic = 95/5 to 50/50, preferably 90/10 to 60/40.

Examples of methacrylic monomers include methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Examples include methacrylates such as stearyl and phenyl methacrylate.

Further, the monomer composition ratio in the copolymer of A is styrene / methacrylic = 98/2 to 35/65, preferably 95/5 to 45/65. However, other monomers may be copolymerized within a range that does not affect the present invention.

The binder resin used in the present invention may contain an ABA type block copolymer. However, in order to more effectively exhibit the properties of the block copolymer, the block copolymer is contained in the binder resin. The polymer is at least 30% by weight or more, preferably 50% or more.
It is desirable that the content be at least wt%.

The electrophotographic toner according to the present invention can be used for a one-component system or a two-component system, and a two-component system toner can be applied in a wide range from monocolor to full color.

However, in order to sufficiently exhibit the toner characteristics of the present invention, when used for full color, the number average molecular weight (n) of the ABA type block copolymer used as a binder resin is 1500 to 30,000, preferably 2500. 20,000, weight average molecular weight (w) of 4000 to 50,000, preferably 6000 to 35,000
It is desirable that When used as a one-component type or a monocolor type, the number average molecular weight of the binder resin (
n) is 2500-40000, preferably 3500-20000, and the weight average molecular weight (w) is 20,000-500000, preferably 35000-350,000
It is desirable that

The following are examples of the vinyl-based monomer constituting the binder resin used by being mixed in the present invention.

For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p
-N-butylstyrene, p-tert-butylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-nonylstyrene, pn-decylstyrene, p
-N-dodecylstyrene, p-methoxystyrene, p-
Chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene,
And unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated diolefins such as butadiene and isoprene; halogens such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride. Vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-methacrylic acid
-Butyl, isobutyl methacrylate, n-methacrylate
Octyl, dodecyl methacrylate, methacrylic acid-2-
Α-methylene aliphatic monocarboxylic esters such as ethylhexyl, stearyl methacrylate and phenyl methacrylate; acrylic acid and methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic acid n-octyl,
Dodecyl acrylate, 2-ethylhexyl acrylate,
Stearyl acrylate, 2-chloroethyl acrylate,
Acrylic esters such as phenyl acrylate; maleic acid, maleic acid half ester; vinyl ethers such as 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 compounds such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole and N-vinylpyrrolidone; vinylnaphthalic acid; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; acroleins and the like Is used by polymerizing one or more of them.

The glass transition point of a polymer or a mixture of the polymers synthesized from vinyl monomers other than the block copolymer in the binder resin is 45 ° C. to 85 ° C. in order to exhibit the properties of the block copolymer. Preferably, it is 55 to 70 ° C.

The polymer synthesized from the vinyl monomer may be a generally known method, for example, a method obtained by solution or suspension polymerization using a peroxide as an initiator.

As a method of synthesizing an ABA type block copolymer, JP-A-63-278910, JP-A-64-6013,
Japanese Patent Application Laid-Open No. 64-26619 discloses a method in which a radically polymerizable vinyl monomer is subjected to bulk polymerization or solution polymerization using a polymerization initiator having a dithiocarbamate group by light.

The electrophotographic toner according to the present invention can be applied to either one-component or two-component toner. Therefore, in order to use the toner of the present invention as a one-component toner, a magnetic powder may be contained. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used, and examples thereof include ferromagnetic metal powders such as iron, cobalt, and nickel, and alloys and compounds such as magnetite, hematite, and ferrite. The content of the magnetic powder is 15 to 70% by weight based on the weight of the toner.

In addition, regardless of whether it is a one-component or two-component toner,
Carbon black, titanium white and any other pigments and / or dyes can be used.

For example, when the toner of the present invention is used as a magnetic color toner, CI direct red 1, CI direct red 4, CI acid red 1,
CI Basic Red 1, CI Modern Red 30, C.I.
I. Direct Blue 1, CI Direct Blue 2, CI
Acid Blue 9, CI Acid Blue 15, CI Basic Blue 3, CI Basic Blue 5, CI Modant Blue 7, CI Direct Green 6, CI Basic Green 4, CI Basic Green 6, and the like. Examples of the pigments include graphite, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartrazine lake, red-mouthed graphite, molybdenum orange, permanent orange GTR, pyrazolone orange, and benzidine orange G. , Cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Eosin Lake, Brilliant Carmine 3B, Manganese Purple, Fast Violet B, Methyl Violet Lake, Navy Blue, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue BC, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Final Yellow There is a green G and the like.

When the toner of the present invention is used as a two-component full-color toner, the following may be mentioned.

CI Pigment Red 1 as a color pigment for magenta
2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,21,2
2,23,30,31,32,37,38,39,40,41,48,49,50,51,52,53,54,
55,57,58,60,63,64,68,81,83,87,88,89,90,112,114,12
2,123,163,202,206,207,209; CI Pigment Violet 19, CI Butt Red 1,2,10,13,15,23,29,35 and the like.

The pigment alone may be used, but it is more preferable to use the pigment and the pigment together to improve the sharpness from the viewpoint of the image quality of a full-color image.

Magenta dyes include CI Solvent Red 1,3,
8,23,24,25,27,30,49,81,82,83,84,100,109,121; CI Disperslet 9; CI Solvent Violet 8,13,1
4,21,27, oil-soluble dyes such as CI Disperse Violet 1, CI Basic Red 1,2,9,12,13,14,15,17,18,
22,23,24,27,29,32,34,35,36,37,38,39,40; CI Basic Violet 1,3,7,10,14,15,21,25,26,27,28 And other basic dyes.

CI Pigment Blue 2,
3,15,16,17; CI Bat Blue 6; CI Acid Blue 45
Or a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on a phthalocyanine skeleton having a structure represented by the formula (1).

CI Pigment Yellow as a color pigment for yellow
1,2,3,4,5,6,7,10,11,12,13,14,15,16,17,23,65,73,83;
CI bat yellow 1, 3, 20 and the like.

The amount of the coloring agent used is 0.1 to 100 parts by weight of the binder resin.
60 parts by weight, preferably 0.5 to 50 parts by weight.

Further, the toner of the present invention does not limit the negative charge property and the positive charge property. However, when producing a negative charge toner, a charge control agent is added particularly for the purpose of stabilizing the negative charge property. Is preferred. As the negative charge control agent, for example, a metal complex of an alkyl-substituted salicylic acid (for example, a chromium complex or a zinc complex of di-tert-butyl salicylic acid)
And organometallic complexes such as

When a positively chargeable toner is prepared, nigrosine, a triphenylmethane compound, a rhodamine dye, polyvinyl pyridine, or the like may be used as a charge control agent having a positive charge. When a color toner is produced, a binder resin containing 0.1 to 40 mol%, preferably 1 to 30 mol% of an aminocarboxylic acid ester having a positive charge property such as dimethylaminomethyl methacrylate as a monomer is used. Alternatively, a colorless or light-colored positive charge control agent that does not affect the color tone of the toner may be used. As the positive charge control agent, for example, structural formula (A),
(B) quaternary ammonium salts and the like.

Among the quaternary ammonium salts represented by the structural formulas (A) and (B), the use of the positive charge control agent represented by the structural formulas (A) -1, -2 and (B) -1 is environmentally-friendly. It is preferable because it shows good chargeability with little dependence.

In addition, in the case of using positively charged aminocarboxylic acid esters such as dimethylaminomethyl methacrylate as a resin component of a binder resin in a positively chargeable toner, a positive charge control agent or a negative charge control agent is required. Use according to.

In the case of a negatively chargeable toner, the amount of the negative charge control agent is 0.1 to 15 parts by weight, preferably 0.1 to 100 parts by weight of the binder resin.
5 to 10 parts by weight are desirable.

In the case of not using an aminocarboxylic acid ester such as dimethylaminomethyl methacrylate showing a positive charge property as a resin component in a positively chargeable toner, a positive charge control agent is used in an amount of 0.1 to 100 parts by weight of the binder resin. It is desirable to use 15 parts by weight, preferably 0.5 to 10 parts by weight. When using aminocarboxylic acid esters, if necessary for the purpose of providing good chargeability with less environmental dependence,
It is desirable to use 0 to 10 parts by weight, preferably 0 to 8 parts by weight of the positive charge control agent and / or the negative charge control agent based on 100 parts by weight of the binder resin.

Further, in the toner of the present invention, a fluidity improver may be added for the purpose of improving the fluidity of the toner.

As the flow improver used in the present invention, any one can be used as long as it can be added to the colorant-containing resin particles to increase the flowability before and after the addition.

For example, a fluorine resin powder, that is, fine powder of vinylidene fluoride, fine powder of polytetrafluoroethylene, or the like; or a fatty acid metal salt, such as zinc stearate, calcium stearate, or lead stearate; or a metal oxide,
That is, there are zinc oxide powder and the like; and fine powder silica, that is, wet-process silica and dry-process silica, and treated silica obtained by subjecting the silica to a surface treatment with a silane coupling agent, a titanium coupling agent, silicon oil, or the like.

Preferred flow improvers are fine powders produced by vapor phase oxidation of silicon halide compounds, so-called dry silica or fumed silica,
It is manufactured by a conventionally known technique. For example, it utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl Also, in this manufacturing process, a composite fine powder of silica and another metal oxide is obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide. Is also possible and encompasses them.

The average particle diameter is preferably in the range of 0.001 to 2 μm, particularly preferably 0.002 to 0.2 μm.
It is preferable to use silica fine powder in the range of μ.

Commercially available fine silica powder produced by vapor phase oxidation of a silicon halide used in the present invention includes, for example, those commercially available under the following trade names.

AEROSIL 130 (Nippon Aerosil) 200 300 380 TT600 MOX170 MOX 80 COK 84 Ca-O-SiL M-5 (CABOT Co.) MS-7 MS-75 HS-5 EH-5 Wacker HDK N20 V15 (WACKER- CHEMIE GMBH) N20E T30 T40 DC Fine Silica (Dow Corning Co.) Fransol (Fransil) Further, treated silica fine powder obtained by hydrophobizing silica fine powder generated by gas phase oxidation of the silicon halide. More preferably, the body is used. It is particularly preferable that the treated silica fine powder is obtained by treating the silica fine powder such that the degree of hydrophobicity measured by a methanol titration test shows a value in the range of 30 to 80.

The hydrophobizing method is applied by reacting with silica fine powder or chemically treating with an organosilicon compound that adsorbs a substance.

As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane,
Trimethylethoxysilane, dimethyldichlorosilane,
Methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α
-Chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane,
Triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane,
Dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 siloxane units per molecule with terminal positions For example, dimethylpolysiloxane containing a hydroxyl group bonded to one Si unit may be used for each unit. These are used alone or as a mixture of two or more.

The treated silica fine powder preferably has a particle size in the range of 0.003 to 0.1 μm. Commercial products include Taranox-500 (Talco), AEROSIL R-972
(Nippon Aerosil).

For the positively chargeable toner, positively chargeable silica fine particles may be used in order to not only improve the fluidity but also obtain good chargeability that is less dependent on the environment.

In order to obtain such positively charged silica fine particles, it is preferable to treat them with a coupling agent containing an amino group or silicone oil. As such a treating agent, for example, H ₂ NCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ H ₂ NCH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ H ₂ NCONHCH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ CH _{2 Si (OCH 3) 3 H 3} C 2 OCOCH 2 CH 2 NHCH 2 CH 2 CH 2 Si (OCH 3) 3 H 5 C 2 OCOCH 2 CH 2 NHCH 2 CH 2 NHCH 2 CH 2 CH 2 Si (OCH 3) 3 _{(H 2 CO) 3 SiCH 2} CH 2 CH 2 -NHCH 2 (H 2 CO) 3 SiCH 2 CH 2 CH 2 -NHCH 2 H ₂ CNHCH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ H ₂ N (CH ₂ CH ₂ NH) ₂ CH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ H ₃ C-NHCONHC ₃ H ₆ Si (OCH ₃ ) There are aminosilane coupling agents such as ₃ .

As the silicone oil, an amino-modified silicone oil having a partial structure having an amino group in a side chain represented by the following formula is generally used.

(Here, R ₁ represents hydrogen, an alkyl group, an aryl group, or an alkoxy group, R ₂ represents an alkylene group, a phenylene group, and R ₃ and R ₄ represent a hydrogen, an alkyl group, or an aryl group. The alkyl group, aryl group, alkylene group, and phenylene group may contain an amine, or may have a substituent such as halogen as long as the chargeability is not impaired. An integer is shown.) Examples of such a silicone oil having an amino group include the following.

In addition, the amine equivalent is the equivalent (g /
eqiv) is the value obtained by dividing the molecular weight by the number of amines per molecule.

It is preferable to use these silica fine particles treated with a coupling agent or a silicone oil containing an amino group, after further hydrophobizing them with the aforementioned organosilicon compound.

When the toner according to the present invention is used as a two-component toner, the carrier used at the time of the phenomenon also plays an important role in order to sufficiently exert its effect.

Examples of the carrier used in the present invention include, for example, surface-oxidized or unoxidized iron, nickel, copper, zinc, cobalt,
Metals such as manganese, chromium, and rare earths and alloys or oxides thereof and ferrites can be used. There is no particular restriction on the manufacturing method.

Further, a system in which the surface of the carrier is coated with a resin or the like is particularly preferable in the J / B developing method described above. As the method, any conventionally known method such as a method of dissolving or suspending a coating material such as a resin in a solvent, coating and adhering to a carrier, and a method of simply mixing with a powder can be applied.

The substance fixed to the carrier surface varies depending on the toner material. Examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal complex of ditersharry butylsalicylic acid, styrene resin, and acrylic resin. It is suitable to use one or more of a series resin, polyacid, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake, fine silica powder, fine alumina powder, etc., but it is not necessarily limited thereto.

The amount of the compound to be treated may be appropriately determined so that the carrier satisfies the above-mentioned conditions, but is generally preferably 0.1 to 30% by weight (preferably 0.5 to 20% by weight) based on the carrier of the present invention.

The average particle size of these carriers is 10 to 100μ, preferably 2
It is preferred to have 0-70μ.

A particularly preferred embodiment is a ternary ferrite of Cu-Zn-Fe whose surface is a combination of a resin such as a fluorine resin and a styrene resin, for example, polyvinylidene fluoride and a styrene-methyl methacrylate resin; Fluoroethylene and styrene-methyl methacrylate resin, fluorine-based copolymer and styrene-based copolymer; such as 90:10 to 20:80, preferably a mixture of 70:30 to 30:70, 0.01-5% by weight, preferably 0.1-1
Coated ferrite carrier having the above-mentioned average particle size, in which the carrier particles are coated by weight and are 250 mesh pass, 400 mesh on, and 70 mesh% or more. Examples of the fluorine-based copolymer include vinylidene fluoride-tetrafluoroethylene copolymer (10:90 to 90:10), and examples of the styrene-based copolymer include styrene-2-ethylhexyl acrylate (20:80 to 90%). 80:20), styrene-2-ethylhexyne acrylate-methyl methacrylate (20
To 60: 5 to 30:10 to 50).

The coated ferrite carrier has a sharp particle size distribution, provides favorable triboelectric charging properties to the toner of the present invention, and has the effect of improving electrophotographic properties.

When a two-component developer is prepared by mixing with the toner according to the present invention, the mixing ratio is defined as a toner concentration in the developer.
Good results are usually obtained at 2% to 15% by weight, preferably 4% to 13% by weight. If the toner density is less than 2%, the image density is low and it becomes impractical. If the toner density is more than 15%, fog and scattering in the machine are increased, and the useful life of the developer is shortened.

 The measurement method according to the present invention will be described below.

Measurement of glass transition temperature Tg In the present invention, measurement is performed using a differential thermal analysis measurement device (DSC measurement device), DSC-7 (manufactured by PerkinElmer).

The measurement sample is precisely weighed in an amount of 5 to 20 mg, preferably 10 mg.

Put this in an aluminum pan and use an empty aluminum pan as a reference.
The measurement is performed at normal temperature and normal humidity at a heating rate of 10 ° C./min.

In this heating process, an endothermic peak of a main peak in a temperature range of 40 to 100 ° C. is obtained.

The intersection of the line of the midpoint of the baseline before and after the endothermic peak appears and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

Measurement of Molecular Weight In the present invention, the molecular weight of a chromatogram by GPC (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C, and THF was added to the column at this temperature as a solvent.
(Tetrahydrofuran) is flowed at a flow rate of 1 ml per minute, and a THF sample solution of the resin adjusted to a sample concentration of 0.05 to 0.6% by weight is injected and measured. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Che
mical Co. or Toyo Soda Kogyo Co., Ltd. has a molecular weight of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10
⁵ , 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶
It is appropriate to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

In order to accurately measure the molecular weight region of 10 ³ to 2 × 10 ^6, a plurality of commercially available polystyrene gel columns may be used in combination. For example, Waters' μ-st
yragel 500,10 ³ , 10 ⁴ , 10 ⁵ combination and Showa Denko sh
odex KF-80M, KF-801,803,804,805 combination, KA-8
02,803,804,805 combination or TSKgel made by Toyo Soda
G1000H, G2000H, G2500H, G3000H, G4000H, G5000H, G6000H,
A combination of G7000H and GMH is preferred.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples. still,
All parts are by weight.

Example of resin production Was placed in a glass reaction vessel, the inside of the vessel was sufficiently purged with nitrogen, and the vessel was sealed. A 400 W ultraviolet lamp was placed at a distance of 15 cm from the reactor to react for 15 hours.

A portion was collected after the reaction, and the molecular weight was measured by GPC. The number average molecular weight (n) was 4200 and the weight average molecular weight (
w) 8700 was obtained. Glass transition point (Tg)
Was 43 ° C.

Thereafter, the second-stage polymerization was further performed as follows to obtain an ABA type block copolymer.

After mixing and dissolving these, 15
The polymerization was carried out by irradiating ultraviolet rays for an hour.

After the reaction, the copolymer was purified by reprecipitation using hexane and dried under reduced pressure. According to GPC, n of the copolymer is 145.
00 and w were 32500, and Tg was observed at 43 ° C. and 65 ° C. at two points. The ABA-type block copolymer obtained here is referred to as resin A.

Hereinafter, the resins B to D and the resin E of Comparative Example 1 were used as initiator amounts,
The styrene / n-butyl acrylate ratio was changed to synthesize.

Resin production comparative examples 2 and 3 Using n12500 in a generally known solution polymerization,
A random copolymer having a wg of 30,000 and a Tg of 57 ° C. was obtained. The random copolymer obtained here is designated as resin F (Comparative Example 2).

The same reaction was carried out with the amount of benzoyl peroxide reduced to 5 g to obtain a random copolymer having n23000, w83000, and Tg of 60 ° C. The resin obtained here was G (Comparative Example 3).
And

Example 1 Is melt-kneaded by a roll mill, cooled, coarsely crushed, finely crushed and classified, and then treated with hexamethyldisilazane as a flow improver.
0.5 parts and 0.2 parts of aluminum oxide fine powder were externally added to obtain a toner.

As a carrier, styrene-acryl 2-ethylhexyl-methyl methacrylate (copolymer weight ratio 50:20:30)
Was prepared using a Cu-Zn-Fe-based ferrite carrier coated with 0.5% by weight (average particle size: 45 μm, 250 mesh pass, 400 mesh on: 87% by weight) so that the toner concentration becomes 6.0% by weight.

Using these developers and toners, an unfixed image was developed and transferred only with a Canon full-color copying machine CLC-500, and a fixing test was performed with an external fixing machine.

As a result, the fixing temperature range where color mixing was possible was 125 to 195 ° C.

Using these developers and toners, an image output test was performed on a CLC-500.

As a result, there was no offset to the fixing roll even after printing of 12,000 sheets in the single-color mode, and a full-color image faithfully reproducing the original color chart without fog was obtained. Further, the toner transportability in the copying machine was good and a stable image density was obtained.

Even when an OHP film was used, the transparency of the toner was very favorable.

The toner was allowed to stand in a hot air dryer at 45 ° C. for one day, and the toner was observed for a blocking state. No change was observed, and the toner had good fluidity.

Example 2 and Comparative Example 1 The procedure of Example 1 was repeated except that the resins were changed to B and E, and the results shown in the following table were obtained.

Example 3 Is melt-kneaded by a roll mill, cooled, coarsely crushed, finely crushed, and classified. Further, 0.6 part of positively charged hydrophobized dry silica is externally added as a flow improver to 100 parts of the classified product to form one component. System magnetic toner.

Using this toner, an unfixed image was obtained using a Canon copier NP-4835, and this was subjected to a fixing test using an external fixing machine. As a result, the fixing area was 120 to 205 ° C. Further, an image output test was performed using the toner and the copying machine. As a result, even after 10,000 sheets of printing, there was no offset to the fixing roll at all, and a good image free of fog and unevenness was obtained.

The anti-blocking property was good as in Example 1, but was good.

Example 4 and Comparative Example 3 The same procedures as in Example 3 were carried out except that the resins were changed to D and G, and the results in the following table were obtained.

[Effects of the Invention] According to the present invention, a specific ABA-type block polymer is used as a binder resin, and the high-temperature offset resistance of the A segment and the low-temperature fixing property of the B segment can be compatible. It is a suitable toner.

Claims (2)

(57) [Claims] 1. A toner containing an ABA-type block copolymer as a binder resin, wherein the A segment constituting the ABA-type block copolymer is a copolymer synthesized from a styrene monomer and a methacrylic monomer. The B segment constituting the mold block copolymer is a copolymer synthesized from a styrenic monomer and an acrylic monomer, the A segment copolymer has a glass transition point Tg _A , and the B segment copolymer is glass. Transition point Tg
_B , wherein the glass transition points Tg _A and Tg _B satisfy the following relationship: 25 ° C. ≦ Tg _B <Tg _A ≦ 90 ° C. 2. The heat fixing toner according to claim 1, wherein the glass transition point Tg _A and the glass transition point Tg _B are separated by 10 ° C. or more.