JPH10161341A - Capsulated toner for heat roll fixation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner having superior electrostatic chargeability even in the case of an electrophotographic toner not using an electrostatic charge regulating agent or using a reduced amt. of the agent. SOLUTION: The surface of a toner contg. magnetic powder and carbon black having <=pH7, 90-200m<2> /g BET specific surface area and 50-110ml/100g DBP oil absorption by 0.1-5 pts.wt. and 2-10 pts.wt., respectively, based on 100 pts.wt. fixing resin contg. at least styrene and maleic monoester and/or fumaric monoester monomers as constituents is treated with a silicon- and/or titanium-contg. material showing <=pH7 in the form of 4% soln. in water- methanol and having 80-300m<2> /g BET specific surface area to obtain the objective toner for a two-component magnetic developer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capsule toner used for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic printing method, an electrostatic recording method, etc., and more particularly to a capsule toner for fixing with a heat roller. Things.

[0002]

2. Description of the Related Art In an electrophotographic method, for example, an electrostatic latent image is usually formed on a latent electrostatic image carrier made of a photoconductive photoreceptor by charging and exposure, and then the electrostatic latent image is colored. The toner image is developed with particles, and the obtained toner image is transferred to an image support such as transfer paper, and then fixed by heat or pressure to form a visible image.

Conventional methods for fixing a toner image include:
A method in which a toner is heated and melted in a non-contact state with a heater, a method in which a toner is dissolved and fixed with an organic solvent, a method in which a toner is pressed and fixed, and a method in which a heat roller is brought into direct contact with a toner and melted A so-called heat roller fixing method for fixing by pressing is known, but a heat roller fixing method is widely used because of its high thermal efficiency and high-speed fixing.

However, at the latest, (I) suppression of overheating deterioration of the copying machine, and (II) warm-up time required for raising the temperature of the heat roller to a temperature at which the heat roller can be fixed after operating the heat roller fixing device. (III)
Minimizing the temperature drop of the heat roller due to the absorption of heat by the image support such as transfer paper to enable stable continuous image formation many times; (IV) miniaturization of copiers and From the viewpoint of improving safety, it is strongly demanded that the power consumption of a heater incorporated in a fixing device be reduced so that a fixing process can be performed with the temperature of a heat roller lowered.

Accordingly, the toner is required to: (1) be able to achieve good fixing at a lower temperature, that is, to have excellent low-temperature fixing properties; is required. (2) In the heat roller fixing method, which is preferable as a fixing method, a part of the toner constituting the image is transferred to the surface of the heat roller at the time of offset development, that is, fixing, and is transferred again to the next transfer paper. Since the phenomenon that an image is stained is apt to occur, the toner is required to have a property that is less likely to be transferred to a heat roller, that is, to provide an offset resistance. (3) It can be stably present as a powder without agglomeration under conditions of use or storage environment, that is, it has excellent blocking resistance. (4) The toner has good triboelectricity, and the developing process, the transferring process, and the cleaning process are performed well, and a clear image without fog can be obtained. (5) The occurrence of a so-called filming phenomenon in which the toner substance adheres to the surface of the photoreceptor or the surface of the carrier particles is suppressed, and the image can be stably formed many times.

However, conventionally, there has been proposed a technique for achieving low-temperature fixability by using a capsule toner composed of core material particles and an outer shell provided so as to cover the surface of the core material particles. Have been.
In this type of capsule toner, a low melting point compound or a material having a low Tg is used as the core material particles in order to improve the melting property at a low temperature. Specifically, the following technology is disclosed. A technique in which core material particles are composed of wax (see Japanese Patent Publication No. 49-1588).

A technique in which core particles are composed of a polyester crosslinked with a polyvalent metal compound (Japanese Patent Laid-Open No. 58-17 / 1983)
No. 4957). A technique in which core particles are composed of low-melting polyester (see JP-A-58-176652).

[0008] A technique in which the core particles are composed of a low molecular weight styrene-acrylic resin having a gel fraction of 20 to 70% (see Japanese Patent Application Laid-Open No. 58-176463). A technique in which core particles are made of amorphous polyester having a Tg of 60 ° C. or lower (see Japanese Patent Application Laid-Open No. 58-205161).

A technique in which the core particles are composed of a crosslinked vinyl copolymer having a Tg of 55 ° C. or less and a gel fraction of 20% or more (see Japanese Patent Application Laid-Open No. Sho 58-205161).

A technique in which the core particles are made of an amorphous polyester having a Tg of 60 ° C. or less and an acid value (AV) of 10 to 150 (see Japanese Patent Application Laid-Open No. 58-205163).
A technique in which core particles are composed of an amorphous polyester and a polyvalent metal compound (see JP-A-58-205164).

[0011]

However, in the above technique, when the heat roller fixing method is applied as the fixing method, the offset resistance is considerably poor and the practicality is extremely low. Further, in the above technology, under environmental conditions of normal temperature and normal pressure (for example, a temperature of 20 ° C. and a relative humidity (RH) of 60%), although the performance is improved as compared with the above technology, the offset resistance is not good. However, there is a problem that the fixing temperature range in which fixing can be performed without causing the occurrence of the offset phenomenon is narrow, and the practicability is still low. In addition, low temperature and low humidity (for example, temperature 10 ° C, RH
Under the environmental conditions of (40%), the temperature of the image support such as transfer paper is low, so that at the time of fixing, the toner tends to be insufficiently melted. Adheres and accumulates and contaminates the roller, thereby causing a conveyance failure such as a paper jam and shortening the service life of the roller.

As described above, it is a fact that some satisfactory capsule toners have not yet been obtained as capsule toners for fixing a heat roller.
This is because it is assumed that the conventional capsule toner is basically applied to the pressure fixing method. That is, the toner is shaped so as to be suitable for a fixing method to which the toner is applied. For example, when a toner designed to be applied to a pressure fixing method is applied to a heat roller fixing method, a problem such as an offset phenomenon occurs. Dots occur, and a sufficient copied image cannot always be formed.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and has as its object to provide a practical fixing temperature range which is excellent in both low-temperature fixability and offset resistance, and has a low temperature and low humidity. Under low environmental conditions, excellent low-temperature fixability is not impaired, fusing can be performed without contaminating the rollers that make up the fixing unit, and blocking resistance, triboelectric charging, and filming resistance are all excellent. And
It is an object of the present invention to provide a heat roller fixing capsule toner capable of stably forming a clear image without fog many times.

[0014]

The capsule toner for fixing with a heat roller according to the present invention comprises fusible core particles and an outer shell made of a thermoplastic resin provided so as to cover the surface of the core particles. In the heat roller fixing capsule toner,
The fusible core material particles contain at least a styrene monomer, a maleic acid monoester and / or a fumaric acid monoester monomer as constituents, and have a glass transition temperature (hereinafter, referred to as T).
g) is 40 to 70 ° C., and the core resin has a peak molecular weight and a weight average molecular weight (hereinafter, referred to as Mw) of 1 × 1.
A colorant having at least two groups of a low molecular weight component (L-form) of 0 ^{3 to} 2 × 10 ^{4 and} a high molecular weight component (H-form) of 1 × 10 ⁵ to 2 × 10 ⁶ in peak molecular weight; As 2
10 to 10 parts by weight of pH 7 or less, BET specific surface area 90 to 2
00m ² / g and DBP oil absorption 50-110 ml / 1
The surface of the encapsulated toner is treated with a silicon-based and / or titanium-based material having a BET specific surface area of 80 to 300 m ² / g, containing 00 g of carbon black and having a pH of 7 or less in a 4% water / methanol solution. It was done.

According to the capsule toner for fixing with a heat roller of the present invention, the core particles contain at least a styrene monomer, a maleic acid monoester monomer and / or a fumaric acid monoester monomer. , A specific Tg
And a specific Mw.

Further, the core particles of the capsule toner for heat roller fixing of the present invention have a structure based on a polyfunctional monomer. Due to this cross-linking structure, even when the Tg of the core material resin is low, the viscoelasticity of the toner at the time of melting becomes an appropriate size, so that the transfer of the toner substance to the heat roller of the heat roller fixing device hardly occurs. Offset resistance is obtained, and this crosslinked structure has a weaker bond than a normal covalent bond. Therefore, even if the crosslinked structure has a Tg similar to that of a resin having a crosslinked structure formed by a covalent bond, it can be fixed at a lower temperature. , And excellent low-temperature fixability is exhibited particularly under low-temperature and low-humidity environmental conditions. As described above, since the toner can be fixed at a low temperature without occurrence of the offset phenomenon, the feasible temperature range is sufficiently widened, and a toner extremely excellent in practical use can be obtained. And, since the core material particles are covered with an outer shell made of a thermoplastic resin, the outer shell provides excellent blocking resistance, good triboelectric charging,
Cleanability and excellent filming resistance are obtained.
Hereinafter, a specific configuration of the present invention will be described.

In the present invention, at least a styrene monomer, a maleic acid monoester and / or a fumaric acid monoester monomer are used as constituents,
A heat roller in which the surface of core particles containing a core resin having a specific Tg and a specific Mw (hereinafter simply referred to as a core resin) is covered with an outer shell made of a thermoplastic resin. This constitutes a fixing capsule toner.

The Tg of the core resin is from 40 to 70 ° C., preferably from 40 to 60 ° C. By using a material having a Tg in such a range, more excellent low-temperature fixability, offset resistance, and durability can be obtained.
That is, when the Tg is too small, the core material particles may be soft and the offset resistance and durability may be reduced. On the other hand, when the Tg is too large, the low-temperature fixability tends to be reduced, and particularly when the Tg is low. Low humidity (eg temperature 10 ° C, RH4
0%), sufficient low-temperature fixability may not be obtained.

In the present invention, Tg is defined as an extension of the base line below Tg and a portion from the rising portion of the peak to the top of the peak when measured at a heating rate of 10 ° C./min using a differential scanning calorimeter. Means the temperature at the intersection with the tangent line showing the maximum slope.

In the present invention, other components may be contained in the core material particles in addition to the above-mentioned core material resin.
It is preferably contained in a proportion of at least% by weight. If this ratio is too small, the offset resistance and durability of the capsule toner may decrease.

The core resin has a molecular weight distribution divided into at least two groups of a low molecular weight component (L-form) and a high molecular weight component (H-form), and is measured by gel permeation chromatography (GPC). The peak molecular weight of each component is 1 × 10 ³ to 2 × 10 ^{3 for} the low molecular weight component (L form).
⁴ and a high molecular weight component (H form) of 1 × 10 ⁵ to 2 × 1
It is intended to be 0 ⁶ within the range of. By using such a resin having a specific molecular weight distribution, it is possible to further improve low-temperature fixability and offset resistance. Further, the specific core material resin can be made tough by the high molecular weight component (H form), so that the outer shell and the core material particles are not destroyed by friction with the carrier or collision with the photoreceptor. As a result, generation of fine powder can be suppressed, and contamination of the photoreceptor surface can be prevented. Therefore, a clear image without fog can be stably formed many times.

On the other hand, when the peak molecular weight of the low molecular weight component (L-form) is smaller than the lower limit in the above-mentioned molecular weight, the blocking resistance of the capsule toner may be reduced. The low-temperature fixability of the toner may decrease. Also,
When the peak molecular weight of the high molecular weight component (H-form) is smaller than the lower limit, the offset resistance and durability of the capsule toner may be reduced. On the other hand, when the Mw is larger than the upper limit, the low-temperature fixability of the capsule toner is reduced. There are cases.

The ratio of the high molecular weight component (H form) is 1
It is preferably from 5 to 75 parts by weight. If the proportion of the high molecular weight component (H-form) is too small, the offset resistance and durability of the capsule toner may be reduced.

The core resin containing such a high molecular weight component (H-form) and a low molecular weight component (L-form) may be added to a styrene monomer, a maleic acid monoester and / or a fumaric acid monoester monomer. The body is preferably introduced at least into the high molecular weight component (H form).

The monomer composition is preferably 30 to 95% by weight, particularly preferably 40 to 95% by weight, of a styrene monomer, and is preferably a maleic acid monoester and / or a fumaric acid monoester monomer. Is 5 to 70% by weight, particularly preferably 5 to 50% by weight. When the content ratio of the maleic acid monoester and / or fumaric acid monoester monomer exceeds 70% by weight, the offset resistance at the time of high-temperature fixing may decrease, and the blocking resistance and the plastic resistance may be reduced. The agent properties may be reduced.

The destruction of the outer shell and core particles caused by friction with the carrier particles or collision with the photoreceptor surface is as follows:
It is mainly caused by a relatively fragile component having a low molecular weight (L-form) in the core material particles. To improve such a low-molecular-weight component (L-form), a polyfunctional monomer and / or Or it is preferred to use a polyfunctional initiator. By using these materials to make the low molecular weight component (L-form) tough, it is possible to suppress the generation of fine powder caused by the destruction of the outer shell and core material particles, which is a cause of the filming phenomenon.

The core resin, which is a mixed resin of the high molecular weight component (H-form) and the low molecular weight component (L-form), has a M
w and the number average molecular weight (hereinafter referred to as Mn) ratio (Mw / M
When the value of n) is from 4 to 40, the offset resistance and the mechanical durability of the capsule toner are further improved. The values of Mw and Mn can be determined by various methods, and there are some differences due to differences in measurement methods, but in the present invention, the values are determined by the following measurement methods.

That is, by gel permeation chromatography (GPC), Mw,
Mn is measured. At a temperature of 35 ° C., a solvent (tetrahydrofuran) was allowed to flow at a flow rate of 1.2 ml / min to obtain a concentration of 0.1 ml.
3 mg of a 25% tetrahydrofuran sample solution as a sample weight is injected and measured. In measuring the molecular weight of a sample, a measurement condition in which the logarithm and the count number of the molecular weight of the calibration curve prepared by using several kinds of monodisperse polystyrene standard samples are included within a linear range is selected. .

The reliability of the measurement results was determined by measuring the NBS706 polystyrene standard sample (Mw
= 28.8 × 10 ⁴ , Mn = 13.7 × 10 ⁴ , Mw /
Mn = 2.11) and the value of the ratio Mw / Mn is 2.11 ± 0.
Confirm by reaching 10. As the GPC column to be used, any column may be adopted as long as the above conditions are satisfied.

As the monomer for obtaining the high molecular weight component (H-form) and the low molecular weight component (L-form) of the present invention, aromatic vinyl monomers such as styrene, α-methylstyrene, halogenated styrene , Vinyltoluene, 4-sulfonamidostyrene, 4-styrenesulfonic acid, etc., and particularly preferably a styrene monomer.
Further, it is an acrylate monomer and a methacrylic acid monomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
N-butyl (meth) acrylate, isobutyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate Phenyl (meth) acrylate, benzyl (meth) acrylate, furfuryl (meth) acrylate, hydroxylethyl (meth) acrylate, hydroxybutyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, (meth) ) Dimethylaminoethyl acrylate, 2-ethylhexyl (meth) acrylate, 2-chloroethyl (meth) acrylate, and the like, preferably an n-butyl acrylate monomer,
It is an n-butyl methacrylate monomer.

Acrylamidoalkylsulfonic acid and / or methacrylamidoacrylsulfonic acid, specifically acrylamidomethylsulfonic acid, acrylamidoethylsulfonic acid, acrylamido n-propylsulfonic acid, acrylamidoisopropylsulfonic acid, acrylamidon-butylsulfonic acid , Acrylamide s-butylsulfonic acid, acrylamide t-butylsulfonic acid, acrylamidepentanesulfonic acid, acrylamidehexanesulfonic acid, acrylamideheptanesulfonic acid, acrylamideoctanesulfonic acid, methacrylamidemethylsulfonic acid, methacrylamideethylsulfonic acid, methacrylamiden -Propyl sulfonic acid, methacrylamide isopropyl sulfonic acid, methacrylamide Illustrate n-butylsulfonic acid, methacrylamide s-butylsulfonic acid, methacrylamide t-butylsulfonic acid, methacrylamidepentanesulfonic acid, methacrylamidehexanesulfonic acid, methacrylamideheptanesulfonic acid, and methacrylamideoctanesulfonic acid. However, the present invention is not limited to this.

Itaconic esters, for example, dimethyl itaconate, dipropyl itaconate, dibutyl itaconate, dioctyl itaconate, diamyl itaconate; maleic esters and fumaric esters, for example, straight-chain or 1 to 8 carbon atoms; Maleic esters and fumaric esters having a branched alkyl group, diethyl maleate, dipropyl maleate, dibutyl maleate, dipentyl maleate, dihexyl maleate, heptyl maleate, octyl maleate, ethyl butyl maleate, ethyl octyl maleate, Butyl octyl maleate, butyl hexyl maleate, pentyl octyl maleate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, dipentyl fumarate, dihexyl fumarate Le, fumaric acid heptyl, fumaric acid octyl, fumaric acid ethylbutyl, fumaric acid ethyl octyl, fumaric acid butyl octyl, fumaric acid butyl hexyl, fumaric acid pentyl octyl;
Unsaturated carboxylic acids and unsaturated dicarboxylic acids, such as (meth) acrylic acid, cinnamic acid, maleic acid, fumaric acid, and itaconic acid; and others such as 2-vinylnaphthalene, itaconic anhydride, and maleic anhydride. It is not limited to this.

Further, as the structural unit of the binder resin polymer (H) of the present invention, a polyfunctional monomer and / or a polyfunctional initiator may be used in order to improve the high-temperature offset property. Preferred examples thereof include styrene monomers such as divinylbenzene, and acrylic polyfunctional monomers such as 1,3-butylene glycol diacrylate, 1,5-pentanediol diacrylate, and neopentyl glycol. Dialact, 1,6-
Hexanediol diolate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, polypropylene diacrylate, N, N'-methylene As methacrylic polyfunctional monomers such as bisacrylamide, pentaerythritol triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, and 1,4-butanediol diacrylate, for example, diethylene glycol dimethacrylate, 1, 3-butylene glycol dimethacrylate, 1,5-pentanediol dimethacrylate , Neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol #
400 dimethacrylate, polyethylene glycol #
600 dimethacrylate, polypropylene dimethacrylate, N, N'-methylenebismethacrylamide, pentaerythritol trimethacrylate, trimethylolpropane trimethacrylate, tetramethylolpropane trimethacrylate, 1,4-butanediol dimethacrylate , 2,2-bis (4-methacryloxypolyethoxyphenyl) propane, aluminum methacrylate, calcium methacrylate, zinc methacrylate, magnesium methacrylate and the like.

Examples of peroxides include t-butyl peroxymethacrylate, t-butylperoxycrotonate, di (t-butylperoxy) fumarate, t-butylperoxycrotonate, and t-butylperoxycrotonate.
Butyl peroxyallyl carbonate, per-trimellitic acid tri-t-butyl ester, pertrimellitic acid tri-
t-amino ester, per-trimellitic acid tri-t-hexyl ester, pertrimellitic acid tri-t-1,1,1,
3,3-tetramethylbutyl ester, pertrimellitic acid tri-t-cumyl ester, pertrimellitic acid tri-
t- (p-isopropyl) cumyl ester, per-trimesic acid tri-t-butyl ester, pertrimesic acid tri-
t-amino ester, per-trimesic acid tri-t-hexyl ester, pertrimesic acid tri-t-1,1,3,3
-Tetramethylbutyl ester, tritrimesic acid-
t-cumyl ester, pertrimesic acid tri-t- (p-
Isopropyl) cumyl ester, 2,2-bis (4,4
-Di-t-butylperoxycyclohexyl) propane, 2,2-bis (4,4-di-t-hexylperoxycyclohexyl) propane, 2,2-bis (4,4-
Di-t-amylperoxycyclohexyl) propane,
2,2-bis (4,4-di-t-octylperoxycyclohexyl) propane, 2,2-bis (4,4-di-
α-cumylperoxycyclohexyl) propane, 2,
2-bis (4,4-di-t-butylperoxycyclohexyl) butane, 2,2-bis (4,4-di-t-octylperoxycyclohexyl) butane.

Others: diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, diallyl chlorendate, ethylene glycol diglycol diglycidyl ether and the like can be exemplified, and at least one of these is used.

In the present invention, as the specific core resin, a resin having at least two maximum values in a molecular weight distribution curve as described above can be preferably used, and a method for obtaining such a resin is as follows. There is no particular limitation. For example, the first-stage polymerization for obtaining either the high-molecular-weight component (H-form) or the low-molecular-weight component (L-form) is performed, and one component obtained by the polymerization is converted to another component. By dissolving in the monomer composition and performing the second stage polymerization, thereby producing the other component, a polymer having at least two maximum values in the molecular weight distribution curve can be obtained as a result. . The polymer obtained by the two-stage polymerization as described above has a low molecular weight component (L
) And the high molecular weight component (H form) are presumed to be uniformly mixed at the molecular level.

This two-stage polymerization can be carried out by, for example, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc., but the solution polymerization method is particularly preferred. Further, the polymer having at least two maximum values in the molecular weight distribution curve can also be obtained by mixing a low molecular weight polymer component (L-form) and a high molecular weight polymer component (H-form). However, the polymer obtained by mixing may not be uniformly mixed at the molecular level, and thus it is preferable to use the two-stage polymerization.

In the present invention, monomer units such as vinyl acetate, vinyl propionate, vinyl chloride, and ethylene may be contained in the molecular chain of the specific core resin within a range not to impair the properties. . Further, a polymer or copolymer of these monomers may be mixed in the core material particles. Further, other resin may be mixed in the core material particles as needed. Such other resins, for example, styrene-acrylic resin, polyurethane resin, styrene-butadiene-based resin, polyester resin,
Epoxy resins and the like can be mentioned.

In the present invention, the surface of the core particles is coated with an outer shell made of a thermoplastic resin. As such a thermoplastic resin, those conventionally used as a resin for toner may be used. Can be. Specifically, for example, a vinyl polymer, a polyester resin, an epoxy resin, a polyurethane resin and the like can be mentioned.
Among them, a vinyl polymer and a polyester resin are particularly preferable, and specifically, for example, styrene-n-butyl acrylate copolymer, styrene-methyl methacrylate-
Examples thereof include an n-butyl methacrylate copolymer and a terephthalic acid-bisphenol A propylene oxide condensate.

The thermoplastic resin forming the outer shell has a Tg
Is preferably 50 ° C. or higher. If the Tg is too small, the blocking resistance of the capsule toner may decrease. The thermoplastic resin forming the outer shell preferably has a ratio of Mw to Mn (Mw / Mn) of 7.0 or more. If the value of the ratio (Mw / Mn) is too small, the offset resistance of the encapsulated toner may decrease. To color the toner of the present invention,
Compounding carbon black (hereinafter referred to as CB)
The chemical and physical properties of the CB used have a great influence on the charging stability of the toner, especially on the transfer efficiency.

That is, in the present invention, when the pH is 7 or less, the BE
CB having a T specific surface area of 90 to 200 m ² / g and a DBP oil absorption (oil absorption using dibutyl phthalate as a medium) of 50 to 110 ml / 100 g or more,
By containing 2 to 10 parts by weight, particularly 5 to 10 parts by weight per 00 parts by weight, uniform chargeability can be obtained,
It is possible to stabilize the charging of the toner, thereby improving the transfer efficiency of the toner.

As the CB, any one that satisfies the above conditions can be used. In particular, furnace black can be advantageously used. Those having a pH of 7 or less have an acidic group (for example, a carboxyl group) on the CB particle surface.
CB can be obtained by subjecting CB to a chemical treatment such as an acid treatment, or by an acid impregnation treatment. Examples of the acid used in these treatments include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as acetic acid, citric acid, propionic acid, benzoic acid, salicylic acid, and toluenesulfonic acid. The amount of the acid is such a small amount as to make the pH 7 or less,
It does not adversely affect the electrical properties of the toner.

If the CB has a pH (pH when carbon black is dispersed in water) of greater than 7, the transfer efficiency of the toner is undesirably low. CB having a pH of 7 or less has excellent dispersibility in the core resin of the present invention.

The CB used in the present invention has a BET specific surface area of 90 to 200 m ² / g and a DBP oil absorption of 50 to 11
Although it is 0 ml / 100 g, the transfer efficiency can be increased as compared with those having a BET specific surface area larger than the above range or those having a DBP oil absorption smaller than the above range.

The effect of CB physical properties on the chargeability of the toner is complicated, and it is certain that the surface condition of the CB particles and the structure of the CB particles have an important effect on the chargeability of the toner particles. The toner of the present invention generally has 5 to 20 particles.
μm, but the surface of the toner particles has
It is desirable that 0.01 to 1.00 wt% of a silicon-based and / or titanium-based material having a BET specific surface area of 80 to 300 m ² / g with a pH of 7 or less in a 4% water / methanol solution is externally added. .

As the surface treating agent, any one satisfying the above conditions can be used, but hydrophobic silica can be particularly advantageously used. Further, fine particles of silica surface-treated with a silane coupling agent, a titanium coupling agent, silicone oil, silicone oil having an amine in a side chain, or the like may be used.

Specific examples of the surface treatment agent include AEROS
IL 130,200,200V, 200CF, 200
FAD, 300, 300CF, 380, R972, R9
72V, R972CF, R974, R976, RX20
0, R200, R202, R805, R812, R81
2S, TT600, MOX80, MOX170, COK
84, titanium oxide T805, titanium oxide P25 (above,
Manufactured by Nippon Aerosil and Tegusa), CAB-O-
SIL L90, LM130, LM150, M5, PT
G, MS55, H5, HS5, LM150D, M7D,
MS75D, TS720, TS610, TS530 (all manufactured by CABOT) and the like can be exemplified.
It is not limited to this.

If necessary, so-called toner components such as a charge control agent (CCA) and a release material may be added to the capsule toner of the present invention. These toner components may be contained in the core material particles, or may be contained in the outer shell. Also, the capsule toner includes
Additives such as a fluidity improver, an abrasive, and a cleanability improver may be contained in a state of being attached to the outer shell or being driven and held in the outer shell.

Examples of the charge control agent (CCA) include metal complex dyes, nigrosine dyes, and ammonium compounds. Various waxes, low molecular weight olefin-based resins, and the like are used as the release agent for heat fixing. The low molecular weight polyolefin wax may be either an unmodified polyolefin wax or a modified polyolefin wax in which a modified component is blocked or grafted to an olefin component. Further, the amount of addition is desirably 5 to 20% by weight based on the total amount of the electrophotographic toner.

Specific examples of the polyolefin wax include “Viscol 660P” and “Viscol 550P”.
(Manufactured by Sanyo Chemical), "Polyethylene 6A" (manufactured by Allied Chemical), "High Wax 400P", "High Wax 100P", "High Wax 105P", "High Wax 320P", "High Wax 550P" (above, Mitsui Petrochemical Co., Ltd.), “Hoechst Wax PE52
0, "Hoechstwax PE130", "Hoechstwax PE190" (both manufactured by Hoechst Japan) and the like, as well as polyethylene wax, block copolymer or graft copolymerized with methyl methacrylate, styrene And the like. Examples thereof include polyethylene wax which has been subjected to block copolymerization or graft copolymerization. As the olefin-based resin, polypropylene, polyethylene, and a propylene-ethylene copolymer are used, and polypropylene is particularly preferable.

As the fluidity improver and the abrasive, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably from 5 μm to 2 μm, and particularly preferably from 5 μm to 500 μm. The specific surface area by the BET method is 20 to 500 m ² / g.
It is preferred that The proportion of the inorganic fine particles used is
It is preferably 0.01 to 5% by weight of the capsule toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, silica lime, diatomaceous earth, and chromium oxide. , Cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like. Particularly, fine powder of silica is preferable.

Examples of the cleaning improver include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, and polymer fine particles such as methyl methacrylate fine particles and styrene fine particles. When a magnetic toner is used, one or both of the core material particles and the outer shell may contain magnetic fine particles.

As a magnetic material, conventionally used for magnetic toner
Magnetic powder, for example, triiron tetroxide (Fe
_ThreeO_Four), Iron sesquioxide (γ-Fe_TwoO_Three), Zinc iron oxide
(ZnFe_TwoO_Four), Yttrium iron oxide (Y_ThreeFe_Five
O₁₂), Cadmium iron oxide (CdFe _TwoO_Four),iron oxide
Gadolinium (Gd_ThreeFe_FiveO₁₂), Copper iron oxide (CuFe
_TwoO_Four), Lead iron oxide (PbFe₁₂O₁₉), Iron oxide nickel
(NiFe_TwoO_Four), Neodymium iron oxide (NdFeO)
_Three), Barium iron oxide (BaFe)₁₂O₁₉), Iron oxide mug
Nesium (MgFe_TwoO_Four), Iron manganese oxide (MnF)
e_TwoO_Four), Iron oxide lanthanum (LaFeO)_Three), Iron powder
(Fe), cobalt powder (Co), nickel powder (Ni)
Which can be used.

A particularly preferred magnetic powder is particulate iron tetroxide (magnetite). Preferred magnetites are octahedral and have a particle size of 0.05 to 1.0 μm.
The magnetite particles may be surface-treated with a silane coupling agent, a titanium coupling agent, or the like.

The magnetic substance is preferably contained in the form of fine powder having an average particle diameter of 0.1 to 1 μm, which is uniformly dispersed. The content ratio of the magnetic substance is 10% of the capsule toner.
The amount is preferably from 10 to 70 parts by weight, particularly preferably from 20 to 50 parts by weight, based on 0 parts by weight.

In the present invention, core particles can be produced, for example, by the following method. (1) The above-mentioned core resin for constituting the core particles and the toner component used as required are melted and kneaded by, for example, an extruder, cooled, finely pulverized by a jet mill or the like, and classified. To obtain core material particles having a desired particle size. (2) The core resin for forming the core particles and the toner component used as necessary are melt-kneaded by, for example, an extruder, and sprayed in a molten state by a spray drier or the like. To obtain core material particles having a desired particle size.

(3) The above-mentioned core resin for forming the core particles and the toner component used as necessary are melt-kneaded by, for example, an extruder, and dispersed in a liquid in a molten state. And obtaining core material particles having a desired particle size.

In the present invention, as a method for providing an outer shell on the surface of the core material particles, a coating solution obtained by dissolving a thermoplastic resin for forming the outer shell in a solvent is used, for example, by a dipping method or a spray drying method. It is possible to use a method of applying a fluidized bed method or the like to the surface of the core material particles, heating and drying to evaporate and remove the solvent, and curing the applied layer during or after drying to form a coating layer. it can. For example, when the coating layer is formed by a fluidized bed method, in a fluidized bed apparatus, the core material particles are raised to an equilibrium height by a rising pressurized gas flow, and then the core material particles fall again. By this time, the coating solution is spray-coated, and this spray-coating is repeated to form an outer shell.

The capsule toner of the present invention may be a two-component developer in combination with a carrier, or may be a one-component developer consisting only of the magnetic capsule toner as a magnetic capsule toner containing a magnetic substance. It may constitute an agent. The capsule toner of the present invention is a capsule toner for fixing with a heat roller, and is used for forming an image as follows, for example. That is, in the electrophotographic method, an electrostatic latent image formed on a photoreceptor serving as a latent image carrier is developed with a two-component developer or a one-component developer configured using the capsule toner of the present invention, The obtained toner image is, for example, electrostatically transferred to a support made of paper or the like, and then the transferred toner is fixed by a heat roller fixing method, thereby forming a fixed image.

The heat roller fixing device used in the heat roller fixing method generally includes a heat roller, a pressure roller arranged in contact with the heat roller, and a heating source. Further, a cleaning roller is disposed in contact with the heat roller as needed. While the temperature of the heat roller is maintained within a certain range by the heating source, the toner is directly contacted with the heat roller by passing the support between the heat roller and the pressure roller onto which the toner has been transferred. Is heat-fixed to a support. The material of the surface of the heat roller is preferably a fluorine-based material or a silicone-based material, and the durability of the heat roller fixing device can be remarkably improved by a synergistic effect with the capsule toner of the present invention.

[0061]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. Hereinafter, “parts” means parts by weight unless otherwise specified.

<Production of Resin A> (for the present invention) 500 ml of toluene was put into a separable flask having a capacity of 3000 ml equipped with a thermometer, a stirrer, a nitrogen gas introducing tube and a falling condenser, and nitrogen gas was introduced through the nitrogen gas introducing tube. Was introduced to make the inside of the flask an inert atmosphere, and then heated with an oil bath to reach the reflux temperature of toluene. Then, 200 g of styrene, mono-n-butyl maleate 8
0 g, 20 g of methacrylic acid, 0.9 g of benzoyl peroxide, a composition of a high molecular weight component (H form) was placed in a flask, and the mixture was reacted at a reflux temperature for 14 hours to obtain a high molecular weight polymer (polymer ( H)) was formed.

Next, a low molecular weight component (L-form) comprising 382 g of styrene, 35 g of α-methylstyrene, 210 g of n-butyl acrylate and 42 g of benzoyl peroxide was placed in a flask containing the solution of the polymer (H).
The polymerization reaction was carried out while slowly dropping the composition. After the dropping of the composition of the low-molecular-weight component (L-form) was completed, a polymerization reaction was further performed for 4 hours to obtain a low-molecular-weight polymer (polymer (L)).

After completion of the reaction, the solvent toluene was distilled off under reduced pressure to obtain a low molecular weight component (L-form) resin. This is referred to as “resin A”. This resin A was obtained by gel permeation chromatography (HLC-802 UR, G
(MH6 column, manufactured by Tosoh Corporation) have maximum values at 7.5 × 10 ³ and 2.8 × 10 ⁵ , respectively, with Mw of 1.2 × 10 ⁵ and Mw / Mn of 17. 1. Tg is 46 ° C.

Physical properties of carbon black

[0066]

[Table 1]

Physical Properties of Surface Treatment Agent

[0068]

Table 2 {NO. Specific surface area (m ² / g) pH} {S (P) 110 5.2 S (Q) 130 4.5 S (R) 230 4.2} ──────────

Example 1 (1) Production of core material particles 100 parts of the resin A and CB (B) 7 as a colorant
And 5 parts by weight of polypropylene "HIWAX 105P" (manufactured by Mitsui Petrochemical Co., Ltd.) in a V-type blender, followed by melt-kneading with a twin-screw kneader, cooling and crushing with a hammer mill. After finely pulverizing with a jet mill, the powder was classified with an air classifier to obtain core material particles having a particle size of 1 to 30 μm. This is referred to as “core particle 1”.

(2) Production of outer shell Styrene-methyl methacrylate-acrylic acid-n-butyl acrylate copolymer (copolymer weight ratio = 65: 1)
5: 5: 15) emulsified dispersion (solid content: 10% by weight) 5
After adding 300 parts by weight of the core particles 1 to 00 parts by weight and sufficiently dispersing, spray drying is performed at an inlet temperature of 180 ° C. and an outlet temperature of 60 ° C., and the surface of the core particles is coated with the copolymer. An outer shell was formed to obtain a capsule toner powder. To 100 parts of the capsule toner powder, 0.3 part of the surface treating agent S (Q) was added and mixed to obtain an encapsulated toner according to the present invention. This is referred to as “toner 1”.

Example 2 2.0 parts of magnetite as a magnetic powder and CB as a coloring agent
(B) A core resin 2 was obtained in the same manner as in Example 1 using 7.0 parts. And S (Q) as a surface treatment agent
Was added to 100 parts by weight of toner particles to obtain toner 2.

Example 3 A toner 3 of the present invention was obtained in the same manner as in Example 1 except that the content of carbon black was changed to 4 parts by weight. Example 4 Toner 4 of the present invention was obtained in the same manner as in Example 1 except that the content of carbon black was changed to 15 parts by weight. Example 5 A toner 5 of the present invention was obtained in the same manner as in Example 1 except that CB (E) was used as a coloring agent.

Example 6 A toner 6 of the present invention was obtained in the same manner as in Example 1 except that CB (A) was used as a coloring agent. Example 7 A toner 7 of the present invention was obtained in the same manner as in Example 1 except that S (R) was used as a surface treatment agent. Example 8 A toner 8 was obtained in the same manner as in Example 1 except that a monooctyl fumarate monomer was used in place of mono-n-butyl maleate in the production of core material particles. Example 9 The same method as in Example 1 except that the method for producing resin A was partially changed to use resin A9 in which the Mw of polymer (H) was 5.5 × 10 ^5. As a result, a toner 8 was obtained. Example 10 The same method as in Example 1 except that the method for producing resin A was partially changed to use resin A10 in which the Mw of polymer (L) was 1.5 × 10 ^4. As a result, a toner 10 was obtained.

Comparative Example 1 At the stage of the production of resin A, mono-n-butyl maleate
Mw and Tg equivalent to that of resin A without using a monomer
Example 1 except that resin A ratio 1 was obtained and used.
A toner ratio of 1 was obtained in the same manner as described above. Comparative Example 2 pH 8.0, DBP oil absorption 45 ml / 100 g, B
ET specific surface area 127m ^Two/ G of carbon black
A toner ratio of 2 was obtained in the same manner as in Example 1 except for using the toner. Comparative Example 3 pH 2.5, DBP oil absorption 100 ml / 100 g,
BET specific surface area 560m^Two/ G carbon black
A toner ratio of 3 was obtained in the same manner as in Example 1 except that
Was.

Comparative Example 4 pH 4.0, DBP oil absorption 42 ml / 100 g, B
A toner ratio of 4 was obtained in the same manner as in Example 1, except that carbon black having an ET specific surface area of 65 m ² / g was used. Comparative Example 5 pH 7.0, DBP oil absorption 115 ml / 100 g,
A toner ratio of 5 was obtained in the same manner as in Example 1 except that carbon black having a BET specific surface area of 220 m ² / g was used. Comparative Example 6 Only core material particles 1 obtained in the same manner as in Example 1 were used as toner (toner ratio 6).

The toner obtained as described above was evaluated by the following method. (3) Preparation of Developer A resin-coated carrier obtained by coating the surface of copper-zinc ferrite particles with styrene-methyl methacrylate copolymer (copolymerization weight ratio = 70:30) on 150 parts by weight of the toner described above. Was mixed to prepare a developer. (4) Photographing test An electrostatic latent image is formed and developed by a copying machine modified from a commercially available electrophotographic copying machine using the above-mentioned developer, and the obtained toner image is transferred onto transfer paper and then fixed with a heat roller. Each of the following items was evaluated without performing an actual photographing test in which a copy image was formed by fixing with a container.

Minimum fixing temperature (fixability) After forming an unfixed image with the above copying machine, a heat roller having a diameter of 30φ and a surface layer made of Teflon (polytetrafluoroethylene manufactured by DuPont) and a silicone rubber surface layer The heat roller fixing device including a pressure roller formed of “KE-1300RVT” (manufactured by Shin-Etsu Chemical Co., Ltd.)
A toner image of a sample toner transferred to a transfer paper of 4 g / m ² was transferred to a heat roller at a linear velocity of 70 mm / sec and a linear pressure of 0.8
The operation of fixing with a nip width of 4.9 mm / kg / cm is repeated at each temperature by setting the set temperature of the heat roller in steps of 5 ° C. within a range of 100 ° C. to 240 ° C. A minimum wiper rubbing was performed, and a minimum fixing temperature for a fixed image showing sufficient sliding resistance was defined as a minimum fixing temperature. The heat roller fixing device used here does not have a silicone oil supply mechanism.
The environmental conditions are normal temperature and normal pressure (temperature 20 ° C., relative humidity 6
0%) and low temperature and low humidity (temperature 10 ° C., relative humidity 40%).

Offset occurrence temperature (offset property) The measurement of the offset occurrence temperature is similar to the measurement of the above-mentioned minimum fixing temperature.
The toner image is transferred and the fixing process is performed by the above-described heat roller fixing device. Then, a blank transfer sheet is sent to the heat roller fixing device under the same conditions, and whether or not toner stain occurs on the transfer sheet is visually observed. The operation was repeated while the set temperature of the heat roller of the heat roller fixing device was gradually increased, and the lowest set temperature at which toner contamination occurred was taken as the offset occurrence temperature.

Fixable Temperature Range (Fixing Temperature Range) The difference between the offset generation temperature and the minimum fixing temperature measured as described above was defined as the fixable temperature range.

Blocking resistance (agglomeration) The blocking resistance test was conducted at a temperature of 55 ° C. and a relative humidity of 6
It was left for 1 day under 0% environmental conditions, and it was determined whether or not agglutinates were formed in the toner. When no agglomerates were found, it was evaluated as “「 ”. And

The fog was determined by measuring the relative density of a white background portion having a document density of 0.0 with respect to the developed image using a reflection densitometer. The white background reflection density was set to 0.0. The evaluation was performed with a relative concentration of 0.01.
The case where the value was less than 0.01 was evaluated as “○”, the case where the value was 0.01 or more and less than 0.03 was evaluated as “Δ”, and the case where the value was 0.03 or more was evaluated as “x”.

Image Quality An actual shooting test was continuously performed 30,000 times by the above copying machine, and the sharpness of the copied image at the initial stage of image formation and after 30,000 times was examined. The evaluation was evaluated as "O" for good, and "△" for practical but not practical.
Those that were inferior and had problems in practice were marked with "x".

Cleaning Performance A 30,000 times actual shooting test was continuously performed by the above copying machine, and each time the number of times of copying reached 5,000, the surface of the photoreceptor cleaned by the cleaning blade was visually observed. It was determined based on the presence or absence of attached matter. In the evaluation, good samples were evaluated as “○”, those which were not good but were at a practical level were evaluated as “△”, and those which were inferior and had practical problems were evaluated as “x”.

Filming Resistance After the actual copying test was continuously performed 30,000 times by the above copying machine, the surface of the carrier particles, the surface of the photoreceptor, and the cleaning blade were observed with an electron microscope or visually, respectively. It was determined by the presence or absence. The case where no attached matter was recognized was marked with “○”, the case where slight attached matter was found was marked with “△”, and the case where considerable attached matter was found was marked with “×”. Table 3 shows the above results.

[0085]

[Table 3] ─────────────────────────────────── Toner Fixing Off Coagulation Fog Image Quality Creafillability Settingニ ン グ 性 ミ ン グ Toner 1 108 224 ○ ○ ○ ○ ○ Toner 2 110 226 ○ ○ ○ ○ ○ Toner 3 106 226 ○ ○ ○ ○ ○ Toner 4 105 228 ○ ○ ○ ○ ○ Toner 5 109 221 ○ ○ ○ ○ ○ Toner 6 111 220 ○ ○ ○ ○ ○ Toner 7 109 219 ○ ○ ○ ○ ○ Toner 8 103 215 ○ ○ ○ ○ ○ Toner 9 115 236 ○ ○ ○ ○ ○ Toner 10 108 229 ○ ○ ○ ○ ○ ────────────────────ト ナ ー Toner ratio 1 104 11 △ △ △ △ ○ Toner ratio 2 116 224 ○ × × △ × Toner ratio 3 118 226 ○ △ △ △ △ Toner ratio 4 119 226 ○ △ △ × × Toner ratio 5 115 228 ○ × △ △ △ Toner ratio 6 115 221 △ × × × × ────────────────────────────────────

As can be understood from the results in Table 3, the toners 1 and 2 of the present invention both have excellent low-temperature fixability, and particularly have sufficient low-temperature fixability even under low-temperature and low-humidity environmental conditions. And also has excellent offset resistance, and has a wide fixing temperature range of 75 to 80 ° C. Further, the anti-blocking property is good, a clear copied image without fog can be obtained even after 30,000 times of the actual photographing test, and the cleaning property and the filming resistance are also good. Further, even under low-temperature and low-humidity environmental conditions, the image forming process can be smoothly performed without causing any trouble such as paper jam due to little contamination of the heat roller.

On the other hand, in the comparative toner 1,
Since it does not have an outer shell, the low-temperature fixability is sufficient, but the blocking resistance is poor, so that the triboelectric chargeability with the carrier is poor, and the resulting copy image is fogged and unclear. . Further, it has poor cleaning properties and filming resistance, and has low durability. Further, under a low-temperature and low-humidity environment, the heat roller is significantly contaminated, which causes a paper jam, making it difficult to perform the image forming process smoothly. Further, in the comparative toner 2, since the comparative resin a constituting the core material particles is not cross-linked by the polyvalent metal compound, the offset resistance is low and the heat roller is significantly stained. In such cases, troubles such as paper jams are likely to occur. Further, after 30,000 times of the actual shooting test, fogging occurs, the image becomes unclear, and the durability is low.

[0088]

According to the present invention, it is possible to obtain a well-balanced electrophotographic toner having excellent thermal and electrical properties.

Claims (3)

[Claims] 1. A capsule toner for fixing a heat roller, comprising a fusible core material particle and an outer shell made of a thermoplastic resin provided so as to cover the surface of the core material particle, wherein the fusible core material particle is , A styrene monomer, a maleic acid monoester and / or a fumaric acid monoester monomer as at least a component, and a glass transition temperature (Tg) of 40
Is to 70 ° C., the core material resin, weight average molecular weight (Mw) 1 × 10 ³ low molecular weight components of ~2 × 10 ⁴ (L form) and 1 × 0 ⁵ ~2 × 10 in peak molecular weight at the peak molecular weight ⁶ having a molecular weight distribution of at least two groups with the high molecular weight component (H-form), 2 to 10 parts by weight of a coloring agent having a pH of 7 or less,
The capsule toner contains carbon black having an ET specific surface area of 90 to ²⁰⁰ m ² / g and a DBP oil absorption of 50 to 110 ml / 100 g, and has a BET specific surface area of 80 or less when the pH of a 4% water / methanol solution is 7 or less. ~ 300
Capsule toner for fixing with heat roller treated with m ² / g silicon-based and / or titanium-based material. 2. The core resin has a weight average molecular weight (Mw) and a number average molecular weight (Mn) ratio (Mw / Mn) of 4 to 4.
2. The capsule toner for fixing with a heat roller according to claim 1, wherein the value is 0. 3. The encapsulated toner for heat roller fixing according to claim 1, wherein the ratio of the core resin in the fusible core particles is 50% by weight or more.