JP2003084497A - Black toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide black toners which are excellent in blocking resistance, preservable property under a high-temperature environment, low-temperature fixability, high-temperature offset resistance, developing stability, acid environment stability and transferability and make high-fineness and high-grade images obtainable. SOLUTION: The black toners containing at least a binder resin, wax and carbon black are formed by allowing the peak of a loss elastic modulus G" to exist within a temperature range of 50 to 70 deg.C, maintaining T1 within a temperature range from 85 to 105 deg.C and specifying ΔT=T2-T1>=20 deg.C when a temperature at which a storage elastic modules G' indicates 1×10<6> (dN/m<2> ) is defined as T1 and a temperature at which a storage elastic modulus G' exhibits 1×10<5> (dN/m<2> ) is defined as T2, incorporating carbon black at 0.5 to 10 mass% per 100 mass pts. binder resin and specifying the average primary grain size of the carbon black subjected to length measurement by sectional TEM observation of the toners to 14 to 60 nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black toner for developing electrostatic images or a toner jet type black toner. More specifically, the present invention relates to a black toner that can be sufficiently fixed even when oil for preventing high temperature offset is not used or a heating and pressure fixing unit in which the amount of oil used is reduced is used.

[0002]

2. Description of the Related Art Recently, in a full-color copying machine proposed, four photoconductors and a belt-shaped transfer body are used, and electrostatic charge images formed on the respective photoconductors are transferred to cyan toner, magenta toner, yellow toner, and After developing with black toner, the transfer material is conveyed between the photoconductor and the belt transfer member and transferred between the straight paths to form a full-color image, or the electrostatic force or gripper on the transfer member surface facing the photoconductor. The transfer material is wrapped by the mechanical action of
A method of obtaining a full-color image by performing the transfer process four times is generally used.

Toners mounted on these full-color copying machines are required to be sufficiently mixed in each color in a heating and pressure fixing process without improving color reproducibility and impairing transparency of an overhead projector (OHP) image. Is. The full-color image forming toner is preferably a low molecular weight binder resin having a sharp melt property, as compared with a black toner for a general black-and-white copying machine. However, in general, when a sharp melt binder resin is used, when the toner is melted in the heat and pressure fixing step, the self-cohesive force of the binder resin is low, so that a problem with the high temperature offset resistance tends to occur. Therefore, for example, Japanese Patent Publication Sho 5
As proposed in Japanese Patent Publication No. 2-3304, Japanese Patent Publication No. 52-3305, and Japanese Patent Publication No. 57-52574, the black toner for general black-and-white copying machines improves high-temperature offset resistance during fixing. Therefore, a relatively highly crystalline wax represented by polyethylene wax or polypropylene wax is used as a release agent.

Further, a toner having a specific storage elastic modulus for improving the offset resistance has also been proposed.

For example, in JP-A-11-84716 and JP-A-8-54750, 180 ° C. or 17
Toners having a specific storage modulus at 0 ° C have been proposed. However, as a toner for full-color image formation that requires both low-temperature fixing and high-temperature offset resistance, sufficient color mixing characteristics, etc., the viscosity of the toner is too low, and the storage stability under high temperature and high humidity environment is satisfactory. Not something you can do.

Further, Japanese Patent Laid-Open No. 5-249735,
JP-A-7-92737, JP-A-7-234542
JP-A-7-295298, JP-A-8-2
No. 34480, JP-A-8-278662, and JP-A-10-171156 also propose a toner having a specific storage elastic modulus. However,
There is still room for improvement in order to secure ideal fixing characteristics as a toner for forming a full-color image and to fix the toner stably even in long-term durability.

For this reason, in a normal full-color image forming toner, an oil such as silicone oil or fluorine oil is applied to the heat fixing roller to improve the high temperature offset resistance. However, the fixed image thus obtained has extra oil attached to its surface, and has image defects characteristic of oil application, such as application unevenness and glare due to oil. On the other hand, at the time of double-sided fixing, the oil on the surface of the first image which has already been fixed may adhere to the photoconductor to cause a new image defect. Further, it has been pointed out that the oil swells the fixing roller and shortens the life of the fixing roller. Further, in this method, in order to prevent oil streaks on the fixed image,
Since it is necessary to uniformly and quantitatively supply the oil onto the surface of the fixing roller, the size of the fixing device tends to increase.

Therefore, in the heating / pressurizing fixing means in which oil is not used or the amount of oil used is reduced, there are great expectations for the toner which suppresses the occurrence of offset, and there is a strong demand for it together with a toner excellent in low-temperature fixability. Has been done.

On the other hand, when carbon black is used as the colorant, many problems tend to occur as compared with the color toner using the usual organic pigment as the colorant.
For example, carbon black generally has a small primary particle size and a large specific surface area, so that it is difficult to uniformly disperse it in the toner.
Free carbon black is also likely to occur. Therefore, sufficient charging cannot be performed, and problems such as toner scattering and fog are likely to occur. In addition, the released carbon black easily causes problems such as sleeve contamination, carrier spent, and drum filming, and it is said that it is difficult to stabilize long-term durability. Further, since carbon black is generally conductive, the charging property of the toner is hindered, uniform charging cannot be performed, the uniformity in the halftone image area is deteriorated, and the uniform transferability at the time of transfer is deteriorated. There is a problem.

In order to solve these problems, for example, a method using a surface-grafted carbon black as disclosed in Japanese Patent Laid-Open No. 56-116044, and Japanese Laid-Open Patent Publication No.
Although a method of using carbon black surface-treated with an aluminum coupling agent as in Japanese Patent Laid-Open No. 3-210849 has been proposed, these methods require complicated and troublesome steps for surface-treating carbon black, It is essential to raise the manufacturing cost and it is difficult to adopt it industrially.

Regarding the improvement of dispersibility of carbon black, JP-A-64-35457 and JP-A-1-35457
Japanese Patent No. 145664 proposes a method of improving dispersibility by using a specific dispersant, but it is difficult to say that this has been sufficiently solved.

Japanese Unexamined Patent Publication (Kokai) No. 10-186713 proposes a black toner composed of carbon black having a relatively high oil absorption and an azo iron compound having a specific structure.
This is a toner having a high tinting strength and stable chargeability, but it leaves some problems in solid uniformity and durability in a high humidity environment.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide a black toner which solves the above problems.

That is, it is an object of the present invention to provide a black toner in which the occurrence of offset is suppressed even when a heating and pressure fixing unit that does not use oil or uses a small amount of oil is used.

An object of the present invention is to provide a black toner excellent in low temperature fixing property.

An object of the present invention is to provide a black toner excellent in storage stability, heat resistance and blocking resistance.

An object of the present invention is to provide a black toner having a high tinting strength which covers a wide dynamic range from low density to high density.

The object of the present invention is to have sufficient triboelectrification property, to prevent toner fusion to the inside of the developing device, that is, to parts such as sleeves, blades, coating rollers, etc., and also good cleaning property. The present invention provides a black toner that does not film on the body.

An object of the present invention is to provide a black toner which has no fog, excellent highlight reproducibility, excellent solid uniformity, and excellent durability stability.

[0020]

The present invention relates to a black toner containing at least a binder resin, wax and carbon black, wherein the loss modulus G "of the black toner has a peak in a temperature range of 50 to 70 ° C. Temperature at which the storage elastic modulus G ′ shows 1 × 10 ⁶ (dN / m ² ), and the storage elastic modulus G ′ shows 1 × 10 ⁵ (dN / m ² ). When T2 is T2, T1 is 85-105
Within the temperature range of ℃, and ΔT = T2-T1 ≧ 20 ℃
The black toner contains 0.5 to 10 parts by mass of carbon black per 100 parts by mass of the binder resin, and the average primary particle size of carbon black measured by TEM observation of the cross section of the black toner is 14 ~ 60n
m relates to black toner.

As a result of extensive studies, the inventors of the present invention have excellent high-temperature offset resistance even when using no heating oil or a heating and pressurizing fixing means in which the amount of oil used is small, and they are used for a long time in a high temperature environment. In order to achieve both storage stability and low temperature fixability, it has been found that it is effective for the toner to satisfy the above requirements.

In addition, it has been found that when the toner satisfies the above requirements, the dispersibility of carbon black is also improved, the charge is stabilized, and excellent image quality and durability can be provided. In addition, it has been found that when the toner contains a metal compound of a specific aromatic carboxylic acid derivative, the dispersibility of carbon black is further improved and excellent charge stabilization can be achieved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The black toner of the present invention will be described in detail below.

In the black toner of the present invention, it is essential that the peak of the loss elastic modulus G "of the toner exists within the temperature range of 50 to 70 ° C. The peak of the loss elastic modulus G" is the high temperature environment of the toner. It is an important factor for keeping good storage stability, heat resistance and blocking resistance under the conditions.If the peak temperature is too low, the storage stability decreases, and conversely if the peak temperature is too high, the low temperature fixability becomes remarkable. It tends to deteriorate and the color mixing property of the toner also largely decreases. Therefore, in the present invention, the peak of the loss elastic modulus G ″ of the toner is 5
It is essential that it exists within a temperature range of 0 to 70 ° C.,
Preferably, it is desirable that it exists within the temperature range of 52 to 68 ° C.

Further, in the black toner of the present invention, the storage
Storage elastic modulus G ′ is 1 × 10⁶(DN / m ²) Is the temperature
Degree T1 and storage elastic modulus G ′ is 1 × 10^Five(DN / m²)
When the temperature shown is T2, T1 is 85 to 105 ° C.
Within the temperature range of ΔT = T2-T1
When ΔT is ΔT ≧ 20 ° C, excellent offset resistance
Exerts a strong effect.

In order to improve the offset property without impairing the low-temperature fixing property, the present inventors have determined the temperature at which the storage elastic modulus G'shows 1 × 10 ⁶ (dN / m ² ) and As a base, the storage modulus G'decreases by one digit, that is, 1
The behavior of the storage elastic modulus G ′ in the temperature range when showing × 10 ⁵ (dN / m ² ) matches the toner fixing property in an actual machine, and the temperature range between them should be kept wide. It has been found that the offset resistance can be improved by this.

That is, the storage elastic modulus G ′ is 1 × 10 ⁶ (d
When the temperature at which N / m ² ) is indicated is T1, it is essential that T1 be within a temperature range of 85 to 105 ° C.
When T1 is 85 ° C. or lower, the storage stability, heat resistance and blocking resistance in a high temperature environment tend to deteriorate, which is not preferable. Further, when T1 is 85 ° C. or less, the toner particles are likely to coalesce with each other and a large toner aggregate is easily formed, which is not preferable. In recent years, as the output speed of copiers and printers has become faster and the main body has become smaller, the temperature inside the machine tends to rise, and in order to stably obtain high-definition and high-quality images, It is important that the toner has sufficient storage stability, heat resistance and blocking resistance in a high temperature environment. Further, when T1 is 85 ° C. or lower, the fluidity of the toner in a high temperature and high humidity environment is lowered, so that a high-definition image cannot be expected.

On the other hand, when T1 exceeds 105 ° C.,
Although the storage stability, heat resistance, and blocking resistance are sufficient, it is difficult to obtain sufficient fixability at low temperatures, which is not preferable. Further, the absolute value of the gloss at the time of forming a full-color image is lowered, and an image having a feeling of strangeness is likely to be formed when a full-color image is formed together with color toners.
Therefore, in the present invention, T1 is preferably 85 to 105 ° C, and more preferably 87 to 103 ° C.

Further, in the present invention, the storage elastic modulus G '
Is 1 × 10 ⁵ (dN / m ² ), the temperature ΔT = T2−T1 is defined as ΔT ≧ 20.
When the temperature is ° C, excellent offset resistance is exhibited. ΔT
Is a numerical value that can be a measure of the toner self-aggregating force when the toner is melted in the heat and pressure fixing step, and this value is 20 ° C.
If it is smaller, a problem with high temperature offset resistance tends to occur. That is, it is an essential requirement in the present invention that the temperature gradient of the self-aggregating property is gentle when the toner is melted by receiving heat or pressure during the fixing step.

Therefore, in order to achieve both sufficient fixability and high temperature offset resistance, and to obtain an image having a uniform gloss, ΔT ≧ 20 ° C. is desirable, and T ≧ 25 ° C. is preferable. Is desirable.

Further, when ΔT ≧ 20 ° C., the dispersibility of carbon black is remarkably improved. The reason for this is not clear, but when considering the wettability of the carbon black surface and the resin, and ease of fitting, there is no particular problem even if the resin is too soft, but the viscosity of the resin due to self-heating of the resin during the kneading process If it seems to greatly decrease, a large share cannot be applied during kneading, and the dispersibility of carbon black tends to be insufficient. Loss elastic modulus, T1, ΔT
In order to bring the above range into the above range, it can be adjusted by appropriately selecting the binder resin to be used.

The binder resin used in the toner of the present invention is
(A) Polyester resin, (b) Hybrid resin having polyester unit and vinyl-based copolymer unit, (c) Mixture of hybrid resin and vinyl-based copolymer, (d) Polyester resin and vinyl-based copolymer A resin selected from the group consisting of a mixture with a polymer and a mixture of (e) a hybrid resin and a polyester resin is preferable.
Further, the molecular weight distribution of the binder resin component measured by gel permeation chromatography (GPC) preferably has a peak molecular weight (Mp) in the range of 4,000 to 30,000, and further, a peak molecular weight (M
p) is more preferably in the range of 4,500 to 25,000, and Mw / Mn is preferably 5.0 or more.

When the peak molecular weight (Mp) is in the range of less than 4,000, the hot offset resistance of the toner is insufficient. On the other hand, the peak molecular weight (Mp) is 30,0.
If it is in the range of more than 00, it becomes difficult to obtain sufficient low-temperature fixability of the toner, and it becomes difficult to apply it to high-speed fixing. Further, when Mw / Mn is less than 5.0, it becomes difficult to obtain good offset resistance.

When the polyester resin (a) is used as the binder resin, an alcohol component and an acid component such as carboxylic acid, carboxylic acid anhydride or carboxylic acid ester can be used as raw material monomers.

The alcohol component is not particularly limited as long as it is a dihydric or higher alcohol, but as the dihydric alcohol component, for example, as the dihydric alcohol component, polyoxypropylene (2.2) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (3.
3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and other alkylene oxide adducts of bisphenol A, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediene methanol,
Examples include dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A and the like.

Examples of the trihydric or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1, and the like.
2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3.
5-trihydroxymethylbenzene etc. are mentioned.

As the acidic component, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or their anhydrides; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or their anhydrides; carbon number Examples include succinic acid substituted with an alkyl group of 6 to 12 or an anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or an anhydride thereof; and the like.

Among them, particularly, the following general formula (1)
And a carboxylic acid component consisting of a carboxylic acid having a valence of 2 or more or a carboxylic acid thereof or an acid anhydride thereof or a lower alkyl ester thereof (for example, fumaric acid, maleic acid, maleic anhydride, phthalic acid, Polyester resin obtained by polycondensation of terephthalic acid, trimellitic acid, pyromellitic acid, etc.) as an acid component is used as a black toner for full-color image formation.
It is preferable because it has good charging characteristics.

[0039]

[Chemical 1] (In the formula, R represents an ethylene or propylene group, and x, y
Are integers greater than or equal to 1, and the average value of x + y is 2 to 10. When a hybrid resin (b) having a polyester unit and a vinyl-based copolymer unit is used as the binder resin, better wax dispersibility, low-temperature fixability, and offset resistance can be expected to be improved.

“Hybrid resin” used in the present invention
Means a resin in which a vinyl-based copolymer unit and a polyester unit are chemically bonded. The "polyester unit" is a part derived from a polyester resin, and the "vinyl-based copolymer unit" is a part derived from a vinyl-based copolymer.

Specifically, a polyester unit and a vinyl-based copolymer unit obtained by polymerizing a monomer having a carboxylic acid ester group such as (meth) acrylic acid ester are formed by a transesterification reaction, preferably It forms a graft copolymer (or block copolymer) using a vinyl copolymer as a trunk polymer and a polyester as a branch polymer.

In the present invention, it is preferable to use a binder resin in which the vinyl-based copolymer and / or the polyester resin contains a monomer capable of reacting with both resin components to form a hybrid resin. Among the monomers constituting the polyester resin, those capable of reacting with the vinyl-based copolymer include, for example,
Examples thereof include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid and itaconic acid, or anhydrides thereof.
Among the monomers constituting the vinyl-based copolymer, those capable of reacting with the polyester resin include those having a carboxyl group or a hydroxy group among the monomers used in the following vinyl-based copolymer, and acrylic acid or methacrylic acid esters. Is mentioned.

Examples of the vinyl-based monomer for forming the vinyl-based copolymer include the following. Styrene; o-methylstyrene, m-methylstyrene, p
-Methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn -Octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o- Styrene and its derivatives such as nitrostyrene and p-nitrostyrene; ethylene,
Styrene unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinyldene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, vinyl propionate , Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, n-octyl methacrylate,
Dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate,
Α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate,
Acrylic esters such as propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; 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 pyrrole, N-vinyl carbazole, N-vinyl indole, N- Examples thereof include N-vinyl compounds such as vinylpyrrolidone; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

Further, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid and mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenylsuccinic anhydride Unsaturated dibasic acid anhydrides such as: maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl ester Half ester of unsaturated dibasic acid such as half ester, alkenyl succinic acid methyl half ester, fumaric acid methyl half ester and mesaconic acid methyl half ester; unsaturated dibasic acid ester such as dimethyl maleic acid and dimethyl fumaric acid; acrylic acid , Α, β-unsaturated acids such as tacrylic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, the α, β-unsaturated acids and lower fatty acids And alkenyl malonic acid, alkenyl glutaric acid, alkenyl adipic acid, acid anhydrides thereof, vinyl monomers having a carboxyl group such as monoesters thereof, and the like.

2-hydroxyethyl acrylate, 2-
Acrylic acid or methacrylic acid esters such as hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; hydroxy groups such as 4- (1-hydroxy-1-methylbutyl) styrene and 4- (1-hydroxy-1-methylhexyl) styrene The monomer which it has is also mentioned as a vinyl-type monomer.

In the black toner of the present invention, the vinyl-based copolymer and the vinyl-based copolymer unit of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. . Examples of the crosslinking agent used in this case include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, 1,3-butylene glycol diacrylate,
Diacrylate compounds linked by an alkyl chain such as 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6 hexanediol diacrylate and neopentyl glycol diacrylate;
And those obtained by replacing the acrylate of these compounds with methacrylate; diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 4
00 diacrylate, polyethylene glycol # 600
Diacrylate compounds linked by an alkyl chain containing an ether bond such as diacrylate and dipropylene glycol diacrylate; and compounds in which the acrylate of these compounds is replaced by methacrylate; polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,
Examples thereof include diacrylate compounds linked by a chain containing an aromatic group and an ether bond such as 2-bis (4-hydroxyphenyl) propane diacrylate; and compounds obtained by replacing acrylate of these compounds with methacrylate.

Further, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, oligoester acrylates and acrylates of these compounds are replaced by methacrylates; triallyl cyanurate, triallyl. A polyfunctional crosslinking agent such as trimellitate can also be used.

The polymerization initiator used when producing the vinyl copolymer of the present invention is, for example, 2,2′-
Azobisisobutyronitrile, 2,2'-azobis (4
-Methoxy-2,4-dimethylvaleronitrile), 2,
2'-azobis (-2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylbutyronitrile), dimethyl-2,2'-azobisisobutyrate,
1,1'-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2'-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4- Dimethyl-4-methoxyvaleronitrile, 2,2'-azobis (2-methyl-propane), methyl ethyl ketone peroxide,
Acetoneacetone peroxide, ketone peroxides such as cyclohexanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butylhydroperoxide, cumene hydroperoxide,
1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, di-cumyl peroxide, α,
α′-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m- Trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate,
Di-2-ethoxyethyl peroxycarbonate, di-
Methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneo Decanoate, t-butylperoxy 2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, di-t-butylperoxyisophthalate, t-butyl peroxyallyl carbonate,
t-amyl peroxy 2-ethylhexanoate, di-
t-butyl peroxyhexahydroterephthalate,
Examples thereof include di-t-butyl peroxyazelate.

Examples of the production method for preparing the hybrid resin used in the black toner of the present invention include the production methods shown in the following (1) to (5).

(1) After the vinyl copolymer is produced, the polyester resin and the hybrid resin are produced in the presence of the vinyl copolymer. The hybrid resin is produced by reacting a vinyl copolymer (a vinyl monomer can be added if necessary) with a polyester monomer (alcohol, carboxylic acid) and / or a polyester resin. In this case,
Organic solvents can be used.

(2) After producing the polyester resin, the vinyl copolymer and the hybrid resin are produced in the presence of the polyester resin. The hybrid resin is produced by reacting a polyester resin (a polyester monomer can be added if necessary) with a vinyl-based monomer and / or a vinyl-based copolymer.

(3) After producing the vinyl copolymer and the polyester resin, the vinyl resin and / or the polyester monomer (alcohol, carboxylic acid) are added in the presence of these polymers to produce a hybrid resin. Also in this case, an organic solvent can be appropriately used.

(4) After producing the hybrid resin, a vinyl-based monomer and / or a polyester monomer (alcohol, carboxylic acid) is added to carry out addition polymerization and / or polycondensation reaction to obtain a vinyl-based copolymer and polyester. Produce resin. In this case, the hybrid resin may be the one produced by the production method of the above (2) to (4), or the one produced by a known production method as the case requires. Furthermore, an organic solvent can be appropriately used.

(5) A vinyl-based copolymer, a polyester resin and a hybrid resin are produced by mixing a vinyl-based monomer and a polyester monomer (alcohol, carboxylic acid, etc.) and continuously performing addition polymerization and polycondensation reaction. . Furthermore, an organic solvent can be appropriately used.

In the above manufacturing methods (1) to (5),
As the vinyl-based copolymer and / or the polyester resin, polymers having a plurality of different molecular weights and crosslinking degrees can be used.

The binder resin contained in the black toner of the present invention is a mixture (c) of the hybrid resin and the vinyl copolymer and a mixture (d) of the polyester resin and the vinyl copolymer. A mixture (e) of the polyester resin and the hybrid resin, and a mixture of the polyester resin, a vinyl-based copolymer, and the hybrid resin may be used.

The glass transition temperature of the binder resin contained in the black toner of the present invention is preferably 50 to 70 ° C, more preferably 52 to 68 ° C. When the glass transition temperature of the binder resin is less than 50 ° C., the fixing property is excellent, but the offset resistance is lowered, and the contamination on the fixing roller and the winding around the fixing roller are likely to occur, which is not preferable. Further, the gloss of the image after fixing becomes too high, the image quality is deteriorated, and the storage stability of the toner tends to be deteriorated.
On the contrary, when the glass transition temperature of the binder resin is higher than 70 ° C., the fixing property is deteriorated and the set fixing temperature of the copying machine body is unavoidably increased, and the obtained image generally has low gloss and is used for full color. As a result, the color mixing property tends to decrease.

Next, the wax used in the present invention will be described. The black toner of the present invention preferably contains one kind or two or more kinds of waxes.

The black toner of the present invention has a temperature of 30 at the endothermic curve in differential thermal analysis (DSC) from the viewpoint of achieving both low temperature fixing property and blocking resistance.
Have one or more endothermic peaks in the range of ~ 200 ° C,
The peak temperature of the maximum endothermic peak in the endothermic peak is 60 to
It is preferably in the range of 110 ° C. More preferably, the maximum peak of the endothermic curve is in the range of 65 to 100 ° C.

When the peak temperature of the maximum endothermic peak is less than 60 ° C., the blocking resistance of the toner is deteriorated, and conversely, when the peak temperature of the maximum endothermic peak is more than 110 ° C., the fixing property tends to be deteriorated. is there. In order for the black toner of the present invention to have an endothermic peak within the above range, the wax shown below may be used. The wax used in the present invention includes the following. Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax, oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; carnauba wax, Examples thereof include waxes containing a fatty acid ester as a main component such as sazole wax and montanic acid ester wax, and those obtained by partially or entirely deoxidizing fatty acid ester such as deoxidized carnauba wax. Further, saturated straight chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as blancidic acid, eleostearic acid, and valinaric acid;
Saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; Saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide; ethylenebisoleic acid amide,
Unsaturated fatty acid amides such as hexamethylene bisoleic acid amide, N, N'-dioleyl adipamide, N, N'-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, N'-di Aromatic bisamides such as stearyl isophthalic acid amide; Aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally called metallic soap); aliphatic hydrocarbon wax and styrene Waxes grafted with vinyl monomers such as acrylic acid and acrylic acid; partial esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils and fats And so on.

As the wax particularly preferably used in the present invention, an aliphatic hydrocarbon wax can be mentioned. For example, a low molecular weight alkylene polymer obtained by radically polymerizing alkylene under a high pressure or a Ziegler catalyst under a low pressure; an alkylene polymer obtained by thermally decomposing a high molecular weight alkylene polymer; a synthesis gas containing carbon monoxide and hydrogen; A synthetic hydrocarbon wax obtained from the distillation residue of hydrocarbon obtained by the method or obtained by hydrogenating these is preferable. Further, the one in which the hydrocarbon wax is fractionated by the use of press sweating method, solvent method, vacuum distillation or fractional crystallization method is more preferably used. Hydrocarbons as a base are those synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often two or more multi-component catalysts) (for example, the gintol method, the hydrocoal method (fluid catalyst bed Hydrocarbon compound synthesized by the use) A wax method in which a lot of waxy hydrocarbons are obtained (hydrocarbons having up to several hundred carbon atoms obtained by the Arge method (using an identification catalyst bed); alkylene such as ethylene is polymerized by a Ziegler catalyst) The above-mentioned hydrocarbon is preferable because it is a straight-chain hydrocarbon having less branching and longer saturation. The wax is used in an amount of 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.

The wax is usually contained in the binder resin by a method of dissolving the binder resin in a solvent, raising the temperature of the resin solution, and adding and mixing while stirring, or a method of mixing at the time of kneading. The addition method is not particularly limited.

Next, the carbon black used in the present invention will be described.

The carbon black used in the present invention is
Carbon black obtained by a furnace black manufacturing method, a gas black manufacturing method, a thermal black manufacturing method, an acetylene black manufacturing method, a lamp black manufacturing method and the like, and the manufacturing method is not particularly limited.

The carbon black of the present invention has an average primary particle size of 14 to 14 measured by TEM observation of the cross section of the toner.
It is desirable that the thickness is 60 nm, preferably 17 to 55 nm, more preferably 20 to 50 nm.

If the average primary particle size is smaller than 14 nm, as will be described later, it is difficult to disperse the carbon black evenly even by the metal compound of the aromatic carboxylic acid derivative which is preferably used in the black toner of the present invention. The absolute value of the charge amount of is low and tends to cause toner scattering and fog. Further, if the average primary particle size is smaller than 14 nm, the toner has a reddish color and is not suitable as a black toner for forming a full-color image.

On the contrary, when the average primary particle size of carbon black is larger than 60 nm, the coloring power becomes too low even if it is dispersed well, which is not preferable. When a large amount of carbon black having a large average primary particle diameter is added to the black toner for the purpose of increasing the coloring power, the uniformity of charging is deteriorated, and fogging tends to occur in durability in a low temperature and low humidity environment.

The average primary particle diameter of carbon black measured by TEM observation of the cross section of the toner is specifically measured as follows. From the cross-sectional photograph of the toner magnified 40,000 times, carbon black that does not form aggregates is randomly extracted and analyzed, and the measurement is repeated until the sampling number exceeds 300 times to obtain the average particle size. In the present invention, a spherical approximation is performed using an image processing device, and a value defined by the obtained diameter is defined as the average primary particle diameter of carbon black. When measuring the average primary particle diameter of carbon black directly from a TEM photograph, the major axis of carbon black is used as the particle diameter, and the number of samplings is 30
The measurement is repeated until it exceeds 0 times to obtain the average particle size.
As the carbon black, one having an average primary particle size in the toner satisfying the above range is appropriately selected and used.

The carbon black of the present invention has a pH of 6.
5 or more, preferably 7.0 or more, more preferably 7.5.
It is preferably ˜10.5. When the pH is lower than 6.5, the functional groups such as carboxyl group and ketone are increased, the association of polyester is strengthened, and the fixability is easily impaired. On the other hand, if the pH is extremely high, the compatibility between the carbon black and the binder resin is lowered and the carbon black is easily detached from the toner. The carbon black of the present invention has a volatile content of 1.5% or less, preferably 1.2% or less. Carbon black with a volatile content of more than 1.5% means that there are many functional groups on the surface of the carbon black. Using this type of carbon black tends to cause a decrease in the amount of charge under high humidity. As a result, the solid uniformity tends to deteriorate.

The carbon black of the present invention preferably has a DBP oil absorption of 20 to 150 ml / 100 g, more preferably 30 to 140 ml / 100 g. If the oil absorption exceeds 150 ml / 100 g, the resistance of the toner tends to decrease, the charge amount tends to decrease in the durability evaluation under a high temperature and high humidity environment, and problems such as toner scattering and fog are likely to occur. Furthermore, the uniform transfer property in a low-temperature and low-humidity environment deteriorates, and the image tends to be ghostly.
On the other hand, when the oil absorption is less than 20 ml / 100 g, the dispersibility of carbon black in the toner particles is not sufficient and the coloring power is likely to decrease.

The carbon black used in the present invention is
Specific surface area due to nitrogen adsorption is 30 ~ 200m²/ G, preferred
40-150m²/ G, more preferably 45 to 1
20m ²/ G is desirable. Specific surface area is 200
m²/ G is larger, it is difficult to uniformly disperse,
As a result, the absolute value of the toner charge amount becomes lower and the toner
It tends to cause scatter. In addition, the toner is reddish
And is not suitable as a black for full-color image formation.
Become. Conversely, the specific surface area is 30m²When less than / g,
Even if dispersed well, the coloring power becomes too low, which is not preferable.
Yes.

The carbon black used in the present invention is
Toluene extraction is less than 0.1%, preferably 0.05%
The following is good. The methods for measuring the pH, volatile matter, DBP oil absorption, and toluene extraction of carbon black are DIN ISO 787/9 and DIN 5355, respectively.
2. DIN 53601, DIN 53553. The specific surface area of carbon black is measured by the BET method using nitrogen adsorption.

In the black toner of the present invention, carbon black is 0.5 to 10 per 100 parts by mass of the binder resin.
It is preferable to contain the compound by mass. More preferably 1.0
˜8.0 parts by mass, more preferably 1.5 to 7.0 parts by mass. When the content of carbon black in the black toner is less than 0.5 parts by mass, the coloring power of the black toner becomes too low and it is difficult to obtain an image having a high image density. On the other hand, the black toner contains carbon black 10
When it is contained in an amount of more than parts by mass, it becomes difficult to control the charge of the black toner, and it is difficult to obtain long-term charge stabilization.

The black toner of the present invention preferably contains a metal compound of an aromatic carboxylic acid derivative. The metal compound of the aromatic carboxylic acid derivative not only functions as a charge control agent, but also contributes to improving the dispersibility of carbon black.

Although the reason why the metal compound of the aromatic carboxylic acid derivative improves the dispersibility of carbon black is not clear, a partial crosslinking reaction is caused by the interaction between the binder resin and the metal compound of the aromatic carboxylic acid derivative. It is considered that the dispersibility of the carbon black which is difficult to disperse is improved by advancing and increasing the shear in the carbon black during kneading. Furthermore, since the metal compound of the aromatic carboxylic acid derivative surrounds the carbon black and functions like a dispersion stabilizer for carbon black, it is effective in stabilizing the finely dispersed carbon black during kneading, and is a reaggregation inhibitor. It is thought that it is also functioning.

Examples of the aromatic carboxylic acid include three kinds of compounds represented by the following general formulas (2) to (4).

[0077]

[Chemical 2] (Wherein, R ₁ to R ₇ are the same or different groups, a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon _{atoms, -OH, -NH 2, -NH (} CH 3 ), -N
_{(CH 3) 2, -OCH 3} , -O (C 2 H 5), - COOH
Or show a -CONH _2. ) Examples of preferable R ₁ include a hydroxyl group, an amino group and a methoxy group, and among them, a hydroxyl group is preferable. As the aromatic carboxylic acid, especially di-tert
-Dialkyl salicylic acids such as butyl salicylic acid are preferred.

Forming a metal compound of an aromatic carboxylic acid derivative
As a metal to be formed, Mg²⁺, Ca ²⁺, Sr²⁺, P
b²⁺, Fe²⁺, Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺, Al
³⁺, Cr ³⁺, Fe³⁺, Zr⁴⁺Can be given. In the present invention
As a metal compound of an aromatic carboxylic acid derivative,
Aluminum compound of di-tert-butylsalicylic acid
Is preferred.

The metal compound of the aromatic carboxylic acid derivative is
For example, an aromatic carboxylic acid derivative is dissolved in an aqueous sodium hydroxide solution, an aqueous solution in which divalent or higher valent metal atoms are melted is added dropwise to the aqueous sodium hydroxide solution, and the mixture is heated and stirred,
Next, the pH of the aqueous solution is adjusted, cooled to room temperature, and then filtered and washed with water to synthesize a metal compound of an aromatic carboxylic acid derivative. However, the synthesis method is not limited to the above.

The metal compound of the aromatic carboxylic acid derivative is
0.5 to 10 parts by weight, preferably 1 to 9 parts by weight, and more preferably 1.5 to 8 parts by weight per 100 parts by weight of the binder resin is used to adjust the viscoelastic properties and triboelectrification properties of the black toner. It is preferable in that When the amount is less than 0.5 part by mass, not only does it not function as a charge control agent, but also good pigment dispersibility cannot be achieved. On the other hand, when the amount is more than 10 parts by mass, the crosslinking proceeds too much and the fixability as a toner is impaired.

In the black toner of the present invention, a compound other than the above-mentioned metal compound of the aromatic carboxylic acid derivative may be used as a charge control agent in order to further stabilize the chargeability thereof.

The black toner of the present invention can be manufactured as follows. The binder resin and carbon black as a colorant, a wax, and further, if necessary, a charge control agent, other additives and the like are sufficiently mixed by a mixer such as a Henschel mixer, and then a heating roll, a kneader, or an extruder. Using a heat kneader such as this, the resins are mutually compatibilized by melting, kneading, and kneading, and after cooling and solidification, pulverization and strict classification are performed to obtain black toner particles. Then, if necessary, an external additive may be mixed to obtain a black toner.

In the present invention, in order to improve the dispersion state of the carbon black in the black toner particles, the first binder resin and the carbon black are charged into a kneader or a mixer, which is not pressurized or under pressure. In order to obtain a first kneaded material, the first binder resin is melted by heating while being mixed with, and then sufficiently kneaded with a kneader such as a three-roll mill. Then, the mixture obtained by adding the second binder resin to the first kneaded product, and further additives such as a charge control agent and wax, if necessary, is melted and kneaded to obtain a second kneaded product. Second
It is preferable to obtain the toner particles by cooling the kneaded product of (1) and then pulverizing and classifying. Here, the first binder resin and the second binder resin may be the same or different resins.

Examples of the kneader include a heating kneader, a single-screw extruder and a twin-screw extruder, and a heating kneader is particularly preferable.

The black toner of the present invention preferably has a weight average particle diameter of 4 to 10 μm. Further, the black toner of the present invention has a number average particle size of 3.5 to 9.5 μm, 5 to 50% by number of particles having a particle size of 4 μm or less in the number distribution of the black toner, and the volume distribution of the black toner. It is preferable that the amount of particles having a particle size of 12.70 μm or more is 7 vol% or less.

The weight average particle diameter of the black toner is 10 μm.
When the value is larger, it means that there are few fine particles that can contribute to high image quality, and although high image density is easily obtained and toner flowability is excellent, on a fine electrostatic charge image on the photosensitive drum It is difficult to adhere faithfully, and the reproducibility of the highlight part deteriorates, and the resolution also tends to decrease. In addition, the toner excessively rides on the electrostatic image more than necessary, which tends to increase the toner consumption amount.

On the contrary, the weight average particle diameter of the black toner is 4 μm.
When it is smaller than m, the amount of charge per unit mass of the toner becomes high, and the image density is lowered, particularly in low temperature and low humidity. This is not suitable for applications with a high image area ratio such as graphic images.

Further, when the black toner of the present invention is used as a two-component type developer which also uses a carrier and the weight average particle diameter is smaller than 4 μm, the contact charging with a charging member such as a carrier is smoothly carried out. The amount of toner that is difficult and cannot be sufficiently charged increases, and the fog due to scattering to the non-image area becomes noticeable. In order to deal with this, it is conceivable to reduce the diameter of the carrier in order to increase the specific surface area of the carrier. However, with toner having a weight average diameter of less than 4 μm, toner self-aggregation easily occurs, and uniform mixing with the carrier is achieved in a short time. It is difficult, and in continuous toner replenishment durability,
Fog tends to occur.

In the black toner of the present invention, it is preferable that toner particles having a particle size of 4 μm or less account for 5 to 50% by number, preferably 5 to 25% by number of the total number of particles. If the number of toner particles having a particle size of 4 μm or less is less than 5% by number, it means that there are few fine toner particles that are essential components for high image quality. As it is continuously used, the effective toner particle component decreases, the balance of the toner particle size distribution shown in the present invention deteriorates, and the image quality tends to gradually deteriorate.

Further, there are 5 toner particles having a particle diameter of 4 μm or less.
If it exceeds 0% by number, the toner particles are likely to aggregate with each other, and the toner particles often behave as toner particles having an original particle size or more. As a result, a rough image is easily formed,
The resolution is lowered, or the density difference between the edge portion and the inside of the electrostatic charge image becomes large, and the image tends to be a hollow image. Furthermore, 7% by volume of particles having a particle size of 12.70 μm or more
The following is preferable for improving image quality.

In the black toner of the present invention, it is preferable that external additives such as a fluidity improver are added to the toner particles from the viewpoints of image quality improvement and storability in a high temperature environment. As the fluidity improver, inorganic fine powder such as silica, titanium oxide, aluminum oxide is preferable. The inorganic fine powder is preferably hydrophobized with a hydrophobizing agent such as a silane coupling agent, silicone oil or a mixture thereof.

Examples of the hydrophobizing agent include silane coupling agents, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents and the like.

Specifically, for example, a silane coupling agent represented by the following general formula (5) is preferable.

[0094]

RmSiYn (5) (In the formula, R represents an alkoxy group, m represents an integer of 1 to 3, Y represents an alkyl group, a vinyl group, a phenyl group, a methacryl group, an amino group, an epoxy group, A mercapto group or a derivative thereof, and n is an integer of 1 to 3, provided that m + n = 4. Examples of the compound represented by the general formula (5) include vinyltrimethoxysilane and vinyltri. Ethoxysilane, γ
-Methacryloxypropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexa Examples thereof include decyltrimethoxysilane and n-octadecyltrimethoxysilane.

The treatment amount of the hydrophobizing agent is preferably 1 to 60 parts by mass, and more preferably 3 to 50 parts by mass with respect to 100 parts by mass of the inorganic fine powder.

Particularly preferable as the hydrophobizing agent in the present invention is an alkylalkoxysilane coupling agent represented by the following general formula (6).

[0097]

[Chemical 4] (In the formula, n represents an integer of 4 to 12, and m represents an integer of 1 to 3.)

In the above alkylalkoxysilane coupling agent, when n is less than 4, the treatment is easy but the degree of hydrophobicity is low, which is not preferable. When n is greater than 12, the hydrophobicity is sufficient, but the titanium oxide fine particles are often coalesced with each other, so that the fluidity-imparting ability is likely to decrease. When m is larger than 3, the reactivity of the alkylalkoxysilane coupling agent is reduced, and it becomes difficult to favorably make hydrophobic.
It is more preferable that n of the alkylalkoxysilane coupling agent represented by the general formula (6) is 4 to 8 and m is 1 to 2.

The treatment amount of the alkylalkoxysilane coupling agent is preferably 1 to 60 parts by mass, more preferably 3 to 50 parts by mass, based on 100 parts by mass of the inorganic fine powder.

The hydrophobizing treatment may be carried out by using one kind of hydrophobizing agent alone, or by using two or more kinds of hydrophobizing agents.
For example, one type of coupling agent may be used alone for hydrophobic treatment, or two types of coupling agents may be used for hydrophobic treatment at the same time, or after another type of coupling agent is used for hydrophobic treatment, another coupling agent may be used for further hydrophobic treatment. You may perform a conversion process.

The fluidity improver is the black toner particles 10
It is preferable to add 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, relative to 0 parts by mass.

The black toner of the present invention can be applied to a one-component developer and a two-component developer, and the present invention is not particularly limited thereto. However, the black toner of the present invention is a two-component developer. When used for, the carrier used in combination can be, for example, surface-oxidized or non-oxidized iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth metals, and alloys thereof or oxides and ferrites. .

In particular, magnetic ferrite particles of three elements of Mn-Mg-Fe formed by using manganese, magnesium and iron as main components are preferable as the carrier. Also,
The carrier is preferably coated with a resin, and the resin is preferably a silicone resin. In particular, a nitrogen-containing silicone resin or a modified silicone resin produced by reacting a nitrogen-containing silane coupling agent with a silicone resin is used to impart a negative triboelectric charge to the black toner of the present invention, environmental stability, and carrier. It is preferable in terms of suppressing the contamination of the surface of the.

The carrier preferably has an average particle diameter of 15 to 60 μm, more preferably 25 to 50 μm in relation to the weight average particle diameter of the black toner. As a method for preparing the carrier so as to have the above-mentioned average particle size and specific particle size distribution, for example, classification can be performed by using a sieve. In particular, in order to carry out classification with high accuracy, it is preferable to repeat the sieving a plurality of times by using a sieve having an appropriate opening. It is also an effective means to use a mesh whose opening shape is controlled by plating or the like.

When a two-component developer is prepared using the black toner of the present invention and the above carrier, the mixing ratio is 2 to 15% by mass, preferably 4 to 13% by mass as the toner concentration in the developer. It is preferable that the value is usually obtained because good results can be obtained. If the toner concentration is less than 2% by mass, the image density tends to be low, and if it exceeds 15% by mass, fog or in-machine scattering tends to increase.

The black toner of the present invention can be used for forming a full-color image for reproducing a multicolor image. An image forming method using the black toner of the present invention will be described below with reference to FIG. 1, which is a preferred specific example of the image forming apparatus.

The image forming apparatus shown in FIG. 1 includes a lower digital color image printer section (hereinafter referred to as "printer section") I and the digital color image reader section (hereinafter referred to as "printer section") I.
II, which is referred to as a “reader unit”, and for example, the printer unit I forms an image on the recording material P based on the image of the document D read by the reader unit II.

The structure of the printer unit I and the structure of the reader unit II will be described below.

The printer section I has a photosensitive drum 1 as an electrostatic charge image carrier which is driven to rotate in the direction of arrow R1.
Around the photosensitive drum 1, along the direction of rotation,
A primary charging device (charging device) 2, an exposure device 3, a developing device (developing device) 4, a transfer device 5, a cleaning device 6, a pre-exposure lamp 7 and the like are arranged. Below the transfer device 5 (that is, in the lower half of the printer unit I), a feeding / conveying unit 8 for the recording material P is arranged, and above the transfer device 5, a separating means 9 is provided.
And a heating and pressure fixing device 10 and a paper discharge unit 11 are arranged on the downstream side of the separating means 9 (downstream side in the conveying direction of the recording material P).

The photosensitive drum 1 has an aluminum drum-shaped substrate 1a and an OPC (organic optical semiconductor) photosensitive layer 1b covering the surface thereof, and is driven in a predetermined direction in the direction of arrow R1 by a driving means (not shown). It is configured to be rotationally driven at a process speed (peripheral speed).

The primary charger 2 includes a shield 2a having an opening at a portion facing the photosensitive drum 1, and a discharge wire 2b arranged inside the shield 2a in parallel with a generatrix of the photosensitive drum 1.
And a grid 2c arranged in the opening of the shield 2a to regulate the charging potential. A charging bias is applied to the primary charger 2 by a power source (not shown), so that the surface of the photosensitive drum 1 has a predetermined polarity,
It is designed to be uniformly charged to a predetermined potential.

The exposure means 3 includes a laser output section (not shown) that emits a laser beam based on an image signal from a reader section II, which will be described later, and a polygon mirror 3a that reflects the laser beam.
And a lens 3b and a mirror 3c. Exposure means 3
Is configured to irradiate the surface of the photosensitive drum 1 with this laser light to expose the photosensitive drum 1 and remove the electric charge in the exposed portion to form an electrostatic latent image. In this embodiment, the electrostatic latent image formed on the surface of the photosensitive drum 1 is separated into four colors of yellow, cyan, magenta, and black on the basis of the image of the original, and the electrostatic latent image corresponding to each color is separated. The images are formed sequentially.

The developing device 4 includes a developing device 4Y in which yellow toner, cyan toner, magenta toner, and black toner of different colors (developer) are housed in order from the upstream side along the rotation direction of the photosensitive drum 1 (direction of arrow R1). 4C, 4
It is equipped with M and 4Bk. Each developing device 4Y, 4C, 4M,
4Bk has a developing sleeve 4a carrying a developer having a toner for developing the electrostatic charge image formed on the surface of the photosensitive drum 1, and has a predetermined color for developing the electrostatic charge image. The developing device is alternatively arranged at a developing position close to the surface of the photosensitive drum 1 by the eccentric cam 4b. The developer toner carried on the developing sleeve 4a develops the electrostatic charge image to form a toner image (visible image) as a visible image. The developing devices of three colors other than the developing device used for the development are retracted from the developing position.

The transfer device 5 includes a transfer drum (transfer material carrier) 5a for carrying the transfer material P on its surface, a transfer charger (transfer charging means) 5b for transferring the toner image on the photosensitive drum 1 to the transfer material P, It has an attraction charger 5c for attracting the transfer material P to the transfer drum 5a, and an attraction roller 5d, an inner charger 5e, and an outer charger 5f facing the attraction charger 5c, which are rotatably supported in the direction of arrow R5. A transfer material carrying sheet 5g made of a dielectric material is integrally stretched in a cylindrical shape in the opening area of the peripheral surface of the transfer drum 5a. Transfer material carrying sheet 5g
Uses a dielectric sheet such as a polycarbonate film. The transfer device 5 is configured to adsorb and carry the transfer material P on the surface of the transfer drum 5a. The cleaning device 6 includes a cleaning blade 6a that scrapes off the residual toner remaining on the surface of the photosensitive drum 1 without being transferred to the transfer material P, and a cleaning container 6b that collects the scraped toner.

The pre-exposure lamp 7 is disposed adjacent to the upstream side of the primary charging device 2 and removes unnecessary charges on the surface of the photosensitive drum 1 cleaned by the cleaning device 6.

The paper feeding / conveying unit 8 is provided with transfer materials P of different sizes.
A plurality of sheet feeding cassettes 8a for stacking and storing sheets, a sheet feeding roller 8b for feeding the transfer material P in the sheet feeding cassette 8a, a plurality of conveying rollers, a registration roller 8c, etc. P is supplied to the transfer drum 5a.

The separating means 9 has a separating charger 9a for separating the transfer material P after the toner image is transferred from the transfer drum 5a, a separating claw 9b, and a separating push-up roller 9c.

The heat and pressure fixing device 10 has a fixing roller 10a having a heater inside and a pressure roller 10b which is arranged below the fixing roller 10a and presses the transfer material P against the fixing roller 10a.

The paper discharge unit 11 has a transport path switching guide 11a, a discharge roller 11b, a paper discharge tray 11c, and the like, which are arranged on the downstream side of the heat and pressure fixing device 10. Further, below the transport path switching guide 11a, the transport vertical path 11 is used to form images on both sides of one transfer material P.
d, reverse path 11e, stacking member 11f, intermediate tray 11
g, further conveying rollers 11h and 11i, reversing roller 11
j etc. are arranged.

A potential sensor S1 for detecting the charging potential on the surface of the photosensitive drum is provided between the primary charger 2 and the developing device 4 around the photosensitive drum 1, and between the developing device 4 and the transfer drum 5a. A density sensor S2 for detecting the density of the toner image on the photosensitive drum 1 is arranged in each of the above.

Next, the reader section II will be described. The reader unit II arranged above the printer unit I is
A document table glass 12a on which the document D is placed, an exposure lamp 12b for exposing and scanning the image surface of the document D while moving, a document D
A plurality of mirrors 12c for further reflecting the reflected light from
It has a lens 12d that collects reflected light, and a full-color sensor (not shown) that forms a color separation image signal based on the light from the lens 12d. The color-separated image signal is processed by a video processing unit (not shown) via an amplifier circuit (not shown), and is sent to the printer section I described above. Next, the operation of the image forming apparatus having the above configuration will be described. In the following description,
A four-color full-color image is formed in the order of yellow, cyan, magenta, and black.

The image of the document D placed on the platen glass 12a of the reader unit II is irradiated by the exposure lamp 12b and color-separated so that the yellow image is first read by the full color sensor 12e and subjected to predetermined processing. And sent as an image signal to the printer unit I.

In the printer section I, the photosensitive drum 1 is indicated by the arrow R.
It is driven to rotate in one direction, and the surface is uniformly charged by the primary charger 2. Based on the image signal sent from the reader unit II described above, laser light is emitted from the laser output unit of the exposure unit 3, and the surface of the charged photosensitive drum 1 is exposed by the optical image E via the polygon mirror 3a and the like. To do. Electric charges are removed from the exposed portion of the surface of the photosensitive drum 1,
As a result, an electrostatic charge image corresponding to yellow is formed.
In the developing device 4, the yellow developing device 4Y is arranged at a predetermined developing position, and the other developing devices 4C, 4M, 4B.
k is retracted from the developing position. The electrostatic toner image on the photosensitive drum 1 is visualized as a yellow toner image by yellow toner attached by the developing device 4Y. The yellow toner image on the photosensitive drum 1 is transferred to the transfer material P carried on the transfer drum 5a. As the transfer material P, the transfer material P having a size suitable for an original image is supplied to the transfer drum 5a from a predetermined paper feed cassette 8a through a paper feed roller 8b, a conveyance roller, a registration roller 8c and the like at a predetermined timing. It was done. The transfer material P supplied in this manner is attracted so as to wind around the surface of the transfer drum 5a and rotates in the direction of arrow R5, and the yellow toner image on the photosensitive drum 1 is transferred by the transfer charger 5b.

On the other hand, the photosensitive drum 1 after the transfer of the yellow toner image has the residual toner on the surface removed by the cleaning device 6 and the unnecessary charges removed by the pre-exposure lamp 7, and the next charge starting from the primary charging. Used for image formation.

The processes from the reading of the original image by the reader unit II to the transfer of the toner image onto the transfer material P on the transfer drum 5a, the cleaning of the photosensitive drum 1, and the removal of charge are performed in the other colors than yellow. That is, the same process is performed for cyan, magenta, and black, and four color toner images of yellow toner, cyan toner, magenta toner, and black toner are transferred to the transfer material P on the transfer drum 5a so as to overlap each other. .

Transfer material P on which the four color toner images have been transferred
Is separated from the transfer drum 5a by the separation charging device 9a, the separation claw 9b, and the like, and is conveyed to the fixing device 10 with the unfixed toner image carried on the surface. The transfer material P is heated and pressed by the fixing roller 10a and the pressure roller 10b of the heating and pressure fixing device 10, the color toner image is melted and fixed, and a full-color image is formed on one surface of the transfer material. The recording material P after fixing is discharged onto the paper discharge tray 11c by the discharge roller 11b.

Next, referring to FIG. 2, the heating and pressure fixing device 1
0 will be described.

In FIG. 2, the fixing roller 10a which comes into contact with the toner image is, for example, 1 on an aluminum cored bar 31 made of aluminum.
mm-thick HTV (high temperature vulcanization type) silicone rubber layer 32,
With a specific addition type silicone rubber layer 33 on the outside,
It is possible to use one having a diameter of 60 mm.

On the other hand, the pressure roller 10b includes, for example, an HTV having a thickness of 1 mm and a specific addition type silicone rubber layer 3 having a thickness of 1 mm on a core metal 34 made of aluminum.
5 may be provided and the diameter of 60 mm may be used.

The fixing roller 10a is provided with a conveying roller heater 36, which is a heat generating means, inside a core metal 31, and the pressure roller 10b is also provided with a heater 37 inside a core metal 34 so that a recording material is formed. Heating is performed from both sides of P.

The thermistor 38 in contact with the pressure roller 10b detects the temperature of the pressure roller 10b, and the controller 39 controls the halogen heaters 36 and 37 based on the detected temperature to fix the fixing roller 10a and the pressure roller 10a. Both the temperatures of the rollers 10b are controlled so as to be maintained constant at 170 ° C. The fixing roller 10a and the pressure roller 10b have a total pressure of about 80 k by a pressure mechanism (not shown).
Pressurized with g.

In FIG. 2, O is an oil applying device, C is a cleaning device, and C1 is a cleaning blade for removing oil stains on the pressure roller 10b. The oil applicator O uses the dimethyl silicone oil 41 in the oil pan 40 to pump up the oil 5
The oil application amount is regulated by the oil application amount adjusting blade 44 via the oil application rollers 0 and 42 and the oil application roller 43, and the oil is applied to the fixing roller 10a. The cleaning device C cleans the surface of the fixing roller 10a with the web 46 abutted on the fixing roller 10a by the abutting roller 45.

In the above-mentioned fixing device 10, the transfer material P carrying the unfixed toner image on the surface is nipped and conveyed in the fixing nip between the fixing roller 10a and the pressure roller 10b, and at this time, the heating material is heated from both front and back sides. The toner is fixed by being pressed. At this time, the toners attached to the fixing roller 10a and the pressure roller 10b are removed by the cleaning device C and the cleaning blade C1, respectively.

The above description has been made on the case where the full color image is formed only on one surface of the transfer material. Next, referring to FIG. 1, the method and apparatus for forming the full color image on both the front surface and the back surface of the transfer material will be described. While explaining.

When forming a full-color image on both sides of the transfer material P, the fixing device 10 immediately drives the transfer path switching guide 11a to transfer the discharged transfer material P to the transfer path 1
After passing 1d through the reversing path 11e, by reversing the reversing roller 11j, the trailing end when fed is made to be the leading end, and it is withdrawn in the direction opposite to the fed direction and is stored in the intermediate tray 11g. After that, the transfer material P having the full-color image on one surface of the intermediate tray 11g is sent to the transfer drum 5a, and the yellow toner, cyan toner, and magenta toner color toners are transferred to the other surface by the above-described image forming process. Further, the black toner is transferred. The full-color image of the transfer material P is the transfer drum 5.
Since it comes into contact with a, the silicone oil that has adhered to the full-color image surface during fixing adheres to the transfer drum 5a. Silicone oil usually tends to hinder the transfer process, but since the black toner of the present invention is excellent in the absorbability of silicone oil, the amount of silicone oil adhering to the transfer drum 5a is extremely small as compared with the conventional case.

The transfer material P having the unfixed color toner image on the other surface of the transfer material is separated from the transfer drum 5a and sent to the fixing device 10, and the unfixed color toner image is heated and pressed onto the transfer material. It is fixed. In this way, full-color images are formed on both surfaces of the transfer material P. Since the black toner of the present invention has a specific particle size distribution and a specific elastic modulus, both surfaces can be satisfactorily formed by using the black toner of the present invention, and transfer to the fixing roller 10a and the pressure roller 10b is performed. The wrapping of the material P is suppressed, and the occurrence of the offset phenomenon is satisfactorily prevented. In particular, it is preferable to use the black toner to which the hydrophobized aluminum oxide fine powder is externally added.

When the black toner of the present invention is used, contamination of silicone oil or the like on the transfer material carrying sheet 5g of the transfer drum 5a is extremely small as compared with the conventional one, but if necessary, the fur brush 13a and the backup brush 13 are used.
b, the oil removing roller 14a and the backup brush 1
Cleaning may be performed by 4b. Such cleaning is
If necessary, it is performed before or after image formation, and when jamming (paper jam) occurs, it is performed at any time.

Next, methods for measuring each physical property will be described below. (1) Method of Measuring Elastic Modulus of Toner A toner is pressure-molded into a disk-shaped sample having a diameter of 8 mm and a thickness of about 2 to 3 mm. Next, set on the parallel plate and
The temperature is gradually raised in the temperature range of 0 to 200 ° C., and the temperature dispersion is measured. The temperature rising rate is 2 ° C./min, the angular frequency (ω) is fixed at 6.28 rad / sec, and the strain rate is automatic. The temperature is plotted on the horizontal axis and the storage elastic modulus (G ') and loss elastic modulus (G ") are plotted on the vertical axis, and the values at each temperature are read.
For the measurement, RDA-II (manufactured by Rheometrics) can be used, but the device is not limited to this.

(2) Method for measuring endothermic peak of toner ASTM D3418-8 using a differential scanning calorimeter (DSC measuring device), DSC-7 (manufactured by Perkin Elmer Co., Ltd.)
Measure according to 2. A measurement sample is precisely weighed in an amount of 2 to 10 mg, preferably 5 mg.

This was placed in an aluminum pan, and an empty aluminum pan was used as a reference, and the measurement temperature range was 30 to 20.
The measurement is performed at a temperature rising rate of 10 ° C / min between 0 ° C and normal temperature and normal humidity. In this temperature rising process, the endothermic peak of the main peak of the DSC curve in the temperature range of 30 to 200 ° C. is obtained.

(3) GPC measurement of binder resin The molecular weight of the chromatogram by gel permeation chromatography (GPC) is measured under the following conditions.

The column was stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min to adjust the sample concentration to 0.05 to 0.6 mass%. About 50 to 200 μl of the THF sample solution of the binder resin is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value and the number of counts (retention time) of a calibration curve prepared from several kinds of monodisperse polystyrene standard samples. The standard polystyrene sample for preparing the calibration curve is, for example, manufactured by Tosoh Corporation or Pre.
secure Chemical Co. Made with a molecular weight of 6
× 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 1
0 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ ,
It is suitable to use those of 8.6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ , and to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

As the column, a plurality of commercially available polystyrene gel columns are preferably combined in order to accurately measure the molecular weight region of 10 ³ to 2 × 10 ⁶ , for example, shodex GPC KF-801 manufactured by Showa Denko KK 80
2, 803, 804, 805, 806, 807 combinations and Waters μ-styragel 50
A combination of 0, 10 ³ , 10 ⁴ and 10 ⁵ can be mentioned.

(4) Measurement of toner particle size distribution In the present invention, the average particle size and particle size distribution of the toner are measured using a Coulter Counter TA-II type (manufactured by Coulter Co.), but a Coulter Multisizer (manufactured by Coulter Co.) is used. It is also possible to use. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using first grade sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan Co.) can be used. As a measuring method,
A surfactant, preferably 0.1 to 5 ml of alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is about 1 to 3 with an ultrasonic disperser.
Dispersion treatment is carried out for a minute, and 2.00 μm is obtained by using the measuring device with an aperture of 100 μm as an aperture.
The volume distribution and the number distribution of the toner are calculated by measuring the volume and the number of the toner. Then, the weight-based weight average particle diameter (D4) (the median value of each channel is used as a representative value for each channel) determined from the volume distribution according to the present invention is determined. Further, the number-based number average particle diameter is calculated from the weight-based weight average particle diameter (D4).

The channels are 2.00 to 2.52.
μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm
m; 4.00 to 5.04 μm; 5.04 to 6.35 μ
m; 6.35 to 8.00 μm; 8.00 to 10.08 μm
m; 10.08-12.70 μm; 12.70-16.
00 μm; 16.0-20.20 μm; 20.20
25.40 μm; 25.40-32.00 μm; 32.
13 channels of 00-40.30 μm are used.

(5) Method for Measuring Average Primary Particle Size of Carbon Black in Toner In the present invention, the average primary particle size of carbon black in the toner is measured as follows. Specifically, after sufficiently dispersing the toner in an ultraviolet curable acrylic resin, it is irradiated with ultraviolet rays to be cured, and the obtained cured product is surfaced using an ultramicrotome, and then ruthenium tetroxide is used. (RuO ₄ ), or if necessary, osmium tetroxide (OsO ₄ ) is also used together for electron staining, and then a thin sample is cut out using an ultramicrotome equipped with a diamond knife, and a transmission electron microscope ( TE
Observe the cross-sectional layer morphology of the toner using M). From the cross-sectional photograph of the toner obtained in this way (for example, a cross-sectional photograph magnified 40,000 times), it was decided to randomly extract and analyze carbon black that did not form aggregates until the sampling number exceeded 300 times. Repeat the measurement to determine the average particle size.

In the present invention, carbon black is spherically approximated using an image processing apparatus, and the value defined by the obtained diameter is taken as the average primary particle diameter (A) of carbon black. When measuring the average primary particle size of carbon black directly from a TEM photograph, the major axis of carbon black is used as the particle size, and the measurement is repeated until the number of samplings exceeds 300 times to obtain the average primary particle size (B). Ask. In the present invention, almost the same results were obtained in both (A) and (B) above.

[0148]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples. <1> Production of Binder Resin (Hybrid Resin Production Example 1) As a vinyl-based copolymer, styrene 1.9 mol, 2-ethylhexyl acrylate 0.21 mol, fumaric acid 0.15 mol, α-
0.03 mol of a dimer of methylstyrene and 0.05 mol of dicumyl peroxide are placed in a dropping funnel.

In addition, polyoxypropylene (2.2)-
2,2-bis (4-hydroxyphenyl) propane 7.
0 mol, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 3.0 mol,
Terephthalic acid 3.0 mol, trimellitic anhydride 2.0
mol, fumaric acid 5.0 mol and dibutyltin oxide 0.
2 g was placed in a glass 4-liter four-necked flask, and a thermometer, a stir bar, a condenser and a nitrogen introducing tube were attached and placed in a mantle heater. Next, after replacing the inside of the flask with nitrogen gas, the temperature was gradually raised with stirring, and the vinyl copolymer monomer, the cross-linking agent and the polymerization initiator were added from the dropping funnel while stirring at a temperature of 145 ° C. It was added dropwise over 4 hours. Then, the temperature was raised to 200 ° C. and the reaction was carried out for 4 hours to obtain a hybrid resin (1). The results of molecular weight measurement by GPC are shown in Table 1. (Hybrid Resin Production Example 2) 3.8 mol of styrene,
Except that the amount used was changed to 0.07 mol of dimer of α-methylstyrene and 0.1 mol of dicumyl peroxide,
A hybrid resin (2) was obtained by reacting in the same manner as in Hybrid Resin Production Example 1. The results of molecular weight measurement by GPC are shown in Table 1. (Hybrid Resin Production Example 3) 4.0 mol of maleic acid and 3.5 mol of itaconic acid were used instead of 5.0 mol of fumaric acid.
Using l, dicumyl peroxide 0.05m
A hybrid resin (3) was obtained by reacting in the same manner as in Hybrid Resin Production Example 1 except that 0.1 mol of isobutyl peroxide was used instead of ol. The results of molecular weight measurement by GPC are shown in Table 1. (Hybrid resin production example 4) terephthalic acid 3.0mo
1 and 5.2 mol of trimellitic anhydride instead of 2.0 mol of trimellitic anhydride were reacted in the same manner as in Hybrid Resin Production Example 1 to obtain a hybrid resin (4). The results of molecular weight measurement by GPC are shown in Table 1. (Polyester Resin Production Example 1) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl)
Propane 3.6 mol, polyoxyethylene (2.2)
1.6 mol of -2,2-bis (4-hydroxyphenyl) propane, 1.7 mol of terephthalic acid, 1.1 mol of trimellitic anhydride, 2.4 mol of fumaric acid and 0.1 g of dibutyltin oxide were added to 4 liters of glass made of 4 liters. The flask was placed in a one-necked flask, a thermometer, a stirring rod, a condenser and a nitrogen introducing tube were attached and placed in a mantle heater. Under a nitrogen atmosphere, the reaction was carried out at 215 ° C. for 5 hours to obtain a polyester resin (5). The results of molecular weight measurement by GPC are shown in Table 1. (Polyester Resin Production Example 2) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl)
Propane 1.6 mol, polyoxyethylene (2.2)
Same as polyester resin production example 1 with the monomer composition of 3.3 mol of 2,2,2-bis (4-hydroxyphenyl) propane, terephthalic acid 1.6 mol, trimellitic anhydride 0.3 mol, and fumaric acid 3.2 mol. Then, a polyester resin (6) was obtained. The results of molecular weight measurement by GPC are shown in Table 1. (Production Example 1 of vinyl-based copolymer) Styrene 2.2mo
1, 2-ethylhexyl acrylate 0.23 mol,
Dicumyl peroxide (0.08 mol) and dibutyltin oxide (3.2 g) were placed in a 3-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser and a nitrogen inlet tube, and nitrogen was placed in a mantle heater. The reaction was performed while stirring at a temperature of 225 ° C. in an atmosphere to obtain a vinyl-based copolymer (7). The results of molecular weight measurement by GPC are shown in Table 1.

[0150]

[Table 1] Table 2 shows the waxes used to manufacture the black toner of this example.

[0151]

[Table 2] Table 3 shows the carbon black used in the production of the black toner of this example.

[0152]

[Table 3]

[0153]

Example 1 Black toner 1 was prepared by the following method. (First kneading step) -Hybrid resin (1) 60 parts by mass-Carbon black (a) 40 parts by mass The above raw materials are first charged into a kneader-type mixer, and the temperature is raised without pressure while mixing. The resin was melted and kneaded for 30 minutes in a state where the resin was sufficiently melted, and after the first step was completed, it was cooled, and the kneaded product was taken out and pulverized to obtain a first kneaded product. (Second kneading step) -First kneaded product 10.0 parts by mass (carbon black content 40% by mass) -Hybrid resin (1) 94.0 parts by mass-Wax (A) 5.0 parts by mass Aluminum compound of di-tertiarybutylsalicylic acid (charge control agent) 4.0 parts by mass Preliminarily mixed with the above-mentioned formulation using a Henschel mixer, and melt-kneaded at a temperature of 120 ° C. with a twin-screw extrusion kneader. After cooling, it was coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized to a particle size of 20 μm or less by an air jet type fine pulverizer. Further, the obtained finely pulverized product was classified and selected so that the weight average particle diameter in the particle size distribution was 7.0 μm to obtain black toner particles (classified product).

Hydrophobic aluminum oxide (BET 180 m ² / g) treated with i-C ₄ H ₉ Si (OCH ₃ ) ₃ : 23 parts by mass for the purpose of improving fluidity and imparting charging characteristics.
To 100 parts by weight of the black toner particles,
Black toner 1 was prepared by combining 1.0 parts by mass. The black toner 1 had a weight average particle diameter of 7.0 μm.

Further, black toner 1 and magnetic ferrite carrier particles surface-coated with a silicone resin (average particle diameter 45 μm) were mixed so as to have a toner concentration of 7% by mass, and two-component black developer 1 was obtained. did. Table 4 shows the toner formulation and measurement results of physical properties.

With this black developer 1, a color copying machine C
Using a modified machine in which the oil application mechanism of the fixing unit of LC-800 (made by Canon) is removed, in a single color mode under low temperature and low humidity environment (15 ° C / 10%), high temperature and high humidity environment (30 ° C)
/ 80%) and an original document with an image area ratio of 20%, a durability test of 10,000 sheets and normal temperature and humidity (23 ° C /
A fixing test (set fixing temperature is 170 ° C.) was conducted at 60%. Further, the evaluation of the fixable area was performed by modifying the fixing unit so that the fixing temperature can be manually set. That is, the unfixed image was fixed while increasing the fixing temperature by 10 ° C. from the low temperature side, and the fixing start temperature and the offset generation temperature were confirmed.

In the durability evaluation under a low temperature and low humidity environment, the image density was stable between 1.5 and 1.7, and a black image that faithfully reproduces the original without fog even after 10,000 sheets of durability was obtained. Was obtained. Conveyance in the copying machine and detection of developer concentration were also good, and stable image density was obtained. Further, even after repeated copying of 10,000 sheets (fixing temperature was 170 ° C.), offset to the fixing roller did not occur at all. The occurrence of offset on the fixing roller was determined by visually observing the surface of the fixing roller after repeated copying.
In the durability evaluation under high temperature and high humidity environment, the image density is 1.6 to
A stable black image was obtained between 1.8 and a black image that faithfully reproduces the original without fog even after 10,000 sheets of durability was obtained. There was no stain inside the machine after running, and almost no toner scattering was confirmed. The offset to the fixing roller was also confirmed by a visual inspection of the offset condition after repeatedly copying 10,000 sheets (visually observing the surface of the fixing roller after copying), which was carried out in a normal temperature and normal humidity environment with the fixing temperature set to 170 ° C. It didn't happen at all. Further, during the durability evaluation of 10,000 sheets, no image defect due to defective fixing was observed. When the fixing temperature range was examined, fixing was possible from 120 ° C. and offset did not occur up to 210 ° C.

As a result of examining the storage stability of the black toner 1, good data were shown. That is, the blocking resistance of the sample toner was evaluated by leaving it in an oven at 50 ° C. for 2 weeks. The evaluation was based on the level of visual agglutination. The results are shown in Table 4. The evaluation criteria of blocking resistance are as follows. A: Aggregates are not seen at all and the fluidity is very good. B: Some aggregates are seen but they are easily disentangled. C: Aggregates are not sufficiently disentangled by the developer stirring device.

Instead of the carbon black used in Black Toner 1, a copper phthalocyanine type cyan pigment (Pig
ment Blue 15: 3), a diaralead-based yellow pigment (Pigment Yellow 17), a quinacridone-based magenta pigment (Pigment 122)
Cyan toner 1, yellow toner 1, and magenta toner 1 are prepared in the same manner, respectively, using
A developer was prepared and imaged in the same manner as in the two-component black developer 1. A bright full-color image with excellent re-line reproduction was obtained.

[0160]

[Examples 2 to 5] Examples 2 to 5 were carried out except that the hybrid resin (1) was replaced by the hybrid resin (2), the hybrid resin (3), the polyester resin (5), and the vinyl copolymer (7). Black toners 2 to 5 were prepared in substantially the same manner as in Example 1. Then, using these black toners, two-component black developers 2 to 5 were obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. Although the fixable width of the black toner 5 was narrower than that of Example 1, it was within a practical level. About the endurance test, almost the same result was obtained. The results are shown in Table 4. However, with the black toner 5, the fog was observed in the latter half of the durability under low temperature and low humidity, although only slightly.

[0162]

Example 6 In Example 1, the aluminum compound of di-tert-butylsalicylic acid (charge control agent) was added to 6.
Black toner 6 was used in substantially the same manner except that 0 part by weight was used.
Got Then, using the black toner 6, the two-component black developer 6 is used in the same manner as the two-component black developer 1.
Got Table 4 shows the toner formulation and measurement results of physical properties.

When a fixing test and a durability test were conducted in the same manner as in Example 1, almost the same results were obtained. The results are shown in Table 4.
Shown in.

[0164]

Example 7 In Example 1, the aluminum compound of di-tert-butylsalicylic acid (charge control agent) was added to 2.
Black toner 7 was used in substantially the same manner except that 0 part by weight was used.
Got Then, using the black toner 7, in the same manner as the two-component black developer 1, the two-component black developer 7
Got Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. Although the blocking resistance was slightly deteriorated, it was not at a practically problematic level. The results are shown in Table 4.

[0166]

Examples 8 to 11 In Example 1, carbon black (b), (c), instead of carbon black (a),
Black toners 8 to 11 were prepared in the same manner except that (d) and (e) were used, respectively, and two-component black developer 8 was prepared in the same manner as two-component black developer 1.
I got ~ 11. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The results are shown in Table 4. However, with the black toner 8, the solid image was slightly reddish, and the toner was slightly scattered during the durability in the high temperature and high humidity environment.

[0168]

[Example 12] In Example 1, the content of carbon black (a) was 2.
The charging amount was changed so as to be 5 parts by mass, and then the black toner 12 was prepared in the same manner, and the two-component black developer 12 was obtained in the same manner as the two-component black developer 1.
Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. Although the fixability was within the practical level, the image density of the solid portion was poor and the image was poor overall. The results are shown in Table 4.

[0170]

[Example 13] In Example 1, the content of carbon black (a) was 7.
A black toner 13 was prepared in the same manner by changing the charged amount so that the amount was 0 parts by mass, and a black developer 13 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. In durability under high temperature and high humidity environment, toner scattering began to stand out from the latter half of durability. On the other hand, in the fixing test under the normal temperature and normal humidity environment, the black toner 13 had a poor level of transfer blur in the solid portion and could not be greatly improved even if the transfer conditions were changed. However, the transferability was within the practical level. The results are shown in Table 4.

[0172]

Examples 14 to 17 In place of the purified normal paraffin (A) in Example 1, waxes (B), (C),
Black toners 14 to 17 were prepared in the same manner except that (D) and (E) were used, and black developers 14 to 1 were prepared in the same manner as the two-component black developer 1.
Got 7. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The black toner 17 had a deteriorated offset resistance level on the high temperature side, and although the fixing width was narrow, it was somehow within a practical level. The results are shown in Table 4.

[0174]

Example 18 A black toner 18 was obtained in substantially the same manner as in Example 1 except that 4 parts by mass of the zinc compound of di-tert-butylsalicylic acid was used.
A black developer 18 was obtained using the black toner 18 in the same manner as in the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. Although the blocking resistance was slightly deteriorated, it was not at a practically problematic level. In the fixing test,
The offset generation temperature on the high temperature side was about 30 ° C. lower than that of the black toner 1 described in Example 1, but it was within a practical level. The results are shown in Table 4.

At the time of running 10,000 sheets under a low temperature and low humidity environment, the black toner 18 showed a charge-up tendency, and the image density tended to gradually decrease with running. However, it was within a practical level.

[0177]

Example 19 Black toner particles (classified product) having a weight average particle size in the particle size distribution of 4.8 μm were obtained in substantially the same manner as in Example 1. For the purpose of flowability improvement and charging characteristics _{imparted, i-C 4 H 9 Si} (OCH 3) 3: treated with hydrophobic aluminum oxide 23 parts by mass (BET180m ² /
1.2 parts by mass of g) was combined with 100 parts by mass of the above black toner particles to prepare a black toner 19.
Then, using the black toner 19, the two-component black developer 19 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was almost the same as that of the toner of Example 1, but a charge-up tendency was observed in a durability test of 10,000 sheets under a low temperature and low humidity environment, but it was within a practical level.
The results are shown in Table 4.

[0179]

Example 20 Black toner particles (classified product) having a weight average particle size in the particle size distribution of 9.8 μm were obtained in substantially the same manner as in Example 1. The hydrophobic aluminum oxide used in Example 1 was combined with 0.8 parts by mass of 100 parts by mass of the black toner particles to prepare a black toner 20.
Then, using the black toner 20, the two-component black developer 20 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was almost the same as that of the toner of Example 1, but the halftone reproducibility was slightly deteriorated in the image output in a low temperature and low humidity environment, and a crisp image was obtained as a whole. However, it was within a practical level. The results are shown in Table 4.

[0181]

Example 22 Black toner particles (classified product) having a weight average particle size in the particle size distribution of 3.9 μm were obtained in substantially the same manner as in Example 1. The hydrophobic aluminum oxide used in Example 1 was used for the purpose of improving fluidity and imparting charging characteristics.
1.4 with respect to 100 parts by mass of the black toner particles
By combining the parts by mass, a black toner 21 was obtained. Then, using the black toner 20, the two-component black developer 20 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was 10 ° C. on the low temperature side and 20 ° C. on the high temperature side as compared with the toner of Example 1, but almost the same results were obtained. However, in a durability test of 10,000 sheets under a low temperature and low humidity environment, a charge-up tendency was observed, and the concentration decreased with the durability, and some fog was observed during the durability. However,
The fogging was somehow within the practical level. The results are shown in Table 4.

[0183]

Example 22 Black toner particles (classified product) having a weight average particle size in the particle size distribution of 10.5 μm were obtained in substantially the same manner as in Example 1. The hydrophobic aluminum oxide used in Example 1 was added to 100 parts by mass of the black toner particles for the purpose of improving fluidity and imparting charging characteristics.
The black toner 22 was obtained by combining 0.6 parts by mass. Then, using the black toner 22, the two-component black developer 22 was obtained in the same manner as the two-component black developer 1.
Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was 10 ° C. on both the low temperature side and the high temperature side as compared with the toner of Example 1, but showed the same tendency. However, the halftone reproducibility and the fine line reproducibility were reduced in the image output in a low temperature and low humidity environment, and a sharp image was obtained as a whole. However, it was within a practical level. The results are shown in Table 4.

[0185]

Comparative Example 1 Black toner 23 was obtained in substantially the same manner as in Example 1 except that hybrid resin (4) was used instead of hybrid resin (1). Then, using the black toner 23, a two-component black developer 23 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. With the black toner 23, the low temperature fixability was significantly deteriorated. The results are shown in Table 4.

[0187]

Comparative Example 2 A black toner 24 was obtained in substantially the same manner as in Example 1 except that the polyester resin (6) was used instead of the hybrid resin (1). Then, using the black toner 24, a two-component black developer 24 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test was conducted in the same manner as in Example 1. The black toner 24 was wound around the upper roller at a low temperature (150 ° C.) in the same fixing test. The results are shown in Table 4.

[0189]

Comparative Example 3 A black toner 25 was obtained in the same manner as in Example 1 except that the aluminum compound of di-tert-butylsalicylic acid (charge control agent) was not used. Then, using the black toner 25, in the same manner as the two-component black developer 1, the two-component black developer 25
Got Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test was conducted in the same manner as in Example 1. The black toner 25 was wound around the upper roller at 130 ° C., and the durability evaluation was not performed. The value of the average primary particle diameter of the carbon black by the cross-sectional TEM observation of the toner was larger than that of the black toner of Example 1.

[0191]

Comparative Example 4 A black toner 26 was obtained in the same manner as in Example 1 except that the wax (A) was not used.
Then, using the black toner 26, a two-component black developer 26 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test was conducted in the same manner as in Example 1. The black toner 26 was wound around the upper roller at 130 ° C., and the durability evaluation was not performed.

[0193]

Comparative Example 5 A black toner 27 was obtained in the same manner as in Comparative Example 1, except that 0.45 parts by mass of carbon black (a) was contained with respect to 100 parts by mass of the binder resin. Then, using the black toner 27, a two-component black developer 27 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties. A fixing test and a durability test were conducted in the same manner as in Example 1. High image density could not be obtained even when images were produced by changing the developing conditions.

[0194]

Comparative Example 6 A black toner 28 was obtained in the same manner as in Comparative Example 2, except that the carbon black (a) was contained in an amount of 10.2 parts by mass based on 100 parts by mass of the binder resin. Then, using the black toner 28, a two-component black developer 28 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. With the black toner 28, the fixability on the low temperature side deteriorated, and the temperature had to be raised to 150 ° C. When the durability of the black toner 28 was evaluated in a high temperature and high humidity environment, the image had a large amount of fogging from the initial stage. When the durability was further advanced, toner scattering deteriorated, so the durability was interrupted midway.

[0196]

Comparative Example 7 A black toner 29 was obtained in the same manner as in Example 1, except that carbon black (f) was added in place of carbon black (a) in an amount of 3 parts by weight based on 100 parts by weight of the binder resin. It was Then, using the black toner 29, a two-component black developer 29 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was almost the same as that of the toner of Example 1, but the black toner 29 was not suitable as a black toner for forming a full-color image because the solid image was considerably reddish. Further, in the durability under high temperature and high humidity environment, toner scattering occurred from the initial stage, and the level of toner scattering after standing for a long time was not a practical level. The results are shown in Table 4.

[0198]

Comparative Example 8 A black toner 30 was prepared in the same manner as in Example 1 except that 6 parts by mass of carbon black (g) was added to 100 parts by mass of the binder resin instead of carbon black (a). Obtained. Then, using the black toner 30, a two-component black developer 30 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test and a durability test were conducted in the same manner as in Example 1. The fixability was almost the same as that of the toner of Example 1, but with the black toner 30, the level of blurring of the transfer was severe, and the uniformity of the solid image was at an unusable level. The results are shown in Table 4.

[0200]

Comparative Example 9 A black toner 31 was obtained in the same manner as in Example 1 except that 4 parts by mass of a boron compound of benzylic acid was used instead of the aluminum compound of di-tert-butylsalicylic acid (charge control agent). . Then, using the black toner 31, a two-component black developer 31 was obtained in the same manner as the two-component black developer 1. Table 4 shows the toner formulation and measurement results of physical properties.

A fixing test was conducted in the same manner as in Example 1. The black toner 31 was wound around the upper roller at a low temperature (130 ° C.) in the same fixing test. Observation of the cross section of the toner by TEM revealed that the dispersibility of the carbon black in the black toner 31 was deteriorated. That is, many aggregates of carbon black were found. The results are shown in Table 4.

[0202]

[Table 4]

[0203]

The black toner of the present invention is excellent in blocking resistance, storability under high temperature environment, low temperature fixing property, high temperature offset resistance, development stability, 3 environment stability and transferability, It is possible to stably obtain high-definition and high-quality images.

[Brief description of drawings]

FIG. 1 shows an embodiment of an image forming apparatus using a black toner of the present invention.

FIG. 2 is a schematic configuration diagram of a fixing device used in the image forming apparatus of FIG.

[Explanation of symbols]

1 photosensitive drum 2 Primary charger 3 exposure means 4 Developing device 5 Transfer device 6 cleaning device 7 Pre-exposure lamp 8 Paper feeding and transport section 9 Separation means 10 Fixing device 11 Paper output section

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) G03G 9/08 325 331 (72) Inventor Noriyoshi Sugawara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Nozomu Komatsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H005 AA01 AA06 AA15 AA21 CA02 CA08 CA14 CA16 CA25 CB18 DA02 DA06 EA03 EA05 EA07

Claims (10)

[Claims] 1. A black toner containing at least a binder resin, wax and carbon black, wherein the loss elastic modulus G ″ of the black toner has a peak of 50 to 50.
It exists in the temperature range of 70 ° C and has a storage elastic modulus G'of 1 × 1
0 ⁶ temperature T1 at which (dN / m ²⁾ shows a temperature at which the storage modulus G 'indicates the ^{1 × 10 5 (dN / m} 2) T2
Then, T1 is in the temperature range of 85 to 105 ° C., and ΔT = T2−T1 ≧ 20 ° C., and the black toner is carbon black binding resin 1
The black toner contains 0.5 to 10 parts by mass per 100 parts by mass, and the average primary particle diameter of carbon black measured by TEM observation of the cross section of the black toner is 14 to 60 nm. 2. The black toner according to claim 1, wherein ΔT ≧ 25 ° C. 3. The differential thermal analysis (D) is used for the black toner.
SC) endothermic curve in measurement, temperature 30 ~ 20
It has one or more endothermic peaks in the range of 0 ° C., and the peak temperature of the maximum endothermic peak among the endothermic peaks is 60 to 110.
The black toner according to claim 1, which is in a range of ° C. 4. The black toner according to claim 1, wherein the black toner contains a metal compound of an aromatic carboxylic acid derivative. 5. The black toner according to claim 4, wherein the metal compound of the aromatic carboxylic acid derivative is an aluminum compound of the aromatic carboxylic acid derivative. 6. The binder resin comprises (a) a polyester resin, (b) a hybrid resin having a polyester unit and a vinyl copolymer unit, and (c) a hybrid resin and a vinyl copolymer. A resin selected from the group consisting of a mixture, a mixture of (d) a polyester resin and a vinyl copolymer, and (e) a mixture of a hybrid resin and a polyester resin.
5. The black toner according to any one of item 5. 7. The average primary particle size of carbon black measured by a cross-sectional TEM observation of the black toner is:
The black toner according to any one of claims 1 to 6, which has a thickness of 17 to 55 nm. 8. The average primary particle size of carbon black measured by a cross-sectional TEM observation of the black toner is:
It is 20-50 nm, The black toner as described in any one of Claims 1-6 characterized by the above-mentioned. 9. The weight average particle diameter of the black toner is
It is 4-10 micrometers, The black toner as described in any one of Claims 1-8 characterized by the above-mentioned. 10. The black toner according to claim 1, wherein the black toner is a black toner for forming a full-color image that reproduces a multicolor image.