JP2001109201A - Positive charge type electrostatic charge image developing toner and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide positive charge type electrostatic charge image developing toners which exhibit a stable electrostatic charge behavior in multiple sheet printing without the generation of the splashing toners and have excellent heat roll fixability and offset characteristic and with which high-quality images having excellent wear resistance may be obtained. SOLUTION: The positive charge type electrostatic charge image developing toners are the toners containing a binder resin, coloring agents, a positive charge type charge control agent and a release agent, contains wax consisting of the components secreted by scale insects in the release agent and further preferably contains a nigrosine dye and/or quaternary ammonium salt compound as the positive charge type charge control agent and the electrostatic charge image developer using the same.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developer used in an electrophotographic method, an electrostatic recording method, or an electrostatic printing method.

[0002]

2. Description of the Related Art As an electrophotographic method, US Pat.
No. 97,691, JP-B-42-23910 and JP-B-43-24748, various methods are described. Usually, various methods are described on an electrostatic latent image carrier such as a photoconductive photoreceptor. An electrostatic latent image is formed by charging and exposure, and then the electrostatic latent image is developed with a toner composition containing a colorant in a binder resin, and the obtained toner image is transferred to a support such as transfer paper. In general, a visible image is formed by fixing.

[0003] Further, many methods are known as a developing method in electrophotography, but when roughly classified, fine particles (20 to 500) such as iron powder, ferrite, nickel, and glass are used.
μm) as a developer, and a one-component development method using a developer consisting of only the toner.

Typical examples of the two-component developing method include a cascade method described in US Pat. No. 2,618,552 and a magnetic brush method described in US Pat. No. 2,874,063.
In these methods, the carrier shares functions such as agitating, transporting, and charging the developer, and the function separation between the carrier and the toner is clear. For this reason, it is widely used at present because charge control of the toner and formation of the developer layer are relatively easy, and high-speed operation is possible.

[0005] With the development of the information society in recent years, in each field of electrophotography, electrostatic recording, and electrostatic printing, high quality of printed images, high speed of recording, high density, and long-term storage stability have been achieved. Demands for improvement of toner characteristics for recording an electrostatic latent image on a printing medium have been greatly increased. In particular, in toners for two-component developers suitable for high-speed printing, the mechanical strength to withstand friction with the carrier, stable fixing behavior in a wide temperature range in the heat roll fixing method, stable charging behavior in multi-copy printing, Eliminating scattered toner that does not contaminate the inside of the machine even during long-term use is an important issue, and these issues depend very much on the properties of the binder resin, release agent, and charge control agent used in the toner composition. large.

Hitherto, as binder resins for toners, polystyrene, styrene-acrylate copolymer, styrene-butadiene copolymer, polyester,
Epoxy resins, polybutyral resins, xylene resins, coumarone indene resins, and the like have been researched and used, and various proposals have been made in designing these resins depending on the application.

In general, there are various characteristics required for the binder resin, such as charging and fixing characteristics. Particularly, the binder resin used for the toner for heat roll fixing includes a transfer paper. Improvements in fixing performance and anti-offset performance are required. In the heat roll fixing, the toner particles electrostatically attached to the transfer paper are pressed,
It is melted and fixed on the transfer paper by passing between heated heat rolls. However, at this time, if the surface temperature of the roll is too low, the entire toner particle layer is not sufficiently heated,
Only the surface in contact with the heating roll softens and adheres to the heating roll. Since the toner on the transfer paper side is not softened, no adhesive force is generated, and as a result, most of the toner layer on the transfer paper is transferred to the fixing roll side without being fixed to the transfer paper. This is called a cold offset.

Conversely, if the temperature of the roll surface is too high, the viscosity of the melted toner decreases. Along with this, the internal cohesive force of the melted toner layer also sharply decreases and falls below the adhesive force to the heating roll. As a result, the melted toner layer breaks and moves to both the transfer paper and the fixing roll. This is called hot offset and causes the contamination of the heating roll. The toner adhered to the heat roll is re-transferred to the transfer paper and stains the non-image area, thereby lowering print quality.

The anti-offset performance means that the toner has the ability to prevent cold offset or hot offset at a certain temperature, and the binder resin for toner has anti-offset performance over a wide temperature range, and It is required to have excellent fixing characteristics.

Numerous design examples have been proposed to achieve the above objects. Among them, in order to maintain the viscoelasticity at the time of heating and melting, or to suppress the viscosity change due to temperature fluctuation, the molecular weight distribution is increased and the crosslinking is increased. Techniques for providing a structure, applying a rubber elastic material, and the like have been studied.
However, in the conventionally proposed invention, a resin which sufficiently satisfies the anti-offset performance and fixing performance in a wide temperature range currently required has not been obtained.

In order to compensate for this, techniques relating to a release agent for imparting releasability from a heat roll at the time of fixing and preventing occurrence of offset have been studied in parallel. Until now, synthetic waxes such as polypropylene wax and polyethylene wax have been mainly studied, but no wax which sufficiently satisfies the offset resistance and the fixing performance in a wide temperature range has been obtained.

Various charge control agents have been studied so far. Nigrosine dyes and quaternary ammonium are used as charge control agents for positively chargeable toners used in machines using high-speed, high-durability selenium photoreceptors. Salt compounds and the like are known. Examples of the use of these positively chargeable charge control agents alone or in combination are disclosed in JP-A-1-25
No. 9371, JP-A-3-7948, JP-A-5-119
509 and JP-A-10-246991.

However, these reports do not disclose results satisfying all the characteristics required for the above-described toner for high-speed printing.

[0014]

DISCLOSURE OF THE INVENTION The present invention provides a high image quality which exhibits stable charging behavior in multi-copy printing without generating scattered toner, has excellent heat roll fixability and offset resistance, and has excellent wear resistance. High durability for obtaining images
An object of the present invention is to provide a long-life positively chargeable electrostatic image developer.

[0015]

Means for Solving the Problems The present inventors have conducted intensive studies on various release agents and as a result, the above-mentioned problems have been solved by combining a specific wax and a positively chargeable charge control agent having a specific structure. I found what I could do.

That is, in order to solve the above-mentioned problems, the present invention provides a toner comprising at least a binder resin, a colorant, a positively chargeable charge control agent and a release agent, wherein the release agent is An object of the present invention is to provide a toner for developing a positively chargeable electrostatic image, comprising a wax composed of a component secreted by a scale. Further, in order to solve the above-mentioned problems, the present invention provides an electrostatic charge comprising a colored resin particle containing at least a binder resin, a colorant, a positively chargeable charge control agent and a release agent, and a resin-coated magnetic carrier. An image developer, wherein the release agent comprises a wax composed of a component secreted by a scale insect.

The scale insect wax used in the present invention can be obtained by dissolving the waxy component secreted by the larvae of the scale insect (also known as rotifer) in, for example, boiling water, separating the upper layer, cooling and solidifying, or repeating the process. it can. The scale insect wax purified by such a means is white in a solid state, has an extremely sharp melting point, and is suitable as a toner wax in the present invention. The acid value is reduced to 10 or less due to purification, and is preferably 5 or less for toner.

Conventionally used synthetic waxes such as polyethylene wax and polypropylene wax, as well as other petroleum waxes and natural waxes can be used in combination as long as the gist of the present invention is not impaired.

[0019]

The binder resin used in the present invention can be used without any particular limitation as long as it is generally used as a binder resin in a toner. For example, polystyrene, styrene -(Meth) acrylic acid ester copolymers, olefin resins, polyester resins, amide resins, carbonate resins, epoxy resins, graft polymers thereof, and mixtures thereof.

Among them, in consideration of charge stability, storage stability, fixing characteristics, and color reproducibility when used as a resin for a color toner containing a chromatic organic pigment, etc., polyester resin, styrene- ) Acrylic ester copolymer resins can be suitably used.

The polyester resin used in the present invention comprises:
For example, it is obtained by dehydrating and condensing a dicarboxylic acid and a diol by a usual method. As dicarboxylic acids, for example, phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid,
Adipic acid, maleic acid, maleic anhydride, fumaric acid,
Examples thereof include dicarboxylic acids such as itaconic acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, and sebacic acid, and derivatives thereof.

Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, hexanediol, bisphenol A, and polyoxyethylene.
(2.0) -2,2-bis (4-hydroxyphenyl)
Propane and its derivatives, polyoxypropylene
(2.0) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene-
(6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.4)- 2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.
3) -2,2-bis (4-hydroxyphenyl) propane and derivatives thereof.

Further, for example, polyethylene glycol,
Diols such as polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, and polycaprolactone diol can also be used.

Further, if necessary, a trifunctional or higher functional aromatic carboxylic acid such as trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride or a derivative thereof, or sorbitol, 1,2,3 , 6-hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,2,4-butanetriol,
Trifunctional or higher alcohols such as 5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trimethylolbenzene Or bisphenol A epoxy resin, bisphenol F epoxy resin, ethylene glycol diglycidyl ether, hydroquinone diglycidyl ether, N, N-diglycidylaniline, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane Triglycidyl ether, pentaerythritol tetraglycidyl ether, cresol novolak type epoxy resin, phenol novolak type epoxy resin, vinylation with epoxy group Product or copolymer, epoxidized resorcinol-acetone condensate, partially epoxidized polybutadiene, semi-dry or dry fatty acid ester epoxy compound, etc. You can also.

The polyester resin in the present invention can be obtained by performing a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components in the presence of a catalyst.
The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

As a catalyst for carrying out the above reaction, for example, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate and the like can be appropriately used.

The polyester resin used in the present invention only needs to have a proper glass transition point and melt viscosity characteristics as a two-component developing toner, and the viscosity is 1 × 10 ^5.
Those having a poise temperature of 95 ° C. or higher have good fixability, and among them, those having a viscosity of 1 × 10 ⁵ poise and a temperature of 95 to 170 ° C. are more preferable since they have good fixability at low temperatures. It is particularly preferable that the temperature at which the viscosity becomes 1 × 10 ⁵ poise is 95 to 160 ° C.

On the other hand, those having a glass transition temperature (Tg) of 40 ° C. or higher are preferable, and those having a Tg of 45 to 85 ° C. are particularly preferable.

Further, the acid value is preferably 30 or less, and particularly preferably 10 or less. If the acid value is too high, the charge amount will decrease, and the desired charge amount cannot be obtained.

The styrene monomer used in the styrene- (meth) acrylate copolymer resin used in the present invention includes, for example, styrene, α-methylstyrene, vinyltoluene, p-sulfonestyrene, dimethylaminomethyl There are styrene and the like.

Examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate. Alkyl (meth) acrylates such as meth) acrylate, tertiary butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate; cyclohexyl (meth) acrylate Alicyclic (meth) acrylates such as methacrylate; aromatic (meth) acrylates such as benzyl (meth) acrylate; hydroxyl-containing (meth) acrylates such as hydroxyethyl (meth) acrylate; Phosphoric acid group-containing (meth) acrylates such as riloxyethyl phosphate; halogen atoms such as 2-chloroethyl (meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate and 2,3-dibromopropyl (meth) acrylate (Meth) acrylates; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate; ether group-containing (meth) acrylates such as 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate;
(Meth) acrylates containing a basic nitrogen atom or an amide group, such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate;

Unsaturated compounds copolymerizable therewith can be used if necessary. For example, carboxyl group-containing vinyl monomers such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid; sulfo group-containing vinyl monomers such as sulfoethylacrylamide; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; Vinyl monomers containing a ketone group such as vinyl methyl ketone and vinyl isopropenyl ketone; basic groups such as N-vinyl imidazole, 1-vinyl pyrrole, 2-vinyl quinoline, 4-vinyl pyridine, N-vinyl 2-pyrrolidone and N-vinyl piperidone For example, a vinyl monomer containing a nitrogen atom or an amide group can be used.

A crosslinking agent may be used in the range of 0.1 to 2% by weight based on the vinyl monomer. As the crosslinking agent, for example, divinylbenzene, divinylnaphthalene,
Divinyl ether, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate, 1,3-
Butylene glycol di (meth) acrylate, 1,6-hexane glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di ( (Meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, and the like.

Alternatively, in the case of a resin using a styrene- (meth) acrylate copolymer obtained by copolymerizing the carboxyl group-containing vinyl monomer, a crosslinked resin can be formed by using a metal salt. A as metal salt
l, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, P
b, Sn, Sr, halide such as Zn, hydroxide, oxide,
There are carbonates, carboxylate salts, alkoxylates, chelate compounds and the like. The crosslinking reaction can be carried out by heating and stirring in the presence of a solvent.

As a method for producing the styrene- (meth) acrylic acid ester copolymer, a usual polymerization method can be employed, and the polymerization reaction is carried out in the presence of a polymerization catalyst such as solution polymerization, suspension polymerization, bulk polymerization and the like. Is performed.

As the polymerization catalyst, for example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-yl)
(Carbonitrile), benzoyl peroxide, dibutyl peroxide, butyl peroxybenzoate, and the like, and the amount used is 0.1 to 10.
0% by weight is preferred.

The styrene- (meth) acrylate copolymer resin used in the present invention only needs to have a glass transition point and a melt viscosity characteristic suitable for a two-component developing toner. Those having a temperature of 1 × 10 ⁵ poise at 95 ° C. or higher are preferable because of good fixability, and among them, the temperature at which the viscosity becomes 1 × 10 ⁵ poise is 95 ° C.
Those having a viscosity of 1 to 10 ⁵ poise are more preferable because the fixability at low temperatures is good.

On the other hand, the styrene- (meth) acrylate copolymer resin has a glass transition temperature (Tg) of 40 ° C.
Those described above are preferred, and among them, those having a Tg of 45 to 85 ° C are particularly preferred. The acid value is desirably 30 or less, particularly desirably 15 or less. If the acid value is too high, the charge amount will decrease, and the desired charge amount cannot be obtained.

As the coloring agent, for example, carbon black, various organic pigments, inorganic pigments, dyes and the like are used.
Although not particularly limited, the following are given as examples.

As the coloring agent that can be used in the present invention, well-known coloring agents can be mentioned. Carbon blacks such as furnace black, channel black, acetylene black, thermal black, and lamp black classified according to the production method are used as black colorants, and phthalocyanine C.I. I. PigmentBl
ue 15-3, an indanthrone C.I. I. Pigm
ent Blue 60 and the like, and quinacridone C.I. I. Pigment Red 122,
Azo-based C.I. I. Pigment Red 22, C.I.
I. Pigment Red 48: 1, C.I. I. Pig
Ment Red 48: 3, C.I. I. Pigment
Red 57: 1, etc., and an azo-based C.I. I. Pigment Yellow 12, C.I. I.
Pigment Yellow 13, C.I. I. Pigm
ent Yellow 14, C.I. I. Pigment
Yellow 17, C.I. I. Pigment Yellow
ow 97, C.I. I. Pigment Yellow 1
55, isoindolinone-based C.I. I. Pigment
Yellow 110, a benzimidazolone C.I.
I. Pigment Yellow 151, C.I. I. P
pigment yellow 154, C.I. I. Pigm
ent Yellow 180, C.I. I. Pigment
Yellow 185 and the like. The colorant content is 1
It is in the range from 20 parts by weight to 20 parts by weight. These colorants can be used alone or in combination of two or more.

In the toner of the present invention, the weight ratio of the resin to the colorant is not particularly limited, but usually 1 to 30 parts by weight, preferably 1 to 1 part by weight of the colorant per 100 parts by weight of the resin.
0 parts by mass. The toner composition of the present invention functions as a toner, and is mainly composed of a binder resin and a colorant made of the polyester resin as described above.
Other additives may be included. As an example,
As the lubricant, for example, metal soap, zinc stearate and the like can be used, and as the abrasive, for example, cerium oxide, silicon carbide and the like can be used. When a part or all of the colorant is replaced with magnetic powder, it can be used as a magnetic one-component developing toner. As the magnetic powder, a ferromagnetic metal such as iron, cobalt, and nickel, or a powder of an alloy or a compound such as magnetite, hematite, or ferrite is used. As these magnetic powders, those subjected to a hydrophobic treatment with an organic silicon or a titanium compound or the like, if necessary, are preferably used. The content of the magnetic powder is preferably from 15 to 70% by mass based on the mass of the toner.

In order to produce a color toner using the above-mentioned chromatic colorant, it is desirable to use a polyester resin from the viewpoint of excellent color development and transparency of a color image. Polyester resin is more tough and more resistant to stress in a developing device than styrene acrylic resin, and has a low melting point and is suitable as a resin for color toner.

As the positively chargeable charge control agent used in the present invention, a triphenylmethane dye, a nigrosine dye, a quaternary ammonium salt compound, a resin containing a quaternary ammonium group and / or an amino group, and the like are used. However, it is particularly desirable to use a nigrosine dye and a quaternary ammonium salt compound in combination. As the quaternary ammonium salt compounds, compounds (1) to
It is particularly preferred that it is at least one selected from (3). The compounds having the structure of (1) include Bontron P-
51; (Orient Chemical), but the compound of (2)
P-302, TP-415, TP-610; (made by Hodogaya Chemical).

Compound (1)

Embedded image [Wherein, R _{1 to} R ₃ represent a CnH2n + 1 group. Where n
Represents an integer of 1 to 10. Further, R _{1 to} R ₃ may be the same or different. ]

Compound (2)

Embedded image [Wherein R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, Represents an aralkyl group having 7 to 20 carbon atoms, A ^- is a molybdate anion or a tungstate anion,
Represents a heteropolyacid anion containing molybdenum or tungsten atoms. ]

Compound (3)

Embedded image Wherein m represents 1, 2 or 3, and n represents 0, 1
Or 2, and M is a hydrogen atom or a monovalent metal ion. X and Z each represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R _{8 to} R ₁₅ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, an alkoxylene group having 1 to 4 carbon atoms, or a general formula (-C 2-5 alkylene-O ) N-R
(Where R is hydrogen or an alkyl group or an acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), wherein R ₁₆ , R ₁₇ , R
₁₈ and R ₁₉ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (—CH ₂ —CH ₂ —O) n—R (where R Is hydrogen or an alkyl group or acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), and a mononuclear or polynuclear alicyclic residue having 5 to 12 carbon atoms. Represents a group, a mono- or polynuclear aromatic residue or an araliphatic residue. ]

More specifically, there are the following compounds.

(1-1)

Embedded image

(2-1)

Embedded image

(2-2)

Embedded image

(2-3)

Embedded image

(2-4)

Embedded image

(2-5)

Embedded image

(2-6)

Embedded image

(2-7)

Embedded image

(2-8)

Embedded image

(2-9)

Embedded image

(2-10)

Embedded image

(2-11)

Embedded image

(3-1)

Embedded image

(3-2)

Embedded image

When a nigrosine dye and a quaternary ammonium salt compound are used in combination, the use ratio is preferably 1/9 to 9/1, and more preferably 2/8 to 8/2. Nigrosine dyes have a high positive charge-imparting ability, but are inferior in charging uniformity and stability. When used alone, fogging is likely to occur, resulting in a printed image with insufficient sharpness.
The quaternary ammonium salt compound is excellent in uniformity and stability of charging, but has a low positive charge imparting ability. By using it together with a nigrosine dye rather than using it alone, clear printing without fogging during continuous printing An image is obtained stably.
If the use ratio of the nigrosine dye is lower than 1, the toner cannot be sufficiently charged, and the transfer efficiency to paper decreases. As a result, an image having poor solid portion uniformity and poor image resolution is obtained. Further, toner scattering increases due to the low charge. When the use ratio is more than 9, the charge amount becomes too high, and the developer becomes a low-density and low-image-quality developer with a lot of fog in continuous printing. As described above, if either one of them is too large or too small, an optimal charge amount cannot be obtained, and as a result, a printed material having low density and low image quality is obtained, and a developer in which toner scattering occurs is obtained.
By optimally adjusting the ratio of the two, an optimal charge amount can be obtained, and a long-life developer free of toner scattering that enables high-density and high-quality printing without fogging, clear image outlines, Obtainable.

The content of the charge control agent is determined by the binder resin 10
It is preferably used in an amount of 0.3 to 10 parts by mass, more preferably 1 to 5 parts by mass, per 0 parts by mass.

The toner of the present invention can be obtained by an extremely general manufacturing method without depending on a specific manufacturing method.
For example, it can be obtained by melt-kneading a resin and a colorant at a temperature equal to or higher than the melting point (softening point) of the resin, followed by pulverization and classification.

Specifically, for example, the above-mentioned resin and colorant are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader or a twin-screw extruder. At this time, the colorant may be uniformly dispersed in the resin, and the conditions for the melt-kneading are not particularly limited, but are usually from 80 to 180 ° C. for from 30 seconds to 2 hours. The coloring agent may be previously subjected to a flushing treatment so as to be uniformly dispersed in the resin, or a master batch melt-kneaded with the resin at a high concentration.

Then, after cooling, the mixture is finely pulverized by a pulverizer such as a jet mill and classified by an air classifier or the like.

The average particle diameter of the particles constituting the toner base is as follows:
Although not particularly limited, it is usually adjusted to be 5 to 15 μm.

Usually, an external additive is mixed with the thus obtained toner base using a mixer such as a Henschel mixer.

The external additives are used for modifying the surface of the toner matrix such as improving the fluidity and charging characteristics of the toner. For example, inorganic fine powders such as silicon dioxide, titanium oxide and alumina and silicone oils are used. What has been subjected to a surface treatment with a hydrophobizing agent such as, or a fine resin powder is used.

Examples of silica include those having hydrophobicity and the like among silicon dioxides, and examples thereof include those obtained by subjecting silicon dioxide to surface treatment with various polyorganosiloxanes, silane coupling agents and the like. For example, there is one that is commercially available under the following trade names.

AEROSIL R972, R974, R202, R805, R812, RX200, RY200, R809, RX50, RA200HS, RA200H [Nippon Aerosil Co., Ltd.] WACKER HDK H2000, H2050EP HDK H3050EP, HVK2150 [Wacker Chemicals East Asia Ltd.] Nipsil SS-10, SS-15, SS-20, SS-50, SS-60, SS-100, SS-50B, SS-50F, SS-10F, SS-40, SS-70, SS-72F, [ Nippon Silica Industry Co., Ltd.] CABOSIL TG820F [Cabot Specialty Chemicals, Inc.]

The proportion of the external additive used is usually 0.05 to 5% by mass, preferably 0.1 to 3% by mass, based on the toner matrix.
% By mass.

These silicas have different average particle sizes.
More than one species may be used in combination. The use ratio of silica is usually 0.05 to 5% by mass, and preferably 0.1 to 3% by mass, based on the toner matrix.

The electrostatic image developer of the present invention comprises a toner containing colored resin particles, and a magnetic carrier whose surface is coated with a resin.

The carrier core agent used in the present invention may be iron powder, magnetite,
Ferrite and the like can be used, and among them, ferrite or magnetite, which has a low true specific gravity, high resistance, excellent environmental stability, and is easily formed into a spherical shape, and has good fluidity, is preferably used. The shape of the core agent can be used without any particular problem, such as spherical or amorphous. Average particle size is generally 10 to 500
μ, but 30 to 8 to print a high-resolution image.
0 μ is preferred.

Examples of the coating resin for covering these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, and vinyl chloride. / Vinyl acetate copolymer, styrene / acrylic copolymer, straight silicone resin comprising organosiloxane bond or its modified product, fluororesin, (meth) acrylic resin, polyester, polyurethane, polycarbonate, phenolic resin, amino resin, melamine resin , Benzoguanamine resin, urea resin, amide resin, epoxy resin and the like can be used. Among these, silicone resin, fluororesin, and (meth) acrylic resin are particularly excellent in charge stability and coating strength, and can be more preferably used. That is, the resin-coated carrier used in the present invention is a resin-coated magnetic carrier coated with at least one resin selected from silicone resin, fluororesin, and (meth) acrylic resin using ferrite or magnetite as a core agent. Is preferred.

The method of coating the surface of the carrier core material with the resin is not particularly limited, but a dipping method of dipping in a solution of the coating resin, a spray method of spraying the coating resin solution onto the surface of the carrier core material, or a carrier method. Fluidized bed method in which the carrier is sprayed while being floated by flowing air, a kneader coater method in which a carrier core material and a coating resin solution are mixed in a kneader coater, and a solvent is removed.

The solvent used in the coating resin solution is not particularly limited as long as it dissolves the coating resin. For example, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and the like can be used. The thickness of the coating layer on the carrier surface is usually 0.1
~ 3.0μ.

The mass ratio of the toner containing the colored resin particles to the resin-coated magnetic carrier is not particularly limited, but is usually 0.5 to 0.5% per 100 parts by mass of the carrier.
5 parts by mass.

[0080]

DETAILED DESCRIPTION OF THE INVENTION At least a binder resin, a colorant,
A toner comprising a positively chargeable charge control agent and a release agent, wherein the release agent comprises a wax consisting of a component secreted by the scales. . 2. 2. The toner for developing a positively chargeable electrostatic image according to the above item 1, wherein the toner contains a nigrosine dye and / or a quaternary ammonium salt compound as the positively chargeable charge control agent. 3. 3. The toner according to claim 2, wherein the quaternary ammonium salt compound is at least one selected from compounds (1) to (3) having the following structures. Compound (1)

Embedded image [Wherein, R _{1 to} R ₃ represent a CnH _{2n + 1} group. Where n is 1
And an integer of 10 to 10. Further, R _{1 to} R ₃ may be the same or different. Compound (2)

Embedded image [Wherein R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, Represents an aralkyl group having 7 to 20 carbon atoms, A ^- is a molybdate anion or a tungstate anion,
Represents a heteropolyacid anion containing molybdenum or tungsten atoms. Compound (3)

Embedded image Wherein m represents 1, 2 or 3, and n represents 0, 1
Or 2, and M is a hydrogen atom or a monovalent metal ion. X and Z each represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R _{8 to} R ₁₅ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, an alkoxylene group having 1 to 4 carbon atoms, or a general formula (-C 2-5 alkylene-O ) N-R
(Where R is hydrogen or an alkyl group or an acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), wherein R ₁₆ , R ₁₇ , R
₁₈ and R ₁₉ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (—CH ₂ —CH ₂ —O) n—R (where R Is hydrogen or an alkyl group or acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), and a mononuclear or polynuclear alicyclic residue having 5 to 12 carbon atoms. Represents a group, a mono- or polynuclear aromatic residue or an araliphatic residue. ] 4. An electrostatic image developer comprising at least a colored resin particle containing a binder resin, a colorant, a positively chargeable charge control agent and a release agent, and a resin-coated magnetic carrier, wherein the release agent is a scale insect A positively-chargeable electrostatic image developer comprising a wax composed of a component secreted by a toner. 5. 4. The resin-coated magnetic carrier according to item 4, wherein the resin-coated magnetic carrier is a resin-coated magnetic carrier coated with at least one resin selected from a silicone resin, a fluororesin, and a (meth) acrylic resin.
The positively chargeable electrostatic image developer as described in the above.

[0081]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “%” represents “% by mass” unless otherwise specified.

(Resin Synthesis Example 1) Terephthalic acid 2.0 mol part Isophthalic acid 2.5 mol part Trimellitic acid 0.5 mol part Polyoxyethylene- (2.0) -2,2-bis (4-hydroxy) Phenyl) propane 4.0 mol part Ethylene glycol 1.2 mol part is put into a four-necked flask equipped with a stirrer, a condenser, and a thermometer.
The reaction was carried out at 220 ° C. for 15 hours while adding 07 parts by weight of dibutyltin oxide and removing water generated by dehydration condensation. The softening temperature of the obtained polyester resin is 155 ° C. by ring and ball softening point measurement method, and T
g was 62 ° C., and the acid value was 10.

(Resin Synthesis Example 2) A polyester resin of Resin Synthesis Example 2 was produced in the same manner as in Resin Synthesis Example 1 using the following raw materials. Terephthalic acid 2.5 mol parts Isophthalic acid 2.5 mol parts Trimethylolpropane 0.5 mol parts Polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane 3.5 mol parts Ethylene Glycol 1.0 mol part The softening temperature of the resin obtained by ring-ball softening point measurement is 1
At 50 ° C., Tg by DSC was 61 ° C., and the acid value was 6.

(Resin Synthesis Example 3) Styrene 320 parts by mass butyl acrylate 60 parts by mass methacrylic acid 20 parts by mass Azobisisobutyronitrile 4 parts by mass Xylene 600 parts by mass

Was placed in a round bottom flask and reacted at 80 ° C. for about 10 hours in a nitrogen gas atmosphere, followed by heating to 130 ° C. to terminate the polymerization. Thereafter, 12 parts by weight of aluminum isopropoxide was added, and the mixture was reacted for about 1 hour.
The mixture was heated to 0 ° C. and the pressure was reduced to 0.5 mmHg with a vacuum pump to remove the solvent.

The obtained chelate crosslinked styrene acrylic resin had a softening temperature of 145 ° C. by a ring and ball softening point measurement method.
Tg according to the DSC method was 61 ° C., and the acid value was 5.

(Example 1) 92 parts by mass of the resin of Resin Synthesis Example 1 carbon black “Black Pearls 460 (manufactured by Cabot Specialty Chemicals, Inc.)” 5 parts by mass Coleoptera wax “purified snow wax No. 1 (Seralica Noda) 2) parts by mass Charge control agent (positive charge control agent) "Bontron N-04 (manufactured by Orient Chemical Industry Co., Ltd.)" 1.5 parts by mass "quaternary ammonium salt compound (2 -2) 1.5 parts by mass are mixed with a Henschel mixer and kneaded with a twin-screw kneader. The kneaded material thus obtained was pulverized and classified to obtain “toner material A” having a volume average particle diameter of 10.1 μm.

100 parts by mass of the above-mentioned “toner raw material A” 1 part by mass of silica HDK3050EP (Wacker Chemicals Co., Ltd.) was mixed with a Henschel mixer and then sieved to obtain “toner A”.

<Adjustment of Developer> 5 parts by mass of “Toner A” 95 parts by mass of carrier (silicone resin-coated ferrite carrier) were mixed and stirred to prepare “Developer A”.

In the same manner, toners were prepared in accordance with the formulations shown in Table 1, and developer A (Example 1) to developer I (Example 9) and developer J (Comparative Example 1) to developer L (Comparative Example) 3) was manufactured. The developer I is a magnetic powder BL-200 as a coloring agent.
(Titanium Kogyo) 40 parts. A magnetic one-component developer was used without being mixed with a carrier (a ferrite carrier coated with a silicon resin).

[0091]

[Table 1] Viscole 550P; Polypropylene wax PE-130 manufactured by Sanyo Chemical Co., Ltd .; Polyethylene wax manufactured by Clariant Japan Co., Ltd. Jojoba wax; carbon number 40 to 42 collected from jojoba seeds
Obtained by hydrogenating jojoba oil containing

With respect to the developers obtained in the above Examples and Comparative Examples, a fixing start temperature, a hot offset start temperature, and a printing test were performed as follows.

(Evaluation of Heat Roll Fixing / Offset Performance) An unfixed image sample of A-4 paper size was prepared using a commercial copier remodeling machine, and the fixing start temperature and offset were determined using a heat roll fixing unit having the following specifications. The phenomenon was confirmed. With respect to the toner of Example 9, an unfixed image sample was prepared by modifying a commercially available magnetic one-component developing printer.

[0094]

The fixing strength was determined based on the image density remaining ratio calculated by the following equation. Image density is Macbeth image densitometer RD-
918.

Image density residual ratio = image density after fastness test / image density before left test Here, the image density after fastness test is a Gakushin type friction fastness tester (load: 200 g, rubbing operation: 5 strokes) , Friction element: Whatman filter paper No. 42).

The fixing strength was set to a practically acceptable level when the residual ratio was 80% or more, and the lowest temperature was used as the fixing start temperature. The offset start temperature was a temperature at which the offset phenomenon was visually observed when the fixed image sample was observed.

(Printing Test) The printing quality of continuous printing was evaluated using a commercially available laser beam printer (with a selenium photosensitive member), and the charge amount of the developer was measured. The charge amount was measured by a blow-off charge amount measuring device. The image density was measured with a Macbeth densitometer RD-918, and the background stain was determined by subtracting the white paper density before printing from the white background density. The toner of Example 9 was tested by modifying a commercially available magnetic one-component developing printer. Regarding the charge amount, a toner is collected from the inside of the developing device for each number of printed sheets, a developer is prepared with toner / carrier (silicone resin-coated ferrite carrier) = 5/95 (weight ratio), and another two-component developer is prepared. It measured similarly to. (Toner scattering amount)

Observing the inside of the machine after printing 50KP (50,000 sheets), ○ indicates that there is almost no dirt due to scattered toner around the photosensitive member and the peripheral portion of the developing device, Δ indicates that slight dirt has occurred, and severe dirt has occurred. The case where the test was performed was evaluated as x.

The above evaluation results are shown in Tables 2, 3 and 4.

[0101]

[Table 2]

[0102]

[Table 3]

[0103]

[Table 4] The indications in the table are as follows. * "Charge amount"; μC / g * "Stain evaluation" ○: less than 0.01, Δ: 0.01 to less than 0.03,
×: 0.03 or more * “Toner scattering”; visual observation after printing 50 KP (50,000 sheets) ○: almost no scattering △: slight scattering caused by contamination ×: severe scattering occurred

As is evident from Tables 2, 3 and 4, the positively chargeable electrostatic image developer containing a wax composed of a component secreted by a scale insect according to the present invention has a fixing property and a high temperature property. In addition to being excellent in offset resistance, the developer has a high image density and a stable charging behavior even in a continuous printing test without background contamination and toner scattering.

[0105]

As shown in the above examples, according to the present invention, by using a positively chargeable charge controlling agent and a wax composed of a component secreted by a scale, a good charge can be obtained in a wider temperature range. A developer exhibiting fixing characteristics and offset resistance is obtained. Further, at the same time, it is possible to provide a developer that exhibits stable charging behavior and can stably perform high-density and high-quality printing without fogging without causing toner scattering.

Claims (5)

[Claims] 1. A toner comprising at least a binder resin, a colorant, a positively chargeable charge controlling agent and a release agent, wherein the release agent contains a wax composed of a component secreted by the scale. A toner for developing a positively chargeable electrostatic image, comprising: 2. The toner for developing a positively chargeable electrostatic image according to claim 1, further comprising a nigrosine dye and / or a quaternary ammonium salt compound as the positively chargeable charge control agent. 3. The positively chargeable electrostatic image development according to claim 2, wherein the quaternary ammonium salt compound is at least one selected from compounds (1) to (3) having the following structure. toner. Compound (1) [Wherein, R _{1 to} R ₃ represent a CnH _{2n + 1} group. Where n is 1
And an integer of 10 to 10. Further, R _{1 to} R ₃ may be the same or different. Compound (2) [Wherein R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, Represents an aralkyl group having 7 to 20 carbon atoms, A ^- is a molybdate anion or a tungstate anion,
Represents a heteropolyacid anion containing molybdenum or tungsten atoms. Compound (3) Wherein m represents 1, 2 or 3, and n represents 0, 1
Or 2 and M is a hydrogen atom or a monovalent metal ion. X and Z each represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R _{8 to} R ₁₅ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, an alkoxylene group having 1 to 4 carbon atoms, a general formula (-C 2-5 alkylene-O ) N-R
(Where R is hydrogen or an alkyl group or an acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), wherein R ₁₆ , R ₁₇ , R
₁₈ and R ₁₉ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (—CH ₂ —CH ₂ —O) n—R (where R Is hydrogen or an alkyl group or acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), and a mononuclear or polynuclear alicyclic residue having 5 to 12 carbon atoms. Represents a group, a mono- or polynuclear aromatic residue or an araliphatic residue. ] 4. An electrostatic image developer comprising colored resin particles containing at least a binder resin, a colorant, a positively chargeable charge control agent and a release agent, and a resin-coated magnetic carrier. A positively chargeable electrostatic image developer, wherein the release agent contains a wax composed of a component secreted by the scale insect. 5. The positively charged electrostatic carrier according to claim 4, wherein the resin-coated magnetic carrier is a resin-coated magnetic carrier coated with at least one resin selected from a silicone resin, a fluororesin, and a (meth) acrylic resin. Charge image developer.