JPH04188154A - Electrostatic image developing toner - Google Patents

Abstract

PURPOSE:To form images with stable image quality repeatedly by fixing specific resin fine particles of vinyl to the surface of base material particles where crystalline polyester is bound to amorphous vinyl polymer in the shape of graft or block. CONSTITUTION:In basic material particles graft or block copolymer of crystalline polyester and amorphous vinyl polymer of which glass transition- temperature is 60 deg.C or less is included as binder. To the surface of the particles, vinyl resin fine particles having an average particle dia. of D50 of which Nw/Mn value and softening point Tsp satisfy the formula I where Tg: is glass-transition temp., Nw: weight average molecular amount, Mn: average molecular amount are fixed and the coating ratio should be 10-80%. It is thus possible to form images with stable image quality when such toner is used repeatedly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrostatic image developing toner applied to electrophotography, electrostatic printing, electrostatic recording, etc. The present invention relates to an electrostatic image developing toner comprising fine resin particles.

[Conventional technology]

In an example of electrophotography, an electrostatic image is formed on a photoconductive photoreceptor by charging and exposure, this electrostatic image is developed with toner, and the resulting toner image is transferred to a transfer paper or the like. It is fused to form a visible image.

As the toner image fixing means, a heated roller fixing method is preferably used because it has high thermal efficiency and can perform high-speed fixing. The toner used in this heating roller fixing method is required to have low-temperature fixing properties that allow fixation at lower temperatures, and offset resistance that prevents molten toner from adhering to the surface of the heating roller.

In order to satisfy such conditions of low-temperature fixability and offset resistance, the following techniques have been proposed in the past.

■ JP-A-50-87032 and JP-A-59-3446 disclose a technology that uses a resin consisting of a crystalline resin and an amorphous polymer as a toner binder, as a technology that enables fixing at low temperatures. Proposed.

■ JP-A No. 56-154740 and JP-A No. 57-8549 disclose that a resin consisting of a crystalline resin and an amorphous polymer is used as a toner binder in order to improve fixing properties and anti-offset properties. Some techniques have been proposed to be used as

■ JP-A-63-27855 and JP-A-63-27856 disclose that a block or Techniques have been proposed in which a graft copolymer is used as a toner binder.

On the other hand, toner also satisfies the requirements of anti-blocking property, which allows it to exist stably as a powder without agglomerating under the environmental conditions of use or storage, and anti-filming property, which prevents toner components from adhering to the photoreceptor. It is necessary.

In order to satisfy such requirements for anti-blocking and anti-filming properties, the following techniques have been proposed in the past.

■ JP-A No. 54-2741 discloses that colored particles containing a thermoplastic resin are heated in a gas to soften their surfaces.
A technique has been proposed in which a toner is manufactured by fixing a surface property modifier in the form of particulates to this toner.

■ JP-A-52-84741, JP-A No. 60-186851
No. 60-186852 proposes a technique in which a toner contains a polystyrene additive and a fine powder of an acrylic or acrylic-styrene polymer having an average particle size smaller than that of the toner particles. .

■ Unexamined Japanese Patent Publication No. 63-131149 states that the softening point is 8.
The surface of the heat-fixable base particles having an average particle size of 5 to 25 μm and having a softening point at least 5°C higher than the softening point of the base particles is coated with an average particle size of 0.0°C or lower, a temperature of 110°C or lower than the outflow start temperature, and a softening point of at least 5°C higher than the softening point of the base particles. A technique has been proposed in which small particles mainly composed of an organic polymer substance of 1 μm or more are buried and coated in a size smaller than the particle size of the small particles.

■ JP-A No. 62-226162 discloses colored thermoplastic resin fine particles having a particle size of 2 to 30 μm having an outflow start temperature t+ ('C) in a Koka type flow tester, and the above t+
("C) Fine resin particles with a particle size of 1 μm or less having a higher outflow start temperature tz ("C) at t3 or more and t1
A technique has been proposed in which fine resin particles are attached to the surface of colored thermoplastic resin particles by heat treatment at a temperature lower than 100.degree.

■ JP-A No. 63-25663 discloses that the thermoplastic resin is fused to the surface of the toner main particles by dry mixing the toner main particles, shell-forming thermoplastic resin fine particles, and a charge control agent. A technique has been proposed to form a round shell.

(2) JP-A-63-40169 proposes a technique in which an outer layer not containing a resin having a low average molecular weight is provided around the outer periphery of an inner layer containing a resin having a high average molecular weight and a resin having a low average molecular weight.

■ JP-A No. 63-172279 discloses particles made of a pressure-fixable material having a volume average particle diameter of 1 to 50 μm.
and particles (■) made of a polymeric substance whose volume average particle diameter is 1/10 or less of particles I and whose glass transition temperature or melting point is 40"C or more, so that particles (■) are formed on the surface of particles 1. Adhered composite particles are prepared, and then the composite particles are
A technique has been proposed for producing composite particles having a structure in which particles (1) are fixed to the surface of particles (I) by dispersing them in an air flow of 0 m/s to 300 m/s and applying an impact force.

■ JP-A No. 1-196068 discloses a method consisting of fine particles (A) consisting of a binder, colorant and wax, and fine particles (B) containing at least a resin and having a glass transition temperature of 50°C or higher. A technique has been proposed for toner in which fine particles (B) are fixed or buried in the vicinity of the surface of fine particles (A) by mechanical impact force.

[Problem to be solved by the invention]

However, the above technology (■) has poor blocking resistance;
Another drawback is that offset is likely to occur. Furthermore, there is a drawback that toner tends to film on the photoreceptor, resulting in immediate deterioration of image quality.

In the technique (2) above, the toner has poor fluidity, resulting in poor image quality and significant deterioration in image quality.

The above technique (2) has the disadvantage that the image quality deteriorates when used for a long period of time, both at room temperature and humidity, and at high temperature and high humidity.

In the technique (2) above, the fine particulate surface property modifier is completely embedded in the toner particles and tends to stick, which has the disadvantage of poor blocking resistance and further disadvantages of reduced low-temperature fixing properties of the toner. There is.

In the technique (2) above, since the fine polymer powder is simply mixed, there is a problem that the fine polymer powder easily separates from the toner particles, resulting in poor blocking resistance and fluidity.

Furthermore, loose fine powder electrostatically adheres to the surface of the carrier, hindering the frictional charging between the toner particles and the carrier, resulting in poor image quality such as toner scattering and fogging due to a decrease in the amount of charge on the toner. There is.

In the above techniques ① to ②, by fixing the microscopic resin particles with heat or mechanical impact force, fluidity, storage stability, etc. are improved. It is not possible to satisfy fixing characteristics and durability at the same time, and it is difficult to satisfy all of these characteristics, especially when forming an image using a heated roller fixing device.

An object of the present invention is to provide an electrostatic image that has excellent low-temperature fixing properties, anti-blocking properties, and release properties during fixing, and is capable of forming images with excellent image quality stability when used repeatedly. The purpose of the present invention is to provide developing toner.

[Means to solve the problem]

In order to achieve the above object, the toner for electrostatic image development of the present invention is a graft or block copolymer of a crystalline polyester and an amorphous vinyl polymer, and has a glass transition temperature of 60°C or less. The average particle size is on the surface of the base particle (al) containing as a binder, the glass transition temperature Tg1 the ratio Mw/Mn of the weight average molecular weight Mw and the number average molecular weight Mn, and the softening point Tsp are as follows. It is characterized in that the vinyl resin fine particles (b) satisfying the formula are fixed by mechanical impact force and have a coverage of 10 to 80%.

30nm≦Dso≦5000ffl Tg≧50℃ 5.0≦Mw/Mn≦40 100℃≦Tsp≦160℃ [Specific structure of the invention] Hereinafter, the configuration of the present invention will be specifically explained.

In the present invention, a graft or block copolymer of a crystalline polyester and an amorphous vinyl polymer is used as a binder for the base particles (al).

The crystalline polyester is not particularly limited, but polyalkylene polyester is preferred from the viewpoint of imparting suitable low-temperature fixability and fluidity to the toner.

Such polyalkylene polyesters include polyethylene sebacate, polyethylene adipate, polyethylene adipate, polyethylene succinate, polyhexamethylene sebacate, polyhexamethylene sebacate,
Polyhexamethylene decanedioate, polyoctamethylene dodecanedioate, polynonamethylene azelate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene adipate, polydecamethylene sebacate, polydecamethylene saccharide nate, polydecamethylene dodecanedioate, polydecamethylene octadecanedioate, polytetramethylene sebacate,
Examples include polytrimethylene dodecanedioate, polytrimethylene octadecanedionide, polydecamethylene azelate, polyhexamethylene-decamethylene-sebacate polyoxydecamethylene-2-methyl-1,3-propane-dodecanedioate, etc. .

The melting point Tm of the crystalline polyester is 50% from the viewpoint of further improving the blocking resistance and low-temperature fixing properties of the toner.
~120°C is preferred. Note that the melting point Tm of the crystalline polyester means the melting point in a state where it is not combined with an amorphous vinyl agglomerate.

In addition, this melting point Tm is determined by differential scanning calorimetry (DSC).
It was measured by rDSC-2U (manufactured by Seiko Electronics Industries, Ltd.) according to the following, and the melting peak value when 10 mg of the sample was heated at a constant temperature increase rate (10° C./m1n) was determined as the melting point Tm.

The weight average molecular weight Mw of the crystalline polyester is 5X10'~ from the viewpoint of further improving the offset resistance of the toner.
5X10' is preferred.

In order to further improve the fixing properties and anti-offset properties of the toner, the blending ratio of the crystalline polyester component is preferably 3 to 50% by weight in the graft or block copolymer of the crystalline polyester and the amorphous vinyl polymer.

The main portion of the amorphous vinyl polymer used in the present invention is a vinyl polymer. Examples include polymers polymerized using at least one selected from acid ester monomers.

The styrene monomers include styrene, 〇-methylstyrene, m-methylstyrene, p-methylstyrene,
Examples include α-methylstyrene, p-ethylstyrene, 2,3-dimethylstyrene, 2,4-dimethylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, etc. .

The acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate,
2-chloroethyl acrylate, phenyl acrylate,
Examples include methyl α-chloroacrylate.

The methacrylate monomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, Examples include stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

The amorphous vinyl polymer used in the present invention may be any polymer having a functional group for forming a graft or pro-copolymer with the crystalline polyester. The functional groups include carboxyl group, hydroxyl group, amino group,
Examples include epoxy groups.

Monomers having such functional groups include acrylic acid, β, β-dimethylacrylic acid, α-ethyl acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid,
Crotonic acid, hydroxyethyl methacrylate, phthalic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxyethyl ester, N-hydroxyethyl acrylamide, N-hydroxyethyl methacrylamide, p-aminostyrene, glycidyl methacrylate, and the like. A monomer having such a functional group is used in an amount of 0.1 to 20 mol% of the total monomer composition for obtaining an amorphous vinyl polymer.

The amorphous vinyl polymer used in the present invention is preferably one having ionic crosslinks formed by reacting a polyvalent metal compound with the carboxyl group of a vinyl polymer having carboxyl groups.

The metal element of this polyvalent metal compound is preferably an alkaline earth metal or a zinc group element, particularly Mg.

Zn is preferred.

The polyvalent metal compounds include fluorides, chlorides, chlorates, oxalides, iodides, oxides of the metal elements,
Hydroxide, sulfide, sulfite, sulfate, selenide, telluride, nitride, nitrate, phosphide, phosphinate, phosphate, carbonate, orthosilicate, acetate, oxalate, methyl or lower alkyl metal compounds such as ethyl compounds. Particularly preferred are acetates and oxides of the metal elements.

In order to ionically crosslink a vinyl polymer, for example, the polyvalent metal compound is mixed with a solution containing a vinyl polymer having carboxyl groups obtained by polymerization using a solution polymerization method, and the mixture is heated and reacted. The temperature in the system is 150-180'
It is best to maintain this temperature for more than 1 hour once the temperature reaches about C to simplify the reaction.

Further, from the viewpoint of further improving low-temperature fixability and offset resistance, it is preferable that the amorphous vinyl polymer has at least two maximum values in its molecular weight distribution. That is, it has a molecular weight distribution that can be divided into at least two groups, low molecular weight components and high molecular weight components, and at least 1 in the molecular weight distribution curve measured by gel permutation chromatography (GPC).
It is preferable to have at least two local maxima, such that at least one local maximum lies in the range 2X10' to 2X10' and at least one local maximum lies in the range lX10' to lX10'.

As a method for obtaining such an amorphous vinyl polymer, for example, a first stage polymerization is carried out to obtain either a high molecular weight component or a low molecular weight component, and one of the components thus obtained is combined with the other. By dissolving it in the monomer composition for obtaining the component and carrying out the second stage polymerization, thereby producing the other component, as a result, a polymer having at least two maximum values in the molecular weight distribution curve is obtained. It is possible to obtain union. This two-stage polymerization can be carried out, for example, by a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, or the like.

The above-mentioned high molecular weight component makes the amorphous vinyl polymer even stronger, which prevents the toner particles from being destroyed by external mechanical forces such as friction with the carrier or stirring in the developing device, which causes the filming phenomenon. The generation of fine powder is suppressed. The proportion of high molecular weight components in the amorphous vinyl polymer is preferably 15% by weight or more.

When it is an amorphous vinyl polymer or an ionically crosslinked amorphous vinyl polymer, and is composed of a high molecular weight component and a low molecular weight component as described above, the carboxyl group that reacts with the polyvalent metal compound is It is preferable that it is introduced at least into low molecular weight components. In other words, the destruction of toner particles caused by mechanical external forces such as friction with the carrier or stirring in the developing device is mainly caused by low molecular weight and relatively brittle components in the toner particles. It is preferable to make the toner particles tough by ionic crosslinking, thereby imparting fracture resistance to the toner particles.

In addition, in order to further improve the offset resistance and durability of the toner in the amorphous vinyl copolymer, the value of the ratio Mw/Mn between the weight average molecular weight Mw and the number average molecular weight Mn is preferably 3.5 or more, particularly A range of 4 to 40 is preferred. Here, the Mw and MnO values were measured by GPC under the conditions shown below.

At a temperature of 40° C., a solvent (tetrahydrofuran) is flowed at a flow rate of 1.2 −/min, and a sample solution of 3 mg of tetrahydrofuran with a concentration of 0.2 g/20 − as a sample weight is injected to measure the molecular weight. When measuring the molecular weight of a sample,
Measurement conditions are selected in which the molecular weight of the sample falls within a range in which the logarithm of the molecular weight and the count number of a calibration curve prepared using several types of monodisperse polystyrene standard samples form a straight line.

In addition, the GPC column to be used is not particularly limited as long as it satisfies the above conditions, or for example, TSK-
GEL, GMH (manufactured by Tosoh), etc. are used. Also,
The solvent and measurement temperature are not limited to the above conditions, and may be changed to other conditions as appropriate.

Further, the glass transition temperature Tg of the amorphous vinyl polymer is preferably 50 to 100° C. from the viewpoint of further improving the low-temperature fixing properties, offset resistance, blocking resistance, and durability of the toner. Note that the Tg of the amorphous vinyl polymer means the glass transition temperature in a state where it is not bonded to a crystalline polyester. Moreover, this glass transition temperature Tg is determined by rDSC-according to differential scanning calorimetry (DSC).
20J (manufactured by Seiko Electronics Co., Ltd.). Specifically, 10 mg of the sample was heated at a constant heating rate (10''C/m1n), and the glass transition temperature was determined from the intersection of the baseline and the slope of the endothermic peak.

Further, the softening point Tsp of the amorphous vinyl polymer is preferably 100 to 150° C. from the viewpoint of further improving the low-temperature fixing properties, anti-offset properties, and anti-blocking properties of the toner. This softening point Tsp was measured using a "Koka Type Flow Tester" (manufactured by Shimadzu Corporation). Specifically, 1
A load of 20 kg/cm2 was applied using a plunger while heating a cm2 sample at a heating rate of 6°C/min, and a diameter of 1 m was applied.
m, draw a plunger drop-temperature curve (softening flow curve) of the flow tester by pushing out a nozzle with a length of 1 mm, and when the height of the S-curve is h, h/2
The temperature corresponding to this was defined as the softening point Tsp.

In order to obtain a graft or block copolymer of the crystalline polyester and the amorphous vinyl polymer, they are directly bonded to each other in a head-to-tail manner, for example by a coupling reaction between the terminal functional groups present in each polymer. be able to. Alternatively, it can be bonded to the terminal functional group of each polymer by a bifunctional coupling agent. Such difunctional coupling agents include diisocyanates, dicarboxylic acids, glycols, phosgene, dichlorodimethylsilane, and the like.

In the present invention, it is preferable that the copolymer is contained in a proportion of at least 30% by weight or more, particularly 50% by weight or more of the entire toner. The proportion of crystalline polyester in the copolymer is preferably from 5 to 50% by weight, particularly from 1 to 50% by weight.
0 to 30% by weight is preferred. Furthermore, the softening point of the copolymer is preferably 80 to 130°C, and the glass transition temperature is preferably 30 to 70°C.

In addition to the binder resin, the base particles (al) may appropriately contain a magnetic substance, a colorant, a fixing property improver, a cleaning property improver, a charge control agent, etc., as necessary.

Examples of the magnetic material include compounds exhibiting ferromagnetism such as iron, cobalt, nickel, etc. including ferrite and magnetite. When obtaining a magnetic toner, the content of the magnetic material is 20 to 150 parts by weight per 100 parts by weight of the binder resin.

Colorants include carbon black, chrome yellow,
Examples include DuPont oil red, quinoline yellow, phthalocyanine blue, malachite green offsalate, and the like. The content of the colorant is usually 0.1 to 20 parts by weight per 100 parts by weight of the binder resin.

Fixability improvers include polyolefin, fatty acid ester wax, higher alcohol, paraffin wax,
Softening point (ring and ball method JIS) such as bisamide wax etc.
K 2531-1960) of 60-150''C wax is used.

As cleaning property improvers, fatty acid metal salts, talc,
Stone poku, mica, molybdenum disulfide, zinc oxide, chilium, etc. are used.

As the charge control agent, conventionally known ones can be used, such as nigrosine dyes, metal-containing ab dyes, and the like.

The resin fine particles (bl) used in the present invention are vinyl polymers in structure, and styrene resins, acrylic resins, and styrene-acrylic resins are particularly preferred.

As a method for producing the resin fine particles (b), a general method for producing fine particles such as a suspension polymerization method, an emulsion polymerization method, etc. is used. Alternatively, a so-called soap-free polymerization method may be used in which polymerization is performed using a persulfate-based initiator such as ammonium persulfate.

The resin fine particles fbl used in the present invention have an average particle size of
. is 30 to 500 nm, the glass transition temperature Tg is 50°C or higher, the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn is 5.0 to 40, and the softening point Tsp is 100 to 40. The temperature is 160°C.

By using resin fine particles (BL) that satisfy these conditions, the toner has sufficient low-temperature fixing properties, anti-offset properties, anti-blocking properties, fluidity, and anti-filming properties on photoconductors and developing sleeves. Also, resin fine particles fb
The transfer of l to the carrier surface is effectively prevented, and the stability of the chargeability of the carrier is ensured.

When the average particle diameter DSG of the resin fine particles (b) is less than 30 nm, the blocking resistance of the toner is reduced. On the contrary, the average particle size. If the diameter exceeds 500 nm, resin fine particles (b
It becomes difficult for BL to adhere to the base particles (a), and as a result, the resin fine particles (BL) migrate to the carrier surface, deteriorating the charging property and deteriorating the image quality.

When the glass transition temperature T of resin fine particles (bl) is less than 50°C, the blocking resistance of the toner will be insufficient.

When the ratio Mw/Mn of the resin fine particles (b) is less than 5.0, the offset resistance becomes insufficient. Conversely, the ratio Mw/M
When the value of n exceeds 40, it takes time to produce the resin fine particles (BL), leading to an increase in production cost.

When the softening point Tsp of the resin fine particles (b) is less than 100°C, the offset resistance becomes insufficient. Conversely, the softening point Ts
When p exceeds 160° C., low-temperature fixability becomes insufficient.

In the present invention, the fine resin particles (b) are fixed to the base particles (a) by mechanical impact force.

Specifically, the resin fine particles (BL) are electrostatically adhered to the surface of the base particles (AL) by, for example, light stirring, and then placed in an impact-type crusher or the like, and mechanically The fine resin particles fb) are fixed to the surfaces of the base particles (a) by applying a strong impact force and using a very small amount of frictional heat and impact force generated at this time.

In the present invention, fine resin particles (
The state in which BL is fixed refers to a state in which the height of BL is 10 to 90% of the diameter of the resin fine particles (the height of BL is the resin fine particle fb) protruding from the surface of the base particle (al).
Such a state can be easily confirmed by observing the surface of the toner particles using a transmission electron microscope or a scanning electron microscope.

In order to obtain such a state, in a system where base particles (al) and resin fine particles (b) exist together, base particles (
It is sufficient to apply an impact force of such a magnitude that a) is not crushed, for example, a mechanical impact force of 115 to 1/10 of the force normally required for crushing. Specifically, the base particle (a
Although it varies depending on the characteristics of the binder resin contained in l, 1.59 x 10" to 1 base particle (a)
9.56X 10-erg, preferably 1.20X1
A mechanical impact force of 0--1.60×10-'erg may be applied.

In the present invention, resin fine particles (bl are base particles (a
It is necessary to treat the surface of the material so that the coverage is 10 to 80%.

When the coverage is in the range of 10 to 80%, the toner has sufficient blocking resistance, offset resistance, and wrapping resistance. However, when the coverage is less than 10%, blocking resistance becomes insufficient and the image deteriorates quickly. On the other hand, when the coverage exceeds 80%, the releasability during fixing becomes insufficient, and the offset resistance and wrapping resistance deteriorate.

The coverage rate of the resin fine particles (b) on the surface of the base particles (a) can be calculated theoretically using the following formula.

ρ Spirit, (100-C) D% ρ1: Specific gravity ρ of base particle (a)! = specific gravity of resin particles (bl) Dl: particle size of base particle (a), : particle size of resin particles (bl) C: concentration of resin particles (bl) An example of a preferred method for producing the toner according to the present invention First, the binder resin material is pulverized and classified to obtain base particles (al) having a particle size desired as a toner.The base particles + al may contain various additives as described above. Then, resin fine particles (b) are added to the base particles (al) and stirred using, for example, a V-type mixer,
As a result, the fine resin particles fbl are electrostatically attached to the surface of the base particles (al), and then they are put into an impact-type pulverizer and subjected to impact.

By treating in this manner, the resin fine particles (b) are fixed to the surfaces of the base particles (al particles).

Note that when additives such as colorants, fixability improvers, magnetic substances, and other property improvers are dispersed and contained in the base particles (a), they must be uniformly mixed in advance using an extruder, etc. After that, it may be crushed and classified to obtain a powder having a desired particle size.

A fluidizing agent may be added and mixed from the outside to the toner obtained as described above. Examples of such fluidizing agents include silica, alumina, titania, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, cerium oxide, antimony trioxide, zirconium oxide, calcium carbonate, silicon carbide, and nitride. Examples include fine particles such as silicon. Particularly preferred are silica particles, and as such silica, commonly known colloidal silica is used, and those that have been subjected to hydrophobization treatment are particularly preferred. Furthermore, in order to positively charge the toner, silica surface-treated with an amino-modified silicon compound is preferable. The mixing ratio of the fluidizing agent is preferably 0.01 to 5% by weight based on the total toner, particularly 0.05% by weight.
~2% by weight is preferred.

The carrier used with the toner of the present invention is not particularly limited, but carriers having an average particle size of 20 to 200 μm, particularly 30 to 150 μm are preferred.

There are no particular restrictions on positively chargeable carriers as long as they have strong positive chargeability, but specific examples include ferromagnetic metals such as iron, nickel, and cobalt, alloys containing these metals, ferrite,
Particles of ferromagnetic metal compounds such as magnetite coated with methyl methacrylate polymer, methyl methacrylate-styrene copolymer, polyvinyl pyridine, etc. may be mentioned.As the negatively chargeable carrier, particularly if it is negatively chargeable or strongly Although there are no restrictions, specifically, particles of ferromagnetic metals such as iron, nickel, and cobalt, alloys containing these metals, and compounds of ferromagnetic metals such as ferrite and magnetite,
Examples include those coated with fluororesins such as vinylidene fluoride-tetrafluoroethylene copolymer, tetrafluoroethylene, 2.2.2-1-lifluoroethyl methacrylate, pentafluoro-n-propyl methacrylate, or silicone resin. It will be done. Particularly preferred is one coated with a fluorinated alkyl (meth)acrylate polymer, and in this case, it is preferred that the content of fluorinated alkyl (meth)acrylate repeating units in this coating layer is greater than 50% by weight.

The toner of the present invention is used to develop an electrostatic latent image formed in, for example, an electrophotographic copying machine, and the obtained toner image is electrostatically transferred onto a recording material and then fixed by a heating roller to form the final image. A copy image can be obtained.

〔Example〕

Hereinafter, the present invention will be described in detail, but the embodiments of the present invention are not limited to these Examples. In addition, in the following, "1 part" represents "part by weight".

<Crystalline polyester 1> Sebacic acid 1500g and hexamethylene glycol 9
64g, capacity 5I with thermometer, stainless steel stirrer, glass nitrogen gas inlet tube and down-flow condenser! This flask was placed in a mantle heater, and nitrogen gas was introduced through a glass nitrogen gas inlet tube to raise the temperature while maintaining an inert atmosphere inside the reactor.

Thereafter, 13.2 g of p-)luenesulfonic acid was added and reacted at a temperature of 150°C. When the amount of water distilled by the esterification reaction reached 250, the reaction was stopped, the reaction system was cooled to room temperature, and a crystalline polyester consisting of polyhexamethylene sebacate having a hydroxyl group at the end of the molecule was obtained. Obtained.

This crystalline polyester I had a melting point Tm of 64° C. and a weight average molecular weight Mw of 14.000.

Crystalline polyester 2> Same as crystalline polyester 1, melting point Tm or 72℃
A crystalline polyester 2 made of polyethylene sebacate having a weight average molecular weight Mw of 12.800 was obtained.

<Amorphous vinyl polymer 1> 100 parts of toluene was placed in a separable flask with a capacity of 11, and 75 parts of styrene, 25 parts of butyl acrylate, and 0.00 parts of benzoyl peroxide were added as monomers for high molecular weight components. After adding 2 parts of the flask and replacing the gas phase in the flask with nitrogen gas, the temperature was raised to 80° C. and maintained at that temperature for 15 hours to carry out the first stage polymerization. In addition, the weight average molecular weight M in the homopolymer of this monomer for high molecular weight components
w is 46], 000, and the glass transition temperature Tg is 61°C.

Thereafter, the inside of the flask was cooled to a temperature of 40°C, and 85 parts of styrene, 10 parts of butyl methacrylate, 5 parts of acrylic acid, and 4 parts of benzoyl peroxide were added as monomers for low molecular weight components. In addition, after continuing stirring at a temperature of 40°C for 2 hours, the temperature was raised again to 80°C and maintained at that temperature for 8 hours to perform second stage polymerization.

Next, add 0 zinc oxide, which is a polyvalent metal compound, to the flask.
．． 5 g was added, and the reaction was carried out for 2 hours while maintaining the temperature at reflux and stirring.

Thereafter, toluene was distilled off using an aspirator and a vacuum pump, and the mixture was dried to obtain an amorphous vinyl polymer 1 in which carboxyl groups of the vinyl polymer were reacted with zinc oxide to form ionic crosslinks.

This amorphous vinyl polymer 1 has two peaks in its molecular weight distribution determined by GPC, with the peak molecular weight on the high molecular weight side being 363.000, and the peak molecular weight on the low molecular weight side being 7.000.
It is 590. In addition, the weight average molecular weight Mw is 165.0
00. The value of Mw/Mn is 25.9, the glass transition temperature T
g was 62°C, and the softening point Tsp was 130°C.

<Amorphous vinyl polymer 2> Capacity] I! Put 100 parts of toluene in a separable flask, add 85 parts of styrene, 10 parts of butyl acrylate, 5 parts of succinic acid monoacryloyloxyethyl ester, and 1 part of benzoyl peroxide. After replacing the gas phase with nitrogen gas, the temperature was 80°C.
The temperature was raised to 0.degree. C., and the temperature was maintained for 5 hours to carry out polymerization.

After that, 4 parts of benzoyl peroxide was further added and the temperature was 8.
Polymerization was continued at 0° C. for 10 hours.

Next, add 0 zinc oxide, which is a polyvalent metal compound, to the flask.
．． 5 g was added, and the reaction was carried out for 2 hours while maintaining the temperature at reflux and stirring.

Thereafter, toluene was distilled off using an aspirator and a vacuum pump to obtain an amorphous vinyl polymer 2 in which zinc oxide reacted with the carboxyl groups of the vinyl polymer to form ionic crosslinks.

This amorphous vinyl polymer 2 has one peak in the molecular weight distribution by GPC, and the weight average molecular weight Mw is 8.
3.000, the value of Mw/Mn was 7.5, the glass transition temperature Tg was 67°C, and the softening point Tsp was 127°C.

<Copolymer A> 15 parts of the crystalline polyester 1, 85 parts of the amorphous vinyl polymer 1, and 0.0 parts of p-toluenesulfonic acid.
5 parts and 100 parts of xylene were placed in a separable flask with a capacity of 31 and refluxed at a temperature of 150°C for 1 hour, and then the xylene was distilled off using an aspirator and a vacuum pump to form a crystalline polyester with no ionic crosslinking. A copolymer A consisting of a graft copolymer with a regular vinyl polymer was obtained.

<Copolymer B-D> In the production of copolymer A, the crystalline polyester and the amorphous vinyl polymer were prepared in the same manner except that the crystalline polyester and the amorphous vinyl polymer were changed as shown in Table 1 below. Each copolymer B- consisting of a graft copolymer with a polymer
I got a D.

Resin fine particles 1> After charging 150 parts of deionized water into a round bottom flask with a capacity of If equipped with a stirrer and a cooler, set it on a mantle heater and introduce nitrogen gas from a glass nitrogen gas introduction tube to start the reaction. Raise the temperature to 80℃ while keeping the inside of the vessel in an inert atmosphere.
I kept it.

To this are added 70 parts of styrene, 20 parts of methyl methacrylate, 10 parts of n-butyl acrylate, and 50 parts of deionized water.
An initiator aqueous solution consisting of 6 parts of potassium persulfate, 6 parts of sodium thiosulfate, and 50 parts of deionized water was added dropwise over 1 hour, and stirring was continued for another 1 hour. After that, the temperature was reset to 60° C. and stirring was continued for another hour to obtain fine resin particles 1 having a non-volatile content of 40.5% and an average particle diameter of 400 nm. This resin fine particle l
The glass transition temperature Tg is 82℃ 1 weight average molecular weight Mw is 15.500, the value of Mw/Mn is 7.5, the softening point Tsp
was 125°C.

Ta.

<Resin fine particles 2> In resin fine particles 1, the monomer mixture was added to styrene 8
3 parts of n-butyl acrylate H, 1 part of sodium alkylbenzenesulfonate, and 50 parts of deionized water, and the aqueous initiator solution was changed to 3 parts of polyoxyethylene nonylphenol and nitric acid The procedure was the same as that for resin fine particles 1, except that the initiator aqueous solution was changed to consist of 3 parts of cerium ammonium and 50 parts of deionized water.
Resin fine particles 2 with a non-volatile content of 37% and an average particle diameter of charcoal particles of 70 parts m were obtained. The glass transition temperature T of this resin fine particle 2
g is 56°C, weight average molecular weight Mw is 92.000, Mw
/Mn value was 32, and softening point Tsp was 135°C.

<Comparative Resin Fine Particles 1> Comparative Resin Fine Particles 1 having an average particle size of -charcoal particles of 550 parts m were obtained in the same manner as in Resin Fine Particles 1 except that the stirring conditions were changed. The molecular weight distribution of this comparative resin fine particle l,
The softening point and glass transition temperature were almost the same as those of resin fine particles 1.

Comparative Resin Fine Particles 2> In Resin Fine Particles 1, the monomer mixture was added to Methyl 150
Comparative resin fine particles 2 having an average particle diameter of 400 parts (m), which is the average particle size of the charcoal particles, were obtained in the same manner except that the monomer mixture was changed to a monomer mixture consisting of 23 parts of methyl methacrylate, and 27 parts of n-butyl acrylate. The comparative fine resin particles 2 had a glass transition temperature Tg of 47°C, a value of Mw/Mn of 8.2, and a softening point Tsp of 05°C.

Comparative Resin Fine Particles 3> In resin fine particles 1, the initiator aqueous solution was mixed with 3 parts of potassium persulfate, 3 parts of sodium thiosulfate, and 50 parts of deionized water.
Comparative resin fine particles 3 having a softening point Tsp of 165° C. were obtained in the same manner except that the aqueous initiator solution was changed from

The value of Mw/Mn, average particle size, and glass transition temperature of the comparative fine resin particles 3 were almost the same as those of the fine resin particles 1.

<Comparative Resin Fine Particles 4> Comparative Resin Fine Particles 4 having an Mw/Mn value of 4.0 were obtained in the same manner as in Resin Fine Particles 1 except that the polymerization was carried out at a fixed system temperature of 80°C. The average particle diameter I) io and glass transition temperature Tg of the comparative fine resin particles 4 were the same as those of the fine resin particles 1, and the softening point Tsp was 110°C.

Comparative Resin Fine Particles 5> Comparative Resin Fine Particles 5 of 25r+m were obtained in the same manner as Resin Fine Particles 2 except that the stirring conditions were changed.

The value of Mw/Mn and the softening point Tsp of this comparative resin fine particle 5
The glass transition temperature Tg was almost the same as that of Resin Fine Particles 2.

<Comparative resin fine particles 6> In resin fine particles 1, the monomer mixture was mixed with styrene 8
0 parts, 10 parts of methyl methacrylate, and 10 parts of n-butyl acrylate,
The same procedure was repeated except that the aqueous initiator solution was changed to an aqueous initiator solution consisting of 8 parts of potassium persulfate, 8 parts of sodium thiosulfate, and 50 parts of deionized water. 400 parts m of Comparative Resin Fine Particles 6 were obtained. The comparative fine resin particles 6 had a softening point Tsp of 98°C, a glass transition temperature Tg of 51°C, and a value of 6.8 for Mw/Mn.

<Examples 1 to 4. Comparative Example 1-10> In each Example and Comparative Example, 100 parts of the copolymer shown in Table 1 below and carbon black r Mogul LJ
(manufactured by Cabot) and 10 parts of paraffin wax.
3 parts of Sasol Wax 5 PRAY 40 J (manufactured by Sasol Marketing) and 3 parts of alkylene bis fatty acid amide Hoechst Wax CJ (manufactured by Hoechst)
After melting and kneading with heated rolls, cooling, coarsely pulverizing, finely pulverizing with a supersonic jet mill, and classifying with an air classifier, the average particle size was 11.0 μm.
The base particles were obtained.

These base particles and fine resin particles of the types and proportions shown in Table 1 below were mixed using a V-type mixer to adhere the fine resin particles to the surface of the base particles.

Next, this was transferred to the Nara Hybridization System NHS-IJ (Nara Machine Manufacturing Co., Ltd.) and processed for 5 minutes at the rotational speed of the impact blades at 600 rpm to fix the resin fine particles on the surface of the base particles, thereby forming each toner. I got it.

When the surface of each toner was observed using a scanning electron microscope, it was confirmed that the resin fine particles were firmly fixed to the surface of the base particles.

For each toner, the coverage ratio by resin particles was calculated based on the theoretical formula described above, and the results shown in Table 1 below were obtained.

<Preparation of developer> 100 parts of each of the above toners, 5 parts of a toner mixture obtained by mixing 0.8 parts of nitrogen-containing silica and part O, OS of zinc stearate in a V-type mixer, and fluorinated Each two-component developer was prepared by mixing 95 parts of a carrier obtained by coating an alkyl methacrylate polymer on a ferrite core material having an average particle size of 80 μm at a concentration of 2% by weight.

Each developer thus obtained was evaluated as follows.

Evaluation> (1) Evaluation of fixing performance Equipped with a latent image carrier made of an organic photoconductive semiconductor, a developing device for two-component developer, and a heating roller fixing device, modified to allow variable adjustment of the temperature setting of the heating roller. Using a modified electrophotographic copying machine rU-Bix 1550MRJ (manufactured by Nika), the linear speed of the heating roller was set to 139 mm/sec, and the temperature of the pressure roller was kept lower than the set temperature of the heating roller. Then, set the temperature of the heating roller to 100-2.
A photocopying test was carried out in which a fixed toner image was formed using each of the above developers while changing the temperature in stages within the range of 40"C, and a constant load was applied to the edges of the obtained fixed toner image using a rubbing tester. After rubbing it, measure the residual rate of the image at the edge with a microdensitometer and find that the residual rate is 8.
The lowest set temperature (minimum fixing temperature) exhibiting 0% or more was determined.

The heating roller fixing device has a heating roller with a diameter of 30 mm and whose surface layer is made of PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer).
Surface layer coated with PFA +) J-:/rubber rK
E-130ORTV" (manufactured by Shin-Etsu Chemical Co., Ltd.) and a pressure roller with a linear pressure of 0.8 kg/cm.
The nip width was 4.3 mm, and no mechanism for applying a release agent such as silicone oil was provided.

(2) Evaluation of single-wrap property Using a so-called solid black original, a live copying test was conducted in the same manner as in the above evaluation of fixing property, while the set temperature of the heating roller was gradually lowered. The highest temperature (coiling generation temperature) at the time of heating was determined. However, "No" in Table 2 indicates that no wrapping occurred.

(3) Evaluation of anti-offset property A fixed toner image was formed in the same manner as in the evaluation of fixing performance above, except that the pressure roller was kept at a temperature close to the set temperature of the heating roller, and immediately after that, a blank recording material was was sent to the heating roller fuser under similar conditions and visually observed whether or not toner stains were generated on the heated roller at each set temperature of the heating roller. (Offset generation temperature) was determined.

(4) Evaluation of fluidity Taking advantage of the fact that powder with high fluidity has a low degree of compaction,
Each toner was loosely filled from above into a container with a diameter of 28 mm and a volume of 100 m1, and its weight was measured to determine the static bulk density of the toner. The evaluation is: "○J" for static bulk density of 0.28 g/ml or more, "△" for 0.21 to 0.27 g/ml, 0,
Less than 20 g and 7 ml was rated "x".

(5) Evaluation of anti-blocking property 2g of each toner was placed in a sample tube, tapped 500 times with a tap denser, and the temperature was 55°C, relative humidity 2.
The mixture was left in a 6% atmosphere for 2 hours, and then separated using a 48-mesh sieve, and the proportion of aggregates remaining on the sieve, that is, the aggregation rate, was measured.

(6) Evaluation of durability Using each of the above developers, the electrophotographic copying machine "U-Bix"
1550MRJ (:l=force atJ) Modified machine i:
The linear velocity of the heating roller was 139 mm/sec, the temperature of the heating roller was set to the minimum fixing temperature of each toner, and the process was repeated 60,000 times under normal temperature and normal humidity environmental conditions (temperature 20°C, relative humidity 60%). The image density (Dm
Durability was evaluated in terms of ax) and fog.

The above results are shown in Table 2.

As is clear from Table 2, the toner of the present invention has excellent blocking resistance, low-temperature fixing properties, offset resistance, and high durability.

[Effects of the Invention] As explained in detail above, the toner for developing electrostatic images of the present invention has excellent low-temperature fixing properties, anti-blocking properties, and release properties during fixing, as well as stable image quality. This image can be repeatedly formed many times.

Specifically, it is chemically bonded to crystalline polyester or amorphous vinyl polymer in the form of a graft or block, and the glass transition temperature Tg is specified to be 60°C or less, so the crystalline component is low. Combined with the effect of melt viscosity, fixing properties are significantly improved.

On the other hand, the average particle diameter Dso, the glass transition temperature Tg, the ratio Mw/
Since the vinyl resin fine particles (fb), which have unique characteristics that define the Mn value and the softening point Tsp, are fixed to the surface of the base particle +a+, adhesion (fusion) of the particles to each other is prevented and blocking resistance is achieved. In addition, even when used repeatedly, filming on the photoreceptor and developing sleeve is reduced and good image quality is maintained, and the resin fine particles fbl interact with the amorphous components of the base particles [a] during fixing. Since it melts and an entanglement effect appears, the excellent fixing properties, anti-offset properties, and mold release properties of the base particles (a+) are expressed as they are.

−′, Agent: Masahiko Oi, Patent Attorney 1115. Q-)
ゝ

Claims (1)

[Scope of Claims] (1) Base particles containing as a binder a graft or block copolymer of a crystalline polyester and an amorphous vinyl polymer whose glass transition temperature is 60°C or less ( On the surface of a), the average particle size D_5_0,
Vinyl resin fine particles (b) whose glass transition temperature Tg, the ratio Mw/Mn of weight average molecular weight Mw to number average molecular weight Mn, and softening point Tsp satisfy the following formula are fixed by mechanical impact force, and the coating is Toner for electrostatic image development characterized by having a ratio of 10 to 80% 30 nm≦D_5_0≦50
0nm Tg≧50℃ 5.0≦Mw/Mn≦40 100℃≦Tsp≦160℃