JPH08227174A - Electrophotographic toner - Google Patents

Abstract

PURPOSE: To obtain a toner using a styrene-acrylic copolymer contg. >=50% styrene as a bonding resin, having stable electrostatic chargeability and giving a satisfactory image free from the blurring of letters and fog. CONSTITUTION: In this toner contg. a bonding resin, a colorant and an electric charge controlling agent, the bonding resin is a styrene-acrylic copolymer contg. >=50% styrene and having at least one peak in the mol.wt. region of 1×10<3> -5×10<5> its mol.wt. distribution measured by gel permeation chromatography and the electric charge controlling agent is a compd. having 100-200 deg.C m.p.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

[0002]

2. Description of the Related Art The electrophotographic method conventionally used in the image forming method of a copying machine is generally applied to a photosensitive member having a photosensitive layer made of a photoconductive material. After the electrostatic charge is applied, an electrostatic latent image corresponding to the original is formed on the surface of the photoconductor by image exposure, and the electrostatic latent image is developed with a developer to form a toner image. Is transferred to a recording material such as paper and then fixed.

A developer for developing the above-mentioned electrostatic latent image is required to have many functions in terms of developability and fixability, and these functions are, for example, electrostatic and thermal properties of toner. And physical properties, chemical characteristics, or powder characteristics related to fluidity, blocking, particle size distribution, etc. are problems. In response to these, the material, shape, and forming method of the toner particles have been studied, and further various additives for complementing the characteristics have been studied.

Inorganic photoconductors such as selenium, zinc oxide, and cadmium sulfide, organic photoconductors, and the like are known as photoconductors used in electrophotography. In recent years, however, the production cost is low and the sensitivity is high. Therefore, organic photoreceptors made of organic semiconductors, which have advantages such as durability, heat resistance, and no toxicity to human bodies, and which have good film forming properties, have been used.

When an organic photoreceptor is used, a negative electrostatic latent image is generally used.

The binder resin, which is a constituent component of the toner, occupies most of the toner and therefore has a great influence on the toner characteristics, and many studies have been made. At present, the use of polyester resins and styrene-acrylic copolymers as the binder resin has become the mainstream. Styrene-acrylic resin is advantageous in terms of cost, but styrene-acrylic copolymer is known to be negatively charged with styrene component and positively charged with acrylic component in frictional charging with a general carrier. There is.

Therefore, when controlling the charging property of the toner,
The influence of the composition of each component is often observed, and when a so-called positively chargeable toner is to be obtained, the presence of the styrene component adversely affects the chargeability.

Further, a method of using a charge control agent to control the chargeability is known. These charge control agents are added to the inside of the toner and used as a material for controlling the chargeability of the toner.

Attempts have also been made to control the chargeability by exposing the charge control agent particles contained in the toner surface (JP-A-62-206541, JP-A-63-301964, JP-A-64-6876).
4, gazette 63-244056 gazette, gazette 63-318570 gazette,
63-131148, 62-246043, 63-2075.
Issue). Attempts to control the chargeability by exposing the charge control agent particles contained in these toner surfaces, the charge control agent is present and exposed on the toner surface, so that the triboelectric chargeability is reliably controlled. Since the charge control agent is present only on the surface, the stability becomes insufficient.

In order to satisfy both the control and the stability of the charging property, Japanese Patent Laid-Open No. 4-21862 discloses that a charge control agent is present on the surface and inside of the toner, and the charge control is present on the surface and inside. It is proposed to control the amount of agent.

However, in the above technique, styrene-
When a positively chargeable component and a negatively chargeable component coexist, such as an acrylic copolymer, a stable positively chargeable toner can be obtained by only allowing the charge control agent to exist on the toner surface and inside and specifying the amount. It was difficult to get. In particular, when a styrene-acrylic resin having a styrene content of more than 50% is used, it is difficult to obtain a stable positively chargeable toner, and there is a problem that characters such as letters and fogging occur in a copied image. .

[0012]

Accordingly, an object of the present invention is to provide a styrene-acryl copolymer containing 50% or more of a styrene-based component in a binder resin, which shows a stable chargeability and gives a good image free from dust and fog. An object is to provide an electrophotographic toner using a polymer.

[0013]

The above objects of the present invention are: (1) In a toner containing at least a binder resin, a colorant, and a charge control agent, the binder resin is measured by gel permeation chromatography (GPC). In the above-mentioned molecular weight distribution, it is a styrene-acrylic copolymer having at least one peak in a region having a molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁵ , and containing 50% or more of a styrene-based component. A toner, wherein the agent is a compound having a melting point of 100 to 200 ° C. (2) The toner according to (1) above, wherein the melting point of the charge control agent is in the range of 120 to 200 ° C. (3) The toner according to (1) or (2) above, wherein the charge control agent is a compound having a quaternary ammonium salt structure. (4) The toner according to (3) above, wherein the compound having a quaternary ammonium salt structure is a compound represented by the following general formula.

[0014]

Embedded image [Wherein R ^{1 to} R ⁴ are substituted or unsubstituted C ^{1 to} C 18
Represents an alkyl group or a substituted or unsubstituted benzyl group, and A ⁻ represents an anion. However, at least one of R ^{1 to} R ⁴ is an alkyl group having 8 to 18 carbon atoms. ] Is achieved.

By using a compound having a melting point of 100 to 200 ° C. as the charge control agent, a stable positive charge can be obtained in a toner using a styrene-acrylic copolymer containing 50% or more of a styrene-based component as a binder resin. The reason why the sex is obtained is not clear at present, but the inventors speculate as follows.

The charge control agent exhibits a triboelectric charging function when it is present on the surface, and the effect of the charge control agent cannot be sufficiently exhibited only by dispersing it in the resin. In the case of a toner using a resin containing a large amount of styrene-based components as the binder resin, as described above, the triboelectrification property is biased toward the negative charging property. However, if the charge control agent is present on the surface, the charge stability will be insufficient.

Usually, when kneading and crushing to form a powder, in the crushing process, the particles are crushed by colliding with each other or colliding with a collision plate, but in this case, microscopically. However, heat is generated. 100-200 ℃ as a charge control agent
When a compound having a melting point of is used, the charge control agent having a low melting point is oriented on the surface of the toner particles due to the heat generated microscopically at the time of pulverization, and many styrene-based components having a negatively chargeable surface are used. Even with the existing resin, the positive charging property can be obtained, and the positive charging property can be stably obtained.

The present invention will be described in detail below.

The styrene-acrylic copolymer used in the present invention is a styrene-acrylic copolymer having a styrene component content of 50% or more. The content of the styrene-based component as used herein means the ratio (% by weight) of the charged amount of the styrene-based component monomer to all the monomers at the time of copolymer synthesis.

In the present invention, it is necessary that the styrene-acryl copolymer has a styrene-based component content of 50% or more, and particularly when the styrene-based content is less than 50%. No significant effect can be achieved. The reason for this is that the negative chargeability is low due to the low content of the styrene-based component, and as a result, it is not necessary to use the charge control agent of the present invention.

The styrene-acrylic copolymer is a styrene-based component containing styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethyl styrene, pt-butyl styrene, pn-
Hexyl styrene, pn-octyl styrene, pn
-Nonylstyrene, pn-decylstyrene, pn-
Styrene or styrene derivative such as dodecyl styrene is used as an acrylic component, methyl methacrylate,
Ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate,
Methacrylic acid ester derivatives such as lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylic monomers such as acrylic acid ester derivatives such as isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate And can be obtained by copolymerization according to a conventional method. These monomers can be used alone or in combination. Moreover, other copolymerization components can be copolymerized with these styrene-acrylic copolymers.

Styrene is most preferred as the styrene component in the styrene-acrylic copolymer. Further, when the content of the styrene-based component is 60% or more, the effect of the present invention is markedly exerted, which is particularly preferable.

The styrene-acrylic copolymer of the present invention is
At least in the molecular weight distribution measured by gel permeation chromatography (GPC), it has a molecular weight distribution having at least one peak in a region having a molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁵ . By having the above-mentioned molecular weight distribution, a low molecular weight component is contained, the solubility of the charge control agent is increased by the low molecular weight component, and the charge control agent is easily oriented on the toner surface during pulverization, This is because the effects of the present invention can be exerted more. The peak in the molecular weight distribution is particularly preferably in the region where the molecular weight is 2 × 10 ^{3 to} 3 × 10 ⁴ .

The measurement of the molecular weight by GPC is carried out at a temperature of 40 ° C. by flowing tetrahydrofuran at a flow rate of 1.2 ml / min and injecting 3 mg of a sample solution of tetrahydrofuran having a concentration of 0.2 g / 20 ml as a sample weight. In measuring the molecular weight of a sample, the measurement conditions are selected so that the logarithm of the molecular weight and the number of counts of the calibration curve made by monodisperse polystyrene of several kinds of the sample have a linear range. The peak molecular weight is calculated from the obtained GPC chromatogram count number using the calibration curve.

The molecular weight distribution of the resin is such that the molecular weight is from 1 × 10 ³ to
Other components are not particularly limited as long as they have at least one peak in the region of 5 × 10 ⁵ , but it is also preferable to contain a high molecular weight component. In this case, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the resin as a whole is preferably about 4 to 60, and particularly preferably this ratio is about 8 to 50. .

The method of synthesizing the resin is not particularly limited. Any of the so-called suspension polymerization method, solution polymerization method, bulk polymerization method and emulsion polymerization method may be used. These may be used in combination.

The charge control agent of the present invention has a melting point of 100 to 200 ° C.
If any charge control agent can be used,
Those having a melting point in the range of 120 to 200 ° C are preferable. Also,
The charge control agent is preferably a compound having a quaternary ammonium salt structure, more preferably a compound represented by the following general formula.

[0028]

Embedded image [Wherein R ^{1 to} R ⁴ are substituted or unsubstituted C ^{1 to} C 18
Represents an alkyl group or a substituted or unsubstituted benzyl group, and A ⁻ represents an anion. However, at least one of R ^{1 to} R ⁴ is an alkyl group having 8 to 18 carbon atoms. Specific examples of the charge control agent used in the present invention include the following.

[0029]

[Chemical 4]

[0030]

Embedded image The colorant used in the toner of the present invention is not particularly limited,
Various conventionally known materials can be used. As the colorant used in the toner of the present invention, for example, carbon black, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue,
Examples include DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Malachite Green Oxalate and Rose Bengal.

Various additives such as a release agent can be added to the toner of the present invention. Examples of the release agent used in the toner of the present invention include low molecular weight polypropylene, low molecular weight polyethylene, polyolefins such as low molecular weight ethylene-propylene copolymer, microcrystalline wax, carnauba wax, sazol wax, paraffin wax, etc. Waxes and the like can be mentioned. As low molecular weight polypropylene, etc., number average molecular weight 1500 ~
Those having a molecular weight in the range of 10,000 are preferred. The number average molecular weight is a value measured by high temperature gel permeation chromatography and calculated in terms of polystyrene. It is preferable to add 1 to 5% by weight of these release agents to the toner.

The toner of the present invention is preferably produced by mixing toner constituent components, melt-kneading, pulverizing and classifying. In this pulverizing step, the charge control agent can be oriented on the toner surface.

The pulverizing method includes a jet pulverizing method utilizing a jet stream and a mechanical pulverizing method utilizing a rotating body. In producing the toner of the present invention,
Mechanical grinding methods are more suitable. This is because in the jet crushing method, the particles are crushed by the collision of the particles, and in the mechanical crushing method, the particles are crushed by the collision of the particles with the rotating body. This is because the heat generation during pulverization is larger and the charge control agent is more likely to melt when the mechanical pulverization method is used.

Inorganic fine particles may be added to the coloring particles in the toner of the present invention from the viewpoint of imparting fluidity.
As the inorganic fine particles, inorganic oxide particles such as silica, titania and alumina are preferable, and these inorganic fine particles may be hydrophobized with a silane coupling agent, a titanium coupling agent or the like.

The toner of the present invention can be used as either a two-component developer or a magnetic one-component developer.

When used as a two-component developer, the carrier is an uncoated carrier composed only of magnetic material particles such as iron or ferrite, a resin-coated carrier in which the surface of magnetic material particles is coated with a resin, or a resin. Any of the resin dispersion type carriers obtained by mixing the above and magnetic powder may be used. The volume average particle diameter of the carrier is preferably 30 to 150 μm.

When used as a magnetic one-component developer,
It is preferable that a ferromagnetic material such as magnetite having a number average primary particle diameter of 0.1 to 2.0 μm is contained as a colorant. In this case, the magnetic substance is added to the toner in an amount of 20 to 60% by weight.

Further, in the present invention, a non-magnetic one-component toner composed of only non-magnetic toner can be used without using a carrier.

As a fixing method suitable for fixing the toner of the present invention, a heat roll fixing method is used, or a heating member fixedly installed is provided on the heating member so as to face the heating member by a pressing member. Examples thereof include a film fixing method in which a film material moving in contact with the body is pressed and heat-fixed.

The former hot roll fixing system is composed of iron, aluminum or the like whose surface is coated with a material having excellent releasability such as polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer. In this method, the toner image is heated and fixed by passing the toner image between the upper roller provided with a heat source inside the metal cylinder and the lower roller formed of silicone rubber so that the toner image is in contact with the upper roller.

A linear heater is used as a heat source for the upper roller, and the surface temperature of the upper roller is heated to about 120 to 200 ° C. Upon fixing, pressure is applied between the upper roller and the lower roller to deform the lower roller and form a so-called nip. The formed nip width is preferably 1 mm to 10 mm, more preferably 1.5 mm to 7 mm. When the nip width is narrow, heat cannot be uniformly applied to the toner, and uneven fixing tends to occur. When the nip width is wide, melting of the resin is promoted and fixing offset becomes excessive. Cause a problem. For fixing, transfer material is 40 mm / sec.
It is preferable to move at a speed of 400 mm / sec.

A mechanism for preventing toner from adhering and a mechanism for cleaning the adhered toner can be added to the fixing device. As these mechanisms, silicone oil such as polydimethylsiloxane, polyphenylmethylsiloxane and fluorine-based silicone oil is supplied to the upper roller, and silicone oil such as polydimethylsiloxane, polyphenylmethylsiloxane and fluorine-based silicone oil is impregnated. A mechanism for cleaning the upper roller with a pad, a roller, a web, etc. may be mentioned.

1 and 2 illustrate the latter film fixing system. FIG. 1 is an explanatory view of a film fixing system using an endless fixing film, and FIG. 2 uses an endless fixing film. It is explanatory drawing of the film fixing system which was used.

In FIGS. 1 and 2, A is a linear heating element, 21 is a driving roller, 22 is a driven roller, 23 is a pressure roller, 24 is an endless fixing film, 25 is an alumina substrate, 26 is an electric resistor, 27 is a temperature sensor, 31 is a driven roller, 32 is a driving roller, and 34 is an end fixing film.

In FIG. 1, the endless fixing film 2
4 is driven in the direction of arrow 28 by a drive roller 21 and a driven roller 22. The linear heating element A used for fixing is composed of an alumina substrate 25 and an electric resistor 26, and the linear heating element A includes an electric resistor 2
A temperature sensor 27 is provided in contact with the electric resistor 26 in order to detect the heating temperature by 6. In the linear heating element A , the electric resistor 26 has an endless fixing film 2
It is arranged so as to contact with 4. Further, a pressure roller 23 is installed below the linear heating element A in contact with the endless fixing film 24, and is rotating in a direction indicated by an arrow.

The developed support is sent in the direction of arrow 29, and the toner image on the support is heated and fixed by the line-shaped heating member A through the endless fixing film 24.

FIG. 2 shows a film fixing system using an end fixing film instead of the endless fixing film 24 shown in FIG. 1. The end fixing film 34 wound around the driven roller 31 is , Drive roller 32
And is driven in the direction of arrow 38. The line-shaped heating element A and the pressure roller 23 used for fixing are configured in the same manner as in FIG. 1, and the developed support is sent in the direction of arrow 29, and the toner image on the support is It is heated and fixed by the line-shaped heating body A through the fixing film 24.

As the linear heating element A , a linear heating element having a low heat capacity is used. The low heating capacity linear heating element has a thickness of 0.2 mm to 5.0 mm, preferably 0.5 mm to 3.5 m.
m, width 10mm ~ 15mm, longitudinal length 240mm ~ 400mm alumina substrate 1.0mm ~ 2.5mm width applied to form an electrical resistor, electrical resistance is formed from both ends of the electrical resistor To be heated. 100 V for heating power supply, cycle 2
A pulse of 5 msec. Is used, and the amount of energy released is changed by changing the pulse width to control the heating temperature.

In the linear heating element, when the surface temperature of the electric resistor detected by the temperature sensor is T ₁ , the surface temperature T ₂ of the fixing film material moving on the electric resistor is lower than T _1. Become. The surface temperature T ₁ of the electric resistor is preferably 120 ° C. to 220 ° C., and the surface temperature T ₂ of the fixing film material in contact with the electric resistor is 0.5 ° C. to 10 ° C. from the temperature of T _1.
It is preferably low. Further, the surface temperature T ₃ of the fixing film material at the position where the fixing film material is separated from the surface of the fixed toner is preferably almost equal to T ₂ .

The fixing film material has a thickness of 10 μm to 3 μm.
A heat-resistant film of 5 μm, for example, a film made of polyester, polyperfluoroalkoxy vinyl ether, polyimide, or polyetherimide, and a release material layer obtained by adding a conductive material to a fluororesin such as Teflon is coated in a thickness of 5 μm to 15 μm. . The total thickness of the fixing film is generally 10 μm to 100 μm. The fixing film is driven by a driving roller and tensioned so that the fixing film is conveyed without wrinkles and twists.

As the pressure roller, a roller having a rubber elastic layer having a high releasability such as silicone rubber is used. The transfer material having a toner image is passed through so that the toner image side is in contact with the endless film, is pressed by a pressure roller, and is heated and fixed by the heating body through the endless fixing film. Pressurization by the pressure roller,
Generally, the total pressure is 2 kg to 30 kg. Transfer material is 40mm / se
It is preferable to move at a speed of c. to 400 mm / sec.

Further, instead of the endless fixing film, a simple fixing film having no supporting roller such as a driving roller therein may be used.

The fixing device can be provided with a mechanism for preventing the toner from adhering to the fixing film and a mechanism for cleaning the adhered toner. These mechanisms include supplying polydimethylsiloxane, polyphenylmethylsiloxane, silicone oil such as fluorosilicone oil to the fixing film, impregnating silicone oil such as polydimethylsiloxane, polyphenylmethylsiloxane, fluorosilicone oil, or the like. A mechanism for cleaning the fixing film with the attached pad, roller, web, etc. may be mentioned.

The cleaner 18 shown in FIG. 1 is a cleaning mechanism for the toner adhering to the fixing film and is rotating in the direction shown by the arrow to remove the toner adhering to the endless fixing film 24. Further, the cleaner 18 may rotate in a direction opposite to the direction indicated by the arrow.

[0055]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example << Production of Resins 1 to 6 and Comparative Resins 1 and 2 >>-Production of Resin 1-70 parts of styrene (St), butyl acrylate (BA) 30
And 0.4 part of benzoyl peroxide were reacted at 75 ° C. for 6 hours by a suspension polymerization method. Then, 100 parts of styrene (St) and 0.4 parts of benzoyl peroxide were added to the obtained polymer.
Was added thereto, and the mixture was reacted in a xylene solvent at 80 ° C. for 6 hours in a nitrogen stream, and then desolvated to obtain Resin 1. -Production of Resin 2- 75 parts of styrene (St) and 25 parts of 2-ethylhexyl acrylate (2EHA) were reacted with nitrogen in a bulk polymerization method at 130 ° C for 5 hours. Next, 55 parts of styrene (St), 45 parts of butyl methacrylate (BMA) and 0.4 part of benzoyl peroxide were added to the obtained polymer, and the mixture was reacted in a xylene solvent at 80 ° C. for 7 hours under a nitrogen stream, and then, Then, the solvent was removed to obtain Resin 2. -Production of Resin 3-Styrene (St) 70 parts, Butyl acrylate (BA) 30
And 0.3 part of benzoyl peroxide were reacted at 80 ° C. for 6 hours by a suspension polymerization method. Then, 100 parts of styrene (St) and 0.4 parts of benzoyl peroxide were added to the obtained polymer.
And 6 parts were added and reacted in a xylene solvent at 80 ° C. for 6 hours in a nitrogen stream, and then the solvent was removed to obtain a resin 3. -Production of Resin 4- 72 parts of styrene (St) and 28 parts of 2-ethylhexyl acrylate (2EHA) were reacted with nitrogen in a bulk polymerization method at 130 ° C for 5 hours in a vessel substituted with nitrogen. Next, 68 parts of styrene (St), 32 parts of butyl methacrylate (BMA) and 0.4 part of benzoyl peroxide were added to the obtained polymer, and the mixture was reacted in a xylene solvent at 80 ° C. for 7 hours under a nitrogen stream, and then, Then, the solvent was removed to obtain Resin 4. -Production of Resin 5- 60 parts of styrene (St), methyl methacrylate (MM
A) 40 parts, butyl acrylate (BA) 50 parts, and benzoyl peroxide 0.3 parts were reacted at 75 ° C. for 6 hours by a suspension polymerization method. Then, styrene (S
t) Add 50 parts and benzoyl peroxide 0.4 parts,
React in a xylene solvent under a nitrogen stream at 75 ° C for 8 hours,
Next, the solvent was removed to obtain Resin 5. -Production of Resin 6- 85 parts of styrene (St) and 30 parts of 2-ethylhexyl acrylate (2EHA) were reacted with nitrogen in a bulk polymerization method at 135 ° C for 5 hours, and then the obtained polymer was obtained. 75 parts of styrene (St), 10 parts of methylmethacrylate (MMA), and 0.4 parts of benzoyl peroxide are added to the mixture, and the mixture is reacted in a xylene solvent at 85 ° C. for 5 hours under a nitrogen stream, and then desolvated to give resin 6 Got -Manufacture of Resin 1 for Comparison- 20 parts of styrene (St) and 25 parts of 2-ethylhexyl acrylate (2EHA) were reacted with each other at 130 ° C for 5 hours by a bulk polymerization method in a container in which nitrogen was substituted. Next, 110 parts of styrene (St), 45 parts of butyl methacrylate (BMA) and 0.7 part of benzoyl peroxide were added to the obtained polymer, and the mixture was reacted in a xylene solvent at 80 ° C. for 7 hours under a nitrogen stream, and then, Then, the solvent was removed to obtain Comparative Resin 1. -Production of Comparative Resin 2-Styrene (St) 90 parts, Butyl acrylate (BA) 30
And 0.2 part of benzoyl peroxide were reacted at 75 ° C. for 12 hours by a suspension polymerization method. Then, 80 parts of styrene (St) and 0.4 parts of benzoyl peroxide were added to the obtained polymer.
Was added thereto and reacted in a xylene solvent at 80 ° C. for 7 hours in a nitrogen stream, and then the solvent was removed to obtain Comparative Resin 2.

Table 1 below shows a list of resins 1 to 6 and comparative resins 1 and 2 produced as described above.

[0057]

[Table 1] Further, the molecular weight distributions of the above resins 1 to 6 and comparative resins 1 to 3 are measured under the conditions shown below to obtain the peak molecular weight, and the weight average molecular weight (Mw) / number average molecular weight (Mn) is calculated. did. Device: Tosoh HLC-8020 Column: GMHXL 2 pieces, G2000HXL 1 piece Detector: RI Eluent flow rate: 1.2 ml / min Sample concentration: 0.2 g / 20 ml Sample amount: 3 mg as sample weight Calibration curve: Standard polystyrene Table 2 shows the peak molecular weight and weight average molecular weight (Mw) / number average molecular weight (Mn) of Resins 1 to 6 and Comparative Resins 1 to 3.

[0058]

[Table 2] << Toner Preparation >><Two-ComponentToner> 100 parts of resin shown in Table 3, 3 parts of low molecular weight polypropylene (release agent), 8 parts of carbon black and the charge control agent shown in Table 3 were added, and after premixing, melting, The mixture was kneaded, pulverized by an airflow pulverizer, and classified to obtain colored particles having a volume average particle diameter of 8.5 μm. Next, 0.9 parts by weight of hydrophobic silica was externally added and mixed with 100 parts of the colored particles to obtain toners 1 to 6 as two-component toners and comparative toners 1 to 3.

[0059]

[Table 3] In addition, in the charge control agent, Exemplified Compound 1, Exemplified Compound 3, Exemplified Compound 4, Exemplified Compound 5, Exemplified Compound 7, Exemplified Compound 9 are Exemplified Compound 1, Exemplified Compound 3, Exemplified Compound 4, Exemplified Compound 5, Exemplified Compound 7 and Exemplified Compound 9, and the comparative compounds are shown below.

[0060]

[Chemical 6] <Magnetic One-Component Toner> 100 parts of resin shown in Table 4, 3 parts of low molecular weight polypropylene (release agent), 55 parts of magnetic powder (number average primary particle diameter = 0.2 μm) and charge control agent shown in Table 4 are added. After premixing, melting and kneading were performed, and the mixture was pulverized by an air flow type pulverizer and classified to obtain magnetic colored particles having a volume average particle diameter of 8.4 μm. Next, 0.9 parts by weight of hydrophobic silica was externally added and mixed with 100 parts of the colored particles to obtain magnetic toners 1 to 6 as magnetic one-component toners and magnetic toners 1 to 3 for comparison.

[0061]

[Table 4] In the charge control agent, Exemplified Compound 1, Exemplified Compound 2, Exemplified Compound 4, Exemplified Compound 5, Exemplified Compound 7, Exemplified Compound 9 are Exemplified Compound 1, Exemplified Compound 3, Exemplified Compound 4, Exemplified Compound 5, Exemplified Compound 7 and Exemplified Compound 9, and the comparative compounds are those shown above. << Evaluation >> The toners 1 to 6, the comparative toners 1 to 3, the magnetic toners 1 to 6 and the comparative magnetic toners 1 to 3 were evaluated for the charge amount at the initial stage and in the actual copying and the image as follows.

For Toners 1 to 6 and Comparative Toners 1 to 3, ferrite carrier coated with silicone resin (volume average particle size = 65 μm) was mixed, and toner concentration was 6%.
Was prepared as a two-component developer and evaluated using a device modified from the fixing device of the Konica copier U-Bix3035.

Magnetic toners 1 to 6 and comparative magnetic toner 1
For 3 to 3, the toner is used as a magnetic one-component developer,
Evaluation was performed using a modified Konica laser beam printer LP-3015.

The fixing conditions used are as follows. . -Fixing using a heat roller The fixing device has a diameter of 30 with a surface coated with tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
It has an upper roller with a heater built in the central part of a cylindrical iron material of mmφ and a lower roller made of silicone rubber with a diameter of 30 mmφ whose surface is coated with tetrafluoroethylene-perfluoroalkyl ether copolymer. . The surface temperature of the upper roller can be set to 110 to 230 ° C.

For fixing, a linear pressure of 0.8 kg / cm and a nip width of 4.3 mm
The printing linear velocity was set to 250 mm / sec.・ Fixing using endless sheet The fixing device is the one shown in FIG.
For 8, a roller impregnated with silicone oil was used.
The fixing conditions are as follows.

Heating body temperature (T ₁ ) 110 to 230 ° C. Film material speed 250 mm / sec Total pressure between heating body and pressure rolls 10 kg Pressure roller, nip between film materials 3 mm Further, as an endless sheet material, on the surface, A 15 μm-thick polyimide film coated with polytetrafluoroethylene in which a conductive substance was dispersed was used.

Using the above-mentioned evaluation machine, printing 100,000 sheets at a room temperature and low humidity environment (20 ° C./10% RH) with a pixel rate of 5%,
The amount of charge of the developer was measured every 10,000 sheets, and the presence or absence of image defects (presence of fogging and presence of offset)
It evaluated by the following evaluation criteria. Blow-off method (TB
-200: manufactured by Toshiba). The results are shown in Tables 5-8.

[Evaluation Criteria] ◯: No fog / offset occurred Δ: Slight fog / offset occurred ×: Fog / offset occurred (two-component toner)

[0069]

[Table 5]

[0070]

[Table 6] (Magnetic toner)

[0071]

[Table 7]

[0072]

[Table 8]

[0073]

INDUSTRIAL APPLICABILITY The present invention provides a toner for electrophotography, which exhibits a stable charging property and gives a good image without character dust and fogging.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a film fixing system using an endless fixing film.

FIG. 2 is an explanatory diagram of a film fixing system using a fixed fixing film.

Claims (4)

[Claims] 1. A toner containing a binder resin, a colorant and a charge control agent, wherein the binder resin has a molecular weight of 1 × 10 ³ to 1 in a molecular weight distribution measured by gel permeation chromatography (GPC). A styrene-acrylic copolymer having at least one peak in the region of 5 × 10 ⁵ and containing 50% or more of a styrene component, wherein the charge control agent is a compound having a melting point of 100 to 200 ° C. Toner characterized by being present. 2. The toner according to claim 1, wherein the melting point of the charge control agent is in the range of 120 to 200 ° C. 3. The charge control agent is a compound having a quaternary ammonium salt structure, wherein the charge control agent is a compound having a quaternary ammonium salt structure.
The toner described in the above. 4. The toner according to claim 3, wherein the compound having a quaternary ammonium salt structure is a compound represented by the following general formula. Embedded image [Wherein R ^{1 to} R ⁴ are substituted or unsubstituted C ^{1 to} C 18
Represents an alkyl group or a substituted or unsubstituted benzyl group, and A ⁻ represents an anion. However, at least one of R ^{1 to} R ⁴ is an alkyl group having 8 to 18 carbon atoms. ]