JPH07271094A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic toner not causing filming and having satisfactory smearing resistance, heat resistance, low-temp. fixability and offset resistance property. CONSTITUTION:This electrophotographic toner contains a resin based on a styrene-acrylic copolymer contg. 5-40wt.% THF-insoluble component as a bonding resin and at least one kind of wax selected from among vegetable natural wax, Fischer-Tropsch wax and montan wax. The amt. of the wax contained is 1-10wt.% of the amt. of the bonding resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in an image forming apparatus such as a copying machine or a printer by an electrophotographic method, and more specifically to an electrophotographic toner used in a heat roll fixing type image forming apparatus. Regarding toner.

[0002]

2. Description of the Related Art Generally, in electrophotography using a dry developing method, a toner obtained by developing an electrostatic latent image on a photoconductor with a toner containing a binder resin and a colorant as a main component, and then developing the electrostatic latent image. The image is transferred onto copy paper and fixed. Although there are various fixing methods, a thermal roll fixing method in which fixing is performed by pressing a heating roll is widely used because of its good thermal efficiency and quick fixing.

In this heat roll fixing system, a so-called offset phenomenon occurs in which the toner which is heated and softened adheres to the surface of the heat roll. Therefore, conventionally, a releasing agent is added to the binder resin to release the toner. I am trying to give it sex.

As the release agent, various waxes such as polyolefin waxes such as low molecular weight polyethylene wax and low molecular weight polypropylene wax and vegetable natural waxes such as carnauba wax and candelilla wax are often used.

[0005]

However, it was not possible to sufficiently satisfy various characteristics required for the toner only by using the above wax as the release agent. For example, in electrophotographic copying machines of recent years, the toner is required to have fixability (low temperature fixability) at a fixing temperature of 150 ° C. or lower for the purpose of shortening the warm-up time of the fixing device and high-speed copying. However, when a polyolefin wax is used as a release agent, the low-temperature fixability of the toner is not sufficient, and depending on the binder resin, the release agent may separate from the binder resin and form a film on the photoreceptor. I had to do it. When a wax having a low melting point such as a vegetable natural wax is used as a release agent,
Although the low-temperature fixability of the toner is improved, there is a problem in heat resistance such that the toner is fused and aggregated in a high-temperature environment.

On the other hand, as a matter of course, the stability of the toner after completion of fixing is also required for the electrophotographic toner of such a heat roll fixing system. For example, a phenomenon in which toner smear occurs on the back surface of the upper paper when a stacked toner image-fixed paper is rubbed under a load, that is, so-called smear does not occur, that is, excellent smear resistance is required. To be However, conventionally, there is no example in which a binder resin and a release agent have been studied for the purpose of improving the smear resistance, the filming described above does not occur, and both heat resistance and smear resistance are obtained. We have not been able to obtain anything that satisfies us.

As described above, by simply using a conventionally known wax or the like as a releasing agent, a toner exhibiting good offset resistance, low temperature fixing property, heat resistance and smear resistance can be obtained without causing filming. I couldn't.

The present invention solves the above problems in the electrophotographic toner containing a release agent for preventing offset, does not cause filming on the photosensitive member, and An object of the present invention is to provide an electrophotographic toner having good smear resistance, heat resistance, low-temperature fixability, and offset resistance.

[0009]

Means for Solving the Problems As a result of repeated studies to solve the above-mentioned problems, the present inventor has found a network-like structure which has been proposed in the past and is insoluble in an organic solvent such as acetone or tetrahydrofuran. It has been found that when a toner binder resin containing a component having a three-dimensional structure (crosslinking component) is used, the strength of the resin as a whole is improved and smear is prevented, that is, smear resistance is improved.

As such a cross-linking component-containing resin, a resin whose main component is a styrene-acrylic copolymer containing a tetrahydrofuran insoluble matter is selected, and this is used as a binder resin, and a plant is used as a release agent. Of water-soluble wax, Fischer-Tropsch wax, or montan wax improves the compatibility of the release agent with the resin, does not cause filming of the release agent on the photoconductor, smear resistance, heat resistance, and low temperature. It was found that the fixing property can be improved at the same time.

The reason why the compatibility of the cross-linking component-containing resin with the wax is improved by the presence of the above waxes is not clear, but the above waxes include acid components and ester components.
It has components other than carbon and hydrogen, and it is considered that this contributes to improving the compatibility with resins.

The present invention has been made on the basis of the above findings, and uses as a binder resin a resin containing a styrene-acrylic copolymer containing tetrahydrofuran insoluble matter in an amount of 5 to 40% by weight as a main component. At least one wax selected from the group consisting of vegetable wax, Fischer-Tropsch wax and montan wax is contained in an amount of 1 to 10% by weight based on the total binder resin.

The term "tetrahydrofuran (THF) insoluble matter" as used herein means that measured by the following method.

First, a predetermined weight of resin is put into a container, a large amount of THF is added, and stirring is carried out for 24 hours to dissolve the resin. After allowing this to stand for 24 hours, the supernatant is removed.
Then, the sediment was dried and weighed, and the ratio of the weight of the sediment to the weight of the resin used was taken as the insoluble matter.

Examples of the monomer of the styrene component constituting the styrene-acrylic copolymer used in the present invention include styrene, o-methylstyrene, m-methylstyrene, p-
Methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, pn-octyl styrene, pn dodecyl styrene, p-phenyl styrene, 3,4- Examples thereof include styrenes such as dichlorostyrene and derivatives thereof.

The monomer of the acrylic component constituting the styrene-acrylic copolymer used in the present invention is methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate. , Dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, Dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, methacrylic acid Methylaminoethyl, diethylaminoethyl methacrylate, acrylic acid, and methacrylic acid.

The above-mentioned monomer or monomer mixture can be polymerized by any method such as suspension polymerization, solution polymerization, emulsion polymerization and bulk polymerization.

The crosslinking agent used in the toner of the present invention is
Examples thereof include divinylbenzene, bis (4-acryloxypolyethoxyphenyl) propane, ethylene glycol diacrylate, and 1,3-butylene glycol diacrylate.

The resin containing a styrene-acrylic copolymer as the main component used in the present invention has a THF insoluble content of 5 to 5.
It is 40% by weight, preferably 10 to 25% by weight. If the THF insoluble content is lower than 5% by weight, the proportion of the cross-linking component is too small to exert its effect, and if it exceeds 40% by weight, the resin becomes too hard and melt-kneading or pulverization becomes difficult to make the production impossible.

Examples of the natural vegetable wax used in the present invention include carnauba wax and candelilla wax. The vegetable natural wax, Fischer-Tropsch wax and montan wax used in the present invention can be used alone or in combination of two or more kinds, and further, these waxes, low molecular weight polyethylene wax and low molecular weight oxidized polyethylene can be used. It is also possible to use in combination with a wax, a low molecular weight polypropylene wax, a polyolefin wax such as a low molecular weight oxidized polypropylene wax, or the like. By combining the polyolefin wax, the fixing temperature region (non-offset region) where offset does not occur can be widened.

The content of the wax used in the present invention is 1 to 10% by weight based on the total binder resin. When the polyolefin wax is used in combination, it is 50 to 200% by weight based on the total weight of the natural vegetable wax, Fischer-Tropsch wax and montan wax.
It is preferable to use the above polyolefin wax.

The toner of the present invention may be used as a magnetic toner. In this case, known magnetic fine particles may be dispersed in a binder resin. As the magnetic material, for example, cobalt,
Ferromagnetic metals such as iron and nickel, alloys of metals such as cobalt, iron, nickel, aluminum, lead, magnesium, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten and vanadium, A known magnetic material such as a mixture of these metals, an oxide, and a fired body (ferrite) can be used. These magnetic materials are used as the binder resin 10 for the toner.
0 to 80 parts by weight, preferably 5 to 60 parts by weight
It may be added by weight.

The toner of the present invention has an average particle size of 2 to 20 μm.
It can be used in the range of m. Further, the toner of the present invention is
It can be used in both a one-component developer which does not use a carrier and a two-component developer which is used together with a carrier. As the carrier used with the toner of the present invention, a known carrier can be used, for example, a carrier composed of magnetic particles such as iron powder and ferrite, and a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as resin. Alternatively, a dispersion type carrier obtained by dispersing fine magnetic powder in a binder resin can be used. As the carrier, it is desirable to use a carrier in which magnetic particles are coated with a polyolefin-based resin from the viewpoints of durability and spent resistance of the carrier.

Examples of the charge control agent used in the present invention include nigrosine, nitrogen-containing resins and quaternary ammonium salts. When the charge control agent is dispersed and contained in the toner, 0.1 to 20 parts by weight, preferably 0.1 to 10 parts by weight of the charge control agent is added to 100 parts by weight of the binder resin of the toner. It is desirable to use a charge control agent as a toner.
To attach and fix to the surface of the toner, the binder resin 1 of the toner
It is desirable to add 0.001 to 10 parts by weight, preferably 0.05 to 2 parts by weight of the charge control agent to 100 parts by weight.

Further, the toner according to the present invention is preferably surface-treated with a fluidizing agent. The fluidizing agent is added by mechanically mixing the toner and the fluidizing agent. It is desirable to do. Examples of the fluidizing agent include silica particles, titanium dioxide particles, alumina particles, magnesium fluoride particles, silicon carbide particles, boron carbide particles, titanium carbide particles, zirconium carbide particles, boron nitride particles, titanium nitride particles, zirconium nitride particles, magnetite. Fine particles, molybdenum disulfide fine particles, aluminum stearate fine particles, magnesium stearate fine particles, zinc stearate fine particles,
Fluorine-based resin particles, acrylic resin particles, etc. may be used alone or in combination of two or more kinds.

The addition amount of the fluidizing agent is 0.
It is from 05 to 2% by weight, preferably from 0.1 to 1% by weight.
If the amount added is less than 0.05% by weight, the fluidity of the toner will be insufficient, and if it is more than 2% by weight, the environmental stability will be impaired, especially when the toner is charged in a high temperature and high humidity environment. There is a problem of decrease in quantity. Further, it is preferable to use a fluidizing agent as the fluidizing agent, and as the hydrophobizing agent, a silane coupling agent,
Titanium coupling agents, higher fatty acids, silicone oils, etc. can be used.

[0027]

【Example】

<Toner Production Example 1> 3000 g of xylene was placed in a circular tube separable flask equipped with a cooling tube, a stirrer, a gas introduction tube, and a thermometer, and heated to reflux xylene. Then, a mixture of 210 parts by weight of styrene, 90 parts by weight of n-butyl acrylate and 0.5 parts by weight of a polymerization initiator (V-59, manufactured by Wako Pure Chemical Industries, Ltd.) was applied appropriately for about 30 minutes. After completion of the appropriate conditions, the mixture was refluxed for 2 hours to complete the first polymerization.

Subsequently, 140 parts by weight of styrene, 60 parts by weight of n-butyl acrylate, 1.2 parts by weight of divinylbenzene and 0.2 of a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.).
Part by weight of the mixture was dispensed over about 20 minutes. After completion of the appropriate conditions, the mixture was refluxed for 4 hours to complete the second polymerization. Xylene was removed from this using a vacuum distillation apparatus until the non-volatile content became approximately 85 to 90%, and the non-volatile content was 99.7% with a heating vacuum dryer.
The solvent was removed until the above.

The THF-insoluble matter of the resin thus obtained was 20% by weight. When the molecular weight of the THF-soluble component of the above resin was measured by gel permeation chromatography (GPC), the number average molecular weight (Mn) was 1300.
0, the weight average molecular weight (Mw) was 210000.
The glass transition point (Tg) was 65.8 ° C. This resin is referred to as a polymer a.

Next, the following materials were thoroughly mixed by a ball mill and then thoroughly mixed on a three-roll heated to 140 ° C. -Polymer a 100 parts by weight-Carbon black (Mogul L: manufactured by Cabot) 8 parts by weight-Candelilla wax 5 parts by weight-Nigrosine (NB-EX: manufactured by Orient Chemical Co.) 4
By weight, the kneaded product was left standing to cool, coarsely pulverized using a feather mill, and further finely pulverized by a jet mill. next,
Wind power classification was performed to obtain a fine powder having an average particle size of 11 μm. 100 parts by weight of this fine powder and hydrophobic silica fine powder (H-200
(0/4: Hoechst) 0.2 part by weight was mixed with a Henschel mixer to obtain a toner A.

<Production Example 2 of Toner> A polymer b was produced in the same procedure as in Production Example 1 of toner. However, for the first polymerization, a mixture of 195 parts by weight of styrene, 105 parts by weight of n-butyl methacrylate, and 0.5 parts by weight of a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.) was used. For the polymerization, a mixture of 130 parts by weight of styrene, 70 parts by weight of n-butyl methacrylate, 1.2 parts by weight of divinylbenzene and 0.2 parts by weight of a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.) was used. . The THF-insoluble content of the polymer b was 20% by weight, and the GPC molecular weight of the THF-soluble component was Mn = 10000, Mw = 22.
At 3000, Tg = 62.3 ° C.

Then, the following materials were used to obtain fine powder having an average particle size of 11 μm by the same procedure as in the toner production example 1. -Polymer b 100 parts by weight-Carbon black (Regal 330R: manufactured by Cabot) 10 parts by weight-Candelilla wax 5 parts by weight This fine powder 100 parts by weight and hydrophobic titanium oxide fine powder (MT-600BS: manufactured by Teika). ) 0.6 part by weight was mixed with a Henschel mixer to obtain a toner B.

<Toner Production Example 3> Polymer c was produced in the same procedure as in Toner Production Example 1. However, in the first polymerization, 195 parts by weight of styrene, 90 parts by weight of n-butyl methacrylate, 15 parts by weight of methyl methacrylate and 0.3 part by weight of a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.) Using the mixture, for the second polymerization, 130 parts by weight of styrene, 60 parts by weight of n-butylbutyl methacrylate, 10 parts by weight of methyl methacrylate, 1.2 parts by weight of divinylbenzene and a polymerization initiator (V-59: Wako Pure). 0.1 part by weight of the mixture was used. The THF insoluble content of the polymer c was 20% by weight, the GPC molecular weight of the THF soluble component was Mn = 8700,
The Mw was 189000 and the Tg was 68.4 ° C.

Then, the following materials were used to obtain fine powder having an average particle diameter of 11 μm by the same procedure as in the toner production example 1. -Polymer c 100 parts by weight-Carbon black (Regal 330R: manufactured by Cabot) 10 parts by weight-Fischer-Tropsch wax (Sazol H1: manufactured by Sazol Corporation) 5 parts by weight-Nitrogen-containing resin (Luna Pel 912: manufactured by Arakawa Chemical Co., Ltd.) 3
By weight 100 parts by weight of this fine powder and 0.4 parts by weight of hydrophobic titanium oxide fine powder (OK-18: manufactured by Teika) were mixed with a Henschel mixer to obtain a toner C.

<Production Example 4 of Toner> A polymer d was produced in the same procedure as in Production Example 1 of toner. However, a mixture of 195 parts by weight of styrene, 105 parts by weight of n-butyl methacrylate and 5 parts by weight of a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.) was used for the first polymerization, and for the second polymerization. Is 130 parts by weight of styrene, 70 parts by weight of n-butyl methacrylate,
2 parts by weight of divinylbenzene and a polymerization initiator (V-5
9: manufactured by Wako Pure Chemical Industries, Ltd.) 2 parts by weight of the mixture was used. The THF insoluble content of the polymer d is 35% by weight, and the THF soluble component GP
C molecular weight is Mn = 6300, Mw = 186000, T
It was g = 60 ° C.

Then, the following materials were used to obtain fine powder having an average particle size of 11 μm by the same procedure as in the toner production example 1. -Polymer d 100 parts by weight-Carbon black (Elftex 8: manufactured by Cabot) 10 parts by weight-Carnava wax 5 parts by weight-Nitrogen-containing resin (Luna Pale 912: manufactured by Arakawa Chemical Co., Ltd.) 3
100 parts by weight of this fine powder and 0.4 parts by weight of hydrophobic titanium oxide fine powder (OK-18: manufactured by Teika) were mixed with a Henschel mixer to obtain a toner D.

<Production Example 5 of Toner> A polymer e was produced in the same procedure as in Production Example 1 of toner. However, in the first polymerization, 240 parts by weight of styrene and 6 parts of n-butyl acrylate were used.
0 parts by weight and a polymerization initiator (V-59: manufactured by Wako Pure Chemical Industries, Ltd.)
0.5 parts by weight of the mixture was used, and in the second polymerization, 160 parts by weight of styrene, 40 parts by weight of n-butyl acrylate, 0.6 parts by weight of divinylbenzene and a polymerization initiator (V-5
9: Wako Pure Chemical Industries, Ltd.) 0.2 parts by weight of the mixture was used. The THF insoluble content of the polymer e was 10% by weight, and the GPC molecular weight of the THF soluble component was Mn = 9700, Mw = 209,000.
Thus, Tg was 61 ° C.

Then, the following materials were used to obtain fine powder having an average particle size of 11 μm by the same procedure as in the toner production example 1. Polymer 100 parts by weight Carbon black (Regal 330R: manufactured by Cabot) 10 parts by weight Fischer-Tropsch wax (Sazol H1: manufactured by Sazol Corporation) 5 parts by weight Nigrosine (NB-EX: manufactured by Orient Chemical Co.) 4
By weight 100 parts by weight of this fine powder and 0.4 parts by weight of hydrophobic titanium oxide fine powder (OK-18: manufactured by Teika) were mixed with a Henschel mixer to obtain a toner E.

<Manufacturing Example 6 of Toner> Using the materials shown below, the average particle diameter is 11 by the same procedure as in Manufacturing Example 1 of toner.
A fine powder of μm was obtained. -Polymer b 100 parts by weight-Carbon black (Regal 330R: manufactured by Cabot) 10 parts by weight-Montan wax 5 parts by weight-Quaternary ammonium salt 2 parts by weight Hydrophobic titanium oxide fine particles are added to 100 parts by weight of this fine powder. Toner F was obtained by mixing 0.4 parts by weight of powder (OK-18: manufactured by Teika) with a Henschel mixer.

<Production Example 7 of Toner> An average particle size of 11 was obtained by using the following materials in the same procedure as in Production Example 1 of toner.
A fine powder of μm was obtained. -Polymer b 100 parts by weight-Carbon black (Elftex 8: manufactured by Cabot) 10 parts by weight-Polypropylene wax (Viscor 550P: manufactured by Sanyo Kasei) 2 parts by weight-Fischer-Tropsch wax (Sazol H1: manufactured by Sazol Corporation) 3 parts by weight Part ・ Nitrogen-containing resin (Luna Pale 912: Arakawa Chemical Co., Ltd.) 3
By weight To 100 parts by weight of this fine powder, 0.5 parts by weight of hydrophobic titanium oxide fine powder (T-805: manufactured by Nippon Aerosil Co., Ltd.) was mixed with a Henschel mixer to obtain a toner G.

<Production Example 8 of Toner> An average particle diameter of 11 was obtained by using the following materials and following the same procedure as in Production Example 1 of toner.
A fine powder of μm was obtained. -Polymer a 100 parts by weight-Carbon black (Raven 1250: Colombia Carbon Co., Ltd.) 10 parts by weight-Polypropylene wax (Viscor 550P: Sanyo Kasei Co., Ltd.) 3 parts by weight-Carnava wax 2 parts by weight-Nigrosine (NB-EX: Orient Chemical Co., Ltd.) 2
By weight To 100 parts by weight of this fine powder, 0.2 parts by weight of hydrophobic silica fine powder (H-2000 / 4: manufactured by Hoechst) was mixed with a Henschel mixer to obtain a toner H.

<Production Example 9 of Toner> 3000 g of xylene was placed in a circular tube separable flask equipped with a cooling tube, a stirrer, a gas introduction tube and a thermometer, and heated to reflux xylene. And 240 parts by weight of styrene, 60 parts by weight of n-butyl acrylate and a polymerization initiator (V-5
(9: manufactured by Wako Pure Chemical Industries, Ltd.) 5 parts by weight of the mixture was applied for about 30 minutes. After completion of the appropriate conditions, the mixture was refluxed for 2 hours to complete the polymerization. The non-volatile content of this was reduced to about 85-90 by a vacuum distillation device.
The xylene was removed until the content reached 0.1%, and the solvent was removed by a heating vacuum dryer until the nonvolatile content reached 99.7% or more.

The resin thus obtained had a THF insoluble content of 0% by weight, and the THF-soluble component had a GPC molecular weight of Mn = 1130.
0, Mw = 240000, and Tg = 63.8 ° C. This resin is referred to as polymer f.

Then, the following materials were used to obtain fine powder having an average particle diameter of 11 μm by the same procedure as in Toner Production Example 1. -Polymer f 100 parts by weight-Carbon black (Elftex 8: manufactured by Cabot) 10 parts by weight-Polypropylene wax (Viscor 550P: manufactured by Sanyo Kasei Co., Ltd.) 5 parts by weight-Nigrosine (NB-EX: manufactured by Orient Chemical Co., Ltd.) 4
Parts by weight To 100 parts by weight of this fine powder, 0.2 parts by weight of hydrophobic silica fine powder (H-2000 / 4: manufactured by Hoechst) was mixed with a Henschel mixer to obtain toner I.

<Manufacturing Example 10 of Toner> Using the materials shown below, the same procedure as in Manufacturing Example 1 of toner was used to obtain an average particle size of 1
A fine powder of 1 μm was obtained. -Polymer c 100 parts by weight-Carbon black (Elftex 8: manufactured by Cabot) 10 parts by weight-Polyethylene wax 5 parts by weight-Nitrogen-containing resin (Luna Pale 912: manufactured by Arakawa Chemical Co., Ltd.) 3
By weight To 100 parts by weight of this fine powder, 0.2 parts by weight of hydrophobic silica fine powder (R-974: manufactured by Nippon Aerosil Co., Ltd.) was mixed with a Henschel mixer to obtain toner J.

<Toner Production Example 11> Toner K was obtained by the same procedure as in Toner Production Example 9 except that the polypropylene wax of Toner Production Example 9 was changed to Carnauba wax.

<Manufacturing Example 12 of Toner> The polymer a and the polymer f were coarsely pulverized using a feather mill to obtain a resin powder a and a resin powder f. The resin powder a and the resin powder f were sufficiently mixed in a ball mill at a ratio of 1: 9 to obtain a resin powder g. The THF insoluble content of this resin powder g was 2% by weight.

Next, the following materials were used to obtain fine powder having an average particle size of 11 μm by the same procedure as in Toner Production Example 1. Resin powder g 100 parts by weight Carbon black (Mogul L: manufactured by Cabot) 8 parts by weight Carnava wax 5 parts by weight Nigrosine (NB-EX: manufactured by Orient Chemical Co., Ltd.) 4
Parts by weight To 100 parts by weight of this fine powder, 0.2 parts by weight of hydrophobic silica fine powder (H-2000 / 4: manufactured by Hoechst) was mixed with a Henschel mixer to obtain a toner L.

<Manufacturing Example 13 of Toner> Using the materials shown below, the same procedure as in Manufacturing Example 1 of toner was used to obtain an average particle size of 1
A fine powder of 1 μm was obtained. -Polymer b 100 parts by weight-Carbon black (Regal 330R: manufactured by Cabot Corporation) 10 parts by weight-Quaternary ammonium salt 2 parts by weight 100 parts by weight of this fine powder and hydrophobic titanium oxide fine powder (MT-600BS: Teika) (Manufactured by the same company) 0.6 part by weight was mixed with a Henschel mixer to obtain a toner M.

Table 1 shows the types of binder resins, the THF insoluble content (% by weight) of the resins, the types of release agents, and the types of charge control agents for the toners of the respective production examples.

[0051]

[Table 1]

<Production Example 1 of carrier> In a flask having an internal area of 500 ml, which had been replaced with argon, dehydrated n-heptane 20 was added.
0 ml and 15 g (25 mmol) of magnesium stearate which had been dehydrated in advance at 120 ° C. under reduced pressure (2 mmHg) were added to form a slurry at room temperature. Furthermore, while stirring, 0.44 g (2.3 mmol) of titanium tetrachloride is appropriately added. After the temperature was appropriately adjusted, the temperature was started and the reaction was carried out under reflux for 1 hour to obtain a viscous transparent titanium-containing catalyst component solution.

Next, 500 ml of dehydrated hexane and 20 ml were placed in an autoclave having an internal volume of 1 liter which was replaced with argon.
450 g of sintered ferrite powder (average particle size 50 μm) dried under reduced pressure (2 mmHg) at 0 ° C. for 3 hours was added, and stirring was started at room temperature. Then, the temperature is raised to 40 ° C., and the solution of the titanium-containing catalyst component is converted into titanium atoms to 0.02.
Mmol was added and the reaction was carried out for about 1 hour. After that, carbon black (Ketc
hen Black DJ-600: manufactured by Lion Akzo) 0.47 g was added. The carbon black used was one that had been dried under reduced pressure at 200 ° C. for 1 hour and then slurried with dehydrated hexane.

Further, 2.0 mmol of triethylaluminum and 2.0 mmol of diethylaluminum chloride were added, and the temperature was raised to 90 ° C. The internal pressure at this time is 1.5k
It was g / cm ² G. Then, hydrogen is supplied and 2 kg /
After boosting to the cm ² G, the total pressure was carried out for 45 minutes polymerization while continuously feeding ethylene to keep the 6kg / cm ² G, to obtain a ferrite and carbon black-containing polyethylene composition of the total amount of 469.3g .

The powder obtained by drying the above composition was uniformly black, and when observed by an electron microscope, the ferrite surface was thinly covered with polyethylene, and the carbon black was uniformly dispersed in this polyethylene. When the composition was measured by thermogravimetric analysis,
The filling rate of the core material was 95.5% by weight, and the weight ratio of ferrite, polyethylene, and carbon black was 24: 1: 0.025 when calculated from the charged amount.

Then, the above composition was put into a hot air stream set at 120 ° C., and a heat treatment was carried out for 2 hours, and then 10
The aggregate was removed by classification with a 6 μm sieve to obtain a carrier I having an electric resistance of 3.5 × 10 ⁸ Ω · cm.

The electric resistance of the carrier was measured as follows. Thickness of 1 mm and diameter of 5 on a circular metal electrode
Place the sample so that it will be 0 mm, and put a mass of 8 on it.
95.4 g, 20 mm diameter electrode and 38 mm inner diameter,
A guard electrode having an outer shape of 42 mm was placed and a DC voltage of 500 V was applied. Read the current value 1 minute after applying the voltage,
It was converted to the volume resistivity ρ of the sample. Measurement environment temperature is 25
± 1 ° C., relative humidity was 55 ± 5%, the measurement was repeated 5 times, and the average value was taken as the measured value.

<Manufacturing Example 2 of Carrier> A total amount of 469.3 g of ferrite and carbon black was obtained by the same procedure as in Manufacturing Example 1 of carrier, except that 1.50 g of DB # 2350 manufactured by Mitsubishi Kasei Co. was used as the carbon black. A containing polyethylene composition was obtained.

The powder obtained by drying the above composition was uniformly black, and when observed by an electron microscope, the ferrite surface was thinly covered with polyethylene, and the carbon black was uniformly dispersed in this polyethylene. When the composition was measured by thermogravimetric analysis,
The core material filling rate was 95.5% by weight, and the weight ratio of ferrite, polyethylene, and carbon black was 24: 1: 0.08 when calculated from the charged amounts.

Thereafter, the above composition was put into a hot air stream set at 120 ° C., and a heat treatment was carried out for 2 hours, then 10
Aggregates were removed by classification with a 6 μm sieve to obtain a carrier II having an electric resistance of 5.0 × 10 ⁸ Ω · cm.

<Production Example 3 of Carrier> A thermosetting silicone resin solution (KR-255: manufactured by Shin-Etsu Silicone Co., Ltd.) was added to Sintered Ferrite Particles (F-300: manufactured by Powdertech Co., Ltd.) and Spiracoater SP-40. (Made by Okada Seiko)
Was applied. At that time, spray pressure 3.5 kg / c
m, spray amount 40 g / min, and temperature 50 ° C., and repeatedly applied so as to obtain a coating of 1.0% by weight with respect to the ferrite particles.

Next, the temperature inside the room was raised to 150 ° C. to cure the resin. The aggregate was removed using a 106 μm sieve to obtain a coated carrier III having an average particle diameter of 55 μm and an electric resistance value of 7.5 × 10 ⁸ Ω · cm.

<Production Example 4 of Carrier> Polyester resin (Mn = 5000, Mw = 115000, Tg = 67)
C., softening point = 123.degree. C.) 100 parts by weight, ferrite fine particles (MFP-2: manufactured by TDK) 500 parts by weight, and colloidal silica dispersant (Aerosil # 200: manufactured by Nippon Aerosil Co., Ltd.) 3 parts by weight. After sufficiently mixing with, melt-kneading with a two-extrusion kneader, cooling, coarsely pulverizing, finely pulverizing with a jet mill, and further using an air classifier, an average particle diameter of 60 μm and an electric resistance value of 5.8. × 10 ¹³
The dispersion type carrier IV of was obtained.

Example 1 Toner A and Carrier IV were mixed at a weight ratio of 5:95 to prepare a developer. The mixing ratios of toner and carrier in each of the following Examples and Comparative Examples were the same as those in this Example.

Example 2 Toner B and Carrier II were mixed to prepare a developer.

Example 3 Toner C and carrier I were mixed to prepare a developer.

Example 4 Toner D and carrier I were mixed to prepare a developer.

Example 5 Toner E and Carrier III were mixed to prepare a developer.

Example 6 Toner F and carrier I were mixed to prepare a developer.

Example 7 Toner G and carrier I were mixed to prepare a developer.

Example 8 Toner H and Carrier IV were mixed to prepare a developer.

Comparative Example 1 Toner I and Carrier IV were mixed to prepare a developer.

Comparative Example 2 Toner J and Carrier I were mixed to prepare a developer.

Comparative Example 3 Toner K and Carrier IV were mixed to prepare a developer.

Comparative Example 4 Toner L and Carrier IV were mixed to prepare a developer.

<Comparative Example 5> Toner M and carrier I were mixed to prepare a developer.

An actual copying test was conducted using each of the developers thus prepared, and the smear resistance, the presence or absence of filming on the photosensitive member, the heat resistance, the low temperature fixing property, and the non-offset area were examined. The above items were evaluated as follows.

<Evaluation of smear resistance> A solid was fixed on copy paper (EP paper manufactured by Minolta Camera) using a commercially available electrophotographic copying machine EP-410Z (manufactured by Minolta Camera). Next, a copy paper and a weight of 200 g were placed on the fixed image, and the weight was rotated once by a motor. Then, the occurrence of smear was judged based on how dirty the copy paper placed on top was. Specifically, the ID value was measured with a densitometer, and smear resistance was evaluated according to the following criteria. ⊚: ID <0.05 ∘: 0.05 ≦ ID <0.1 x: ID ≧ 0.1 If the evaluation is ⊚ or ∘, there is no practical problem.

<Presence or absence of filming> After performing a live-copy test of 50,000 sheets with a commercially available electrophotographic copying machine EP-410Z (manufactured by Minolta Camera Co., Ltd.), the presence or absence of filming on the photoreceptor is visually confirmed. At the same time, the presence or absence of filming was judged by developing the solid and observing whether white spots due to filming appear.

<Evaluation of heat resistance> 5 g of the toner was placed in a 50 cc glass bottle, and after storing it in an environment of 50 ° C. for 24 hours, the degree of aggregation of the toner was visually observed and evaluated according to the following criteria. ⊚: No aggregates, no change from before storage ◯: Agglomerates are generated in part, but if the bottle is shaken, it breaks up and there is no practical problem. X: Aggregates are generated on the whole, and even if the bottle is shaken, the aggregates are not crushed.

<Evaluation of low temperature fixability> Using a commercially available electrophotographic copying machine EP5400 (manufactured by Minolta Camera Co.), ID
A solid with a value of 1.2 is developed, and this is fixed with an external fixing device of a heat roll type at a fixing temperature of 140 ° C. and a paper feeding speed of 250.
It was fixed on copy paper (EP paper manufactured by Minolta Camera Co., Ltd.) at a speed of mm / sec.

Then, a sand eraser is put on the fixed image,
A load of 1 Kg was applied, and rubbing was performed 6 times. The image densities before and after rubbing were measured, and the ratio of the image density after rubbing to the image density before rubbing was calculated. If this ratio is 80% or more, there is no practical problem.

<Measurement of Non-Offset Area> A solid is developed by a commercially available electrophotographic copying machine EP-410Z (manufactured by Minolta Camera Co., Ltd.), and the solid is developed at various fixing temperatures by an external fixing device of a heat roll system (Minolta camera). It was fixed on EP paper manufactured by Camera Co.). The non-offset area was measured by visually observing the presence or absence of offset on the fixing roller of the copying machine at this time.

The results of the live-action test are summarized in Table 2. In Comparative Example 5, the offset was severe and the low temperature fixability could not be measured.

[0085]

[Table 2]

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As a binder resin, a resin containing a styrene-acrylic copolymer containing a tetrahydrofuran insoluble component as a main component is used, and further, a vegetable natural wax, Fischer-Tropsch wax, or montan wax is released as a release agent. When a mold additive is used, the compatibility between the mold release agent and the resin is improved, so filming does not occur, and good smear resistance, heat resistance, low-temperature fixability, and offset resistance are obtained. The electrophotographic toner shown can be obtained.

Claims (1)

[Claims] 1. A resin containing a styrene-acrylic copolymer as a main component containing 5 to 40% by weight of tetrahydrofuran insoluble matter as a binder resin, and comprises a natural vegetable wax, Fischer-Tropsch wax and montan wax. An electrophotographic toner comprising at least one wax selected from the group in an amount of 1 to 10% by weight based on the entire binder resin.