JPH0611894A - Electrophotographic toner - Google Patents

Abstract

(57) [Summary] [Objective] An electrophotographic toner capable of easily controlling the triboelectric charge amount with a carrier so as to be suitable for various developing methods.
To get a developer. [Structure] A polyester resin comprising a diol component, an acid component containing 1 to 50 mol% of a divalent carboxylic acid (or its anhydride) and trimellitic acid (or 10 to 30 mol% of its anhydride), and further represented by the formula (III) The toner containing the fluorine-containing quaternary ammonium salt compound represented by the following is combined with a carrier having a conductive resin-containing silicone resin coating.

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 electric latent image in electrophotography, electrostatic printing and the like. Particularly, in the heat roll fixing method, the present invention relates to a toner that is sufficiently fixed at a lower temperature and that does not affect developer characteristics such as charging characteristics even when used for a long time in a developing device.

[0002]

2. Description of the Related Art An electrostatic image formed by an electrophotographic method, an electrostatic printing method, an electrostatic recording method, etc., in the case of a dry method, is generally developed with a dry toner mainly containing a binder resin and a colorant and then copied. Transferred and fixed on paper. Although there are various fixing methods for toner images, the heat roller fixing method is widely used because of its high thermal efficiency and high-speed fixing. When performing high-speed fixing with such a heat fixing method, the toner is required to have good low-temperature fixing property (that is, the lower limit fixing temperature is low), and therefore, a binder resin having a low softening point is used. To be done. However, when a low softening point resin is contained in the toner, a part of the toner image adheres to the surface of the heat roller at the time of fixing, and this transfers to the copy paper to cause scumming, a so-called offset property and winding phenomenon (particularly It often occurs when the heat roller temperature is low). Therefore, as means for preventing these phenomena, JP-A Nos. 51-143333, 57-148752, 58-97056 and 60
-247250 and the like propose to add solid silicone varnish, higher fatty acid, higher alcohol, various waxes, etc. as a release agent, but all of them have sufficient offset resistance while maintaining good low temperature fixing property. Also, there is no known one exhibiting wrapping resistance, improvement in low-temperature fixing property and offset resistance by a binder resin, and toner coagulation property during storage stability (hereinafter referred to as heat-resistant storage property).
Needs improvement.

Further, the toner as described above holds a positive or negative charge depending on the polarity of the electrostatic image to be developed. In order to allow the toner to retain an electric charge, the triboelectric charging property of the resin, which is a component of the toner, can be used, but in this method, the toner charging property is small, so the image obtained by development is easily fogged and is not clear. Will be things. Therefore, in order to impart a desired triboelectric chargeability to the toner, a dye, a pigment or a polarity control agent which imparts the chargeability is added. Conventionally, as load-bearing charge control agents, metal complex salts of monoazo dyes, nitrohumic acid and its salts, salicylic acid, naphthoic acid, cobalt of dicarboxylic acids, metal complexes such as chromium and iron, sulfonated copper phthalocyanine pigments, nitro groups, halogens. There are styrene oligomers, chlorinated paraffins, melamine resins, etc., which have been introduced, but especially few of them show good negative chargeability in combination with a carrier containing a silicone resin in the coating layer.

Further, these dyes have a complicated structure, their properties are not constant, and their stability is poor. Further, during thermal kneading, decomposition or mechanical shock, friction, changes in temperature and humidity conditions, and the like are likely to cause decomposition or deterioration, and a phenomenon in which charge controllability is deteriorated is likely to occur. In many cases, the chargeability changes depending on the environment.
Furthermore, when a conventional toner containing the charge control agent is used for a long time, filming may occur on the surface of the photoconductor due to poor charging.

In addition, because of the advantages such as resistance to PVC mat fusion and that the original color of the color material of the color toner is not impaired,
Recently, polyester resins are often used as binder resins. However, when a polyester resin is used as a binder resin in a toner, in any case, even if the charge amount is low, or even if it is high, the charge amount decreases with repeated use, and fog or toner scattering occurs, which is difficult to use. There was a problem. It is considered that this is because functional groups such as —COOH and —OH groups remain in the polyester resin due to its chemical structure, which hinders maintaining stable chargeability. Furthermore, a carrier containing a silicone resin in the coating layer has low negative chargeability and poor environmental stability when triboelectrically charged with a toner having a polyester resin as a binder, so that the charging characteristics are stable and good development is achieved. No drug has been obtained.

Further, the difference between the triboelectric charge amount under high temperature and high humidity and the triboelectric charge amount under low temperature and low humidity [(hereinafter, referred to as Q / M (triboelectric charge amount Q coulomb / toner weight Mg) environmental change] becomes large, There is a problem that the image density is likely to change while copying is repeated for a long time.

Conventionally, as a mechanism of a two-component dry developer, fine toner particles are formed on the surface of relatively large particles.
It is held by the electric force generated by the friction of both particles, and when the electrostatic latent image is approached, the attraction force in the latent image direction to the toner particles by the electric field formed by the electrostatic latent image is generated between the toner particles and the carrier particles. It is believed that the toner particles are attracted and adhered onto the electrostatic latent image by virtue of the binding force of the electrostatic latent image to be visualized. Since the developer is repeatedly used while replenishing the toner consumed by the development, the carrier must always triboelectrically charge the toner particles to a desired polarity and a sufficient charge amount during long-term use.
However, in the conventional developer, a toner film is formed on the carrier surface due to collision between particles, mechanical collision such as collision between particles and a developing device, or heat generated by these effects, so-called toner spent formation occurs. However, the charging characteristics of the carrier deteriorate with the use time, and it becomes necessary to replace the entire developer.

In order to prevent such spent formation,
Conventionally, a method of coating various resins on the surface of a carrier has been proposed, but a satisfactory method has not been obtained yet. For example, a carrier coated with a resin such as a styrene-acrylate copolymer or a styrene polymer has excellent charging characteristics, but has a relatively high critical surface tension on the surface, and therefore, after repeated copying, spent is formed again. The life as a developer was not so long.

On the other hand, a carrier coated with a silicone resin having a low critical surface tension has been proposed.
Since the silicone resin has low mechanical strength, carrier particles may collide with the inner wall of the developing device or the surface of the photosensitive member due to strong stirring such as in a high-speed copying machine or stirring for a long time in the developing device, or When particles collide with each other, the silicone resin coating layer wears and peels off with time, and the frictional charge changes from the charge between the toner and the silicone resin to the charge between the toner and the carrier core particles. There is a problem that the amount cannot be kept constant and the image quality is deteriorated.
Further, when the carrier particles are coated with a silicone resin, the silicone resin itself has a high electric resistance, so that when it is used as a developer, the image quality is deteriorated due to edge development and charge accumulation development. On the other hand, a method has been proposed in which a conductive substance such as carbon black is added to the silicone resin coating layer to control the electric resistance of the carrier.

As the toner applied to such a carrier, fine powder in which a colorant such as carbon black is dispersed in a binder resin made of natural resin or synthetic resin is used. For example, particles obtained by finely pulverizing a resin obtained by branching a colorant into a binder resin such as polystyrene to have a particle size of about 1 to 30 μm are used as a toner.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to have sufficient offset resistance at the time of fixing, have a low fixing lower limit temperature, and prevent winding around a fixing roll.
Still another object is that the Q / M reaches a desired level, there is little Q / M fluctuation due to environmental changes, there is no background stain or toner scattering, and the image has high fidelity equivalent to the initial image even during continuous use. And to provide a toner suitable for high-speed fixing.

[0012]

According to the present invention, in a toner for electrophotography containing a binder resin, a colorant and a polarity control agent as main components, the binder resin of the toner is represented by the following general formula (I).
A divalent carboxylic acid represented by the following general formula (II) in a compound selected from the group consisting of a diol formula component represented by: and a divalent or higher polyvalent carboxylic acid, an anhydride thereof and a lower alkyl ester thereof. A polyester resin obtained by condensation polymerization of the anhydride with an acid component containing 1 to 50 mol% and trimetic acid or 10 to 30 mol% of the anhydride, and further represented by the following general formula (III) as a polarity control agent. The inclusion of the indicated fluorinated quaternary ammonium salt compound has made it possible to solve the above problems. Furthermore, when a metal-containing azo dye is used in combination as the second control agent and the central metal is chromium, cobalt, or iron, the effect is even greater, and by using styrene / acrylic resin in combination as the binder resin for the toner, It has been found that the effect is increased. In addition, a toner image formed by a developer having the above-mentioned toner having a silicone resin coating layer on the surface thereof and a carrier containing conductive fine powder in the coating layer has sufficient offset resistance at the time of fixing and has a lower fixing limit. The temperature is low, there is no wrapping around the fixing roll, there is little Q / M fluctuation due to environmental changes, there is no background stain and toner scattering, and an image with high fidelity equivalent to the initial image is obtained even during continuous use. To be

[0013]

[Chemical 4]

[0014]

[Chemical 5]

[0015]

[Chemical 6]

Next, materials used for the toner of the present invention will be described. Regarding the polyester used as the binder resin used in the present invention, as the amount of trimellitic acid or its anhydride used increases, the impact resistance of the obtained resin improves, but on the other hand, the glass transition point decreases. The storability of the toner at high temperature is likely to deteriorate.

Therefore, trimellitic acid or its anhydride is used in an amount of 10 to 30 mol%, preferably 20 to 30 mol% of the acid component, and the compound represented by the general formula (II) or its anhydride is used as the acid component. 1 to 50 mol% of Examples of the compound represented by the general formula (II) include n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, iso-octyl succinic acid, n-octyl succinic acid, n-butyl succinic acid. And so on. As the remaining compound of the acid component, usual compounds such as fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid and their anhydrides, and lower alkylene steers thereof can be used.

As an example of the diol represented by the general formula (I), polyoxypropylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyester (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (16) -2,2-bis (4-hydroxyphenenyl) propane and the like can be mentioned.

It is also possible to use the following bifunctional or more polyhydroxy compound in the diol component in an amount of about 5 mol% or less. That is, ethylene glycol, propylene glycol, glycerin, bentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or etherified polyhydroxyl compounds thereof.

In the present invention, the polyol component and the polyvalent carboxylic acid component are usually added in an amount of 180 to 250 in an inert gas atmosphere.
A polyester resin can be prepared by polycondensation at a temperature of ° C.

The amount of the fluorine-containing quaternary ammonium salt of the polarity controlling agent used in the present invention is 0.01 to 7% by weight, preferably 0.1 to 5% by weight, based on the binder resin. Examples of the fluorine-containing quaternary ammonium salt represented by the general formula (III) used in the toner of the present invention include the compounds shown in Table 1.

[0022]

Table 1 Specific examples of general formula (III) (1) Concrete example No. Structure type

[0023]

[Table 2] Table 2 Specific examples of general formula (III) (2) Specific examples No.

As the metal-containing monoazo dye contained in the toner of the present invention, chromium-containing monoazo dye, cobalt-containing monoazo dye and iron-containing azo dye are particularly preferable. Resin for binding 10
The amount used relative to 0 part is preferably 0.5 to 10 parts, more preferably 1 to 7 parts. As the styrene / acrylic resin contained in the toner of the present invention, a styrene / acrylic copolymer which has been conventionally used can be used, but among them, a styrene / diethylhexyl acrylate / normal butyl methacrylate copolymer is particularly preferable. The amount used is preferably 5 to 35 parts with respect to 100 parts of the binder resin, and particularly preferably 10 to 25 parts. Less than 5 copies is sufficient Q /
If the M level cannot be ensured and the amount of 36 copies or more, the lower limit fixing temperature becomes high, and there arises a problem that the PVC mat fusion resistance becomes poor.

The colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6
Any conventionally known dye or pigment such as G, lake, chalco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dye, monoazo dye, disazo dye, and dye may be used alone or in combination. . The amount of these colorants used is usually 1 to 30% by weight, preferably 3 to 20% by weight, based on the binder resin.
Is.

The toner of the present invention may further contain a magnetic material to be used as a magnetic toner. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, or aluminum of these metals, cobalt, copper, lead, magnesium, tin, and zinc. , Antimony, beryllium, bismuth, cadmium, calcium,
Examples thereof include alloys of metals such as manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These ferromagnetic materials have an average particle size of 0.1 to 2 μm.
It is desirable that the amount is about 20 to 200 parts by weight based on 100 parts by weight of the resin component, and particularly preferably 40 to 150 parts by weight based on 100 parts by weight of the resin component.

Further, the toner of the present invention may be mixed with additives as required. Examples of the additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidity imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black, tin oxide. And a fixing aid such as a low molecular weight polyolefin.

Further, when the toner of the present invention is used as a two-component developer, it is used as a mixture with carrier powder.

Further, according to the present invention, by coating the surface of the core particles with the silicone resin containing the conductive fine powder, the advantages of the conventional silicone resin-coated carrier can be maintained and the carrier can be made electrically conductive. By giving the charge, the phenomenon of charge accumulation in the carrier is effectively suppressed.

The carrier core particles coated with the silicone resin in the present invention may be those conventionally known, for example, ferromagnetic metals such as iron, cobalt and nickel, alloys and compounds such as magnetite, hematite and ferrite, and glass beads. And so on. The average particle size of these core particles is usually 10 to 1000 μm, preferably 30 to 500 μm.
Is. The amount of silicone resin used is usually 1 to 10% by weight based on the carrier core particles.

The silicone resin used in the present invention may be any conventionally known silicone resin, for example, commercially available KR261, KR271, KR272, KR27 manufactured by Shin-Etsu Silicone Co., Ltd.
5, KR280, KR282, KR285, KR25
1, KR155, KR220, KR201, KR20
4, KR205, KR206, SA-4, ES100
1, ES1001N, ES1002T, KR3093
And SR2100 and SR210 manufactured by Toray Silicone Co., Ltd.
1, SR2107, SR211O, SR2108, SR
2109, SR2115, SR2400, SR241
0, SR2411, SH805, SH806A, SH8
40 or the like is used. As a method of forming the silicone resin layer, the silicone resin may be applied to the surface of the carrier core particles by a method such as a spraying method or a dipping method as in the conventional method. The coating layer composition is prepared by adding conductive fine powder to a silicone resin solution and dispersing it with a mixer.

The fine powder dispersed in the coating layer is 0.01 to 5.0.
Particles having a particle size of about μm are preferable, and 2 to 30 parts by weight is preferably added to 100 parts by weight of the silicone resin, and 5 to 20 parts by weight is particularly optimum. Carbon black is most preferable as the conductive fine powder. The carbon black may be any conventionally known one, and examples thereof include contact black, furnace black, and thermal black.

[0033]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts are parts by weight. Polyester Resin Production Example 1 Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 700 parts Fumaric acid 130 parts n-Dodecenyl succinic anhydride 53.4 parts Hydroxine 0.1 parts were placed in a glass flask. The temperature was raised to 230 ° C. in an electric heating mantle, and the reaction was performed while stirring in a nitrogen stream. The acid value when the water generated by the reaction stopped flowing out was 1.5. Further, 63.5 parts of trimellitic anhydride was added and reacted for about 8 hours, and when the acid value reached 20, the reaction was terminated. The softening point of the obtained resin was 120 ° C.

Polyester Resin Production Example 2 Polyoxypropylene (2) -2,2-bis (4-hydroxyphenyl) propane 650 parts Fumaric acid 120 parts Isododecenyl succinic acid 53.4 parts 220 ° C. as in Polyester Resin Production Example 1 It reacted with. Furthermore, the softening point of the resin obtained by adding 79.0 parts of trimellitic anhydride and reacting at 200 ° C was 120 ° C.

Polyester Resin Polyester Resin Production Example 3 Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 490 parts terephthalic acid 188 parts n-dodecenyl succinic anhydride 26.8 parts diisopropyl orthotitanate 0.8 195 parts of polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane were reacted at 230 ° C. for about 5 hours in the same manner as in Polyester Resin Production Example 1, and further 78.8 parts of trimellitic anhydride were added at 200 ° C. In addition,
The reaction was performed for about 4 hours, and further under reduced pressure for 2 hours. The resin had a softening point of 115 ° C. and an acid value of 33.

Polyester Resin Production Comparative Example 1 Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 490 parts Terephthalic acid 204.3 parts Diisopropyl orthotitanate 0.8 parts Polyoxyethylene (2) -2 195 parts of 2-bis (4-hydroxyphenyl) propane were reacted at 230 ° C. for about 5 hours in the same manner as in Polyester Resin Production Example 1, and 78.8 parts of trimellitic anhydride were added at 200 ° C. and reacted for about 4 hours. The reaction was performed under reduced pressure for 2 hours. The resin had a softening point of 115 ° C. and an acid value of 34.

Next, a production example of a carrier having several silicone resins in the coating layer will be shown. This can be done by known means.

Carrier Production Examples 1 and 2 The components shown in the following Table 3 were mixed with 100 parts of toluene and dispersed with a homomixer for 30 minutes to prepare a coating layer forming liquid. This coating layer forming liquid was used as a spherical ferrite 1000 with an average particle size of 100 μm.
Carriers A and B having coating layers formed on the surface of parts by weight using a fluidized bed type coating device were obtained.

[0039]

[Table 3]

Example 1 Polyester resin production example 1 100 parts Carbon black (Mitsubishi Carbon Co. # 44) 12 parts Fluorine-containing quaternary ammonium salt compound Specific example No. 1 3 parts The mixture having the above composition was sufficiently stirred in a Henschel mixer. After mixing, the mixture was heated and melted by a roll mill at a temperature of 80 to 110 ° C. for about 40 minutes, cooled to room temperature, and the obtained kneaded product was pulverized and classified to obtain a toner of 5 to 20 μm. Next, this toner and 97 parts of a spherical ferrite carrier (hereinafter referred to as carrier C) having an average particle size of 100 μm without a coating layer were mixed in a ball mill to obtain a two-component developer. Next, set the developer in a plain paper copier (Ricoh FT-7030) equipped with a Teflon-coated roller as a fixing roller, and set the heat roller temperature to 1
When a continuous copy test was performed at 35 ° C, good images were obtained without causing offset or winding phenomenon.
No filming was found on the photoconductor or the developing sleep. In addition, when a hot offset, a cold offset, a winding occurrence temperature and a fixing lower limit temperature were measured as a fixing test, good results were obtained as shown in Table 4 below. Furthermore, when the Q / M was measured by a blower at 20 ° C. and 60% normal temperature and normal humidity, a satisfactory value of 15.4 μC / g was shown. Furthermore, when images were displayed in the environments of 30 ° C 90% and 10 ° C 15%, and the charge amount was measured, good results of 17.9 μC / g and 14.1 μC / g were obtained. was gotten. Further, when the state of spent of the carrier by the toner was observed after 100,000 sheets, no spent of the carrier by the toner was observed.

Comparative Example 1 Fluorine-containing quaternary ammonium salt compound N used in Example 1
A developer was obtained in the same manner as in Example 1 except that a salicylic acid derivative zinc salt was used in place of o.1, and an image test was conducted. As a result, there were no problems in low-temperature fixing property, offset resistance, and wrapping resistance. However, the Q / M at 10 ° C. 15% and 30 ° C. 90% was 15.7 μC / g and 4.3 μC / g, respectively, which showed a large difference in environmental fluctuation rate, which was a non-practical level.

Example 2 Polyester resin production example 2 100 parts Carbon black (Mitsubishi Carbon Co. # 44) 9 parts Fluorine-containing quaternary ammonium salt compound No. 1 0.5 part Cobalt-containing monoazo dye (T-77) 2 parts The above composition In the same manner as in Example 1, after thoroughly stirring and mixing the mixture in Example 1, in a Henschel mixer, 80-110 ° C with a roll mill.
After heating and melting at the temperature of about 40 minutes and cooling to room temperature, the obtained kneaded product was pulverized and classified to obtain a toner of 5 to 20 μm. A ball mill was mixed with 3.5 parts of this toner and 96.5 parts of carrier C to obtain a two-component developer. When a continuous copy test was conducted in the same manner as in Example 1 using this developer, good results were obtained as in Example 1. Also, this fixing property, offset resistance, wrapping resistance, and Q / M
The environmental change was good as shown in Table 4 below.

Example 3 Styrene / ethylhexyl acrylate / normal butyl methacrylate copolymer 15 parts Polyester Resin Production Example 3 A developer was obtained in the same manner as in Example 1 except that 80 parts were used. Next, this developer was applied in the same manner as in Example 1 at 30 ° C. 90
% And 10 ° C 15% respectively, images were taken out and the amount of charge was measured to be 17.8 μC / g, 24.2 μC / g
When the continuous copy test was further conducted, good results were obtained as in the case of Example 1. The fixability of this product was good as shown in Table 4 below. Further, when 10,000 images were printed, there was no nurse spent and it was a good image.

Comparative Example 2 A polyester resin of Production Comparative Example 1 was used in place of the polyester resin of Example 1 to prepare a developer in the same manner as in Example 2, and a continuous copy test was conducted. And Q / M environmental change were satisfactory results, but low temperature fixability was inferior and was outside the practical range. Comparative Example 3 A developer was prepared in the same manner as in Example 2 except that the fluorine-containing quaternary ammonium salt of Example 1 was not used, and a continuous copy test was conducted. As a result, low-temperature fixability, offset resistance, and winding resistance were found. Good, but Q / 15% at 10 ℃, 90% at 30 ℃
M was 23.3 μC / g and 6.1 μC / g, respectively, and the Q / M environmental fluctuations were large and out of the practical range.

Example 4 Chromium-containing monoazo dye (S-34) 3 parts A developer was obtained in the same manner as in Example 3 except that 10 parts of fluorine-containing quaternary ammonium salt No. 7 was used. When a continuous copy test was performed on this phenomenon agent in the same manner as in Example 1, the environmental fluctuation rate was good as in Example 1, and the fixability of this was good as shown in Table 4 below. It was

Example 5 A continuous copy test was conducted using the same compound as in Example 3 except that the developer was obtained by using Carrier C using Fluorine-containing quaternary ammonium salt Example-10. 1
Good Q / M environmental stability was obtained as well. The low temperature fixability, anti-offset property and anti-wrapping property of this product were good as shown in Table 4 below.

Example 6 A continuous copy test was conducted in the same manner as in Example 1 except that a carrier B was used to obtain a developer using Fluorine-containing quaternary ammonium salt compound Example-12. 1
Good Q / M environmental stability was obtained as well. The low temperature fixability, anti-offset property and anti-wrapping property of this product were good as shown in Table 4 below.

Comparative Example 4 A developer was prepared in the same manner as in Example 3 except that a rhodamine dye was used instead of the fluorine-containing quaternary ammonium salt compound Example-7 of Example 3, and a continuous copy test was conducted. As in Example 2, the low-temperature fixability, offset resistance, and wrapping resistance were satisfactory, but 10 ° C 15%, 30 ° C 90%
Q / M at 24.3μC / g, 8.1μC / g and Q / M
M Environmental change was large, and good images were not obtained. Further, when 1000 images were printed, toner spent on the carrier was generated, and the image was at a non-practical level.

Comparative Example 5 Styrene / diethylhexyl acrylate of Example 4 /
The same procedure as in Example 1 was carried out except that the normal butyl methacrylate copolymer was not used, but the environmental change was large and the Q / M was as low as 8.5 μC / g, which was not a practical level.

[0050]

[Table 4] Table 4 ○: Good ×: Poor △: Not practical

Offset generation temperature: An operation of fixing the toner image transferred on the copy paper under the conditions of a roller nip width of 4 mm and a linear velocity of 250 mm / sec while sequentially increasing the roller heating temperature by the Teflon-coated roller. The temperature at which scumming occurs is repeatedly obtained, and the minimum temperature at this time is set as the cold offset generation temperature, and the maximum temperature is set as the hot offset generation temperature.

Winding temperature: A so-called solid black original is used to transfer toner onto almost the entire surface of the copy paper,
The procedure of fixing is repeated in the same manner as in the measurement of the offset generation temperature except that the heating temperature of the roller is sequentially decreased, and the temperature when the copy paper is wound around the roller is obtained.

Lower limit fixing temperature: Fixing is performed in the same manner as in the case of measuring the offset generation temperature, and the temperature at which the toner fixing rate by the clock meter reaches 70% is obtained.

Lower limit temperature of environment: The charge amount is measured under the environment of 30 ° C. 90% and 10 ° C. 15%, and the variation rate thereof is obtained.

Charge level: The charge amount in an environment of 20 ° C. and 60% is calculated.

[0056]

EFFECTS OF THE INVENTION The dry developer of the present invention is (1) has sufficient offset resistance and wrapping resistance, and (2) can be fixed at a low temperature by the above-described method, and thus can be fixed at a high speed.
(3) It has a sufficient amount of charge and Q / M when the environment changes.
An excellent developer can be obtained because of little variation.

Claims (3)

[Claims] 1. In an electrophotographic toner containing a binder resin, a colorant and a polarity control agent as main components, the binder resin component of the toner is a diol component represented by the following general formula (I) and a divalent or higher valent component. 1 to 50 mol% of divalent carboxylic acid represented by the following general formula (II) or its anhydride in a compound selected from the group consisting of polyvalent carboxylic acid or its anhydride and its lower alkyl ester, and trimetic acid. Alternatively, a fluorine-containing quaternary ammonium salt containing a polyester resin obtained by condensation polymerization with an acid component containing 10 to 30 mol% of its anhydride and represented by the following general formula (III) as a polarity control agent component An electrophotographic toner comprising a compound. [Chemical 1] [Chemical 2] [Chemical 3] 2. The electrophotographic toner according to claim 1, further comprising a metal-containing azo dye as the polarity control agent component. 3. The toner for electrophotography according to claim 1, further comprising a styrene / acrylic copolymer resin as a binder resin component for the toner.