JP2002131969A - Electrostatic charge image developing color toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing color toner which effectively prevents a low temperature offset and a high temperature offset even when the toner is used for a fixing device with a decreased application amount of oil and which shows excellent light-transmitting property for an OHP and fixing efficiency. SOLUTION: The electrostatic charge image developing color toner consists of at least a binder resin and coloring agent. The storage elastic modulus (G'90) of the toner at 90 deg.C is <=6×104 Pa and the storage elastic modulus (G'140) at 140 deg.C is >=5×102 Pa. When the ratio of the storage elastic modulus (G') to the loss elastic modulus (G") is represented by tan δ=G"/G', the maximum of δ is present within the range from 90 to 120 deg.C and the maximum of δ is >=60 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color toner for developing an electrostatic image.

[0002]

2. Description of the Related Art In an electrophotographic process, a latent image is electrostatically formed on a photoreceptor using a photoconductive substance by various means, and the latent image is developed using toner to form a latent image on the photoreceptor. After the toner image is transferred to a transfer target such as paper with or without an intermediate transfer member, the fixed image is fixed to a transfer target such as paper by a plurality of steps. It is common to form. In recent years, with the development of equipment in the information-oriented society and the enhancement of communication networks, the electrophotographic process has been widely used not only for copiers but also for printers.
High reliability is increasingly demanded.

In particular, in the case of color electrophotography, it is required that an image to be formed has high image quality and high coloring. In order to obtain a high quality and high color image, the toner must be sufficiently melted and the image surface after fixing must be smooth from the viewpoint of translucency (especially, OHP translucency) and gloss. . For this reason, the fixing step in the electrophotographic process is particularly important.

[0004] As a contact-type fixing method generally used as a fixing method in the past, a method using heat and pressure at the time of fixing (hereinafter, referred to as "thermocompression bonding method") is general.
In the case of this thermocompression bonding method, since the surface of the fixing member and the toner image on the transfer-receiving member come into contact with each other under pressure, the heat efficiency is extremely good and the fixing can be performed quickly. It is known to be very effective. However, in the case of the above-mentioned thermocompression bonding method, the toner image is brought into pressure contact with the surface of the fixing member in a state of being heated and melted. A phenomenon (high-temperature offset) of transferring to a part other than the part occurred, which was a problem. In particular, in color toner fixing, since it is necessary to melt and mix a plurality of color toners, compared with black and white toner fixing, sufficient heat and pressure must be applied to the toner to make it flow more. Since it is necessary to release a thick toner layer in which a plurality of colors are superimposed without causing high-temperature offset, it is more difficult to release a toner image from a fixing member in color toner fixing than in black and white toner fixing. there were.

Therefore, as a simple method for preventing the toner from adhering to the surface of the fixing member, coating the surface of the fixing member with silicone oil or the like as an anti-offset liquid has been performed. However, when forming a color image, a relatively large amount of oil is required to prevent high-temperature offset by using only oil, so that adhesion of the oil to a transfer-receiving body and an image after fixing has been a problem.
Further, when oil is used, a tank for storing oil or the like is required in the fixing device, which makes it difficult to reduce the size of the device, replenishes the oil, and restricts cost reduction. Was.

Japanese Patent Application Laid-Open No. 56-158340 discloses a black-and-white toner exhibiting excellent oil-less fixing suitability due to the effect of a resin having a wide molecular weight distribution and a wax containing a low molecular weight component and a high molecular weight component. It has been disclosed. In this technique, the toner image on the transfer object is fixed on the transfer object by rubber elasticity due to a high molecular weight component to prevent high-temperature offset. However, when this technique is applied to fix a color image, the glossiness of the obtained fixed image decreases, and the color developability of the color image decreases, which has been a problem. In addition, since the color image sometimes overlaps three or four toner layers, the above-mentioned problem of the high-temperature offset could not be completely solved.

JP-A-63-174061, JP-A-63-174062
JP-A-63-174063 discloses a resin using an isocyanate, a resin containing an atomic group -NHCO- in the molecule, and a crystalline resin having a low molecular weight and a high cohesive energy in the form of an amide wax. Techniques are disclosed.
According to such a technique, low-temperature fixing can be achieved, but the offset resistance is insufficient. Although the molten toner permeates the paper, it has the effect of preventing offset, but a high-density image could not be obtained uniformly.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and even when applied to a fixing device having a reduced oil application amount, a fixing device which effectively prevents low-temperature offset and high-temperature offset. An object of the present invention is to provide a color toner for developing an electrostatic image with excellent efficiency.

According to the present invention, the fixing temperature range in which neither low-temperature offset nor high-temperature offset occurs is relatively wide,
Another object of the present invention is to provide a color toner for developing an electrostatic charge image having a relatively low temperature level and excellent fixing efficiency.

[0010]

The present invention comprises at least a binder resin and a colorant, has a storage elastic modulus (G _'90 ) at 90 ° C. of 6 × 10 ⁴ Pa or less and a storage elastic modulus (G at 90 ° C.). ' ₁₄₀ ) is 5 × 10 ² Pa or more, and the maximum value of δ when the storage modulus (G ′) and the loss modulus (G ″) are represented by tan δ = G ″ / G ′ is 90 to The present invention relates to a color toner for developing an electrostatic image, which is present at 120 ° C. and has a maximum value of δ of 60 ° or more.

The inventors of the present invention pay attention to the behavior of the toner in a specific temperature range, and increase the elasticity of the toner at the time of melting the toner (at the time of fixing) and decrease the elasticity of the toner at a relatively low temperature. Has been found to be able to achieve.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The color toner of the present invention has a storage elastic modulus (G _'90 ) at 90 ° C. of 6 × 10 ⁴ Pa or less, preferably 3 × 10 ⁴ Pa or less.
× 10 ^{4 to} 6 × 10 ⁴ Pa, more preferably 4 × 10 ^{4 to} 6 × 10 ⁴ Pa,
It is more preferably 5 × 10 ^{4 to} 6 × 10 ⁴ Pa, and the storage elastic modulus (G ′ ₁₄₀ ) at 140 ° C. is 5 × 10 ² Pa or more, preferably 5 × 10 ² Pa or more.
× 10 ² to 1 × 10 ⁵ Pa, more preferably 5 × 10 ² to 1 × 10 ⁴ Pa,
More preferably, it is 5 × 10 ² to 1 × 10 ³ Pa.

The storage elastic modulus (G ') is one index indicating the behavior characteristics of a substance, and a larger value means that the substance (toner) has a stronger tendency to behave elastically.
In the present specification, G ′ is a value measured under the following conditions by a viscoelasticity measuring device (rheometer (stress control type); manufactured by Rheological).・ Measurement jig; 20mm diameter parallel plate ・ Measurement frequency: 0.1Hz ・ Measurement strain: Max5% ・ Measurement temperature: 60-180 ℃ ・ Measurement heating rate: 2 ℃ / min. ・ Gap: 1mm

[0014] G _'90 is more than 6 × 10 ⁴ Pa, not excellent low-temperature fixing to the elasticity of the toner is strong, easy to low-temperature offset occurs. Therefore, it is necessary to set the fixing temperature to be relatively high, and a relatively large amount of energy is required for fixing, so that the running cost is deteriorated). G ' ₁₄₀ is 5
When the pressure is less than × 10 ² Pa, high-temperature offset is likely to occur due to low elasticity of the toner.

In the toner of the present invention, the storage elastic modulus (G ′) and the loss elastic modulus (G ″) of the toner are represented by tan δ = G ″ / G ′, δ (vertical axis) −temperature ( In the graph on the horizontal axis), δ has a specific maximum value. Referring to FIG. 1 showing a graph of δ (vertical axis) -temperature (horizontal axis) of an example of the toner of the present invention, the toner of the present invention has a maximum value of δ of 90 to 120 in the above graph. ° C, preferably 90-110 ° C,
More preferably, it exists at 95 to 105 ° C., and the maximum value of δ is 60
° or more, preferably 60 ° or more and less than 90 °, more preferably
It is 60 to 85 °, more preferably 60 to 80 °.

Tan δ is one index indicating the behavioral characteristics of a substance. As δ is smaller, tan δ is smaller, meaning that the substance (toner) has a stronger tendency to behave elastically, while δ is larger. The larger the tan δ, the greater the tendency of the substance (toner) to viscously behave. The presence of the maximum value of δ means that the viscoelasticity of the substance (toner) rapidly changes before and after the temperature at which the maximum value is shown (hereinafter, referred to as the maximum temperature). Means that the tendency of the substance to behave viscously as a whole increases, whereas the tendency changes completely at the maximum temperature, and that after the maximum temperature, the tendency of the substance to behave elastically as a whole increases. .

When the maximum value of δ is less than 90 ° C., the elasticity of the toner is increased even at a low temperature, so that low-temperature fixing is not excellent.
Low-temperature offset is likely to occur. On the other hand, the maximum value of δ is 120
When the temperature exceeds ℃, the elasticity of the toner hardly increases at the time of fixing, so that high-temperature offset easily occurs and the fixing temperature width is narrowed. When the maximum value of δ is less than 60 °,
Since the viscosity of the toner is not sufficiently increased at the time of fixing, low-temperature offset tends to occur.

The graph of δ (vertical axis) -temperature (horizontal axis) is as described above.
It can be measured by a method similar to the method of measuring G '.

The toner of the present invention may be composed of any toner component as long as the above-mentioned viscoelasticity can be obtained, and may be produced by any known method. And by using the manufacturing method.

The toner of the present invention contains at least a binder resin and a colorant, and optionally contains a charge control agent, a release agent, magnetic particles, inorganic fine particles, organic fine particles, a grinding aid, and a wax dispersant.

The binder resin used in the toner of the present invention is:
There is no particular limitation, and a synthetic resin or a natural resin known in the field of toner can be used. Specific examples thereof include, for example, polyester resin, styrene resin, acrylic resin, styrene-acryl resin, silicone resin,
Epoxy resin, diene resin, phenol resin, terpene resin, coumarin resin, amide resin, amide imide resin, butyral resin, urethane resin, ethylene-vinyl acetate resin, petroleum resin, polycarbonate resin, polyether Resin, polyacrylonitrile resin,
Examples thereof include polyacrylate resins and the like, which can be used alone or in combination. It is preferable to use a polyester resin from the viewpoint of fixability.

When any of the above binder resins is used, the viscoelasticity of the toner can be controlled by adjusting the amount of the crystalline resin used alone or in combination with the amorphous resin. . That is, when the amount of the crystalline resin is increased, G ′ ₁₄₀ generally increases, and the maximum value of δ also increases. On the other hand, when the amount of the crystalline resin is reduced, G ′ ₁₄₀ generally decreases, and the maximum value of δ also decreases.

A crystalline resin is a resin that can be crystallized by an increase in temperature. Here, crystallization means that when the temperature of the resin is raised, the degree of freedom of the polymer chains constituting the resin increases, and at least a part of the polymer chains is arranged so as to have a certain degree of regularity in three dimensions. Has been reorganized and the resin G '
Is a phenomenon that increases. It is known that such a crystallization is more likely to occur as the heating rate is lower, but in the present invention, it is sufficient that the crystallization occurs at a heating rate of 2 ° C./min. Since G ′ of the crystalline resin increases due to the crystallization, it is considered that the viscoelasticity of the toner can be controlled by increasing or decreasing the amount of the crystalline resin. The crystalline resin may or may not have a crystalline phase in the toner as long as the crystallization can occur, but preferably has a crystalline phase. The crystal phase refers to a phase in which all or a part of the polymer chains are gathered to form a three-dimensionally ordered crystal lattice. This is because it easily occurs. On the other hand, the amorphous resin refers to a resin that does not cause the above-described crystallization even when the temperature is increased.

For example, when a crystalline polyester resin and an amorphous polyester resin are used as the binder resin, the crystalline polyester resin includes at least a monomer that easily causes crystallization (hereinafter, simply referred to as a “crystalline monomer”),
That is, the carboxylic acid component and / or the alcohol component including the crystalline alcohol component and / or the crystalline carboxylic acid component is polymerized by a known method. Specifically, in the presence of a polymerization initiator, the mixture is heated with stirring under a nitrogen atmosphere. Can be obtained by: The amount of the crystalline monomer with respect to the total amount of the monomer is not particularly limited as long as the obtained resin can cause the above-mentioned crystallization.
It is desirably 10 to 60 mol%, preferably 10 to 40 mol%. The acid value of the crystalline polyester resin is preferably adjusted to 0 to 35 KOH mg / g, and more preferably 0 to 15 KOH mg / g, from the viewpoint of environmental friendliness.

The crystalline monomer is not particularly limited as long as it is a divalent monomer having a linear structure to such an extent that crystallization can occur at a polymer chain site containing the monomer. As the crystalline monomer (crystalline alcohol component and crystalline carboxylic acid component), for example, the reactive groups at both ends are selected from the group consisting of an alkylene group having no substituent and a divalent cyclic saturated hydrocarbon group. Monomers linked by one or more groups are included.

Preferred crystalline alcohol components include, for example, compounds represented by the general formulas (1) and (2).

[0027]

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In the formula (1), R ¹ has 1 to 8 carbon atoms, preferably
2 to 6 alkylene groups. Such compounds are preferably ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,
6-hexanediol and the like are preferable, and ethylene glycol is more preferable.

In the formula (2), m and p are each independently an integer of 0 to 5, preferably 0 to 2. Such compounds are preferably 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, and 1,4-dihydroxycyclohexane, and more preferably 1,4-cyclohexanedimethanol.

Preferred crystalline carboxylic acid components include, for example, compounds represented by the general formulas (3) to (4) and anhydrides or lower alkyl esters of these acids.

[0031]

Embedded image

In the formula (3), R ² has 1 to 8 carbon atoms, preferably 2 carbon atoms.
To 6 alkylene groups. Preferred as such compounds are malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid.

In the formula (4), q and r are each independently an integer of 0 to 5, preferably 0 to 2. As such a compound, preferably 1,4-cyclohexanedicarboxylic acid,
1,4-bis (carboxymethyl) cyclohexane and 1,4-bis (2-carboxyethyl) cyclohexane, more preferably 1,4-cyclohexanedicarboxylic acid.

As monomers other than the above-mentioned crystalline monomers capable of constituting the crystalline polyester resin (hereinafter, referred to as amorphous monomers), the following divalent or higher-valent amorphous alcohol components and amorphous carboxylic acid components are used. Can be done.

Examples of the divalent amorphous alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (3,3)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl)
Propane, bisphenol A alkylene oxide adducts such as polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, 1,2-propanediol, neopentyl glycol, 1,4-butenediol, Examples include dihydric alcohol components such as bisphenol A and hydrogenated bisphenol A.

Examples of the trihydric or higher amorphous alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1.4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane,
Trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like.

The divalent amorphous carboxylic acid component includes, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, n-dodecenylsuccinic acid, isodode Cenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, isooctenylsuccinic acid, n-octylsuccinic acid, and isooctylsuccinic acid, and anhydrides or lower alkyl esters of these acids. No.

Examples of the trivalent or higher-valent amorphous carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, and 2,5,7-naphthalene. Tricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-
2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, and empol trimer acid, and the like. Examples thereof include acid anhydrides and lower alkyl esters.

The amount of the crystalline polyester resin as described above is not particularly limited as long as the toner of the present invention is obtained, but is usually 10% by weight or more, preferably 30% by weight of the total amount of the binder resin.
% By weight or more is desirable.

The amorphous polyester resin is obtained by polymerizing a carboxylic acid component and an alcohol component containing no crystalline monomer, that is, the above-mentioned divalent or higher valent amorphous carboxylic acid component and amorphous alcohol component according to a known method. Obtainable.

From the viewpoint of not causing a decrease in elasticity at higher temperatures, the amorphous polyester resin preferably has a crosslinked structure. Having a crosslinked structure means that two or more linear polymers have a three-dimensional network structure in which specific atoms (crosslinking points) are chemically linked. Amorphous polyester resin having such a crosslinked structure, as a monomer, among the above-mentioned divalent or higher-valent amorphous carboxylic acid component and amorphous alcohol component, at least a trivalent or higher amorphous carboxylic acid component and It can be obtained by using an amorphous alcohol component and / or a divalent or higher-valent amorphous carboxylic acid component having a polymerizable double bond and / or an amorphous alcohol component. The total amount of the amorphous carboxylic acid component and the amorphous alcohol component used as the crosslinking agent is 10 to 60 mol%, preferably 30 to 45 mol%, based on the total amount of the monomers constituting the amorphous polyester resin. desirable.

The acid value of the amorphous polyester resin is preferably adjusted to 0 to 35 KOH mg / g, more preferably 0 to 15 KOH mg / g, from the viewpoint of environmental friendliness.

From the viewpoints of heat resistance and fixability, crystalline resins are
Glass transition point (Tg) 50-70 ° C, preferably 55-65 ° C,
It is desirable that the softening point (Tm) is 80 to 150 ° C, preferably 90 to 120 ° C. Further, the amorphous resin has a Tg of 50 from the viewpoint of improving heat resistance and not impairing the elasticity of the crystalline resin.
It is desirable that the Tm is 110 to 150 ° C, preferably 120 to 140 ° C. In this specification, Tg, Tm, Mn, and Mw / Mn of the amorphous resin are values measured using a component soluble in tetrahydrofuran in the amorphous resin.

In the present invention, the viscoelasticity of the toner can also be controlled by adjusting the composition, Tg, Tm, and Mw / Mn of the crystalline resin and the amorphous resin. For example, G ′ ₁₄₀ can be increased by increasing the amount of the crystalline monomer in the crystalline resin and decreasing the amount of the crosslinking agent in the amorphous resin. At this time, if Mw / Mn of the crystalline resin is further reduced,
Increase of G _'140 becomes remarkable. It is possible to reduce the G _'90 by lowering the Tg of the crystalline resin and / or non-crystalline resin. Further, by increasing the Tg of the crystalline resin, it can be increased G _'90. In addition, Tm
As the crystallinity is increased, the crystallinity is easily damaged. By increasing the Mw of the crystalline resin and / or the amorphous resin, the maximum value of δ can be shifted to a higher temperature side. The maximum value of δ can be increased by reducing the Mw / Mn of the crystalline resin and / or the amorphous resin.

As the coloring agent, known pigments and dyes can be used. For example, various carbon black, activated carbon,
Titanium black, aniline blue, calcoil blue,
Chrome Yellow, Ultramarine Blue, Dupont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Copper Phthalocyanine, Malachite Green Oxalate, Lamp Black, Rose Bengal, CI Pigment Red 48: 1, CI Pigment Red 57: 1, CI Pigment Red 122, CI Pigment Red 184, C.
I. Pigment Yellow 12, CI Pigment Yellow
17, CI Pigment Yellow 93, CI Pigment Yellow 97, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 155, CI
Pigment Yellow 180, CI Pigment Yellow 1
85, CI Solvent Yellow 162, CI Pigment
Blue 15: 1, CI Pigment Blue 15: 3, and the like. The addition amount of the colorant is preferably 2 to 10 parts by weight based on 100 parts by weight of the binder resin.

In the black toner, a part or all of the colorant can be replaced with a magnetic substance. Known magnetic particles such as ferrite, magnetite, and iron can be used as such a magnetic material. The average particle size of the magnetic particles is preferably 1 μm or less, particularly preferably 0.5 μm or less, from the viewpoint of obtaining dispersibility during the production. When magnetic particles are added from the viewpoint of preventing scattering while giving the properties as a non-magnetic toner, the addition amount is 0.5 to 10 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the binder resin.
5 to 8 parts by weight, more preferably 1 to 5 parts by weight is desirable. If the amount exceeds 10 parts by weight, the developer carrier for the toner
The magnetic restraining force of the (built-in magnet roller) becomes strong, and the developability decreases.

In the present invention, the colorant and the magnetic substance may be used as a masterbatch obtained by previously mixing and melting and kneading with the binder resin to be used from the viewpoint of improving the dispersibility in the binder resin. preferable. The addition amount of the master batch is determined so that the ratio of the binder resin and the colorant in the toner falls within the above range.

As the charge control agent, known materials conventionally used as charge control agents for toners can be used. However, charge control agents for color toners have an adverse effect on the color tone and light transmittance of color toners. It is preferable to use a colorless, white or light-colored charge control agent that does not affect the color. As such a charge control agent, for example, a zinc or chromium metal complex of a salicylic acid derivative, a calixarene-based compound, an organic boron compound, a fluorinated quaternary ammonium salt-based compound, or the like is suitably used. Examples of the salicylic acid metal complex include, for example, JP-A-53-127726 and JP-A-62-14.
Nos. 5255 and the like, as calixarene-based compounds, for example, those described in JP-A-2-201378 and the like, and as organoboron compounds, for example, JP-A-2-221
No. 967 can be used.

As the release agent, known materials conventionally used as release agents for toners can be used. For example, polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, ester wax, Carnauba wax, sasol wax, rice wax, candelilla wax,
Jojoba oil wax, beeswax wax and the like. Among the release agents, from the viewpoint of releasing properties and claw marks from the fixing roller, smearing properties, etc., two or more waxes having different melting points, particularly a wax having a melting point of 60 to 120 ° C. and a melting point of 120 to 150.
It is preferable to use a wax having a melting point of 130 to 140 ° C and a melting point of 80 ° C.
Use a low melting wax at ~ 120 ° C. The addition amount of the release agent is preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin,
When two or more release agents are used, their total amount may be within the above range.

The toner of the present invention is prepared by, for example, mixing the above-mentioned materials with a mixer such as a Henschel mixer, melt-kneading them with a twin-screw extruder, and then cooling them. , If desired, and further by adding an external additive. It is preferable that the volume average particle diameter of the toner is controlled to 5 to 9 μm.

By adding an external additive, the fluidity and cleaning property of the toner can be improved. The external additive is not particularly limited as long as it is a material that has been conventionally used as an external additive in the field of toner, and examples thereof include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titania fine particles. Inorganic stearic acid compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, and inorganic titanate compound fine particles such as strontium titanate and zinc titanate can be used. These fine particles are desirably used after being surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, etc. from the viewpoint of environmental resistance and heat storage stability, and the added amount is based on 100 parts by weight of the toner. It is desirable to use 0.05 to 5 parts by weight, preferably 0.1 to 3 parts by weight. Two or more external additives may be used in combination, and in that case, the total amount thereof may be within the above range.

The toner of the present invention as described above can be applied to a fixing device in which the oil application amount is reduced to 8 × 10 ⁻⁴ mg / cm ² or less, preferably an oil-less fixing device, even if it is applied to a low-temperature offset and a high-temperature Offset can be effectively prevented, and an image excellent in OHP transmissivity with good fixing efficiency (running cost) can be provided. Therefore, the toner of the present invention is advantageous when designing a small and inexpensive copier or printer.

The above-mentioned fixing device to which the toner of the present invention can be effectively applied employs a known thermocompression bonding method using heat and pressure at the time of fixing, and the amount of applied oil is measured as follows. You. That is, a plain paper used in a general copying machine (typically, copying paper manufactured by Minolta, trade name "CF paper") is used on a fixing member coated with oil on its surface.
When passing through, oil adheres to plain paper. The oil on the plain paper is extracted using a Soxhlet extractor.
Hexane is used as the solvent. By quantifying the oil contained in this hexane with an atomic absorption spectrometer, the amount of oil adhering to plain paper can be quantified, and the oil application amount can be determined by dividing the value by the area of plain paper. Can be requested. If the oil application amount obtained in this way exceeds 8 × 10 ^-4 mg / cm ² , the image quality deteriorates due to the oil remaining on the image surface after fixing, especially when utilizing transmitted light such as OHP. OHP translucency deteriorates remarkably,
Problems arise, such as oil sticking to the transfer target and sticking. Further, when the amount of applied oil increases, the capacity of the tank for storing the oil also increases, which causes a problem that the size of the fixing device increases.

The oil applied to the fixing member is not particularly limited, but examples thereof include heat-resistant oils, and oils for preventing offset such as dimethyl silicone oil, fluorine oil, modified oils such as fluorosilicone oil and amino-modified silicone oil. Can be When the toner of the present invention is used, the amount of oil applied may be extremely small as described above, so that expensive fluorine oil, fluorosilicone oil or the like may be used.

The toner of the present invention has a relatively wide fixing temperature range (a fixing temperature range in which neither low-temperature offset nor high-temperature offset occurs) at a relatively low temperature level. Specifically, the fixing temperature range of the toner of the present invention is 40
℃ or more, preferably 50 ℃ or more, its temperature level,
In particular, the lower limit of the fixing temperature width is 135 ° C or less, preferably 130 ° C or less when applied to an oilless fixing device, and is applied to a fixing device having an oil application amount of 8.0 × 10 ⁻⁴ mg / cm ^2. In 1
20 ° C or less, preferably 115 ° C or less, more preferably 110 ° C
It is as follows. If the fixing temperature width is too high, the temperature of the fixing member (fixing temperature) decreases due to repeated contact between the transfer target body and the fixing member during fixing, particularly when image formation is performed twice or more continuously. In addition, in the second and subsequent image formations, fixing is not sufficiently performed, and a phenomenon (low-temperature offset) that the copied image is easily peeled is likely to occur. When the fixing temperature range is at a relatively high temperature level, a relatively large amount of energy is required for fixing, so that the running cost deteriorates. Hereinafter, the present invention will be described in more detail with reference to Examples, but it should not be construed that the invention is limited thereto.

[0056]

EXAMPLES (Production of PES 1 to 9) Each monomer was weighed so that the molar ratio of the monomers was as shown in Table 1, and these were put into a two-liter four-necked flask. A reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were attached, and nitrogen was introduced into the flask from the nitrogen gas inlet tube and stirred while heating with a mantle heater. To make it react. At this time, the reaction temperature was 180 to 240 ° C. During the reaction, the reaction state was traced while measuring the acid value. When the acid value reached a predetermined value, the reaction was terminated to obtain a polyester resin. When two or more resins were used in Examples and Comparative Examples, those resins were dry-blended with a Henschel mixer before use.

[0057]

[Table 1]

The abbreviations in the table indicate the following compounds. TPA; terephthalic acid IPA; isophthalic acid CHDA; cyclohexanedicarboxylic acid DSA; dodecenylsuccinic acid TMA; trimellitic acid FA; fumaric acid BPA-PO; bisphenol A propylene oxide 2 mol adduct BPA-EO; bisphenol A ethylene oxide 2 mol adduct EG; Ethylene glycol CHDM; Cyclohexane dimethanol TMP; Trimethylolpropane

[0059]

[Table 2]

(Pigment Masterbatch) Binder resin and CI Pigment Blue 15-
3 (Toyo Ink Manufacturing Co., Ltd.) and weight ratio (resin: pigment) 7: 3
In a pressure kneader, kneaded at 120 ° C. for 1 hour, cooled, and coarsely pulverized with a feather mill to obtain a pigment master batch.

(Example 1) 10 parts by weight of a pigment master batch, 93 parts by weight of a binder resin (PES1), 2 parts by weight of a high-melting-point polyprylene wax (100-TS; manufactured by Sanyo Chemical Industries, Ltd.), and a low-melting-point polyethylene wax ( 0.5 parts by weight (800P; manufactured by Mitsui Chemicals, Inc.) were mixed with a Henschel mixer, and the mixture was kneaded with a twin-screw extruder. Next, after cooling the kneaded material, the mixture was coarsely pulverized by a feather mill, further finely pulverized by a jet mill, and classified to obtain toner particles having an average particle diameter of 6 μm. 1.0 part by weight of silica (H2000; manufactured by Clariant Japan) was added to 100 parts by weight of the toner particles, and mixed with a Henschel mixer to obtain a toner.

(Examples 2 to 6 and Comparative Examples 1 to 7) Except that the binder resins shown in Table 3 were used, and that the pigment master batch prepared using the binder resins was used. In the same manner as in 1, a toner was obtained.

[0063] each of the examples and the viscoelastic properties of the toner obtained in Comparative Example _{(G '90, G' 140} , and [delta] (vertical axis) - Temperature (graph on the horizontal axis)) of the viscoelasticity measuring apparatus (rheometer It was measured using a meter (stress tech type; manufactured by Rheological). A graph of δ (vertical axis) -temperature (horizontal axis) of the toner obtained in Example 1 is shown in FIG.

[0064]

[Table 3]

(Evaluation) A developer obtained by mixing each toner and a carrier described below at a toner mixing ratio of 6% by weight was mounted on a full-color copying machine (CF900; manufactured by Minolta) having the following system configuration and evaluated. did. Recording agent; CF paper Toner adhesion amount: 12 g / m ² Fixer; Any of the following system 1 or system 2 can be selected.・ System 1: Adjusted oil application amount to 0 (none) (Contact type heat fixer containing fluororesin on the fixing member surface (Heat-compression bonding method)) ・ System 2: Adjust oil application amount in system 1 configuration
Adjusted to 8.0 × 10 ^-4 mg / cm ^{2 The} above toner adhesion amount indicates the toner adhesion amount when copying a solid image, and the toner is suctioned with air in an unfixed state, and the suctioned image area and This is a value calculated based on the sucked toner weight.

A solid image was copied by varying the fixing temperature, and a fixing temperature width at which neither a low-temperature offset nor a high-temperature offset occurred was determined, and evaluated according to the following ranking. The lower limit temperature is also shown. ◎: Fixing temperature range was 50 ° C. or higher; ○: Fixing temperature range was 40 ° C. or higher but lower than 50 ° C. (no problem in practical use); ×: Fixing temperature range was lower than 40 ° C. (practical level) Problematic).

The fixing lower limit temperature and the fixing upper limit temperature were determined as follows. -Fixing lower limit temperature The obtained solid image was folded into two from the center, and the peelability of the image was visually evaluated. The temperature between the fixing temperature when the image was peeled off and the lower limit of the fixing temperature at which the image was not peeled off was taken as the lower limit fixing temperature.・ Fixing upper limit temperature After copying a solid image, white paper (CF paper) was passed through and the high-temperature offset on the white paper was visually evaluated. The temperature between the fixing temperature when the high-temperature offset occurred and the upper limit fixing temperature at which the high-temperature offset did not occur was defined as the fixing upper limit temperature.

OHP translucency After outputting a gradation image having a maximum toner adhesion amount of 4 g / m ² , evaluation was made visually using an OHP projector. Recording material: OHP sheet for exclusive use of full color (manufactured by Minolta Co.) ；; well transmissive;

[0069]

[Table 4]

(Coated carrier) 500 ml capacity equipped with a stirrer, condenser, thermometer, nitrogen inlet tube and dropping device
Was charged with 100 parts by weight of methyl ethyl ketone. Under a nitrogen atmosphere at 80 ° C., methyl methacrylate 36.7 parts by weight, 2-hydroxyethyl methacrylate 5.1 parts by weight, 3
-Methacryloxypropyl tris (trimethylsiloxy)
A solution obtained by dissolving 58.2 parts by weight of silane and 1 part by weight of 1,1'-azobis (cyclohexane-1-carbonitrile) in 100 parts by weight of methyl ethyl ketone was dropped into the reactor over 2 hours and aged for 5 hours. Was. To the obtained resin, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.
(1%) was adjusted so that the OH / NCO molar ratio was 1/1, and then diluted with methyl ethyl ketone to prepare a coat resin solution having a solid ratio of 3% by weight. Fired ferrite powder F as core material
Using -300 (volume average particle size: 50 μm, manufactured by Powder Tech), the amount of the coating resin with respect to the core material was reduced with the above coating resin solution.
It was applied and dried with a spira coater (manufactured by Okada Seiko Co., Ltd.) to 1.5% by weight. The obtained carrier was calcined in a hot-air circulation oven at 160 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve shaker equipped with a 106 μm and 75 μm screen mesh to obtain a coated carrier.

(Measurement Method) In this specification, the value obtained according to the following method is used as the glass transition point (Tg) of the resin. Using a differential scanning calorimeter (DSC-200: manufactured by Seiko Denshi), precisely weigh 10 mg of the sample to be measured, put it in an aluminum pan, and use α-alumina in an aluminum pan as a reference. Heating rate 30 ° C
After raising the temperature from room temperature to 200 ° C. at a rate of 30 ° C./min, it is cooled and measured at a rate of 10 ° C./min between 30 ° C. and 120 ° C. The shoulder value of the main endothermic peak in the range is defined as Tg.

As the softening point (Tm) of the resin, a value obtained according to the following method is used. 1.0 g of the sample to be measured is weighed, and using a flow tester (CFT-500: manufactured by Shimadzu Corporation), using a die of h1.0 mm × φ1.0 mm, the temperature rising rate is 3.0 ° C.
/ min, preheating time 180 seconds, load 30kg, measurement temperature range 50-160
The measurement is performed under the condition of ° C., and the temperature at which the above sample flows out by 1/2 is defined as the resin softening point (Tm).

The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the resin are determined using values measured using gel permeation chromatography (GPC) (Type 830-RI, manufactured by JASCO Corporation). ing. See column 40
While maintaining the temperature at ° C., tetrahydrofuran is flowed at 1 ml / min as a carrier solvent, 30 mg of a sample to be measured is dissolved in 5 ml of tetrahydrofuran, 100 μl of this solution is introduced into the apparatus together with the above-mentioned carrier solvent, and the polystyrene equivalent is determined.

The acid value was determined by dissolving a 10 mg sample in 50 ml of toluene and titrating with a N / 10 potassium hydroxide / alcohol solution previously specified using a mixed indicator of 0.1% bromthymol blue and phenol red. , N / 10 potassium hydroxide / alcohol solution.

[0075]

The toner of the present invention can effectively prevent low-temperature offset and high-temperature offset even when applied to a fixing device with reduced oil application amount, and has excellent fixing efficiency and OHP translucency. Good image can be provided. The toner of the present invention has a relatively wide fixing temperature range at which neither low-temperature offset nor high-temperature offset occurs, and has a relatively low temperature level.

[Brief description of the drawings]

FIG. 1 is a graph showing the viscoelasticity of an example of the toner of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihiro Mikuri 2-13-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Masayuki Hagi Azuchi-cho, Chuo-ku, Osaka-shi, Osaka 2-3-13 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H005 AA01 AA21 CA08 DA06 EA03 EA07 EA10 2H033 AA02 AA09 AA11 AA32 BA46 BA58

Claims (3)

[Claims] 1. A storage elastic modulus (G _'90 ) at 90 ° C. of 6 × 10 ⁴ Pa or less, comprising at least a binder resin and a colorant.
The storage elastic modulus (G ′ ₁₄₀ ) at 140 ° C. is 5 × 10 ² Pa or more, and the storage elastic modulus (G ′) and the loss elastic modulus (G ″) are tanδ =
A color toner for developing an electrostatic image, wherein the maximum value of δ when represented by G ″ / G ′ exists at 90 to 120 ° C., and the maximum value of δ is 60 ° or more. 2. The color toner for developing electrostatic images according to claim 1, wherein the binder resin contains a crystalline resin, and the content of the resin is 30% by weight or more of the total amount of the binder resin. 3. The color toner for developing electrostatic images according to claim 1, which is suitable for a fixing device having an oil application amount of 8.0 × 10 ⁻⁴ mg / cm ² or less.