JPH06175394A - Color toner - Google Patents

Abstract

PURPOSE:To provide a color toner capable of forming a fixed image excellent in smoothness, not causing offsetting and having satisfactory developing property, transferability and cleanability. CONSTITUTION:This color toner contains a resin binder and a colorant. The resin binder is obtd. by a copolymn. reaction of a polymerizable mixture contg. a monomer represented by the formula and at least one kind of monomer selected among styrene type monomers and (meth)acrylate monomers. The resin binder contains 2-40mol% of the monomer represented by the formula. The softening point (Tsp) of the resin binder is 90 deg.C<=<Tsp<=115 deg.C and the glass transition temp. (Tg) is 50 deg.C(Tg<=65 deg.C. In the formula, R<1> is H or-CH3 and R<2> is 8-18C alkyl or alkenyl.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a color toner containing at least a binder resin and a colorant.

[0002]

2. Description of the Related Art In full-color copying, it is required to fix the image surface smoothly in order to satisfy the color reproducibility, the glossiness of the image and the light transmittance of the OHP transfer material. From such a viewpoint, the heating and pressure fixing process using a soft roller having a good followability with respect to the unevenness of the color toner on the surface of the unfixed image is preferable.

On the other hand, it is preferable that the color toner used for full-color copying has a smooth surface easily formed by a fixing process in a relatively low temperature range.

From this point of view, conventionally, as a binder resin of a toner for exhibiting a good low temperature fixing property,
It has been practiced to use a non-crosslinked polyester resin having a low molecular weight and a low softening point.

However, this non-crosslinked polyester resin is
Since the ester bond (polar group) is present in a high proportion in the main chain, it has the following problems. It has high wettability and adhesiveness with the fixing roller and easily causes hot offset phenomenon. The chemical affinity to the surface of the photoconductor becomes excessive,
Inferior in transferability and cleaning property. Since the negative charging property is high, excessive charging (charge-up) due to friction is likely to occur, and the electric adhesion to the surface of the photoconductor becomes excessive, resulting in poor transferability and cleaning property. Since it has a high affinity with water, the charging property has a large environmental dependency.

The problems described above are such that an electrostatic latent image for each color is formed on a photosensitive member by imagewise exposure, and toner of each color is superposed on the electrostatic latent image for development to form a color toner image. This is a particularly noticeable problem in a method of collectively transferring the superimposed color toner images onto a transfer member and heating and fixing the transferred toner images (hereinafter referred to as “collective transfer method”).

A technique for blocking a part of polar groups by using a polyester resin having a low acid value and a low hydroxyl value has been introduced (see Japanese Patent Laid-Open No. 163564/1993). Has not yet been resolved.

On the other hand, a technique of using a styrene-acrylic resin having a low molecular weight and a low softening point as a binder resin for toner is known (see Japanese Patent Laid-Open No. 2-135459). Since this styrene-acrylic resin does not have a polar group in its main chain, it is superior to the polyester resin in terms of offset resistance, transferability, and cleaning property.

However, a styrene-acrylic resin having a low molecular weight and a low softening point has a small intermolecular force, and therefore is very brittle and has a low hardness. Therefore, in the color toner made of such a binder resin, the toner particles are easily crushed by stirring in the developing device to generate fine powder. Further, external additive particles such as a fluidizing agent are likely to be embedded on the surface of the toner particles having low hardness. Since the fine particles generated by the crushing and the toner particles in which the external additive particles are buried have a large adhesive force to the carrier surface, the developability is deteriorated with time. Further, since the toner particles in which the fine powder and the external additive particles are buried have a large adhesive force to the surface of the photoconductor, the transferability and the cleaning property are deteriorated with time. This problem is particularly remarkable when applied to a batch transfer method, a non-contact development process, and a thin layer forming process.

[0010]

SUMMARY OF THE INVENTION The present invention has been made under the circumstances described above, and the first object of the present invention is to smooth the surface by a fixing process in a relatively low temperature range. Another object of the present invention is to provide a color toner capable of obtaining an excellent fixed image. A second object of the present invention is to provide a color toner in which a binder resin is less likely to wind around the heat roller in the fixing process by the heat roller and hot offset does not occur. A third object of the present invention is to combine a large strength (crush resistance) that is not crushed by a stress caused by stirring in a developing device and a high hardness that does not cause burial of an external additive and the like on the surface of a carrier or a photoreceptor. On the other hand, it is an object of the present invention to provide a color toner having an appropriate adhesive force and having good developability, transferability, and cleanability for a long period of time. A fourth object of the present invention is to
It is an object of the present invention to provide a color toner having a relatively low affinity with water and a small environmental dependence of charging. A fifth object of the present invention is to provide a color toner that is particularly suitable for use in a batch transfer method, a non-contact development process, a thin layer forming process, and an OPC process.

[0011]

The color toner of the present invention is a color toner containing at least a binder resin and a colorant, wherein the binder resin is a monomer represented by the following chemical formula 2 and a styrene-based monomer. Obtained by a copolymerization reaction of a polymerizable mixture containing at least one monomer selected from the group consisting of a monomer, an acrylic acid ester-based monomer and a methacrylic acid ester-based monomer. The ratio of the monomer represented by the following Chemical formula 2 is 2 to 40
%, And the softening point (Tsp) and glass transition point (Tg) of the binder resin are in the ranges represented by the following formulas. Formula) 90 ° C. ≦ Tsp ≦ 115 ° C. 50 ° C. <Tg ≦ 65 ° C.

[0012]

[Chemical 2] [In Chemical Formula 2, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted alkyl group or alkenyl group having 8 to 18 carbon atoms. ]

[0013]

[Action]

(1) Since the binder resin constituting the color toner is composed of a styrene- (meth) acrylate copolymer or a (meth) acrylate copolymer having a low molecular weight and a low softening point, it has excellent low-temperature fixability and a relatively low temperature. The area fixing process can easily form a smooth image surface. (2) The copolymer constituting the binder resin does not have an ester bond (polar group) in its main chain, and has a long side formed by the alkyl group or alkenyl group represented by R ² in Chemical formula 2 above. Since it has a chain, the hot offset resistance is improved due to the entanglement effect and the reduction of the wettability to the fixing roller. (3) Since the copolymer constituting the binder resin has no ester bond (polar group) in its main chain, it has appropriate chemical affinity and electric adhesion to the surface of the photoconductor, and has good transferability and cleaning property. Are better. Moreover, since the affinity for water is small, the environmental dependence of the charging characteristics is small. (4) Since the copolymer constituting the binder resin has a long side chain having an ester bond, good crush resistance is exhibited and hardness is high. Therefore, crushing due to stress due to agitation in the developing device, burial of external additives, and the like are suppressed, and excellent developability, transferability, and cleanability are stably exhibited for a long period of time.

The present invention will be specifically described below. The binder resin that constitutes the color toner of the present invention is
Monomer represented by (hereinafter also referred to as "specific monomer")
And a at least one monomer selected from the group consisting of styrene-based monomers, acrylate-based monomers, and methacrylic-ester-based monomers. It consists of a copolymer.

<Specific Monomer> By using the specific monomer as an essential component of the polymerizable mixture, good crush resistance and high hardness are imparted to the resulting copolymer.
In Chemical Formula 2 representing this specific monomer, the carbon-carbon double bond portion (vinyl group or isopropenyl group) forms the main chain of the copolymer, and the carboxylic acid ester portion forms the side chain of the copolymer. Since the side chain formed by the copolymerization reaction is a long one having an ester bond, a copolymer having good crush resistance and high hardness can be obtained. Further, in combination with the absence of ester bond in the main chain, the effect of entanglement of side chains and the reduction of wettability with respect to the fixing roller can improve the hot offset resistance. The effect of improving offset resistance is
This is especially exhibited when a silicone rubber roller is used as the fixing roller.

In order to lengthen the side chain portion of the copolymer to some extent, the number of carbon atoms of the alkyl group or alkenyl group represented by R ² in the above chemical formula 2 is set to 8 to 18, preferably 12 to 16. It Specific examples thereof include octyl methacrylate, nonyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, octyl acrylate, nonyl acrylate, dodecyl acrylate, tetradecyl acrylate, hexadecyl acrylate and octadecyl acrylate (meth). Examples thereof include acrylic acid esters, partially halogenated products thereof, and alkenyl (meth) acrylates such as dodecenyl methacrylate and dodecenyl acrylate.

The content of the specific monomer in the polymerizable mixture is 2 to 40 mol%. When the content ratio of the specific monomer is less than 2 mol%, in the obtained copolymer,
Sufficient offset resistance, crush resistance, and high hardness cannot be achieved. On the other hand, when this ratio exceeds 40 mol%, the crystallinity of the side chain becomes too high and a large domain is formed in the toner, and the fixed image formed by such a toner has color turbidity. , The light transmission is lost.

<Styrene-based monomer and (meth) acrylic acid ester-based monomer> The polymerizable mixture for forming the copolymer contains a styrene-based monomer and an acrylic acid ester-based monomer together with the specific monomer. At least 1 selected from the group consisting of monomers and methacrylic acid ester-based monomers
A species of monomer is included.

As the styrene-based monomer, alkyl styrene such as styrene, methyl styrene and diethyl styrene, halogenated styrene such as chlorostyrene and the like can be used. When a styrene-based monomer is used, the proportion of the styrene-based monomer in the polymerizable mixture is preferably 49 mol% or less. If the proportion of the styrene-based monomer is too large, the resulting copolymer tends to be brittle and sufficient crush resistance is difficult to be exhibited.

Acrylic acid, methacrylic acid, α-ethylacrylic acid and the like can be used as the (meth) acrylic acid for obtaining the acrylic ester monomer and the methacrylic ester monomer. ) Alcohols for obtaining acrylic acid ester-based monomers include alkyl alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol, and carbon numbers such as halogenated alkyl alcohols obtained by halogenating a part of these alkyl alcohols. Alcohol having 1 to 4 can be preferably used.

In the polymerizable mixture, the ratio of methacrylate (including both the methacrylic acid ester monomer and the methacrylate as the specific monomer) in the polymerizable mixture is preferably 50 mol% or more, More preferably, it is 80 mol% or more. Since the ratio of methacrylate is 50 mol% or more,
The obtained copolymer has a high cohesive energy density and is further excellent in toughness.

<Ion Crosslinking Structure> In the present invention, the copolymer constituting the binder resin preferably has an ionic crosslinking structure introduced into its molecule. Here, the ionic crosslinked structure refers to a crosslinked structure formed by a coordinate bond (ionic bond) between a carboxyl group present in the copolymer and a metal ion.

In order to introduce an ionic crosslinked structure, a polyvalent metal compound may be reacted with a copolymer obtained from a polymerizable mixture containing a carboxyl group-containing monomer.

Here, as the carboxyl group-containing monomer, acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid, β-methylcrotonic acid and the following chemical formula 3
A half-ester compound represented by
Of these, the half-ester compound is particularly preferable because it can efficiently generate ionic cross-linking with the polyvalent metal compound. Specific examples of the half-ester compound include, for example, succinic acid monomethacryloyloxyethyl ester,
Examples thereof include fumaric acid monomethacryloyloxyethyl ester and the like. In order to introduce a sufficient ionic crosslinked structure, the proportion of the carboxyl group-containing monomer in the polymerizable mixture is preferably in the range of 1 to 10 mol.

[0025]

[Chemical 3] [In Chemical Formula 3, R ³ represents a hydrogen atom or a methyl group, and L represents a carbon atom having an ester bond in the molecular chain of 3
The above divalent linking groups are shown. ]

Examples of suitable polyvalent metal compounds include alkaline earth metals, zinc group metal acetates and oxides.

The copolymer having an ionic crosslinked structure is
The crush resistance is further improved, the hardness is further increased, and the toughness as a binder resin at room temperature is further improved. Further, the introduced ionic cross-linking structure can suppress the decrease in glass transition point due to the long side chain formed by the specific monomer. Moreover, since this ionic crosslinked structure is easily cut during melting,
It does not affect the viscosity of the resin at the melting temperature. A copolymer having a cross-linked structure other than the ionic cross-linked structure, for example, a vinyl-based cross-linked structure, may have an excessively high softening point, which is not preferable.

<Softening Point of Binder Resin> The softening point (Tsp) of the binder resin constituting the color toner of the present invention is 90 ° C. or higher and 115 ° C. or lower. Softening point (Tsp) is 9
When the temperature is lower than 0 ° C., the elasticity at the melting temperature becomes too small, the binder resin easily winds around the heat roller, and does not have offset resistance. on the other hand,
When the softening point (Tsp) exceeds 115 ° C., the viscosity at the fixing temperature becomes excessive, and a sufficiently smooth fixed image surface cannot be formed. It becomes inferior in light transmittance. Here, the softening point of the binder resin is the Koka type flow tester “CFT”.
-500 "(manufactured by Shimadzu Corporation). Specifically, using a sample of 1 cm ³ , a nozzle diameter of 1 mm, a nozzle length of 1 mm, a load of 20 kg / cm ² ,
The relationship between the temperature and the outflow rate was measured under the condition that the temperature rising rate was 6 ° C./min, and the temperature at the time when the outflow rate reached 0.5 cm ³ was defined as the softening point (Tsp).

<Glass Transition Point of Binder Resin> The glass transition point (Tg) of the binder resin constituting the color toner of the present invention is more than 50 ° C. and 65 ° C. or less. When the glass transition point Tg is 50 ° C. or lower, the storage stability as a toner is poor, and the crush resistance and high hardness of toner particles cannot be sufficiently satisfied. On the other hand, when the glass transition point Tg exceeds 65 ° C. and the viscosity in the high temperature region becomes excessive, the viscosity at the fixing temperature becomes excessive, and a sufficiently smooth fixed image surface cannot be formed. Here, the glass transition point of the binder resin is
It is measured by DSC "SSC580DS type" (manufactured by Seiko Denshi Kogyo KK). Specifically, temperature 30
C. to 100.degree. C. and temperature rising rate of 10.degree. C./min. For one sample, measurement was performed in the mode of "first temperature increase, rapid cooling, second temperature increase", and The temperature at the extrapolation start point was defined as the glass transition point (Tg).

<Colorant> The colorant constituting the color toner of the present invention is not particularly limited, and commonly used dyes or pigments can be used. In addition,
In producing the color toner of the present invention, a master batch in which a pigment is dispersed and contained in a high concentration in advance by using a flushing process in a part of the binder resin is prepared, and this master batch is mixed with the rest of the binder resin. It is preferable to manufacture a color toner. The color toner manufactured in this manner has excellent dispersibility of the colorant and wettability with the binder resin, and can improve the color developability and further improve the crush resistance and offset resistance of the toner. it can.

<Various Additives> The color toner of the present invention may contain various internal additives and external additives such as a charge control agent, if necessary. As the charge control agent, conventionally known charge control agents can be used, but since they form a part of the color toner particles, they are preferably colorless or white. Specific examples of preferred charge control agents include zinc salts of salicylic acid or salicylic acid derivatives. External additives include fine particles such as commonly used inorganic fine particles and organic fine particles, fatty acids,
A lubricant or the like composed of a fatty acid metal salt or the like can be used.
In particular, by adding the fatty acid metal salt, the coefficient of friction between the toner particles and other substances is reduced, and as a result, the stress on the toner particles is reduced and the crushing of the toner particles and the burial of external additives are more effective. This is preferable because it can be prevented. Examples of preferable fatty acid metal salt include lithium salt, aluminum salt, zinc salt, and magnesium salt of stearic acid. The amount of external additives added is
From the viewpoint of exhibiting the effect of addition and preventing the environmental dependence of charging, it is preferably 0.01 to 1.0% by weight with respect to the colored particles.

<Production Example / Particle Size Range> The method for producing the color toner of the present invention is not particularly limited and can be produced by a conventionally known method. The particle diameter of the color toner of the present invention is in the range of 1 to 30 μm,
From the viewpoint of improving the resolution and surface smoothness of the formed image, the volume average particle diameter is preferably in the range of 3 to 9 μm.

The color toner of the present invention may be mixed with a carrier and used as a two-component developer, or when the color toner is a magnetic toner, it may be used as a one-component developer consisting of only the color toner. You can also As such a carrier, a conventionally known carrier can be used, but a carrier having low magnetization and small specific gravity is preferable. By using such a carrier having low magnetization and low specific gravity, stress applied to the toner particles during mixing and stirring can be reduced. Specifically, the magnetization is 15 to 40 em
A carrier having u / g and a specific gravity of ³ to 7 g / cm ³ can be preferably used. From the viewpoint of improving the durability of the carrier, it is possible to preferably use a carrier in which a resin coating layer is provided on the surface of magnetic particles, or a carrier in which magnetic powder is dispersed in resin particles.

As described above, when the color toner of the present invention is used as a two-component developer by mixing it with a carrier having low magnetization, in order to prevent the carrier from adhering to the surface of the photoreceptor, an oscillating electric field is applied. It is preferable to use a development step which is performed in a non-contact manner below. Further, in this developing step, a plurality of toner images of different colors can be superposed and developed on the surface of the photoconductor, and the color image forming apparatus having such a developing step can be downsized. Have advantages. In a color image forming method in which a plurality of toner images are superposed on a photoconductor by using a non-contact development process under such an oscillating electric field, the non-contact development is carried out. As described above, it is necessary to allow the developer to exist in a thin layer on the developer carrier, and to collectively transfer a plurality of superimposed toner images onto a transfer material such as paper. The color toner of the present invention exhibits excellent performance even in such a color image forming method.

Further, the color toner of the present invention can be preferably used in a fixing process using a heat roller. Here, the heat roller used in the fixing process has a surface layer that is in contact with the surface of the unfixed image on the transfer material made of an elastic body, and is a soft roller that has good followability to irregularities of color toner on the surface of the unfixed image. It is preferable that it is because the surface smoothness of the fixed image can be further improved. Then, in the fixing process as described above,
Since hot offset is likely to occur due to the high adhesiveness of the molten toner to the surface of the heat roller, a large amount of a release agent such as silicone oil is usually applied, but the color toner of the present invention is used. In that case, the amount of the release agent to be applied can be suppressed to a very small amount, and the stickiness of the fixed image due to the applied release agent,
A final fixed image without unevenness can be obtained.

[0036]

EXAMPLES Examples of the present invention will be described below.
The present invention is not limited to these. In addition,
In the following, "part" means "part by weight".

Example 1 Preparation of Copolymer (Binder Resin) Methyl acrylate, methyl methacrylate, octadecyl methacrylate, dodecyl acrylate,
Methacrylic acid and zinc oxide are 5: 80: 5: 5:
A polymerizable mixture having a composition of 5: 0.5 (molar ratio) was subjected to a copolymerization reaction to prepare a resin (Tsp = 102 ° C., Tg = 57 ° C.) composed of a copolymer having an ionic crosslinked structure. . Preparation of Pigment Masterbatch A copolymer having an ionic cross-linking structure prepared in the same manner as described above, and a magenta pigment "CI Pigment No. 1".
No. 22 "was mixed in a weight ratio of 6: 4 and subjected to a flushing treatment to prepare a pigment masterbatch. Production of Color Toner 100 parts of the above-prepared copolymer, 20 parts of the pigment masterbatch prepared above, and 3 parts of zinc salt of 3,5-ditertiarybutylsalicylic acid were mixed in a Henschel mixer, and then 2 parts were mixed. After melt-kneading with a shaft type extruder, cooling and solidifying, and coarsely crushing, colored particles having a volume average particle diameter of 8.5 μm were obtained using a particle collision type fine pulverizer and an airflow classifier. For 100 parts of the obtained colored particles, 0.4 part of hydrophobic silica "R-972" (manufactured by Nippon Aerosil Co., Ltd.) and 0.6 part of hydrophobic titania "T-805" (manufactured by Nippon Aerosil Co., Ltd.) And 0.2 part of aluminum stearate (lubricant) are added and mixed using a Henschel mixer to obtain the color toner T of the present invention.
1 was produced.

<Examples 2 to 7> The composition (molar ratio) of the polymerizable mixture used to prepare the copolymer having an ionic crosslinked structure and the pigment masterbatch was changed according to the formulation shown in Table 1 below. A binder resin having a softening point (Tsp) and a glass transition point (Tg) shown in Table 2 below was prepared in the same manner as in Example 1 except that the type and amount of the lubricant added to the colored particles were determined by the table. Color toners T2 to T7 of the present invention having the volume average particle diameters shown in Table 2 were produced in the same manner as in Example 1 except that the formulation was changed according to the formulation.

[0039]

[Table 1]

[Note that the abbreviations in Table 1 above represent the following compounds. St: Styrene MA: Methyl acrylate MMA: Methyl methacrylate BA: Butyl acrylate BMA: Butyl methacrylate ODMA: Octadecyl methacrylate (specific monomer) DDA: Dodecyl acrylate (specific monomer) OMA: Octyl methacrylate (specific monomer) DDMA: Dodecyl methacrylate (specific monomer) ) MAAc: Methacrylic acid (carboxyl group-containing monomer) Ac-1: Succinic acid monomethacryloyloxyethyl ester (carboxyl group-containing monomer: half ester compound)]

[0041]

[Table 2]

Comparative Examples 1 to 8 Example 1 except that the composition (molar ratio) of the polymerizable mixture used to prepare the copolymer and the pigment masterbatch was changed according to the formulation shown in Table 3 below. A binder resin having a softening point (Tsp) and a glass transition point (Tg) shown in Table 4 described below was prepared in the same manner as described above, and the kind and amount of the lubricant added to the colored particles were shown in Table 3. Comparative color toners H1 to H8 having the volume average particle diameters shown in Table 4 were manufactured in the same manner as in Example 1 except that the above was changed.

[0043]

[Table 3]

[Note that the abbreviations in Table 3 above represent the following compounds. St: Styrene MMA: Methyl methacrylate ODMA: Octadecyl methacrylate (specific monomer) OMA: Octyl methacrylate (specific monomer) DDMA: Dodecyl methacrylate (specific monomer) BMA: Butyl methacrylate BPA-EO: Ethylene oxide adduct of bisphenol A]

[0045]

[Table 4]

<Preparation of Carrier> Weight average particle diameter is 45 μ
Cu-Fe having m, a specific gravity of 5.0 and a saturation magnetization of 22 emu / g (when an external magnetic field of 1000 oersted is applied).
A resin coating layer made of styrene-methylmethacrylate resin [styrene / methylmethacrylate = 4/6 (molar ratio)] is formed on the surface of the core particles of the system at a ratio of 2.0% by weight based on the core particles. Then, a resin-coated carrier was prepared.

<Preparation of Developer> The color toners (T1 to T7 and H1 to H) obtained in the above Examples and Comparative Examples.
Developers 1-7 and comparative developers 1-8 were prepared by mixing each of 8) and the above resin-coated carrier with a V-type mixer so that the toner concentration was 7% by weight. .

<Evaluation of Developer> An image forming test was conducted using the developers 1 to 7 and the comparative developers 1 to 8 obtained as described above, and the surface smoothness of the fixed image, anti-offset property, and development And the transferability and the cleaning property were evaluated.

Here, as the image forming apparatus, a full-color copying machine "DC9028" modified machine (manufactured by Konica Corporation) equipped with a fixing device having a structure as shown in FIG. It was carried out by forming a fixed image by the contact reversal development method.

(Structure of Fixing Device) As shown in FIG. 1, a heater lamp 1 (halogen lamp, 600 W) is built in the center, and L is formed on the surface of a hollow aluminum roller 2 having a diameter of 60 mm.
A fixing device having a fixing roller having a TV rubber layer 3 formed therein and a pressure roller having a heater aluminum lamp 1 built in the center thereof and having an HTV rubber layer 4 formed on the surface of a hollow aluminum roller 2 having a diameter of 60 mm. In the figure, 5 is a cleaning roller, 6 is an oil applying roller, 7 is an oil supply roller, 8 is a silicon oil storage tank, and 9 is an oil regulating blade. The surface temperatures of the fixing roller and the pressure roller can be adjusted, and the fixing linear velocity was set to 160 mm / sec.

(Development conditions) Surface potential: -800 V to -50 V (non-image area to image area) Development gap: 0.5 mm DC bias voltage: -650 V AC bias voltage: 1.6 kV _PP (5 kHz)

(Evaluation Method) Surface Smoothness of Fixed Image The surface temperatures of the fixing roller and the pressure bonding roller were sequentially increased, and the temperature at the time when the surface roughness Ra of the formed image became 0.3 μm or less was measured. Offset resistance The surface temperatures of the fixing roller and the pressure roller were sequentially increased, and the temperature at which hot offset occurred was measured. Developability A fixed image was formed 30,000 times under low temperature and low humidity (10 ° C, relative humidity 20%) and high temperature and high humidity (33 ° C, relative humidity 80%), and electrostatic images were obtained at the initial stage and at the time of 30,000 cycles. The toner amount (developed amount) per unit area was measured for the color toner developed on the surface of the photoconductor to develop the latent image. Transferability The ratio (transfer rate) of the amount of toner transferred onto the support to the amount of toner developed on the surface of the photoconductor was measured at the initial stage and at the time of 30,000 times. Cleaning Property The number of times of image formation was measured at the time when an image defect due to defective cleaning occurred. The above results are shown in Tables 5 to 7 below.

[0053]

[Table 5]

[0054]

[Table 6]

[0055]

[Table 7]

As can be understood from the above results, the color toners T1 to T of the present invention manufactured according to Examples 1 to 7.
No. 7 is excellent in all of the image surface smoothness, anti-offset property, developing property, transfer property and cleaning property, and can form a stable color-fixed image for a long time.

On the other hand, the color toners H1 and H2 in which the ratio of the specific monomer is too small or too large, and the color toner H in which the softening point (Tsp) of the binder resin is too small or too large.
3 to H4, color toners H5 to H6 in which the glass transition point (Tg) of the binder resin is too small or too large, color toner H7 produced without using a specific monomer, and color toner H using a polyester resin as a binder resin.
No. 8 is not one which can exhibit the above performances in a well-balanced manner.

[0058]

INDUSTRIAL APPLICABILITY The color toner of the present invention can form a color fixed image suitable for full-color copying and having excellent surface smoothness by a fixing process in a relatively low temperature range. Does not cause In addition, since it has excellent strength and high toughness that does not cause crushing due to stress due to stirring in the developing device and high hardness that does not cause burial of external additives, it has excellent developability, transferability and cleaning property. Excellent and less dependent on the environment for charging. Therefore, a stable color fixed image can be formed for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a modified fixing device in a full-color copying machine used for an image forming test.

[Explanation of symbols]

 1 Heater Lamp 2 Hollow Aluminum Roller 3 LTV Rubber Layer 4 HTV Rubber Layer 5 Cleaning Roller 6 Oil Applying Roller 7 Oil Supply Roller 8 Silicon Oil Storage Tank 9 Oil Control Blade

Claims (1)

[Claims] 1. A color toner containing at least a binder resin and a colorant, wherein the binder resin is a monomer represented by the following chemical formula 1.
Obtained by a copolymerization reaction of a polymerizable mixture containing at least one monomer selected from the group consisting of a styrene-based monomer, an acrylic acid ester-based monomer and a methacrylic acid ester-based monomer, The ratio of the monomer represented by the following Chemical Formula 1 in the polymerizable mixture is 2 to 40 mol%, and the softening point (Tsp) and the glass transition point (Tg) of the binder resin are in the range represented by the following formula. A color toner characterized by being present. Formula) 90 ° C. ≦ Tsp ≦ 115 ° C. 50 ° C. <Tg ≦ 65 ° C. [In Chemical Formula 1, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a substituted or unsubstituted alkyl group or alkenyl group having 8 to 18 carbon atoms. ]