JP2010026404A - Method of manufacturing base toner for mixed toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing base toner for mixed toner, which reproduces image hues without readjusting physical properties of surface charges on each base toner for a new combination of the base toner, even when the combination of the base toner to be mixed is changed, and also which constantly maintains the image hues in continuous printing. <P>SOLUTION: The method is provided for manufacturing the base toner for the mixed toner obtained by mixing at least two kinds of toner. The method includes a process for kneading at least polyester and charge controlling agent by a kneading machine with a screw. The storage modulus of the polyester at 100°C is 5.0×10<SP>2</SP>-1.0×10<SP>5</SP>Pa, and the charge controlling agent includes a salicylic acid compound of 2-5 pts.wt. and fourth grade ammonium salt of 0.3-1.0 pt.wt. per the polyester of 100 pts.wt. The kneading is conducted under the conditions that the kneading energy represented by formula (A): kneading energy [(kw×min×hr)/(r×kg)] = äelectric power of kneading machine (kg)} / ä(screw rotation speed of kneading machine [r/min]) × (supply feed amount of kneading machine [kg/hr])} is 1.00×10<SP>-3</SP>-1.50×10<SP>-3</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a base toner for mixed toner used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, etc., and mixing using the base toner obtained by the method The present invention relates to a method for suppressing hue change of an image during continuous printing of toner and mixed toner.

  Various technologies for mixing two or more color toners with different colors have been studied for the purpose of manufacturing custom color toners that can meet various user requirements and two-color printing that can simplify the equipment. . For example, in Patent Document 1, for the purpose of enabling stable printing even when continuous printing is repeated, an attempt is made to homogenize the toner surface by focusing on the toner surface treatment agent.

On the other hand, as means for improving the dispersibility of the additive in the toner, there is a method of adjusting the kneading energy when kneading the toner raw material in addition to studying the kind and amount of the additive (Patent Document 2). 3)
JP-A-2005-316124 JP 4-110861 A JP 2005-24771 A

  However, even if the toner surface is homogenized by the method described in Patent Document 1, a stable image can be obtained with continuous printing, but the developed color changes depending on the color combination of the toner (base toner) to be mixed. There is.

  An object of the present invention is to reproduce the hue of an image without the need for readjustment of physical properties such as surface charge of each base toner with respect to a new combination of base toners, even when the combination of base toners to be mixed is changed. In addition, in continuous printing, a method for producing a base toner for a mixed toner capable of maintaining a constant hue of an image, a mixed toner using the base toner obtained by the method, and a continuous printing of the mixed toner It is an object to provide a method for suppressing hue change of an image. In the present invention, each toner constituting the mixed toner is referred to as a base toner.

The present invention
[1] A method for producing a mixed toner base toner obtained by mixing two or more kinds of toners, the method comprising a step of kneading at least a polyester and a charge control agent with a kneader equipped with a screw. The storage elastic modulus at 100 ° C. is 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa, and the charge control agent comprises 2 to 5 parts by weight of a salicylic acid compound and a quaternary ammonium salt with respect to 100 parts by weight of the polyester. 0.3 to 1.0 part by weight, and the kneading is performed by the formula (A):

A method for producing a base toner for mixed toner, wherein the kneading energy represented by the formula is 1.00 × 10 ^{−3 to} 1.50 × 10 ⁻³
[2] An image at the time of continuous printing of a mixed toner obtained by mixing two or more types of base toners obtained by the method of [1], and [3] a mixed toner obtained by mixing two or more types of base toners A method of suppressing hue change, comprising: a step of kneading at least polyester and a charge control agent as a base toner with a kneader equipped with a screw, and the storage elastic modulus of the polyester at 100 ° C. is 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa, and the charge control agent contains 2 to 5 parts by weight of a salicylic acid compound and 0.3 to 1.0 parts by weight of a quaternary ammonium salt with respect to 100 parts by weight of the polyester, The kneading is performed using the formula (A):

The present invention relates to a method for suppressing a change in hue of an image during continuous printing of a mixed toner, using a toner obtained by a method performed under a condition that the kneading energy represented by 1.00 × 10 ^{−3 to} 1.50 × 10 ⁻³ .

  The mixed toner obtained by using the base toner obtained by the method of the present invention does not require adjustment of physical properties such as the surface charge of the base toner, regardless of the combination of the base toner to be mixed, such as the color of the toner. It is possible to reproduce the hue and to maintain the constant hue of the image in continuous printing. Further, the method of the present invention can suppress a change in hue of an image during continuous printing of mixed toner.

  The method of the present invention is a method for producing a base toner used for a mixed toner in which two or more kinds of toners are mixed, and includes at least a step of kneading a polyester having a specific storage elastic modulus and a specific charge control agent. In the course of manufacturing the base toner, there is a great feature in that the kneading conditions are adjusted. It is presumed that the hue change of the image when continuously printing using the mixed toner is caused by the fact that the developing property is biased between the base toners. Therefore, as a result of studying the dispersibility improvement of the charge control agent having a great influence on the chargeability of the base toner, the present inventors have found that even when a charge control agent having a good dispersibility is used, It has been found that the problem of the present invention may not be achieved depending on the kneading conditions, and that the problem is achieved by adjusting the kneading energy as the kneading conditions. Further, by combining the base toner obtained by the method of the present invention as each base toner of the mixed toner, even when the combination of the base toners constituting the mixed toner is changed, each of the new base toner combinations is changed. Changes in the hue of the image during continuous printing of the mixed toner can be suppressed without the need to readjust physical properties such as the surface charge of the base toner.

  The base toner manufacturing method of the present invention includes a step of kneading at least a polyester having a specific storage elastic modulus and a specific charge control agent for all the base toners constituting the mixed toner as described above.

The storage elastic modulus at 100 ° C. of the polyester used as the binder resin is 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa, preferably 5.0 × 10 ^{2 to} 5.0 × 10 ⁴ from the viewpoint of low-temperature fixability of the toner. Pa, more preferably 5.0 × 10 ^{2 to} 1.0 × 10 ⁴ Pa. The storage elastic modulus of the polyester can be adjusted by the composition of the raw material monomer of the polyester, the reaction conditions during the production of the polyester, and the like. For example, when a trivalent or higher component is used as a raw material monomer and the reaction time is increased, the storage elastic modulus of polyester at 100 ° C. tends to increase.

  The polyester is obtained by polycondensing a known alcohol component and a known carboxylic acid component such as a carboxylic acid, a carboxylic acid anhydride, or a carboxylic acid ester as raw material monomers.

  Examples of the alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, and the like (I ):

(In the formula, R ¹ O and OR ¹ are oxyalkylene groups, R ¹ is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, and each is a positive number; The average value of the sum of y and y is preferably 1 to 16, more preferably 1 to 8, and even more preferably 1.5 to 4)
Bisphenol A alkylene (2 to 3 carbon) oxide (average added mole number 1 to 16) adduct represented by the formula: ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, Or the alkylene (2-4 carbon atoms) oxide (1-16 average addition mole number) adducts etc. are mentioned.

  The carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid and succinic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octenyl succinic acid, or carbon. Trivalent or higher polyvalent carboxylic acids such as succinic acid, trimellitic acid and pyromellitic acid substituted with alkenyl groups having 2 to 20 carbon atoms, anhydrides of these acids and alkyls of these acids (1 to 3 carbon atoms) ) Esters and the like. The acids as described above, and anhydrides and alkyl esters of these acids are collectively referred to herein as carboxylic acid compounds.

  The alcohol component may contain a monovalent alcohol, and the carboxylic acid component may contain a monovalent carboxylic acid compound as appropriate from the viewpoints of molecular weight adjustment and offset resistance improvement.

  The polyester is obtained, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, in the presence of an esterification catalyst.

  From the viewpoint of durability and fixability, the softening point of the polyester is preferably 80 to 165 ° C, the glass transition point is preferably 50 to 85 ° C, and the acid value is preferably 0.5 to 60 mgKOH / g.

  In the present invention, the polyester may be a polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Polyester.

  As the binder resin, a resin other than the polyester having the specific storage elastic modulus may be used. Examples of binder resins other than polyester include vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and hybrid resins having two or more types of resin components. The content of the polyester is preferably 60 to 100% by weight, more preferably 80 to 100% by weight, and still more preferably 100% by weight in the binder resin.

  As the charge control agent, a salicylic acid compound and a quaternary ammonium salt are used. By using a salicylic acid compound, it is easy to obtain a high charge with good charge rise, and by using a quaternary ammonium salt, it plays a role of suppressing toner particles that are generated by a salicylic acid compound that is too high. it is conceivable that.

  As the salicylic acid compound, the formula (II):

(Wherein R ² , R ³ and R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, M is chromium, Zinc, calcium, zirconium or aluminum, m is an integer of 2 or more, and n is an integer of 1 or more)
A metal compound of a salicylic acid compound represented by The metal compound of the salicylic acid compound may be either a metal salt or a metal complex. In the present invention, a chromium complex of the salicylic acid compound, in which M is chromium, is preferable from the viewpoint of the charging start of the toner. Since the metal compound of the salicylic acid compound is colorless, it can be suitably used in color toners.

In formula (II), R ³ is preferably a hydrogen atom, R ² and R ⁴ is preferably a branched alkyl group, tert- butyl group is more preferable.

Commercially available metal compounds of salicylic acid compounds in which R ³ is a hydrogen atom and R ² and R ⁴ are tert-butyl groups include “Bontron E-81” (M: chromium, manufactured by Orient Chemical Industries), “ Bontron E-84 (M: zinc, manufactured by Orient Chemical Co., Ltd.), TN-105 (M: zirconium, manufactured by Hodogaya Chemical Co., Ltd.), Bontron E-88 (M: aluminum, Orient Chemical Industry Co., Ltd.).

  The compounding quantity of a salicylic acid compound is 2-5 weight part with respect to 100 weight part of said polyester, Preferably it is 2.5-4.5 weight part.

  As the quaternary ammonium salt, the formula (III):

(In the formula, R ^{5 to} R ⁸ may be the same or different and may be substituted with a halogen atom, a lower alkyl group having 1 to 8 carbon atoms, an alkyl group or alkenyl group having 8 to 22 carbon atoms, aryl group or an aralkyl group having 7 to 20 carbon atoms of 6 to 20 carbon atoms, X ^- represents a carboxylate ion)
A quaternary ammonium salt of a carboxylic acid represented by

In the present invention, R ^{5 to} R ⁸ are each a lower alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom, carbon number, since the charging characteristics are more stable and the fixability can be improved. 12-18 alkyl groups, phenyl groups and benzyl groups are preferred, and X ⁻ is preferably an aromatic carboxylate ion or an aliphatic carboxylate ion, more preferably an aromatic carboxylate ion. Examples of aromatic carboxylate ions include carboxylic acid ions having a benzoic acid structure, such as benzoic acid and dithiodibenzoic acid.

  Furthermore, as a more preferred quaternary ammonium salt of dithiodibenzoic acid, in the present invention, a compound of formula (IIIa):

The compound represented by these is mentioned.

  As a commercial product containing the compound represented by the formula (IIIa), “COPY CHARGE PSY” (manufactured by Clariant) and the like can be mentioned.

  The compounding quantity of a quaternary ammonium salt is 0.3-1.0 weight part with respect to 100 weight part of said polyester, Preferably it is 0.4-0.9 weight part.

  The weight ratio of the amount of the salicylic acid compound and the quaternary ammonium salt (salicylic acid compound / quaternary ammonium salt) is preferably 2/1 to 10/1, more preferably 4/1 to 8/1.

  A charge control agent other than the salicylic acid compound and the quaternary ammonium salt may be appropriately used as long as the effects of the present invention are not impaired.

  In the present invention, in addition to the binder resin and the charge control agent, a colorant, a release agent, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, a magnetic substance, etc. These additives may be blended as a toner raw material.

  As the colorant, all of dyes and pigments used as toner colorants can be used according to the desired color. For example, for yellow toner, CI Pigment Yellow (PY) 3, 12, 13, 14, 16, 17, 55, 65, 73, 74, 83, 94, 95, 97, 120, 151, 154, 167, 169, 172, 180, 181, 185 and mixed pigments thereof. For magenta toner, CI Pigment Red (PR) 5, 31, 57: 1, 122, 146, 147, 150, 176, 184, 202, 269, CI Pigment Violet (PV) 19 and mixed pigments of these are available. Can be mentioned. Examples of cyan toner include mixed pigments of C.I. Pigment Blue (P.B.) 15: 3, C.I. Pigment Blue 15: 3 and C.I. Pigment Green (P.G.) 7 or C.I. Pigment Green 36. Incidentally, the mixed pigment referred to here may be used in combination with the respective raw materials of the toner, and is used by blending with the other toner raw materials in a state where both are premixed with the same particle size. May be. The content of the colorant is preferably about 1 to 15 parts by weight with respect to 100 parts by weight of the binder resin.

  Mold release agents include polypropylene wax, polyethylene wax, synthetic wax such as Fischer Tropu, coal wax such as montan wax, petroleum wax such as paraffin wax, wax such as alcohol wax, carnauba wax, rice wax, candelilla Natural ester waxes such as wax may be mentioned, and these may be used alone or in admixture of two or more. The content of the release agent is preferably 0.5 to 10 parts by weight and more preferably 1 to 8 parts by weight with respect to 100 parts by weight of the binder resin.

  In the kneading of the binder resin and the charge control agent, it is preferable to uniformly mix the binder resin, the charge control agent, and the toner materials such as the colorant and the release agent, and then use the mixture in a kneader. The mixing of the toner raw materials may be a method in which all the raw materials such as the binder resin are mixed at once, or a method in which the toner raw materials are divided and mixed.

  Examples of the mixer used for mixing the toner raw material include a Henschel mixer and a super mixer. A Henschel mixer is preferable from the viewpoint of dispersibility of an internal additive such as a charge control agent.

  As a kneader equipped with a screw used for kneading the toner raw material, a closed kneader, a uniaxial or biaxial extruder, an open roll type kneader, etc. are used. Among these, from the viewpoint of kneading stability. A twin screw extruder is preferred.

  The kneading is performed by the formula (A):

The kneading energy is represented by the following conditions: 1.00 × 10 ^{−3 to} 1.50 × 10 ⁻³ , preferably 1.20 × 10 ^{−3 to} 1.40 × 10 ⁻³ . Here, the power of the kneading machine is that when a kneading load is applied, and using the current I (A) and voltage V (V) of the kneading machine, the formula (B):
Electric power of kneader = √3 × I × V × cosφ × 0.001 (B)
(Cosφ is a power factor and varies between 0.5 and 1 depending on conditions, but the value is calculated as 0.8)
Calculate from

  When the polyester having the specific storage elastic modulus described above as the binder resin and the above-described two specific charge control agents are used as the toner raw material, kneading within the range of the kneading energy described above can reduce the production lot. Even if it changes, it is effective in that the dispersion state of the toner raw material can be made constant. By kneading within a specific kneading energy range, a dispersion state of an internal additive such as a charge control agent other than the binder resin in the binder resin can be obtained.

  The kneading temperature may be in a range where the toner raw material can be kneaded, but is preferably at least 30 ° C. lower than the softening point of the polyester and below 50 ° C. higher than the softening point of the polyester. More preferably, the temperature is not less than 30 ° C. lower than the softening point of the polyester and not more than 30 ° C. higher than the softening point of the polyester. The kneading temperature is one of the means for changing the kneading energy. Even if the kneading temperature is changed, if the kneading energy is the same, a toner material having a constant dispersion state can be obtained.

  After the kneading step, the obtained kneaded product is cooled to such an extent that it can be pulverized, and then a base toner can be obtained through ordinary methods such as a pulverizing step and a classification step.

  In the pulverization step, it is desirable to pulverize the volume-median particle size to 20 μm or less, more preferably 10 μm or less from the viewpoint of improving durability.

  The pulverization process may be performed in multiple stages. For example, the kneaded material may be coarsely pulverized to about 1 to 5 mm and further finely pulverized. Moreover, in order to improve the productivity at the time of a grinding | pulverization and a classification process, you may grind | pulverize, after mixing a kneaded material with inorganic fine particles, such as hydrophobic silica.

  The pulverizer used in the pulverization step is not particularly limited. For example, examples of the pulverizer suitably used for the coarse pulverization include an atomizer and a rotoplex, but a hammer mill or the like may be used. Further, examples of the pulverizer suitably used for fine pulverization include a jet mill, a collision plate mill, and a rotary mechanical mill.

  Examples of the classifier used in the classification process include an air classifier, an inertia classifier, and a sieve classifier. In the classification step, the pulverized product which has been removed due to insufficient pulverization may be subjected to the pulverization step again, and may be repeated with the pulverization step and the classification step as necessary.

After the kneading step, the toner particles obtained through the pulverization step and the classification step may be used as the base toner as they are, or an external additive may be externally added to the surface of the toner particles and used as the base toner. The volume median particle size (D ₅₀ ) of the toner (particles) is preferably 3 to 12 μm, and more preferably 4 to 10 μm. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide. Among these, silica having a small specific gravity is preferable from the viewpoint of preventing embedding.

As the external additive, silica having a small specific gravity is preferable from the viewpoint of exerting a spacer effect. From the viewpoint of environmental stability, the silica is preferably hydrophobic silica that has been subjected to a hydrophobic treatment. The method for hydrophobizing is not particularly limited, and examples of the hydrophobizing agent include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, methyltriethoxysilane, and the like. The treatment amount of the hydrophobizing agent is preferably 1 to 7 mg / m ² per surface area of the inorganic fine particles.

  The amount of the external additive is preferably 0.01 to 10 parts by weight and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner particles.

  The external addition step is preferably a dry mixing method in which the external additive and toner particles are mixed using a high-speed stirrer such as a Henschel mixer or a super mixer, a V-type blender or the like. The external additives may be mixed in advance and added to a high-speed stirrer or a V-type blender, or may be added separately.

  By mixing two or more types of base toners obtained by the method of the present invention, a mixed toner can be obtained, and even if the mixed toner is subjected to continuous printing, the hue change of the image can be suppressed. The type and mixing ratio of the toner to be mixed are appropriately set according to the target color of the mixed toner. Examples of the mixer used for mixing two or more kinds of base toners include a V-type blender, a tumbler shaker mixer, a nauter mixer, and a Henschel mixer.

  In the mixed toner of the present invention, two or more kinds of base toners are mixed in advance so that an image of a target color can be obtained, and used for developing latent images such as electrophotography, electrostatic recording, and electrostatic printing. The mixed toner of the present invention can be used as a one-component developing toner or as a two-component developer by mixing with a carrier.

  In the present invention, as described above, even when the combination of the base toners constituting the mixed toner is changed by combining the base toner obtained by the method of the present invention as each base toner of the mixed toner, a new base toner is obtained. For this combination, it is not necessary to readjust physical properties such as the surface charge of each base toner, and it is possible to suppress a change in the hue of the image during continuous printing of the mixed toner. Therefore, the present invention further relates to a method for suppressing the hue change of an image during continuous printing of a mixed toner obtained by mixing two or more kinds of base toners, and the toner obtained by the method of the present invention is used as each base toner. The present invention provides a method for suppressing hue change of an image during continuous printing of a mixed toner.

[Storage modulus of resin]
The storage elastic modulus (G ′) before and after heating is measured with a rheometer (ARES, manufactured by TA Instruments) (Strain: 0.05%, frequency: 6.28 rad / sec). The measurement equipment conditions are set as follows.

  Heat / stand the parallel plate at 150 ° C, melt the sample at 150 ° C and place it on the parallel plate so that the gap is 1.5mm to 2.5mm. After cooling, heat up to 180 ° C at 5 ° C / min.

Specifically, the measuring device was set as follows.
Geometry Type = Parallel Plates (ParaPlate)
Diameter = 25.0 [mm]
Gap = 1.5 to 2.5 [mm]
Read Test Fixture Gap = On
Tool Serial Num = 0000
Tool Inertia ......... = 58.0 [g · cm ² ]
Change Gap to Match Tool Thermal Expansion = Off
Tool Thermal Expansion Coefficient = 2.3 [μm / ℃]
Fluid Density ........ = 1.0 [g / cm ³ ]
Fixture Compliance = 0.524 [μrad / g-cm]

Test Type = Dynamic Temperature Ramp (DTempRamp)
Frequency = 6.28 [rad / s]
Initial Temp. = 150.0 [℃]
Final Temp. = 40.0, 150.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 [℃]
Ramp Rate = 20.0, 5.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 [℃ / min.]
Computed Ramp Time = 2:30, 10:00, 0, 0, 0, 0, 0, 0 [h: m: s]
Soak Time After Ramp = 300, 0, 0, 0, 0, 0, 0, 0 [s or h: m: s]
Time Per Measure = 24, 12, 0, 0, 0, 0, 0, 0 [s or h: m: s]
Strain = 0.05, 0.05, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 [%]
Computed Test Duration = 17:30 [h: m: s]
Zone Time = 450, 10:00, 0, 0, 0, 0, 0, 0 [s or h: m: s]
Options = ElectroRheology
Steady PreShear = Off
PreShear Mode = Preshear Off
Delay Before Test = Off
Automatically start test when on Temperature = Off
AutoTension Adjustment = On
Mode = Apply Constant Static Force
AutoTension Direction = Compression
Initial Static Force = 10.0 [g]
AutoTension Sensitivity = 10.0 [g]
When Sample Modulus <= 100.0 [Pa]
AutoTension Limits = Default
Max Autotension Displacement = 3.0 [mm]
Max Autotension Rate = 0.01 [mm / s]
AutoStrain = On
Max Applied Strain = 20.0 [%]
Max Allowed Torque = 300.0 [g-cm]
Min Allowed Torque = 1.0 [g-cm]
Strain Adjustment = 20.0 [% of Current Strain]
Strain Amplitude Control = Default Behavior
Limit Minimum Dynamic Force Used = No
Minimum Applied Dynamic Force = 1.0 [gmf]
Measurement Options = Default Delay Settings
Cycles = 0.5 []
Time = 3 [s or h: m: s]
Correlation: One Cycle Correlate = Off
ElectroRheology Mode = Off
Turn OFF Motor = No
Turn Hold ON = Yes
Turn OFF Temp Controller = No
Set End of Test Temp = Yes
Set End of Test Temp to: = 200.0 [℃]
Oven Air / N2 Switch = Force Air
Dielectric Testing = Off
Steady Stress on Dynamic = 0.0 [Pa]
Analog Data Collection = Off
External Correlation = Off
Measurement Time = 1.0 [s]
Correlation Cycles = 1 []
Enable External Trigger = Off
Delay before initial trigger = 5.0 [s]
Trigger On Time = 2.0 [s]
Trigger Off Time = 2.0 [s]
Number of On / Off Cycles = 1 []

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample is heated at a heating rate of 6 ° C / min. While applying a load of 1.96 MPa with a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . Plot the plunger drop amount of the flow tester against the temperature, and let the softening point be the temperature at which half of the sample flows out.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the sample was heated to 200 ° C at a rate of 10 ° C / min and cooled to 0 ° C at a rate of 10 ° C / min. Start measurement at / min. The glass transition point is defined as the temperature at the intersection of the base line extension below the glass transition point and the tangent that indicates the maximum slope from the peak rising portion to the peak apex.

[Acid value of the resin]
Measured by the method of JIS K0070. However, only the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Volume-median particle size of toner (D ₅₀ )]
In the present specification, the volume-median particle size (D ₅₀ ) of toner particles means the particle size of the toner at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size. .
Measuring instrument: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% by weight Electrolyte dispersion condition: 10 mg of measurement sample was added to 5 mL of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Thereafter, 25 mL of an electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: The dispersion is added to 100 mL of the electrolytic solution so that the particle size of 30,000 toner particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

Example of resin production 1040 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 10 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 199 g of terephthalic acid, and 4 g of dibutyltin oxide (esterification catalyst) was reacted at 230 ° C. under normal pressure for 5 hours under a nitrogen atmosphere, and further reacted for 1 hour under reduced pressure. The temperature was cooled to 210 ° C., 209 g of fumaric acid and 1 g of hydroquinone were added, reacted for 5 hours, and further reacted under reduced pressure to obtain Resin A. Softening point of the resin A is 107.5 ° C., an acid value of 21.3KOHmg / g, a glass transition point of 64.4 ° C., the storage modulus at 100 ° C. was 1.4 × 10 ³ Pa.

Examples A-1 to A-7 and Comparative Examples A-1 to A-7
100 parts by weight of resin A as a binder resin, 4 parts by weight of the colorant shown in Table 1, 1 part by weight of polypropylene wax “High Wax NP-055” (manufactured by Mitsui Chemicals) as a release agent, and a salicylic acid compound as a charge control agent After mixing 3 parts by weight of the chromium complex “Bontron E-81” (Orient Chemical Industries) and 0.5 part by weight of the quaternary ammonium salt “COPY CHARGE PSY” (Clariant) with a Henschel mixer, the twin-screw kneader “PCM- 43 ”(manufactured by Ikegai Co., Ltd.) and kneaded under the conditions shown in Table 1. The obtained kneaded product was cooled with a drum flaker and then roughly pulverized with a cutter mill. Thereafter, the mixture was finely pulverized with a jet mill and classified with an airflow classifier to obtain toner particles having a volume median particle diameter (D ₅₀ ) of 8.5 μm.

  To 100 parts by weight of the obtained toner particles, 0.6 part by weight of hydrophobic silica “R-972” (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS) was added, stirred for 90 seconds, and then with a wire mesh having an opening of 100 μm. The base toner was obtained by sieving.

Examples B-1 to B-11, Comparative Examples B-1 to B-14
1 kg of each of the base toners of Examples or Comparative Examples shown in Table 2 was mixed at a weight ratio of 1: 1 by a 10 L Henschel mixer for 1 minute to obtain a mixed toner.

Test example 1
5kg of ferrite carrier (average particle size: 60μm, saturation magnetization: 68Am ² / kg) is put into the image development device "Vario Stream 9000" (linear speed: 1000mm / sec) manufactured by Osse Printing System. The mixed toner was replenished so that the toner concentration in the developer was 6% by weight, and the mixture was stirred for 10 minutes to prepare a two-component developer, and then 200,000 sheets of images with a printing rate of 0.5% were printed. At that time, the hue of the image printed on the paper was compared with the initial printing (100 sheets), and the change in hue (ΔE) was measured by the following method. The results are shown in Table 2.

[Measurement of ΔE]
The L ^* value, a ^* value, and b ^* value are measured using a color meter “SPM50” (manufactured by Gretag). The color difference (ΔE) is calculated according to the following formula, and the change in hue is evaluated. The results are shown in Table 2. ΔE is preferably 4.0 or less.

(In the formula, L ₁ ^* , a ₁ ^* and b ₁ ^* represent initial values of printing, and L ₂ ^* , a ₂ ^* and b ₂ ^* represent values after printing 200,000 sheets, respectively.)

  From the above results, it can be seen that the use of the mixed toner obtained by combining the base toners of the examples suppresses the hue change of the image in continuous printing even when the base toner color combination is changed.

  The mixed toner using the base toner obtained by the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (5)

A method for producing a base toner for a mixed toner obtained by mixing two or more kinds of toners, comprising a step of kneading at least a polyester and a charge control agent with a kneader equipped with a screw, and the polyester at 100 ° C. a storage elastic modulus ^{5.0 × 10 2 ~1.0 × 10 5} Pa, charge control agent, relative to the polyester to 100 parts by weight, from 2 to 5 parts by weight and the quaternary ammonium salts of the salicylic acid compound 0.3-1.0 Part by weight, and the kneading is represented by the formula (A):

A method for producing a base toner for a mixed toner, which is carried out under the condition that the kneading energy represented by 1.00 × 10 ^{−3 to} 1.50 × 10 ⁻³ .   The method for producing a base toner for mixed toner according to claim 1, wherein the kneader used for kneading is a twin screw extruder. The salicylic acid compound has the formula (II):

(Wherein R ² , R ³ and R ⁴ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, M is chromium, Zinc, calcium, zirconium or aluminum, m is an integer of 2 or more, and n is an integer of 1 or more)
The method for producing a base toner for a mixed toner according to claim 1, wherein in the metal compound of the salicylic acid compound represented by the formula:   A mixed toner obtained by mixing two or more base toners obtained by the method according to claim 1. A method for suppressing hue change of an image during continuous printing of a mixed toner obtained by mixing two or more kinds of base toners, wherein at least polyester and a charge control agent are kneaded as a base toner by a kneader equipped with a screw. The storage elastic modulus of the polyester at 100 ° C. is 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa, and the charge control agent contains 2 to 5 salicylic acid compounds with respect to 100 parts by weight of the polyester. Part by weight and 0.3 to 1.0 part by weight of a quaternary ammonium salt, and the kneading is performed using the formula (A):

A method for suppressing the hue change of an image during continuous printing of a mixed toner, using a toner obtained by a method of kneading energy represented by 1.00 × 10 ^{−3 to} 1.50 × 10 ⁻³ .