JP4773939B2 - toner - Google Patents

Description

  The present invention relates to a toner used in an image forming method using an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

  In electrophotography, a latent image is electrically formed on a photoreceptor by various means, and then the latent image is developed with toner to form a toner image. Thereafter, the toner image is transferred to a transfer material such as paper as necessary, and then the toner image is fixed to the transfer material using a fixing method such as heat and pressure fixing to obtain an image. .

In the heat roller fixing method and the film fixing method, fixing is performed by allowing a toner image on a fixing sheet to pass through a heat roller or a fixing film. In this fixing method, the surface of the heat roller or the fixing film and the toner on the fixing sheet come into contact with each other, so that the thermal efficiency when the toner is fused on the fixing sheet is extremely good, and the fixing can be performed quickly. It is very good as an electrophotographic apparatus. However, in the above fixing method, the surface of the heat roller or the fixing film and the toner come into contact with each other in a molten state, so that a part of the toner adheres to the surface of the heat roller or the fixing film. For this reason, an offset phenomenon occurs in which the toner adhered to the surface of the heat roller or the fixing film is re-transferred to the next fixing sheet, and the fixing sheet may be soiled.
Considering the recent demands for miniaturization, weight reduction, energy saving, and high reliability, it is necessary to further improve the toner performance such as fixing property and offset resistance, and further improvement of the toner is necessary.

In view of this, for the purpose of achieving both toner fixability and charging stability, a toner having a specific value measured by a thermally stimulated current measuring device is disclosed (for example, Patent Documents 1 to 4). However, there is a demand for a toner having further improved low-temperature fixability and glossiness compared to the toner described in the above patent document.
JP-A-8-62885 JP 2004-279434 A JP 2004-301990 A JP 2005-43851 A

  An object of the present invention is to provide a toner that solves the problems in the conventional techniques described above. That is, an object is to provide a toner having good charging stability, low-temperature fixability and glossiness.

As a result of intensive studies, the present inventors have found that a toner that can solve the above problems can be obtained when the current value measured by the thermally stimulated current measuring device of the toner has a peak in a specific temperature range. The invention has been completed.
That is, the present invention relates to a toner having toner particles containing at least a binder resin, a colorant and a wax, and an inorganic fine powder. (1) Measured at the first temperature rise by the thermal stimulation current measuring device for the toner. When the current value of the thermal stimulation current is in the range of 65 to 100 ° C., the main peak (
Has P1), (2) after the measurement, the current value of the thermal stimulation current measured during the second heating, 6
The present invention relates to a toner having at least two peaks (P2, P3) in a range of 5 to 110 ° C., and having a high temperature side peak (P3) at 85 ° C. or higher.

  According to the present invention, a toner having good charging stability and low-temperature fixability can be obtained even during high-speed printing, and a high-quality image with high gloss can be formed.

  The toner of the present invention has a main peak (P1) measured at the first temperature rise with a thermally stimulated current measuring device in the range of at least 65 to 100 ° C., and the current measured at the second temperature rise. The value has at least two peaks (P2, P3) in the range of 65 to 110 ° C, and the high temperature side peak (P3) exists at 85 ° C or higher.

According to the study by the present inventors, P1 is estimated to be due to a charge relaxation phenomenon accompanying melting of the wax component existing in the vicinity of the toner particle surface. When the temperature indicating P1 is lower than 65 ° C., the high temperature offset resistance may be deteriorated, and when it is higher than 100 ° C., the low temperature fixability may be deteriorated. The absolute value of the current indicating P1 is estimated to be proportional to the amount of wax existing in the vicinity of the toner particle surface. The absolute value of the current indicating P1 is preferably 3.0 × 10 ^{−14 to} 90.0 × 10 ⁻¹⁴ A. If it is less than 3.0 × 10 ⁻¹⁴ A, the amount of wax existing in the vicinity of the toner particle surface is too small, and the low-temperature fixability of the toner is lowered. If it exceeds 90.0 × 10 ⁻¹⁴ A, the amount of wax present in the vicinity of the toner particle surface is excessive, and image density lowering due to durability and poor triboelectric charging may occur.

Since the temperature indicating P2 and the temperature indicating P1 are substantially the same, P2 is a charge relaxation phenomenon caused by melting of the wax component released from the toner particles when heated to 100 ° C., and the absolute value of the current indicating P2 The value is estimated to be proportional to the amount of wax contained in the toner. The absolute value of the current indicating P2 is preferably 1.0 × 10 ^{−14 to} 50.0 × 10 ⁻¹⁴ A. If the density is less than 1.0 × 10 ⁻¹⁴ A, the amount of wax present in the toner particles is too small, and the releasability is lowered, so that the paper is wound around the fixing device. Cheap. If it exceeds 50.0 × 10 ⁻¹⁴ A, the abundance of wax present in the toner particles is excessive, and the stability of development streaks and frictional charging is reduced.

P3 is presumed to be due to a charging relaxation phenomenon accompanying softening of the low molecular weight resin component released from the toner particles when heated to 100 ° C. If the temperature indicating P3 is lower than 85 ° C., the high temperature offset resistance may be lowered, and if it is higher than 110 ° C., the gloss may be lowered. In addition, the absolute value of the current indicating P3 is estimated to be proportional to the amount of the low molecular weight component resin contained in the toner particles. The absolute value of the current indicating P3 is preferably 1.0 × 10 ^{−14 to} 50.0 × 10 ⁻¹⁴ A. If it is less than 1.0 × 10 ⁻¹⁴ A, the resin content of the low molecular weight component present in the toner particles is too small, and the glossiness is lowered. When it exceeds 50.0 × 10 ⁻¹⁴ A, the resin existing amount of the low molecular weight component present in the toner particles is excessive, and the stability of development streaks and frictional charging is lowered.

The toner of the present invention preferably has a viscosity at 100 ° C. in a flow tester of 1.00 × 10 ^{4 to} 4.50 × 10 ⁴ Pa · s. When it is less than 1.00 × 10 ⁴ Pa · s, the high-temperature offset resistance may decrease, and when it exceeds 4.50 × 10 ⁴ Pa · s, the low-temperature fixability and glossiness may be reduced. descend. The viscosity of the toner at 100 ° C. is more preferably 2.00 × 10 ^{4 to} 4.20 × 10 ⁴ Pa · s, and 2.50 × 10 ^{4 to} 4.00 × 10 ⁴ Pa · s. Is more preferable.

The toner of the present invention preferably has a weight average particle diameter (D4) of 3.0 to 9.0 μm in order to faithfully develop finer latent image dots in order to improve image quality. It is more preferable that it is 4.0-7.8 micrometers, and it is still more preferable that it is 5.0-6.5 micrometers.

  A specific method for measuring the physical properties of the toner in the present invention will be described below.

<Measurement of thermal stimulation current>
The thermally stimulated current (TSC) in the present invention is measured by a measurement technique that generates polarization and charge traps inside the sample by applying an electric field to the sample, and detects the current that occurs mainly due to a decrease in depolarization during the temperature rising process. The As such an apparatus, an electron trap measuring system (TS-FETT: manufactured by Rigaku Corporation) can be used. This specific measuring method is described in the TS-FETT operation manual (May 2005 edition) issued by Rigaku Corporation. For example, it is as follows.
(1) First Thermal Stimulation Current Measurement Thermal stimulation current (TSC) is measured by a non-contact method (2 mm) using TS-FETT (manufactured by Rigaku Corporation).
The toner sample for measuring the thermally stimulated current is a toner sample prepared by weighing 1 mg of toner in a normal temperature and humidity environment (temperature 23 ° C., humidity 60%) for 48 hours and weighing the toner sample 6 mg. (A diameter of 6 mm and a depth of 0.5 mm) is put, and the sample surface is smoothed with a glass plate so as to be smooth, and is put in a sample holder to be a measurement sample.
The charging device shown in FIG. 1 is used to charge the measurement sample with a grid voltage of 1 KV and a corona voltage of 20 KV for 30 seconds. Negatively charged toner is negatively charged, and positively charged toner is positively charged.
The TSC measuring device has the configuration shown in FIG. 2, and the sample holder is set on the TS-FETT and heated from 25 ° C. to 100 ° C. at a rate of temperature increase of 1.5 ° C./min. To do.
(2) Second thermal stimulation current measurement The toner sample used for the first thermal stimulation current measurement is cooled to 25 ° C. at a cooling rate of 2 ° C./min.
Using the charging device shown in FIG. 1, the measurement sample is charged with a grid voltage of 1 KV and a corona voltage of 20 KV for 30 seconds. And heated to 120 ° C. at a rate of temperature increase from 25 ° C. to 1.5 ° C./min to measure the current.

<Viscosity measurement>
The viscosity of the toner in the present invention is measured by a constant load extrusion type capillary rheometer, and can be measured by the following means. As an apparatus, for example, a flow tester CFT-500D (manufactured by Shimadzu Corporation) is used, and measurement is performed under the following conditions.
Sample: 1.0 g of toner is weighed and molded with a pressure molding machine to obtain a sample. -Die hole diameter: 1.0mm
-Die length: 1.0mm
・ Cylinder pressure: 9.807 × 10 ⁵ (Pa)
Measurement mode: Temperature rising method Temperature rising rate: 4.0 ° C./min
By the above method, the viscosity (Pa · s) of the toner at 50 ° C. to 200 ° C. is measured, and the viscosity (Pa · s) at 100 ° C. is obtained by the following equation.
η ′ = TW ′ / DW ′ = πPR ⁴ / 8LQ (Pa · s)
However,
TW ′ = PR / 2L (N / m ² )
DW ′ = 4Q / πR ³ (sec ⁻¹ )
η ′: Viscosity (Pa · s)
TW ′: Apparent shear stress of the tube wall (N / m ² )
DW ′: Apparent shear rate of the pipe wall (sec ⁻¹ )
Q: Outflow rate (m ³ / sec)
P: Extrusion pressure (N ^{/ m} 2)
R: Nozzle radius (m)
L: Nozzle length (m)

<Particle size distribution measurement>
The average particle size and particle size distribution of the toner are measured using Multisizer II type (manufactured by Beckman Coulter). As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 ml of the electrolytic aqueous solution, and 5 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and the volume and number of toners of 2.00 μm or more are measured by using the 100 μm aperture as the aperture by the measuring device. Distribution was calculated. Then, the weight-based weight average particle diameter (D4) obtained from the volume distribution according to the present invention was obtained.

<Molecular weight distribution measurement>
Put 5 mg of toner or low molecular weight resin (sample) in 20 mL of tetrahydrofuran (THF), shake, and let stand for 12 hours or more. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corporation, Excro Disc 25CR manufactured by Gelman Science Japan Co., Ltd.), gel permeation A THF sample solution of chromatography (GPC) is used.
[GPC measurement equipment]
In the GPC measurement device, the column is stabilized in a heat chamber at 40 ° C., THF is flowed through the column at this temperature as a solvent at a flow rate of 1 ml / min, and about 100 μl of the THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts (retention time). As a standard polystyrene sample for preparing a calibration curve, for example, a product with a molecular weight of about 10 ² to 10 ⁷ manufactured by Tosoh Corporation or Showa Denko KK is used, and at least about 10 standard polystyrene samples are suitably used. An RI (refractive index) detector is used as the detector.
As a column for molecular weight separation of GPC, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 808P manufactured by Showa Denko KK And TSKgel G1000H (Hx1), G2000H (Hx1), G3000H (Hx1), G4000H (Hx1), G5000H (Hx1), G6000H (Hx1), G7000H (Hx1), and TSKguardcolumn manufactured by Tosoh Corporation.

The toner of the present invention will be described more specifically.
The toner obtained by the present invention has toner particles containing at least a binder resin, a colorant, and a wax, and an inorganic fine powder.

  The toner particles can be produced by a pulverization method, but the effects of the present invention can be obtained. However, the toner particles can be produced by a polymerization method such as emulsion polymerization, dispersion polymerization, suspension polymerization, or seed polymerization. It is preferable to. Among these, it is more preferable to produce toner particles by suspension polymerization.

As the binder resin, known binder resins used for toners can be used. Examples of the polymerizable monomer for producing the binder resin include styrene monomers, acrylic esters, and methacrylic esters. These polymerizable monomers can be used alone or in combination. Among the polymerizable monomers described above, it is preferable from the viewpoint of toner development characteristics and durability that the binder resin is formed by using styrene or a styrene derivative alone or in combination with other polymerizable monomers.

  In order for the current value measured by the thermally stimulated current measuring device to show a peak in a specific temperature range, it is preferable that a resin having a low molecular weight component is present in the toner. This can be achieved by controlling the molecular weight of the binder resin by adding a chain transfer agent or a crosslinking agent when toner particles are produced by a polymerization method. It can also be achieved by preparing a low molecular weight resin in advance and adding the low molecular weight resin to the polymerizable monomer composition to form toner particles. When the low molecular weight resin is added, the weight average molecular weight (Mw) of the low molecular weight resin is preferably 2000 to 7000, and the addition amount is 1 to 100 parts by mass of the polymerizable monomer or the binder resin. 50 parts by mass is preferred.

  As the colorant, black pigments, phthalocyanine pigments, monoazo pigments, bisazo pigments, and quinacridone pigments can be used. Specific examples include the following. Carbon Black, Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Permanent Red, Brilliantamine 3B, Brilliantamine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate; Acridine, Xanthene, Azo, Benzoquinone, Azine, anthraquinone, dioxazine, thiazine, azomethine, indico, thioindico Phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazine, thiazole, include such dyes xanthene. These colorants may be used alone or in combination of two or more.

  Examples of the wax that can be used include the following. Petroleum wax such as paraffin wax and petrolactam and derivatives thereof; montan wax and derivatives thereof; hydrocarbon wax and derivatives thereof according to the Fischer-Tropsch method; polyethylene wax, polypropylene wax; natural wax such as carnauba wax and candelilla wax and derivatives thereof Etc. Furthermore, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or compounds thereof, acid amide waxes, ester waxes, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, and animal waxes. The addition amount of the wax is preferably 5 to 30 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin.

In addition, a resin for the purpose of improving the dispersibility and fixing property of the material or the image characteristics may be contained in the polymerizable monomer composition. Examples of the resin used include polymethyl methacrylate, polyethylene, silicone resin, polyester resin, and aliphatic or alicyclic hydrocarbon resin. These can be used alone or in combination. Among these, a polyester resin is preferable as the resin used by adding to the polymerizable monomer composition.
In controlling the physical properties such as charging property, durability, and fixing property of the toner, either one or both of a saturated polyester resin and an unsaturated polyester resin can be appropriately selected and used. The addition amount of the polyester resin is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin.

  In the present invention, a charge control agent may be added to the toner particles for the purpose of controlling the chargeability of the toner. When toner particles are produced by a polymerization method, the charge control agent is preferably one having little polymerization inhibition and aqueous phase migration. Examples of the positive charge control agent include the following. Examples include triphenylmethane dyes, quaternary ammonium salts, guanidine derivatives, imidazole derivatives, amine compounds, and nigrosine dyes. Examples of the negative charge control agent include the following. Examples thereof include metal-containing salicylic acid copolymers, metal-containing monoazo dye compounds, urea derivatives, styrene-acrylic acid copolymers, and styrene-methacrylic acid copolymers. The addition amount of these charge control agents is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin.

  Examples of the polymerization initiator used when the toner particles are produced by a polymerization method include azo compounds such as 2,2′-azobis- (2,4-dimethylvaleronitrile) and 2,2′-azobisisobutyronitrile. Diazo polymerization initiators; peroxide polymerization initiators such as benzoyl peroxide, t-hexyl peroxypivalate, and t-butyl peroxypivalate.

In the present invention, when a polymerization toner is produced, a known surfactant or organic or inorganic dispersant can be used as a dispersion stabilizer. Since inorganic dispersants are generally large in size, dispersion stability can be obtained due to steric hindrance. Therefore, stability is not easily lost even when the reaction temperature is changed, and washing is easy. Therefore, an inorganic dispersant can be used more preferably. Examples of such inorganic dispersants include the following. Polyvalent metal phosphates such as calcium phosphate and magnesium phosphate; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasuccinate and barium sulfate; calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, Examples thereof include inorganic oxides such as alumina.
These inorganic dispersants may be used alone or in combination with a surfactant for the purpose of adjusting the particle size distribution. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium stearate, and potassium stearate.
In the case of using the emulsion polymerization method, an anionic surfactant, a cationic surfactant, a zwitterionic surfactant or a nonionic surfactant is used.

To the toner used in the present invention, an inorganic fine powder is externally added to the toner particles as an external additive for the purpose of improving charging stability, developability, fluidity and durability. Specific examples of the external additive which is the inorganic fine powder include silica fine powder and hydrophobized silica fine powder. Examples of external additives other than inorganic fine powders include various resin particles and fatty acid metal salts. These are preferably used alone or in combination.
The fine powder of the external additive is preferably treated with a surface treatment agent for the purpose of hydrophobization and chargeability control, if necessary. Specific examples of the surface treating agent include silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having a functional group, and other organosilicon compounds. These treatment agents may be used alone or in combination.
The external additive suitably used in the present invention has a specific surface area by nitrogen adsorption measured by the BET method of 20 m ² / g or more (particularly preferably 30 to 400 m ² / g). The amount used is 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of the toner particles.

  Further, a known lubricant powder may be added to the toner. Examples of the lubricant powder include Teflon (registered trademark), a fluorine resin such as polyvinylidene fluoride; a fluorine compound such as carbon fluoride; a fatty acid metal salt such as zinc stearate; a fatty acid derivative such as fatty acid and fatty acid ester; and molybdenum sulfide. .

It is also preferable to add the following inorganic powder. Examples of the inorganic powder include the following. Oxides of metals such as magnesium, zinc, aluminum, cerium, cobalt, iron, zirconium, chromium, manganese, strontium, tin, antimony; complex metal oxides such as calcium titanate, magnesium titanate, strontium titanate; calcium carbonate Metal salts such as magnesium carbonate and aluminum carbonate; clay minerals such as kaolin; phosphate compounds such as apatite; silicon compounds such as silicon carbide and silicon nitride; and carbon powders such as carbon black and graphite.

  The image forming method using the toner of the present invention is not limited as long as it is an electrophotographic image forming apparatus. More preferably, the electrostatic latent image carrier is primarily charged, a latent image is formed by exposure, the formed latent image is developed by a developing unit, and the resulting toner image is transferred onto a transfer material, and is heated and pressurized. The toner is used as an electrophotographic toner for forming a fixed image.

  Further, the toner of the present invention can be used as either a one-component developer or a two-component developer.

  The present invention will be described by way of examples, but the present invention is not limited to these examples. In addition, all the parts in the following mixing | blending are a mass part.

(Preparation of low molecular weight resin 1)
A glass 4-liter four-necked flask equipped with a thermometer, a stirring bar, a condenser and a nitrogen inlet tube was placed in the oil bath. This was filled with the following composition.
・ Xylene 500 parts ・ Styrene 60 parts ・ Butyl acrylate 40 parts ・ 1,1′-azobis (cyclohexane-1-carbonitrile) 10 parts While stirring this flask at 150 rpm with a stirrer, the temperature of the oil bath was 75 ° C. And the polymerization was carried out by reacting for 10 hours.
After the reaction, xylene was removed from the obtained contents by an evaporator, and then the polymer was added to methanol and precipitated in methanol to purify the low molecular weight resin. When the molecular weight of the obtained low molecular weight resin 1 was measured, it was 3100 in terms of weight average molecular weight (Mw).

(Preparation of low molecular weight resin 2)
Low molecular weight resin 2 was obtained in the same manner as in the preparation of low molecular weight resin 1 except that 12 parts of 1,1′-azobis (cyclohexane-1-carbonitrile) and the reaction temperature were 77 ° C. When the molecular weight of the obtained low molecular weight resin 2 was measured, it was 2200 in weight average molecular weight (Mw).

(Preparation of low molecular weight resin 3)
Low molecular weight resin 3 was obtained in the same manner as in the preparation example of low molecular weight resin 1 except that 8 parts of 1,1′-azobis (cyclohexane-1-carbonitrile) and the reaction temperature were changed to 74 ° C. When the molecular weight of the obtained low molecular weight resin 3 was measured, the weight average molecular weight (Mw) was 4000.

(Preparation of low molecular weight resin 4)
Low molecular weight resin 4 was obtained in the same manner as in the preparation of low molecular weight resin 1 except that 6 parts of 1,1′-azobis (cyclohexane-1-carbonitrile) and the reaction temperature were set to 72 ° C. When the molecular weight of the obtained low molecular weight resin 4 was measured, it was 5500 in weight average molecular weight (Mw).

(Preparation of binder resin fine particle dispersion)
-Styrene 80 parts-N-butyl acrylate 20 parts-Dodecyl mercaptan 0.5 parts Mixing and dissolving the above materials, 1.5 parts of a nonionic surfactant (Sanyo Kasei: Nonipol 400) and anionic In a flask, 2.2 parts of a surfactant (Daiichi Kogyo Seiyaku: Neogen SC) dissolved in 120 parts of ion-exchanged water was dispersed and emulsified. And 10 parts of ion-exchange water which melt | dissolved 2 parts of ammonium persulfate was thrown into this, mixing slowly for 10 minutes, and nitrogen substitution was performed. Then, the contents in the flask are heated with an oil bath until the content reaches 70 ° C., and the emulsion polymerization is continued for 4 hours to disperse the fine particles of the binder resin having a number average particle size of 0.31 μm. A dispersion was prepared.

(Preparation of dispersion of fine particles of low molecular weight resin)
・ Low molecular weight resin 1 50 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 6 parts ・ Ion-exchanged water 200 parts The above materials were heated to 95 ° C. and homogenizer (manufactured by IKA: Ultra Turrax) After dispersion using T50), dispersion was performed with a pressure discharge type homogenizer to prepare a dispersion of fine particles of low molecular weight resin in which fine particles of low molecular weight resin having a number average particle size of 0.5 μm were dispersed.

(Preparation of dispersion of colorant fine particles)
Carbon black (Degussa: Nippon 35) 20 parts Anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 2 parts Ion exchange water 78 parts The above materials were mixed and dispersed using a sand grinder mill. . The number average particle size of the fine particles of the colorant contained in the dispersion of fine particles of the colorant was 0.2 μm, and coarse particles exceeding 1 μm were not observed.

(Preparation of fine particle dispersion of release agent (wax))
-Paraffin wax (Nippon Seiki: HNP-9) 50 parts-Anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 6 parts-Ion-exchanged water 200 parts The above materials are heated to 95 ° C and homogenizer (IKA Co., Ltd .: Ultra Turrax T50) is dispersed using a pressure discharge type homogenizer, and release agent fine particles having a number average particle size of 0.5 μm are dispersed. A dispersion was prepared.

(Preparation of dispersion of fine particles of polyester resin)
Polyester resin 50 parts (polycondensation product of propylene oxide modified bisphenol A and isophthalic acid (molar ratio 1: 1), Tg = 65 ° C., Mw = 10000, Mn = 6000)
・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 6 parts ・ Ion-exchanged water 200 parts The above materials were heated to 95 ° C. and dispersed using a homogenizer (IKA: Ultra Turrax T50). Thereafter, dispersion treatment was performed using a pressure discharge type homogenizer to prepare a dispersion of fine particles of a polyester resin obtained by dispersing a polyester resin having a number average particle diameter of 0.5 μm.

(Preparation of fine particle dispersion of charge control agent)
20 parts aluminum compound of 3,5-di-tert-butylsalicylic acid 2 parts anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) 78 parts ion-exchanged water The above materials are mixed, and a sand grinder mill is used. Used to disperse. The number average particle size of the charge control agent fine particles contained in the dispersion liquid of the charge control agent fine particles was 0.22 μm, and no coarse particles exceeding 1 μm were observed.

<Example 1>
3 parts by weight of calcium phosphate was added to 900 g of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare an aqueous medium.
Further, the following materials were put into a TK homomixer, heated to 60 ° C., stirred at 9,000 rpm, dissolved and dispersed.
-Styrene 80 parts-N-butyl acrylate 20 parts-Low molecular weight resin 1 25 parts-Paraffin wax (manufactured by Nippon Seiki: HNP-9) 10 parts-Carbon black (Degussa: Nippon 35) 6 parts-3,5- 1 part of aluminum compound of di-tert-butylsalicylic acid 6 parts of polyester resin (polycondensation product of propylene oxide modified bisphenol A and isophthalic acid (molar ratio 1: 1), Tg = 65 ° C., Mw = 10000, Mn = 6000 )
Furthermore, 7 parts of t-hexyl peroxypivalate (“Perhexyl PV” manufactured by NOF Corporation) was dissolved in the above material as a polymerization initiator to prepare a polymerizable monomer composition.
The polymerizable monomer composition was put into the aqueous medium, and granulated by stirring at 8,000 rpm using a TK homomixer at 60 ° C. in a nitrogen atmosphere.
Then, the temperature was raised to 70 ° C. over 2 hours while stirring by transferring to a propeller type stirring device, and further 4 hours later, the temperature was raised to 80 ° C. at a rate of temperature rise of 40 ° C./Hr and reacted at 80 ° C. for 5 hours. Went. After completion of the polymerization reaction, the slurry containing the particles was cooled, washed with 10 times the amount of water as the slurry, filtered and dried, and then the particle size was adjusted by classification to obtain black toner particles.
A black toner (Bk1) was obtained by mixing 1.5 parts of silica (R972 manufactured by Aerosil Co., Ltd.) with 100 parts of the black toner particles using a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.). Table 1 shows the physical properties of the black toner (Bk1), yellow toner (Y1), magenta toner (M1), cyan toner (C1), and black toner (Bk2-13, comparative Bk1-4) described later.

<Example 2>
C. instead of carbon black I. A yellow toner (Y1) was obtained in the same manner as in Example 1 except that CI Pigment Yellow 17 was used.

<Example 3>
C. instead of carbon black I. A magenta toner (M1) was obtained in the same manner as in Example 1 except that CI Pigment Red 122 was used.

<Example 4>
C. instead of carbon black I. A cyan toner (C1) was obtained in the same manner as in Example 1 except that CI Pigment Blue 15: 3 was used.

<Example 5>
A black toner (Bk2) was obtained in the same manner as in Example 1 except that the low molecular weight resin 3 was used instead of the low molecular weight resin 1.

<Example 6>
A black toner (Bk3) was obtained in the same manner as in Example 1 except that the amount of t-hexylperoxypivalate used was 10 parts.

<Example 7>
A black toner (Bk4) was obtained in the same manner as in Example 1, except that 9 parts of pentaerythritol palmitate (melting point: 69 ° C.) was used instead of paraffin wax.

<Example 8>
A black toner (Bk5) was obtained in the same manner as in Example 6 except that the polymerization temperature was changed from 80 ° C to 85 ° C.

<Example 9>
A black toner (Bk6) was obtained in the same manner as in Example 1 except that the amount of t-hexylperoxypivalate used was 4 parts.

<Example 10>
A black toner (Bk7) was obtained in the same manner as in Example 1 except that the amount of paraffin wax used was 8 parts and the amount of polyester resin used was 12 parts.

<Example 11>
A black toner (Bk8) was obtained in the same manner as in Example 7 except that the amount of pentaerythritol palmitate was 12 parts and the amount of the polyester resin was 3 parts.

<Example 12>
A black toner (Bk9) was obtained in the same manner as in Example 1 except that the amount of paraffin wax used was 5 parts.

<Example 13>
A black toner (Bk10) was obtained in the same manner as in Example 1 except that the amount of paraffin wax used was 16 parts.

<Example 14>
A black toner (Bk11) was obtained in the same manner as in Example 1 except that the amount of the low molecular weight resin 1 used was 10 parts.

<Example 15>
A black toner (Bk12) was obtained in the same manner as in Example 1 except that the amount of the low molecular weight resin 1 used was 40 parts.

<Example 16>
・ Binder resin fine particle dispersion 90 parts (solid content)
・ 25 parts of low molecular weight resin fine particle dispersion (solid content)
・ Particulate dispersion of mold release agent 10 parts (solid content)
・ Colorant fine particle dispersion 6 parts (solid content)
The above materials were put into a 2 liter separable flask equipped with a stirrer, a condenser, and a thermometer and stirred. This mixed solution was adjusted to pH = 5.2 with 1N aqueous potassium hydroxide solution.
As a flocculant, 50 parts of a 20% aqueous sodium chloride solution is added dropwise to the above mixture, and the flask is heated to 50 ° C. while stirring in a heating oil bath and held at 50 ° C. for 1 hour to produce core agglomerated particles. did.
Further, 10 parts (solid content) of the fine particle dispersion of the binder resin, 6 parts (solid content) of the fine particle dispersion of the polyester resin, and 1 part (solid content) of the fine particle dispersion of the charge control agent The mixture was further maintained at 50 ° C. for 30 minutes to prepare a core / shell aggregated particle dispersion.
After adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku: Neogen SC) to the core / shell aggregated particle dispersion, the flask was sealed, heated to 95 ° C. and held for 4 hours. After cooling, the product was filtered, washed thoroughly with ion-exchanged water, dried, and then the particle size distribution was adjusted by classification to obtain black toner particles 10.
To 100 parts of the black toner particles, 1.5 parts of silica (R972 manufactured by Aerosil Co., Ltd.) was mixed with a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.) to obtain a black toner (Bk13).

<Comparative Example 1>
A black toner (Comparative Bk1) was obtained in the same manner as in Example 7 except that the low molecular weight resin 2 was used instead of the low molecular weight resin 1.

<Comparative example 2>
A black toner (Comparative Bk2) was obtained in the same manner as in Example 1 except that the low molecular weight resin 4 was used instead of the low molecular weight resin 1.

<Comparative Example 3>
A black toner (Comparative Bk3) was obtained in the same manner as in Example 7 except that the low molecular weight resin 1 was not used.

<Comparative example 4>
A black toner (Comparative Bk4) was obtained in the same manner as in Example 1 except that stearyl stearate (melting point: 61 ° C.) was used instead of paraffin wax.

[Experimental Examples 1-13, Comparative Experimental Examples 1-4]
Color laser beam printer LBP5500 (manufactured by Canon Inc.) is modified to use a black developer Bk1-13 or comparison Bk1-4 as a black developer in each experimental example and comparative experimental example as shown in Table 2. Y1, M1 as a magenta developer, and C1 as a cyan developer were used. Then, under a high temperature and high humidity environment (30 ° C., 80% RH), an image having a printing ratio of 5% in area ratio was printed out in a continuous mode up to 8000 sheets. A4 size CLC color copy paper (manufactured by Canon Inc., weighing 80 g / m ² ) was used as the recording material. Thereafter, the following items were evaluated. The evaluation results are shown in Table 2.

(1) High-temperature offset property A solid image of 5 cm × 5 cm area is formed at an amount of 0.60 mg / cm ² with black toner applied at the center of the front end of the recording material, and the fixing speed is 150 mm / sec. Fixing heating when a hot offset phenomenon (a phenomenon in which a part of the fixed image adheres to the surface of the fixing device and then fixes on the recording material in the next round) occurs at the rear end of the recording material in the paper passing direction. The temperature of the surface of the part was measured to determine the temperature at which the hot offset phenomenon occurred and was evaluated based on the following evaluation criteria.
A: 190 ° C or higher (good)
B: 185 ° C or higher and lower than 190 ° C (no problem in practical use)
C: 180 ° C or higher and lower than 185 ° C (practical limit)
D: Less than 180 ° C. (problematic problems)

(2) Low temperature fixability A solid image with a black toner loading of 0.60 mg / cm ² is formed, the fixing speed is 180 mm / sec, and the fixing temperature is modulated every 120 ° C. to 5 ° C. for fixing. The fixed image thus obtained was observed with a symbol paper at 5 reciprocations at a load of about 100 g, and the temperature at which the image peeling was arithmetically averaged at a reflection density reduction rate (%) was 10% or less was determined as the fixing start temperature. It was.
A: Less than 140 ° C. (good)
B: 140 ° C. or higher and lower than 145 ° C. (no problem in practical use)
C: 145 ° C or higher and lower than 150 ° C (practical limit)
D: 150 ° C. or higher (problematic problems)

(3) Development streak A halftone image with a black toner loading of 0.30 mg / cm ² was output, and the image and the developing roller were visually observed and evaluated.
A: Vertical stripes that appear to be development stripes are not seen on the developing roller or the halftone image. There is no practical problem at all.
B: Although there are 1 to 3 fine streaks in the circumferential direction on the developing roller, no vertical streaks are seen on the halftone image. There is no problem in practical use.
C: There are several fine streaks in the circumferential direction on the developing roller, and several fine streaks can be seen on the halftone image. However, it is a level that can be erased by image processing, and there is almost no problem in practical use.
D: Many streaks are seen on the developing roller and the halftone image, and cannot be erased even by image processing. A practically problematic level.

(4) fog The fog density (%) is calculated from the difference between the whiteness of the white portion of the printout image and the whiteness of the transfer paper measured by “REFLECTMETER MODEL TC-6DS” (manufactured by Tokyo Denshoku Co., Ltd.). The fog was evaluated. The filter used was a green filter.
A: Less than 1.0% (good)
B: 1.0% or more and less than 2.0% (no problem in practical use)
C: 2.0% or more and less than 3.0% (practical limit)
D: 3.0% or more (practical problem)

(5) Wrapping A solid image with a black toner loading amount of 0.60 mg / cm ² is formed, and the fixing speed is 150 mm / sec, the fixing temperature is 200 ° C., and the fixing roller is passed through the fixing device. The degree of paper wrapping was visually observed and evaluated.
A: No winding around the fixing roller. (Good)
B: Although it is slightly wound, normal paper discharge is possible. (No problem in practical use)
C: Although it seems to be wound, it can be separated by a separation claw. (Practical limit)
D: The paper is wound around the fixing roller and cannot be discharged. (There are practical problems)

(6) Glossiness A solid image with an applied amount of black toner of 0.60 mg / cm ² is formed, fixing is performed at a fixing speed of 46 mm / sec and a fixing temperature of 180 ° C. ) Using a handy gloss meter gloss meter PG-3D (manufactured by Nippon Denshoku Industries Co., Ltd.), measurement was performed under the condition of a light incident angle of 75 °, and the gloss level of the toner was determined according to the following criteria.
A: 80 or more (good)
B: 60 or more and less than 80 (no problem in practical use)
C: 40 to less than 60 (practical limit)
D: Less than 40 (insufficient for glossy images)

It is the schematic of the charging device used by this invention. It is the schematic of the thermally stimulated current (TSC) measuring apparatus used by this invention. 3 is a diagram illustrating a current measured at the first temperature rise by the thermally stimulated current measuring device for black toner (Bk1) of the present invention. 4 is a diagram illustrating a current measured at the second temperature rise by the thermally stimulated current measuring device for black toner (Bk1) of the present invention. 6 is a diagram showing a current measured at the first temperature rise by a thermally stimulated current measuring device for black toner (Comparative Bk3). It is drawing which shows the electric current measured at the time of the 2nd temperature rise by the thermally stimulated current measuring apparatus of black toner (comparative Bk3).

Claims (6)

In a toner having toner particles containing at least a binder resin, a colorant and a wax, and an inorganic fine powder,
(1) the current value of the thermally stimulated current is measured during the first heating at a thermally stimulated current measuring device of the toner is in the range of 6 5 to 100 ° C., has a main peak (P1),
(2) After the measurement, the current value of the thermally stimulated current is measured during the second Atsushi Nobori, 6 in the range of 5 to 110 ° C., has two peaks (P2, P3) at least, the high-temperature side of the peak ( A toner wherein P3) is present at 85 ° C. or higher. The toner according to claim 1, wherein the absolute value of the current value indicating P3 is 1.0 × 10 ^{−14 to} 50.0 × 10 ⁻¹⁴ A. The toner according to claim 1, wherein the absolute value of the current value indicating P2 is 1.0 × 10 ^{−14 to} 50.0 × 10 ⁻¹⁴ A. The toner according to claim 1, wherein the absolute value of the current value indicating P <b> 1 is 3.0 × 10 ^{−14 to} 90.0 × 10 ⁻¹⁴ A. The toner according to claim 1, wherein the toner has a viscosity at 100 ° C. of 1.00 × 10 ^{4 to} 4.50 × 10 ⁴ Pa · s in a flow tester.   The toner according to claim 1, wherein the toner particles are produced by a suspension polymerization method.

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