JP3878009B2 - Method for producing toner for electrostatic image development - Google Patents

Description

【００８２】
【発明の効果】
以上説明したように、本発明によれば、従来に比べ、帯電量の立ち上がり特性に優れ、かつ、帯電量の粒子間のバラツキの少ない静電像現像用トナーを得ることができ、これを用いてスジやムラ等のない高品位な画像形成が可能となる。また、このため、非磁性一成分トナーに適用した場合に、特定の粒径、帯電量のトナー粒子から消費されていく選択的現像等の現象が発生することがなく、常温常湿環境下はもとより高温高湿環境下でもライフエンドまで安定した品質が保証される。
【図面の簡単な説明】
【図１】本発明に使用される熱処理装置の一例を示す概略構成図。
【図２】図１に示す試料噴射室の水平断面構造を示す概略断面図。
【符号の説明】
１０１……熱風発生装置、１０３……熱風噴射ノズル
１０４……試料噴射室、１０５……トナー母体粒子
１０８……試料噴射ノズル、１１０……冷風導入口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic image developing toner used for developing an electrostatic latent image in an image forming apparatus such as a copying machine, a printer, or a facsimile machine.
[0002]
[Prior art]
In general, an electrostatic image developing toner used in an image forming method such as electrophotography or electrostatic printing is obtained by dispersing a colorant, a charge control agent, etc. in a binder resin and then pulverizing it to a desired particle size. It is manufactured.
[0003]
By the way, it is known that the surface structure of the toner particles affects the fluidity and charging characteristics of the toner and thus greatly affects the image quality of the toner image. For this reason, various attempts have been made to control the surface structure of toner particles.
[0004]
As a well-known one, there is a method in which oxide fine particles such as colloidal silica or resin fine particles are adhered to the surface of toner particles after preparation. In recent years, a method has been proposed in which after the toner particles are prepared, a mechanical impact force or heat is further applied to modify the shape and properties of the particle surface.
[0005]
[Problems to be solved by the invention]
However, none of these conventional methods have been able to sufficiently meet recent demands for higher image quality, although certain effects are recognized in improving image quality.
[0006]
That is, recently, image forming apparatuses have been improved in performance and speed, and accordingly, high-performance and high-quality toners that can achieve higher image quality than ever have been demanded. A toner having characteristics that can meet the demand has not been obtained.
[0007]
The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a method for producing a toner for developing an electrostatic image that can improve the image quality of a toner image more reliably.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, a method for producing a toner for developing an electrostatic image according to the present invention includes a heat treatment space in which toner base particles are heat-treated, a hot air supply port for flowing hot air into the heat treatment space, and toner base particles in the above-described manner. Using a heat treatment apparatus provided with a toner base particle supply port for supplying to the heat treatment space so as to be dispersed in hot air, toner base particles containing a binder resin and a colorant are removed from the glass transition point of the toner base particles. Rapid heat treatment is performed immediately after heat treatment with hot air at a temperature of ~ 350 ° C.A method for producing a toner for developing an electrostatic image, wherein the toner base particles after cooling have an average sphericity. 0.70 ~ 0.92 And the volume average particle size difference from the toner base particles before heat treatment is 0.5 μm or lessIt is characterized by that.Here, the sphericity is a value obtained by dividing the shortest diameter of the toner base particles by the longest diameter.
[0009]
In the method for producing a toner for electrostatic image development having the above-described configuration, the toner base particles are heat-treated with hot air at a temperature 80 to 350 ° C. higher than the glass transition point, and then immediately subjected to a rapid cooling treatment. It is possible to obtain a toner having excellent charge amount rising characteristics and little variation in charge amount particles, and by using this, it is possible to form a high-quality image without streaks or unevenness. In addition, since there is little variation in the charge amount as described above, a phenomenon such as selective development that is consumed from toner particles having a specific particle size and charge amount occurs when applied to non-magnetic one-component toner. The toner can be made free of toner. Furthermore, the use of the toner obtained by the present invention increases the efficiency of developability, transferability, etc., so that it is possible to widen the range of device setting conditions.
[0012]
The sphericity of the toner base particles after cooling is more preferably in the range of 0.70 to 0.92.
[0013]
In the present invention, an external additive containing at least silica fine particles can be externally added to the cooled toner base particles. According to this configuration, a particularly remarkable effect can be obtained in the image quality improvement effect and the like.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
The toner base particles used in the present invention contain at least a binder resin and a colorant.
[0015]
Binder resins include styrene resins, acrylic resins, olefin resins, diene resins, polyester resins, polyamide resins, epoxy resins, silicone resins, phenol resins, petroleum resins, urethane resins, toners, etc. Various thermoplastic synthetic resins and natural resins that have been conventionally used as binder resins for use can be used. These resins may be used alone or in a combination of two or more.
[0016]
In the present invention, the glass transition point (Tg) is 50 to 75 ° C., the softening point is 80 to 160 ° C., the number average molecular weight (Mn) is 1000 to 30000, and the weight average molecular weight (Tw) / number. It is preferable to use a resin having an average molecular weight (Mn) of 2 to 100. In particular, when a full color toner (including black toner) is intended, the glass transition point is 50 to 75 ° C., the softening point is 80 to 120 ° C., the number average molecular weight is 2000 to 30000, and the weight average molecular weight / number It is preferable to use a resin having an average molecular weight of 10 to 40. Here, the number average molecular weight and the weight average molecular weight are values calculated by styrene conversion using a GPC (gel permeation chromatography) method.
[0017]
As the polyester resin, a polyester resin obtained by polycondensation of a polyhydric alcohol component and a polyvalent carboxylic acid component can be used.
[0018]
Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane Bisphenol A alkylene oxide adducts such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexadiol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol Bisphenol A, hydrogenated bisphenol A, and the like.
[0019]
Examples of the trihydric or higher alcohol component include sorbitol, 1,2,3,6-hexanetetol, 1,4-sorbitol, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerose, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Can be mentioned.
[0020]
Among the polyvalent carboxylic acid components, examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, Adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid, isooctyl succinic acid, their anhydrides or And lower alkyl esters.
[0021]
Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2, 4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexane Examples include tricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, embol dimer acid, acid anhydrides or lower alkyl esters thereof.
[0022]
In the present invention, a polyester resin raw material monomer, a vinyl resin raw material monomer, and a monomer that reacts with both resin raw material monomers are used as the polyester resin. A resin obtained by performing a condensation polymerization reaction to obtain and a radical polymerization reaction to obtain a styrene resin in parallel is also suitable. The monomer that reacts with the raw material monomers of both resins is a monomer that can be used in both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxyl group capable of condensation polymerization reaction and a vinyl group capable of radical polymerization reaction, and examples thereof include fumaric acid, maleic acid, acrylic acid, and methacrylic acid.
[0023]
Examples of the colorant include carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, carmine. 6B, CI Pigment Red 48: 1, CI Pigment Red 122, CI Pigment Red 57: 1, CI Pigment Red 184, CI Pigment Yellow 97, CI Pigment Yellow 12, CI Pigment Yellow 17, CI Pigment Yellow 74, CI Solvent Yellow 162 CI Pigment Yellow 180, CI Pigment Yellow 185, CI Pigment Blue 15: 1, CI Pigment Blue 15: 3, and the like. The content of the colorant is usually 1 to 10 parts by weight, preferably 2 to 6 parts by weight with respect to 100 parts by weight of the binder resin.
The toner base particles may contain a charge control agent, a release agent and the like in addition to the above components.
[0024]
Examples of the charge control agent include those that control the toner to be negatively charged, such as monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids, their metal salts, anhydrides, and esters. , Phenol derivatives such as bisphenol, urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers Examples thereof include a polymer, a styrene-acrylic-sulfonic acid copolymer, and a nonmetal corbonic acid compound. Of these, a metal compound of salicylic acid, a boron complex compound, and calixarene are preferable in terms of chargeability and color.
[0025]
Further, as a toner that controls the toner to be positively charged, for example, modification with quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, nigrosine, fatty acid metal salts, etc. Products, guanidine compounds, imidazole compounds, onium salts such as phosphonium salts and their lake pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannins) Acid, lauric acid, gallic acid, ferricyanic compound, ferrocyanic compound, etc.), metal salts of higher fatty acids, diorganotin borates such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, etc. . Of these, nigrosine and quaternary ammonium are preferable.
[0026]
The content of the charge control agent is usually 0.01 to 20 parts by weight, preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the binder resin.
[0027]
Examples of the release agent include polyethylene wax, polypropylene wax, carnauba wax, rice wax, sazol wax, montan ester wax, monta wax, and Fischer-Tropsch wax. In particular, when a polyester resin is used as the binder resin, it is preferable to use an oxidized wax. Examples of the oxidized wax include polyolefin-based oxidized wax, carnauba wax, rice wax, monta wax, and Fischer-Tropsch wax.
[0028]
The content of the release agent is usually 0.5 to 5 parts by weight, preferably 0.7 to 2.5 parts by weight, with respect to 100 parts by weight of the binder resin.
[0029]
Examples of other additives include silicone oil, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil, and petrolactam.
[0030]
To prepare the toner base particles, a kneading-pulverizing method is used. That is, in the present invention, the above-described binder resin, colorant, and other additives such as a charge control agent blended as necessary are mixed by a mixer such as a Henschel mixer or a ball mill, and then the obtained mixture Is melt-kneaded with a kneader such as a heating roll, kneader, extruder, etc., cooled and solidified, then pulverized to a desired particle size, and classified to be used as toner base particles.
[0031]
In the present invention, the toner base particles thus prepared are subjected to instantaneous heat treatment with hot air at a temperature 80 to 350 ° C. higher than the glass transition point of the toner particles. The volume average particle size of the toner base particles before the heat treatment is preferably 4.0 to 10.0 μm, and more preferably 6.0 to 9.0 μm.
[0032]
For this heat treatment, for example, an apparatus as shown in FIG. 1 can be used.
That is, FIG. 1 is a schematic configuration diagram showing an example of a heat treatment apparatus used in the present invention.
As shown in FIG. 1, the hot air generated by the hot air generator 101 is jetted from the hot air jet nozzle 103 through the introduction pipe 102a. A sample injection chamber 104 is provided around the tip of the hot air injection nozzle 103, and the toner base particles 105 are sent from the quantitative supply device 106 to the sample injection chamber 104 through the introduction tube 102b by pressurized air.
[0033]
As shown in FIG. 2, the sample ejection chamber 104 has a hollow donut shape, and a plurality of sample ejection nozzles 108 are arranged at equal intervals on the inner wall. The toner base particles 105 sent into the sample injection chamber 104 are diffused and evenly dispersed in the sample injection chamber 104, and hot air currents from the plurality of sample injection nozzles 108 are continuously supplied with the pressure of the air. It is injected into the inside.
[0034]
The number of sample injection nozzles 108 is preferably 3 or more, more preferably 4 or more, and these are preferably arranged at equal intervals in the circumferential direction. By using a plurality of sample ejection nozzles 108, the toner base particles 105 can be uniformly dispersed in the hot air stream, and the heat treatment of each toner base particle 1051 can be performed reliably. Further, the toner base particles 105 may be ejected from a slit portion provided on the inner wall of the sample ejection chamber 104 over the entire 360 degrees. As a state of being ejected from the sample ejection nozzle 108 or the slit portion, it is desirable that it is diffused widely at the time of ejection and is dispersed throughout the hot air stream without colliding with other toner base particles.
[0035]
The toner base particles 105 ejected in this way are instantaneously brought into contact with high-temperature hot air and are uniformly heat-treated. Here, “instantaneous” means a time during which necessary modification (heat treatment) is achieved and aggregation of the toner base particles does not occur, although it varies depending on the processing temperature and the concentration of the toner base particles 105 in the hot air stream. Usually, it is 2 seconds or less, preferably 1 second or less. This instantaneous time is expressed as the residence time of the toner base particles 105 until the toner base particles 105 are jetted from the sample jet nozzle 108 and introduced into the introduction tube 102c. Ring particles are likely to be generated.
[0036]
The instantaneously heated toner base particles 105 are immediately cooled by the cold air introduced from the cold air introduction port 110 of the cyclone 109, and pass through the introduction tube 102c without adhering to the inner wall of the apparatus or aggregation of the particles. It is collected in 111 and stored in the product tank 112. Although not shown, the cyclone 111 is preferably provided with a cooling jacket through which cooling water flows in order to prevent aggregation of particles.
[0037]
Other important conditions for performing the instantaneous heat treatment are the hot air temperature, the hot air volume, the dispersed air volume, the dispersed temperature, and the cold air temperature in addition to the hot air temperature.
[0038]
The hot air volume is the volume of hot air supplied by the hot air generator 101. Increasing the amount of hot air is preferable in terms of improving the uniformity and processing capability of heat treatment, and is usually 10 to 1500 l / min. Further, the hot air is controlled so that the temperature distribution of the hot air does not occur in the region where the toner base particles 105 are processed so that uniform heat energy is applied to all the particles, and the hot air is controlled in a laminar flow state. It is preferable that
[0039]
The dispersed air volume is an air volume that is sent to the introduction pipe 102b by pressurized air. The amount of dispersed air is usually 0.5 to 100 l / min from the viewpoint of improving and stabilizing the dispersion state of the toner base particles 105.
[0040]
  The dispersion concentration refers to the dispersion concentration of the toner base particles 105 in the heat treatment region, specifically, the discharge region of the sample injection nozzle 108. A suitable dispersion concentration varies depending on the specific gravity of the toner base particles 105, and a value obtained by dividing the dispersion concentration by the specific gravity of each toner base particle 105 is 50 to 300 g / m.^Three, Preferably 50-200g / m ^Three It is preferable to treat with.
[0041]
  The cold air temperature is the temperature of the cold air introduced from the cold air inlet 110. The toner base particles 105 are preferably returned to an atmosphere below the glass transition point with cold air in order to instantaneously cool the toner base particles 105 to a temperature range where no aggregation or coupling between the particles occurs. Therefore, the temperature of the cold air is 25 ° C or less, preferably 15 ° C or less.Under andTo do. However, it should be noted that if the temperature is lowered more than necessary, condensation may occur depending on conditions, and adverse effects may occur. In this instantaneous heat treatment, since the binder resin is in a molten state for a very short time, adhesion of particles to each other and to the wall of the heat treatment apparatus is prevented. As a result, the stability at the time of continuous production is excellent, the frequency of cleaning of the manufacturing apparatus can be extremely reduced, and the yield can be stably controlled at a high level.
[0042]
  In the present invention, by such heat treatment, the toner base particles after cooling are cooled.averageThe sphericity is preferably 0.65 to 0.98, and the volume average particle size difference from the toner base particles before heat treatment is preferably 0.7 μm or less.averageMore preferably, the sphericity is 0.70 to 0.92, and the volume average particle size difference from the toner base particles before heat treatment is 0.5 μm or less. Such processing conditions include, for example, the temperature of hot air, the amount of hot air supplied from the hot air generator 101, the amount of pressurized air sent to the introduction pipe 107 (dispersed air amount), and the heat treatment region in the above-described apparatus. This can be achieved by appropriately controlling the dispersion density of the toner base particles, the temperature of the cold air introduced from the cold air inlet 110, and the like.
[0043]
Here, a method for measuring the volume average particle diameter and sphericity of the toner base particles (or toner particles) in the present invention will be described.
[0044]
The volume average particle diameter is measured as follows by a Coulter counter measurement method.
For example, using Multisizer II manufactured by Coulter Counter, 1% NaCl aqueous solution is prepared using 1st grade sodium chloride as the electrolyte. As the electrolytic solution, ISOTON R-II manufactured by Coulter Scientific Japan can be used. In 100 to 150 ml of this electrolyte solution, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of measurement sample particles are further added to form a suspension. Disperse this suspension with an ultrasonic disperser for about 1 minute, then measure the volume and number of particles of 2.42 μm or larger in a 256 channel mode using a 100 μm aperture with a measuring device. Calculate to find.
[0045]
  Also,averageThe sphericity is determined by measuring the shape of the particles by connecting an image analysis device such as a multi-image analyzer manufactured by Beckman Coulter, Inc. to the measurement device. The multi-image analyzer measures the number of particles and the particle size distribution based on the electric resistance method, and at the same time, takes a particle image by using a signal generated at the moment when the particle passes through the pore as a timing.
[0046]
In the present invention, after the toner base particles are prepared, a treatment by a known surface modification apparatus may be performed prior to the heat treatment. As such a surface modification treatment apparatus, a surface modification apparatus using a high-speed air current impact method such as a hybridization system manufactured by Nara Machinery Co., Ltd., or a wet coating method such as a mechanofusion system manufactured by Hosokawa Micron Corporation is used. Examples of the applied surface reforming apparatus.
[0047]
In the present invention, the toner base particles thus heat-treated may be subjected to an external addition treatment with an external additive by a conventional means. External additives include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide, diamond carbon lactam and other carbides, nitriding Borides, nitrides such as titanium nitride and molybdenum nitride, borides such as zirconium boride, oxides such as titanium oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, aluminum oxide, silica and colloidal silica, calcium titanate , Titanate compounds such as magnesium titanate and strontium titanate, sulfides such as molybdenum disulfide, fluorides such as magnesium fluoride and carbon fluoride, aluminum stearate, calcium stearate, zinc stearate, stearic acid Metal soaps such as magnesium, talc, inorganic fine particles such as bentonite is used. In the present invention, silica fine particles alone or a combination of silica fine particles and other inorganic fine particles is particularly preferable. These inorganic fine particles are preferably treated with a known hydrophobizing agent such as a silane coupling agent or silicone oil.
[0048]
This external additive is usually used in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, based on 100 parts by weight of the toner base particles. If it is less than 0.1 part by weight, sufficient fluidity cannot be imparted to the toner particles, and the image density may be lowered. On the other hand, when the amount exceeds 5 parts by weight, there is a possibility that the image density is lowered due to fusion with the photoconductor or an increase in charge amount under low temperature and low humidity.
[0049]
The toner thus obtained is obtained by superimposing the toner image formed on the image carrier onto the intermediate transfer member for each color and then transferring the toner image transferred onto the intermediate transfer member to the recording member. It is effectively used for an image forming method including press-transfer on the top.
[0050]
In addition, the toner according to the present invention is effectively used in a one-component developing system in which toner is charged by a developing device passing through a pressure contact portion between a toner regulating blade and a developing sleeve. The development method is suitable for both contact development and non-contact development.
[0051]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples.
In the following description, “part” means “part by weight”. In addition, the volume average particle size and the number distribution of particles having a particle size of 5.0 μm or less use Multisizer II manufactured by Coulter Counter, and the sphericity is determined by Multisizer II manufactured by Beckman Coulter. Connected and asked.
[0052]
Example 1
100 parts of polyester resin (Mw 160,000, Mw / Mn 35, Tg 62 ° C.), CI pigment red 122 4.0 parts as pigment, zinc di-t-butylsalicylate 2.0 parts as charge control agent, Fischer-Tropsch wax (DSC) as release agent After melting 1.5 parts with a Henschel mixer, the mixture was melt-kneaded with a twin-screw extrusion kneader after melting at 88.5 ° C., penetration 3 (25 ° C.), viscosity 7 mPa / s (120 ° C.). After quickly cooling the obtained kneaded product, coarsely pulverized with a speed mill, and further pulverized the pulverized product with a jet pulverizer, followed by classification with a rotor type classifier, the volume average particle size is 8.85 μm, In the number distribution, toner base particles having a particle size of 5.0 μm or less with a particle content of 7.0% by number and an average sphericity of 0.62 were prepared.
[0053]
The toner base particles were heat-treated with the heat treatment apparatus shown in FIG. 1 under the following conditions.
[0054]
[Heat treatment conditions] Toner supply unit: table feeder + vibration feeder, 4 sample injection nozzles (disposed at 90 degree intervals in the circumferential direction), injection angle 30 degrees, hot air flow rate 900 l / min, dispersed air flow rate 60 l / min, Dispersion concentration of toner base particles 100g / m^Three, Hot air temperature 250 ° C, residence time 0.5 seconds, cold air temperature 15 ° C
[0055]
The toner base particles after the heat treatment had a volume average particle size of 9.18 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution of 6.5% by number, and an average sphericity of 0.78.
[0056]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0057]
Example 2
Toner base particles were prepared and heat treated in the same manner as in Example 1 except that the hot air temperature in the heat treatment was 200 ° C. The toner base particles after the heat treatment had a volume average particle size of 9.03 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution, 6.9% by number, and an average sphericity of 0.75.
[0058]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0059]
Example 3
Toner base particles were prepared and heat-treated in the same manner as in Example 1 except that the hot air temperature in the heat treatment was changed to 300 ° C. The toner base particles after the heat treatment had a volume average particle size of 9.25 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution was 6.3% by number, and an average sphericity was 0.80.
[0060]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0061]
Example 4
Toner base particles were prepared and heat-treated in the same manner as in Example 1 except that the hot air temperature in heat treatment was 350 ° C. The toner base particles were heat-treated in the same manner as in Example 1 except that the hot air temperature was 350 ° C. The toner base particles after the heat treatment had a volume average particle size of 9.30 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution of 6.0% by number, and an average sphericity of 0.83.
[0062]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0063]
Example 5
The volume average particle size is 8.82 μm, and the particle size is 5.0 μm in the number distribution, except that 3.0 parts of CI Pigment Blue 15: 3 is mixed instead of CI Pigment Red 122 as a pigment. Toner base particles having the following particle content of 7.3% by number and average sphericity of 0.62 were prepared.
[0064]
The toner base particles were heat-treated in the same manner as in Example 1. The toner base particles after the heat treatment had a volume average particle size of 9.11 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution of 7.1% by number, and an average sphericity of 0.79.
[0065]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0066]
Example 6
In the same manner as in Example 1 except that 3.0 parts of CI Pigment Yellow 17 was mixed instead of CI Pigment Red 122 as a pigment, the volume average particle diameter was 8.93 μm, and the particle diameter was 5.0 μm or less in the number distribution. Toner base particles having a particle content of 6.5% by number and an average sphericity of 0.63 were prepared.
[0067]
The toner base particles were heat-treated in the same manner as in Example 1. The toner base particles after the heat treatment had a volume average particle size of 9.20 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution was 6.3% by number, and an average sphericity was 0.80.
[0068]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0069]
Comparative Example 1
A toner was obtained in the same manner as in Example 1 except that no heat treatment was performed.
[0070]
Comparative Example 2
Toner base particles having a volume average particle diameter of 8.82 μm, a particle content of 5.0 μm or less in the number distribution and a particle content of 7.3% by number, and an average sphericity of 0.62 obtained in the same manner as in Example 5 were obtained. Heat treatment was performed in the same manner as in Example 1 except that the temperature was changed to 0 ° C. The toner base particles after the heat treatment had a volume average particle size of 8.87 μm, a particle content of particle size of 5.0 μm or less in the number distribution, 7.3% by number, and an average sphericity of 0.71.
[0071]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0072]
Comparative Example 3
Toner base particles were prepared and heat treated in the same manner as in Example 1 except that the hot air temperature in the heat treatment was 450 ° C. The toner base particles after the heat treatment had a volume average particle size of 9.62 μm, a content of particles having a particle size of 5.0 μm or less in the number distribution of 6.0% by number, and an average sphericity of 0.90.
[0073]
Hydrophobic silica fine particles treated with hexamethyldisilazane (BET specific surface area of 140 m) were added to 100 parts of the heat-treated toner base particles.²/ g) 1.0 part was added, mixed with a Henschel mixer, and then passed through an ultrasonic vibration sieve to obtain a toner.
[0074]
The toner obtained in each of the above Examples and Comparative Examples was coated with a printer (developing roller; phenol resin containing carbon fine particles and conductive graphite) having substantially the same configuration as plain paper facsimile TF6500 manufactured by Toshiba Tec Corporation. Aluminum roller, blade: Metal blade with urethane resin affixed to the contact part with the development roller, separation distance of 200μm between the photosensitive drum and the development roller) to develop a negatively charged electrostatic image on plain paper After fixing, various evaluations shown below were performed. These results are shown in Table 1.
[0075]
The evaluation was performed after the toner was filled and left for 2 days in a normal temperature and normal humidity environment (23 ° C., 60% RH) and a high temperature and high humidity environment (30 ° C., 80% RH). An image was formed with a predetermined print pattern having a W ratio of 5%.
[0076]
[Filming]
Each surface and image of the photoreceptor and the intermediate transfer member are visually observed after printing 10 sheets (initial stage) and 3000 sheets continuously (endurance) in a normal temperature and humidity environment and a high temperature and high humidity environment, The presence or absence of filming was examined. The evaluation criteria are as follows.
○: No filming is observed on each surface of the photoreceptor and the intermediate transfer member.
Δ: Filming is observed on either the photoreceptor or the intermediate transfer member, but not on the image (no problem in practical use)
X: Filming is recognized on at least one of the photosensitive member and the intermediate transfer member, and is also recognized on the image.
[0077]
[Streak, Unevenness]
After printing 10 sheets in a normal temperature and humidity environment (initial stage) and after continuous printing of 3000 sheets (after endurance), the state of the sleeve of the developing machine and the image were visually observed to check for the presence of streaks and unevenness. The evaluation criteria are as follows.
○: No streak or unevenness is observed on the sleeve.
Δ: Some streaks or unevenness is observed on the sleeve but not on the image (no problem in practical use)
×: Many streaks and unevenness are recognized on the sleeve and on the image
[0078]
[Particle size of toner on sleeve]
Particles with a volume average particle size and number distribution of 5.0 μm or less of the toner remaining in the developing machine after printing 10 sheets in the normal temperature and humidity environment (initial) and after 3000 continuous printing (after durability) The content was measured and compared with the toner before printing. The evaluation criteria are as follows.
○: The difference between the volume average particle size and the content of particles having a particle size of 5.0 μm or less in the number distribution is within 10%.
Δ: The difference in the content of particles whose volume average particle size and number distribution is 5.0 μm or less is 10 to 20%
[0079]
[Image density]
The image density of the printed image after printing 10 sheets (initial) and after 3000 continuous printing (after endurance) in a room temperature and humidity environment was measured with a reflectometer (Macbeth).
[0080]
[Toner consumption]
The amount of toner consumed per sheet (average value) when printing 100 sheets under normal temperature and humidity and high temperature and high humidity environment, and the toner per sheet consumed from 2900 to 3000 sheets when printing 3000 sheets continuously The amount (average value) was determined.
[0081]
  These results are shown in Table 1 together with the heat treatment conditions and the like.
[Table 1]

[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain a toner for developing an electrostatic image that has excellent charge amount rising characteristics and less variation in the amount of charge amount particles compared to conventional ones. High-quality image formation without streaking or unevenness is possible. For this reason, when applied to a non-magnetic one-component toner, a phenomenon such as selective development that is consumed from toner particles having a specific particle size and charge amount does not occur, and under normal temperature and humidity conditions, Stable quality is guaranteed at the end of life even in high temperature and high humidity environment.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a heat treatment apparatus used in the present invention.
2 is a schematic cross-sectional view showing a horizontal cross-sectional structure of a sample injection chamber shown in FIG.
[Explanation of symbols]
101 ... Hot air generator, 103 ... Hot air injection nozzle
104 ... Sample injection chamber, 105 ... Toner base particles
108 ... Sample injection nozzle, 110 ... Cold air inlet

Claims (7)

A heat treatment including a heat treatment space in which the toner base particles are heat-treated, a hot air supply port for flowing hot air into the heat treatment space, and a toner base particle supply port for supplying toner base particles to the heat treatment space so as to be dispersed in the hot air. using the apparatus, the toner base particles containing a binder resin and a colorant, the after 80 to 350 was heat treated with hot air at ℃ temperature higher than the glass transition point of the toner base particles, an electrostatic image immediately subjected to rapid cooling process development The toner base particles after cooling have an average sphericity of 0.70 to 0.92 and a volume average particle size difference from the toner base particles before heat treatment of 0.5 μm or less. A method for producing a toner for developing an electrostatic image. The toner base particles after cooling method according to claim 1 Symbol placement of the electrostatic image developing toner, characterized in that the external additive externally added and mixed for at least silica fine particles. The electrostatic image developing toner according to claim 1 or 2 electrostatic image producing method of the developing toner according to, characterized in that for use in an image forming method using an intermediate transfer member. Toner for electrostatic image development, according to claim 1 to 3 any one electrostatic image producing method of the developing toner according to, characterized in that the non-magnetic is used for a one-component developing system. The method for producing toner for electrostatic image development according to any one of claims 1 to 4 , wherein the toner base particle supply port comprises three or more nozzles. In hot air volume 10 to 1500 l / min flow to the heat treatment space, the dispersion air quantity claims 1 to electrostatic image developing toner according to any one of the 5, characterized in that a 0.5 to 100 l / min Production method. Claims 1 to 6 any one electrostatic image producing method of the developing toner according to, wherein the dispersion concentration of the toner base particles in the heat treatment space is 50~300 g / m ^3.

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