JP2010169771A - Method of manufacturing toner, toner, developer, developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a method of manufacturing toner, making uniform the layer thickness of a coating layer, achieving favorable exudation of a release agent in fixing although the coating layer is formed on the surface, and having favorable fixability; the toner manufactured by the manufacturing method; a developer including the toner; and a developing device and an image forming apparatus, which use the developer. <P>SOLUTION: In the method of manufacturing toner, at least a resin fine particle adhesion step, a spraying step and a filming step are performed using a rotary agitating device. Before the resin fine particle adhesion step, pre-treatment base resin particles are made spherical using a hot air type spheronization device, thereby performing a pre-treatment base resin particles surface treatment step of obtaining toner base resin particles, the shape coefficient SF2 of which ranges from 110-135, and the release agent exposure quantity of which on the surface is 2.3 wt.% or more based on the total quantity of the toner base resin particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a toner manufacturing method, a toner manufactured by the manufacturing method, a developer containing the toner, a developing device using the developer, and an image forming apparatus.

  Conventionally, for the purpose of improving the characteristics of powder particles such as toner particles, a surface modification treatment for coating the surface of the powder particles with a coating material has been performed.

  As a method for the surface modification treatment of the powder particles, for example, the powder particles are flowed in the powder flow path by applying a mechanical stirring force to the powder particles by a rotary stirring means such as a screw, blade, or rotor. There is a method of spraying a coating material from a spray nozzle onto powder particles in a fluid state.

  As such a surface modification treatment method, Patent Document 1 discloses that powder particles are caused to flow by rotating a rotary stirring means at a peripheral speed of 5 to 160 m / sec. Disclosed is a method for surface modification of solid particles in which fine solid particles contained in a liquid are fixed to the surface of the powder particles by spraying the liquid, or a film of a coating material contained in the liquid is formed on the surface of the powder particles. ing. According to the surface modification method disclosed in Patent Document 1, the adhesion between the coating material and the powder particles can be improved, and the time required for the surface modification treatment can be shortened.

  Patent Document 2 discloses a method for producing a microcapsule in which a resin layer is attached to the surface of the inner core particle, and a coating layer is formed on the surface of the inner core particle by treating with a solvent that dissolves the resin particle. This production method comprises at least a step of attaching resin particles to the surface of the inner core particles, a step of treating the resin particles with a solvent in which the resin particles dissolve, and a step of drying and collecting the treated particles. According to the manufacturing method disclosed in Patent Document 2, various coating layers can be uniformly controlled with any film thickness.

Japanese Patent Publication No. 5-10971 JP-A-4-21269

  However, since the method disclosed in Patent Document 1 does not consider the irregularities on the surface of the powder particles, if there are many irregularities on the surface of the powder particles, the fine solid particles accumulate in the depressions, so It is difficult to uniformly deposit fine solid particles, and there is a problem that the thickness of the film varies even if a liquid is sprayed to form a film.

  Also, if the powder particle surface is coated with resin fine particles, it will be difficult for the wax to ooze out during fixing, resulting in poor fixability between the toner and the fixing roller, and problems with fixing properties such as high temperature offset. There is a case. These problems cannot be solved even by the method disclosed in Patent Document 2.

  An object of the present invention is a method for producing a toner having a uniform coating layer thickness, good exudation of a release agent during fixing even though the coating layer is formed on the surface, and good fixability, To provide a toner manufactured by the manufacturing method, a developer containing the toner, and a developing device and an image forming apparatus using the developer.

The present invention uses a hot-air spheronizing device to spheroidize pre-treatment mother particles containing a binder resin and a colorant, the shape factor SF2 is 110 or more and 135 or less, and the exposure amount of the surface release agent Performing a pre-treatment mother particle surface treatment step to obtain toner mother particles having a weight percentage of 2.3% by weight or more of the total amount of toner mother particles,
Circulating means for recirculating toner mother particles and resin fine particles in a powder flow path including a rotating stirring chamber and a circulation pipe and returning them to the rotating stirring chamber by a rotating stirring means comprising a rotating disk having a rotating blade and a rotating shaft. And a rotary stirring device comprising a spraying means for spraying a plasticizing liquid capable of plasticizing the toner base particles and the resin fine particles with a carrier gas,
A resin fine particle attaching step for introducing toner fine particles and resin fine particles into the powder flow path in which the rotating stirring means is rotating, and attaching the resin fine particles to the toner mother particle surface;
A spraying step of spraying the plasticizing liquid from the spraying means onto the toner base particles and the resin fine particles in a fluid state;
And a film forming step in which the rotation of the rotary stirring means is continued until the resin fine particles adhering to the toner base particles are softened to form a film, and the toner base particles and the resin fine particles are fluidized. .

  According to the present invention, the toner base particles used in the resin fine particle adhesion step have a surface release agent dispersion diameter of 300 nm or more.

  The present invention also provides a toner manufactured by the toner manufacturing method.

The present invention also provides a developer comprising the toner.
Further, the present invention is a two-component developer comprising the toner and a carrier.

  According to another aspect of the present invention, there is provided a developing device that develops a latent image formed on an image carrier using the developer to form a toner image.

The present invention also provides an image carrier on which a latent image is formed,
A latent image forming means for forming a latent image on the surface of the image carrier;
An image forming apparatus comprising the developing device.

  According to the present invention, the toner manufacturing method performs the pre-treatment mother particle surface treatment step of spheroidizing the pre-treatment mother particles using a hot-air spheronization apparatus. In the pre-treatment mother particle surface treatment step, toner mother particles having a shape factor SF2 of 110 or more and 135 or less and a surface release agent exposure amount of 2.3% by weight or more of the total amount of toner mother particles are obtained. Next, there is provided a rotary stirring device comprising circulating means for repeatedly circulating toner mother particles and resin fine particles in the powder flow path by the rotary stirring means and returning them to the rotary stirring chamber, and spraying means for spraying the plasticizing liquid with the carrier gas. The resin fine particle adhering step, the spraying step, and the film forming step are used.

  By using toner mother particles whose surface is smoothed with a shape factor SF2 of 110 or more and 135 or less in the resin fine particle adhesion process, it becomes possible to uniformly adhere the resin fine particles to the surface of the toner mother particles. Through the steps, a coating layer having a uniform film thickness can be formed on the surface of the toner base particles. As described above, the toner has a coating layer formed on the surface of the toner base particles, and the toner is exposed at the time of fixing by adjusting the exposure amount of the release agent on the surface of the toner base particles to 2.3% by weight or more of the total amount of the toner base particles. Since the release agent exudes promptly, a toner having a wide fixing non-offset region can be obtained. In addition, when a hot air spheronizing device is used to produce toner mother particles having such a structure, the release agent oozes out to the surface simultaneously with the spheroidizing treatment of the mother particles before treatment, so that the surface release The amount of agent exposure can be increased.

  According to the invention, the dispersion diameter of the release agent on the surface of the toner base particles is 300 nm or more. As a result, the release agent exudes more quickly at the time of fixing, so that the fixing non-offset region can be made wider.

  According to the invention, the toner is produced by the production method of the invention. For this reason, the toner has a coating layer having a uniform film thickness. Further, since the release agent exudes quickly during fixing, it has a wide fixing non-offset region.

  According to the invention, the developer contains the toner of the invention. By including the toner of the present invention, the developer has good fluidity and sufficient developability. Also, fixing failure is unlikely to occur. When such a developer is used, a high-quality image can be stably formed.

  According to the invention, the developer is a two-component developer comprising the toner of the invention and a carrier. By including the toner of the present invention, it becomes difficult for the toner component to adhere to the carrier, so that the flowability of the developer is kept good and sufficient developability can be obtained. Also, fixing failure is unlikely to occur. When such a two-component developer is used, a high-quality image can be stably formed.

  Further, according to the present invention, by developing using the developer of the present invention, a high-quality toner image can be stably formed on the surface of the image carrier.

  Further, according to the present invention, a high-quality image can be stably formed by using an image forming apparatus including an image carrier, a latent image forming unit, and the developing device of the present invention.

6 is a flowchart illustrating an example of a procedure of a toner manufacturing method according to the exemplary embodiment. 1 is a front view illustrating a configuration of a toner manufacturing apparatus 201 used in a toner manufacturing method according to a first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 as viewed from a cutting plane line A200-A200. FIG. 3 is a front view showing a configuration around a powder charging unit 206 and a powder recovery unit 207. It is sectional drawing which shows typically the structure of the image forming apparatus 100 which is the 4th Embodiment of this invention. FIG. 6 is a schematic view schematically showing a developing device 14 provided in the image forming apparatus 100 shown in FIG. 5.

1. Toner Production Method The toner production method according to the first embodiment of the present invention includes a pre-treatment mother particle surface treatment step, a resin fine particle adhesion step, a spraying step, and a film forming step.

  FIG. 1 is a flowchart illustrating an example of a procedure of a toner manufacturing method according to the present exemplary embodiment. As shown in FIG. 1, the toner manufacturing method of the present embodiment includes a toner base particle preparation step S1 for preparing toner base particles, a resin fine particle preparation step S2 for preparing resin fine particles, and resin fine particles in toner base particles. Coating step S3 for coating.

(1) Toner mother particle production step S1
In the toner base particle preparation step of Step S1, toner base particles to be covered with the coating layer are prepared. The toner mother particle preparation step S1 includes a pretreatment mother particle preparation step S1a and a pretreatment mother particle surface treatment step S1b. The pre-treatment mother particle surface treatment step S1b is a step of spheroidizing the pre-treatment mother particle preparation step S1a, and the toner mother particles are passed through the pre-treatment mother particle surface treatment step S1b. can get. Pre-treatment mother particles are particles containing a binder resin and a colorant, and are produced by a pulverization method. Hereinafter, a method for producing pre-treatment mother particles by a pulverization method, that is, a pre-treatment mother particle production step S1a by a pulverization method will be described.

(Pre-treatment mother particle production step S1a)
In this step, the pre-treatment mother particle composition containing a binder resin, a colorant and other additives is dry-mixed with a mixer and then melt-kneaded with a kneader. The kneaded material obtained by melt kneading is cooled and solidified, and the solidified material is pulverized by a pulverizer. Thereafter, particle size adjustment such as classification is performed as necessary to obtain mother particles before treatment.

  Known mixers can be used, such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), super mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. Henschel type mixing device, ong mill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like.

  A well-known thing can be used also as a kneading machine, for example, common kneading machines, such as a twin-screw extruder, a 3 roll, a laboratory blast mill, can be used. More specifically, for example, TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (all of which are trade names, manufactured by Ikegai Co., Ltd.), etc. Extruder, Needex (trade name, manufactured by Mitsui Mining Co., Ltd.) and other open roll type kneaders. Among these, an open roll type kneader is preferable.

  As the pulverizer, for example, a jet type pulverizer that pulverizes using a supersonic jet stream, and a solidified material in a space formed between a rotor (rotor) and a stator (liner) that rotate at high speed. An impact pulverizer that introduces and pulverizes can be used.

  For the classification, a known classifier capable of removing the excessively pulverized toner base particles by classification by centrifugal force and classification by wind force can be used. For example, a swirl wind classifier (rotary wind classifier) or the like is used. be able to.

(Base particle raw material before treatment)
As described above, the pre-treatment mother particles include a binder resin and a colorant. The binder resin is not particularly limited, and a known binder resin for black toner or color toner can be used. For example, styrene resins such as polystyrene and styrene-acrylic acid ester copolymer resin can be used. And acrylic resins such as polymethyl methacrylate, polyolefin resins such as polyethylene, polyesters, polyurethanes, and epoxy resins. Moreover, you may use resin obtained by mixing a raw material monomer mixture with a mold release agent and performing a polymerization reaction. Binder resin can be used individually by 1 type, or can use 2 or more types together.

  Among the above-mentioned binder resins, polyester is excellent in transparency and can give toner particles good powder fluidity, low-temperature fixability, secondary color reproducibility, etc., and is therefore suitable as a binder resin for color toners. It is. Known polyesters can be used, and examples thereof include polycondensates of polybasic acids and polyhydric alcohols.

  As the polybasic acid, those known as polyester monomers can be used, for example, terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid and other aromatic carboxylic acids, maleic anhydride, Examples thereof include aliphatic carboxylic acids such as fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid, and methyl esterified products of these polybasic acids. A polybasic acid can be used individually by 1 type, or can use 2 or more types together.

  As the polyhydric alcohol, those known as monomers for polyesters can be used. For example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, cyclohexanediol, cyclohexanediene, etc. Examples thereof include aromatic diols such as alicyclic polyhydric alcohols such as methanol and hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, and propylene oxide adducts of bisphenol A. A polyhydric alcohol can be used individually by 1 type, or can use 2 or more types together.

  The polycondensation reaction between the polybasic acid and the polyhydric alcohol can be carried out according to a conventional method. For example, the polybasic acid and the polyhydric alcohol are contacted in the presence or absence of an organic solvent and in the presence of a polycondensation catalyst. The process is terminated when the acid value, softening temperature, etc. of the produced polyester reach a predetermined value. Thereby, polyester is obtained. When a methyl esterified product of a polybasic acid is used as a part of the polybasic acid, a demethanol polycondensation reaction is performed. In this polycondensation reaction, for example, the carboxyl group content at the end of the polyester can be adjusted by appropriately changing the mixing ratio of polybasic acid and polyhydric alcohol, the reaction rate, etc., and thus the properties of the resulting polyester are modified. it can. When trimellitic anhydride is used as the polybasic acid, a modified polyester can also be obtained by easily introducing a carboxyl group into the main chain of the polyester. A self-dispersible polyester in water in which a hydrophilic group such as a carboxyl group or a sulfonic acid group is bonded to the main chain and / or side chain of the polyester can also be used. Further, polyester and acrylic resin may be grafted.

  The binder resin preferably has a glass transition temperature of 30 ° C. or higher and 80 ° C. or lower. When the glass transition temperature of the binder resin is less than 30 ° C., blocking in which the toner is thermally aggregated easily occurs inside the image forming apparatus, and storage stability may be lowered. When the glass transfer temperature of the binder resin exceeds 80 ° C., the fixability of the toner to the recording medium is lowered, and there is a possibility that fixing failure occurs.

  As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, and brilliant carmine 6B. Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue colorants include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated products, first sky blue, induslen blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, malachite green lake, final yellow green G, C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. The amount of the colorant used is not particularly limited, but is preferably 5 parts by weight or more and 20 parts by weight or less, more preferably 5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the binder resin.

  The colorant may be used as a master batch in order to uniformly disperse it in the binder resin. Two or more colorants may be used in the form of composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, lower alcohol or the like to two or more colorants, granulating with a general granulator such as a high speed mill, and drying. The masterbatch and composite particles are mixed into the toner composition during dry mixing.

  The pre-treatment mother particles may contain a charge control agent in addition to the binder resin and the colorant. As the charge control agent, a charge control agent for positive charge control and negative charge control commonly used in this field can be used.

  Examples of charge control agents for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, triphenylmethane Derivatives, guanidine salts, amidine salts and the like can be mentioned.

  Charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, metal salts of salicylic acid and its derivatives (metals are metal Chromium, zinc, zirconium, etc.), boron compounds, fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like. A charge control agent can be used individually by 1 type, or can use 2 or more types together as needed. The amount of the charge control agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 parts by weight or more and 3 parts by weight or less with respect to 100 parts by weight of the binder resin.

  The pre-treatment mother particles include a release agent in addition to the binder resin and the colorant. As the release agent, those commonly used in this field can be used, for example, petroleum wax such as paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax (polyethylene wax, polypropylene Wax etc.) and derivatives thereof, low molecular weight polypropylin wax and derivatives thereof, hydrocarbon polymer waxes such as polyolefin polymer wax (low molecular weight polyethylene wax etc.) and derivatives thereof, carnauba wax and derivatives thereof, rice wax and derivatives thereof , Candelilla wax and its derivatives, plant wax such as wood wax, animal wax such as beeswax and whale wax, fatty acid amide, phenol fatty acid ester, etc. Oil-based synthetic waxes, long-chain carboxylic acids and their derivatives, long-chain alcohols and derivatives thereof, silicon-based polymers, such as higher fatty acids. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like. The amount of the release agent used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 to 20 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin. Part by weight, particularly preferably 1.0 to 8.0 parts by weight. Increasing the content of the release agent can increase the exposure amount of the release agent on the surface of the toner base particles, and can quickly exude the release agent to the toner surface during fixing. When the content is excessively large, there arises a problem that the fixing strength of the toner to the recording medium is deteriorated in fixing at a relatively low temperature.

  The pre-treatment mother particles obtained through the pre-treatment mother particle production step S1a preferably have a volume average particle size of 4 μm or more and 8 μm or less. When the volume average particle diameter of the pre-treatment mother particles is 4 μm or more and 8 μm or less, a high-definition image can be stably formed over a long period of time. Further, by reducing the particle size to this range, a high image density can be obtained even with a small amount of adhesion, and the toner consumption can be reduced. If the volume average particle size of the base particles before processing is less than 4 μm, the particle size of the toner base particles becomes too small, and there is a possibility that high charge and low fluidity may occur. When this high charging and low fluidization occur, it becomes impossible to stably supply the toner to the photoreceptor, and there is a possibility that background fogging and a decrease in image density may occur. If the volume average particle diameter of the pre-treatment mother particles exceeds 8 μm, the toner mother particles have a large particle diameter, and the layer thickness of the formed image becomes high, resulting in an image that feels remarkably granular, and a high-definition image cannot be obtained. Not desirable. Further, as the toner base particle size increases, the specific surface area decreases and the toner charge amount decreases. When the charge amount of the toner is small, the toner is not stably supplied to the photoconductor, and there is a possibility that in-machine contamination due to toner scattering occurs.

(Pre-treatment mother particle surface treatment step S1b)
In the pre-treatment mother particle surface treatment step of step S1b, the pre-treatment mother particles are spheroidized using a hot air spheroidizing apparatus, the shape factor SF2 is 110 or more and 135 or less, and the exposure amount of the release agent on the surface Toner base particles having a toner content of 2.3% by weight or more of the total amount of the toner base particles. The shape factor SF2 of the toner base particles is more preferably from 125 to 135, and the exposure amount of the release agent on the surface of the toner base particles is more preferably 2.5% by weight or more of the total amount of the toner base particles.

  By performing the spheronization treatment with hot air in this way, the shape factor SF2 of the toner base particles can be easily controlled, and the surface of the toner base particles can be smoothed. In the subsequent coating step S3, the film thickness is increased. A uniform coating layer can be formed on the surface of the toner base particles, and both the exuding effect of the release agent and the storage stability can be achieved. When the shape factor SF2 exceeds 135, the toner base particles have too many irregularities on the surface, and there is a possibility that a coating layer having a uniform film thickness cannot be stably formed in the subsequent coating step S3. If a coating layer with a uniform film thickness cannot be formed, and there are too thick and too thin parts, it will be difficult for the release agent to bleed out when the film thickness is too thick. Storage stability is insufficient. Further, when the shape factor SF2 is less than 125, it is possible to form a coating layer having a uniform film thickness, but there is a possibility that the cleaning characteristics of the toner obtained through the coating step S3 may be deteriorated. The dispersion diameter of the release agent on the surface of the toner base particles is preferably 300 nm or more.

  Further, when a hot air spheronizing device is used to produce toner mother particles having such a structure, the release agent oozes out to the surface by heat simultaneously with the spheroidizing treatment of the pre-treatment mother particles. The amount of exposure can be increased. If toner base particles having a release agent exposure amount of 2.3% by weight or more are obtained without being processed by a hot-air spheronizer, the content of the release agent in the total toner base material is increased. In this case, however, there arises a problem that the fixing strength of the toner to the recording medium is deteriorated in fixing at a relatively low temperature.

  As the hot-air spheronizing device used for the spheronization treatment with hot air, a commercially available device can be used. For example, a surface reformer, Meteorebom (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.) Can be used.

  In the hot-air spheroidizing device, air is supplied from the secondary air injection nozzle to collide the pre-treatment mother particles with the collision member in order to prevent aggregation of the pre-treatment mother particles before treatment with hot air. The pre-treatment mother particles are spheroidized with hot air to form toner mother particles, and then the toner mother particles are cooled with cooling air to prevent thermal fusion between the toner mother particles. The supply amount of air from the secondary air injection nozzle is preferably 200L or more and 250L or less per minute. If the supply amount of air from the secondary air injection nozzle is too large, the pre-treatment mother particles may be greatly damaged by the collision member, and if the supply amount is too small, the pre-treatment mother particles tend to aggregate. The supply amount of hot air is preferably 700L or more and 1500L or less per minute. If the supply amount of hot air is too large, the pre-treatment mother particles are melted more than necessary, and if it is too small, the pre-treatment mother particles may not be sufficiently spheroidized. The temperature of the hot air is preferably 50 ° C. or higher and 250 ° C. or lower. If the temperature of the hot air is too high, the pre-treatment mother particles melt more than necessary, and if it is too low, the spheroidization treatment of the pre-treatment mother particles takes time. The supply pressure of the cooling air is preferably 0.1 MPa or more and 0.3 MPa or less. If the supply pressure of the cooling air is too high, the toner base particles may not be sufficiently cooled, and if it is too low, it takes time to cool the toner base particles.

  The shape factor SF2 of the toner on which the toner base particles and the coating layer are formed is a value measured according to the following method.

A metal film (Au film, film thickness 0.5 μm) was formed on the surface of the toner base particles by sputtering deposition. From this metal film-coated toner, 200 to 300 samples were randomly extracted at an acceleration voltage of 5 kV and a magnification of 1000 times by a scanning electron microscope (trade name: S-570, manufactured by Hitachi, Ltd.). I took a photo. The electron micrograph data is image-analyzed by image analysis software (trade name: A image-kun, manufactured by Asahi Kasei Engineering Co., Ltd.). Particle analysis parameters of the image analysis software “A image-kun” are: small figure removal area: 100 pixels, shrinkage separation: number of times 1; small figure: 1; number of times: 10, noise removal filter: none, shading: none, result display unit : Μm. The shape factor SF2 is obtained by the following equation (1) from the peripheral length PERI and the graphic area AREA of the particles thus obtained.
SF-2 = {(PERI) ² / AREA} × (100 / 4π) (1)

The toner shape factor SF2 can also be obtained in the same manner as described above.
The shape factor SF2 is a value represented by the above formula (1), and indicates the degree of unevenness of the surface shape of the particles. When the value of the shape factor SF2 is 100, unevenness does not exist on the particle surface, and the unevenness of the particle surface becomes more prominent as the value of the shape factor SF2 increases.

(2) Resin fine particle preparation step S2
In the resin fine particle preparation step in step S2, dried resin fine particles are prepared. Any method may be used as the drying method. For example, dry resin fine particles can be obtained using a method such as hot-air heat receiving drying, conduction heat transfer drying, far-infrared drying, or microwave drying. The resin fine particles are used as a material for forming toner mother particles into a film in the subsequent coating step S3. By using the resin fine particles as a film forming material on the surface of the toner base particles, it is possible to prevent the occurrence of aggregation due to melting of a low melting point component such as a release agent contained in the toner base particles during storage. Further, for example, when the toner base particles are coated by spraying a liquid in which resin fine particles are dispersed, the shape of the resin fine particles remains on the surface of the toner base particles, so that the toner has better cleaning properties than a toner having a smooth surface. Can be obtained.

  The resin fine particles can be obtained, for example, by emulsifying and dispersing a resin, which is a resin fine particle raw material, with a homogenizer or the like. It can also be obtained by polymerization of resin monomer components.

  As the resin used as the resin fine particle raw material, for example, a resin used for a toner material can be used, and examples thereof include polyester, acrylic resin, styrene resin, and styrene-acrylic copolymer. Among the resin exemplified above, the resin fine particles preferably include an acrylic resin and a styrene-acrylic copolymer. Acrylic resins and styrene-acrylic copolymers have many advantages such as light weight and high strength, high transparency, low cost, and easy to obtain materials with uniform particle diameters.

  The resin used as the resin fine particle raw material may be the same type of resin as the binder resin contained in the pre-treatment mother particles, or may be a different type of resin. In this case, it is preferable to use a different type of resin. When a resin of a different type is used as the resin fine particle raw material, the softening temperature of the resin used as the resin fine particle raw material is preferably higher than the softening temperature of the binder resin contained in the pre-treatment mother particles. As a result, the toner manufactured by the manufacturing method of the present embodiment can prevent the toners from fusing together during storage, and can improve storage stability. The softening temperature of the resin used as the resin fine particle raw material is preferably 80 ° C. or higher and 140 ° C. or lower, although it depends on the image forming apparatus in which the toner is used. By using a resin having such a temperature range, a toner having both storage stability and fixing ability can be obtained.

  The resin fine particles are required to have a volume average particle size sufficiently smaller than the average particle size of the toner base particles, and are preferably 0.05 μm or more and 1 μm or less. The volume average particle size of the resin fine particles is more preferably 0.1 μm or more and 0.5 μm or less. When the volume average particle diameter of the resin fine particles is 0.05 μm or more and 1 μm or less, a protrusion having a suitable size is formed on the surface of the coating layer. As a result, the toner manufactured by the manufacturing method of the present embodiment is easily caught by the cleaning blade during cleaning, and the cleaning performance is improved.

(3) Covering step S3
(Toner production equipment)
FIG. 2 is a front view showing the configuration of the toner manufacturing apparatus 201 used in the toner manufacturing method according to the first embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the toner manufacturing apparatus 201 shown in FIG. 2 as seen from the cutting plane line A200-A200. In the covering step in step S3, for example, using the toner manufacturing apparatus 201 shown in FIG. 2, the resin fine particles prepared in the resin fine particle preparing step in step S2 are attached to the toner base particles prepared in the toner mother particle preparing step in step S1. The coating layer is formed on the surface of the toner base particles by a synergistic effect of the circulation in the apparatus and the impact force by stirring.

  The toner manufacturing apparatus 201, which is a rotary stirring device, includes a powder flow path 202, a spraying means 203, a rotary stirring means 204, a temperature adjustment jacket (not shown), a powder input unit 206, and a powder recovery unit 207. It is comprised including. The rotary stirring means 204 and the powder flow path 202 constitute a circulation means.

  The powder channel 202 includes a stirring unit 208 and a powder flow unit 209. The stirring unit 208 is a cylindrical container-like member having an internal space. Openings 210 and 211 are formed in the stirring unit 208 which is a rotary stirring chamber. The opening 210 is formed so as to penetrate the side wall including the surface 208a of the stirring unit 208 in the thickness direction at a substantially central portion of the surface 208a on one side in the axial direction of the stirring unit 208. Further, the opening 211 is formed on the side surface 208b perpendicular to the surface 208a on the one axial side of the stirring unit 208 so as to penetrate the side wall including the side surface 208b of the stirring unit 208 in the thickness direction. The powder flow part 209 that is a circulation pipe has one end connected to the opening 210 and the other end connected to the opening 211. As a result, the internal space of the stirring unit 208 and the internal space of the powder flow unit 209 are communicated to form the powder flow path 202. Through this powder flow path 202, toner base particles, resin fine particles and gas flow. The powder flow path 202 is provided such that the powder flow direction, which is the direction in which the toner base particles and the resin fine particles flow, is a constant direction.

  The rotating stirring means 204 includes a rotating shaft member 218, a disk-shaped rotating disk 219, and a plurality of stirring blades 220. The rotation shaft member 218 has an axis that coincides with the axis of the stirring unit 208 and is formed on the surface 208c on the other side in the axial direction of the stirring unit 208 so as to penetrate the side wall including the surface 208c in the thickness direction. A cylindrical rod-like member provided so as to be inserted through 221 and rotated about an axis by a motor (not shown). The rotating disk 219 is a disk-shaped member that is supported by the rotating shaft member 218 so that its axis coincides with the axis of the rotating shaft member 218 and rotates with the rotation of the rotating shaft member 218. The plurality of stirring blades 220 are supported by the peripheral portion of the turntable 219 and rotate as the turntable 219 rotates.

  The rotating shaft member 218 can be rotated at a peripheral speed of 50 m / sec or more at the outermost periphery. The outermost periphery is a portion of the rotary stirring means 204 having the longest distance from the rotary shaft member 218 in the direction perpendicular to the rotary shaft member 218.

  The spray means 203 is provided in the powder flow portion 209 of the powder flow path 202 at the powder flow portion closest to the opening 211 in the flow direction of the toner base particles and the resin fine particles. The spray means 203 mixes a liquid storage section for storing a liquid, a carrier gas supply section for supplying a carrier gas, a liquid and a carrier gas, and a toner base particle in which the resulting mixture is present in the powder flow path 202 And a two-fluid nozzle that sprays liquid droplets onto the toner base particles. Compressed air or the like can be used as the carrier gas.

  A temperature adjusting jacket (not shown), which is a temperature adjusting means, is provided in at least a part of the outside of the powder flow path 202, and the inside of the powder flow path 202 and the rotary stirring are passed through a cooling medium or a heating medium into the space inside the jacket. The temperature of the means 204 is adjusted to a predetermined temperature. The temperature adjustment jacket is preferably provided on the entire outside of the powder flow path 202. As a result, the adhesion and film formation of the resin fine particles to the toner base particles proceed smoothly, and the adhesion force to the inner wall of the powder flow path is further reduced, so that the toner base particles and the resin fine particles adhere to the inner wall of the powder flow path. And the narrowing of the powder flow channel due to the toner base particles and the resin fine particles can be further suppressed. Therefore, the toner base particles are uniformly coated with the resin fine particles, and the toner excellent in the cleaning property coated with the coating layer can be produced with a higher yield.

  A powder input unit 206 and a powder recovery unit 207 are connected to the powder flow unit 209 of the powder channel 202. FIG. 4 is a front view showing the configuration around the powder input unit 206 and the powder recovery unit 207. The powder input unit 206 includes a hopper (not shown) that supplies toner base particles and resin fine particles, a supply pipe 212 that communicates the hopper and the powder flow path 202, and an electromagnetic valve 213 provided in the supply pipe 212. The toner base particles and resin fine particles supplied from the hopper are supplied to the powder flow path 202 through the supply pipe 212 in a state where the flow path in the supply pipe 212 is opened by the electromagnetic valve 213. The toner base particles and the resin fine particles supplied to the powder flow path 202 flow in a constant powder flow direction by the stirring by the rotary stirring means 204. Further, when the flow path in the supply pipe 212 is closed by the electromagnetic valve 213, the toner base particles and the resin fine particles are not supplied to the powder flow path 202.

  The powder recovery unit 207 includes a recovery tank 215, a recovery pipe 216 that connects the recovery tank 215 and the powder flow path 202, and an electromagnetic valve 217 provided in the recovery pipe 216. In a state where the flow path in the collection pipe 216 is opened by the electromagnetic valve 217, the toner particles flowing through the powder flow path 202 are collected in the collection tank 215 via the collection pipe 216. In addition, when the flow path in the collection pipe 216 is closed by the electromagnetic valve 217, the toner particles flowing through the powder flow path 202 are not collected.

  The toner manufacturing apparatus 201 is not limited to the above-described configuration, and various modifications can be made. For example, the temperature adjustment jacket may be provided on the entire outer surface of the powder flow part 209 and the stirring part 208, or may be provided on a part of the powder flow part 209 or the outside of the stirring part 208. . If a temperature adjustment jacket is provided on the entire surface outside the powder flow section 209 and the stirring section 208, it is possible to more reliably prevent toner base particles from adhering to the inner wall of the powder flow path 202.

  The toner production apparatus as described above can also be obtained by combining a commercially available stirring apparatus and spraying means. As a commercially available stirring apparatus provided with a powder flow path and rotating stirring means, for example, a hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.) and the like can be mentioned. By mounting the liquid spray unit in such a stirring device, this stirring device can be used as a toner manufacturing apparatus used in the toner manufacturing method of the present invention.

  The covering step S3 using the toner manufacturing apparatus 201 as described above includes a temperature adjusting step S3a, a resin fine particle attaching step S3b, a spraying step S3c, a film forming step S3d, and a collecting step S3e.

(Temperature adjustment step S3a)
In the temperature adjustment process of step S3a, while rotating the rotary stirring means 204, the temperature in the powder flow path 202 and the rotary stirring means 204 is adjusted to a predetermined temperature through a medium in a temperature adjustment jacket disposed outside them. To do. As a result, the temperature in the powder flow path 202 can be controlled to be equal to or lower than the temperature at which the toner base particles and resin fine particles introduced in the resin fine particle attaching step S3b described later are not softened and deformed.

(Resin fine particle adhesion step S3b)
In the resin fine particle attaching step of step S3b, the toner base particles and the resin fine particles are supplied from the powder input unit 206 to the powder flow path 202 while the rotary shaft member 218 of the rotary stirring unit 204 is rotating. The toner base particles and resin fine particles supplied to the powder flow path 202 are stirred by the rotary stirring means 204 and flow in the direction of the arrow 214 through the powder flow section 209 of the powder flow path 202. As a result, the resin fine particles adhere to the surface of the toner base particles.

  In the toner base particle preparation step S1, the shape factor SF2 of the toner base particle is adjusted to 110 or more and 135 or less. However, in this step, the toner base particle having a smoothed surface having the shape factor SF2 of 110 or more and 135 or less is used. The resin fine particles can be uniformly adhered to the surface of the toner base particles, and a coating layer having a uniform film thickness can be formed on the surface of the toner base particles through the spraying step S3c and the film forming step S3d.

(Spraying step S3c)
In the spraying process of step S3c, the toner base particles and the resin fine particles that are in a fluid state are sprayed with a carrier gas from the spraying means 203 without causing the particles to dissolve and plasticizing. The spraying means 203 is a two-fluid nozzle. The liquid is fed to the spraying means 203 at a constant flow rate by a liquid feed pump, and the liquid sprayed by the spraying means 203 is gasified, and the gasified liquid spreads on the surface of the toner base particles and the resin fine particles. As a result, the toner base particles and the resin fine particles are plasticized.

  In the present embodiment, it is preferable that the spraying of the liquid from the spraying unit 203 is started after the surface of the toner base particles and the flow rate of the resin fine particles are stabilized in the powder flow path 202. Thereby, since the liquid can be uniformly sprayed on the toner base particles and the resin fine particles, the yield of the toner uniformly coated with the coating layer can be improved.

(Spraying liquid)
The liquid having an effect of plasticizing the toner base particles and the resin fine particles without being dissolved is not particularly limited. However, since the liquid needs to be removed from the toner base particles and the resin fine particles after the liquid is sprayed, the liquid is easily evaporated. It is preferable. Examples of such a liquid include a liquid containing a lower alcohol. Examples of the lower alcohol include methanol, ethanol, propanol and the like. When the liquid contains such a lower alcohol, the wettability of the resin fine particles as the coating material to the toner mother particles can be improved, and the resin fine particles are adhered to the entire surface or most of the toner mother particles, and the deformation and film are further deformed. It becomes easy to make it. Further, since the lower alcohol has a high vapor pressure, the drying time when removing the liquid can be further shortened, and aggregation of the toner base particles can be suppressed.

  The viscosity of the liquid is preferably 5 cP or less. Alcohol is preferable as a liquid having a viscosity of 5 cP or less. Examples of the alcohol include methyl alcohol and ethyl alcohol. Since these alcohols have a low viscosity and are easy to evaporate, the liquid droplets of the liquid sprayed from the spraying means 203 do not become coarse when the liquid contains alcohol, so that the liquid droplets with a fine droplet diameter can be obtained. Spraying becomes possible. In addition, it is possible to spray a liquid having a uniform droplet diameter. At the time of collision between the toner base particles and the liquid droplets, further refinement of the liquid droplets can be promoted. As a result, the toner base particles and the resin fine particle surfaces are uniformly wetted and blended, and the resin fine particles are softened by a synergistic effect with the collision energy, and a coated toner having excellent uniformity can be obtained.

  The viscosity of the liquid is measured at 25 ° C. The viscosity of the liquid can be measured by, for example, a cone plate type rotary viscometer.

  The angle θ formed by the liquid spray direction which is the direction of the axis of the two-fluid nozzle and the powder flow direction which is the direction in which the toner base particles and the resin fine particles flow in the powder flow path 202 is 0 ° or more and 45 ° or less. Preferably there is. When θ is within such a range, liquid droplets are prevented from recoiling at the inner wall of the powder flow path 202, and the yield of toner mother particles coated with a resin film can be further improved. . When the angle θ between the direction of spraying the liquid from the spraying means 203 and the direction of powder flow exceeds 45 °, the liquid droplets are likely to recoil on the inner wall of the powder flow path 202, and the liquid tends to stay. Aggregation of toner particles occurs and the yield deteriorates. The two-fluid nozzle is provided by being inserted through an opening formed in the outer wall of the powder flow path 202.

  Further, the spread angle φ of the liquid sprayed by the two-fluid nozzle is preferably 20 ° or more and 90 ° or less. If the spread angle φ is out of this range, it may be difficult to uniformly spray the liquid onto the toner base particles.

(Filming process)
In the film forming step of step S3d, the resin fine particles are softened and formed into a continuous film by the synergistic effect of the circulation by the toner manufacturing apparatus 201 and the impact force by the stirring and the thermal energy by the stirring, and the resin film is formed on the toner base particles. Stirring of the rotary stirring means 204 is continued at a predetermined temperature until it is formed, and the toner base particles and resin fine particles are caused to flow.

(Recovery process)
In the recovery step of step S3e, the spraying of the liquid from the spraying means 203 is terminated, the rotation of the rotary stirring means 204 is stopped, and the toner on which the coating layer is formed is discharged from the powder recovery unit 207 to the outside of the apparatus. The toner having a coating layer formed on the surface is collected.

  In this way, the toner is manufactured by the manufacturing method of the present invention. In this toner, a coating layer is formed on the surface of the toner base particles. By adjusting the exposure amount of the release agent on the surface of the toner base particles to 2.3% by weight or more of the total amount of the toner base particles, the toner can be promptly fixed. Since the release agent exudes, a toner having a wide fixing non-offset region can be obtained.

  The dispersion diameter of the release agent on the surface of the toner base particles is preferably 300 nm or more. In order for the release agent to act effectively at the time of fixing, it is necessary to exude a certain amount of the release agent from the toner base particles. The parting agent is a part where the toner base particle surface and the parting agent are in contact with each other, that is, the part which is not in contact with the peripheral part of the parting agent exposed on the toner base particle surface. Since the central portion of the toner is more likely to ooze out, a large amount of the release agent can be oozed out of the toner base particles by increasing the dispersion diameter of the release agent on the surface of the toner base particles to some extent. If the dispersion diameter of the release agent on the surface of the toner base particles is 300 nm or more, the release agent exudes more quickly at the time of fixing, so that the fixing non-offset region can be made wider.

(Conditions in coating step S3)
In the covering step S3 including steps S3a to S3e, the peripheral speed of the outermost periphery of the rotary stirring means 204 is preferably set to 30 m / sec or more, and more preferably set to 50 m / sec or more. The outermost periphery of the rotary stirring means 204 is a portion 204a of the rotary stirring means 204 having the longest distance from the axis of the rotary shaft member 218 in the direction perpendicular to the direction in which the rotary shaft member 218 of the rotary stirring means 204 extends. When the peripheral speed at the outermost periphery of the rotating stirring means 204 at the time of rotation is 30 m / sec or more, the toner base particles can be isolatedly flowed. If the peripheral speed at the outermost periphery is less than 30 m / sec, the toner base particles and the resin fine particles cannot be isolatedly flowed, so that the toner base particles cannot be uniformly coated with the resin film.

  In the coating step S3, a temperature adjusting jacket is provided in at least a part of the powder channel 202, and the temperature in the powder channel 202 is set to a predetermined temperature through a cooling medium or a heating medium in the space inside the jacket. It is preferable to adjust. Thereby, in the temperature adjustment step S3a, the temperature inside the powder flow path 202 and outside the rotary stirring means 204 is controlled to be equal to or lower than the temperature at which the toner base particles and resin fine particles charged in the resin fine particle adhesion step S3b are not softened and deformed. Can do. In the spraying step S3c and the film forming step S3d, the temperature applied to the toner base particles, the resin fine particles and the liquid is less varied, and it is possible to maintain a stable fluid state of the toner base particles and the resin fine particles.

  Further, the toner base particles and resin fine particles made of synthetic resin or the like usually collide with the inner wall of the powder flow path 202 many times, and at the time of the collision, a part of the collision energy is converted into thermal energy, and the toner base particles and Accumulated in resin particles. As the number of collisions increases, the thermal energy accumulated in these particles increases, and eventually the toner base particles and resin fine particles soften and adhere to the inner wall of the powder flow path. By adjusting the temperature through the cooling medium or heating medium in the space, it is possible to suppress the adhesion of the toner base particles and the resin fine particles to the inner wall of the powder flow path due to excessive temperature rise, and the liquid sprayed from the spraying means is powdered. It is possible to suppress adhesion of toner base particles and resin fine particles to the powder flow path 202 due to accumulation in the body flow path 202 and blockage in the powder flow path 202 due to the accumulation. Therefore, the toner base particles are uniformly coated with the resin fine particles, and the toner excellent in the cleaning property coated with the coating layer can be produced with high yield.

  In the powder flow section 209 downstream of the spraying means 203, the sprayed liquid remains without being dried, and if the temperature is not appropriate, the drying speed becomes slow and the liquid tends to stay. When the toner base particles come into contact, the toner base particles easily adhere to the inner wall of the powder flow path 202. This can be a source of aggregation of toner base particles. On the inner wall in the vicinity of the opening 210, the toner base particles that flow through the powder flow-through portion 209 and flow into the stirring portion 208 from the opening 210 and the toner base that flows in the stirring portion 208 by stirring by the rotary stirring means 204. Easy to collide with particles. As a result, the collided toner base particles are likely to adhere to the vicinity of the opening 210. Therefore, by providing the temperature adjustment jacket in the portion where the toner base particles are likely to adhere, it is possible to more reliably prevent the toner base particles from adhering to the inner wall of the powder flow path 202.

  The temperature in the powder flow path 202 is set to be equal to or lower than the glass transition temperature of the toner base particles. The temperature in the powder channel 202 is more preferably 30 ° C. or higher and the glass transition temperature of the toner base particles. The temperature in the powder channel 202 becomes substantially uniform in any part in the powder channel 202 due to the flow of the toner mother particles. When the temperature in the powder flow path 202 exceeds the glass transition temperature of the toner base particles, the toner base particles are too soft in the powder flow path 202, and the toner base particles may be aggregated. On the other hand, if the temperature in the powder flow path 202 is lower than 30 ° C., the drying speed of the dispersion may be slowed and productivity may be reduced. Therefore, in order to prevent the aggregation of the toner base particles, the inner diameter is larger than the outer diameter of the powder passage tube in order to maintain the temperature of the powder flow path 202 and the rotary stirring means 204 below the glass transition temperature of the toner base particles. It is necessary to dispose a large temperature adjustment jacket on at least a part of the outside of the powder channel tube and the rotary stirring means 204, and to provide a device having a function of adjusting the temperature through a cooling medium or a heating medium in the space. It is.

  As described above, the rotating stirring unit 204 includes the rotating disk 219 that rotates as the rotating shaft 218 rotates. The toner base particles and the resin fine particles collide with the rotating disk 219 perpendicularly to the rotating disk 219. It is preferable that the rotary disk 219 collides with the rotary shaft member 218 perpendicularly. As a result, the toner base particles and the resin fine particles can be sufficiently stirred rather than the toner base particles and the resin fine particles colliding with the rotating disk 219 in parallel, so that the toner base particles are more uniformly coated with the resin fine particles. And the yield of the toner with the coating layer uniformly coated can be further improved.

  In the present embodiment, the liquid sprayed in the spraying step S3c is preferably gasified so that the inside of the powder channel 202 has a constant gas concentration. As a result, the concentration of the gasified liquid in the powder flow path 202 can be kept constant, and the drying speed of the liquid can be increased as compared with the case where the concentration of the gasified liquid is not kept constant. The toner particles in which the liquid remains can be prevented from adhering to other toner particles, and aggregation of the toner particles can be further suppressed. Therefore, the yield of the toner uniformly coated with the coating layer can be further improved.

  The concentration of the gasified liquid measured by the concentration sensor in the gas discharge unit 222 is preferably about 3% or less. Since the concentration of the gasified liquid is about 3% or less, the drying speed of the liquid can be sufficiently increased, so that the undried toner base particles in which the liquid remains are replaced with other toner base particles. Adhesion can be prevented and aggregation of toner mother particles can be prevented. In the gas discharge part 222, the concentration of the gasified liquid is more preferably 0.1% or more and 3.0% or less by the concentration sensor. When the spraying speed is within such a range, aggregation of toner base particles can be prevented without reducing productivity.

  The gasified liquid is preferably discharged out of the powder channel through the through hole 221 so that the gas concentration in the powder channel 202 is constant. As a result, the concentration of the gasified liquid in the powder flow path 202 can be kept constant, and the drying speed of the liquid can be increased as compared with the case where the concentration of the gasified liquid is not kept constant. The toner particles in which the liquid remains can be prevented from adhering to other toner particles, and aggregation of the toner particles can be further suppressed. Therefore, the yield of the toner uniformly coated with the coating layer can be further improved.

2. Toner The toner according to the second embodiment of the present invention is manufactured by the toner manufacturing method according to the first embodiment. Since the toner obtained by the toner manufacturing method of the first embodiment has a uniform coating amount of the coating material, toner characteristics such as charging characteristics between individual toner particles are uniform. Further, the toner has a coating layer having a uniform film thickness. Further, since the release agent exudes quickly at the time of fixing, it has a wide fixing non-offset region. When an image is formed using such a toner, a high-definition image having good image quality with no density unevenness can be obtained.

  An external additive may be added to the toner of the present invention. Known external additives can be used, and examples thereof include silica and titanium oxide. These are preferably surface-treated with a silicon resin, a silane coupling agent or the like. The amount of the external additive used is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the toner.

3. Developer The developer according to the third embodiment of the present invention includes the toner according to the second embodiment. As a result, a developer having uniform toner characteristics such as charging characteristics between individual toner particles can be obtained, so that a developer capable of maintaining good developability can be obtained. The developer of this embodiment can be used as a one-component developer or a two-component developer. When used as a one-component developer, the toner is used alone without using a carrier. When used as a one-component developer, a blade and a fur brush are used, and the toner is conveyed by friction charging with a developing sleeve to adhere the toner onto the sleeve, thereby forming an image. When used as a two-component developer, the toner of the second embodiment is used together with a carrier. Since the toner of the present invention has uniform toner characteristics such as charging characteristics between individual toner particles, it is possible to stably form a high-definition and good-quality image without uneven density.

(Career)
As the carrier, a known carrier can be used. For example, a resin-coated carrier or a resin in which iron or copper, zinc, nickel, cobalt, manganese, chromium or the like alone or a composite ferrite and carrier core particles are coated with a coating material. And a resin-dispersed carrier in which magnetic particles are dispersed. Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicon resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin , Polyamide, polyvinyl butyral, nigrosine, amino acrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like. Moreover, although it does not restrict | limit especially as resin used for a resin dispersion type carrier, For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin, etc. are mentioned. Either of them is preferably selected according to the toner component, and one kind can be used alone or two or more kinds can be used in combination.

The shape of the carrier is preferably a spherical shape or a flat shape. The particle size of the carrier is not particularly limited, but is preferably 10 to 100 μm, more preferably 20 to 50 μm, considering high image quality. Furthermore, the resistivity of the carrier is preferably 10 ⁸ Ω · cm or more, more preferably 10 ¹² Ω · cm or more.

The volume resistivity of the carrier is determined by placing the carrier in a container having a cross-sectional area of 0.50 cm ² and tapping, then applying a load of 1 kg / cm ² to the particles packed in the container, This is a value obtained by reading a current value when a voltage generating an electric field of 1000 V / cm is applied. When the volume resistivity is low, when a bias voltage is applied to the developing sleeve, charges are injected into the carrier, and carrier particles easily adhere to the photoreceptor. Further, breakdown of the bias voltage is likely to occur.

  The magnetization strength (maximum magnetization) of the carrier is preferably 10 to 60 emu / g, more preferably 15 to 40 emu / g. The magnetization strength depends on the magnetic flux density of the developing roller, but under the general magnetic flux density conditions of the developing roller, if it is less than 10 emu / g, the magnetic binding force does not work and causes carrier scattering. There is a fear. On the other hand, if the magnetization strength exceeds 60 emu / g, the rising of the carrier becomes too high, so that it is difficult to maintain the non-contact state with the image carrier in the non-contact development. Further, in the contact development, there is a risk that a sweep is likely to appear in the toner image.

The use ratio of the toner and the carrier in the two-component developer is not particularly limited and can be appropriately selected according to the kind of the toner and the carrier. However, if a resin-coated carrier (density 5 to 8 g / cm ² ) is taken as an example, the development is performed. The toner may be used so that the toner is contained in 2 to 30% by weight, preferably 2 to 20% by weight of the total amount of the developer. In the two-component developer, the carrier coverage with the toner is preferably 40 to 80%.

4. Image Forming Apparatus FIG. 5 is a cross-sectional view schematically showing a configuration of an image forming apparatus 100 according to the fourth embodiment of the present invention. The image forming apparatus 100 is a multifunction machine having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on a recording medium in accordance with transmitted image information. That is, the image forming apparatus 100 has three types of printing modes, ie, a copier mode (copying mode), a printer mode, and a FAX mode. Operation input from an operation unit (not shown), personal computer, portable terminal device, information A print mode is selected by a control unit (not shown) in response to reception of a print job from an external device using a recording storage medium or a memory device.

  The image forming apparatus 100 includes a photosensitive drum 11 that is an image carrier, an image forming unit 2, a transfer unit 3, a fixing unit 4, a recording medium supply unit 5, and a discharge unit 6. Each member constituting the image forming unit 2 and some members included in the transfer unit 3 are black (b), cyan (c), magenta (m) and yellow (y) included in the color image information. In order to correspond to image information, four each are provided. Here, each member provided by four according to each color is distinguished by attaching an alphabet representing each color to the end of the reference symbol, and when referring collectively, only the reference symbol is used.

  The image forming unit 2 includes a charging unit 12, an exposure unit 13, a developing device 14, and a cleaning unit 15. The charging unit 12 and the exposure unit 13 function as a latent image forming unit. The charging unit 12, the developing device 14, and the cleaning unit 15 are arranged around the photosensitive drum 11 in this order. The charging unit 12 is disposed below the developing device 14 and the cleaning unit 15 in the vertical direction.

The photosensitive drum 11 is a roller-like member that is provided so as to be rotatable about an axis by a rotation driving unit (not shown), and on which an electrostatic latent image is formed. The rotation driving means of the photosensitive drum 11 is controlled by a control means realized by a central processing unit (CPU). The photosensitive drum 11 includes a conductive substrate (not shown) and a photosensitive layer (not shown) formed on the surface of the conductive substrate. The conductive substrate can take various shapes, and examples thereof include a cylindrical shape, a columnar shape, and a thin film sheet shape. Among these, a cylindrical shape is preferable. The conductive substrate is formed of a conductive material.

  As the conductive material, those commonly used in this field can be used. For example, metals such as aluminum, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum, etc. A conductive layer made of one or more of aluminum, aluminum alloy, tin oxide, gold and indium oxide is formed on a film-like substrate such as two or more alloys, synthetic resin film, metal film or paper. And a resin composition containing conductive particles and / or a conductive polymer. As the film-like substrate used for the conductive film, a synthetic resin film is preferable, and a polyester film is particularly preferable. Moreover, as a formation method of the electroconductive layer in an electroconductive film, vapor deposition, application | coating, etc. are preferable.

  The photosensitive layer is formed, for example, by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. In that case, it is preferable to provide an undercoat layer between the conductive substrate and the charge generation layer or the charge transport layer. By providing an undercoat layer, it is possible to cover the scratches and irregularities present on the surface of the conductive substrate, smooth the surface of the photosensitive layer, and prevent deterioration of the chargeability of the photosensitive layer during repeated use. And / or the advantage of improving the charging characteristics of the photosensitive layer in a low humidity environment can be obtained. Further, a laminated photoreceptor having a three-layer structure having a high durability and having a photoreceptor surface protective layer as the uppermost layer may be used.

  The charge generation layer is mainly composed of a charge generation material that generates a charge when irradiated with light, and contains a known binder resin, plasticizer, sensitizer and the like as necessary. As the charge generation material, those commonly used in this field can be used, for example, perylene pigments such as perylene imide and perylene acid anhydride, polycyclic quinone pigments such as quinacridone and anthraquinone, metal and metal-free phthalocyanines, and halogenated compounds. Phthalocyanine pigments such as metal-free phthalocyanine, squalium dye, azulenium dye, thiapyrylium dye, carbazole skeleton, styryl stilbene skeleton, triphenylamine skeleton, dibenzothiophene skeleton, oxadiazole skeleton, fluorenone skeleton, bis-stilbene skeleton, distyryl And azo pigments having an oxadiazole skeleton or a distyrylcarbazole skeleton. Among these, metal-free phthalocyanine pigments, oxotitanyl phthalocyanine pigments, bisazo pigments containing a fluorene ring and / or a fluorenone ring, bisazo pigments composed of aromatic amines, trisazo pigments, etc. have high charge generation ability and high sensitivity. Suitable for obtaining a photosensitive layer. One type of charge generating material can be used alone, or two or more types can be used in combination. Although the content of the charge generation material is not particularly limited, it is preferably 5 parts by weight or more and 500 parts by weight or less, more preferably 10 parts by weight or more and 200 parts by weight or less with respect to 100 parts by weight of the binder resin in the charge generation layer. is there. As the binder resin for the charge generation layer, those commonly used in this field can be used. For example, melamine resin, epoxy resin, silicone resin, polyurethane, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate, phenoxy resin , Polyvinyl butyral, polyarylate, polyamide and polyester. Binder resin can be used individually by 1 type, or can use 2 or more types together as needed.

  The charge generation layer generates charge by dissolving or dispersing appropriate amounts of charge generation materials, binder resins and, if necessary, plasticizers and sensitizers in an appropriate organic solvent that can dissolve or disperse these components. It can be formed by preparing a layer coating solution, applying this charge generation layer coating solution to the surface of the conductive substrate, and drying the surface of the conductive substrate. The film thickness of the charge generation layer thus obtained is not particularly limited, but is preferably 0.05 μm or more and 5 μm or less, more preferably 0.1 μm or more and 2.5 μm or less.

  The charge transport layer laminated on the charge generation layer has a charge transport material having the ability to accept and transport the charge generated from the charge generation material and a binder resin for the charge transport layer as essential components. Contains known antioxidants, plasticizers, sensitizers, lubricants and the like. As the charge transport material, those commonly used in this field can be used, for example, poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, Polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline Derivatives, phenylhydrazones, hydrazone derivatives, triphenylamine compounds, tetraphenyldiamine compounds, triphenylmethane compounds, stilbene compounds, 3-methyl-2-benzothiazoli Electron donating substances such as azine compounds having a ring, fluorenone derivatives, dibenzothiophene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo [c] cinnoline derivatives, phenazine oxide derivatives, tetra And electron accepting substances such as cyanoethylene, tetracyanoquinodimethane, promanyl, chloranil, and benzoquinone. The charge transport materials can be used alone or in combination of two or more. Although the content of the charge transport material is not particularly limited, it is preferably 10 parts by weight or more and 300 parts by weight or less, more preferably 30 parts by weight or more and 150 parts by weight or less with respect to 100 parts by weight of the binder resin in the charge transport material. .

  As the binder resin for the charge transport layer, those commonly used in this field and capable of uniformly dispersing the charge transport material can be used. For example, polycarbonate, polyarylate, polyvinyl butyral, polyamide, polyester, polyketone, epoxy resin, polyurethane , Polyvinyl ketone, polystyrene, polyacrylamide, phenol resin, phenoxy resin, polysulfone resin, and copolymer resins thereof. Among these, in consideration of film formability, wear resistance of the resulting charge transport layer, electrical characteristics, etc., polycarbonate containing bisphenol Z as a monomer component (hereinafter referred to as “bisphenol Z type polycarbonate”), bisphenol Z type polycarbonate A mixture of and other polycarbonates is preferred. Binder resin can be used individually by 1 type, or can use 2 or more types together.

  The charge transport layer preferably contains an antioxidant together with the charge transport material and the binder resin for the charge transport layer. As the antioxidant, those commonly used in this field can be used, and examples thereof include vitamin E, hydroquinone, hindered amine, hindered phenol, paraphenylenediamine, arylalkane and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. It is done. One antioxidant can be used alone, or two or more antioxidants can be used in combination. The content of the antioxidant is not particularly limited, but is 0.01% by weight or more and 10% by weight or less, preferably 0.05% by weight or more and 5% by weight or less of the total amount of components constituting the charge transport layer.

  The charge transport layer is dissolved or dispersed in a suitable organic solvent capable of dissolving or dispersing these components, such as a charge transport material, a binder resin, and if necessary, an antioxidant, a plasticizer, and a sensitizer. The charge transport layer coating liquid is prepared, the charge transport layer coating liquid is applied to the surface of the charge generation layer, and the charge generation layer surface is dried. The film thickness of the charge transport layer thus obtained is not particularly limited, but is preferably 10 μm or more and 50 μm or less, more preferably 15 μm or more and 40 μm or less.

  A photosensitive layer in which a charge generation material and a charge transport material are present can be formed in one layer. In that case, the type, content, binder resin, and other additives of the charge generation material and the charge transport material may be the same as in the case of separately forming the charge generation layer and the charge transport layer.

  In this embodiment, the photosensitive drum formed by forming the organic photosensitive layer using the charge generation material and the charge transport material as described above is used. Instead, an inorganic photosensitive layer using silicon or the like is formed. A photosensitive drum can be used.

  The charging unit 12 faces the photosensitive drum 11 and is arranged so as to be separated from the surface of the photosensitive drum 11 along the longitudinal direction of the photosensitive drum 11 with a gap, and the surface of the photosensitive drum 11 has a predetermined polarity and Charge to potential. As the charging unit 12, a charging brush type charger, a charger type charger, a sawtooth type charger, an ion generator, or the like can be used. In the present embodiment, the charging unit 12 is provided so as to be separated from the surface of the photosensitive drum 11, but is not limited thereto. For example, a charging roller may be used as the charging unit 12 and the charging roller may be disposed so that the charging roller and the photosensitive drum 11 are in pressure contact with each other, or a contact charging type charger such as a charging brush or a magnetic brush may be used. Good.

  The exposure unit 13 is arranged such that light of each color information emitted from the exposure unit 13 passes between the charging unit 12 and the developing device 14 and is irradiated on the surface of the photosensitive drum 11. The exposure unit 13 branches the image information into light of each color information of black, cyan, magenta, and yellow in the unit, and the surface of the photosensitive drum 11 charged to a uniform potential by the charging unit 12 is light of each color information. To form an electrostatic latent image on the surface. As the exposure unit 13, for example, a laser scanning unit including a laser irradiation unit and a plurality of reflecting mirrors can be used. In addition, a unit in which an LED array or a liquid crystal shutter and a light source are appropriately combined may be used.

  The cleaning unit 15 uses the developing device 14 to transfer the toner image formed on the surface of the photosensitive drum 11 to a recording medium, and then removes the toner remaining on the surface of the photosensitive drum 11 to remove the surface of the photosensitive drum 11. Clean. For the cleaning unit 15, for example, a plate-like member such as a cleaning blade is used. In the image forming apparatus of the present embodiment, an organic photosensitive drum is used as the photosensitive drum 11, and the surface of the organic photosensitive drum is mainly composed of a resin component, and thus is generated by corona discharge by a charging device. Deterioration of the surface of the organic photosensitive drum is likely to proceed due to the chemical action of ozone. However, the deteriorated surface portion is worn by receiving the rubbing action by the cleaning unit 15, and the gradually deteriorated surface portion is surely removed. Therefore, the problem of surface deterioration due to ozone or the like is practically solved, and the charging potential by the charging operation can be stably maintained over a long period of time. Although the cleaning unit 15 is provided in this embodiment, the present invention is not limited to this, and the cleaning unit 15 may not be provided.

  According to the image forming unit 2, the surface of the photosensitive drum 11 that is uniformly charged by the charging unit 12 is irradiated with signal light according to image information from the exposure unit 13 to form an electrostatic latent image. Then, the toner is supplied from the developing device 14 to form a toner image. After the toner image is transferred to the intermediate transfer belt 25, the toner remaining on the surface of the photosensitive drum 11 is removed by the cleaning unit 15. This series of toner image forming operations is repeatedly executed to form an image.

  The transfer means 3 is arranged above the photosensitive drum 11 and has four intermediate portions corresponding to the intermediate transfer belt 25, the drive roller 26, the driven roller 27, and the image information of each color of black, cyan, magenta and yellow. A transfer roller 28, a transfer belt cleaning unit 29, and a transfer roller 30 are included. The intermediate transfer belt 25 is an endless belt-like member that is stretched around a driving roller 26 and a driven roller 27 to form a loop-shaped movement path, and is driven to rotate in the direction of an arrow B. The driving roller 26 is provided so as to be rotatable around its axis by driving means (not shown), and the intermediate transfer belt 25 is driven to rotate in the direction of arrow B by the rotational driving. The driven roller 27 is provided so as to be able to be driven and rotated by the rotational drive of the driving roller 26, and applies a certain tension to the intermediate transfer belt 25 so that the intermediate transfer belt 25 does not loosen. The intermediate transfer roller 28 is provided in pressure contact with the photosensitive drum 11 via the intermediate transfer belt 25 and capable of being driven to rotate about its axis by a driving unit (not shown). The intermediate transfer roller 28 is connected to a power source (not shown) for applying a transfer bias as described above, and has a function of transferring the toner image on the surface of the photosensitive drum 11 to the intermediate transfer belt 25.

  When the intermediate transfer belt 25 passes through the photoconductive drum 11 while being in contact with the photoconductive drum 11, the toner on the surface of the photoconductive drum 11 is transferred from the intermediate transfer roller 28 disposed opposite to the photoconductive drum 11 through the intermediate transfer belt 25. A transfer bias having a polarity opposite to the charging polarity is applied, and the toner image formed on the surface of the photosensitive drum 11 is transferred to the intermediate transfer belt 25. In the case of a full-color image, each color toner image formed on each photoconductor drum 11 is sequentially transferred onto the intermediate transfer belt 25 to form a full-color toner image.

  The transfer belt cleaning unit 29 is provided so as to face the driven roller 27 through the intermediate transfer belt 25 and to contact the outer peripheral surface of the intermediate transfer belt 25. The toner adhering to the intermediate transfer belt 25 due to contact with the photosensitive drum 11 causes the recording medium to be contaminated. Therefore, the transfer belt cleaning unit 29 removes and collects the toner on the surface of the intermediate transfer belt 25.

  The transfer roller 30 is provided in pressure contact with the drive roller 26 via the intermediate transfer belt 25, and can be driven to rotate about an axis by a drive unit (not shown). The toner image carried on the intermediate transfer belt 25 and conveyed at the pressure contact portion between the transfer roller 30 and the driving roller 26, that is, the transfer nip portion, is transferred to a recording medium fed from a recording medium supply means 5 described later. The The recording medium carrying the toner image is fed to the fixing unit 4.

  According to the transfer unit 3, the toner image transferred from the photosensitive drum 11 to the intermediate transfer belt 25 at the pressure contact portion between the photosensitive drum 11 and the intermediate transfer roller 28 rotates the intermediate transfer belt 25 in the arrow B direction. It is conveyed to a transfer nip portion by driving, and transferred to a recording medium there.

  The fixing unit 4 is provided downstream of the transfer unit 3 in the conveyance direction of the recording medium, and includes a fixing roller 31 and a pressure roller 32. The fixing roller 31 is rotatably provided by a driving unit (not shown), and fixes an unfixed toner image carried on the recording medium to the recording medium by heating and melting the constituent toner. A heating unit (not shown) is provided inside the fixing roller 31. The heating unit heats the fixing roller 31 so that the surface of the fixing roller 31 reaches a predetermined temperature (hereinafter also referred to as “heating temperature”). For example, a heater or a halogen lamp can be used as the heating means. The heating means is controlled by fixing condition control means described later. The control of the heating temperature by the fixing condition control means will be described in detail later.

  A temperature detection sensor (not shown) is provided near the surface of the fixing roller 31, and the temperature detection sensor detects the surface temperature of the fixing roller 31. The detection result by the temperature detection sensor is written in the storage unit of the control means described later. The pressure roller 32 is provided so as to be in pressure contact with the fixing roller 31 and is supported so as to be driven to rotate by the rotation drive of the pressure roller 32. When the toner is melted by heat from the fixing roller 31 and the toner image is fixed on the recording medium, the pressure roller 32 presses the toner and the recording medium to assist the fixing of the toner image onto the recording medium. A pressure contact portion between the fixing roller 31 and the pressure roller 32 is a fixing nip portion.

  According to the fixing unit 4, the recording medium onto which the toner image is transferred by the transfer unit 3 is sandwiched between the fixing roller 31 and the pressure roller 32, and the toner image is recorded under heating when passing through the fixing nip portion. By being pressed against the medium, the toner image is fixed on the recording medium and an image is formed.

  The recording medium supply unit 5 includes an automatic paper feed tray 35, a pickup roller 36, a transport roller 37, a registration roller 38, and a manual paper feed tray 39. The automatic paper feed tray 35 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores a recording medium. Examples of the recording medium include plain paper, color copy paper, overhead projector sheet, and postcard. The pick-up roller 36 takes out the recording medium stored in the automatic paper feed tray 35 one by one and feeds it to the paper transport path S1. The conveyance rollers 37 are a pair of roller members provided so as to be in pressure contact with each other, and convey the recording medium toward the registration rollers 38. The registration rollers 38 are a pair of roller members provided so as to be in pressure contact with each other, and the recording medium fed from the conveyance roller 37 is used to convey the toner image carried on the intermediate transfer belt 25 to the transfer nip portion. Synchronously, it is fed to the transfer nip. The manual paper feed tray 39 is a device for taking a recording medium into the image forming apparatus 100 by a manual operation. The recording medium taken from the manual paper feed tray 39 passes through the paper conveyance path S2 by the conveyance roller 37. Then, it is fed to the registration roller 38. According to the recording medium supply means 5, the toner image carried on the intermediate transfer belt 25 is conveyed to the transfer nip portion of the recording medium supplied one by one from the automatic paper feed tray 35 or the manual paper feed tray 39. In synchronism with this, the sheet is fed to the transfer nip portion.

  The discharge unit 6 includes a conveyance roller 37, a discharge roller 40, and a discharge tray 41. The conveyance roller 37 is provided downstream of the fixing nip portion in the sheet conveyance direction, and conveys the recording medium on which the image is fixed by the fixing unit 4 toward the discharge roller 40. The discharge roller 40 discharges the recording medium on which the image is fixed to a discharge tray 41 provided on the upper surface in the vertical direction of the image forming apparatus 100. The discharge tray 41 stores a recording medium on which an image is fixed.

  The image forming apparatus 100 includes a control unit (not shown). For example, the control unit is provided in an upper part of the internal space of the image forming apparatus 100 and includes a storage unit, a calculation unit, and a control unit. The storage unit of the control unit stores various setting values via an operation panel (not shown) arranged on the upper surface of the image forming apparatus 100, detection results from sensors (not shown) arranged at various locations inside the image forming apparatus 100, and external Image information from the device is input. In addition, programs for executing various means are written. Examples of the various means include a recording medium determination unit, an adhesion amount control unit, and a fixing condition control unit. As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). As the external device, an electric / electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100 can be used. For example, a computer, a digital camera, a television, a video recorder, a DVD recorder HD DVD, Blu-ray disc recorder, facsimile device, portable terminal device and the like. The arithmetic unit takes out various data (image formation command, detection result, image information, etc.) written in the storage unit and programs of various means, and performs various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control. The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor or the like provided with a central processing unit (CPU). The control means includes a main power supply together with the processing circuit described above, and the power supply supplies power not only to the control means but also to each device in the image forming apparatus 100.

5. Fixing Device FIG. 6 is a schematic view schematically showing the developing device 14 provided in the image forming apparatus 100 shown in FIG. The developing device 14 includes a developing tank 20 and a toner hopper 21. The developing tank 20 is disposed so as to face the surface of the photosensitive drum 11, and supplies and develops a toner to an electrostatic latent image formed on the surface of the photosensitive drum 11 to form a visible toner image. It is a shaped member. The developing tank 20 accommodates toner in its internal space and accommodates roller members such as the developing roller 50, the supply roller 51, and the stirring roller 52, and rotatably supports them. Moreover, you may accommodate a screw member instead of a roller-shaped member. The developing device 14 of this embodiment stores the toner of the above-described embodiment in the developing tank 20 as toner.

  An opening 53 is formed on a side surface of the developing tank 20 facing the photosensitive drum 11, and a developing roller 50 is rotatably provided at a position facing the photosensitive drum 11 through the opening 53. The developing roller 50 is a roller-like member that supplies toner to the electrostatic latent image on the surface of the photoconductor 11 at the pressure contact portion or the closest portion with the photoconductor drum 11. When supplying the toner, a potential having a polarity opposite to the charging potential of the toner is applied to the surface of the developing roller 50 as a developing bias voltage (hereinafter simply referred to as “developing bias”). As a result, the toner on the surface of the developing roller 50 is smoothly supplied to the electrostatic latent image. Further, by changing the developing bias value, the toner amount supplied to the electrostatic latent image, that is, the toner adhesion amount of the electrostatic latent image can be controlled.

  The supply roller 51 is a roller-like member that faces the developing roller 50 and can be driven to rotate, and supplies toner around the developing roller 50.

  The agitation roller 52 is a roller-like member provided so as to be able to be driven to rotate while facing the supply roller 51, and feeds toner newly supplied from the toner hopper 21 into the developing tank 20 to the periphery of the supply roller 51. The toner hopper 21 is provided so that a toner replenishing port 54 provided at the lower part in the vertical direction and a toner receiving port 55 provided at the upper part in the vertical direction of the developing tank 20 communicate with each other. Add toner. Further, the toner may be directly supplied from each color toner cartridge without using the toner hopper 21.

  As described above, since the developing device 14 develops a latent image using the developer of the present invention, a high-definition toner image can be stably formed on the photosensitive drum 11. Therefore, a high-quality image can be stably formed.

  Further, according to the present invention, the photosensitive drum 11 on which the latent image is formed, the charging unit 12 and the exposure unit 13 that form the latent image on the photosensitive drum 11, and the high-definition toner image as described above are photosensitive. The image forming apparatus 100 includes the developing device 14 of the present invention that can be formed on the body drum 11. By forming an image with such an image forming apparatus 100, it is possible to stably form a high-definition and high-quality image without density unevenness.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. The glass transition temperature of the binder resin and toner base particles, the softening temperature of the binder resin, the melting point of the release agent, and the volume average particle size of the toner base particles in Examples and Comparative Examples were measured as follows.

[Glass transition temperature of binder resin and pre-treatment mother particles]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample was heated at a heating rate of 10 ° C. per minute and a DSC curve was measured. did. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent was determined as the glass transition temperature (Tg).

[Softening temperature of binder resin]
In a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), a load of 20 kgf / cm ² (9.8 × 10 ⁵ Pa) was applied to give 1 g of a sample (nozzle diameter 1 mm, length). 1 mm), and heated at a heating rate of 6 ° C. per minute. The temperature at which half of the sample flowed out from the die was determined and used as the softening temperature (Tm).

[Melting point of release agent]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), 1 g of the sample is heated from a temperature of 20 ° C. to 200 ° C. at a heating rate of 10 ° C. per minute, and then rapidly cooled from 200 ° C. to 20 ° C. The operation was repeated twice and the DSC curve was measured. The temperature at the top of the endothermic peak corresponding to the melting of the DSC curve measured in the second operation was determined as the melting point of the release agent.

[Volume average particle diameter]
20 ml of a sample and 1 ml of sodium alkyl ether sulfate are added to 50 ml of an electrolytic solution (trade name: ISOTON-II, manufactured by Beckman Coulter, Inc.), and an ultrasonic dispersion device (trade name: desktop type dual frequency ultrasonic cleaner VS-D100). (Manufactured by As One Co., Ltd.) for 3 minutes at an ultrasonic frequency of 20 kHz to prepare a measurement sample. This sample for measurement was measured using a particle size distribution measuring device (trade name: Multisizer 3, manufactured by Beckman Coulter, Inc.) under the conditions of aperture diameter: 100 μm, number of measured particles: 50000 count, and volume particle size distribution of sample particles. From this, the volume average particle size was determined.

[Exposure amount of release agent on toner mother particle surface]
1 g of toner base particles are dispersed in 20 ml of hexane, stirred for 10 minutes with a stirrer to elute the release agent on the surface of the toner base particles with hexane, filtered, and put in a dryer set at 40 ° C. overnight. Dried. The operation of heating 1 g of the toner mother particles from a temperature of 20 ° C. to 150 ° C. at a heating rate of 10 ° C. per minute and then rapidly cooling the toner from 150 ° C. to 20 ° C. was repeated twice to measure the DSC curve. The heat capacity of the release agent in the toner base particles was calculated from the heat of fusion of the DSC curve measured in the second operation. The heat capacity of toner base particles not treated with hexane was calculated in the same manner. From the difference between these heat capacities, the exposure amount of the release agent on the surface of the toner base particles was estimated.

[Dispersion diameter of release agent on toner mother particle surface]
Put 100 parts of n-hexane (manufactured by Kishida Chemical Co., Ltd.) and a stir bar in a 2 L beaker, stir with a stirrer, put 5 parts by weight of toner base particles in the beaker, and place an ultrasonic vibrating rod in the beaker. The mold release agent exposed on the surface of the toner base particles was removed by stirring for 10 seconds while dipping and vibrating at 28 kHz. Thereafter, the dispersion liquid in which the toner base particles in the beaker are dispersed is suction filtered, and the toner base particles remaining on the filter paper are dried in a constant temperature and humidity chamber at 35 ° C. and 5% RH. A metal film (Au film, film thickness 0.5 μm) was formed on the surface of the dried toner base particles by sputtering deposition. Using a scanning electron microscope (trade name: VE9800, manufactured by Keyence Corporation), the metal film-coated toner base particles on which the metal film was formed were photographed at an acceleration voltage of 10 kV and a magnification of 1000 times. Toner base particles are obtained by randomly extracting 200 to 300 holes after removing the release agent from the electron micrograph data and analyzing the image with image analysis software (trade name: A Image-kun, manufactured by Asahi Kasei Engineering Co., Ltd.). The diameter of the hole of the release agent on the surface was determined, and this was used as the dispersion diameter of the release agent on the surface of the toner base particles. The size of the dispersion of the release agent on the surface of the toner base particles measured in this way is different from the size of the dispersion of the release agent contained in the toner base particles. The dispersion diameter is larger than the dispersion diameter of the release agent contained in the toner base particles. The larger the dispersion diameter of the release agent on the surface of the toner base particles, the more the release agent oozes out in the pre-treatment base particle surface treatment step S1b.

Example 1
[Pretreatment mother particle preparation step S1a]
The pre-treatment mother particle raw material and the amount added are as follows.
Polyester resin (trade name: Diacron, manufactured by Mitsubishi Rayon Co., Ltd., glass transition temperature 55 ° C., softening temperature 130 ° C.) 87.5% (100 parts)
・ C. I. Pigment Blue 15: 3 5.0% (5.7 parts)
Release agent (paraffin wax, melting point 75 ° C.) 6.0% (6.9 parts)
・ Charge control agent (trade name: Bontron E84, Orient Chemical Co., Ltd.)
1.5% (1.7 parts)

  Each component described above was premixed with a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.). Then, it knead | mixed and kneaded at 140 degreeC using the Nidex (brand name, Mitsui Mining Co., Ltd. product). This melt-kneaded product is coarsely pulverized by a cutting mill (trade name: VM-16, manufactured by Orient Co., Ltd.), then finely pulverized by a jet mill (manufactured by Hosokawa Micron Co., Ltd.), and further by an air classifier (manufactured by Hosokawa Micron Co., Ltd.). By classifying, pre-treatment mother particles having a volume average particle diameter of 6.5 μm and a glass transition temperature of 56 ° C. were produced.

[Pre-treatment mother particle surface treatment step S1b]
Toner mother particles were obtained by spheronizing the surface of the mother particles before treatment using a hot air spheronizing device (trade name: Meteole Inbo, manufactured by Nippon Pneumatic Industry Co., Ltd.). The conditions for the spheronization treatment are as follows: the amount of pre-treatment mother particles charged into the hot air spheronizer is 3.0 kg / hour, the hot air supply rate is 900 L / min, the hot air temperature is 190 ° C., and the cooling air supply The pressure was 0.15 MPa, and the amount of air supplied from the secondary air injection nozzle was 230 L / min. The distance between the cooling air intake and the collision member was 2.0 cm. The resulting toner base particles had a shape factor SF2 of 122.

[Resin fine particle preparation step S2]
A polymer obtained by polymerizing styrene and butyl acrylate is freeze-dried, and the resin fine particles are styrene-butyl acrylate copolymer fine particles A having a volume average particle size of 0.1 μm (glass transition temperature 72 ° C., softening temperature 126 ° C.). Got.

[Coating step S3]
A state in which the toner base particles and the resin fine particles are stirred and fluidized by a device in which a two-fluid nozzle is attached to a hybridization system (trade name: NHS-1 type, manufactured by Nara Machinery Co., Ltd.) according to the device shown in FIG. And sprayed with ethanol as a liquid. As the liquid spray unit, a commercially available product can be used. For example, the liquid is passed through a liquid feed pump (trade name: SP11-12, manufactured by Flume Corporation) and a two-fluid nozzle (trade name: HM-6 type, Fuso Seiki Co., Ltd.) It is possible to use one that is connected so as to deliver a fixed amount of liquid. The spraying speed of liquid and the discharge speed of liquid gas can be observed using a commercially available gas detector (trade name: XP-3110, manufactured by Shin Cosmos Electric Co., Ltd.).

The temperature adjusting jacket was provided on the entire surface of the powder flow section and the stirring section wall. A temperature sensor was attached to the powder channel. The temperature of the powder flow part and the stirring part was adjusted to 55 ° C. In the apparatus, the peripheral speed at the outermost periphery of the rotating stirring means of the hybridization system was set to 100 m / sec in the resin fine particle adhering step to the toner base particle surface. The peripheral speed was also set to 100 m / sec in the spraying process and the film forming process. The mounting angle of the two-fluid nozzle was set so that the angle formed between the liquid spraying direction and the powder flow direction (hereinafter referred to as “spraying angle”) was parallel (0 °). With such an apparatus, 100 parts by weight of the prepared toner base particles and 10 parts by weight of resin fine particles were stirred and mixed for 5 minutes, and then ethanol was sprayed as a liquid at a spraying rate of 0.5 g / min, and the air flow rate was 5 L / min for 30 minutes. The resin fine particles were formed into a film on the surface of the toner base particles by spraying. Thereafter, the ethanol spraying was stopped and the mixture was stirred for 5 minutes to obtain the toner of Example 1. At this time, the discharge concentration of the liquid discharged through the through hole and the gas discharge portion was stable at about 1.4 Vol%. Moreover, the air flow rate which flows into the apparatus was adjusted to 5 L / min, and the total air flow from the two-fluid nozzle was flowed 10 L / min.
The shape factor SF2 of the toner after the coating process was 120.

(Example 2)
The toner of Example 2 was obtained in the same manner as in Example 1 except that the hot air temperature was changed from 190 ° C. to 170 ° C. in the pretreatment base particle surface treatment step S1b. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 133, and the shape factor SF2 of the toner after the coating step S3 was 128.

(Example 3)
A toner of Example 3 was obtained in the same manner as in Example 1 except that the hot air temperature was changed from 190 ° C. to 220 ° C. in the pretreatment base particle surface treatment step S1b. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 112, and the shape factor SF2 of the toner after the coating step S3 was 112.

Example 4
A toner of Example 4 was obtained in the same manner as in Example 1 except that the amount of the release agent in the mother particles before treatment was changed from 6.9 parts by weight to 5.5 parts by weight. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 122, and the shape factor SF2 of the toner after the coating step S3 was 120.

(Example 5)
A toner of Example 5 was obtained in the same manner as in Example 1 except that the melt kneading temperature was changed from 140 ° C. to 170 ° C. in the pre-treatment mother particle preparation step S1a. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 122, and the shape factor SF2 of the toner after the coating step S3 was 120.

(Comparative Example 1)
A toner of Comparative Example 1 was obtained in the same manner as in Example 1 except that the pre-treatment mother particle surface treatment step S1b was not performed. The shape factor SF2 of the toner base particles after the pretreatment base particle preparation step S1a was 143, and the shape factor SF2 of the toner after the coating step S3 was 130.

(Comparative Example 2)
A toner of Comparative Example 2 was obtained in the same manner as in Example 1 except that the hot air temperature was changed from 190 ° C. to 165 ° C. in the pre-treatment mother particle surface treatment step S1b. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 137, and the shape factor SF2 of the toner after the coating step S3 was 129.

(Comparative Example 3)
A toner of Comparative Example 3 was obtained in the same manner as in Example 1 except that the hot air temperature was changed from 190 ° C. to 230 ° C. in the pre-treatment mother particle surface treatment step S1b. The shape factor SF2 of the toner base particles after the pretreatment base particle surface treatment step S1b was 108, and the shape factor SF2 of the toner after the coating step S3 was 108.

(Comparative Example 4)
A toner of Comparative Example 4 was obtained in the same manner as in Example 1 except that the pre-treatment mother particle surface treatment step S1b and subsequent steps (steps S2 and S3) were not performed.
The physical properties of the toners of Examples 1 to 5 and Comparative Examples 1 to 4 are summarized in Table 1.

(Preparation of two-component developer)
A two-component developer was prepared by mixing 5 parts by weight of the toners of Examples and Comparative Examples with 95 parts by weight of a ferrite core carrier having a volume average particle diameter of 45 μm.
The obtained toners of Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated as follows.

[Storage stability]
Using the toners of Examples 1 to 5 and Comparative Examples 1 to 4, the storage stability was evaluated by the presence or absence of aggregates after high temperature storage. After 20 g of toner was sealed in a plastic container and allowed to stand at 60 ° C. for 72 hours, the toner was taken out and passed through a 230 mesh sieve. The weight of the toner remaining on the sieve was measured, and the residual amount, which is the ratio of this weight to the total toner weight, was determined and evaluated according to the following evaluation criteria. The lower the numerical value of the remaining amount, the more the toner is not blocked and the toner base particles are sufficiently covered with the coating layer.

The evaluation criteria are as follows.
A: Very good. No aggregation. The remaining amount is less than 1%.
○: Good. Aggregation trace amount. The remaining amount is 1% or more and less than 3%.
Δ: Yes. Small amount of aggregation. The remaining amount is 3% or more and less than 20%.
X: Defect. Large amount of aggregation. The remaining amount is 20% or more.

[Fixability]
A two-component developer containing the toners obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was filled in an apparatus obtained by modifying a commercial copying machine (trade name: MX-4500, manufactured by Sharp Corporation). Recording was performed by adjusting the amount of toner adhered to the recording paper in an unfixed state in a solid image portion of a sample image including a rectangular solid image portion of 20 mm in length and 50 mm in width to 0.5 mg / cm ^2. An unfixed image was formed on a recording paper (trade name: PPC paper SF-4AM3, manufactured by Sharp Corporation) as a medium. Next, a fixed image was created by fixing an unfixed image using an external fixing device manufactured using a fixing unit of a color multifunction peripheral. The operation of creating the fixed image was performed a plurality of times by increasing the temperature of the fixing roller from 130 ° C. in increments of 5 ° C., and the fixing non-offset region (° C.) was obtained. The fixing non-offset region (° C.) is a temperature region in which a low temperature offset and a high temperature offset do not occur, and is specifically represented by the following formula (6).
(Fixing non-offset range [° C]) = (High temperature offset generation temperature [° C])
-(Low temperature offset generation temperature [° C]) (2)

  In this embodiment, the occurrence of a high temperature offset and the occurrence of a low temperature offset are defined as the toner that has not been fixed on the recording paper at the time of fixing being attached to the recording paper after the fixing roller has made a full rotation while remaining attached to the fixing roller. To do. Note that the fixing process speed during the operation of creating a fixed image was set to 124 mm / second. The fixability was evaluated using the value of the non-fixing area of the fixing.

The evaluation criteria are as follows.
A: Very good. The fixing non-offset region is 50 ° C. or higher.
○: Good. The fixing non-offset region is 40 ° C. or higher and lower than 50 ° C.
Δ: Yes. The fixing non-offset region is 35 ° C. or higher and lower than 40 ° C.
X: Defect. The fixing non-offset region is less than 35 ° C.

[Cleanability]
A color composite machine (trade name: MX-4500, manufactured by Sharp Corporation) is filled with the two-component developer containing the toner obtained in Examples 1 to 5 and Comparative Examples 1 to 4, and a thickness of about 60 μm is used as a recording medium. Using a domestic medium quality paper (MI paper, Sharp Corporation recommended paper) with a surface roughness Ra of 1.0 μm, printing a chart with a printing rate of 5% continuously, after printing 30,000 sheets and after printing 50,000 sheets A test chart was formed. Three types of test charts were formed: a full-color image, a fine line chart, and white paper (printing rate 0%). The image defects, streaks, etc. of these three types of test charts were visually confirmed to evaluate the cleaning property.

The evaluation criteria are as follows.
A: Very good. There are no image defects, streaks, etc. on all three types of test charts after printing 50,000 sheets.
○: Good. There are no image defects, streaks, etc. on all three types of test charts after printing 30,000 sheets. After printing 50,000 sheets, some streaks appear only on one type of test chart.
Δ: Yes. After printing 30,000 sheets, some streaks occur only in one type of test chart.
X: Defect. Image defects, streaks, etc. occur in one or more types of test charts after printing 30,000 sheets.

〔Comprehensive evaluation〕
Based on the above evaluation results, the toners of Examples and Comparative Examples were comprehensively evaluated.

The overall evaluation criteria are as follows.
A: Very good. All evaluation results are ◎.
○: Good. There are one or more ○ evaluation results, and there are no Δ and × evaluation results.
Δ: Yes. There are one or more evaluation results of Δ, but there is no evaluation result of ×.
X: Defect. There are one or more evaluation results.

  These results are summarized in Table 2. In the storage stability of Table 2, “<1%” indicates “less than 1%”.

  As can be seen from Table 2, the storage stability, fixing properties and cleaning properties of the toners of the examples were good.

  However, in Example 4 in which the exposure amount of the release agent on the surface of the toner base particles is relatively small and Example 5 in which the dispersion diameter of the release agent exposed on the surface of the toner base particles is relatively small, the fixability is slightly lowered.

  The toners of Comparative Examples 1, 2, and 4 in which the shape factor of the toner base particles was too large deteriorated the storage stability. Further, Comparative Examples 1 and 4 in which the exposure amount of the release agent on the surface of the toner base particles was too small also deteriorated the fixability. In Comparative Example 3 in which the shape factor of the toner base particles was too small, the cleaning property deteriorated.

DESCRIPTION OF SYMBOLS 201 Toner manufacturing apparatus 202 Powder flow path 203 Spraying means 204 Rotating stirring means 206 Powder input part 207 Powder collection part 220 Stirring blade

Claims (7)

Pre-treatment mother particles containing a binder resin and a colorant are spheronized using a hot-air spheronizer, the shape factor SF2 is 110 or more and 135 or less, and the exposure amount of the release agent on the surface is toner mother particles Performing a pre-treatment mother particle surface treatment step to obtain toner mother particles of 2.3% by weight or more of the total amount,
Circulating means for recirculating toner mother particles and resin fine particles in a powder flow path including a rotating stirring chamber and a circulation pipe and returning them to the rotating stirring chamber by a rotating stirring means comprising a rotating disk having a rotating blade and a rotating shaft. And a rotary stirring device comprising a spraying means for spraying a plasticizing liquid capable of plasticizing the toner base particles and the resin fine particles with a carrier gas,
A resin fine particle attaching step for introducing toner fine particles and resin fine particles into the powder flow path in which the rotating stirring means is rotating, and attaching the resin fine particles to the toner mother particle surface;
A spraying step of spraying the plasticizing liquid from the spraying means onto the toner base particles and the resin fine particles in a fluid state;
And a film forming step in which the rotation of the rotary stirring means is continued until the resin fine particles adhering to the toner base particles are softened to form a film, and the toner base particles and the resin fine particles are fluidized.   The toner manufacturing method according to claim 1, wherein the toner base particles used in the resin fine particle adhesion step have a dispersion diameter of a surface release agent of 300 nm or more.   A toner produced by the toner production method according to claim 1.   A developer comprising the toner according to claim 3.   The developer according to claim 4, wherein the developer is a two-component developer composed of the toner and a carrier.   A developing device that develops a latent image formed on an image carrier using the developer according to claim 4 to form a toner image. An image carrier on which a latent image is formed;
A latent image forming means for forming a latent image on the surface of the image carrier;
An image forming apparatus comprising: the developing device according to claim 6.

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