JP2021140003A - Toner and two-component developer, and method for manufacturing toner - Google Patents

Abstract

To provide a toner that can prevent aggregation of toner and reduce the degree of fogging compared to before and a two-component developer, and a method for manufacturing a toner.SOLUTION: A toner has mixed therein a plurality of coloring particles containing a colorant and a binder resin and a plurality of non-coloring particles not containing a colorant. The coloring particles and the non-coloring particles are electrified to have the same polarity. The volume average particle diameter of the non-coloring particles is smaller than the volume average particle diameter of the coloring particles. A two-component developer includes toner and carrier. A method for manufacturing a toner includes: preparing transparent particles; preparing non-coloring particles from the prepared transparent particles; producing a coloring resin composition; preparing coloring particles from the produced coloring resin composition; and mixing the prepared non-coloring particles and the prepared coloring particles to produce mixed particles.SELECTED DRAWING: Figure 2

Description

The present invention relates to toner, in particular, a toner (toner for electrophotographic) used in an image forming apparatus such as a copying machine, a multifunction device, and a printer using an electrophotographic method, a two-component developer, and a method for producing the toner.

In an image forming apparatus using an electrophotographic method, an image is formed by undergoing, for example, each step of charging, exposure, development, transfer, cleaning, static elimination, and fixing. In the image forming apparatus, the surface of the photoconductor (electrostatic latent image carrier) that is rotationally driven in the charging step is uniformly charged by the charging device, and the surface of the charged photoconductor is uniformly charged by the exposure device in the exposure step. Is irradiated, and an electrostatic latent image is formed on the surface of the photoconductor. Next, in the developing step, an electrostatic latent image on the surface of the photoconductor is developed by a developing device using a developer to form a toner image on the surface of the photoconductor. That is, a developed region and a non-developed region are formed in the electrostatic latent image on the surface of the photoconductor, and the toner adheres to the developed region side due to the development bias applied in the developing apparatus, so that the toner image is formed on the photoconductor surface. It is formed. Next, in the transfer step, the toner image on the surface of the photoconductor is transferred onto the transfer material by the transfer device, and then in the fixing step, the toner image is fixed on the transfer material by being heated by the fixing device.

In the electrophotographic method, as a developer for developing an electrostatic latent image formed on the surface of a photoconductor, there are a two-component developer of toner and a carrier and a one-component developer of only toner containing no carrier. In any case, the toner is transferred not only to the developed area but also to the non-developed area in a small amount in the developing process. Then, image defects in which toner adheres to the non-image region on the image corresponding to the non-developed region on the surface of the photoconductor, so-called background fog (hereinafter, simply referred to as fog) occurs.

Conventionally, the reduction of fog has been dealt with by reducing the presence of small particle toner that is difficult to control by electrostatic force, but the reality is that it is not sufficient. In particular, it is difficult to deal with uneven charging that tends to occur when a charging roller is used as the charging device.

Regarding this point, Patent Document 1 contains, as a toner, colored resin particles and transparent resin particles charged in the opposite polarity to the colored resin particles in a predetermined mass ratio, and averages the colored resin particles and the transparent resin particles. By using toner with a particle size ratio of 0.8 to 1.2 and reducing the amount of migration of colored resin particles to the non-developed region by the amount that the transparent resin particles migrate to the non-developed region, the degree of fog Is disclosed to suppress.

Japanese Unexamined Patent Publication No. 2008-83254

However, in the toner described in Patent Document 1, since the transparent resin particles have the opposite polarity to the colored resin particles, the transparent resin particles and the colored resin particles tend to adhere to each other due to charging, so that the toner tends to aggregate. Further, the reverse-polarity particles selectively shift to the non-developed region, but in a normal document, the non-developed region is wider than the developed region, so that the reverse-polarity particles are consumed in large quantities. Furthermore, since the average particle size of the transparent resin particles and the average particle size of the colored resin particles are about the same, the number of the transparent resin particles is not large, so that the particles are quickly consumed from the developing agent and lose their effect. It should be noted that the same polar particles also shift to the non-developed region, but this phenomenon is more likely to occur in the small particle size particles that are difficult to control by the electric field.

Therefore, an object of the present invention is to provide a toner, a two-component developer, and a method for producing the toner, which can suppress the aggregation of toner and suppress the degree of fog more than before.

In order to solve the above problems, the present invention provides the following toner, a two-component developer, and a method for producing the toner.

(1) Toner The toner according to the present invention is a toner in which a plurality of colored particles containing a colorant and a binder resin and a plurality of non-colored particles not containing a colorant are mixed with the colored particles. It is characterized in that it is charged with the same polarity as the non-colored particles, and the volume average particle size of the non-colored particles is smaller than the volume average particle size of the colored particles.

(2) Two-component developer The two-component developer according to the present invention is characterized by containing the toner according to the present invention and a carrier.

(3) Method for producing toner The method for producing toner according to the present invention is a method for producing toner for producing the toner according to the present invention, which is a transparent particle preparation step for preparing transparent particles and a transparent particle preparation step. A non-colored particle preparation step for preparing non-colored particles from the transparent particles prepared in the above, a colored resin composition manufacturing step for preparing a colored resin composition, and a colored resin composition prepared in the colored resin composition manufacturing step. Mixed particles are prepared by mixing the colored particle preparation step of preparing colored particles from the above, the non-colored particles prepared in the non-colored particle preparation step, and the colored particles prepared in the colored particle preparation step. It is characterized by including a step of producing mixed particles.

According to the present invention, it is possible to suppress the aggregation of toner and to suppress the degree of fog as compared with the conventional case.

It is a conceptual diagram which shows the structure of the toner which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the image formation process by toner which concerns on this Embodiment. It is a process drawing which shows the manufacturing method of the toner which concerns on this Embodiment.

FIG. 1 is a conceptual diagram showing a configuration of a toner T according to an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining an image forming process using the toner T according to the present embodiment. FIG. 3 is a process diagram showing a method for producing the toner T according to the present embodiment.

[toner]
As shown in FIG. 1, the toner T according to the present embodiment includes a plurality of colored particles Ta to Ta containing a colorant and a binder resin, and a plurality of non-colored particles Tb to Tb (high) containing no colorant. Bright particles) and a plurality of external additives Tc to Tc.

The toner T is a mixture of colored particles Ta to Ta, non-colored particles Tb to Tb, and external additives Tc to Tc. Then, the colored particles Ta to Ta and the non-colored particles Tb to Tb are charged to the same polarity (positive electrode or negative electrode), and the volume average particle diameter of the non-colored particles Tb to Tb is larger than the volume average particle diameter of the colored particles Ta to Ta. small. Here, the non-colored particles Tb to Tb do not develop color on the transfer material S after fixing.

Further, the external additives Tc to Tc are attached to the surfaces Ta1 to Ta1 of the colored particles Ta to Ta and the surfaces Tb1 to Tb1 of the non-colored particles Tb to Tb.

1. 1. Image formation process using toner Next, the image formation process using toner T will be described in detail below with reference to FIG.

FIG. 2 shows a state before the development process, a state of the development process, and a state of the transfer process.

As shown in FIG. 2, before the developing process, the non-colored particles Tb to Tb have the colored particles Ta to Ta on the surface of the photoconductor 10 (electrostatic latent image carrier such as a photoconductor drum) prior to the developing process. The colored particles Ta to Ta are charged to the same polarity (minus in this example) as the charging polarity (minus in this example) so that they do not easily adhere to the undeveloped region β2 of 10a. Then, when the electrostatic latent image β is formed in the uniformly charged charged region α on the surface 10a of the photoconductor 10 (when the charge in the charged region is partially removed), the developed region β1 and the non-developed region β1 are formed. β2 and are formed.

In the developing process, the electrostatic latent image β formed on the surface 10a of the photoconductor 10 is developed by the toner T to form the toner image Ti.

By the way, in the conventional developing process, on the surface 10a of the photoconductor 10, the toner T is not transferred to the undeveloped region β2 (not developed), and the toner T is desired to be transferred only to the developed region β1 (developed). However, since the development is uniformly performed, the toner T inevitably migrates to the non-developed region β2 in a small amount, and eventually fog occurs in the non-image region γ2 other than the image region γ1 on the transfer material S. Resulting in. For example, among the particles of the toner T, particles having a small particle size that cannot be controlled by electrostatic force tend to remain in the undeveloped region β2.

In this respect, in the present embodiment, in the developing process, the colored particles Ta to Ta and the non-colored particles Tb to Tb are transferred to the developed region β1 formed on the surface 10a of the photoconductor 10, while the non-developed region β2. The non-colored particles Tb to Tb migrate and the colored particles Ta to Ta do not or hardly migrate. That is, by making the volume average particle diameter of the non-colored particles Tb to Tb smaller than the volume average particle diameter of the colored particles Ta to Ta, the non-colored particles Tb to Tb can be positively transferred to the undeveloped region β2. As a result, the amount of migration of the colored particles Ta to Ta to the undeveloped region β2 can be made smaller than the amount of migration of the uncolored particles Tb to Tb to the undeveloped region β2 as compared with the conventional case. Therefore, it is possible to effectively prevent the movement of the colored particles Ta to Ta, whose volume average particle size is larger than the volume average particle size of the non-colored particles Tb to Tb, to the undeveloped region β2.

In the transfer process, the toner image Ti formed on the surface 10a of the photoconductor 10 is transferred (transferred) onto the transfer material S such as transfer paper by the transfer potential.

Next, although not shown, in the fixing process, the toner T transferred onto the transfer material S is fixed to the transfer material S and spread, and the image is fixed to the transfer material S. At this time, since the non-colored particles Tb to Tb in the non-developed region β2 do not develop color on the transfer material S after fixing, they do not contribute to color development after fixing and in the non-image region γ2 on the transfer material S. Fog is inconspicuous or inconspicuous.

According to the present embodiment, the colored particles Ta to Ta and the non-colored particles Tb to Tb are charged to the same polarity (positive electrode or negative electrode), so that the non-colored particles Tb to Tb and the colored particles Ta to Ta adhere to each other. This can be made difficult, and thus the aggregation of the toner T can be suppressed. Moreover, the colored particles Ta to Ta and the non-colored particles Tb to Tb are charged with the same polarity, and the volume average particle size of the non-colored particles Tb to Tb is smaller than the volume average particle size of the colored particles Ta to Ta. The amount of migration of Ta to Ta to the undeveloped region β2 can be made smaller than the amount of migration of the uncolored particles Tb to Tb to the undeveloped region β2, and therefore, the amount of migration of the uncolored particles Tb to Tb can be made smaller than before. The amount of transition of the colored particles Ta to Ta to the non-developed region β2 can be reduced as much as the amount of the transition to the undeveloped region β2. As a result, the degree of fog can be suppressed as compared with the conventional case.

2. Toner Manufacturing Method Next, the toner T manufacturing method will be described in detail below with reference to FIG.

The method for producing the toner T according to the present embodiment includes a transparent particle preparation step P1, a non-colored particle preparation step P2, a colored resin composition preparation step P3, a colored particle preparation step P4, and a mixed particle preparation step P5. , The external addition step P6 is included.

[1] Transparent particle preparation step P1
In the transparent particle preparation step P1, transparent particles are prepared. Specifically, in the transparent particle preparation step P1, transparent particles (transparent resin fine particles) are prepared. The transparent particles are used as materials constituting the non-colored particles Tb to Tb in the subsequent mixed particle preparation step P5. Transparent particles can also be used as a coating material on the surface of colored particles. By doing so, for example, it is possible to prevent the occurrence of aggregation due to melting of low melting point components such as a mold release agent contained in the colored particles during storage.

The transparent particles can be obtained, for example, by emulsifying and dispersing a resin, which is a raw material of the transparent particles, with a homogenizer or the like to make the particles finer. It can also be obtained by polymerizing the monomer component of the resin which is the raw material of the transparent particles.

As the resin used as the raw material of the transparent particles, for example, the resin used as the material of the toner T can be used, and examples thereof include polyester, acrylic resin, styrene resin, and styrene-acrylic copolymer. Among the resins exemplified above, the transparent particles preferably contain an acrylic resin and a styrene-acrylic copolymer. Acrylic resins and styrene-acrylic copolymers have many advantages such as being lightweight, having high strength, high transparency, being inexpensive, and being easy to obtain materials having a uniform particle size.

The resin used as a raw material for the transparent particles may be the same type of resin as the binder resin contained in the colored particles Ta to Ta, or may be a different type of resin, but the surface modification of the toner T may be used. It is preferable that a different type of resin is used in this respect. When a different type of resin is used as the raw material for the transparent particles, the softening temperature of the resin used as the raw material for the transparent particles is higher than the softening temperature of the binder resin contained in the colored particles Ta to Ta. Is preferable. As a result, the toner produced by the production method according to the present embodiment can effectively prevent the toners from fusing to each other during storage, and the storage stability can be improved. The softening temperature of the resin used as a raw material for the transparent particles is preferably 80 ° C. or higher and 140 ° C. or lower, although it depends on the image forming apparatus in which the toner T is used. By using a resin in such a temperature range, it is possible to obtain a toner having both storage stability and fixability.

[2] Non-colored particle preparation step P2
In the non-colored particle preparation step P2, non-colored particles Tb to Tb are prepared from the transparent particles prepared in the transparent particle preparation step P1. Specifically, in the non-colored particle preparation step P2, the lattice of the transparent particles prepared by emulsion polymerization with respect to the resin which is the raw material of the transparent particles is freeze-dried, and the non-colored particles Tb to contain no colorant (not colored). Obtain Tb. By classifying the obtained non-colored particles Tb to Tb, non-colored particles Tb to Tb having a predetermined volume average particle size or less are obtained. Any method may be used as the drying method. For example, dried transparent particles can be obtained by using a method such as hot air heat transfer type drying, conduction heat transfer type drying, far infrared ray drying, or microwave drying.

[3] Colored Resin Composition Fabrication Step P3
In the colored resin composition production step P3, a colored resin composition is produced. Specifically, in the colored resin composition manufacturing step P3, the binder resin and the colorant which are the raw materials (colored resin composition) of the colored particles Ta to Ta, and the additives such as the release agent and the charge control agent are mixed (raw materials). Mixing process).

(A) Bending resin The binding resin is not particularly limited, and a known binding resin for black toner or color toner can be used. For example, styrene resins such as polystyrene and styrene-acrylic acid ester copolymer resins, acrylic resins such as polymethylmethacrylate, polyolefin resins such as polyethylene, polyesters, polyurethanes and epoxy resins can be mentioned. Further, a resin obtained by mixing a mold release agent with a raw material monomer mixture and performing a polymerization reaction may be used. As the binder resin, one type can be used alone, or two or more types can be used in combination.

Polyester is suitable as a binder resin for color toners because it has excellent transparency and can impart good powder fluidity, low-temperature fixability, secondary color reproducibility, etc. to aggregated particles. As the polyester, a known polyester can be used, and examples thereof include a polycondensate of a polybasic acid and a polyhydric alcohol. As the polybasic acid, those known as monomers for polyester can be used, and aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid can be used. , Alius carboxylic acids such as maleic anhydride, fumaric acid, amber acid, alkenyl anhydride amber acid, adipic acid, methyl esterified products of these polybasic acids and the like. One type of polybasic acid can be used alone, or two or more types can be used in combination. As the polyhydric alcohol, those known as monomers for polyester can be used, for example, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol and glycerin, and cyclohexanediol. , Cyclohexanedimethanol, alicyclic polyhydric alcohols such as hydrogenated bisphenol A, ethylene oxide adducts of bisphenol A, aromatic diols such as propylene oxide adducts of bisphenol A and the like. One type of polyhydric alcohol can be used alone, or two or more types can be used in combination. 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 brought into contact with each other in the presence or absence of an organic solvent and in the presence of a polycondensation catalyst. This is performed, and the process ends when the acid value, softening point, etc. of the produced polyester reach a predetermined value. This gives polyester. When a methyl esterified product of a polybasic acid is used as a part of the polybasic acid, a demethanolation polycondensation reaction is carried out. In this polycondensation reaction, for example, the carboxyl group content at the end of the polyester can be adjusted by appropriately changing the compounding ratio of the polybasic acid and the polyhydric alcohol, the reaction rate, etc., and thus the characteristics of the obtained polyester are modified. 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-dispersing polyester in water can also be used by binding a hydrophilic group such as a carboxyl group or a sulfonic acid group to the main chain and / or the side chain of the polyester. Further, polyester and acrylic resin may be grafted and used.

The binder resin preferably has a glass transition point of 50 ° C. or higher and 80 ° C. or lower. If the glass transition point of the binder resin is less than 50 ° C., blocking in which the toner T thermally aggregates inside the image forming apparatus is likely to occur, and the storage stability may be lowered. If the glass transition point of the binder resin exceeds 80 ° C., the fixability of the toner T to the recording medium is lowered, and there is a possibility that fixing failure may occur.

(B) Colorant As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the field of electrophotographic can be used.

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

Examples of the yellow colorant include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, nable yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Kinolin Yellow Lake, Permanent Yellow NCG, Tartrajin 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 93, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 138 and the like.

Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indus lem brilliant orange RK, benzidine orange G, indus lem brilliant orange GK, and C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43 and the like.

Examples of red colorants include red iron oxide, cadmium red, lead tan, mercury sulfide, cadmium, permanent red 4R, resole 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 Carmin 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. Pigment Red 222 and the like.

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

Examples of the blue colorant include dark blue, cobalt blue, alkaline blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, 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. Pigment Blue 60 and the like can be mentioned.

Examples of the green colorant include chrome green, chromium oxide, pigment green B, mica light green lake, final yellow green G, and C.I. I. Pigment Green 7 and the like.

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

The colorant may be used in a masterbatch in order to uniformly disperse the synthetic resin additive in the kneaded product. Further, two or more kinds of additives for synthetic resin may be used as composite particles. Composite particles are produced, for example, by adding an appropriate amount of water, lower alcohol, etc. to two or more kinds of additives for synthetic resins, granulating them with a general granulator such as a high speed mill, and drying them. Can be done.

(C) Charge control agent As the charge control agent, control agents for positive charge control and negative charge control, which are commonly used in the electrophotographic field, can be used. Examples of the charge control agent for positive charge control include niglosin dye, basic dye, quaternary ammonium salt, quaternary phosphonium salt, aminopyrine, pyrimidine compound, polynuclear polyamino compound, aminosilane, niglosin dye and its derivative, and triphenylmethane. Derivatives, guanidine salts, amidine salts and the like can be mentioned. Examples of the charge control agent for negative charge control include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, naphthenic acid metal salts, metal complexes and metal salts of salicylic acid and its derivatives ( Metals include chromium, zinc, zirconium, etc.), boron compounds, fatty acid soaps, long-chain alkylcarboxylates, resin acid soaps, and the like. One type of charge control agent can be used alone, or two or more types can be used in combination as required. 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 to 3 parts by weight with respect to 100 parts by weight of the binder resin.

When the transparent particles are used as a coating material on the surface of the colored particles, the charge control agent may contain all or a part of the transparent particles in the coating layer of the transparent particles. Further, the polarity of the transparent particles can be controlled depending on the specific charge control agent, and it can be used to match the polarity with the colored particles.

(D) Mold release agent As the mold release agent, those commonly used in the field of electrophotographic photography can be used, for example, paraffin wax and its derivatives, petroleum waxes such as microcrystallin wax and its derivatives, Fishertropsh wax and Hydrocarbon-based synthetic waxes such as derivatives, polyolefin waxes (polyethylene wax, polypropylene wax, etc.) and derivatives thereof, low-molecular-weight polypropyrin waxes and derivatives thereof, polyolefin-based polymer waxes (low-molecular-weight polyethylene waxes, etc.) and derivatives thereof, carnauba Wax and its derivatives, rice wax and its derivatives, candelilla wax and its derivatives, vegetable waxes such as wood wax, animal waxes such as beeswax and whale wax, fats and oils synthetic waxes such as fatty acid amides and phenolic fatty acid esters, long chains Examples thereof include carboxylic acids and derivatives thereof, long-chain alcohols and derivatives thereof, silicone-based polymers, and higher fatty acids. Derivatives include oxides, block copolymers of vinyl-based monomers and wax, and graft-modified products of vinyl-based monomers and wax. The amount of wax used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 parts by weight to 20 parts by weight, more preferably 0.5 parts by weight to 10 parts by weight with respect to 100 parts by weight of the binder resin. Particularly preferably, it is 1.0 part by weight to 8.0 part by weight.

In the colored resin composition manufacturing step P3, the raw materials of the colored particles Ta to Ta containing the binder resin, the colorant and other additives are dry-mixed with a mixer. Known mixers can be used, for example, Henchel Mixer (trade name, manufactured by Mitsui Mine Co., Ltd.), Super Mixer (trade name, manufactured by Kawata Co., Ltd.), Mechanomill (trade name, manufactured by Okada Seiko Co., Ltd.). Henshell type mixing device such as (manufactured by), Ongmill (trade name, manufactured by Hosokawa Micron Co., Ltd.), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), etc. Can be mentioned. When the raw materials of the colored particles Ta to Ta are mixed in the colored resin composition manufacturing step P3, the process proceeds to the colored particle preparation step P4.

[4] Colored particle preparation step P4
In the colored particle preparation step P4, colored particles Ta to Ta are prepared from the colored resin composition prepared in the colored resin composition manufacturing step P3. Specifically, the colored particle preparation step P4 includes a melt-kneading step P41, a pulverization step P42, and a classification step P43.

[4-1] Melting and kneading step P41
In the melt-kneading step P41, a mixture obtained by mixing the raw materials of the colored particles Ta to Ta obtained in the colored resin composition manufacturing step P3 is melt-kneaded, and the colorant and other additives are dispersed in the binder resin.

A known kneader can also be used, and for example, a general kneader such as a twin-screw extruder, a triple roll, or a lab blast mill can be used. More specifically, for example, 1-axis or 2-axis such as TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87, PCM-30 (trade name, all manufactured by Ikekai Co., Ltd.). Examples of open-roll type kneaders such as Extruder and Kneedex (trade name, manufactured by Mitsui Mining Co., Ltd.) can be mentioned. Among these, an open roll type kneader is preferable. When melt-kneading is performed in the melt-kneading step P41 and components such as a colorant are sufficiently dispersed in the binder resin to obtain a melt-kneaded product, the process proceeds to the crushing step P42.

[4-2] Crushing step P42
In the pulverization step P42, the melt-kneaded product obtained in the melt-kneading step P41 is cooled, solidified, and pulverized. As a crusher used for crushing, a known crusher can be used, for example, a jet crusher that crushes using a supersonic jet flow, a rotor (rotor) and a stator (liner) that rotate at high speed. An impact type crusher or the like that introduces a coarse crushed material into the space formed between the two and crushes the coarse crushed material can be used. When the melt-kneaded product is crushed in the crushing step, the process proceeds to the classification step.

[4-3] Classification step P43
In the classification step P43, the fine particles in the pulverized product obtained in the pulverization step P42 are removed to obtain colored particles Ta to Ta. For the classification, a known classifier that removes fine powder by classification by centrifugal force or by wind power can be used.

The colored particles Ta to Ta obtained through the melt-kneading step P41, the crushing step P42, and the classification step P43 as described above 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 colored particles Ta to Ta is 4 μm or more and 8 μm or less, a high-definition image can be stably formed for 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 effect of reducing the consumption of toner T is also produced. If the volume average particle size of the colored particles Ta to Ta is less than 4 μm, the particle size of the colored particles Ta to Ta may become too small, resulting in high charging and low fluidity. When the high charge and the low fluidity occur, the toner T cannot be stably supplied to the photoconductor 10, and there is a possibility that fog and a decrease in image density may occur. When the volume average particle size of the colored particles Ta to Ta exceeds 8 μm, the particle size of the colored particles Ta to Ta becomes large, the layer thickness of the formed image becomes high, and the image becomes remarkably grainy, and a high-definition image is obtained. It is not desirable because it cannot be done. Further, as the particle size of the colored particles Ta to Ta increases, the specific surface area decreases and the amount of charge of the toner T decreases. When the amount of charge of the toner T becomes small, the toner T is not stably supplied to the photoconductor 10, and there is a possibility that in-machine contamination due to toner scattering may occur.

[5] Mixed particle preparation step P5
[5-1] Mixing step P51
The mixed particle preparation step P5 includes a mixing step P51. In the mixing step P51, the non-colored particles Tb to Tb prepared in the non-colored particle preparation step P2 and the colored particles Ta to Ta prepared in the colored particle preparation step P4 are mixed using a conventionally known mixer. Mixed particles (Ta to Ta) and (Tb to Tb) are prepared.

[5-2] Encapsulation step P52
The mixed particle preparation step P5 may further include an encapsulation step P52 (membrane treatment step). In the encapsulation step P52, the colored particles Ta to Ta and the non-colored particles are used to cover all or part of the surfaces Ta1 to Ta1 of the colored particles Ta to Ta1 with a part of the non-colored particles Tb to Tb by a flow device. A mixing treatment of mixing Tb to Tb is performed to swell and soften the colored particles Ta to Ta and the non-colored particles Tb to Tb, and a part of the non-colored particles causes the entire surface Ta1 to Ta1 of the colored particles Ta to Ta and the surface Ta1 to Ta1 of the colored particles Ta to Ta1. A coating layer is formed on a part.

A typical configuration of the flow device is a powder flow path for flowing the colored particles Ta to Ta and the non-colored particles Tb to Tb, and the non-colored particles Tb to Tb adhered to the surfaces Ta1 to Ta1 of the colored particles Ta to Ta1. It includes a rotary stirring means for applying an impact force in a state, a temperature adjusting jacket for adjusting the temperature in the flow device, a powder charging section, and a powder collecting section.

In the manufacturing method according to the present embodiment, first, while rotating the rotary stirring means, the temperatures in the powder flow path and the rotary stirring means are brought to a predetermined temperature through a medium through a temperature adjusting jacket arranged outside the rotary stirring means. adjust. Thereby, the temperature range in which the colored particles Ta to Ta in the powder flow path do not aggregate can be controlled, and the colored particles can be coated with the fine transparent fine particles by the impact force.

Next, the colored particles Ta to Ta and the non-colored particles Tb to Tb are supplied to the powder flow path from the powder charging portion in a state where the rotating shaft member of the rotary stirring means is rotated. The colored particles Ta to Ta and the non-colored particles Tb to Tb supplied to the powder flow path are agitated by the rotary stirring means and flow in a certain direction in the powder flow path. By flowing for a predetermined time, the non-colored particles Tb to Tb adhere to the surfaces Ta1 to Ta1 of the colored particles Ta to Ta.

Here, if the flow time is short, the colored particles Ta to Ta and the non-colored particles Tb to Tb are not coated, so that it is not possible to form a coating layer having a desired coating ratio in the finally obtained toner. .. Further, when the flow time is long, the non-colored particles Tb to Tb are heated during the flow, and the non-colored particles Tb to Tb are aggregated with each other, or the non-colored particles Tb to Tb are attached to the surfaces Ta1 to Ta1. Aggregation of Ta to Ta occurs.

Conventionally, as the flow time, the relationship between the coating state of the colored particles Ta to Ta and the non-colored particles Tb to Tb and the flow time is experimentally acquired in advance, and based on the acquired relationship. The flow time to obtain the desired coating state is determined. When the flow is started, the mixing process is terminated by flowing for the determined flow time. During the mixing process, the coating state is not confirmed, or even if it is confirmed, it is only confirmed when the determined time has elapsed.

[6] External attachment process P6
In the external addition step P6, the external additives Tc to Tc are externally added to the mixed particles (Ta to Ta) and (Tb to Tb) mixed in the mixed particle preparation step P5.

The external additives Tc to Tc may be further added to the toner T in which the colored particles Ta to Ta and the non-colored particles Tb to Tb are mixed. Examples of the external additives Tc to Tc include inorganic fine powders such as silicon dioxide, titanium oxide, aluminum oxide, cerium oxide, zinc oxide, tin oxide, and zirconium oxide, polystyrene, acrylic resin, styrene-acrylic resin, and polyester. Examples thereof include resin fine powders such as polyolefin, cellulose, polyurethane, benzoguanamine, melamine resin, nylon, silicone resin, phenol resin, and vinylidene fluoride. The inorganic fine powder may be surface-treated with a hydrophobizing agent such as silicone oil, a silane coupling agent, or hexamethyldisilazane (HMDS). By using such external additives Tc to Tc, it is possible to obtain effects such as improvement of fluidity, improvement of triboelectricity, heat resistance, improvement of long-term storage property, improvement of cleaning characteristics, and control of surface wear characteristics of the photoconductor 10. can.

As the particle size of the external additives Tc to Tc, it is preferable that the number average particle size of the primary particles is 5 nm or more and less than 40 nm. By using the external additives Tc to Tc having such a particle size, it is possible to prevent the external additives Tc to Tc from being detached from the toner T. Further, the external additives Tc to Tc are preferably added in an amount of 0.1 part by weight or more and 5 parts by weight or less with respect to 100 parts by weight of the toner. The external additives Tc to Tc are added to the toner T using a conventionally known mixer.

Thus, the toner T composed of the colored particles Ta to Ta, the non-colored particles Tb to Tb, and the external additives Tc to Tc can be obtained.

[Two-component developer]
The two-component developer according to the present embodiment includes the toner T according to the present embodiment and a carrier (not shown). The two-component developer can be produced by mixing the toner T and the carrier using a known mixer. The weight ratio of the toner T to the carrier is not particularly limited, and examples thereof include 3:97 to 12:88.

[Career]
The carrier is agitated and mixed with the toner T in the developing tank to give the toner T a desired charge. Further, the carrier acts as an electrode between the developing device and the photoconductor 10, carries the charged toner T to the electrostatic latent image on the photoconductor 10, and plays a role of forming the toner image. The carrier is held on the developing roller of the developing apparatus by magnetic force, acts on the developing, then returns to the developing tank again, is stirred and mixed again with the new toner T, and is used repeatedly until the end of its life.

The carrier has a carrier core material and a resin layer that covers the carrier core material. The carrier core material is not particularly limited as long as it is used in the electrophotographic field. Specific examples of the material of the carrier core material include magnetic metals such as iron, copper, nickel and cobalt, and magnetic metal oxides such as ferrite and magnetite. The volume average particle diameter of the carrier core material is not particularly limited, and examples thereof include 30 μm to 100 μm. The resin layer preferably contains a silicone resin or an acrylic resin. Silicone resins can delay the progress of contamination of the carrier coat layer and are suitable for long-life use. The resin layer may contain a fluororesin. In particular, it can be suitably used when used for positively charged toner. Specific examples of the fluororesin include polytetrafluoroethylene (PTFE), perfluoroalkoxy resin (PFA), and ethylene / ethylene tetrafluoroethylene copolymer (ETFE).

Next, examples will be specifically described together with comparative examples, but the present invention is not particularly limited thereto. In the following Examples and Comparative Examples, the volume average particle diameter of the non-colored fine particles, the volume average particle diameter of the colored particles and the non-colored particles, the fine particle ratio of the colored particles, and the fine powder ratio in the toner were measured as follows.

[Volume average particle size of non-colored fine particles (number average particle size of primary particles)]
The measurement was performed using a laser diffraction / scattering method particle size distribution measuring device (trade name: Microtrack MT3000, manufactured by Nikkiso Co., Ltd.). In order to prevent the agglomeration of the measurement sample, a dispersion in which the measurement sample was dispersed in an aqueous solution of Family Fresh (manufactured by Kao Corporation) was added and stirred, then injected into the device and measured twice to obtain the average. .. The measurement conditions were measurement time: 30 seconds, particle refractive index: 1.4, particle shape: non-spherical, solvent: water, solvent refractive index: 1.33. The volume particle size distribution of the sample for measurement is measured, and the particle size at which the cumulative volume from the small particle size side in the cumulative volume distribution is 50% is calculated as the volume average particle size (μm) of the particles (non-colored particles). bottom.

[Volume average particle size of colored particles and non-colored particles]
The measurement was performed by a flow type particle image analyzer (FPIA) described later.

[Colored particle fine powder ratio and fine powder ratio in toner]
The measurement was performed by a flow type particle image analyzer (FPIA) described later.

[1] Transparent particle preparation step P1
Table 1 is a chart showing the properties, particle size, and charge polarity of the transparent particles prepared in the transparent particle preparation step P1. The particle size in Table 1 has the same meaning as “particle size D50” in Table 2 described later, and indicates the volume average particle size (median particle size). The volume average particle size (median particle size) is the same for the FPIA particle size Dv50 in Table 2 and Table 3 described later, and the high-luminance particle size Dv50 in the toner in Table 6 described later.

In the transparent particle preparation step P1, a fine particle dispersion (solid content of about 10% by weight) of a non-colored styrene-butyl acrylate copolymer (StAc copolymer resin) was prepared by an emulsion polymerization method. A water-affinitive initial condensate of melamine and / or benzoguanamine and formaldehyde is condensed and cured in an aqueous liquid containing a surfactant in the presence of an alkylbenzene sulfonic acid having an alkyl group having 12 carbon atoms to cure non-colored. A fine particle dispersion of resin (solid content of about 10%) was prepared. Further, by reducing the amount of alkylbenzene sulfonic acid, fine particle dispersions (solid content of about 10%) having different particle sizes were prepared.

[2] Non-colored particle preparation step P2
Table 2 shows the particle size and charging polarity of the non-colored particles prepared in the non-colored particle preparation step P2. If the middle of the histogram is not corrected and calculated, the particles are accumulated from the small particles. The maximum particle size is 50% lower than the cumulative distribution, and it is also called the median particle size in volume units.

In the non-colored particle preparation step P2, a fine particle dispersion (solid content of about 10% by weight) of a StAc copolymer (transparent particle TF1), which is a transparent fine particle produced by emulsion polymerization, is freeze-dried, and an elbow jet classifier EJ- The particles were classified using LABO (manufactured by Nittetsu Mining Co., Ltd.), and the recovered fine powder side was classified again to obtain uncolored non-colored particles WF1 to WF5 (non-colored particles). Further, in the same manner, the melamine-based non-colored fine particles were freeze-dried and then classified to obtain non-colored particles WF6 and WF7 (non-colored particles). Here, the "non-colored fine particles" are particles in the fine particle dispersion liquid at the time of preparing the toner, and the "non-colored particles" are aggregates prepared by drying the non-colored fine particles and are particles used for mixing. ..

Further, for the non-colored particles WF1 to WF7, the volume average particle size (median particle size) was determined by an imaging type measuring device including the melamine-based non-colored particles WF6 and WF7. The volume average particle size of the powder particles can be measured using, for example, a flow type particle image analyzer (FPIA), but is not particularly limited as long as the measurement principle is the same. Here, the non-colored particles WF1 to WF7 were measured using a flow-type particle image analyzer "FPIA-3000" (manufactured by Malvern).

[3] Colored Resin Composition Fabrication Step P3
A polyester (binding resin), a colorant, a mold release agent, and a charge control agent were mixed by kneading to prepare a colored resin composition. The toner matrix particle raw material and the amount of the toner added were as follows.

Polyester resin (trade name: Diacron, manufactured by Mitsubishi Rayon Co., Ltd., glass transition temperature 52 ° C, softening temperature 112 ° C) 89.0% (parts)
・ C. I. Pigment Blue 15: 3 6.0% (parts)
-Release agent (carnauba wax, melting point 82 ° C) 4.0% (parts)
・ Charge control agent (trade name: Bontron E84, Orient Chemical Industry Co., Ltd.)
1.0% (parts)
[4] Colored particle preparation step P4
Table 3 is a chart showing the particle size and charging polarity of the colored particles prepared in the colored particle preparation step P4. In Table 3 and Table 4 described later, "colored particle fine powder ratio Fc" is a ratio of particle size of 2 μm or less (pop ↓ 2 μm) to the frequency distribution based on the number of colored particles.

In the colored particle preparation step P4, each of the above components is premixed with a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.) and then a twin-screw extrusion kneader (trade name: PCM65, manufactured by Ikegai Corp.). ) Was melt-kneaded. This melt-kneaded product was roughly pulverized with a cutting mill (trade name: VM-16, manufactured by Orient Co., Ltd.).

It was finely pulverized with a jet mill (manufactured by Hosokawa Micron Co., Ltd.) to obtain a force-bearing particle CP.

Further, colored particles CP1 to CP3 were produced by classifying with a wind power classifier (manufactured by Hosokawa Micron Co., Ltd.).

[5] Mixed particle preparation step P5
Tables 4 to 7 are charts showing various measured values in various mixing treatments of powder mixing, film formation treatment, and classification treatment of the mixed particles (toner) mixed in the mixed particle preparation step P5 together with the evaluation results of the images. Is.

1 kg of colored particles are charged into a Henschel mixer (trade name: FM20C, manufactured by Mitsui Mining Co., Ltd.), and after adding non-colored particles according to the conditions, the rotating shaft member is stirred and mixed for 0.5 minutes at a peripheral speed of 10 m / sec. After that, the discharged material was repeatedly collected. Various measured values were obtained for the mixed particles.

In Table 6, the “high-luminance particle ratio Wt in toner (average brightness ↑ 90)” can be obtained as follows (Journal of the Imaging Society of Japan, Vol. 46, No. 6: 465-471 (2007)). Particle shape measurement technology ").

That is, in the measuring device, an image obtained by an image sensor such as a CCD is sampled into an appropriate pixel size according to the resolution, the density is quantized in 256 gradations for each pixel, and then converted to grayscale brightness. .. At this time, in the case of a color image, each color is converted so that the brightness is uniform by an appropriate method. It is assumed that the brightness shown here is darker when it is low and brighter when it is high, and the particles are imaged by a method that makes the background brighter.

A particle image is extracted from the entire image captured using this grayscale image. At this time, the particles can be easily recognized by various image processing (smoothing, sharpening) and the like.

After that, binarization is performed to separate the particle image and the background image. At this time, it is necessary to adjust the above-mentioned parameters and the level of image processing so that the grayscale brightness can be binarized with a threshold value of an appropriate brightness level (about 150 to 180). In particular, even fine particles and highly transparent transparent particles (non-colored particles) are appropriately subjected to various treatments so as to be properly distinguished from the background. The brightness below the binarization threshold is judged as a particle, and the brightness above the binarization threshold is judged as a background.

Particles (non-zero points) are cut out from the background (zero points) based on the binarized image separated in this way, but by performing appropriate expansion and contraction processing, isolated points in the particles can be removed and contour irregularities can be smoothed. It is possible. It is also possible to trace the contours and determine the contours of the particles. Using this binarized image or contour image, a particle image is cut out from the grayscale image immediately before binarization to obtain a particle image, and the average brightness of the grayscale image of the internal pixels is calculated to calculate the particles. It is calculated as the average brightness of.

Then, the non-colored particles in the toner are particles having high brightness (the average brightness of the particles is 90 or more) by a measuring machine such as FPIA.

Further, the “high-luminance particle size particle size Dv50 [μm] average brightness ↑ 90 in the toner” in Table 6 is the particle size Dv50 [μm] of the non-colored particles having a brightness of 90 or more. The "coloring ratio (Fc / Fm)" in Table 5 is the ratio of the "colored particle fine powder ratio Fc" to the "non-colored particle mixed product fine powder ratio Fm (pop ↓ 2 μm)".

Further, in Table 4, the mixed particles of the symbols T15S1 and T15S2 (Examples 12 and 13) were prepared by filming 2 parts by weight of the non-colored particles of the symbol T15 (Example 9). In the filming treatment, the peripheral speed at the outermost periphery of the rotary stirring means in the flow device used in the encapsulation step P52 (film formation treatment step) is set to 80 m / sec for the mixed particles of the symbol T15S1 and 100 m / sec for the mixed particles of the symbol T15S2. It was set to sec, and the flow time was set to 300 seconds for the mixed particles of the symbol T15S1 and 300 seconds for the mixed particles of the symbol T15S2. The temperature inside the flow device was 60 ° C. or higher in the market.

Further, in Table 4, the mixed particles of the symbols T22C1 and T22C2 (Example 14, Comparative Example 4) were prepared by classifying 2 parts by weight of the non-colored particles of the symbol T22 (Example 1) by a classifying device. Is. A wind power classifier (manufactured by Hosokawa Micron Co., Ltd.) was used as the classifying device.

[6] External attachment process P6
In the external addition step P6, 2 parts of hydrophobic silica particles (manufactured by Aerosil Co., Ltd., primary particle size 12 nm, HMDS treatment) are charged into 100 parts by weight of the produced mixed particles, and the stirring blade described above is used. The mixture was mixed at a peripheral speed of 30 m / sec for 1 minute, and then the toner passed through a mesh having a mesh opening of 45 μm was collected and used as a toner for evaluation.

In this toner, the high-luminance particle ratio Wt in the toner and the fine powder ratio Ft in the toner were obtained, respectively, to obtain the high-luminance particle ratio (Ft / Wt).

[Image evaluation]
The toner described above and a ferrite core carrier having a volume average particle diameter of 40 μm were mixed so that the toner concentration was 8% to prepare a two-component developer.

In the initial evaluation, "image evaluation" of the degree of "white spots" and the degree of "black spots" was carried out at the initial stage by using the above-mentioned two-component developer.

Further, in the "stability evaluation", the cartridge was filled so that the same toner as the toner used to prepare the two-component developer was replenished.

Using a modified commercial copier (trade name: MX-4500, manufactured by Sharp Corporation)
Confirmation of Examples and Comparative Examples was carried out. Evaluation was performed using recording paper (trade name: PPC paper SF-4AM3, manufactured by Sharp Corporation), which is a recording medium. It was measured using an initial image density measurement color difference meter (trade name: X-Rite938, manufactured by X-Rite).

In the "initial evaluation", "image evaluation" of the degree of "white spots" and the degree of "black spots" was performed at the initial stage. In the "stability evaluation", the degree of fog (print resistance fog) in "low printing" with low toner consumption and the degree of fog (life fog) in "high printing" with high toner consumption were evaluated. ..

"Initial evaluation"
For the image quality evaluation in the initial evaluation, "evaluation of white spots (missing images)" and "evaluation of black spots (aggregates)" were performed. First, the developing potential was adjusted to an image density such that ID (image density) ≈1.3 in the solid portion. In addition, in each of the Examples and Comparative Examples, the potential and the cleaning field are adjusted so that large fog does not occur in the initial printing (more than the range of fog "○"). It should be noted that what is used here is to charge the photoconductor by a corona charging method using a grid electrode, so that the surface potential becomes almost uniform. Regarding the "stability evaluation" described later, the transition from this condition was confirmed.

In the "white spot (image omission) evaluation", the center of the printed image of the patch having a diameter of 10 mm was visually observed with a loupe having a magnification of 200 times, and the number of uncolored portions in the patch was determined. The number of "white spots" was 0 for "⊚", 1 for "○", 2 to 3 for "Δ", and 4 or more for "x".

In the "black spot (aggregate) evaluation", a solid black image is printed with the ratio of the image portion (printing portion) to the entire A4 size paper being 100%, and the number of large aggregates that can be visually confirmed in the solid image. Was counted. The number of "black dots" was 0 for "⊚", 1 for "○", 2 to 3 for "Δ", and 4 or more for "x".

"Stability evaluation (fog)"
(Print resistant fog)
"Low printing" (ratio 1%) was a print resistance test for printing with a printing area (image area) of 1% (non-image area 99%) on A4 paper. In a high humidity environment (room temperature 25 ° C., humidity 80%), 2,000 sheets of "low printing" were performed, left overnight, and a fog test was carried out the next day.

In the printing endurance test in "low printing", since the non-image area is wide, fine particles are consumed by contact with the photoconductor drum. In particular, since the back-charged toner is developed in the non-developed region, the consumption of fine particles increases. Furthermore, since the toner is not replenished so much, the replenishment of non-colored particles to the developer does not proceed, and the conditions become stricter.

(Life fog)
"High printing" (ratio 20%) was a printing endurance test in which 20,000 sheets were printed with a printing area (image area) of 20% (non-image area 80%) on A4 paper and toner was consumed. In a high humidity environment (room temperature 25 ° C., humidity 80%), 20,000 sheets of "high printing" were performed, left overnight, and the next day, a fog test was carried out by a charging method using a grid electrode.

In the printing endurance test in "high printing", a large amount of toner is replenished, so that a load is applied to the carrier, and as a result, the charging ability of the carrier is lowered and fog is likely to occur.

(Fog evaluation)
In "fog evaluation", the whiteness of a specific position on the paper before printing is measured in advance using a whiteness meter (product name: manufactured by Nippon Denshoku Industries Co., Ltd.), and after printing at the same position (non-image area). Alternatively, it was evaluated by measuring the difference between the whiteness of (image area 0%) and the whiteness after printing (non-image area). If the difference in whiteness is 0.3 or less, it is "◎", if it is more than 0.4 and 0.8 or less, it is "○", and if it is more than 0.8 and 1.2 or less, it is "△". When it exceeds 1.2, it is marked with "x".

(comprehensive evaluation)
"Comprehensive evaluation" is the evaluation of "initial image quality" and "stability evaluation (fog)". If all are "○", then "○" and "×" are not included and "△" is included. Was "△", and if there was even one "x", it was set as "x".

From the "evaluation of black spots (aggregates)", if the volume average particle size of the non-colored particles exceeds 5.4 μm, image omission is likely to occur. Therefore, as shown in Examples 1 to 14 shown in Table 6, the toner preferably has a volume average particle size of 5.4 μm or less of the non-colored particles. By doing so, it is possible to suppress the occurrence of image omission.

Further, even if the volume average particle size of the non-colored particles is 5.4 μm or less, the toner is a positively charged non-colored particles WF6 to WF7 (Tables 4 and Table) as non-colored particles as in Comparative Examples 2 and 3. If the particles (see 2) are used, the chargeability is different from that of the colored particles, so that aggregates are generated and black spots (aggregates) are generated.

Further, as shown in Examples 1 to 14 shown in Table 4, the amount of the non-colored particles added to the toner is in the range of 1 part by weight to 7 parts by weight with respect to 100 parts by weight of the colored particles. preferable. By doing so, the colored particles and the non-colored particles can be appropriately mixed while suppressing the degree of fog.

Further, as shown in Examples 1 to 14 shown in Table 6, the high-luminance particle ratio Wt (average brightness ↑ 90) in the toner, which is the ratio of non-colored particles in the toner, is in the range of more than 4% and 37% or less. , Preferably in the range of 10% to 28%, more preferably in the range of 14% to 23%. By increasing the amount of non-colored particles added when the high-luminance particle ratio Wt (average brightness ↑ 90) in the toner is 37% or less, fog during printing resistance, especially "print resistance fog" during low printing, is improved. be able to. Further, even when the amount of non-colored particles added is reduced, it is preferable that the high-luminance particle ratio Wt (average luminance ↑ 90) in the toner exceeds 4%. When the ratio of non-colored particles decreases, the effect of suppressing fog decreases. For example, as in Comparative Example 4, when it is reduced to 4%, the fog suppression effect is reduced.

Further, as shown in Examples 1 to 14 shown in Table 6, the fine particle ratio (pop ↓ 2 μm) in the toner, which is the ratio of the particle size to the frequency distribution based on the number of the number in the toner, is 2 μm or less, is set to Ft, and is not in the toner. Assuming that the ratio of high-intensity particles in the toner (average brightness ↑ 90), which is the ratio of colored particles, is Wt, the ratio of high-intensity particles (Ft / Wt) to the ratio of high-intensity particles in the toner, which is the fine powder ratio Ft in the toner, is , 0.79 ≦ (Ft / Wt) ≦ 1.43. The anti-fog effect in such low printing is exhibited by charging the non-colored particles with the same polarity as the colored particles. Furthermore, the effect is limited only by the large number of non-colored particles, and it is exhibited by the small particle size of the high-luminance particles.

Further, as shown in Examples 1 to 14 shown in Table 5, in the mixed particles when the colored particles and the non-colored particles are mixed, the colored particles having a particle size ratio of 2 μm or less with respect to the frequency distribution based on the number of colored particles. The fine powder ratio (pop ↓ 2 μm) is defined as Fc (see Table 4), and the fine powder ratio (pop ↓ 2 μm) of the non-colored particle mixed product, which is the ratio of the particle size in the mixed powder of the colored particles and the non-colored particles to 2 μm or less. Assuming Fm, the coloring ratio (Fc / Fm) of the colored particle fine powder ratio Fc (pop ↓ 2 μm) to the non-colored particle mixture fine powder ratio Fm (pop ↓ 2 μm) is 0.13 ≦ (Fc / Fm). It is preferable to satisfy the relationship of ≦ 0.65. By doing so, the ratio of the colored particles can be suppressed with respect to the non-colored particles, and thereby the degree of fog can be further suppressed. The anti-fog effect in such low printing is exhibited by charging the non-colored particles with the same polarity as the colored particles. Furthermore, the effect is limited only by the large number of non-colored particles, and it is exhibited by the small particle size of the high-luminance particles. These effects are also exhibited when the high-luminance particle ratio Wt in the toner is reduced by applying an operation after mixing the colored particles, but when the high-luminance particle ratio Wt falls below 9.3%, The effect will be limited.

Further, as in Examples 1 to 14, a plurality of pixels corresponding to the plurality of mixed particles are formed based on the image data obtained by imaging a plurality of mixed particles obtained by mixing the colored particles and the non-colored particles. The average value of the brightness values is calculated as the average brightness, the frequency distribution based on the number of average brightness for a plurality of imaged mixed particles is obtained, and the particles whose average brightness is equal to or higher than the predetermined brightness from the obtained frequency distribution are defined as non-colored particles. It is preferable to do so. By doing so, the non-colored particles can be reliably determined.

Further, as in Examples 1 to 14, the ratio of high-luminance particles in the toner (average brightness ↑ 90), which is the ratio of non-colored particles in the toner, is adjusted with the toner after mixing the colored particles and the non-colored particles. It is preferable to adjust. By doing so, it is possible to obtain a desired high-luminance particle ratio (average brightness ↑ 90) in the desired toner after mixing the colored particles and the non-colored particles.

Further, as in Examples 12 and 13, it is preferable to fix fine particles containing non-colored particles (high-intensity particles) to the colored particles by a film-forming treatment by encapsulation. By doing so, the amount of fine powder can be adjusted, and therefore, the stability of the fog suppression effect in "print-resistant fog" and "life fog" can be improved.

Although the toner according to the present embodiment is applied to the two-component developer, it may be applied to the one-component developer containing only the toner that does not contain a carrier.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Therefore, such embodiments are merely exemplary in all respects and should not be construed in a limited way. The scope of the present invention is shown by the claims and is not bound by the text of the specification. Furthermore, all modifications and modifications that fall within the equivalent scope of the claims are within the scope of the present invention.

10 Photoreceptor 10a Surface P1 Transparent particle preparation step P2 Non-colored particle preparation step P3 Colored resin composition preparation step P4 Colored particle preparation step P41 Melt kneading step P42 Crushing step P43 Classification step P5 Mixed particle preparation step P51 Mixing step P52 Encapsulation step P6 External step S Transfer material T Toner Ta Colored particles Ta1 Surface Tb Non-colored particles Tb1 Surface Tc External agent Ti Toner image α Charged area β Electrostatic latent image β1 Developed area β2 Undeveloped area γ1 Image area γ2 Non-image area

Claims (10)

A toner in which a plurality of colored particles containing a colorant and a binder resin and a plurality of non-colored particles not containing a colorant are mixed.
The colored particles and the non-colored particles are charged with the same polarity,
A toner characterized in that the volume average particle size of the non-colored particles is smaller than the volume average particle size of the colored particles. The toner according to claim 1.
A toner characterized in that the volume average particle diameter of the non-colored particles is 5.4 μm or less. The toner according to claim 1 or 2.
A toner characterized in that the amount of the non-colored particles added to the toner is in the range of 1 part by weight to 7 parts by weight with respect to 100 parts by weight of the colored particles. The toner according to any one of claims 1 to 3.
A toner characterized in that the ratio of high-luminance particles in the toner, which is the ratio of the non-colored particles in the toner, is in the range of more than 4% and 37% or less. The toner according to any one of claims 1 to 4.
Let Ft be the fine powder ratio in the toner having a particle size ratio of 2 μm or less with respect to the frequency distribution based on the number of pieces in the toner, and Wt be the ratio of high-luminance particles in the toner which is the ratio of the non-colored particles in the toner. The high-luminance particle ratio (Ft / Wt) with respect to the high-luminance particle ratio Wt in the toner of the fine powder ratio Ft in the toner is characterized by satisfying the relationship of 0.79 ≦ (Ft / Wt) ≦ 1.43. Toner. The toner according to any one of claims 1 to 5.
The percentage of colored particle fine particles, which is the ratio of the particle size to the frequency distribution based on the number of colored particles, is Fc, and the ratio of the particle size in the mixed powder of the colored particles and the non-colored particles is 2 μm or less. Assuming that the fine particle ratio of the colored particle mixture is Fm, the coloring ratio (Fc / Fm) of the colored particle fine powder ratio Fc to the non-colored particle mixed product fine powder ratio Fm is 0.13 ≦ (Fc / Fm) ≦ 0.65. A toner characterized by satisfying the relationship of. A two-component developer comprising the toner according to any one of claims 1 to 6 and a carrier. A method for producing a toner according to any one of claims 1 to 6, wherein the toner is produced.
The transparent particle preparation process for preparing transparent particles,
A non-colored particle preparation step for preparing non-colored particles from the transparent particles prepared in the transparent particle preparation step, and a non-colored particle preparation step.
The process of producing a colored resin composition and the process of producing a colored resin composition,
A colored particle preparation step of preparing colored particles from the colored resin composition prepared in the colored resin composition manufacturing step, and a colored particle preparation step of preparing colored particles from the colored resin composition.
A mixed particle preparation step of mixing the non-colored particles prepared in the non-colored particle preparation step and the colored particles prepared in the colored particle preparation step to prepare mixed particles.
A method for producing a toner, which comprises. The method for producing toner according to claim 8.
Based on the image data obtained by imaging a plurality of mixed particles obtained by mixing the colored particles and the non-colored particles, the average brightness of the brightness values of the plurality of pixels corresponding to the plurality of mixed particles is averaged. The frequency distribution based on the number of average brightness for the plurality of mixed particles imaged is obtained, and the particles whose average brightness is equal to or higher than a predetermined brightness from the obtained frequency distribution are defined as the non-colored particles. How to manufacture toner. The method for producing toner according to claim 8 or 9.
A method for producing toner, which comprises adjusting the ratio of high-luminance particles in the toner, which is the ratio of the non-colored particles in the toner, with the toner after mixing the colored particles and the non-colored particles.

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