JP6089726B2 - Toner for developing electrostatic charge, developer for developing electrostatic image, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner, an electrostatic charge image developing developer, and an image forming apparatus that are excellent in storage stability, low-temperature fixability, and the like, and excellent in image quality with little fogging and the like.

Generally, toner used in electrophotographic copying machines and printers is a mixture composed of a plurality of substances such as a colorant, a release agent, and a charge control agent with a binder resin as a main component. . In the pulverized toner, these raw materials are usually melt-kneaded, and the melt-kneaded product is pulverized and classified to obtain a toner having a desired particle size.
The proportion of the binder resin in the raw materials constituting the toner usually accounts for 80 to 90% by weight, and most of the components in the toner are plastics. In recent years, measures have been taken to reduce the content and use of plastics as much as possible for plastic products in order to reduce environmental burdens, waste, and incineration disposal loads of local governments. As a method of reducing the content of plastics, for example, in a plastic bag or the like, there is a method of adding a filler such as calcium carbonate. This method is used in many plastic products because it can reduce the content of plastics and can greatly reduce the cost of the products.
Similarly, in the toner, if the use amount of the binder resin and other toner raw materials can be reduced by using a filler or the like, there is a possibility of reducing the environmental load and drastically reducing the cost.

JP-A-63-139364 of Patent Document 1 discloses calcium carbonate, magnesium oxide, and magnesium hydroxide particles for positive charging, and silicon dioxide, aluminum silicate, aluminum hydroxide, and silicic acid for negative charging. An electrostatic charge developing toner containing zirconium particles is described, and Japanese Patent Application Laid-Open No. 2004-361663 of Patent Document 2 contains at least a binder resin and a black metal oxide as a colorant, and is carbonated during melt kneading. A toner for developing an electrostatic charge image is disclosed, comprising a powder obtained by pulverizing and classifying a kneaded product obtained by containing calcium. In this patent publication, it is disclosed that 0.01 to 10% by weight of calcium carbonate is preferably added to the toner. However, when an inorganic filler such as calcium carbonate is added to the toner, the melt viscosity of the toner increases, which may deteriorate the low-temperature fixability and the toner grindability. A decrease in toner pulverization property and a decrease in low-temperature fixability are not preferable from the viewpoint of reducing the environmental load.
Therefore, in order to improve the low-temperature fixability and grindability of the toner, there is usually a method of reducing the thermal characteristics such as the glass transition temperature and flow softening temperature of the binder resin. Therefore, there is a possibility that a toner pressure piece or an agglomerate may be generated to cause a reduction in image quality. In addition, the charging performance of the toner may be significantly degraded due to poor dispersion of calcium carbonate, exposure to the toner surface, and the like, leading to a decrease in image quality.

Japanese Patent Application Laid-Open No. 2007-011347 of Patent Document 3 discloses a toner including toner particles including a binder, at least one colorant, and silicate particles distributed in the binder. Further, this document describes a method for improving the relative humidity dependency of the toner by including silicate particles in the binder.
However, when silicate clay particles are added to the toner, the melt viscosity of the toner increases like calcium carbonate, which may deteriorate the low-temperature fixability or the toner pulverization. Further, the charging ability of the toner may be reduced due to the influence of poor dispersion of silicate particles, exposure of the toner surface, and the like. In the emulsion aggregation toner, the silicate clay particles are easily included in the toner, but in the pulverized toner, the silicate clay particles are easily exposed on the surface in the process of pulverizing the melt kneaded material of the toner raw material, and the toner charging ability is improved. There is a risk that it may lead to deterioration or deterioration of image quality.

  An object of the present invention is to provide a toner that is excellent in storage stability, low-temperature fixability and the like, and excellent in image quality with little fogging. Another object of the present invention is to provide a toner that is inexpensive and excellent in productivity.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor has found that the toner contains at least a binder resin, a colorant, and at least one inorganic filler selected from calcium carbonate, kaolin clay, talc, and barium sulfate. A toner for developing an electrostatic image obtained from a toner material, wherein the toner has a glass transition temperature in the range of 50 to 58 ° C., and the content of the inorganic filler is 100 parts by weight of the toner. 1 to 10 parts by weight, a part of the inorganic filler is present on the toner surface, and the proportion of the inorganic filler present on the surface of the toner base particles is in the range of 5 to 40% with respect to the content of the inorganic filler. The toner is characterized by having excellent storage stability, low-temperature fixability, etc., low fog, excellent image quality, low cost, and excellent productivity. Heading the Rukoto, it has led to the completion of the present invention.

That is, the present invention includes the following “electrostatic charge developing toner”, “electrostatic image developer”, and “image forming apparatus”.
(1) An electrostatic image developing toner obtained from a toner material containing at least a binder resin, a colorant, and one or more inorganic fillers selected from calcium carbonate, kaolin clay, talc, and barium sulfate. The toner has a glass transition temperature in the range of 50 to 58 ° C., and the content of the inorganic filler is 1 to 10 parts by weight with respect to 100 parts by weight of the toner. A toner for developing an electrostatic charge image, wherein the toner is present on the surface of the base particle, and the proportion of the inorganic filler existing on the surface of the toner base particle is in the range of 5 to 40% with respect to the content of the inorganic filler. . "
(2) “The toner for developing an electrostatic charge image according to (1), wherein the inorganic filler has a number average particle diameter of 0.1 to 10 μm.”
(3) The item (1) or (2), wherein the inorganic filler is surface-treated with one or more kinds of treatment agents selected from silane coupling agents, surfactants, and metal soaps. The toner for developing an electrostatic image according to 1.
(4) The electrostatic image development according to any one of items (1) to (3), wherein the binder resin includes a binder resin having a glass transition temperature of 48 ° C. to 55 ° C. toner."
(5) “The electrostatic charge image developing toner according to any one of items (1) to (4), wherein the binder resin includes a polyester resin”.
(6) Any one of the above items (1) to (5), wherein the toner material is obtained by melt-kneading the toner material and pulverizing and classifying the obtained melt-kneaded product. Toner for developing electrostatic image. "
(7) “The binder resin includes a binder resin contained in toner base particles granulated in an aqueous medium,” according to any one of (1) to (5), Toner for electrostatic image development. "
(8) “One-component developer for electrostatic image, comprising toner base particles of toner for developing electrostatic image according to any one of items (1) to (5) and an external additive” . "
(9) “A two-component developer for electrostatic images, comprising toner base particles and carrier particles of the toner for developing electrostatic images according to any one of items (1) to (5). "
(10) “An image forming apparatus comprising a developing unit equipped with the developer according to item (8) or (9)”.

  The toner of the present invention is a toner that has solved the above-described problems, and includes at least a binder resin, a colorant, and at least one inorganic filler selected from calcium carbonate, kaolin clay, talc, and barium sulfate. The toner for developing an electrostatic charge image obtained from the above, wherein the toner has a glass transition temperature in the range of 50 to 58 ° C., and the content of the inorganic filler is 1 to 10 with respect to 100 parts by weight of the toner. Part of the inorganic filler is present on the surface of the toner base particle, and the proportion of the inorganic filler present on the surface of the toner base particle is in the range of 5 to 40% with respect to the content of the inorganic filler. Therefore, it is possible to obtain a toner that is excellent in low-temperature fixability, storage stability and the like, and excellent in image quality with little fogging. In addition, since the toner of the present invention can be produced at low cost and has excellent productivity, it is possible to reduce environmental loads such as waste reduction, energy use load reduction, and carbon dioxide emission reduction.

As described above, the toner of the present invention is a static material obtained from a toner material containing at least a binder resin, a colorant, and one or more inorganic fillers selected from calcium carbonate, kaolin clay, talc, and barium sulfate. A toner for developing a charge image, wherein the toner has a glass transition temperature in the range of 50 to 58 ° C., and the content of the inorganic filler is 1 to 10 parts by weight with respect to 100 parts by weight of the toner. Is partly present on the surface of the toner base particles, and the ratio of the inorganic filler present on the surface of the toner base particles is in the range of 5 to 40% with respect to the content of the inorganic filler. These may be “pulverized toners” or so-called “chemical toners”. However, in the case of pulverized toners, the proportion of the inorganic filler present on the surface of the toner base particles is the content of the inorganic filler. On the other hand, there is an advantage that a product within the range of 5 to 40% is relatively easy to manufacture. Therefore, the following description will mainly focus on “pulverized toner”, but the present invention can be applied to the case of chemical toner as well as “pulverized toner”.
Various inorganic fillers such as silica, alumina, titanium oxide, cryolite, zinc oxide, bentonite, (sub-) iron oxide, molybdenum disulfide, magnesium hydroxide and the like are known. However, the first important point in the present invention is that these are not suitable, and only a limited one selected from calcium carbonate, kaolin clay, talc and barium sulfate is preferably used. Further, the toner according to the present invention has a relatively low-temperature fusibility with a glass transition temperature in the range of 50 to 58 ° C., and is excellent in storage stability.
Further, as a remarkable feature point, it is possible to obtain a high-quality image with little fogging.
The present invention will be described in detail below.

First, at least a binder resin, a colorant, and at least one inorganic filler selected from calcium carbonate, kaolin clay, talc, and barium sulfate are blended in a predetermined ratio and mixed.
Next, after the mixture is melt-kneaded, the obtained melt-kneaded product is pulverized and classified to obtain the toner of the present invention. The toner raw materials in the present invention are not particularly limited, and known materials can be used.
The binder resin is not particularly limited as long as it is a resin that can be fixed on a medium such as paper, but a homopolymer of styrene such as polystyrene, poly (p-chlorostyrene), polyvinyltoluene, and the like; and styrene-p-chloro. Styrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer , Styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene -Acrylonitrile-indene copolymer, etc. Polyethylene chloride; Phenol resin; Naturally modified phenolic resin; Natural resin modified maleic acid resin; Acrylic resin; Methacrylic resin; Polyvinyl acetate; Silicone resin; Polyester resin; Polyurethane resin; Examples include epoxy resins; xylene resins; polyvinyl butyral; terpene resins; coumarone indene resins; petroleum resins. These resins may be used alone or in combination of two or more. Among these, polyester resins and styrene copolymers are preferable, and polyester resins can be preferably used from the viewpoints of low temperature fixability and dispersibility of inorganic fillers.

  The polyester resin is obtained by condensation polymerization of alcohol and carboxylic acid. Examples of the alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butanediol, neopentyl glycol, 1,4 -Diols such as butenediol, 1,4-bis (hydroxymethyl) cyclohexane, and etherified bisphenols such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. Mention may be made of divalent alcohol monomers. These alcohols may be used alone or in combination of two or more.

  Examples of the carboxylic acid include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, Examples thereof include anhydrides of these acids, dimers of lower alkyl esters and linolenic acid, and other divalent organic acid monomers. These carboxylic acids may be used alone or in combination of two or more.

  The polyester resin may be a polymer containing not only a polymer composed of only a bifunctional monomer but also a component composed of a trifunctional or higher polyfunctional monomer. Examples of trihydric or higher polyhydric alcohol monomers that are polyfunctional monomers include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, Tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri Mention may be made of methylolpropane, 1,3,5-trihydroxymethylbenzene and other trihydric or higher polyhydric alcohol monomers.

The glass transition temperature (Tg) of the binder resin is usually in the range of 45 ° C to 75 ° C, preferably 45 ° C to 60 ° C, more preferably 48 ° C to 60 ° C, particularly 48 ° C to 55 ° C. is there.
Since the toner of the present invention contains an inorganic filler, even when the glass transition temperature of the binder resin is within the above range, the toner has excellent storage stability and excellent low-temperature fixability. When the glass transition temperature of the binder resin is lower than 45 ° C., the storage stability of the toner is deteriorated, and when it is higher than 75 ° C., the low-temperature fixability is deteriorated and the grindability is also deteriorated.

  The binder resin of the present invention may contain a binder resin contained in toner particles granulated in an aqueous medium. The method for producing toner particles granulated in an aqueous medium can be selected from suspension polymerization, emulsion polymerization aggregation, dissolution suspension, ester extension polymerization and the like. The toner produced by these production methods is excellent in low-temperature fixability. In the toner containing the inorganic filler of the present invention, the toner having excellent low-temperature fixability by including a binder resin contained in these toner particles. Can be obtained.

In the present invention, the inorganic filler can be added singly or in combination of at least one selected from calcium carbonate, kaolin clay, talc, and barium sulfate. These inorganic fillers may be surface-treated with a silane coupling agent, a surfactant, a metal soap, or the like, or those adjusted to a desired particle size distribution by classification or the like may be used.
Kaolin clay is mainly composed of aluminum silicate, and usually contains components such as aluminum hydroxide, magnesium hydroxide and water. Kaolin clay includes hydrous kaolin, calcined kaolin, and surface-treated kaolin that has been surface-treated with stearic acid, a silane coupling agent, a surfactant, and the like, and any of them can be used without any particular limitation. From the viewpoint of economy, the use of hydrous kaolin is preferred, and from the viewpoint of image quality and toner environmental stability, the use of calcined kaolin or surface-treated kaolin is preferred. The particle diameter of kaolin is usually 0.1 to 10 μm, preferably 0.3 to 3 μm, more preferably 0.3 to 1 μm. If the particle size is 10 μm or more, it will be larger than the toner particle size, so it will be difficult to encapsulate it in the toner. There is a risk of inviting. Further, if the particle diameter is 0.1 μm or less, the cost is high and this is not preferable economically.

Examples of calcium carbonate include heavy calcium carbonate, light calcium carbonate, surface-treated calcium carbonate surface-treated with stearic acid, silane coupling agent, surfactant, etc., and any of them can be used without particular limitation. It is. Heavy calcium carbonate is divided into dry heavy calcium carbonate and wet heavy calcium carbonate by a pulverization method, and the particle size is usually 0.5 to 10 μm, preferably 0.5 to 3 μm, more preferably 0.5. ˜1 μm. If the particle size is 10 μm or more, it is larger than the toner particle size, so it is difficult to encapsulate the toner in the toner. There is a risk of inviting. Further, when the particle diameter is 0.5 μm or less, the cost is high and this is not preferable economically. Light calcium carbonate is produced by a chemical process, and the particle shape is usually spindle-shaped or columnar, and can be used without any particular limitation. The particle diameter of light calcium carbonate is usually 0.05 to 5 μm, preferably 0.1 to 3 μm, and more preferably 0.1 to 1 μm. When the particle diameter is 5 μm or more, it is difficult to encapsulate the toner particles, and when the particle diameter is 0.05 μm or less, it is difficult to uniformly disperse the toner particles, which may cause a reduction in toner quality.
Talc is composed of a composite salt of magnesium oxide and silicic acid, and the particle diameter is usually 0.1 to 10 μm, preferably 0.3 to 3 μm, more preferably 0.3 to 1 μm.
If the particle size is 10 μm or more, it will be larger than the toner particle size, so it will be difficult to encapsulate it in the toner. There is a risk of inviting. Further, if the particle diameter is 0.1 μm or less, the cost is high and this is not preferable economically. Barium sulfate is generally pulverized barite mineral (barite powder) called natural barite and precipitated barium sulfate produced by chemical process. Any of these can be used without any particular restrictions. It is. The particle diameter is usually 0.1 to 10 μm, preferably 0.3 to 3 μm, and more preferably 0.3 to 1 μm.
In summary, it can be said that the inorganic filler in the present invention preferably has a number average particle diameter of 0.1 to 10 μm.

The amount of the inorganic filler added is 1 to 10 parts by weight, preferably 3 to 10 parts by weight, particularly preferably 5 to 8 parts by weight, based on 100 parts by weight of the toner. When the added amount of the inorganic filler exceeds 10 parts by weight, the melt viscosity of the toner increases and the low-temperature fixability deteriorates.
Furthermore, the amount of the inorganic filler exposed to the toner surface increases, and the toner charge amount may decrease, leading to a decrease in image quality. Further, it becomes difficult to uniformly disperse in the binder resin, and there is a possibility that the toner quality is deteriorated. On the other hand, when the added amount of the inorganic filler is less than 1 part by weight, the toner storage stability is deteriorated, and it is difficult to achieve both low-temperature fixability and storage stability.

Further, a part of the inorganic filler needs to be present on the surface in the process of pulverizing and classifying the toner. The presence of the inorganic filler on the surface makes it possible to obtain a toner having excellent storage stability. The proportion of the inorganic filler present on the toner surface (surface presence ratio) is preferably 5 to 40%, more preferably 5 to 35%, and particularly preferably about 10 to 30% with respect to the content of the inorganic filler. It is.
In the present invention, the surface abundance ratio of the inorganic filler on the toner base particle surface reflects not only the suitability of the inorganic filler content and the degree of dispersion, but also the appropriate particle size of the inorganic filler relative to the toner base particles. is there. In other words, the surface area S of one toner base particle having an average radius r and the volume V of the same base particle have a relationship of S = 4πr ² and V = (4/3) πr ³ . Assuming that 100 inorganic fillers are completely dispersed in one base particle having an average volume V, the average distance L between the inorganic filler particles dispersed in the vertical, horizontal and oblique random directions is: This is a function of the total number N of inorganic filler fine particles dispersed and the volume v of each inorganic filler fine particle. It can be considered that v = V / N and L = v ^1/3 . This idea is basically the same even if L >> v, only the space where v does not exist increases.
The average distance L between the 100 inorganic filler particles dispersed in the volume V is calculated to be about 1,6117r from the above expression (even if the influence of v is ignored). Of these 100, the number appearing on the surface of the parent sphere is 100 × 1 / 3r. That is, “the number of inorganic filler particles appearing on the surface decreases as the base particle radius r becomes relatively larger”, which is in a negative proportional relationship with the radius r compared to the inorganic filler fine particle volume v, and is a proportional constant. Is 1/3. Suppose that r = 5 (thus V = 523, S = 314), N = 100, v total = 10 / V, 52.3 (the radius of the inorganic filler fine particles is 1.612), and a completely dispersed state. Then, the number% of inorganic filler particles observed on the base particle surface is 100 × 1/3 × (5 / 1.612) = 7.2%. Then, the average distance L ′ when observed as an area, that is, two-dimensionally, is the three-dimensional average distance L, L ′ = (L ^1/2 / Lr ^1/3 ) = 0.899 L × (1/2) ≈0.45. These are, of course, temporary provisions for easy understanding of the present invention. When comparing the surface abundance ratio of the surface of the toner base particles of the inorganic filler in the specific examples described later with these temporary values, the content of the inorganic filler of the present invention, the degree of dispersion, and the particle size of the inorganic filler You can understand how the point makes the present invention superior.
When the surface presence rate of the inorganic filler is larger than 40%, the charge amount of the toner is lowered, and the image quality such as fog is likely to be deteriorated. When the surface content of the inorganic filler is less than 5%, the storage property tends to be lowered because the amount of the inorganic filler present on the toner surface is small. The presence of the inorganic filler on the toner surface makes it possible to achieve both storage stability and low-temperature fixability.
The state in which the inorganic filler is present on the toner surface may be a state in which particles of the inorganic filler are attached to the surface of the toner, and the inorganic filler is embedded in the toner base. However, any of the embedded inorganic fillers may be exposed on the toner surface.

  The presence of the inorganic filler surface can be confirmed, for example, by confirming the toner surface with an electron microscope image. Further, the surface abundance ratio (surface abundance ratio) of the inorganic filler can be obtained from a Fourier transform infrared spectrophotometer (FT-IR), and the surface presence of the inorganic filler is determined from the intensity of the infrared absorption spectrum caused by the inorganic filler. The rate can be calculated. In this case, an inorganic filler quantified in advance is attached to the toner surface, and the infrared absorption spectrum intensity is measured to confirm the relationship between the inorganic filler surface abundance and the infrared absorption spectrum intensity.

As the colorant used in the toner of the present invention, a black pigment for black toner, a magenta pigment, a cyan pigment, a yellow pigment and the like for color toner can be used.
As the black pigment, usually carbon black can be used. Carbon black can be used without being limited by the number average particle diameter, oil absorption, PH, etc., and the following are commercially available products. For example, trade names manufactured by Cabot Corporation of the United States: REGAL 400, 660, 330, 300, SRF-S, STERLING SO, V, NS, R, product names manufactured by Columbia Carbon Japan Co., Ltd .: Raven H20, MT-P, 410, 420, 430, 450, 500, 760, 780, 1000, 1035, 1060, 1080, trade names manufactured by Mitsubishi Chemical Corporation: # 5B, # 10B, # 40, # 2400B, MA-100 Etc. can be used. These carbon blacks can be used alone or in combination of two or more. The ratio of carbon black to the toner weight can usually be selected from the range of 1 to 20 parts by weight, preferably 1 to 10 parts by weight, and more preferably 3 to 10 parts by weight. If the ratio of carbon black is too small, the image density is lowered, and if it is too much, the image quality is liable to be lowered and the toner moldability is also lowered. As a black pigment, carbon black and black magnetic powder such as iron oxide and ferrite can be used.

Examples of the magenta pigment include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209; I. Pigment violet 19; C.I. I. Butlet 1, 2, 10, 13, 15, 23, 29, 35, etc. can be used. These magenta pigments can be used alone or in combination of two or more. Examples of cyan pigments include C.I. I. Pigment blue 2, 3, 15, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45 etc. can be used. These cyan pigments can be used alone or in combination of two or more.
As a pigment for yellow, C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 94, 97, 155, 180, etc. Can be used. These yellow pigments can be used alone or in combination of two or more.

  As a color pigment for full color, magenta pigment is C.I. from the viewpoint of color mixing and color reproducibility. I. Pigment Red 57 and 122 are cyan pigments such as C.I. I. Pigment Blue 15 is yellow pigment, C.I. I. Pigment Yellow 17, 83, 155, and 180 can be preferably used. The proportion of the color pigment can usually be selected from the range of 1 to 20 parts by weight, preferably 3 to 10 parts by weight, and more preferably 4 to 9 parts by weight with respect to 100 parts by weight of the toner. If the ratio of these pigments is less than the above range, the image density is lowered.If the ratio is too large, the dispersibility of the pigment is deteriorated, the color reproducibility is deteriorated, the stability of the toner charge amount is also deteriorated, and the image quality is improved. It tends to decline. It is also disadvantageous in terms of cost.

A charge control agent can be used in the toner of the present invention as necessary. Depending on the charging characteristics of the toner, the charge control agent may be a negatively chargeable charge control agent, a positively chargeable charge control agent, or an appropriate combination thereof.
Examples of positively chargeable charge control agents include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, Diorganotin oxide such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, diorganotin borate such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate, pyridium salt, azine, triphenylmethane compounds and cationic functional groups And low molecular weight polymers. These positively chargeable charge control agents may be used alone or in combination of two or more. As these positively chargeable charge control agents, nigrosine compounds and quaternary ammonium salts are preferably used.

Examples of negatively chargeable charge control agents include acetylacetone metal complexes, monoazo metal complexes, organometallic compounds such as naphthoic acid or salicylic acid-based metal complexes or salts, chelate compounds, and low molecular weight polymers having an anionic functional group. It is done. These negatively chargeable charge control agents can be used alone or in combination of two or more. As these negatively chargeable charge control agents, salicylic acid metal complexes and monoazo metal complexes are preferably used.
The addition amount of the charge control agent can usually be selected in the range of 0.1 to 5% by weight, preferably 0.3 to 4% by weight, and more preferably 0.5 to 4% by weight with respect to 100 parts by weight of the toner. %.
The charge control agent is preferably colorless or light color for color toners.

  Further, a release agent (waxes) may be added to the toner of the present invention as necessary. Release agents include polyolefin waxes such as polyethylene wax, polypropylene wax and modified polyethylene wax, synthetic waxes such as Fischer-Tropsch wax, petroleum waxes such as ester synthetic wax, paraffin wax and microcrystalline wax, carnauba wax and can Examples include vegetable waxes such as delila wax, rice wax, and hardened castor oil. These waxes can be used alone or in combination of two or more. The addition amount of the wax can be usually selected in the range of 0.1 to 10% by weight, preferably 0.5 to 7% by weight, and more preferably 1 to 5% by weight with respect to 100 parts by weight of the toner. When the amount of the wax added is too much above the above range, the dispersibility of the release agent is deteriorated, and the toner charging member and the carrier surface are contaminated and the image quality is liable to be lowered. If the amount is too small, the toner releasability becomes insufficient and the fixing characteristics deteriorate. Moreover, melting | fusing point of a mold release agent is 40-160 degreeC normally, Preferably, it is 50-120 degreeC, Furthermore, Preferably this is 60-90 degreeC. When the melting point of the release agent is less than 40 ° C., the storage stability of the toner is lowered, and when it exceeds 160 ° C., the fixing property of the toner may be lowered.

  The toner of the present invention may further include magnetic powder, for example, metals such as cobalt, iron, nickel, aluminum, copper, iron, nickel, magnesium, tin, zinc, gold, silver, selenium, titanium, tungsten as necessary. Zirconium, alloys of other metals, metal oxides such as aluminum oxide, iron oxide, nickel oxide, ferrite, magnetite and the like can be used. The addition amount of the magnetic powder is usually 1 to 70% by weight, preferably 5 to 50% by weight, and more preferably 10 to 40% by weight with respect to 100% by weight of the resin composition. A magnetic powder having an average particle diameter of 0.01 to 3 μm can be suitably used.

  The toner of the present invention further includes various additives as required, for example, stabilizers (for example, ultraviolet absorbers, antioxidants, heat stabilizers, etc.), flame retardants, antifogging agents, dispersants, cores. Agent, plasticizer (phthalate ester plasticizer, fatty acid plasticizer, phosphoric acid plasticizer, etc.), polymer antistatic agent, low molecular antistatic agent, compatibilizing agent, conductive agent, filler, fluidity improvement An agent or the like may be added.

The toner of the present invention preferably has inorganic fine particles attached to the surface. As inorganic fine particles, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide Inorganic compounds such as cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and magnetic powder. These inorganic fine particles may be used alone or in combination of two or more. Of these inorganic fine particles, silica and titanium oxide can be particularly preferably used. Further, the inorganic fine particles are not particularly limited, such as average particle diameter, BET specific surface area, presence or absence of surface treatment, and can be appropriately selected according to the use, but the BET specific surface area is preferably in the range of 50 to 400 m ² / g Those treated and hydrophobized are preferred. In addition, resin fine particles can be used together with the inorganic fine particles or in place of the inorganic fine particles.

  The ratio of adding these inorganic fine particles and resin fine particles to the toner can be appropriately selected from the range of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 100 parts by weight of the toner. Is 0.5 to 3 parts by weight. When the ratio to be added is out of the above range, the fluidity and chargeability of the toner are lowered, and it is difficult to form a uniform image, and the image quality is lowered.

The toner of the present invention can be obtained by mixing the raw materials at a predetermined ratio and then melt-kneading, and then pulverizing and classifying the melt-kneaded product. As a device for mixing the toner raw material, a known device can be used, and it is not particularly limited as long as the toner raw material can be mixed in a dry type. However, a gravity falling mixer such as a V blender or a ball mill, a super mixer (Kawata) ), Henschel mixer (Mitsui Mine), Q mixer (Mitsui Mine), Nobilta (Hosokawa Micron), etc. can be used. From the viewpoint of productivity and the like, a high-speed fluidized bed mixer such as a super mixer is preferable. Next, the mixed raw material mixture is melt-kneaded.
As a device used in melt kneading, a known device can be used, and any device capable of melting and kneading a raw material mixture is not particularly limited. However, a roll kneader such as a two-roll or a three-roll, a Banbury mixer or a press Examples thereof include a batch type closed kneader such as a kneader, a continuous closed kneader such as a single screw extruder and a twin screw extruder, and a continuous roll kneader. From the viewpoint of productivity, a continuous closed kneader such as a single screw extruder or a twin screw extruder or a continuous roll kneader is preferable.

  Next, the melt-kneaded product is cooled and solidified, and then a coarse pulverization step, a fine pulverization step, and a classification step are obtained to produce a toner. Known devices can be used for these processes. For example, a hammer mill, a cutter mill, etc. are used for the coarse pulverization process, and a high-speed rotary fine pulverizer, an airflow collision pulverizer, a fluidized bed pulverizer is used for the fine pulverization process. Etc. can be used. Further, for example, a forced vortex centrifuge or an inertia classifier is used in the classification process. The volume average particle diameter of the toner thus obtained is usually about 5 to 10 μm, preferably 6 to 9 μm, more preferably 6 to 8 μm. The volume average particle diameter is, for example, a 50% volume diameter measured using a particle size distribution measuring device such as Multisizer III (manufactured by Beckman Coulter). By obtaining the above steps, a toner having a desired particle size can be obtained. Usually, fine toner particles smaller than a predetermined particle size are generated in the classification step. The toner fine powder is usually returned to the mixing step from the viewpoint of productivity, and the toner fine powder is reused. When the toner fine powder is reused in the mixing step, the toner fine powder and each of the toner raw materials are mixed in the mixing step, and the mixture is obtained in a kneading step, a pulverizing step, and a classification step, and the toner is manufactured. Become.

  The thus obtained toner of the present invention has a glass transition temperature of 50 to 58 ° C, preferably 52 to 58 ° C, more preferably 54 to 58 ° C. When the glass transition temperature is higher than 58 ° C, the low-temperature fixability deteriorates, and when the glass transition temperature is lower than 50 ° C, the storage stability deteriorates. When the glass transition temperature is within the above range and the inorganic filler is present on the toner surface, both storage stability and low-temperature fixability can be achieved.

  Further, the use of the toner of the present invention is not particularly limited depending on the development method, and can be used in a non-magnetic one-component development method, a magnetic one-component development method, a two-component development method, and other development methods. The magnetic one-component developing system toner is used as a magnetic toner by mixing the magnetic powder described above in a binder resin, and the two-component developing system toner is used by mixing with a carrier.

As the carrier in the two-component development system, for example, nickel, cobalt, iron oxide, ferrite, iron, glass beads and the like can be used. These carriers may be used alone or in combination of two or more. The average particle size of the carrier is preferably 20 to 150 μm.
The surface of the carrier may be coated with a coating agent such as a fluorine resin, an acrylic resin, or a silicone resin.

The toner of the present invention may be a monochrome toner or a full color toner. In the monochrome toner, the above-described carbon black or the like can be used as the colorant, and in the full-color toner, the above-described one can be suitably used as the colorant. The toner of the present invention can be used particularly preferably in a monochrome toner from the viewpoint of color reproducibility and economical efficiency.
Although it does not specifically limit as a manufacturing method of a base particle, A grinding method, a polymerization method, etc. are mentioned.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The raw materials, toner physical property evaluation methods, and image property evaluation methods used in Examples and Comparative Examples are shown below.

[raw materials]
<Binder resin>
Binder resin (1): amorphous polyester resin for toner (glass transition temperature (Tg) = 58 ° C., flow softening temperature (T1 / 2) = 135 ° C.)
Binder resin (2): Amorphous polyester resin for toner (glass transition temperature (Tg) = 50 ° C., flow softening temperature (T1 / 2) = 103 ° C.)
Binder resin (3): styrene-acrylic copolymer resin for toner (glass transition temperature (Tg) = 58 ° C., flow softening temperature (T1 / 2) = 155 ° C.)

<Colorant>
Colorant: Carbon black (Mitsubishi Chemical Corporation, # 44)

<Charge control agent>
CCA (1): salicylic acid zirconium salt (Hodogaya Chemical Co., Ltd., trade name: TN-105)
CCA (2): Salicylic acid zinc salt (made by Orient Chemical Co., Ltd., trade name: BONTORON E-304)

<Release agent>
WAX (1): Carnauba wax (manufactured by Hiroyuki Kato, trade name: Carnauba wax No. 1 powder)
WAX (2): Polypropylene wax (manufactured by Sanyo Chemical Co., Ltd., trade name: Viscol 550P)
<Inorganic filler>
Inorganic filler (1): Kaolin clay (manufactured by BASF, trade name ASP-200)
Inorganic filler (2): Heavy calcium carbonate (Bihoku Powder Chemical Co., Ltd., Softon 3200)

[Toner Evaluation Method]
[Glass-transition temperature]
The glass transition temperature of the toner was measured using a DSC system (differential scanning calorimeter) (“DSC-60”, manufactured by Shimadzu Corporation). The sample was heated to 150 ° C. at a temperature increase rate of 10 ° C./min, then cooled from 150 ° C. to 30 ° C. at a temperature decrease rate of 10 ° C./min, and then further heated to 150 ° C. at a temperature increase rate of 10 ° C./min. And it calculated | required from the shoulder peak resulting from the glass transition of the DSC curve at the time of the 2nd temperature rise.

[Surface ratio of inorganic filler]
The surface presence of the inorganic filler was observed from an electron microscope image. Moreover, the surface presence rate of the inorganic filler was calculated | required from the infrared absorption spectrum intensity | strength resulting from an inorganic filler by calculation. The infrared absorption spectrum intensity was measured at an incident angle of 60 degrees using a Perkin Elmer FT-IR Spectrum-1 equipped with a variable angle ATR accessory. First, 0.1, 1.0, 5.0, and 10.0 parts by weight of an inorganic filler are previously attached to the toner surface with respect to 100 parts by weight of the toner, and the infrared absorption spectrum intensity with respect to the surface abundance of the inorganic filler is determined. Calculated. In the case of kaolin clay, the infrared absorption spectrum intensity in the vicinity of the wavelength 914 (cm ⁻¹ ) is calculated. Next, the infrared absorption spectrum intensity resulting from the inorganic filler of the toner of the present invention was determined, and the surface abundance of the inorganic filler was determined from the relationship between the surface abundance of the known inorganic filler and the infrared absorption spectrum intensity. Next, the surface abundance (%) of the inorganic filler was determined by calculation from the ratio between the content of the inorganic filler and the surface abundance of the inorganic filler.

[Charge amount]
A developer composed of 4% by mass of toner and 96% by mass of copper-zinc ferrite particles coated with a silicone resin and having an average particle diameter of 50 μm was prepared. Next, 6 g of developer was weighed and charged into a metal cylinder that could be sealed, and the charge amount was determined by the blow-off method. In addition, the range of −10 to 30 μC / g is appropriate for the charge amount. If the absolute value of the charge amount is less than 10 μC / g, background stains and toner scattering tend to occur, and if it exceeds 40 μC / g, the image density decreases.

[Low temperature fixability]
Ricoh's T6200 copy printing paper is used in the fixing test machine consisting of the fixing part of RICOH Co., Ltd. MF-4550 using a polytetrafluoroethylene roller as the fixing roller. The fixing lower limit temperature at which fixing can be performed stably was confirmed at intervals of 5 ° C., and the low-temperature fixing property was evaluated. The mechanical conditions were a paper feed linear velocity of 140 mm / sec, a surface pressure of 1.2 kgf / cm ² , and a nip width of 3 mm.
The evaluation was made as ◯ if the fixing lower limit temperature was 140 ° C. or lower, Δ if it was in the range of 140 ° C. to 150 ° C., and X if it was 150 ° C. or higher.

[Preservation]
The toner was stored at 50 ° C. for 8 hours and then sieved with a 42 mesh sieve for 2 minutes, and the residual rate on the wire mesh was measured. In addition, the heat resistant storage stability was determined as ◯ when the remaining rate was less than 10%, Δ when the remaining rate was 10% or more and less than 30%, and × when the remaining rate was 30% or more.

[Image evaluation]
Using imagio Neo 450 (manufactured by Ricoh), 5000 sheets were continuously printed at a printing speed of 33 sheets / minute and a printing density of 6% using A4 size paper. After printing, the following evaluation was performed.

[Cover]
The blank image is stopped during development, the developer on the developed photoreceptor is tape transferred, and the difference from the image density of the untransferred tape is measured using a 938 spectrocytometer (manufactured by X-Rite). It was measured. In the evaluation, the case where the difference was less than 0.010 was evaluated as ◯, the case where 0.010 or more and less than 0.030 was evaluated as Δ, and the case where it was 0.030 or more was determined as ×.

[Image density]
After outputting a solid black image, the image density was measured using a 938 spectrodensitometer (manufactured by X-Rite). In the evaluation, a case where the image density was 1.40 or more was evaluated as ◯, a case where the image density was 1.20 or more and less than 1.40 was determined as Δ, and a case where the image density was less than 1.20 was determined as ×.

[Comprehensive evaluation]
In the low-temperature fixability, storage stability, and image evaluation, comprehensive evaluation was performed according to the following criteria.
The overall evaluation was determined as ◯ if Δ was within two, Δ if there were three or more Δ, and X if there was at least one X.

[Example 1]
Hereinafter, a toner production example and evaluation results of the produced toner will be specifically described. As raw materials of the toner, as shown in Table 1, the binder resin (1) and the binder resin (2), the colorant, the charge control agent (1), and the release agent (1). And the said inorganic filler (1) was used in the ratio shown in Table 1. Each raw material was weighed so as to have a total of 5 kg at the ratio shown in Table 1, and then mixed for 3 minutes with a high-speed mixer to obtain a mixture of raw materials. Next, the obtained mixture of raw materials was melt-kneaded at a temperature of 120 ° C., a discharge rate of 10 Kg / hour, and a rotational speed of 150 rpm using a closed continuous kneading extruder (L / D = 30). A 2 mm plate-like melt-kneaded product was obtained.
Subsequently, the melt-kneaded product was pulverized with a mechanical pulverizer and then classified with an airflow classifier to obtain toner base particles having a volume average particle diameter of 9.5 μm. Next, 1.0 part by weight of hydrophobic silica (R974, manufactured by Nippon Aerosil Co., Ltd.) is added to 100 parts by weight of the obtained toner base particles, and 3 times at a peripheral speed of 40 m / sec using a high speed mixer. The mixture was stirred and mixed for minutes to obtain toners of Examples 1 to 5 and Comparative Examples 1 to 4. The toner physical properties and image characteristics of the obtained toner were evaluated, and the results are summarized in Table 1.

[Example 2]
The same as in Example 1 except that the binder resin, colorant, charge control agent, release agent, and inorganic filler shown in Table 1 were used as raw materials for the toner in the proportions shown in Table 1. Thus, the toner of Example 2 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
The same as in Example 1 except that the binder resin, colorant, charge control agent, release agent, and inorganic filler shown in Table 1 were used as raw materials for the toner in the proportions shown in Table 1. Thus, the toner of Example 3 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
The same as in Example 1 except that the binder resin, colorant, charge control agent, release agent, and inorganic filler shown in Table 1 were used as raw materials for the toner in the proportions shown in Table 1. Thus, the toner of Example 4 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 5]
The same as in Example 1 except that the binder resin, colorant, charge control agent, release agent, and inorganic filler shown in Table 1 were used as raw materials for the toner in the proportions shown in Table 1. Thus, the toner of Example 5 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
The same as in Example 1 except that the binder resin, the colorant, the charge control agent, the release agent, and the inorganic filler shown in Table 2 were used as raw materials for the toner in the proportions shown in Table 2. Thus, the toner of Comparative Example 1 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 2]
As the toner raw materials, the binder resin, colorant, charge control agent, and release agent shown in Table 2 were used in the proportions shown in Table 2 (in Comparative Example 1, no inorganic filler was used). The toner of Comparative Example 2 was obtained in the same manner as in Example 1, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 3]
The same as in Example 1 except that the binder resin, the colorant, the charge control agent, the release agent, and the inorganic filler shown in Table 2 were used as raw materials for the toner in the proportions shown in Table 2. Thus, the toner of Comparative Example 3 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 4]
The same as in Example 1 except that the binder resin, the colorant, the charge control agent, the release agent, and the inorganic filler shown in Table 2 were used as raw materials for the toner in the proportions shown in Table 2. Thus, the toner of Comparative Example 4 was obtained, and the toner physical properties and image characteristics of this toner were evaluated in the same manner as in Example 1. The results are shown in Table 2.

  As is clear from Table 1, the toners of Examples 1 to 4 are excellent in low-temperature fixability and storage stability, and also excellent in image quality. On the other hand, since the toner of Comparative Example 1 in Table 2 did not contain an inorganic filler, the low-temperature fixability was excellent, but the storage stability was deteriorated. In the toner of Comparative Example 2, since 20 parts by weight of the inorganic filler was added, the low-temperature fixability deteriorated, the toner charge amount decreased, and the image quality such as fogging deteriorated. Since the toner of Comparative Example 3 had a glass transition temperature of 60 ° C., the storage stability was good, but the low-temperature fixability deteriorated. Further, since the toner of Comparative Example 4 has a glass transition temperature of 48 ° C., the low-temperature fixability is good, but the storage stability is deteriorated.

JP-A-63-139364 JP 2004-361663 A JP 2007-011347 A

Claims (10)

An electrostatic charge image developing toner obtained from a toner material comprising at least a binder resin, a colorant, and one or more inorganic fillers selected from calcium carbonate, kaolin clay, talc, and barium sulfate. The glass transition temperature is in the range of 54 to 58 ° C., and the content of the inorganic filler is 1 to 10 parts by weight with respect to 100 parts by weight of the toner, and a part of the inorganic filler is present on the surface of the toner base particles. A toner for developing an electrostatic charge image, wherein the ratio of the inorganic filler present on the surface of the toner base particles is in the range of 5 to 40% with respect to the content of the inorganic filler.   The electrostatic image developing toner according to claim 1, wherein the inorganic filler has a number average particle diameter of 0.1 to 10 μm.   3. The electrostatic charge image development according to claim 1, wherein the inorganic filler is surface-treated with one or more kinds of treatment agents selected from silane coupling agents, surfactants, and metal soaps. Toner.   4. The electrostatic charge image developing toner according to claim 1, wherein the binder resin includes a binder resin having a glass transition temperature of 48 ° C. to 55 ° C. 5.   The electrostatic image developing toner according to claim 1, wherein the binder resin contains a polyester resin. A toner material containing at least a binder resin, a colorant, and at least one inorganic filler selected from calcium carbonate, kaolin clay, talc, and barium sulfate is melt-kneaded, and the resulting melt-kneaded product is pulverized and classified. A method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 5. How binder resin, containing a binder resin contained in the granulated toner base particles in an aqueous medium, to produce a toner for electrostatic image development according to claim 6.   6. A one-component developer for an electrostatic charge image comprising toner base particles of the toner for developing an electrostatic charge image according to claim 1 and an external additive.   6. A two-component developer for an electrostatic charge image, comprising toner base particles and carrier particles of the toner for developing an electrostatic charge image according to any one of claims 1 to 5. An image forming apparatus comprising: a developing unit storing the developer according to claim 8.