JP6403493B2 - Negatively chargeable toner - Google Patents

Description

  The present invention relates to an electrophotographic image forming method for developing an electrostatic charge image, and a toner used in a toner jet.

In recent years, image forming apparatuses such as copiers and printers have been required to have higher image quality as the purpose of use and environment of use have diversified. For example, copiers that were conventionally used in offices are now used in harsh environments, and it is important to provide stable image quality even in such cases. It has become.
In copiers and printers, downsizing and energy saving of devices are progressing, and a one-component developing system advantageous in these respects is preferably used.
For example, in the magnetic one-component development system, a magnetic carrier is coated on a developing sleeve using a toner carrier (hereinafter referred to as a developing sleeve) provided with a magnetic field generating means such as a magnet roll, and is conveyed and developed. Further, the charge application to the magnetic toner is performed mainly by frictional charging by rubbing between the magnetic toner and a frictional charge applying member such as a developing sleeve.

In order to achieve higher image quality, a toner having a high charge amount is required as the toner. If toner having a high charge amount is used, the electrostatic latent image can be developed faithfully. However, when the charge amount of the toner is increased in the one-component development method, the electrostatic repulsion force between the toners on the developing sleeve increases, causing a toner coat defect and an image defect.
Therefore, in order to achieve high image quality with the one-component development system, the toner charge amount on the developing sleeve is kept low to suppress toner coating defects, and the charge amount increases when developing an electrostatic latent image. There has been a demand for a toner capable of neatly developing an electrostatic latent image.

As one of the methods, for example, Patent Document 1 discloses a method of externally adding hydrotalcite, which is a positively chargeable inorganic fine powder, to a negatively chargeable toner. By adding hydrotalcite to negatively chargeable toner, frictional charging occurs between the toner and hydrotalcite, and the effect of improving the charge amount of the toner is shown. However, in order for the positively chargeable inorganic fine powder to improve the charge amount of the toner, it is necessary to peel off after rubbing with the toner. Hydrotalcite tends to behave with the toner, and the adhesion between the toner and the hydrotalcite tends to be high, especially after long-term use in a high temperature and high humidity environment. When hydrotalcite does not peel from the toner, the effect of improving the charge amount during development is small, and furthermore, since the toner is a mixture of positive chargeability and negative chargeability, the electrostatic latent image can be developed faithfully. In some cases, image density unevenness, fogging, and roughness may deteriorate, and further improvement is necessary.
Patent Document 2 discloses a toner externally added with magnetic powder having a charge amount of +1 to +15 μC / g. As an effect of externally adding the magnetic powder surface-treated with the isostearoyl group-containing titanate coupling agent, the magnetic powder does not detach from the toner, and the effect of improving the image density unevenness is shown by acting together with the toner. Since the isostearoyl group is a hydrocarbon having 18 carbon atoms, the toner has high affinity with the binder resin, and the magnetic powder adheres to the toner and behaves. In such a toner externally added with magnetic powder, the positively chargeable magnetic powder is not peeled off from the toner, so that the toner charge amount is reduced and image density unevenness may be worsened. Further, when the positively chargeable magnetic powder does not peel off, the toner becomes a mixture of positively chargeable and negatively chargeable properties, so that fogging, scattering and roughness may be deteriorated, and further improvement is necessary.

Japanese Patent No. 5268452 Japanese Patent Laid-Open No. 11-84714

  An object of the present invention is to provide a negatively chargeable toner capable of solving the above problems. Specifically, on the developing sleeve, the charge amount is kept low to stabilize the toner coat, and the charge amount is increased during development, so that the image density unevenness is good, and fog and dust are good while suppressing fogging. It is to provide a negatively chargeable toner.

The present invention is a toner containing toner particles containing a binder resin, and magnetic iron oxide particles externally added to the toner particles, the magnetic iron oxide particles having an Al element on the surface ,
The amount of the magnetic iron oxide particles externally added to the toner particles is 1.0 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles;
Number average particle diameter of magnetic iron oxide particles are negatively chargeable toner according to claim der Rukoto least 0.19μm below 0.10 .mu.m.

  According to the present invention, magnetic iron oxide particles having an Al element on the surface have an effect of imparting charge to the toner by peeling from the toner during development. Therefore, it is possible to stabilize the coating on the developing sleeve by keeping the charging amount on the developing sleeve low, and to dramatically improve the charging amount of the toner on the electrostatic latent image carrier. It became possible to develop the image faithfully. As a result, it is possible to provide a negatively chargeable toner that is excellent in scattering and roughness while suppressing image density unevenness and fogging.

Hereinafter, the present invention will be described in detail.
The present invention relates to a toner containing toner particles containing a binder resin and magnetic iron oxide particles externally added to the toner particles, wherein the magnetic iron oxide particles have an Al element on the surface. The present invention relates to a characteristic negatively chargeable toner.
According to the study by the present inventors, by using the negatively chargeable toner as described above, the charge amount is kept low on the developing sleeve to stabilize the toner coat, and the magnetic iron oxide particles are separated from the toner during development. By peeling off, the charge amount of the toner can be improved, and an image with good scattering and roughness can be obtained while suppressing fogging.
Note that “the Al element is present on the surface of the magnetic iron oxide particles” means that the dissolution amount (Wa) of the Al element on the surface of the magnetic iron oxide particles when dissolved with an acid is greater than 0, which will be described later. .

In order to obtain the effect of the present invention, it is necessary that Al element is present on the surface of the magnetic iron oxide particles externally added to the toner particles. The presence of the Al element increases the effect of the magnetic iron oxide particles imparting a charge to the toner, resulting in a negatively chargeable toner having a high charge amount on the electrostatic latent image carrier. In order to impart a negative charge to the toner, the magnetic iron oxide particles have a positive chargeability. When the magnetic iron oxide particles having positive charging properties are attached to the toner, the charge amount as the toner is reduced, so that the electrostatic repulsive force between the toners is suppressed on the developing sleeve, and the toner coat layer is stable. Can be formed.
On the other hand, at the time of development, the negatively chargeable toner is developed on the electrostatic latent image carrier by the force received from the development bias. At this time, the magnetic iron oxide particles having positive charging properties are subjected to a developing bias force in a direction opposite to that of the toner, and thus are separated from the toner between the developing sleeve and the electrostatic latent image carrier. As a result, it is considered that the toner to be developed on the electrostatic latent image carrier has dramatically improved the charge amount and can faithfully develop the electrostatic latent image.

Since the magnetic iron oxide particles peeled from the toner have a positive charging property, they fly to the non-image portion and are not transferred to the transfer material but consumed to the cleaning portion.
In the effect of the present invention, it is important that the magnetic iron oxide particles are separated from the toner when the toner is developed. It is considered that the charge amount of the toner is remarkably improved by the peeling charging. Even conventional externally-charged external additives receive a force from the developing bias in the direction opposite to that of the toner, but whether or not to peel from the toner depends on the adhesion force between the toner and the external additive (Coulomb force and non-static). It was determined by the electric adhesion force) and the force received from the development bias. However, since the external additive in the present invention is magnetic iron oxide particles, when the toner is developed on the electrostatic latent image carrier, the magnetic iron oxide particles are forced in the opposite direction to the toner by the magnetic force of the developing sleeve. As a result, it is considered that the peeling force is improved as compared with the external additive having no magnetism, and as a result, an excellent effect which has not been obtained conventionally is obtained.

The Al element present on the surface of the magnetic iron oxide particles is preferably present as an oxide or hydroxide from the viewpoint of the effect of imparting charge to the toner. As oxides, alumina (Al ₂ O ₃ ), hydrates thereof (for example, boehmite and diaspore which are monohydrates), or composite oxides with other metals may be combined. Examples of the composite oxide of Al include aluminum silicate which is a composite oxide with Si, and strontium aluminate which is a composite oxide with Sr. On the other hand, examples of the hydroxide include Al (OH) ₃ .

Magnetic iron oxide particles used as an external additive in the present invention are magnetic iron oxides such as magnetite, maghemite, and ferrite, or magnetic iron oxides containing other metal oxides; metals such as Fe, Co, Ni, or , Alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V, or these Can be used.
The amount of the magnetic iron oxide particles externally added to the toner particles is preferably 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles from the viewpoint of controlling the chargeability of the toner. More preferably, it is 0.05 parts by mass or more and 5 parts by mass or less. Containing 0.01 parts by mass or more contributes to improvement in the charge amount of the toner, so that the image density unevenness is improved. Further, by containing 10 parts by mass or less, it becomes possible to keep the charge amount of the toner in a high state, and image density unevenness is improved.

The method for producing magnetic iron oxide particles used in the present invention is not particularly problematic even if a general production method is used, but a particularly preferred production method will be specifically described below.
As a method for producing magnetic iron oxide particles used in the present invention, ferrous hydroxide slurry obtained by neutralizing and mixing a ferrous salt aqueous solution and an alkaline solution is oxidized to produce magnetic iron oxide particles. Is preferred.
What can be utilized as a ferrous salt will not be specifically limited if it is water-soluble salt like ferrous sulfate or ferrous chloride. Further, a water-soluble silicate (for example, sodium silicate) may be added to the ferrous salt and mixed.
Next, the obtained ferrous salt aqueous solution and the alkali solution are neutralized and mixed to produce a ferrous hydroxide slurry.

Here, an alkali hydroxide aqueous solution such as sodium hydroxide or potassium hydroxide aqueous solution can be used as the alkaline solution.
What is necessary is just to adjust the amount of alkali solutions at the time of producing | generating a ferrous hydroxide slurry according to the shape of the magnetic iron oxide particle to obtain | require. Specifically, spherical particles can be obtained by adjusting the pH of the ferrous hydroxide slurry to be less than 8.0, and by adjusting the pH to be not less than 8.0 and not more than 9.5, a hexahedral shape is obtained. If particles are obtained and adjusted so that the pH exceeds 9.5, octahedral particles can be obtained.
In order to obtain magnetic iron oxide particles from the ferrous hydroxide slurry thus obtained, an oxidation reaction is performed by blowing an oxygen-containing gas, preferably air, into the slurry by a conventional method.

Next, an aqueous aluminum sulfate solution is added to the obtained slurry of magnetic iron oxide particles that are core particles, the pH is adjusted to 5 or more and 9 or less, and a magnetic oxidation in which a coating layer containing an Al element is formed on the surface of the particles A slurry of iron particles is obtained. At this time, when the aluminum sulfate aqueous solution is added, an aqueous solution containing another element such as a sodium silicate aqueous solution may be simultaneously added.
The obtained magnetic iron oxide particle slurry forming the surface coating layer is filtered, washed, dried, and pulverized by conventional methods to obtain magnetic iron oxide particles.
The amount of Al element present on the surface of the magnetic iron oxide particles is preferably 0.05% by mass or more and 10% by mass or less from the viewpoint of controlling the chargeability of the toner, more preferably 0.1% by mass or more. 5% by mass or less. In the present invention, the amount of Al element present on the surface of the magnetic iron oxide particles refers to the mass% of the Al element on the surface of the magnetic iron oxide particles relative to the Fe element of the entire magnetic iron oxide particles. When the Al element is 0.05% by mass or more, the effect of imparting charge to the toner is enhanced, and the scattering is improved. Further, when the content is 10% by mass or less, the toner and the magnetic iron oxide particles are effectively separated, so that the effect of imparting charge to the toner is enhanced and the scattering is improved.
The amount of Al element present on the surface of the magnetic iron oxide particles can be controlled by adjusting the amount of the aluminum sulfate solution used when forming the Al element coating layer on the surface of the magnetic iron oxide particles. .

The number average particle diameter of the magnetic iron oxide particles is 0.05 μm or more and 1.0 μm or less, and the effect that the magnetic iron oxide particles impart to the toner and the magnetic iron oxide particles are easily separated from the toner during development. From the viewpoint, it is preferably 0.05 μm or more and 0.5 μm or less, and more preferably 0.05 μm or more and 0.19 μm or less.
The number average particle diameter of the magnetic iron oxide particles is determined from the reaction temperature, the stirring speed, the concentration of the ferrous hydroxide slurry, and the water solubility when performing an oxidation reaction to obtain magnetic iron oxide particles from the ferrous hydroxide slurry. It can be controlled by adjusting the concentration of additives such as silicate silicate.

The number average particle diameter of the magnetic iron oxide particles is measured as follows.
The number average particle diameter of the magnetic iron oxide particles is measured by “Scanning Electron Microscope S-4800” (manufactured by Hitachi High-Technologies Corporation). The number average particle size of the magnetic iron oxide particles is determined by measuring the length of the two sides of the magnetic iron oxide particles from an electron micrograph, and taking the average of the lengths of the two sides as the particle size. Calculated as the arithmetic mean of diameter.

In the magnetic iron oxide particles, the ratio (Wb / Wa) between the dissolution amount Wa of the surface Al element when dissolved with an acid and the dissolution amount Wb of the surface Al element when dissolved with an alkali is the effect of imparting toner charge. In view of the above, it is preferably 0.60 or less, and more preferably 0.56 or less.
The dissolution amount Wa of the surface Al element when dissolved with an acid indicates the amount of all Al elements present on the surface. This is because the magnetic iron oxide particles are soluble in acid, and the Al element on the surface is dissolved together with the core particles. On the other hand, the dissolution amount Wb of the surface Al element when dissolved with an alkali is a value affected by the presence state of Al. Since magnetic iron oxide particles are insoluble in alkali, only Al in a state dissolved in alkali is detected among Al elements present on the surface. For example, aluminum hydroxide or aluminum silicate, which is a composite oxide of Al and Si, is detected because it is soluble in alkali, but alumina (Al ₂ O ₃ ), which is an oxide of Al, is detected because it is insoluble in alkali. Not.
The fact that Wb / Wa is 0.60 or less indicates that 40% or more of Al elements existing on the surface are present in an insoluble and stable state in an alkali such as alumina. The presence of the Al element on the surface of the magnetic iron oxide particles in a stable state is considered to provide a stable charge imparting effect to the toner, improve the roughness, and obtain a high-quality image.
The lower limit of Wb / Wa is not particularly limited, but is preferably 0.10 or more.
Note that the value of Wb / Wa can be controlled by the addition rate, the concentration of the aluminum sulfate aqueous solution, the reaction temperature, and the like when the aqueous aluminum sulfate solution is added to the slurry of magnetic iron oxide particles that are core particles.

The method for measuring the Al element on the surface of the magnetic iron oxide particles is as follows.
(1) Method of measuring the amount of dissolved Al element (Wa) on the surface of magnetic iron oxide particles when dissolved in acid The amount of dissolved Al element (Wa) on the surface of magnetic iron oxide particles when dissolved in acid is It can be determined by a method. 3 g of magnetic iron oxide particles are suspended in 300 ml of 3N hydrochloric acid solution. Next, a magnetic iron oxide particle suspension hydrochloric acid solution is kept at 50 ° C., and sampling is performed at regular intervals until all the magnetic iron oxide particles are dissolved, and this is filtered through a membrane filter to obtain a filtrate. The filtrate is subjected to quantitative determination of Fe element and Al element with an induction plasma atomic emission spectrophotometer. The Fe element dissolution rate and the Al element dissolution rate are calculated by the following equations.
Fe element dissolution rate (%) = Fe element concentration in the sample (mg / l) / Fe element concentration when completely dissolved (mg / l) × 100
Al element dissolution rate (%) = Al element concentration in the sample (mg / l) / Al element concentration when completely dissolved (mg / l) × 100
Measure the Al element dissolution rate when the Fe element dissolution rate is 1%, 5%, and 10%, and perform a linear approximation using the three points to calculate the Al element dissolution rate when the Fe element dissolution rate is 0%. The dissolution amount (Wa) (mg / l) of Al element on the surface of the magnetic iron oxide particles when dissolved with acid. In addition, since the dissolution amount (Wa) of the surface Al element when dissolved with an acid indicates the amount of all Al elements present on the surface, Wa (mg / l) / completely dissolved from the Wa. The amount (mass%) of the Al element present on the surface of the magnetic iron oxide particles is calculated from the Fe element concentration (mg / l) × 100.

(2) Measuring method of dissolution amount (Wb) of Al element on the surface of magnetic iron oxide particles when dissolved with alkali The dissolution amount (Wb) of Al element on the surface of magnetic iron oxide particles when dissolved with alkali is as follows: Measure as follows. First, 3 g of magnetic iron oxide particles are suspended in 300 ml of 3N aqueous sodium hydroxide solution. After stirring at 50 ° C. for 30 minutes or more, the suspension is filtered through a membrane filter to obtain a filtrate. The filtrate is subjected to quantitative determination of Fe element and Al element with an induction plasma atomic emission spectrophotometer, and the dissolution amount (Wb) (mg / l) of Al element is calculated.

Examples of the binder resin used in the toner of the present invention include the following. Vinyl resin, styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, Silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin. Among these, styrene copolymer resins, polyester resins, hybrid resins in which a polyester resin and a vinyl resin are mixed, or partially reacted are listed as preferred resins.
The component which comprises the said polyester resin is explained in full detail. In addition, the following components can use 1 type, or 2 or more types according to a kind and a use.

Examples of the divalent acid component constituting the polyester resin include the following dicarboxylic acids or derivatives thereof. Benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, or anhydrides thereof, or lower alkyl esters thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, or anhydrides thereof; Its lower alkyl ester; C1-C50 alkenyl succinic acid or alkyl succinic acid, or its anhydride or its lower alkyl ester; Unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, itaconic acid or its anhydrous Or a lower alkyl ester thereof.
On the other hand, the following are mentioned as a bivalent alcohol component which comprises a polyester resin. Ethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5 -Pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenation Bisphenol A, bisphenol represented by formula (1) and derivatives thereof: and diols represented by formula (2).

（式中、Ｒはエチレン又はプロピレン基であり、ｘ、ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０乃至１０である。）

(In the formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)

The constituent component of the polyester resin used in the present invention contains a trivalent or higher carboxylic acid compound and a trivalent or higher alcohol compound as a constituent component in addition to the above divalent carboxylic acid compound and divalent alcohol compound. May be.
Although it does not restrict | limit especially as a trivalent or more carboxylic acid compound, Trimellitic acid, trimellitic anhydride, pyromellitic acid, etc. are mentioned. Examples of the trihydric or higher alcohol compound include trimethylolpropane, pentaerythritol, and glycerin.
In the present invention, the method for producing the polyester resin is not particularly limited, and a known method can be used. For example, the above-described divalent carboxylic acid compound and divalent alcohol compound are polymerized through an esterification reaction or a transesterification reaction and a condensation reaction to produce a polyester resin. The polymerization temperature is not particularly limited, but a range of 180 ° C. or higher and 290 ° C. or lower is preferable. In the polymerization of the polyester resin, for example, a polymerization catalyst such as a titanium-based catalyst, a tin-based catalyst, zinc acetate, antimony trioxide, and germanium dioxide can be used.

In the present invention, it is preferable that at least styrene is used as the vinyl monomer for producing the vinyl resin. Since styrene has a large proportion of aromatic rings in the molecular structure, durability stability is more advantageous.
Examples of the vinyl monomer for producing a vinyl copolymer unit other than styrene include the following styrene monomers and acrylic acid monomers.
Styrene monomers include o-methyl styrene, m-methyl styrene, p-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert-butyl. Styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chloro styrene, 3,4 -Styrene derivatives such as dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene.

  Examples of acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, acrylate-n-butyl, acrylate isobutyl, acrylate-n-octyl, dodecyl acrylate, and 2-ethylhexyl acrylate. , Acrylic acid and acrylic esters such as stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid-n-butyl, methacrylic acid Such as isobutyl, methacrylate-n-octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate - methylene aliphatic monocarboxylic acids and their esters; acrylonitrile, methacrylonitrile, acrylic acid or methacrylic acid derivatives such as acrylamide.

  Furthermore, as a monomer constituting the vinyl resin, acrylic acid or methacrylic acid esters such as 2-hydroxylethyl acrylate, 2-hydroxylethyl methacrylate, 2-hydroxylpropyl methacrylate, 4- (1-hydroxy-1-methylbutyl) Examples thereof include monomers having a hydroxyl group such as styrene and 4- (1-hydroxy-1-methylhexyl) styrene.

  Various monomers capable of vinyl polymerization can be used in combination with the vinyl resin as necessary. Examples of such monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride. Vinyl halides such as; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether: vinyl vinyl ketone, vinyl hexyl ketone, Vinyl ketones such as methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; further maleic acid, citraconic acid Unsaturated dibasic acids such as itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; unsaturated dibasic acid anhydrides such as maleic acid anhydride, citraconic acid anhydride, itaconic acid anhydride, alkenyl succinic acid anhydride Products: maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, alkenyl succinic acid methyl half ester Unsaturated basic acid half ester such as methyl fumarate half ester and methyl mesaconic acid half ester; Unsaturated basic acid ester such as dimethylmaleic acid and dimethyl fumaric acid; Acrylic acid, methacrylic acid, crotonic acid, citron Α, β-unsaturated acid anhydrides such as: anhydrides of the α, β-unsaturated acids and lower fatty acids; alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, their acid anhydrides and these And a monomer having a carboxyl group such as a monoester.

Further, the vinyl resin may be a polymer crosslinked with a crosslinkable monomer as exemplified below if necessary. Crosslinkable monomers include, for example, aromatic divinyl compounds, diacrylate compounds linked by alkyl chains, diacrylate compounds linked by alkyl chains containing ether bonds, and chains containing aromatic groups and ether bonds. And diacrylate compounds, polyester-type diacrylates, and polyfunctional crosslinking agents.
Examples of the aromatic divinyl compound include divinylbenzene and divinylnaphthalene.

Examples of diacrylate compounds linked by the alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1, Examples include 6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate.
Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, Examples include dipropylene glycol diacrylate and those obtained by replacing acrylate of the above compound with methacrylate.

Examples of the diacrylate compounds connected by a chain containing an aromatic group and an ether bond include polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4 ) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate.
Examples of polyester diacrylates include trade name MANDA (Nippon Kayaku).
Examples of the polyfunctional crosslinking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing acrylates of the above compounds with methacrylate. Triallyl cyanurate, triallyl trimellitate; and the like.

The vinyl resin may be a resin produced using a polymerization initiator. These polymerization initiators are preferably used in an amount of 0.05 to 10 parts by mass with respect to 100 parts by mass of the monomer from the viewpoint of efficiency.
Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis ( 2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1,1′-azobis (1-cyclohexanecarbonitrile) 2-carbamoylazoisobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2′-azobis Ketone peroxides such as (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, 2 2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butyl Cumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethyl Hexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxye Ruperoxycarbonate, dimethoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t- Butyl peroxyneodecanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl Peroxyisophthalate, t-butylperoxyallyl carbonate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate And the like.

As described above, the hybrid resin is a resin in which a polyester resin and a vinyl resin are mixed or partially reacted.
Therefore, it is preferable to carry out the polymerization using a compound capable of reacting with both monomers of the resin (hereinafter referred to as “both reactive compounds”). Examples of such a bireactive compound include compounds such as fumaric acid, acrylic acid, methacrylic acid, citraconic acid, maleic acid, and dimethyl fumarate in the monomer of the polyester resin and the monomer of the vinyl resin. Of these, fumaric acid, acrylic acid, and methacrylic acid are preferably used.

As a method for obtaining a hybrid resin, it can be obtained by reacting a raw material monomer of a polyester resin and a raw material monomer of a vinyl resin simultaneously or sequentially. For example, when a raw material monomer of a polyester resin is subjected to a condensation polymerization reaction after an addition polymerization reaction of a vinyl copolymer monomer, it is easy to control the molecular weight.
In the hybrid resin, the mixing ratio (mass ratio) of the polyester resin and the vinyl resin is preferably 50/50 to 90/10 for the polyester resin / vinyl resin from the viewpoint of controlling the cross-linked structure at the molecular level. / 50-80 / 20 is more preferable.

The binder resin of the present invention may contain two or more binder resins.
When two or more binder resins are contained, it is preferable to use a high softening point resin and a low softening point resin. The high softening point resin preferably has a softening point of 120 ° C or higher and 170 ° C or lower. Further, the low softening point resin preferably has a softening point of 70 ° C or higher and lower than 120 ° C.
By including two or more kinds of binder resins having different softening points, the molecular weight distribution of the toner can be designed relatively easily and a wide fixing area can be provided.
When one kind of binder resin is used alone, the softening point is preferably 95 ° C or higher and 170 ° C or lower. More preferably, it is 120 degreeC or more and 160 degrees C or less. When Tm is within the above range, high-temperature offset resistance and low-temperature fixability are good.

The softening point is measured as follows. The softening point of the resin is measured by using a constant load extrusion type capillary rheometer “flow characteristic evaluation device Flow Tester CFT-500D” (manufactured by Shimadzu Corporation) according to the manual attached to the device. In this device, while applying a constant load from the top of the measurement sample with the piston, the measurement sample filled in the cylinder is heated and melted, and the melted measurement sample is pushed out from the die at the bottom of the cylinder, and the piston drop amount at this time A flow curve showing the relationship between temperature and temperature can be obtained.
In the present invention, the “melting temperature in the 1/2 method” described in the manual attached to the “flow characteristic evaluation apparatus Flow Tester CFT-500D” is the softening point. The melting temperature in the 1/2 method is calculated as follows. First, ½ of the difference between the piston lowering amount Smax at the time when the outflow ends and the piston lowering amount Smin at the time when the outflow starts is obtained (this is X. X = (Smax−Smin) / 2). And the temperature of the flow curve when the amount of piston descent in the flow curve is the sum of X and Smin is the melting temperature Tm in the 1/2 method.

As a measurement sample, about 1.3 g of a sample is compression-molded at about 10 MPa using a tablet-molding compressor (for example, NT-100H, manufactured by NPA System) in an environment at 25 ° C. for about 60 seconds. A cylindrical shape having a diameter of about 8 mm is used.
The measurement conditions of CFT-500D are as follows.
Test mode: Temperature rising start temperature: 50 ° C
Achieving temperature: 200 ° C
Measurement interval: 1.0 ° C
Temperature increase rate: 4.0 ° C./min
Piston cross-sectional area: 1.000 cm ²
Test load (piston load): 10.0 kgf (0.9807 MPa)
Preheating time: 300 seconds Die hole diameter: 1.0 mm
Die length: 1.0mm

The glass transition temperature (Tg) of the binder resin is preferably 45 ° C. or higher from the viewpoint of storage stability. Further, from the viewpoint of low-temperature fixability, Tg is preferably 75 ° C. or less, and particularly preferably 65 ° C. or less.
The glass transition temperature (Tg) of the binder resin for toner is measured under normal temperature and humidity according to ASTM D3418-82 using a differential scanning calorimeter (DSC) and MDSC-2920 (manufactured by TA Instruments). To do. As a measurement sample, a precisely weighed about 3 mg of binder resin is used. This is put in an aluminum pan and an empty aluminum pan is used as a reference. The measurement temperature range is 30 ° C. or more and 200 ° C. or less, once the temperature is increased from 30 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min, then the temperature is decreased from 200 ° C. to 30 ° C. at a temperature decrease rate of 10 ° C./min. The temperature is raised to 200 ° C. at a temperature rising rate of 10 ° C./min. In the DSC curve obtained in the second temperature raising process, the intersection point between the baseline intermediate line before and after the specific heat change and the differential heat curve is defined as the glass transition temperature Tg of the resin.

The toner of the present invention can be used as any one of magnetic one-component toner, non-magnetic one-component toner, and non-magnetic two-component toner. Of these, the use as a magnetic one-component toner is most suitable for obtaining the effect.
When used as a magnetic one-component toner, magnetic iron oxide particles are preferably used as the colorant. Magnetic iron oxide particles contained in the magnetic one-component toner include magnetic iron oxides such as magnetite, maghemite, and ferrite, or magnetic iron oxides including other metal oxides; metals such as Fe, Co, and Ni, or Alloys of these metals with metals such as Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, V, or these A mixture is mentioned. In addition, you may use the magnetic iron oxide particle which has Al element on the surface based on this invention.

Examples of the colorant used as the nonmagnetic one-component toner and the nonmagnetic two-component toner include the following.
As the black pigment, carbon black such as furnace black, channel black, acetylene black, thermal black and lamp black is used, and magnetic powder such as magnetite and ferrite is also used.

As a colorant suitable for the yellow color, a pigment or a dye can be used. Examples of the pigment include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 13
7, 138, 139, 147, 151, 154, 155, 167, 168, 173, 174, 176, 180, 181, 183, 191, C.I. I. Examples include bat yellow 1, 3, 20 and the like. Examples of the dye include C.I. I. Solvent yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162 etc. are mentioned. These may be used alone or in combination of two or more.

  As a colorant suitable for cyan, a pigment or a dye can be used. Examples of the pigment include C.I. I. Pigment Blue 1, 7, 15, 15; 1, 15; 2, 15; 3, 15; 4, 16, 17, 60, 62, 66, etc. I. Bat Blue 6, C.I. I. Acid Blue 45 and the like. Examples of the dye include C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. are mentioned. These may be used alone or in combination of two or more.

A pigment or dye can be used as a colorant suitable for magenta. Examples of the 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, 48; 2, 48; 3, 48; 4, 49, 50, 51, 52, 53, 54, 55, 57, 57; 1, 58, 60, 63, 64, 68, 81, 81; 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, etc. I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned.
Examples of the magenta dye include C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122, etc. I. Disper thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27, etc., C.I. I. Oil-soluble dyes such as disperse violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, etc. I. Basic violet 1,3,7,10,14,15,21,25,26,27,28 etc. basic dyes etc. are mentioned. These may be used alone or in combination of two or more.

  In order to impart releasability to the toner, the toner preferably contains a release agent (wax). As the wax, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax are preferably used because of easy dispersion in the toner and high releasability. It is done. If necessary, one or two or more kinds of waxes may be used together in a small amount. Examples include the following:

Oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax and montanate wax; Deoxidized part or all of such fatty acid esters.
Furthermore, the following are mentioned. Saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and parinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; Saturated fatty acid bisamides such as ethylene biscapric acid amide, ethylene bislauric acid amide, hexamethylene bisstearic acid amide; ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleo Unsaturated fatty acid amides such as luadipic acid amide and N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylene bis-stearic acid amide and N, N-distearyl isophthalic acid amide; calcium stearate , Fatty acid metal salts such as calcium laurate, zinc stearate and magnesium stearate (generally called metal soap); grafted onto aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid A partially esterified product of a fatty acid such as behenic acid monoglyceride and a polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of vegetable oils and fats.

  Examples of waxes that are particularly preferably used in the present invention include aliphatic hydrocarbon waxes. Examples of such aliphatic hydrocarbon waxes include the following. Low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or Ziegler catalyst under low pressure; alkylene polymer obtained by thermally decomposing high molecular weight alkylene polymer; synthesis containing carbon monoxide and hydrogen Synthetic hydrocarbon waxes obtained from the distillation residue of hydrocarbons obtained from the gas by the age method and synthetic hydrocarbon waxes obtained by hydrogenating them; press sweating method, solvent method, vacuum Wax separated by use of distillation or fractional crystallization.

  Examples of the hydrocarbon as the base of the aliphatic hydrocarbon wax include the following. Carbonization synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, the Gintor method, Hydrocol method (using a fluidized catalyst bed)) Hydrogen compounds); hydrocarbons having up to several hundred carbon atoms obtained by the age method (using an identified catalyst bed) in which a large amount of waxy hydrocarbons can be obtained; hydrocarbons obtained by polymerizing alkylene such as ethylene with a Ziegler catalyst. Specific examples include the following. Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industry Co., Ltd.); High Wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals) Sazol H1, H2, C80, C105, C77 (Sazol Corporation); HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiwa Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite); wood wax, beeswax, rice wax, candelilla wax, carnauba wax (Co., Ltd.) Celerica NODA).

  When the toner is prepared by a pulverization method, the release agent may be added at the time of melt-kneading or may be at the time of production of a toner resin. These release agents may be used alone or in combination. The release agent is preferably added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  In the toner of the present invention, a known charge control agent can be used as the charge control agent. Known charge control agents include azo-based iron compounds, azo-based chromium compounds, azo-based manganese compounds, azo-based cobalt compounds, azo-based zirconium compounds, carboxylic acid derivative chromium compounds, carboxylic acid derivative zinc compounds, and carboxylic acid derivatives. And aluminum compounds of carboxylic acids and zirconium compounds of carboxylic acid derivatives. The carboxylic acid derivative is preferably an aromatic hydroxycarboxylic acid. A charge control resin can also be used. The charge control agent used in the present invention is preferably used in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

The toner of the present invention may be mixed with a carrier and used as a two-component developer. As the carrier, a normal carrier such as ferrite or magnetite or a resin-coated carrier can be used. A binder type carrier core in which magnetic powder is dispersed in a resin can also be used.
The resin-coated carrier is composed of carrier core particles and a coating material that is a resin that coats (coats) the surface of the carrier core particles. Examples of the resin used for the coating material include styrene-acrylic resins such as styrene-acrylic acid ester copolymers and styrene-methacrylic acid ester copolymers; acrylic resins such as acrylic acid ester copolymers and methacrylic acid ester copolymers. Fluorine-containing resins such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, and polyvinylidene fluoride; silicone resins; polyester resins; polyamide resins; polyvinyl butyral; aminoacrylate resins. Other examples include ionomer resins and polyphenylene sulfide resins. These resins can be used alone or in combination.

In the toner of the present invention, silica fine particles are preferably externally added to the toner particles in order to improve charging stability, developability, fluidity, and durability. The silica fine particles preferably have a specific surface area of 30 m ² / g or more and 500 m ² / g or less, more preferably 50 m ² / g or more and 400 m ² / g or less by the BET method by nitrogen adsorption. The silica fine particles are preferably used in an amount of 0.01 parts by mass or more and 8.00 parts by mass or less, and more preferably 0.10 parts by mass or more and 5.00 parts by mass or less based on 100 parts by mass of the toner particles. The BET specific surface area of the silica fine particles is, for example, a fine silica powder using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics), GEMINI 2360/2375 (manufactured by Micrometric), Tristar 3000 (manufactured by Micrometric). Nitrogen gas is adsorbed on the surface of the film, and the BET multipoint method can be used for calculation.
Silica fine particles can be made from unmodified silicone varnishes, various modified silicone varnishes, unmodified silicone oils, various modified silicone oils, silane coupling agents, and functionalized silanes for the purpose of hydrophobization and frictional charge control, as necessary. It is also preferable that the treatment is performed with a treatment agent such as a compound or other organosilicon compound, or in combination with various treatment agents.

  Furthermore, you may add another external additive to the toner of this invention as needed. Examples of such external additives include charging aids, conductivity imparting agents, fluidity imparting agents, anti-caking agents, release agents at the time of heat roller fixing, lubricants, abrasives, and the like. An inorganic fine powder is mentioned. Examples of the lubricant include polyfluorinated ethylene powder, zinc stearate powder, and polyvinylidene fluoride powder. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder. Of these, strontium titanate powder is preferable.

  As a method for producing the toner, for example, the following method can be used. The binder resin and, if necessary, the colorant, charge control agent, wax, and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. The mixture is melt kneaded using a thermal kneader such as a twin-screw kneading extruder, a heating roll, a kneader, or an extruder. At that time, wax, magnetic iron oxide particles, and a metal-containing compound may be added. The melt-kneaded product is cooled and solidified, and then pulverized and classified to obtain toner particles. Furthermore, the toner particles can be obtained by mixing the toner particles, the magnetic iron oxide particles according to the present invention, and if necessary, other external additives with a mixer such as a Henschel mixer.

The following are mentioned as a mixer. Henschel mixer (made by Mitsui Mining); Super mixer (made by Kawata); Ribocorn (made by Okawara Seisakusho); Nauta mixer, turbulizer, cyclomix (made by Hosokawa Micron); Spiral pin mixer (made by Taiheiyo Kiko) A Ladige mixer (manufactured by Matsubo).
Examples of the kneader include the following. KRC Kneader (manufactured by Kurimoto Iron Works); Bus Co Kneader (manufactured by Buss); TEM type extruder (manufactured by Toshiba Machine); TEX twin-screw kneader (manufactured by Nippon Steel); PCM kneader (Ikegai) Steel mill); three roll mill, mixing roll mill, kneader (manufactured by Inoue Seisakusho); kneedex (manufactured by Mitsui Mining); MS-type pressure kneader, nider ruder (manufactured by Moriyama Seisakusho); Banbury mixer (Kobe Steel (Made by the company).
Examples of the pulverizer include the following. Counter jet mill, micron jet, inomizer (manufactured by Hosokawa Micron); IDS type mill, PJM jet crusher (manufactured by Nippon Pneumatic Industrial Co., Ltd.); cross jet mill (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.) SK; jet mill (manufactured by Seishin Enterprise Co., Ltd.); kryptron (manufactured by Kawasaki Heavy Industries, Ltd.);

Examples of the classifier include the following. Classifier, Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise); Turbo Classifier (manufactured by Nissin Engineering); Micron Separator, Turboplex (ATP), TSP Separator (manufactured by Hosokawa Micron); Elbow Jet (Japan) Iron Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Engineering Co., Ltd.); YM Microcut (manufactured by Yaskawa Corporation).
Examples of the sieving apparatus used for sieving coarse particles include the following. Ultrasonic (manufactured by Sakae Sangyo Co., Ltd.); Resonator Sheave, Gyroshifter (Tokusu Kosakusha Co., Ltd.); Vibrasonic System (manufactured by Dalton Co.); Soniclean (manufactured by Shinto Kogyo Co., Ltd.); Micro shifter (manufactured by Hadano Sangyo Co., Ltd.); circular vibrating sieve.

Next, the method for measuring the particle size distribution of the toner according to the present invention will be described.
<Measurement of toner weight average particle diameter (D4)>
The weight average particle diameter (D4) of the toner is a precision particle size distribution measuring apparatus “Coulter Counter Multisizer by pore electrical resistance method equipped with an aperture tube of 100 μm.
3 ”(registered trademark, manufactured by Beckman Coulter) and attached dedicated software“ Beckman Coulter Multisizer 3 Version 3.51 ”(manufactured by Beckman Coulter, Inc.) for measurement condition setting and measurement data analysis, Measure with 25,000 effective measurement channels, analyze and calculate the measurement data.
As the electrolytic aqueous solution used for the measurement, special grade sodium chloride is dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
Prior to measurement and analysis, the dedicated software is set as follows.
In the “Standard Measurement Method (SOM) Change Screen” of the dedicated software, set the total count in the control mode to 50000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter, Inc.) Set the value obtained using The threshold and noise level are automatically set by pressing the threshold / noise level measurement button. Also, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the aperture tube flash after measurement is checked.
In the “pulse to particle size conversion setting screen” of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic solution is placed in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the analysis software.
(2) About 30 ml of the electrolytic aqueous solution is put in a glass 100 ml flat bottom beaker, and "Contaminone N" (nonionic surfactant, anionic surfactant, organic builder pH 7 precision measurement is used as a dispersant therein. About 0.3 ml of a diluted solution obtained by diluting a 10% by weight aqueous solution of a neutral detergent for washing a vessel (made by Wako Pure Chemical Industries, Ltd.) 3 times with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated in a state where the phase is shifted by 180 degrees, and is placed in a water tank of an ultrasonic disperser “Ultrasonic Dispersion System Tetora 150” (manufactured by Nikka Ki Bios) with an electrical output of 120 W. A predetermined amount of ion-exchanged water is put, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the (1) round bottom beaker installed in the sample stand, the (5) electrolytic aqueous solution in which the toner is dispersed is dropped using a pipette, and the measured concentration is adjusted to about 5%. Measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated. The “average diameter” on the analysis / volume statistics (arithmetic average) screen when the graph / volume% is set with the dedicated software is the weight average particle diameter (D4).

Hereinafter, the present invention will be specifically described based on examples. However, the present invention is not limited to this.
<Example of production of magnetic iron oxide particles 1>
(First reaction step)
Fe ²⁺ 1.5 mol / L containing an aqueous solution of ferrous 16L sulfate ^(Fe 2+ 24 mol) and 3
. A ferrous salt suspension prepared by mixing 15.2 L of 0N sodium hydroxide solution (corresponding to 0.95 equivalent to Fe ^2+, that is, 2OH / Fe = 0.95) and adjusting to pH 8.5. Was prepared. At this time, No. 3 water glass (SiO ₂ 28.8 mass%) was added as a silicon component so as to be 0.2 mass% in terms of Si element with respect to the Fe element. The ferrous salt suspension was aerated at a temperature of 90 ° C. with 70 L of air per minute to carry out an oxidation reaction until the ferrous salt oxidation reaction rate reached 10%. A ferrous salt suspension was obtained.

(Second reaction step)
To the ferrous salt suspension containing the magnetite nuclei particles, 3.2 L of a 3.0N sodium hydroxide solution was added (corresponding to 1.15 equivalents with respect to Fe ^2+, that is, 2OH / Fe = 1.
15) 70 L of air was aerated at a temperature of 90 ° C. to carry out the oxidation reaction until the ferrous salt oxidation reaction rate reached 50%.

(Third reaction step)
Next, an appropriate amount of 16.0 N sulfuric acid was added to the ferrous salt suspension containing the magnetite nuclei particles to adjust the pH to 7.5, and the suspension was stirred. The pH condition at this time is referred to as a relay condition. Next, an appropriate amount of 3.0N sodium hydroxide solution was added to adjust the pH to 10.5. At this time, No. 3 water glass (SiO ₂ 28.8% by mass) was added as a silicon component so as to be 0.5% by mass in terms of Si element with respect to Fe element, and at a temperature of 90 ° C., 70 L / min. Air was aerated to obtain core particles of magnetic iron oxide particles.
For the coating layer of Si and Al, No. 3 water glass was added as an Si component to the suspension containing the core particles so that the amount was 0.2% by mass in terms of Si element with respect to Fe element. A 1.9 mol / L aluminum sulfate solution as an ingredient was added to the Fe element so as to be 0.33% by mass in terms of Al element, adjusted to pH 7 and a temperature of 80 ° C. to form a coating layer, and magnetic Iron oxide particles were obtained.
The obtained magnetic iron oxide particles were filtered by a conventional method, dried and pulverized to obtain magnetic iron oxide particles 1. The magnetic iron oxide particles 1 were octahedron, the number average particle diameter was 0.12 μm, and the Al element amount was 0.30 mass%.

<Example of production of magnetic iron oxide particles 2>
For the coating layer, only the Al component was used, and the magnetic oxidation was performed in the same manner as the magnetic iron oxide particles 1 except that the temperature and air flow rate when obtaining the core particles were changed so that the number average particle diameter was 0.19 μm. Iron particles 2 were obtained. The number average particle diameter was 0.19 μm, and the Al element amount was 0.30 mass%.

<Example of production of magnetic iron oxide particles 3>
Fe ²⁺ 1.5 mol / L containing an aqueous solution of ferrous 16L sulfate ^(Fe 2+ 24 mol) and sodium hydroxide 3.0N solution 17.6L ^{(Fe 2+} to 1.10 equivalent to eq. That, 2OH / Fe = 1.10) and adjusted to pH 12.0 to prepare a ferrous salt suspension. At this time, No. 3 water glass (SiO ₂ 28.8 mass%) was added as a silicon component so as to be 0.5 mass% in terms of Si element with respect to the Fe element. This ferrous salt suspension was adjusted to a temperature of 90 ° C., and 30 L of air was aerated to carry out the oxidation reaction until the oxidation reaction rate of the ferrous salt reached 50%. Then, 20 L of air was vented per minute until the ferrous salt oxidation reaction rate reached 75%, and then 10 L of air vented until the ferrous salt oxidation reaction rate reached 90%. Further, when the oxidation reaction rate of the ferrous salt exceeded 90%, air was passed through 5 L / min to complete the oxidation reaction, and a suspension containing octahedral core particles was obtained.
To the suspension containing the core particles, No. 3 water glass as an Si component was added to the Fe element in an amount of 0.6% by mass in terms of Si element, and 1.9 mol / L as an Al component. The aluminum sulfate solution was added to Fe element so as to be 0.33% by mass in terms of Al element, adjusted to pH 7 and temperature 80 ° C. to form a coating layer, and the obtained magnetic iron oxide particles were Filtration, drying, and pulverization were performed by a conventional method to obtain magnetic iron oxide particles 3. The obtained magnetic iron oxide particles 3 were octahedral, the number average particle diameter was 0.10 μm, and the Al element amount was 0.30 mass%.

<Example of production of magnetic iron oxide particles 4>
Fe ²⁺ 1.5 mol / L containing an aqueous solution of ferrous 16L sulfate ^(Fe 2+ 24 mol) and sodium hydroxide 3.0N solution 15.2L ^{(Fe 2+} to 0.95 equivalent to eq. That, 2OH / Fe = 0.95) and adjusted to pH 8.5 to prepare a ferrous salt suspension. At this time, No. 3 water glass (SiO ₂ 28.8 mass%) was added as a silicon component so as to be 1.0 mass% in terms of Si element with respect to the Fe element. This ferrous salt suspension was adjusted to a temperature of 80 ° C., and 30 L of air was passed through every minute for an oxidation reaction to obtain a suspension containing core particles containing Si element.
To the suspension containing the core particles, No. 3 water glass as an Si component was added to the Fe element in an amount of 0.6% by mass in terms of Si element, and 1.9 mol / L as an Al component. An aluminum sulfate solution was added to Fe element so as to be 0.33% by mass in terms of Al element, adjusted to pH 10 and a temperature of 90 ° C. to form a coating layer, and the obtained magnetic iron oxide particles were Filtration, drying, and pulverization were performed by a conventional method to obtain magnetic iron oxide particles 4. The obtained magnetic iron oxide particles 3 were octahedron, the number average particle diameter was 0.50 μm, and the Al element amount was 0.30 mass%.

<Production example of magnetic iron oxide particles 6-12>
The magnetic iron oxide particles 4 except that the surface Al amount and the number average particle size were adjusted as shown in Table 1 by changing the addition amount of the aluminum sulfate solution, the temperature when obtaining the core particles, and the air flow rate. Magnetic iron oxide particles 6 to 12 were obtained by the same method.
The magnetic iron oxide particles 11 were not added with the aluminum sulfate solution in the step of forming the coating layer. The magnetic iron oxide particles 12 were filtered in the state of core particles, dried and pulverized without the step of forming a coating layer.

<Example of binder resin production>
・ Propylene oxide adduct of bisphenol A 34.0 mol% (average addition mol number: 2.2 mol)
-Ethylene oxide adduct of bisphenol A 19.5 mol% (average number of moles added: 2.2 mol)
-Isophthalic acid 23.5 mol%-n-dodecenyl succinic acid 13.5 mol%-trimellitic acid 9.5 mol%
The above monomer and dibutyltin oxide were added in an amount of 0.03 parts by mass with respect to the total acid components, and reacted with stirring at 220 ° C. for 6 hours under a nitrogen stream to obtain a polyester resin (binder resin). The softening point was 130 ° C. and Tg 62 ° C.

<Example 1>
(Production example of toner 1)
Binder resin 100 parts by mass Magnetic iron oxide particles 1 90 parts by mass Fischer-Tropsch wax 2 parts by mass Charge control agent (T-77 (manufactured by Hodogaya Chemical)) 1 part by mass After the above materials were premixed with a Henschel mixer, biaxial The mixture was melt-kneaded by a kneading extruder.
The obtained kneaded product is cooled, coarsely pulverized with a hammer mill, then pulverized with a jet mill, and the obtained finely pulverized powder is classified using a multi-division classifier utilizing the Coanda effect, and the weight average particle diameter D4) 6.8 μm negative triboelectrically chargeable toner particles were obtained. For 100 parts by mass of toner particles,
Silica fine powder (specific surface area by nitrogen adsorption measured by BET method is 140 m ² / g, hexamethyldisilazane treatment as hydrophobic treatment): 1.0 part by mass, and magnetic iron oxide particles 1: 1.0 part by mass The mixture was externally added and sieved with a mesh having an opening of 150 μm to obtain negatively chargeable toner 1.
The toner 1 was evaluated as follows. The results are shown in Table 3.

As an image forming device, Canon copier imageRUNNER ADVANCE 4
Various evaluations were performed under the following conditions by modifying 051 to a process speed of 300 mm / s. As the paper, plain paper CS-680 (68 g / m ² ) (Canon Marketing Japan Inc.) was used.

<Image density unevenness>
The image density unevenness was subjected to a durability test in a high temperature and high humidity (30 ° C., 80% RH) environment. The development bias was set so that the initial reflection density was 1.4, and 100,000 test charts with a printing ratio of 5% were output. After outputting 100,000 sheets, an original image in which five solid 20 mm square patches were arranged in the development area was output, and the difference between the maximum value and the minimum value of the image density at the five points was obtained.
The image density was measured by using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an image of a white background portion having a document density of 0.00.
A (very good): density difference less than 0.04 B (good): density difference 0.04 or more and less than 0.08 C (normal): density difference 0.08 or more and less than 0.12 D (bad): Concentration difference 0.12 or more, less than 0.16

<Evaluation of fog>
The fog was evaluated by evaluating the second solid white image according to the following criteria after 100,000 sheets of a test chart having a printing ratio of 5% were used in a low temperature and low humidity (15 ° C., 10% RH) environment. The measurement is performed using a reflectometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku). The white background reflection density worst value after image formation is Ds, and the reflection average density of the transfer material before image formation is Dr. The fog was evaluated using Dr-Ds as the fog amount. Therefore, the smaller the value, the better the fog suppression.
A (very good): fog is less than 1.0 B (good): fog is 1.0 or more and less than 2.0 C (normal): fog is 2.0 or more and less than 3.0 D (bad): fog is present 3.0 or more and less than 4.0

<Spattering>
After 100,000 sheets of durable use was performed using a test chart with a printing ratio of 5% in a high-temperature and high-humidity (30 ° C, 80% RH) environment, a grid pattern (at 1 cm intervals) on a 100 µm (latent image) line Was printed, and the scattering was visually evaluated using an optical microscope.
(Evaluation criteria)
A (very good): The line is very sharp and there is almost no scattering.
B (good): The line is sharp with only slight scattering.
C (Normal): Slightly scattered but the line is relatively sharp.
D (Poor): There is a lot of scattering, and the line is blurred.
E (very bad): less than D level.

<Evaluation of gasp>
After a durable use of 100,000 sheets using a test chart with a printing ratio of 5% in a high temperature and high humidity (30 ° C., 80% RH) environment, a halftone (30H) image was formed, and this image was visually observed. Observed and evaluated for roughness based on the following criteria. The 30H image is a value obtained by displaying 256 gradations in hexadecimal, and is a halftone image when 00H is solid white (non-image) and FFH is solid black (entire image).
(Evaluation criteria)
A (very good): It does not feel rust and is smooth.
B (good): There is not much feeling of roughness.
C (Normal): There is a slight rustling feeling, but there is no problem.
D (Poor): There is a feeling of roughness and is a problem.
E (very bad): less than D level.

<Poor coating>
In a low-temperature and low-humidity (15 ° C., 10% RH) environment, 1000 solid white images are passed, and the coatability on the developing sleeve is visually observed and evaluated.
(Evaluation criteria)
○: No problem in coat properties ×: Coat failure occurred

  In each of the above evaluation items, all of the toners of Example 1 were judged as A.

(Production example of toners 2 to 15)
Toners 2 to 15 were obtained in the same manner as in Toner 1 except that the type and amount of magnetic iron oxide particles used as the external additive were changed as shown in Table 2.

<Production Example of Toner 16>
Toner 16 was obtained in the same manner as in Toner 1 except that strontium titanate (number average particle size 1.10 μm) was used instead of the magnetic iron oxide particles used as the external additive.

<Production Example of Toner 17>
Toner 17 was obtained in the same manner as in Toner 1 except that only 1.2 parts by mass of silica fine powder was used as an external additive.

<Examples 2 to 13>
Toners 2 to 13 were evaluated in the same manner as in Example 1. The results are shown in Table 3.
Example 2 was the same evaluation result as Example 1.
In Example 3, the roughness was B evaluation. Since the amount ratio Wb / Wa of Al element dissolved in acid and alkali is 0.60, the surface state of the magnetic iron oxide particles is slightly different, which slightly affects the charging effect and affects the roughness. it is conceivable that.
In Example 4, the roughness was C evaluation. Since the amount ratio Wb / Wa of Al element dissolved in acid and alkali is 0.70, the surface state of the magnetic iron oxide particles is slightly different, which slightly affects the charge imparting effect and reduces roughness. it is conceivable that.
In Examples 5 and 6, fog was evaluated as B. In Example 5, since the number average particle diameter of the magnetic iron oxide particles was 0.05 μm, non-electrostatic adhesion with the toner was increased, and it was difficult to peel from the toner, so it was considered that the fog was affected. It is done. Further, in Example 6, since the number average particle diameter of the magnetic iron oxide particles is 1.0 μm, it is considered that the charge application effect is reduced due to the decrease in the coverage with respect to the toner, and the fog is affected.
In Example 7, fog was C evaluation. Since the number average particle diameter of the magnetic iron oxide particles is as large as 1.10 μm, the effect of imparting charge to the toner is further reduced, which is considered to have affected fog.
In Examples 8 and 9, scattering was B evaluation. In Example 8, since the surface Al amount of the magnetic iron oxide particles is as small as 0.05% by mass, it is considered that the effect of imparting charge to the toner is reduced and the scattering is deteriorated. In Example 9, since the surface Al amount of the magnetic iron oxide particles is as large as 10% by mass, the peelability between the toner and the magnetic iron oxide particles is slightly deteriorated, the effect of imparting charge to the toner is reduced, and the scattering is deteriorated. Conceivable.
In Example 10, scattering was C evaluation. Since the surface iron content of the magnetic iron oxide particles is as large as 11% by mass, the releasability between the toner and the magnetic iron oxide particles is further deteriorated, the effect of imparting charge to the toner is reduced, and the scattering is deteriorated. It is thought that.
In Examples 11 and 12, the image density unevenness was B evaluation. In Example 11, since the amount of magnetic iron oxide particles added was as small as 0.01% by mass, the effect of imparting charge to the toner was not sufficient, and it was considered that the image density unevenness was slightly affected. In Example 12, the amount of magnetic iron oxide particles added was as large as 10% by mass, so that the magnetic iron oxide particles did not peel sufficiently and remained in part of the toner, resulting in a toner having a mixture of positive chargeability. It is considered that the image density unevenness was slightly affected.
In Example 13, the image density unevenness was C evaluation. Since the amount of magnetic iron oxide particles added is as large as 11% by mass, the toner inherent in the magnetic iron oxide particles leaks further, which is considered to have affected the image density unevenness.
In Examples 4 to 13 (Toners 4 to 13), Reference Examples 4 to 13 were used.

<Comparative Examples 1-4>
Toners 14 to 17 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.
In Comparative Examples 1 and 2, scattering and roughness were evaluated as D. Since magnetic iron oxide particles having no Al element on the surface were used, it was considered that there was no charge imparting effect, and scattering and roughness were deteriorated.
In Comparative Example 3, fog was evaluated as D, and scattering and roughness were evaluated as E. External addition of strontium titanate having positive chargeability to the toner, fogging, scattering, and roughness were worsened. This is presumably because strontium titanate decreased the charge amount of the toner because the toner and strontium titanate were not sufficiently separated.
In Comparative Example 4, the coating failure was evaluated as x. Since an external additive having a positive charging property is not used, it is considered that the toner is excessively charged and a coating defect on the sleeve is caused.

Claims (3)

A toner containing toner particles containing a binder resin and magnetic iron oxide particles externally added to the toner particles, the magnetic iron oxide particles having an Al element on the surface ,
The amount of the magnetic iron oxide particles externally added to the toner particles is 1.0 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner particles;
Number average particle diameter of magnetic iron oxide particles, negatively chargeable toner according to claim der Rukoto least 0.19μm below 0.10 .mu.m. The negatively chargeable toner according to claim 1 , wherein the amount of Al element present on the surface of the magnetic iron oxide particles is 0.05% by mass or more and 10% by mass or less with respect to the Fe element. The magnetic iron oxide particles have a ratio (Wb / Wa) of an Al element dissolution amount Wa when dissolved with an acid to an Al element dissolution amount Wb when dissolved with an alkali of 0.60 or less. Item 3. The negatively chargeable toner according to Item 1 or 2 .