JP4602612B2 - Method for evaluating electrophotographic toner, electrophotographic toner, two-component developer, and method for producing electrophotographic toner - Google Patents

Description

表１から、トナーチップ状物の内部状態において、５μｍ以上の気泡、異物、クラックが存在することにより、粉砕性が良好となることが分かる。
【００５４】
【発明の効果】
本発明によれば、より精密な電子写真用トナーの評価方法を提供すると共に、この評価方法によって選別された粉砕しやすい電子写真用トナー、このトナーを用いた２成分系現像剤及び電子写真用トナーの製造方法が提供され、電子写真方式による画像形成分野に寄与するところはきわめて大きいものである。
【図面の簡単な説明】
【図１】トナーチップ状物の内部に気泡が存在する状態を示した図である。
【図２】トナーチップ状物の断面に異物が存在する状態を示した図である。
【図３】トナーチップ状物の内部にクラックが存在する状態を示した図である。
【図４】トナーチップ状物の表層付近にクラックが集中している状態を示した図である。
【図５】本発明の評価方法に用いる装置を示した図である。
【符号の説明】
１ トナーチップ状物
２ ＸＹＺステージ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic toner evaluation method, an electrophotographic toner, a two-component developer, and an electrophotographic toner manufacturing method.
[0002]
[Prior art]
When determining whether or not the electrophotographic toner used for image formation by the electrophotographic method is in a state suitable for the electrophotographic method, the average particle size, particle size distribution, sphericity, etc. of the toner are usually determined. It is measured and evaluated.
[0003]
However, such an evaluation method has a problem that precise evaluation, in particular, the presence or absence of bubbles, the presence or absence of cracks, the concentration level of cracks, and the presence or absence of foreign matter cannot be accurately grasped.
[0004]
In addition, there is a method of evaluation based on observation of the inside of the toner with an optical microscope, but there is a problem in that it cannot be observed up to a sufficient depth.
[0005]
[Problems to be solved by the invention]
The present invention solves such conventional problems and provides a more accurate electrophotographic toner evaluation method, as well as an electrophotographic toner that is easily pulverized and selected by this evaluation method. It is an object of the present invention to provide a method for producing a two-component developer and an electrophotographic toner.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present inventor has intensively studied focusing on toner evaluation means, and as a result, has found that the above problems can be solved by observing using infrared rays. Based on this, the present invention has been completed.
[0007]
That is, according to the present invention, first, a toner composition composed of at least a resin, a pigment, and a charge control agent is melt-kneaded and then solidified to form a chip-like product as described in the following (1) to (4). An evaluation method for an electrophotographic toner, wherein any or all states are observed using infrared rays. (1) Presence or absence of bubbles having a diameter of 5 μm or more inside the chip-like material. (2) Presence or absence of cracks inside the chip-like material. (3) Presence or absence of foreign matters having a diameter of 5 μm or more inside the chip-like material. (4) Presence or absence of cracks concentrated only in the vicinity of the surface of the chip-like object.
[0008]
The first invention includes a method for evaluating an electrophotographic toner in which the infrared wavelength is 0.4 to 1.9 μm.
According to the present invention, secondly, any or all of the electrophotographic toner described in the following (5) to (8), which is selected by the evaluation method according to the first invention, is provided.
(5) A toner for electrophotography, wherein bubbles having a diameter of 5 μm or more are present inside the chip-like material.
(6) A toner for electrophotography, wherein cracks are present inside the chip-like material.
(7) A toner for electrophotography, wherein foreign matters having a diameter of 5 μm or more are present inside the chip-like material.
(8) A toner for electrophotography, characterized in that cracks are not concentrated only in the vicinity of the surface layer of the chip-like material.
[0009]
According to the present invention, thirdly, there is provided an electrophotographic toner obtained by pulverizing the electrophotographic toner according to the second invention to an average particle size of 5 to 10 μm.
According to the present invention, fourthly, there is provided a two-component developer characterized by comprising the electrophotographic toner according to the third invention and a carrier having a particle size of 30 to 500 μm.
[0010]
According to the present invention, fifthly, there is provided a method for producing an electrophotographic toner in which a toner composition comprising at least a pigment-dispersed resin and a charge control agent is melt-kneaded and then cooled to crush the solidified product. Thus, an electrophotographic toner production method using the electrophotographic toner according to the second invention as the solidified product is provided.
[0011]
The fifth invention includes a method for producing an electrophotographic toner that does not use a solvent when the pigment is dispersed in the resin.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, a chip-like product (hereinafter simply referred to as a chip-like product) obtained by melting and kneading the toner composition on the sample stage with an optical microscope using a light source exhibiting high brightness up to the infrared region and then solidifying. In some cases, infrared rays are irradiated, and the intensity of the reflected wave is detected by an infrared video camera to observe the internal structure.
Examples of changes in the internal structure that can be detected include bubbles, cracks, internal separation, surface separation, and interface state.
The internal structure of the chip-like object has not been sufficiently observed so far, and the actual state and state can be understood by the evaluation method of the present invention (FIGS. 1 to 4).
[0013]
In the present invention, the detection depth in the depth direction of the infrared ray is determined by the spectral characteristics of the chip-like material, but the absorption wavelength of the resin occupying most of the chip-like material is 3 μm or later, and a shorter wavelength is used. In some cases it is transparent.
However, in the chip-like material, the pigment is densely dispersed in the resin, light is absorbed by the pigment portion, and the actual detection depth in the depth direction is greatly reduced to 500 μm or less.
The infrared wavelength range to be used is 0.4 to 1.9 μm in relation to the spectral characteristics of the detector.
When the IR-CCD is used, the wavelength range used is further narrowed to 0.4 to 1.2 μm.
Any light source may be used as long as it can radiate from the visible region to the infrared region. Usually, a halogen lamp or the like is used.
[0014]
As described above, the observation state method using the present infrared allows the depth direction of the chip-like object to be observed by the same observation method as that of a conventional optical microscope, and is very effective for detecting foreign matter in the depth direction. is there.
The resolution is similar to that of an optical microscope and has a resolution of 2 to 3 μm.
Therefore, extremely fine foreign matter detection is possible.
[0015]
Hereinafter, the electrophotographic toner is sometimes simply referred to as toner.
Examples of the resin used in the toner composition of the present invention include polystyrene resin, epoxy resin, polyester resin, polyamide resin, styrene acrylic resin, styrene methacrylate resin, polyurethane resin, vinyl resin, polyolefin resin, styrene butadiene resin, phenol resin, and butyral. Resins, terpene resins, polyol resins and the like can be mentioned.
[0016]
Examples of the vinyl resin include polystyrene, poly-p-chlorostyrene, polyvinyltoluene and other styrene and its substituted homopolymer, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer. Polymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methacrylic copolymer Acid methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer Coalescence, styrene-vinyl ethyl ether Copolymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer, Styrene-acrylonitrile-indene copolymer, Styrene-maleic acid copolymer, Styrene-maleic acid ester copolymer Examples thereof include styrene copolymers such as polymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, and polyvinyl acetate.
[0017]
The polyester resin is produced from a divalent alcohol as shown in the following group A and a dibasic acid salt as shown in the group B, and further trivalent as shown in the group C. You may add the above alcohol or carboxylic acid as a 3rd component.
[0018]
[Group A] ethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4 butanediol, neopentyl glycol, 1,4 butenediol, 1,4-bis (hydroxymethyl) Cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene (2,2) -2,2′-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -2,2′-bis ( 4-hydroxyphenyl) propane and the like.
[0019]
[Group B] 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, linolenic acid, Or esters of these acid anhydrides or lower alcohols.
[0020]
[Group C] Trivalent or higher alcohols such as glycerin, trimethylolpropane and pentaerythritol, and trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid.
As the polyol resin, an alkylene oxide adduct of an epoxy resin and a dihydric phenol or a compound having one active hydrogen in the molecule that reacts with the glycidyl ether and the epoxy group, and two active hydrogens that react with the epoxy resin in the molecule. Examples include those structured by reacting with at least one compound.
[0021]
As the pigment used in the present invention, the following are used.
Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.
[0022]
Examples of yellow pigments include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake. .
Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, and indanthrene brilliant orange GK.
[0023]
Examples of red pigments include Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B.
[0024]
Examples of purple pigments include fast violet B and methyl violet lake.
[0025]
Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.
[0026]
Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.
These can use 1 type (s) or 2 or more types.
[0027]
Especially for color toners, uniform dispersion of good pigments is essential, and instead of putting the pigments directly into a large amount of resin, a master batch is prepared in which the pigments are dispersed at a high concentration and then diluted. The method of charging is preferable.
In this case, a solvent is generally used to help dispersibility. However, there is a problem such as the environment, and in the present invention, water is used for dispersion.
When water is used, temperature control is important so that residual moisture in the masterbatch does not become a problem.
[0028]
In the toner of the present invention, a charge control agent is blended (internally added) inside the toner particles.
However, it may be used by mixing (external addition) with toner particles.
The charge control agent enables optimal charge amount control according to the development system.
For controlling the toner to be positively charged, nigrosine and quaternary ammonium salts, triphenylmethane dyes, imidazole metal complexes and salts can be used alone or in combination of two or more.
Further, salicylic acid metal complexes, salts, organic boron salts, calixarene compounds, and the like are used to control the toner to be negatively charged.
[0029]
In addition, a release agent can be internally added to the toner in the present invention in order to prevent an offset at the time of fixing.
Examples of the release agent include natural waxes such as candelilla wax, carnauba wax, and rice wax, montan wax, paraffin wax, sazol wax, low molecular weight polyethylene, low molecular weight polypropylene, and alkyl phosphate ester.
The melting point of these release agents is preferably 65 to 90 ° C.
When the temperature is lower than 65 ° C., blocking during storage of the toner is likely to occur, and when the temperature is higher than 90 ° C., offset is likely to occur in a region where the fixing roller temperature is low.
[0030]
As an example of a method for producing the toner according to the present invention, first, the above-mentioned resin, pigment or dye as a colorant, charge control agent, release agent, and other additives are mixed with a mixer such as a Henschel mixer. After thorough mixing, batch type twin rolls, Banbury mixer and continuous twin screw extruder, for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd., KCK Heat from a 2-screw extruder manufactured by Ikegai, a PCM type twin-screw extruder manufactured by Ikekai Tekko Co., Ltd., a KEX-type twin-screw extruder manufactured by Kurimoto Tekkosho, and a continuous single-screw kneader, for example, Kousida manufactured by Buss The constituent materials are well kneaded using a kneader, and after rolling and cooling, cutting is performed.
The internal structure evaluation of the chip shape after this cutting is performed by this evaluation method.
[0031]
FIG. 5 shows an apparatus used for the evaluation method of the present invention.
Place the chip 1 on the stage of a microscope using infrared rays, bring the objective lens close to the sample surface, perform focus adjustment, shift the focus from the sample surface to the inside of the sample, and observe the state inside the sample. .
Reference numeral 2 denotes an XYZ stage.
Observation is performed with an infrared camera, contrast adjustment is performed with a camera controller, and then observation is performed with a television monitor.
[0032]
In the pulverization step, as the particle size of the toner becomes smaller, it becomes difficult to pulverize, and a phenomenon that the pulverization feed amount decreases occurs, and a device for improving the pulverization property is required.
Therefore, it was found that the pulverization property is improved by observing various internal structures of the toner kneaded product and determining the internal structure of the chip-like product before pulverization as follows by this evaluation method using infrared rays. .
(1) A bubble having a diameter of 5 μm or more exists inside the chip-like object.
(2) A crack is present inside the chip-like object.
(3) A foreign substance having a diameter of 5 μm or more exists inside the chip-like object.
(4) Cracks are not concentrated only near the surface of the chip-like material.
[0033]
Chips after cutting are crushed, coarsely pulverized using a hammer mill, etc., and further pulverized by a fine pulverizer or mechanical pulverizer using a jet stream, and a classifier or Coanda effect using a swirling airflow Is classified to a predetermined particle size by a classifier using
Thereafter, an additive composed of inorganic particles or the like is adhered or fixed to the particle surface, passed through a sieve of 250 mesh or more, and coarse particles and aggregated particles are removed to obtain the toner of the present invention.
[0034]
Further, when used as a two-component developer, a two-component developer is obtained by mixing with a magnetic carrier described later at a predetermined mixing ratio.
The weight average particle size of the toner is 5 to 10 μm, more preferably 6 to 8 μm.
If the weight average particle size is less than 5 μm, problems such as contamination in the machine due to toner scattering during long-term use, image density reduction in a low-humidity environment, and poor photoreceptor cleaning are likely to occur.
When the weight average particle diameter exceeds 10 μm, the resolution of minute spots of 100 μm or less is not sufficient, and the image quality tends to be inferior due to many scattering to non-image areas.
[0035]
The toner of the present invention can also be used as a one-component developer used in a contact or non-contact development system.
As the contact or non-contact development method, known ones are adopted, for example, a contact development method using an aluminum sleeve, a contact development method using a conductive rubber belt, a conductive resin layer containing carbon black or the like on the surface of an aluminum base tube. There is a non-contact developing method using a developing sleeve formed with a film.
[0036]
Further, when a magnetic toner is used, magnetic particles may be internally added to the toner particles.
Examples of the magnetic material include ferromagnetic materials such as ferrite, magnetite, iron, nickel, cobalt, and alloys thereof.
The average particle size of the magnetic material is preferably 0.1 to 1 μm.
The content of the magnetic material is preferably 10 to 70 parts by weight with respect to 100 parts by weight of the toner.
[0037]
As the carrier used in the two-component developer, a known carrier can be used. For example, magnetic particles such as iron powder, ferrite powder, nickel powder, and magnetite powder, or the surface of these magnetic particles are made of a fluorine-based resin or vinyl. Examples thereof include those treated with a resin, a silicone resin, etc., or magnetic particle-dispersed resin particles in which magnetic particles are dispersed in the resin.
These magnetic carriers have an average particle size of 30 to 500 μm, preferably 30 to 100 μm.
[0038]
When the average particle diameter of the carrier is within this range, the charge amount of the toner can be made more uniform by combining with the toner of the present invention when the toner concentration inside the developing device is in the range of 2 to 10% by weight. .
If it is less than 30 μm, the carrier particles are likely to adhere to the photoreceptor, and the stirring efficiency with the toner is deteriorated, and it becomes difficult to obtain a uniform charge amount of the toner.
Further, when the thickness exceeds 100 μm, fine image reproducibility is deteriorated.
[0039]
Furthermore, as described above, the two-component developer of the present invention can be used by adding inorganic powder to the toner as a fluidity improver.
As the inorganic fine powder used in the present invention, Si, Ti, Al, Mg, Ca, Sr, Ba, In, Ga, Ni, Mn, W, Fe, Co, Zn, Cr, Mo, Cu, Ag, V, Examples thereof include oxides such as Zr and composite oxides.
Of these, fine particles of silicon dioxide (silica), titanium dioxide (titania), and alumina are suitable, and it is also effective to perform a surface modification treatment with a hydrophobizing agent or the like.
Hydrophobizing agents include dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane. , P-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, hexaphenyldisilazane, hexatolyldisilazane, and the like.
[0040]
The inorganic fine powder is preferably 0.1 to 2% by weight based on the toner.
If the amount is less than 0.1% by weight, the effect of improving toner aggregation is poor. If the amount exceeds 2% by weight, problems such as toner scattering between fine wires, contamination in the machine, scratches and abrasion of the photoreceptor tend to occur. Become.
[0041]
In addition, the developer of the present invention may further contain other additives within a range that does not substantially adversely affect, for example, a lubricant powder such as Teflon powder, zinc stearate powder, polyvinylidene fluoride powder, cerium oxide powder, carbonization Abrasives such as silicon powder and strontium titanate powder, for example, conductivity imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder can be used in small amounts as a developability improver.
[0042]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited at all by these Examples.
Note that “parts” are all parts by weight.
[0043]
Example 1
Binder resin: Polyester resin 100 parts Colorant: Copper phthalocyanine blue pigment 3.5 parts Charge control agent: Salicylic acid zinc salt 3 parts The above raw materials are thoroughly mixed with a mixer, and then kneaded at a temperature of 120 ° C by a twin screw extruder. Was melt kneaded.
The kneaded product was rolled and cooled, coarsely pulverized by a cutter mill, pulverized by a fine pulverizer using a jet stream, and then classified into a particle size distribution having an average particle size of 7 μm using a swirling air classifier.
Further, 1 part of silica differential powder was mixed with 100 parts of the base colored particles by a super mixer.
The kneading was performed without evacuation. The toner thus obtained was mixed at a ratio of 2.5 parts to 97.5 parts of a carrier in which ferrite particles having an average particle diameter of 100 μm and a silicon resin were coated on the surface to prepare a two-component developer.
As a result of microscopic observation of the toner chip-like product using infrared rays, as shown in FIG. 1, many bubbles of 5 μm or more existed in the thickness direction inside the chip-like product.
The pulverizability of this chip-like product was as shown in Table 1, and the pulverizability was good.
[0044]
Example 2
Resin: Polyester resin 100 parts Colorant: Quinacridone-based magenta pigment 8 parts Charge control agent: Salicylic acid zinc salt 5 parts The above raw materials are kneaded, pulverized and classified in the same manner as in Example 1, and the average particle diameter is 7 µm. Classification into particle size distribution.
Furthermore, 1 part of silica fine powder was mixed with 100 parts of base coloring particles by a super mixer.
As a result of observing the internal state of the toner chip-like product by this evaluation method using an infrared microscope, foreign matter having a size of 5 μm or more was present in the cross-section of the chip-like product as shown in FIG.
As a result of pulverizing the chip-like material, the pulverization property was good, and the pulverization feed amount as shown in Table 1 was obtained.
[0045]
Example 3
Binder resin: Polyester resin 100 parts Pigment: Carbon black 10 parts Charge control agent: Salicylic acid zinc salt 5 parts The above raw materials are kneaded, pulverized and classified in the same manner as in Example 1, and the average particle size is 7 μm. Classified into distribution.
Furthermore, 1 part of silica fine powder was mixed with 100 parts of base coloring particles by a super mixer.
As a result of evaluating the cross-sectional state of the toner chip-like article by this evaluation method using an infrared microscope, cracks existed in the chip-like article as shown in FIG.
As a result of pulverizing the chip-like material, the pulverization feed amount as shown in Table 1 was obtained, and good pulverization property was exhibited.
[0046]
Example 4
Binder resin: Styrene-methyl acrylate copolymer 100 parts Magnetic body: Iron trioxide 80 parts Charge control agent Salicylic acid zinc salt 4 parts The above raw materials are kneaded, pulverized and classified in the same manner as in Example 1, The average particle size was classified into a particle size distribution of 7 μm.
Further, 1 part of silica fine powder was mixed with 100 parts of the base colored particles by a super mixer.
As a result of observing the internal state of the toner chip-like material by this evaluation method using infrared rays, bubbles of 5 μm or more were present as shown in FIG.
As a result of pulverizing this chip shape, a pulverization feed amount as shown in Table 1 was obtained, and good pulverization characteristics were exhibited.
[0047]
Example 5
A toner was prepared in the same manner as in Example 2 except that the master batch dispersed in water was used in the colorant of Example 2.
As a result of observing the detection of foreign matter inside the toner chip-like material by this evaluation method using infrared rays, bubbles of 5 μm or more similar to those in FIG. 1 were present inside the chip-like material.
As a result of pulverizing the chip-like material, the pulverization feed amount as shown in Table 1 was obtained, and good pulverization property was exhibited.
[0048]
Example 6
In Example 3, a toner was prepared in the same manner as in Example 3 except that a styrene acrylic resin was used instead of the polyester resin.
As a result of observing the internal state of the toner chip-like material by this evaluation method using infrared rays, cracks were present in the cross section as in FIG.
As a result of pulverizing this chip-like product, the pulverization feed amount as shown in Table 1 was obtained, and good pulverization property was exhibited.
[0049]
Example 7
In Example 1, a two-component developer was prepared in the same manner as in Example 1 except that the barrel temperature in the kneading step was set to 110 ° C., and the same evaluation as in Example 1 was performed.
As a result of observing the internal state of the toner chip-like product by this evaluation method using infrared rays, many bubbles similar to those in FIG. 1 were present inside the chip-like product.
As a result of grinding this chip-like product, as shown in Table 1, the grindability was good.
[0050]
Comparative Example 1
A two-component developer was produced in the same manner as in Example 1 except that the kneading step was performed by evacuation in Example 1, and the same evaluation as in Example 1 was performed.
As a result of evaluating the internal state of the toner chip-like product by this evaluation method using infrared rays, no bubbles were present inside the chip-like product.
As a result of pulverizing this chip-like material, as shown in Table 1, the pulverizability was not good.
[0051]
Comparative Example 2
In Example 5, a toner was prepared in the same manner as in Example 5 except that the kneading process was performed by evacuation, and the same evaluation as in Example 5 was performed.
As a result of observing the internal state of the toner chip-like product by this evaluation method using infrared rays, no bubbles were present inside the chip-like product.
As a result of pulverizing this chip-like material, the pulverization feed amount as shown in Table 1 was obtained, and the pulverization property was not good.
[0052]
Comparative Example 3
A toner was produced in the same manner as in Example 3 except that the kneading process was performed by evacuating the kneading process in Example 3, and the same evaluation as in Example 3 was performed.
As a result of observing the cross-sectional state of the toner chip-like material with this evaluation method using infrared rays, no bubbles are present inside the chip-like material, and cracks are concentrated near the surface layer as shown in FIG. Was. As a result of pulverizing the chip-like material, a pulverization feed amount was obtained as shown in Table 1, and the pulverization property was not good.
[0053]
[Table 1]

From Table 1, it can be seen that the presence of bubbles, foreign matter, and cracks of 5 μm or more in the internal state of the toner chip-like product improves the grindability.
[0054]
【The invention's effect】
According to the present invention, a more precise method for evaluating electrophotographic toner is provided, and an electrophotographic toner selected by this evaluation method and easily pulverized, a two-component developer using the toner, and an electrophotographic toner A toner manufacturing method is provided and contributes greatly to the field of image formation by electrophotography.
[Brief description of the drawings]
FIG. 1 is a view showing a state in which bubbles are present inside a toner chip-like object.
FIG. 2 is a diagram illustrating a state in which foreign matter exists on a cross section of a toner chip-like object.
FIG. 3 is a diagram illustrating a state in which a crack exists inside a toner chip-like material.
FIG. 4 is a diagram illustrating a state in which cracks are concentrated near the surface layer of a toner chip-like material.
FIG. 5 is a diagram showing an apparatus used in the evaluation method of the present invention.
[Explanation of symbols]
1 Toner chip-like product 2 XYZ stage

Claims (5)

A toner composition comprising at least a resin, a pigment, and a charge control agent is melt-kneaded and then solidified to form a chip-like product. The chip-like product is at least one of the following (1) to (4) using infrared rays. or by the observation, evaluation method of pulverized toner manufacturing chip-like product and evaluating whether or not the chip-like material which satisfies at least one defined in the following (5) to (8).
(1) Presence or absence of bubbles having a diameter of 5 μm or more inside the chip-like material. (2) Presence or absence of cracks inside the chip-like material. (3) Presence or absence of foreign matters having a diameter of 5 μm or more inside the chip-like material. (4) Presence or absence of cracks concentrated only in the vicinity of the surface of the chip-like object.
(5) Bubbles having a diameter of 5 μm or more exist inside the chip-like material. (6) There are cracks inside the chip-like material. (7) Foreign matter having a diameter of 5 μm or more exists inside the chip-like material. (8) Cracks are not concentrated only near the surface of the chip-like object. The method for evaluating a chip-like product for producing a pulverized toner according to claim 1, wherein the infrared wavelength is 0.4 to 1.9 μm. A method for producing an electrophotographic toner, comprising melting and kneading a toner composition comprising at least a pigment-dispersed resin and a charge control agent, and then pulverizing a solidified product obtained by cooling. The chip-shaped material satisfying at least one of the following (5) to (8) selected by the evaluation method of the chip-shaped material for producing pulverized toner according to any one of 1 to 2 is used: A method for producing a photographic toner.
(5) Bubbles having a diameter of 5 μm or more exist inside the chip-like material. (6) There are cracks inside the chip-like material. (7) Foreign matter having a diameter of 5 μm or more exists inside the chip-like material. (8) Cracks are not concentrated only near the surface of the chip-like object. The method for producing an electrophotographic toner according to claim 3, wherein the crushing feed amount of the chip-like material is 4.5 kg / h to 5.4 kg / h. 5. The method for producing an electrophotographic toner according to claim 3, wherein a solvent is not used when dispersing the pigment in the resin.

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