CN112119356A - Toner for developing electrostatic image and method for producing toner for developing electrostatic image - Google Patents

Abstract

A toner for developing electrostatic images, comprising toner particles and an external additive, wherein the toner particles comprise a binder resin containing a crystalline polyester resin, a colorant and a release agent, the crystalline polyester resin comprises sebacic acid as an acid component and 1, 10-decanediol as an alcohol component, and has a mass average molecular weight of 3000 to 5000, and the toner particles contain 5 to 10% by mass.

Description

Toner for developing electrostatic image and method for producing toner for developing electrostatic image

technical field

The present invention relates to a toner for developing electrostatic images and a method for producing the toner for developing electrostatic images. More specifically, the present invention relates to a toner for developing an electrostatic image which exhibits excellent storage stability and can be fixed at a low temperature, and a method for producing the toner for developing an electrostatic image.

Background technique

Conventionally, in electrophotographic printers and copiers, reduction in fixing temperature and reduction in standby time have been required from the viewpoint of energy saving. Along with this, excellent low-temperature fixing performance is required for the toner to be used. If the melting point of the resin is lowered in order to improve the low-temperature fixing performance, the glass transition temperature of the toner is lowered, and the storage stability is deteriorated. Patent Document 1 proposes a method of preventing a drop in the glass transition temperature by performing heat treatment at the time of toner production. In addition, Patent Document 2 proposes a method of achieving both low-temperature fixability and storage stability by forming a core-shell structure after pulverizing and classifying the toner.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2010-139752

Patent Document 2: Japanese Patent Laid-Open No. 2015-157715

SUMMARY OF THE INVENTION

Here, in order to obtain low-temperature fixability, the use of crystalline resins having sharp melting properties is being studied. However, especially for a toner obtained through the steps of cooling and solidifying after kneading, followed by pulverization and classification, when the amorphous resin and the crystalline resin are melt-kneaded, if the amorphous resin and the crystalline resin are melt-kneaded, the When the resins are polyester or the like, the glass transition temperature is greatly lowered, and the storage stability tends to deteriorate. When the dispersibility of the amorphous resin and the crystalline resin decreases, the charge amount of the toner tends to become uneven. In addition, when the glass transition temperature is lowered, the toner tends to be blocked during storage. In addition, the methods described in Patent Documents 1 and 2 require new facilities, and the productivity tends to decrease, resulting in an increase in cost. Therefore, there is a need for a toner that can utilize existing equipment and that achieves both low-temperature fixability and storage stability.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a toner for developing electrostatic images and a method for producing a toner for developing electrostatic images, which can utilize existing equipment and can achieve both low-temperature fixability and storage stability. .

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, they found that the molecular weight of the crystalline polyester resin and the carbon chains of the diol and dicarboxylic acid monomer molecules constituting the crystalline polyester resin affect low-temperature fixability and storage stability. sex. Furthermore, the present inventors have found that the above-mentioned problems can be solved by blending a predetermined amount of a crystalline polyester resin having a predetermined molecular weight containing sebacic acid as an acid component and 1,10-decanediol as an alcohol component in toner particles. The subject has been solved and the present invention has been completed.

A toner for developing electrostatic images according to one aspect of the present invention that solves the above-mentioned problems includes toner particles and an external additive, and the toner particles include a binder resin including a crystalline polyester resin, a colorant, and a mold release The crystalline polyester resin contains sebacic acid as an acid component, 1,10-decanediol as an alcohol component, a mass average molecular weight of 3,000 to 5,000, and 5 to 10% by mass in the toner particles.

A method for producing a toner for developing an electrostatic image according to an aspect of the present invention that solves the above-mentioned problems is the method for producing the above-mentioned toner for developing an electrostatic image, which includes kneading, cooling and solidifying, and then pulverizing and classifying. manufacturing process.

Detailed ways

<Toner for Electrostatic Image Development>

The electrostatic image developing toner (hereinafter also referred to as toner) according to an embodiment of the present invention contains toner particles and an external additive. The toner particles contain a binder resin containing a crystalline polyester resin, a colorant, and a release agent. The crystalline polyester resin contains sebacic acid as an acid component and 1,10-decanediol as an alcohol component, has a mass average molecular weight of 3,000 to 5,000, and is contained in toner particles in an amount of 5 to 10% by mass. In addition, the toner used in the image forming method in the electrophotographic system may be a two-component toner used with a carrier or a one-component toner not using a carrier. Each of them will be described below.

(toner particles)

The toner particles contain a binder resin containing a crystalline polyester resin, a colorant, and a release agent.

·Binder resin

The binder resin is blended for the purpose of dispersing the colorant contained in the toner, and curing the colorant after being melted on the surface of the recording medium by the heat of the fixing roller during the fixing process during printing. Fusing on the surface of the recording medium.

As the binder resin, the crystalline polyester resin of the present embodiment and a binder resin other than the crystalline polyester resin of the present embodiment are used in combination.

The crystalline polyester resin of the present embodiment is blended to improve both low-temperature fixability and storage stability of the toner. The crystalline polyester resin of the present embodiment contains sebacic acid as an acid component and 1,10-decanediol as an alcohol component.

By including 1,10-decanediol as the alcohol component, both the low-temperature fixability and storage stability of the obtained toner can be improved.

The mass average molecular weight of the crystalline polyester resin is preferably 3,000 or more. In addition, the mass average molecular weight of the crystalline polyester resin is preferably 5,000 or less. When the mass average molecular weight is less than 3000, the storage stability of the toner tends to decrease. On the other hand, when the mass average molecular weight exceeds 5,000, the low-temperature fixability of the toner tends to decrease.

In the toner particles, the content of the crystalline polyester resin is preferably 5% by mass or more. In addition, in the toner particles, the content of the crystalline polyester resin is preferably 10% by mass or less. When the content is less than 5% by mass, the low-temperature fixability of the toner is poor. On the other hand, when the content exceeds 10% by mass, the storage stability of the toner is poor.

The melting point of the crystalline polyester resin is not particularly limited. As an example, the melting point is preferably 70°C or higher. In addition, the melting point is preferably 76°C or lower. By making the melting point within the above range, the fixability of the toner becomes favorable. In addition, in the present embodiment, the melting point can be calculated by measuring the melting temperature in thermal analysis using a differential scanning calorimeter. The binder resin is not particularly limited.

The method for producing the crystalline polyester resin is not particularly limited, and it can be produced by a conventional polyester polymerization method in which an acid component and an alcohol component are reacted, and examples thereof include direct polycondensation and transesterification.

The production of the crystalline polyester resin can be carried out in a polymerization temperature range of 180° C. or higher and 230° C. or lower, and the reaction system can be reduced in pressure if necessary, and the reaction can be performed while removing water and alcohol generated during condensation. When the monomer is insoluble or incompatible at the reaction temperature, a solvent with a high boiling point can be added as a dissolving aid to dissolve it. In the polycondensation reaction, the dissolving auxiliary solvent is distilled off. In the copolymerization reaction, in the presence of a monomer with poor compatibility, it is preferable to condense the monomer with poor compatibility with the acid or alcohol to be polycondensed with the monomer in advance, and then perform polycondensation together with the main component.

Examples of catalysts that can be used in the production of crystalline polyester resins include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium; As a phosphorus oxy compound, a phosphorus oxy compound, an amine compound, etc., the following compounds are mentioned specifically,.

For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, naphthenic acid Manganese, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, antimony triphenyl, antimony tributyl, tin formate, tin oxalate, tin tetraphenyl, dibutyl Tin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconium oxycarbonate, zirconium oxyacetate, zirconyl stearate, zirconium octoate, germanium oxide, phosphorous acid Compounds such as triphenyl ester, tris(2,4-tert-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, triphenylamine, etc.

The binder resin that can be used in combination with the crystalline polyester resin of the present embodiment is not particularly limited. As an example, the binder resin is styrene-based copolymers such as polystyrene, styrene-methyl acrylate copolymer, and styrene-acrylonitrile copolymer, and polyesters other than the crystalline polyester resin of the present embodiment described above. Resin, epoxy resin and other resin materials. These binder resins can also be used in combination. Among these, as the binder resin to be used in combination, polyester is preferable from the viewpoint of easy coloring and obtaining a brightly colored toner.

The binder resin of the present embodiment preferably contains an amorphous resin among the above-mentioned resin materials. In addition, the amorphous resin preferably has a mass average molecular weight of 4,000 to 150,000 and a softening point of 95 to 125°C. The mass average molecular weight is preferably 4,000 or more, and more preferably 5,000 or more. In addition, the mass average molecular weight is preferably 150,000 or less, and more preferably 12,000 or less. The softening point is preferably 90°C or higher, and more preferably 95°C or higher. In addition, the softening point is preferably 125°C or lower, and more preferably 120°C or lower. By making the mass average molecular weight and softening point within the above ranges, the obtained toner exhibits excellent low-temperature fixability and storage stability. In addition, in this embodiment, a mass average molecular weight can be calculated|required by polystyrene conversion by measuring by gel permeation chromatography (GPC), for example. As an apparatus for measuring the mass average molecular weight in terms of polystyrene by GPC, for example, Water 2690 (manufactured by Waters Corporation), and as a column, PLgel 5 μL MIXED-D (manufactured by Polymer Laboratories), etc. . In addition, the softening point can be measured based on ASTM E28-92.

The content of the binder resin other than the crystalline polyester resin of the present embodiment described above is not particularly limited. As an example, the content of the binder resin in the toner is preferably 75% by mass or more. In addition, the content of the binder resin in the toner is preferably 85% by mass or less. By making the content of the binder resin within the above-mentioned range, the obtained toner can easily disperse the colorant appropriately and be easily fixed on the recording medium.

·Colorant

The colorant is blended to provide coloring power to the toner.

The colorant is not particularly limited. To give an example, the coloring agent is carbon black and other coloring agents that exhibit black color such as magnetic powder; copper phthalocyanine, methylene blue, Victoria blue and other coloring agents that exhibit cyan color; rhodamine dyes, dimethylquinacridone, dichloroquine, etc. Acridone, carmine and other colorants exhibiting magenta; benzidine yellow, chrome yellow, naphthol yellow, diazo yellow and other colorants exhibiting yellow. Colorants can be used in combination.

The content of the colorant is not particularly limited. As an example, in the toner, the content of the colorant is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin. In addition, since the masterbatch which disperse|distributed a high density pigment in resin beforehand is marketed, this masterbatch can be purchased and used as a colorant. In this case, the amount of the pigment to be used may be determined in consideration of the concentration of the pigment contained in the master batch so that the concentration of the pigment contained in the toner falls within the above-mentioned range.

·Mold release agent

The release agent is not particularly limited, and various known waxes can be used. As an example, polyolefin waxes such as polyethylene wax and polypropylene wax; branched chain hydrocarbon waxes such as microcrystalline wax; long chain hydrocarbon waxes such as paraffin wax and sasol wax; dioxane such as distearyl ketone Base ketone wax; carnauba wax, montan wax, behenate behenate, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerol tribehenate, 1 , 18-octadecanediol distearate, trimellitic acid tristearate, maleate distearate and other ester waxes; ethylene bisbehenamide, trimellitic acid tristearate Amide and other amide waxes, etc. A release agent can be used in combination. Among these, the release agent is preferably an ester-based wax and a hydrocarbon-based wax.

The content of the release agent is not particularly limited. As an example, the content of the mold release agent may be usually in the range of 1 to 30 parts by mass, preferably in the range of 5 to 20 parts by mass, with respect to 100 parts by mass of the binder resin. The content of the release agent in the toner particles is preferably in the range of 3 to 15% by mass. By making the content of the release agent within the above-mentioned range, in the fixing process at the time of printing, the obtained toner can obtain good release properties between the fixing roller and the printing surface. In addition, the release agent is less likely to ooze out of the toner, and poor charging, filming, and the like are less likely to occur.

·Other ingredients

The toner particles other than the above are, for example, a charge adjuster or the like. The charge adjuster is preferably blended in order to adjust the charge amount of the toner.

The charge adjuster is not particularly limited. To give an example, the charge adjuster is metal complexes such as nigrosine, basic dyes, and monoazo dyes; salts or complexes of carboxylic acids such as salicylic acid and dicarboxylic acid and metals such as chromium, zirconium, and aluminum; Organic dyes; metal salts of naphthenic acids and higher fatty acids; resin-type charge regulators such as alkoxylated amines, quaternary ammonium salt compounds, aromatic polycondensates, etc. Charge adjusters can be used in combination. Among these, from the viewpoint of charging stability, it is preferable that the toner contains a resin-type charge adjuster.

The content of the charge adjuster is not particularly limited. As an example, the toner particles may not contain the charge adjuster, and the content of the charge adjuster is preferably 0.5% by mass or more. In addition, the content of the charge adjuster in the toner particles is preferably 8% by mass or less. By making the content of the charge adjuster within the above-mentioned range, the obtained toner is more excellent in chargeability.

(external additive)

External additives are blended in order to adhere to the surface of the toner particles to improve the charging characteristics of the toner particles, to exist in a state separated from the toner particles to improve the fluidity of the toner, or to improve the printability. of.

The external additive is not particularly limited. As an example, the external additive is negatively charged lubricant particles, positively charged lubricant particles, inorganic oxide particles, and the like. External additives can also be used in combination. External additives can be appropriately selected and used according to the type and purpose of the equipment.

Positively charged lubricant particles are lubricant particles that are positively charged by triboelectric charging with a carrier or a charged sheet. Such lubricant particles are known, and metal salt particles of fatty acids are preferably exemplified. Preferable examples of such metal salts of fatty acids include zinc stearate, aluminum stearate, calcium stearate, magnesium stearate, zinc laurate, zinc myristate, zinc palmitate, zinc oleate, and the like. , among which zinc stearate and magnesium stearate are more preferred. The positively charged lubricant particles may be of a single type or may be a combination of two or more.

Negatively charged lubricant particles are lubricant particles that are negatively charged by triboelectric charging with a carrier or a charged sheet. Such lubricant particles are known, and polytetrafluoroethylene (PTFE), silicone, boron nitride, polymethyl methacrylate (PMMA), and polyvinylidene fluoride are preferably exemplified, and among them, nitride is more preferably exemplified. Boron, Polytetrafluoroethylene (PTFE). The negatively charged lubricant particles may be of a single type or may be a combination of two or more.

The inorganic oxide particles are not particularly limited. As an example, the inorganic oxide particles are silica, alumina, titania, zirconia, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, and the like. Inorganic oxide particles can be used in combination. Among these, the inorganic oxide particles are preferably silica and titania from the viewpoints of excellent fluidity and excellent chargeability of the toner.

It is preferable that the surface of the inorganic oxide particles is hydrophobized. The method of hydrophobizing treatment is not particularly limited. As an example, the method of hydrophobizing treatment is a method in which a conventionally known hydrophobic treatment agent is brought into contact with the surface of the inorganic oxide particles before the hydrophobization treatment, and a hydrophobic functional group or component is bonded or adhered to the surface. Methods of Surface of Inorganic Oxide Particles. The hydrophobizing treatment agent for hydrophobizing the inorganic oxide particles is not particularly limited. As an example, the hydrophobizing treatment agent is octyltriethoxysilane, polydimethylsiloxane, dimethyldichlorosilane, hexamethyldisilazane, and the like. A hydrophobizing treatment agent can also be used in combination.

The addition amount of the external additive in the present embodiment (in the case of using a plurality of types of external additives, the total addition amount) is preferably in the range of 0.05 to 5 parts by mass, and more preferably 0.1 with respect to 100 parts by mass of the toner within the range of to 3 parts by mass. By making the content of the external additive within the above-mentioned range, the fluidity, chargeability, cleaning property, and the like of the obtained toner become favorable.

As described above, the toner of the present embodiment contains the crystalline polyester resin as described above, the crystalline polyester resin contains sebacic acid as the acid component, 1,10-decanediol as the alcohol component, and has a mass average molecular weight of 3,000 ∼5000, contained in the binder resin in an amount of 5 to 10% by mass. This toner can achieve both excellent low-temperature fixability and storage stability.

<Manufacturing method of toner for electrostatic image development>

A method for producing a toner for developing electrostatic images (hereinafter also referred to as a method for producing a toner) according to an embodiment of the present invention is a method for producing the above-mentioned toner for developing electrostatic images, which includes kneading After that, it is cooled and solidified, and then pulverized and classified. It should be noted that each of the above steps is a step employed in a conventionally known toner manufacturing method. That is, the toner manufacturing method of this embodiment can manufacture a toner by a conventionally well-known method using a conventionally well-known manufacturing apparatus.

More specifically, first, in the kneading step, each component of the above-mentioned toner particles is melt-kneaded to prepare a kneaded product. The mixing of the components can be performed using various conventionally known mixing devices (for example, a double cone mixer, a V-type mixer, a tumbler mixer, a super mixer, a Henschel mixer, a Nauta mixer, a Mechano Hybrid ( Japan COKE Industry Co., Ltd.), etc.). In melt kneading, batch kneaders such as pressure kneaders, Banbury mixers, or continuous kneaders can be used. From the advantages of continuous production, single-screw or twin-screw extruders have become mainstream. For example, KTK-type twin-screw extruder (manufactured by Kobe Steel Co., Ltd.), TEM-type twin-screw extruder (manufactured by Toshiba Machinery Co., Ltd.), PCM kneader (manufactured by Ikegai Co., Ltd.), A twin-screw extruder (manufactured by KCK Corporation), Ko-Kneader (manufactured by BUSS Corporation), Kneadex (manufactured by Nippon Coke Industries, Ltd.), and the like. In addition, as a toner material, the master batch containing the said binder resin and a coloring agent can be used.

Then, the kneaded product is cooled, and the cooled kneaded product is then pulverized (for example, coarsely pulverized with a crusher, hammer mill, Feather, etc., and then further pulverized with a Kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), for example) , Super rotor (manufactured by Nisshin Engineering Co., Ltd.), turbo mixer (manufactured by Freund Turbo Co., Ltd., finely pulverized by a jet-type pulverizer). The powder (pulverized product) obtained by the pulverization step is classified (for example, Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.) of inertial classification method, Turbo Plex (manufactured by Hosokawa Micron Co., Ltd.) of centrifugal force classification method), TSP Separator (manufactured by Hosokawa Micron Co., Ltd.), Faculty (manufactured by Hosokawa Micron Co., Ltd.), or a classifier or a sieving machine is used for classification). The volume median particle diameter (D50) of the pulverized and classified toner particles is preferably 4 to 10 μm. It should be noted that, in this embodiment, the volume median diameter (D50) is also referred to as the volume-based median diameter, which means that the total volume of particles with diameters smaller than this value and the volume total of particles with diameters larger than this value are The value of each occupied 50% of the total volume of the whole. The volume median particle diameter (D50) can be calculated by performing particle size distribution measurement. As a particle size distribution measuring apparatus, "Multisizer3" by Beckman Coulter can be mentioned.

As described above, the toner manufacturing method of the present embodiment does not require special equipment, and the toner can be manufactured using the same equipment as the conventional equipment. As described above, the obtained toner can achieve both excellent low-temperature fixability and storage stability. Therefore, according to the present manufacturing method, the cost increase of the toner can be prevented.

One embodiment of the present invention has been described above. The present invention is not particularly limited to the above-described embodiments. In addition, the said embodiment mainly demonstrates the invention which has the following structure.

(1) A toner for developing electrostatic images, comprising toner particles and an external additive, the toner particles comprising a binder resin containing a crystalline polyester resin, a colorant, and a release agent, the above The crystalline polyester resin contains sebacic acid as an acid component and 1,10-decanediol as an alcohol component, has a mass average molecular weight of 3,000 to 5,000, and is contained in the toner particles in an amount of 5 to 10% by mass.

According to this configuration, the obtained toner for developing electrostatic images can achieve both low-temperature fixability and storage stability.

(2) The toner for developing electrostatic images according to (1), wherein the crystalline polyester resin has a melting point of 70 to 76°C.

According to this configuration, the low-temperature fixability of the electrostatic image developing toner becomes good.

(3) The toner for developing electrostatic images according to (1) or (2), wherein the binder resin contains an amorphous resin, and the amorphous resin has a mass average molecular weight of 4,000 to 150,000, softens The point is 90 to 125°C.

According to this configuration, the toner for developing electrostatic images can achieve both excellent low-temperature fixability and storage stability.

(4) The electrostatic image developing toner according to any one of (1) to (3), which further contains a resin-type charge adjuster.

According to this configuration, the electrostatic image developing toner is more excellent in chargeability.

(5) A method for producing a toner for developing an electrostatic image, which is the method for producing a toner for developing an electrostatic image according to any one of (1) to (4), which comprises performing kneading after kneading. A process of cooling and solidifying, and then pulverizing and classifying to produce.

According to this configuration, the obtained toner for developing electrostatic images can achieve both low-temperature fixability and storage stability. In addition, the electrostatic image developing toner can be manufactured using the same equipment as the existing equipment. Therefore, according to the present manufacturing method, the cost increase of the toner can be prevented.

Example

Hereinafter, the present invention will be more specifically described by way of examples. The present invention is not limited by these Examples. In addition, unless it is specifically limited, "%" means "mass %", "part" means "mass part".

The raw materials used and the production method are shown below.

<Binder resin>

·Crystalline polyester resin

Crystalline polyester resin 1: polyester of sebacic acid and 1,10-decanediol. The mass average molecular weight is 3000 and the melting point is 74°C.

Crystalline polyester resin 2: polyester of sebacic acid and 1,10-decanediol. The mass average molecular weight is 5000 and the melting point is 74°C.

Crystalline polyester resin 3: polyester of sebacic acid and 1,10-decanediol. The mass average molecular weight is 5000 and the melting point is 75°C.

Crystalline polyester resin 4: polyester of sebacic acid and 1,6-hexanediol. The mass average molecular weight is 2600 and the melting point is 66°C.

Crystalline polyester resin 5: polyester of sebacic acid and 1,6-hexanediol. The mass average molecular weight is 5000 and the melting point is 67°C.

Crystalline polyester resin 6: polyester of sebacic acid and 1,6-hexanediol. The mass average molecular weight is 10000 and the melting point is 69°C.

Crystalline polyester resin 7: polyester of sebacic acid and 1,10-decanediol. The mass average molecular weight is 10000 and the melting point is 74°C.

Crystalline polyester resin 8: polyester of 1,12-dodecanedioic acid and 1,6-hexanediol. The mass average molecular weight is 3500, and the melting point is 71 °C.

Crystalline polyester resin 9: polyester of 1,12-dodecanedioic acid and 1,10-decanediol. The mass average molecular weight is 3000 and the melting point is 78°C.

・Amorphous binder resin used in combination

Amorphous binder 1: commercially available non-crystalline polyester resin (Tg 64°C, molecular weight 5500)

Amorphous binder 2: commercially available non-crystalline polyester resin (Tg 65°C, molecular weight 110,000)

＜Charge regulator＞

Brand name Copy Charge N5P-01 (manufactured by Clariant Chemicals)

＜Colorant＞

carbon black

＜Mold release agent＞

Release agent 1: fatty acid ester wax (melting point 69°C)

Release Agent 2: Hydrocarbon Wax

＜External Additives＞

External additive 1: Silica particles surface-treated with silicone oil (particle size: 22 nm)

External additive 2: Silica particles surface-treated with dimethyldichlorosilane (particle size: 12 nm)

External additive 3: titanium oxide particles (particle diameter: 14 nm) surface-treated with alkylsilane

<Examples 1 to 4, Comparative Examples 1 to 14>

(Preparation of Toner)

Crystalline polyester resin, commercially available polyester resin (Tg 64°C, molecular weight 5500, amorphous), commercially available polyester resin (Tg 65°C, Molecular weight 110,000, amorphous), fatty acid ester wax (melting point 69°C), hydrocarbon wax, charge control agent, and carbon black were mixed with a Henschel mixer, and then melt-kneaded with a twin-screw kneader. The obtained kneaded product was coarsely pulverized with Rotoplex, finely pulverized with a jet mill, and classified with an air classifier to obtain toner mother particles having a charged volume average particle diameter of 6.5 μm. With respect to 100 parts by mass of the toner base particles, 1.0% of silica particles (particle size: 22 nm) surface-treated with silicone oil and 0.5% of silica particles surface-treated with dimethyldichlorosilane were added Silicon particles (particle size: 12 nm) and 0.5% titanium oxide particles (particle size: 14 nm) surface-treated with alkylsilane were stirred with a Henschel mixer for 10 minutes to obtain toners of Examples and Comparative Examples.

【Table 1】

Table 1

For the toners of Examples and Comparative Examples obtained above, printed matter was produced under the following conditions, and the fixability, mold releasability, and storage stability were evaluated. The results are shown in Table 1.

<Evaluation of Fixing Ratio>

Using a non-magnetic two-component type negatively charged type printer for evaluation, a solid image was printed on plain paper (80 g/m ² ) in an environment of temperature 25° C. and humidity 50%, using Gakushin A rubbing fastness tester (NR-100 manufactured by Daiei Science & Technology Co., Ltd.) was used to perform a rubbing test on the above-mentioned full-print image under the following conditions. The image density before and after rubbing was measured using a reflection densitometer (manufactured by Macbeth), and the fixing ratio was calculated by the following formula.

Friction surface: Nonwoven fabric (trade name COTTON PADS, manufactured by Honeylon Co., Ltd.)

Load: 500g

Reciprocating times: 5 times

Horizontal reciprocating distance: 10cm

Fixing ratio (%): (image density after rubbing/image density before rubbing)×100

○: The fixing rate is 85% or more.

Δ: The fixing ratio is 80% or more and less than 85%.

×: The fixing rate is less than 80%.

<Evaluation of Fixability of Paper Edges (N/N Environment)>

Using a non-magnetic two-component type negatively charged type printer for evaluation, 10 full-print images with 100% coverage were continuously printed in an environment of a temperature of 25° C. and a humidity of 50%.

○: No peeling occurred due to scratching the image in all parts from the center part to the edge part of the paper.

Δ: Only the edge of the sheet was peeled due to scratching the image.

×: Peeling occurred due to scratching of the image in both the center portion and the edge portion of the paper.

<Evaluation of paper edge fixability (L/L environment)>

Using a non-magnetic two-component type negatively charged type printer for evaluation, 10 full-print images with 100% coverage were continuously printed in an environment of a temperature of 10° C. and a humidity of 20%.

○: No peeling occurred due to scratching the image in all parts from the center part to the edge part of the paper.

Δ: Only the edge of the sheet was peeled due to scratching the image.

×: Peeling occurred due to scratching of the image in both the center portion and the edge portion of the paper.

<Evaluation of releasability>

Using a non-magnetic two-component type negatively charged type printer for evaluation, a full-print image with 100% coverage was printed on plain paper (64 g/m2), and it was wound around a fixing device to evaluate the peeling marks of the fixing roller, offset printing The occurrence of dirt.

○: It was wound around the fixing device, and there were no peeling marks or offset stains of the fixing roller.

×: It was wound around the fixing device, and any of peeling marks of the fixing roller and offset stains occurred.

<Storage stability at 50°C/8 hours>

20 g of the toner was put into a sealed plastic container and stored at 50° C. for 8 hours, and then evaluated with a powder tester (manufactured by Hosokawa Micron Co., Ltd.). The sieves of sieve A (mesh: 355 μm), sieve B (mesh: 250 μm), and sieve C (mesh: 150 μm) were stacked in this order from the top, and 20 g of toner was put into sieve A and vibrated at an amplitude of 1 mm for 30 seconds. , and measure the weight of the remaining toner.

The aggregation degree calculated as follows was evaluated.

Aggregation %: (Toner remaining on sieve A (g) + Toner remaining on sieve B (g) × 0.6 + Toner remaining on sieve A (g) × 0.2)/20 × 100

○: The degree of aggregation is less than 10%.

Δ: Aggregation degree is 10% or more and less than 20%.

×: The aggregation degree is 20% or more.

<Storage stability 55°C/8 hours>

20 g of the toner was put into a sealed plastic container and stored at 55° C. for 8 hours, and then evaluated with a powder tester (manufactured by Hosokawa Micron Co., Ltd.). The sieves of sieve A (mesh: 355 μm), sieve B (mesh: 250 μm), and sieve C (mesh: 150 μm) were stacked in this order from the top. The weight of the remaining toner is measured.

The aggregation degree calculated as follows was evaluated.

Aggregation %: (Toner remaining on sieve A (g) + Toner remaining on sieve B (g) × 0.6 + Toner remaining on sieve A (g) × 0.2)/20 × 100

○: The degree of aggregation is less than 10%.

Δ: Aggregation degree is 10% or more and less than 20%.

×: The aggregation degree is 20% or more.

As described in Table 1, the toners of Examples 1 to 4 were excellent in fixability, offset printing, and storage stability. On the other hand, the toners of Comparative Examples 1 to 8 using a crystalline polyester containing an alcohol component with a small number of carbon atoms did not achieve both fixability and storage stability. The toner of Comparative Example 9 using a crystalline polyester having a large molecular weight had poor fixability at the edge of the sheet under an environment of a temperature of 10° C. and a humidity of 20%. The toners of Comparative Examples 10 and 11 using a crystalline polyester containing a carboxylic acid component with a large carbon number and an alcohol component with a small carbon number did not achieve both fixability and storage stability. In addition, the toner of Comparative Example 12 using a crystalline polyester containing a carboxylic acid component with a large carbon number and an alcohol component with a large carbon number was poor in the paper edge fixability in an environment of a temperature of 10° C. and a humidity of 20%. In addition, the toner of Comparative Example 13 with a small content of the crystalline polyester resin of the present invention was poor in fixability, and the toner of Comparative Example 14 with a large content of the crystalline polyester resin was poor in storage stability.

Claims (5)

1. A toner for developing electrostatic images, comprising toner particles and an external additive, The toner particles contain a binder resin containing a crystalline polyester resin, a colorant, and a release agent, The crystalline polyester resin: Contains sebacic acid as an acid component and 1,10-decanediol as an alcohol component, The mass average molecular weight is 3000～5000, 5 to 10 mass % is contained in the toner particles. 2. The electrostatic image developing toner according to claim 1, wherein The melting point of the crystalline polyester resin is 70 to 76°C. 3. The electrostatic image developing toner according to claim 1 or 2, wherein The binder resin contains an amorphous resin, The amorphous resin has a mass average molecular weight of 4,000 to 150,000 and a softening point of 90 to 125°C. 4. The electrostatic image developing toner according to any one of claims 1 to 3, further comprising a resin-type charge adjuster. 5. A method for producing a toner for developing an electrostatic image, which is the method for producing a toner for developing an electrostatic image according to any one of claims 1 to 4, It includes the steps of cooling and solidifying after kneading, and then pulverizing and classifying to manufacture.