JPH0422269B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a capsule toner used for developing latent images in electrophotography, electrostatic printing, magnetic printing, and the like. Conventionally, as an electrophotographic method, U.S. Patent No. 2297691
Specification of No. 42-23910 and Special Publication No. 1973
Many methods are known, as described in Japanese Patent No. 24748, etc., but in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the The latent image is developed using toner, and after the toner image is transferred to a transfer material such as paper as necessary, it is fixed by heat, pressure, solvent vapor, etc. to obtain a copy. Therefore, U.S. Patent No. 3269626, Japanese Patent Application Publication No. 1973
102624, etc., the method of fixing toner under pressure is energy saving, non-polluting, allows copying without waiting time when the copier is turned on, has no risk of burning copies, and is fast. It has many advantages such as being able to be fixed and having a simple fixing device. However, in such conventional pressure fixing methods, satisfactory toner fixing performance cannot be obtained unless special treatment is applied to the image support, and the fixing pressure is 200%.
The drawback was that it required an extremely high pressure of ~300Kg/cm ² . Furthermore, in conventional pressure-fixed toners, it is generally essential to use soft materials, and as a result, the toner lacks storage stability, causing toner particles to fuse and form blocks, and forming a film on the drum surface. It has disadvantages such as carrier contamination, fusing roller offset generation, etc. Furthermore, non-polar soft materials such as waxes that are commonly used as such soft materials generally cannot be uniformly dispersed when colorants and magnetic materials are added therein, and as a result, exhibit development characteristics with extremely poor image quality. . In order to solve the above-mentioned drawbacks, microcapsule toner, which is considered to be an ideal toner, has been proposed in recent years. This microcapsule toner is produced by first forming core particles that impart fixability, and then covering the core particles with a hard shell material that contributes to developability. However, there are still many problems with this method. For example, 1. The adhesion between the particles and the capsule shell is insufficient, and when used as a pressure-fixable microcapsule toner, the durability deteriorates significantly. 2. During encapsulation, the core particles are encapsulated while remaining agglomerated, so coarse particles are likely to be formed. 3. During encapsulation, independent particles consisting only of core particles or only shell material are formed, resulting in sleeve contamination, reduction in image density, etc. The present invention provides a capsule toner that overcomes these drawbacks. Furthermore, another object of the present invention is to provide a capsule toner that can be developed at high speed with low pressure. Furthermore, another object of the present invention is to provide a true spherical capsule toner having uniform particle diameters. Still another object of the present invention is to provide a capsule toner that has good adhesion between a core material and a shell material and stable triboelectric charging characteristics. Yet another object of the present invention is to provide capsule toners with excellent physical and chemical uniformity. Specifically, the present invention provides the following formula [In the formula, R ₂ and R ₃ represent hydrogen, an alkyl group, an allyl group, or an alkylaryl group, and R ₄ is -
It represents _CH2- , -O- or -NH-, and n represents an integer. ] The present invention relates to a capsule toner characterized by having core particles containing 5 to 40% by weight of an α-olefin derivative having the structure shown as an essential component, and a shell material covering the core particles. By incorporating the α-olefin and the derivative into the soft core particles, a capsule toner that is viscoelastically effective, that is, exhibits remarkable fluidity with a small stress, and particularly has good pressure fixability can be obtained. Furthermore, if a coloring agent and/or a magnetic material are added to the core particles as necessary, the α-olefin derivative, which is a feature of the present invention, exhibits good interaction with the coloring agent and/or magnetic material, and the coloring agent and/or the magnetic material are added to the core particles. It has the feature of uniformly dispersing the particles. The molecular weight of α-olefin derivatives is 100 to 35,000.
is preferred. Specifically, the compound groups shown in Table [] are used. The compound is added in an amount ranging from 5 to 40% by weight based on the total toner weight. At this time, if the amount added is less than 5% by weight, in the core particle generation process,
Not only is it difficult to obtain core particles with uniform particle diameters, but it also hinders uniform dispersion of colorants and/or magnetic substances added when necessary. On the other hand, if the amount added is more than 40% by weight, problems will arise in fixing properties as core particles for pressure fixing.

【table】

[Table] The α-olefin and/or α-olefin derivative described above may be used in appropriate combination with other adhesive compounds, if necessary. Specific examples include Karva wax, Candeli wax, rice wax, lanolin, jojoba wax, montanic acid ester wax, Japan wax, wax wax, paraffin wax, micro crystal wax, halogenated paraffin wax, etc. Waxes; fatty acids such as stearic acid and palmitic acid; oleic acid amide, stearic acid amide, palmitic acid amide, N-hydroxyethyl-hydroxystearamide, N-N'-ethylene-bis-stearamide, N,N'- Fatty acid amides such as ethylene-bis-ricinolamide and N,N'-ethylene-bis-hydroxystearylamide; fatty acid metal salts such as aluminum stearate, zinc stearate, barium stearate, magnesium stearate, and zinc palmitate. . In the present invention, the compounds to be used in combination are not necessarily limited to the above-mentioned compounds, and can be used in arbitrary combination with other polymeric compounds if necessary. Any suitable hard material can be used as the shell material for the capsule toner used in the present invention. The shell material may be a homopolymer or a copolymer of two or more monomers. Specific examples include polyvinyl acetate, styrene-butadiene copolymer, polystyrene, polyacrylic acid, polycarbonate, polyester, polyamide, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-vinyl ester copolymer, etc. Polymer, styrene-vinyl ether copolymer, styrene-acrylonitrile copolymer, styrene-methacrylonitrile copolymer, styrene-acrylamide copolymer, styrene-α-methylene fatty acid monoester copolymer, styrene-vinylidene halide There are copolymers, etc. The amount of these shell materials added is based on the total toner weight.
It is used in a range of 0.1 to 20% by weight, preferably 1 to 10% by weight. If the amount added is less than 0.1% by weight, the surface of the core material will not be sufficiently coated with the shell material, and in some cases, a defective film will occur, resulting in significantly poor durability as a toner. On the other hand, when the amount added was 20% by weight or more, the toner could not be sufficiently fixed on the support when the fixing pressure was low. Furthermore, in order to use the toner of the present invention as a magnetic toner, it may contain magnetic powder, which is
It may be contained in either or both of the core material and the coating. Examples of such magnetic powder include powders of ferromagnetic metals such as iron, cobalt, and nickel, or compounds such as magnetite, hematite, and ferrite, which are materials that are magnetized when placed in a magnetic field. The content of this magnetic powder is 15 to 70% by weight based on the weight of the toner. Additionally, additives can be added to the toner of the present invention for various purposes. Such additives include metal complexes, charge control agents such as nigrosine, lubricating compounds such as polytetrafluoroethylene, and plasticizers such as dicyclohexyl phthalate. The additive may be contained in either or both the core material and the coating. Furthermore, the toner of the present invention is mixed with carrier powder such as iron powder, glass beads, nickel powder, ferrite powder, etc., if necessary, and used as a developer for electrical latent images. It can also be used in combination with fine hydrophobic colloidal silica powder for the purpose of improving the free-flowing properties of the powder, and fine particles of an abrasive such as cerium oxide to prevent toner sticking. Methods for encapsulation using the above composition include a method in which core particles are granulated in advance and then encapsulated in stages, and a method in which core particle formation and encapsulation are performed simultaneously.
Specifically, various known encapsulation techniques can be used. For example, spray drying method,
Interfacial polymerization method, coacervation method, phase separation method,
U.S. Patent No. 3338991 including in-situ polymerization method,
The methods described in Specification No. 3326848, Specification No. 3502582, etc. can be used. A typical capsule forming technique is disclosed by MW Raney as the "microcapsule coating technique."
A preferred method for producing the toner of the present invention is to spray-dry or emulsify and disperse a core material that has been heated and melted in advance in an aqueous system, and then to apply at least one type of fine particles containing a shell material to the core particles. Disperse in solvent. Almost simultaneously, a solvent that acts as a poor solvent for the shell material is gradually added to the cored material-containing dispersion to cause the shell material to adhere around the core material, thereby obtaining a microcapsule toner encapsulated by the shell material. There is a way. Furthermore, as another preferable manufacturing method, when the surface of the core material is coated with a shell material film, for example, core particles are dispersed in a shell material resin solution, and the resulting dispersion is spray-dried using a spray dryer. Also used is a method in which a resin film is formed on the surface of the core material by removing the solvent. Example 1 Paraffin wax (product name Paraffin 155-
Nippon Seiro Co., Ltd.) 70 parts by weight α-olefin-maleic anhydride copolymer (Compound 5 in Table ()) 15 parts by weight Ethylene-vinyl acetate copolymer 15 parts by weight Magnetite 60 parts by weight were prepared in advance at 120°C. The mixture was heated and kneaded for 1 hour using a homomixer. 30 g of this molten mixture was added to a dispersion medium heated to 90°C consisting of 500 parts by weight of H ₂ O and 1 part by weight of an anionic surfactant, and the rotation speed was 5000 rpm using an Ajihomo mixer manufactured by Tokushu Kika Kogyo Co., Ltd.
Stirring was continued for 2 minutes at . The obtained core particles are
Measurement using a Coulter counter showed a sharp particle size distribution with a volume average particle diameter of 12.5 μm and a standard deviation of 3.5. 30 g of the obtained core particles were further mixed with 0.7 parts by weight of polystyrene-dimethylamino methacrylate copolymer polymethyl methacrylate. It was dispersed in a solution consisting of 1 part by weight of DMA and 50 parts by weight using an Ajihomo mixer. Next, by gradually adding 50 c.c. of H ₂ O, it was possible to completely coat the core particles with the shell material. After further filtering and drying, the particles obtained had a volume average particle diameter of 12.8 μm, and the standard deviation thereof was 2.3. Example 2 As a core material, 70 parts by weight of paraffin wax, 15 parts by weight of α-olefin-maleic anhydride copolymer (compound 7 in Table ()), 15 parts by weight of ethylene-vinyl acetate copolymer, and 60 parts by weight of magnetite were used. It was carried out in the same manner as in Example 1 except for this. Example 3 Parafine wax 70 parts by weight α-olefin-maleic anhydride copolymer (Compound 5 in Table ()) 20 parts by weight Ethylene-vinyl acetate copolymer 15 parts by weight Magnetite 60 parts by weight were homogenized at 120°C. The mixture was heated and kneaded for 1 hour using a mixer. 30 g of this molten mixture was added to a dispersion medium heated to 90° C. containing 500 parts by weight of H ₂ O and 1 part by weight of an anionic surfactant, and stirring was continued for 2 minutes at 5000 rpm using an Ajihomo mixer. The obtained core particles were further dispersed in a solution consisting of 0.7 parts by weight of polystyrene-dimethylamino methacrylate copolymer, 1.0 parts by weight of methyl methacrylate, and 50 parts by weight of methyl ethyl ketone, and then microencapsulated using a spray dryer. Ta. When an electrostatic latent image was developed using the toner obtained as described above and fixed under pressure at a linear pressure of 10 kg/cm, the results shown in the table below were obtained.

[Table] As explained above, by adding α-olefin or/and α-olefin derivative as an essential component to the core material, microcapsules with improved durability can be formed that can be used without classification. You can get toner,
Excellent advantages such as a microcapsule toner with excellent resolution can be obtained.

Claims (1)

[Claims] 1. The following formula [In the formula, R ₂ and R ₃ represent hydrogen, an alkyl group, an allyl group, or an alkylaryl group, and R ₄ is -
It represents _CH2- , -O- or -NH-, and n represents an integer. ] A capsule toner comprising core particles containing 5 to 40% by weight of an α-olefin derivative having the structure shown as an essential component, and a shell material covering the core particles.