JPS5931066B2 - Manufacturing method of pressure fixable magnetic microcapsule toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrostatographic toner, and more particularly to a method for producing a magnetic microcapsule toner that can be fixed by pressure.

The development methods for dry electrophotography are generally the cascade method,
A magnetic brush method is used.

In each of these methods, carrier particles such as glass beads or iron powder are mixed with toner particles to form a developer, the toner particles are charged by frictional charging, and this is brought into contact with an electrostatic latent image to visualize it. However, toner particles (finely pulverized thermoplastic resin with colorant uniformly dispersed in them) further become pulverized during frictional charging with carrier particles, causing contamination inside and outside the copying machine due to scattering of toner particles. At the same time, the carrier particles deteriorate and the image quality deteriorates, necessitating early replacement of the developer. Furthermore, in order to fix the powder images obtained with these toners, it is necessary to heat and melt the toner, and to do so, it is necessary to raise the temperature of the fixing device to the softening point of the toner. It takes a long time and has disadvantages such as consuming a considerable amount of power to maintain the predetermined temperature. On the other hand, in recent years, in order to omit the mixing step of toner particles and carrier particles, a method of developing with a magnetic roller has been developed (e.g., Japanese Patent Laid-Open No. 49-4532), and research has also been conducted on developers for this method. ing.

This type of developer consists of a toner which itself contains carrier. In addition, the fixing method after development has been simplified, and the conventional heat fixing method, which requires a lot of energy, is being replaced by a low-energy pressure fixing method. Machines are also commercially available. The requirements for the pressure-fixable magnetic toner used in such copying machines include magnetic properties that allow it to easily adhere to the roller surface due to the magnetic field of the magnetic roller, and the ability to resist magnetic force and become static due to its own electric charge or electric field. It is necessary to have electrical properties that are easily attracted to an electrostatic latent image, properties as carrier particles, and therefore sufficient fluidity and pressure fixing properties that allow fixing with as low a pressure as possible.

However, it is extremely difficult to obtain a toner that satisfies all of these requirements.
The pressure-fixable magnetic toner described in the above issue has poor fluidity, so it is necessary to add a fluidity-imparting agent such as hydrophobic silica, which also inhibits fixability and reduces the pressure required for fixing. It is extremely large at 300 to 400 pounds/inch, and cannot be called a complete product for practical use. The present invention eliminates the above-mentioned drawbacks and provides a practical pressure-fixable magnetic toner that has excellent fluidity and can be fixed with a low pressure.

The basic manufacturing method of the pressure-fixable magnetic microcapsule toner according to the present invention is the following methods 1) and 2).

First, method 1) involves emulsifying and dispersing a polymerizable monomer or its non-aqueous solution that can become a soft polymer through polymerization or crosslinking reaction into an aqueous solution of a hydrophilic film-forming polymer substance, and emulsified droplets (mainly monomer or its non-aqueous solution). ) is encapsulated (mainly with the above-mentioned polymeric substance), then a) the encapsulated liquid is polymerized or crosslinked by a method such as heating and taken out, or b) the encapsulated liquid is spray-dried and taken out as a powder. , carry out a polymerization or crosslinking reaction. In this case, the colorant and magnetic particles are added separately or in a mixture to the monomer (or its non-aqueous solution) and/or the aqueous solution of the polymeric substance. Alternatively, as method 2), the capsule dispersion obtained by method 1)-a) is mixed with an aqueous suspension or latex of a hard resin, and this is spray-dried to obtain a double-encapsulated dry powder; Alternatively, the method 1)-a) may be carried out except for the polymerization reaction, and the polymerization reaction may be carried out at the same time or after spray drying in the same manner.

In this case, the colorant and magnetic particles are added separately or in a mixture as in 1) into the monomer (or its non-aqueous solution) and/or into the aqueous solution of the polymeric substance and/or into the aqueous suspension of the hard resin. do.

It has been found that the step of polymerizing the monomer after encapsulating the monomer or its non-aqueous solution as described above is preferable in terms of controlling the particle size and improving fixing properties.

The monomers used in the present invention include 2 monomers in the linear chain or in the side chain.
Anything that has a double bond and can be polymerized into a soft polymer by reaction is effective, such as styrene, vinyl chloride,
Vinyl monomers such as vinyl acetate and vinyl alkyl ether, acrylic monomers such as acrylic acid, methacrylic acid and their esters or amides, unsaturated fatty acids such as oleic acid, linoleic acid and linolenic acid, saturated fatty acids and polyhydric alcohols. Suitable drying oils are suitable, and these may be used alone or in combination.

Furthermore, a polymerization initiator, a reaction accelerator, etc. are used in combination with these monomers. As the non-aqueous solvent, aliphatic or aromatic hydrocarbons, halogenated hydrocarbons, etc. are used.

Examples of monomer encapsulation methods include complex coacervation, simple coacervation, salt coacervation, and polymer insolubilization methods by PH change, temperature change, solvent substitution, or solvent removal. Any method that encapsulates a hydrophobic substance in an aqueous medium can be used, such as a separation method, an interfacial polymerization method, and a 10-SltU polymerization method.

Further, as the polymerization method, conventional methods such as heating, ion, water, electron beam, radiation irradiation, etc. are employed. Hydrophilic film-forming polymeric substances include gelatin, amhumin, casein, gum arabic, sodium alginate, carboxymethyl cellulose, hydroxyethyl cellulose, ethylene-sodium maleic anhydride copolymer, vinyl methyl ether-maleic anhydride copolymer, etc. Zwitterionic polymeric materials and polyanionic polymeric materials are used. Hard resins include vinyl resins such as polycarbonate, polyester, polyamide, polyether, polyolefin, polystyrene, polyvinyl acetate, and polyvinyl chloride;
Copolymer of styrene and acrylic acid or its ester,
Copolymers of styrene and methacrylic acid or its esters, copolymers of styrene and vinyl esters or vinyl ethers, copolymers of styrene and acrylonitrile, copolymers of styrene and acrylamide, styrene and ethylenically unsaturated monomers Copolymers of olefins, copolymers of styrene and vinyl halides, copolymers of styrene and alpha-methylene fatty acid monocarboxylic acid esters are used in the form of aqueous suspensions or latexes.
Pigments or dyes such as carbon black can be used as coloring agents.
In addition, magnetic particles include metal powders such as iron, nickel, and cobalt, and alloy powders thereof, and fine particles such as magnetic iron oxide, carbonyl iron, and ferrite (particle size is preferably 1 μ or less).
or a mixture thereof.

Example 1 In 250ml of 0.5wt% polyvinyl alcohol aqueous solution, 13.49% of Rariul methacrylate, 0.129% of benzoyl peroxide, 1.339% of terephthaloyl chloride, and magnetic iron powder (manufactured by Toda Kogyo Co., Ltd. M=32) 89 1.649 hexamethylene diamine and 0.19 sodium bicarbonate were dissolved in this liquid and 20 ml was mixed and uniformly emulsified and dispersed using a homomixer. The magnetic iron powder and lauryl methacrylate monomer were encapsulated with a polyamide film, and heating was continued for 8 hours at 90 to 95°C to polymerize the lauryl methacrylate contained therein.

Next, an aqueous suspension of polyvinyl acetate (A-522 manufactured by Daicel Corporation, solid content 50%) 119 and water-dispersible carbon black (Coloidex Boiled 5 manufactured by Columbia Carbon Co., USA) were uniformly dispersed in this capsule dispersion. After making capsule slurry, using a Niro atomizer, the inlet temperature was 135°C, the outlet temperature was 85°C, and the spray pressure (as compressor pressure) was 5.6 kg/CTi.
The mixture was spray-dried under the following conditions to obtain a pressure-fixable magnetic toner encapsulated in two types, each containing magnetic particles in the core and carbon black in the wall. Example 2 A pressure fixable magnetic microcapsule toner was obtained in the same manner as in Example 1 except that a mixture of lauryl methacrylate/styrene-8/2 (molar ratio) was used instead of lauryl methacrylate.

Example 3 A pressure fixable magnetic microcapsule toner was obtained in the same manner as in Example 1 except that a mixture of lauryl methacrylate/butyl acrylate = 6/4 (molar ratio) was used instead of lauryl methacrylate.

Example 4 Manganese naphthenate (metal content 8) in 109 toluene
wt%) 0.79, cobalt naphthenate (metal content 6w
t(:Ff)) 0.49 and an oil-soluble dye (Oil Black HBB manufactured by Orient Chemical Co., Ltd.) 0.19 were dissolved,
In addition to this, 13.49 g of linseed oil, 1.33 g of trimesylic acid chloride and magnetic particles (VacuumMetall
surgicalCO. A fine nickel-iron-cobalt alloy powder) manufactured by Co., Ltd. was mixed and uniformly dispersed to form a core material.

This material was mixed with 250a prepared by dissolving 0.19 sodium pyrophosphate and 0.5g of polyvinyl alcohol.
Then, 20 ml of an aqueous solution in which 19 parts of sodium hydroxide and 1.64 parts of hexamethylene diamine were dissolved was dropped into the emulsion with stirring, and the core material was encapsulated with a polyamide film. Finally, this capsule dispersion was heated at 80°C for 5 hours to polymerize the linseed oil contained therein, and then a Niro atomizer was used at an inlet temperature of 135°C, an outlet temperature of 85°C, and a compressor pressure of 5.0 kg/CTii. A pressure fixable magnetic microcapsule toner containing magnetic particles and polymerized linseed oil was obtained by spray drying under the following conditions. Example 5 In Example 4, the mixture of manganese naphthenate and cobalt naphthenate was replaced with lead naphthenate (metal content 8 wt(f)
) A pressure fixable magnetic microcapsule toner was obtained in the same manner as above except in Example 19.

Example 6 Before spray drying in Example 4, an aqueous polystyrene suspension (DOw-201, manufactured by Tau Chemical Co., USA) 129 and water-dispersible carbon black (Colloidex/F65) 29 were further mixed into the capsule dispersion to ensure uniform dispersion. After making it into a liquid, use a Niro atomizer to lower the inlet temperature to 1.
35℃, outlet temperature 85℃, compressor pressure 5.6k
A pressure-fixable magnetic toner having double capsules was obtained by spray drying under the conditions of 9/d.

Example 7 275g of 37wt% formaldehyde aqueous solution and 10% of urea
The mixture of 09 was adjusted to pH 7.5 with 10wt01) ethanolamine aqueous solution and stirred at 70°C for about 2 hours to obtain a urea-formaldehyde initial condensate.

Next, this initial condensate was made into a 5 wt% aqueous solution, and the 250%
As in Example 1, lauryl methacrylate 13.
49. Emulsifying and dispersing 0.129% of benzoyl peroxide, adding citric acid while stirring to lower the pH to 3.5, and maintaining the temperature at 48±2°C for about 5 hours at 90°C. The reaction was carried out for 2 hours to polymerize the encapsulated and encapsulated lauryl methacrylate. Then, the aqueous suspension of polyvinyl acetate used in Example 1 209 and water-dispersible carbon black 1 were added to the resulting capsule dispersion.
After homogeneously dispersing g and magnetic iron powder 109 to form a colored capsule slurry, the slurry was spray-dried using a Niro atomizer under the same conditions as in Example 1, and the core contained lauryl methacrylate polymer, and the wall contained magnetic particles and carbon black. A double encapsulated pressure fixable magnetic toner was obtained. Example
8 3.5 wt% gum arabic aqueous solution 1509 to 1N Na0
H'('PHlO), add 0.79 azobisisobutyronitrile, 8.1 lauryl methacrylate to this solution.
9 and water-dispersible carbon black 19 to uniformly disperse the dispersion, and then a 5 wt% gelatin aqueous solution 1009 of PHLO was mixed with this dispersion, stirred while maintaining the temperature at 50±1°C, and heated with acetic acid for about 2 hours. gelatin containing carbon black around lauryl methacrylate monomer emulsified droplets by lowering the pH to 4.8 by dropping
The gum arabic mixed thick phase was phase separated.

Furthermore, 130 ml of water at 5 min C was added to this system, and stirred for 30 min while maintaining this temperature.
A 10w1% aqueous solution 309 of AN-119) was added, and then 3ml of a 37w1 (!) formaldehyde aqueous solution was added.

Claims (1)

[Scope of Claims] 1. A polymerizable monomer capable of forming a soft polymer through polymerization or crosslinking reaction, or a non-aqueous solution thereof, is emulsified and dispersed in an aqueous solution of a hydrophilic film-forming polymeric substance, and emulsified droplets are encapsulated with the polymeric substance. coating, and then a) polymerizing or crosslinking the monomers in the capsules in this encapsulating liquid, or b) spray drying the encapsulating liquid and polymerizing or crosslinking the monomers in the capsules, using a coloring agent. A method for producing a pressure-fixable magnetic microcapsule toner, which comprises adding magnetic particles and magnetic particles separately or in a mixture to the monomer or its non-aqueous solution and/or the aqueous solution of the polymeric substance. 2. Emulsifying and dispersing a polymerizable monomer capable of forming a soft polymer through polymerization or crosslinking reaction or a non-aqueous solution thereof in an aqueous solution of a hydrophilic film-forming polymeric substance, encapsulating the emulsified droplets with the polymeric substance, and then a) After polymerizing or crosslinking the monomers in the capsules in this encapsulation liquid, the resulting Spcel dispersion was mixed with an aqueous suspension of hard resin, and this was spray-dried to form a 2-layer mixture with the hard resin.
or b) mixing the pre-polymerized encapsulation liquid with an aqueous suspension of hard resin and spray drying it to double gravity encapsulation with the hard resin, simultaneously or after the monomers in the double capsule. When performing a polymerization or crosslinking reaction, the colorant and magnetic particles are added separately or in a mixture to the monomer or its non-aqueous solution, and/or the aqueous solution of the polymeric substance and/or the aqueous suspension of the hard resin. A method for producing a pressure-fixable magnetic microcapsule toner characterized by: