JPS6336500B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing developer powder used in electrophotography, electrostatic recording, magnetic recording, 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 developer powder (toner), the toner image is transferred to a transfer material such as paper as required, and then fixed by heat, pressure, solvent vapor, etc. to obtain a copy. Various methods are also known for visualizing electrical latent images using toner. For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. Many developing methods are known, such as the developing line method. As toners used in these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. Furthermore, it is also known to use fine developing powder to which a third substance is added for various purposes. Conventional developer powder contains an expensive charge control agent in order to impart a charge through frictional charging, which is one of the causes of increased costs. Furthermore, in the case of a one-component developer in which a magnetic material is contained in the developer powder, charging properties become unstable due to the magnetic material being partially exposed on the surface. Furthermore, there is a drawback that the charging property tends to change due to changes in the environment, particularly under high temperature and high humidity conditions. An object of the present invention is to provide a method for producing a developing powder with good triboelectric chargeability and stable chargeability. Another object is to provide a method for producing developing powder with low production cost. Another object of the present invention is to provide a method for producing a developing powder whose triboelectric charging properties are stable even when a magnetic substance is contained in the developing powder. Specifically, the present invention provides salicylic acid or a salicylic acid derivative represented by the following formula, [In the formula, R ₁ is H-,

[Formula] or C ₂ H ₅ −, R ₂ is

【formula】

【formula】

【formula】

【formula】

[Formula] or H ₂ N-CH ₂ -, and R ₃ and R ₄ represent H- or t-C ₄ H ₉ -. ] The present invention relates to a method for producing developer powder, which comprises a step of heating and kneading a developer powder material containing an inorganic first transition metal compound and a binder resin. Inorganic metal compounds applicable to the present invention include:
Inorganic materials such as oxides and chlorides of iron, cobalt, nickel, copper, zinc, chromium, manganese, titanium, vanadium, scandium, ruthenium, molybdenum, silver, rhodium, tungsten, ossium, aluminum, tin, lead, magnesium, etc. Metal compounds of various types can be used, and oxides and chlorides of first transition metals are particularly preferred. Salicylic acid and its derivatives applicable to the present invention include salicylic acid, tertiary butylsalicylic acid, 3.5.-ditertiarybutylsalicylic acid, acetylsalicylic acid, salicyloylsalicylic acid, phenyl salicylate, salicylamide, salicylanilide, salicylamine, ethoxybenzamide,
etc. can be used. The amount of salicylic acid or a salicylic acid derivative and an inorganic metal compound is 0.1 to 0.1 to 100 parts by weight of the binder resin in the developer powder material.
It is preferable to use 20 parts by weight (more preferably 0.5 to 10 parts by weight) and 1 to 100 parts by weight of the inorganic metal compound. In order to obtain a magnetic toner, a magnetic material may be contained in the developer powder. As the magnetic substance, ferromagnetic elements and compounds containing these can be used, such as iron such as magnetite, hematite, and ferrite, and compounds such as cobalt, nickel, and manganese. These magnetic substances can be used as the inorganic metal compound. In order to obtain an appropriately chargeable insulating toner (volume resistivity 10 ¹³ to 10 ¹⁶ Ωcm), the magnetic material may be contained in an amount of 45 to 100 parts by weight based on 100 parts by weight of the binder resin. The binder resin applicable to the toner of the present invention includes:
Monopolymers of styrene and its substituted products such as polystyrene, poly-P-chlorostyrene and polyvinyltoluene, styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene-
Vinyl toluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer,
Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene- α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer,
Styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile
Styrenic copolymers such as indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride,
polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide,
Epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. They can be used alone or in combination. In addition, a coloring agent, a fluidity improver, a charge control agent, etc. may be used as the developing powder material, if necessary. As a developing powder manufacturing method, known manufacturing methods can be applied. For example, there is a method in which developer powder materials are mixed, melted and kneaded while heating, and then finely pulverized to obtain developer powder. Example 1 Styrene-butyl methacrylate copolymer (copolymerization ratio 7:3) 100 parts by weight Magnetite 60 parts by weight 3.5-ditertiary butylsalicylic acid 5 parts by weight The above materials were premixed and heated at about 150°C using a mixing roll. After kneading and cooling, the obtained lumps were crushed and classified to obtain a toner for magnetic developer powder with an average particle size of 13 μm. 0.2% by weight of hydrophobic colloidal silica was externally added to this toner to prepare a developer. This will be used as a sample. On the other hand, a toner was prepared and used as a developer in exactly the same manner as above except that 3,5-ditertialbutylsalicylic acid was removed. This will be used as a comparison sample. The sample was copied 30,000 times using an NP-2000J (Canon copier). Clear images were obtained both initially and after 30,000 times. Furthermore, during the initial stage of copying, the charge amount of the toner was measured every 1000 sheets by the blow-off method after mixing with carrier, and it was -15 ± 1 μQ/g.
It only changed within the range of , and remained almost constant. Furthermore, even when the sample was tested under high temperature and high humidity conditions and low temperature and low humidity conditions, the images were almost the same as those at normal temperature and humidity. On the other hand, a similar test was conducted using a comparative sample.
Even under normal repatriation conditions, only vague images can be obtained.
As copying was repeated, the maximum image density also decreased, and the amount of charge on the toner was initially as low as -8 μQ/g. Furthermore, almost no images could be obtained under high temperature and high humidity conditions. Example 2 Styrene-butadiene copolymer (copolymerization ratio 6:
1) A developer was prepared and tested in the same manner as in Example 1, except that 100 parts by weight of magnetite, 60 parts by weight of salicyloylsalicylic acid, and 5 parts by weight were used. In this case as well, a clear and stable image was obtained. Example 3 Styrene-butyl methacrylate copolymer (copolymerization ratio 7:3) 100 parts by weight Carbon black 8 parts by weight Ferrous chloride 8 parts by weight 3.5-ditertiary butylsalicylic acid 4 parts by weight The above substances were premixed. After that, the mixture was kneaded with a mixing roll (kneading temperature: 150°C), and the solidified product obtained by cooling was pulverized to obtain a toner for two-component developer powder.
This toner is mixed with a carrier made of iron powder,
A two-component developer with a toner concentration of 10% by weight was created. This will be used as a sample. On the other hand, a toner was produced as a two-component developer in exactly the same manner as above, except that ferrous chloride was omitted. This will be used as a comparison sample. The sample was copied 10,000 times using an NP-5000 (Canon copier). Clear images were obtained both initially and after 10,000 times. Also, during this period, 1000
The amount of charge on the toner was measured for each sheet, and it was -8±
Although it varied within a range of 0.5 μQ/g, it remained almost constant. The sample was also tested under high temperature and high humidity conditions, but the image did not change compared to when it was at room temperature and humidity. However, when a comparative sample was tested, only unclear images were obtained even under normal conditions, and the amount of charge of the toner was as low as -2 μQ/g. Example 4 A magnetic developer powder was prepared and tested in the same manner as in Example 1, except that 100 parts by weight of styrene-butyl methacrylate copolymer (copolymerization ratio 7:3), 60 parts by weight of magnetite, and 6 parts by weight of salicylic acid were used. A clear image with stable image density and toner charge amount was obtained.

Claims (1)

[Claims] 1 Salicylic acid or a salicylic acid derivative represented by the following formula, [Wherein, R ₁ represents H-, [Formula] or C ₂ H ₅ -, R ₂ represents [Formula] [Formula] [Formula] [Formula] [Formula] or H ₂ N-CH ₂ - , R ₃ and R ₄ represent H- or t-C ₄ H ₉ -. ] A method for producing developer powder, comprising the step of heating and kneading a developer material containing an inorganic first transition metal compound and a binder resin.