JPS5850544A - Manufacture of electrophotographic toner - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic toner fine in size and improved in consumption of energy in manufacture, by emulsion-polymerizing a polymerizable monomer in an aq. soln. of surfactant and stabilizer in the presence of magnetic material dispersed in it. CONSTITUTION:A polymerizable monomer is emulsion-polymerized in a aq. soln. of sufactant and atabilizer in the presence of a magnetic material dispersed in it. As the surfactant, especially an anionic surfactant is preferable, and the suitable amount of it to be used is 0.1-10pts.wt. per 100pts.wt. water. Use of a too small amount of it produces coarse particles and use of a too large amount produces too fine particles not suitable for toner. A preferable amount of magnetic material to be added is 20-200pts.wt. per 100pts.wt. of the monomer used. Use of an amount less than 20pts.wt. causes insufficient magnetic attachment force, and use of an amount exceeding 200pts.wt. tends to deteriorate fixability to paper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for making electrophotographic toners, particularly -component toners.

The toner used in electrophotography is a two-component developer toner that is released by frictional charging with a carrier according to the current method;
There is a one-component toner that performs the 1' phenomenon using only toner.

The present invention is directed to an improved method of manufacturing -component toners.

Conventionally, the production of -component toner 1 involves a step of melting and kneading the materials and then mechanically pulverizing them to predetermined particles If (usually 5 to 50 μm on average) by jet pulverization or the like. Since the efficiency of the grinding process suffers, a large amount of energy is consumed to obtain the toner per unit amount. Furthermore, if necessary, after the pulverization process, there is a process of compressing the toner into a perfect spherical shape in order to improve the transportability of the toner inside the developing machine, and a process of fusing carbon black on the surface of the toner to improve the feel of the toner. , manufacturing cost increases.

Methods for producing one-component toner include an emulsion polymerization solution of a binder resin in addition to the Jokiryu@Onbei-pulverization method.

Alternatively, there is a method of obtaining a toner by dispersing and suspending a magnetic material or a colorant in a resin solvent solution, followed by mist drying (Japanese Patent Publication No. 43-10799, Japanese Patent Publication No. 35-79
Publication No. 23, etc.).

However, these methods only replace the horizontal pulverization with spray drying, and the number of steps is not the same as that of the jet pulverization method, but there is a drawback that a large amount of thermal energy is consumed during the spray drying.

The present invention is a book related to a toner manufacturing method that solves one or more problems in toner manufacturing, namely, that a large amount of energy is required to obtain a unit amount of toner.

That is, the present invention relates to a method for producing a fine electrophotographic toner, which is characterized by emulsion polymerizing a polymerizable monomer while dispersing a magnetic material in an aqueous solution in which a surfactant and a stabilizer are dissolved. In the invention, it is necessary to use a surfactant and a stabilizer in combination; if only one of them is used, a fine toner cannot be obtained.

Surfactants include anionic, nonionic, and cationic surfactants, but anionic surfactants especially
For example, dodecylben-'d7 sodium sulfonate,
Sodium lauryl sulfate, sodium dioctyl sulfosuccinate, sodium alkyldiphenyl disulfonate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether sulfate triethanolamine.

Polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl ether sulfate triethanolamine, alkyl sulfate triethanolamine, alkylphenyl ether sulfate salt, etc., per 100 parts by weight of water.

It is used in an amount of 0.1 to 10 parts by weight, more preferably 1 to 2 parts by weight. If the amount of surfactant is too small, the particles to be scratched by the synthesis will be coarse; if it is too large, the particles will become too fine, making them unsuitable as a toner.

Stabilizers include polyvinyl alcohol, partially saponified polyvinyl alcohol, 100% cellulose, methylcellulose, gelatin, polyvinylpyrrolidone, etc.
It is used in an amount of 0.1 to 1011 parts, more preferably 1 to 3 parts by weight, based on the amount of water used. If the amount of the stabilizer is too small, the toner will become sticky, and if it is too large, the resulting toner will have absorption properties, which is not preferable.

The polymerizable seven-layer polymer is one in which a resin component obtained by polymerization serves as a binder for toner.

Ethylene, acrylonitrile, vinyl acetate, vinyl chloride, styrenic monomers (e.g., styrene, vinyltoluene), vinylvinylene, methacrylic acid esters (e.g., methyl methacrylate).

ethyl methacrylate, butyl methacrylate), a) These can be used alone or in combination. The type and amount of the polymerizable monomer are mainly determined by the intended thermal properties of the toner, such as the fixing temperature. In emulsion polymerization using only the above monomers.

If the molecular weight becomes too large and the resulting Tonerka I has a high softening point, which is disadvantageous, use mercaptan.

A linear transfer agent such as carbon tetrachloride or phenol may be used in combination. The amount of the continuous transfer agent used is 0.2 to 4 parts by volume per 100 parts by volume of polymerizable 7mer.

In general, in order to obtain a heat fixing toner, it is preferable that the softening point of the resin is 35 to 160°C. As the amalgamating seven-mer, preferred are styrenic medicinal agents, methacrylic esters, acrylic esters, and the like.

Magnetic materials include alloys or compounds containing ferromagnetic elements such as ferrite and magnetite, as well as iron, cobalt, and nickel.

Or alloys such as manganese-steel-aluminum, manganese-steel-tin, or chromium dioxide, yttrium, etc., which exhibit ferromagnetism through appropriate heat treatment? Iron, garnet, etc. The amount of magnetic material added is 10%
It is preferable to set it as 20-200@@@ parts with respect to 0 parts by weight. If the amount is less than 20 parts by weight, the adhesion force due to magnetic force to the magnet roll will be insufficient, making it impossible to convey the material at the same time. Moreover, if the amount exceeds 2.00 parts, the resin content will be too small, and the fixing property to the adhesive will tend to deteriorate. The magnetic material preferably has a particle size of 0.3 to 0.5 μm, and has a grain density of α5 to 0.7 f/cm. In addition, optional colorants may be used as necessary. (1) Pigments can be added to the polymerization system where dyes are used.

Pigments include carbon black, contact black,
Furnace black, thermal black.

Lamp black, Phthalocyanine Blue, Phthalocyanine Clean, Hanzai Yellow G, Rhodamine 6G Lake, Pigment Red 48. Watching red Ba etc. are added to 100 parts by weight of polymerizable monomer.
It is preferable to have a caloric content of ~20 parts by weight, more preferably 0
Add ~10 parts by weight. As a dye, oil black B
S (manufactured by Orient Chemical Industry), Luxol Fast Bull = AR (E, 1. Manufactured by Dupont), =! a thin 5SB
(C, I, 50415), Safzan T (C, I, 582
50), Azo Oil Black 7 (allied chemical connivoration), etc.
It is preferable to add 0 to 20 parts by weight, more preferably 0 to 5 parts by weight per 00 parts by weight. Furthermore, other known additives added as toner components include calcium carbonate, madaosium carbonate, magnesium hydroxide,
Examples include calcium sulfate, magnesium oxide, calcium silicate, and silica, but magnesium carbonate and calcium carbonate are particularly preferred. The blending amount of these additives is 0 to 100 parts by weight of polymerizable 7mer.
A suitable amount is 203i parts, and the addition of this makes it possible to further suppress the bridging phenomenon.

In the present invention, a surfactant and a stabilizer such as polyvinyl alcohol are dissolved in water, a magnetic material 1 polymerizable monomer is suspended therein, and a water-soluble polymerization initiator is 1, for example, potassium persulfate.

Contains ammonium persulfate, sodium metabisulfite, etc. 0.1~'LO per 100 parts by weight of monopolymerizable heptamer
Use in the weight section. As the polymerization progresses, the two particles enlarge and coalesce to form particles of 5 to 50 μm. The particle size of the resulting particles can be adjusted within a range of 5 to 50 μm by adjusting the amounts of surfactant and stabilizer. Although the stirring speed also affects the particle size, the stirring speed generally used in emulsion polymerization may be used. At this time, a magnetic material and a pigment according to the required VC are dispersed in the resin, but the polymerization rate suddenly decreases midway due to the polymerization inhibiting effect of the magnetic material and the like. To solve this problem, a water-soluble polymerization initiator is gradually added during monopolymerization. If you do this.

Polymerization of the monomers continues to occur on the particle surface, and 9 polymerization can be completed. Furthermore, in the case of component toner, the current gj! In order to improve the properties, carbon black is sometimes fused to one surface, but in the present invention, it can be easily fused if a carbon blank is added at the end of 1 synthesis.

In the present invention, the binder resin magnetic material, the pigment melting and mixing process, the jet powder, the crushing process and the spheroidizing process are unnecessary.
The reason is that a toner with good fluidity can be obtained by simply passing the powder and granular material from the mixed solution and drying it.

Next, examples of the present invention will be shown.

Example 1 Dissolve 4FI of sodium dodecylbenzene sulfonate in 400ml of water to dissolve 6h of polyvinyl alcohol (trade name: Denka Poval W-72.4, manufactured by Denki Kagaku Kogyo ■) to obtain magnetic powder.

(Totacolor, KN-320. Manufactured by EB Kogyo ■) 15.
(100% of styrene), 50% of butyl acrylate, 3i of i-dodecylmercaptan, and 0.51% of potassium persulfate were added and emulsified, and the temperature was raised to 70°C. After 2 hours, add 50ml of 2% potassium persulfate aqueous solution to approx.
Drop it over a period of time, then raise the temperature to 90°C.

Allow to react for 4 hours. Cool until it reaches its peak, filter with Pg,
A toner was obtained by drying under reduced pressure. . The obtained toner has a particle size of 5 to 50 μm and can be used with an electrophotographic copying machine, resulting in extremely clear images! Ta. Although copies were made continuously, no deterioration in image quality or deterioration in image density was observed, and no problems due to fluidity or cohesiveness occurred during toner replenishment.

Example 2 Polyvinyl 7-Ncol (trade name Denka Popal W-24, manufactured by Denki Kagaku Kogyo ■) 8F was added to 40011 liters of water.

Dissolve 6 tons of sodium dodecylbenzenesulfonate.

While dispersing magnetic powder (Mapico Black Bl [, -500, manufactured by Titan Kogyo ■] 150), styrene 120
), butyl acrylate SOP, 25t of t-dodecylmercaptan, and potassium persulfate α5 were added and emulsified at 70°C.
The temperature rises to After 2 hours, potassium persulfate 2 aqueous solution 50-
was added dropwise over a period of about 2 hours, and then the temperature was raised to 90°C and the reaction was carried out for a period of time.

Carbon black (MA8. manufactured by Mitsubishi Kasei) 5P was dispersed in a 2-polj vinyl alcohol aqueous solution 30- and added dropwise.
Allow to react for an additional hour. After cooling to 1 temperature, e
The mixture was filtered and dried under reduced pressure to obtain a toner. The obtained toner had a particle size of 3 to 405 m, and was developed using an electronic copying machine, resulting in an extremely clear single image, with particularly excellent reproduction between parts. When copying was carried out nine times in a row, no deterioration in image quality or deterioration in image density was observed, and there were no problems with toner replenishment due to fluidity or consistency.

Actual example 3: 400 d of water and polyvinyl alcohol (Denka Poval W)
-24. Dissolve 6P (manufactured by Denki Kagaku Kogyo ■), sodium dodecylbenzenesulfonate 6), disperse magnetic powder (Mavico Black BL-500. manufactured by Titanium Industry ■150), and add styrene 120P, butyl acrylate 3).
0), l-dodecyl mercaptan 3? , magnesium carbonate 1P, 2f of t-dodecylmerkabutane, and 0.5t of potassium persulfate are added and emulsified, and the temperature is raised to 70°C. After 2 hours, 50 ml of potassium sulfate 2-aqueous solution was added dropwise over about 2 hours, and then the temperature was raised to 90°C and reacted for 4 hours. I
After cooling to the temperature of A, the toner was filtered with P paper and dried under reduced pressure to obtain a toner. The obtained toner has a particle size of 5 to 50 fi
, I used an electrophotographic copying machine to print a current monk at m, and fc
A very clear 11Ⅲ water was obtained.

This toner was left in an atmosphere at 50° C. for 24 hours, but no toner blocking phenomenon occurred.

Comparative Example 1 40011 water and 44% sodium dodecylbenzenesulfonate?
and disperse magnetic powder (Todacolor KN-320゜manufactured by Toda Kogyo ■ 150).

Styrene 101', butyl acrylate, 3P dodecyl mercaptan, and 0.51 potassium persulfate were added to emulsify the mixture, and the temperature was raised to 70°C. Due to the t&MA phenomenon for 2 hours, the toner became sticky and no toner was obtained.

Comparative Example 2 Water + 00d and polyvinyl alcohol (trade name Denka Popal W-24. Manufactured by Denki Kagaku Kogyo ■) 6? Melt it and add 150P of magnetic powder (Todacolor KN-320. Manufactured by Toda Kogyo ■)
In addition to dispersing the styrene 100? , butyl acrylate sot, t-dodecylmercaptan 3F, and potassium persulfate 0.51 were added and suspended, and the temperature was raised to 70°C.

Claims (1)

[Claims] 1. A method for producing a fine electrophotographic toner, which comprises emulsion polymerizing a polymerizable monomer while dispersing a magnetic material in an aqueous solution containing a surfactant and a stabilizer. A method for producing a fine electrophotographic toner according to claim 1, wherein 1 to 10 parts by weight of a surfactant and a stabilizer are dissolved in 100 parts by weight of water. λ 2 parts by weight of magnetic material per 100 parts by weight of polymerizable heptamer
A method for producing a fine electrophotographic toner according to claim 1 or 2, wherein 0 to 200 parts by weight are dispersed.