JPS5840737B2 - Method for producing electrophotographic developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing an electrophotographic developer with improved fluidity and cohesion.

Toners used in electrophotography are divided into so-called two-component toners, which are mixed with a carrier, and one-component toners, which are developed using only toner, depending on the developing method.

In the former case, the carrier toner system is normally replenished with toner as the toner is consumed, while in the latter case, of course, only the toner is replenished.

Conventionally, various methods have been considered for toner replenishment, but in any method, in order to replenish toner smoothly, it is desirable that the toner has good fluidity, and this is especially important for component-based toner. This has become a major issue.

Furthermore, toner tends to cause blocking and caking during storage, which impairs the quality of images or, in severe cases, renders them unusable.

Such a phenomenon is particularly likely to occur with toner produced for the purpose of lowering the fixing temperature.

For example, it has been well known that non-adhesive substances, especially inorganic fine powder, are added to toner to improve its fluidity and cohesiveness, but the surface of the toner is coated with infusible fine powder. Therefore, the fixing performance is reduced.

It is also known that the fluidity and cohesiveness can be improved by adding fatty acid metal salts, etc., but the effect is small unless added in large amounts, and if added in large amounts, other physical properties of the toner such as charging properties are impaired. This is often the case.

In addition, fluorocarbon polymers such as polyvinyl fluoride have low surface energy and are known to have excellent lubricity and non-adhesive properties, but their melt viscosity is high and they are difficult to mix with other materials, so they are used in toners. It is difficult to use it by adding it to.

Furthermore, as a physical method, a method has been proposed in which the toner is sphericalized to improve its fluidity.

In particular, there is a method to obtain spherical toner by spray drying resin latex, but since the surfactant used in resin latex is hygroscopic, it will flow unless the resulting powder is washed with water to remove the surfactant. It also had the disadvantage of poor moisture resistance.

The present invention aims to improve such drawbacks and to produce a spherical toner from resin latex without a water washing process, and to produce a toner with excellent fluidity and moisture resistance, and a good image effect.

That is, a suspension is created by dispersing pigments, magnetic materials, etc. in a resin latex that has been emulsion polymerized using a perfluoroalkyl compound surfactant, and this suspension is spray-dried to form a fine spherical shape. A method for producing an electrophotographic developer, characterized by:

Examples of perfluoroalkyl compound surfactants used here include compounds such as Haggi.

(1)X(CF2)ncOOH2X(CF2)nCH20PO(OH)23X(C
F2) nCH2SO3H 4H (CF 2 ) nPO(OH)2 5 X (CF'2) ncH2NR26X (CF2
)n(OCH2CH2)mOH (where X=H or F
, n-=6-12, R-alkyl having 1-4 carbon atoms, m-
=6~12)(7) NH4 of (1) or 4),
Alkali metal salts (8) (5) HCI, H2SO4, H
Monomers that undergo salt polymerization of 2PO4 include ethylene, acrylonitrile, vinyl acetate, vinyl chloride, styrene methacrylate, acrylate, and mixtures thereof.

In the present invention, surfactants used in conventional methods can also be used together, but in that case, it is necessary to use 50% or more of the perfluoroalkyl compound.

Since the perfluoroalkyl compound surfactant exhibits water and oil repellency after drying, a toner with improved fluidity and cohesiveness can be obtained without the need for a water washing step unlike in conventional methods.

Next, embodiments of the present invention will be described.

Example 1 Add 0.00 ammonium persulfate to 200 liters of ion-exchanged water.
3. Dissolve 1.01 of potassium perfluoroalkyl sulfonate (trade name Florard EC128, manufactured by 3M Company),
Methyl methacrylate 40 in this? , butyl acrylate 1
01 was emulsified and heated to 85° C. with stirring.

If it starts to reflux, add 40 more methyl methacrylate.
, butyl acrylate 101 was added dropwise and reacted at 85° C. for 3 hours to obtain a resin latex.

To this resin latex, 100 r of triiron tetroxide fine powder and 3C1 carbon blank were added, and after kneading with a ball mill, ion-exchanged water was added to this so that the solid content concentration was 5%.
A spherical toner was obtained by spray drying.

When the toner produced in this way was developed using Nuricopy NT 630 (manufactured by Ricoh Co., Ltd.), an extremely clear image was obtained.

In addition, although continuous copying was performed, no problems related to fluidity or cohesiveness occurred in toner replenishment.

Example 2 Ammonium peroxide 0.3P in 200ml ion-exchanged water
, 0.7 g of potassium perfluoroalkyl sulfonate (trade name Florard FC95, manufactured by 3M) and 0.21 g of sodium lauryl sulfate were added to this, 41' styrene and 20 P of butyl methacrylate were added, and the mixture was stirred for 20 minutes. While maintaining the temperature at 85°C, 4C1 styrene and 20 g of butyl methacrylate were added dropwise, and the mixture was heated at 85°C for 3 hours to obtain a resin latex.

Add to this 100 g of triiron tetroxide fine powder, and 1 carbon black.
M' was added and mixed using a ball mill, ion-exchanged water was added to adjust the solid content concentration to 5%, and the mixture was spray-dried to obtain a magnetic toner.

Using a photosensitive plate coated with acrylic resin and ZnO in a ratio of 7:3 on an aluminum plate, toner is attached to a cylindrical sleeve containing a magnetic pole and rotated to develop an electrostatic latent image.
This was transferred onto plain paper by charge transfer.

This operation was performed in an atmosphere of 30° C. and 70% RH, and a clear image was obtained.

As described above, the present invention provides a toner that does not cause any problems with the fluidity or cohesiveness of the toner, does not cause deterioration in the quality of copied images even when used indoors with high humidity, and does not require a washing process. Since there is no such thing, manufacturing is easy.

Furthermore, since spray drying is carried out in water, there is no risk of pollution such as the scattering of solvents.

Claims (1)

[Claims] 1 A suspension is created by dispersing a pigment magnetic material, etc. in a resin latex that has been emulsion polymerized using a perfluoroalkyl compound surfactant, and this suspension is spray-dried to form a fine spherical shape. A method for producing an electrophotographic developer.