JPH0545030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in carriers used together with toner as electrophotographic developers.

2. Description of the Related Art Conventionally, in the development process of electrophotography, the carrier of a two-component developer consisting of toner and carrier is coated with a coating material such as a resin.

Among these, carriers coated with fluororesin (for example, polytetrafluoroethylene) have low surface energy and a low coefficient of friction, making it difficult for toner to fuse to the carrier surface, and the developer itself has good fluidity. There are advantages such as

However, on the other hand, the coating layer has the drawback that it is easily peeled off or damaged by mechanical shocks such as toner collisions, shearing force, etc., and the coating layer decreases over time and eventually disappears. be.

Problems to be Solved by the Invention An object of the present invention is to solve the above-mentioned conventional drawbacks, and to provide a carrier having a coating layer with excellent wear resistance and in which toner is difficult to fuse. .

Means and Effect for Solving the Problems The present invention provides a core material whose surface has been pretreated with zinc phosphate, a fluororesin coating the surface of the core material, and a polyether sulfone and/or alkyl group. , and a substituted polyether sulfone having a halogen group, an alkoxy group, an acetoxy group, or an amino group as a substituent.

As the core material coated with the coating material of the present invention, conventionally well-known metal particles, glass, etc. are used, and the size of the core material is approximately 0.1 to
Particles of 1000μ are preferred.

The thickness of the coating layer is preferably about 3 to 30 microns, more preferably 5 to 15 microns.

Such a resin mixture is in the form of a heat-resistant coating for mold release under the trade name Okitsumo Peslon One Coat.
PL-1, PL-5, PL-10, PL-20, PL-282,
It is commercially available as PL-1000 (manufactured by Mie Yushi Kako Co., Ltd.), and these can be used in the present invention.

The resin-coated carrier, which is made by coating a core material whose surface has been pretreated with zinc phosphate with the above resin mixture, is resistant to mechanical impact and does not peel off or peel off even during long-term use, as described in the examples below. It does not disappear and is extremely excellent in various properties required as a carrier, such as charging characteristics, fluidity, and moisture resistance. Furthermore, by treating the core material with zinc phosphate in advance, oxidation of the core material during the coating process and during heating after the coating process can be suppressed.

Examples will be explained below.

Example Okitsumo Peslon One Coat PL-1000 (manufactured by Mie Yushi Kako Co., Ltd., a coating agent in which a mixture of polyether sulfon and fluororesin manufactured by ICI is dispersed) was applied using air spray to determine the average particle size. 90 to 150 c.c. per 1 kg to a 300μ iron ball
The coating was applied in a circulating fluidized bed at 95°C.

Then, it was baked in a hot air dryer at 370℃ for 15 minutes.
It was a carrier. The iron ball was pretreated with a zinc phosphate solution.

20g of this carrier into an 8mm diameter stainless steel ball
After stirring for 8 hours at a rotation speed of 250 r.pm in a ball mill containing 20 pieces, it was placed in a 1% sodium dodecyl sulfonate aqueous solution, and no fragments of the carrier coating were found, forming a highly durable coating. It turned out that it was done.

In addition to the above embodiments, various carrier core materials and toners can be used to obtain a developer having the same effects as those described above, and the present invention is not limited to the above embodiments.

Comparative example A film of polytetrafluoroethylene enamel 851-24 (manufactured by Dupont) was applied to an iron ball with an average particle size of 300μ.
After coating at a thickness of 10 μm, it was sufficiently dried to form a carrier.

When this carrier was subjected to the same wear resistance test and fusion test as in Example 1, fragments of the carrier coating were observed in a 1% sodium dodecyl sulfonate aqueous solution, indicating that the coating layer was considerably worn. It turned out that.

Effects of the Invention In the carrier for electrophotographic developer of the present invention, by coating the core material with the mixed resin specified in the present invention, toner is difficult to fuse to the carrier surface without impairing the fluidity of the developer itself. Moreover, it has become possible to provide a carrier whose coating layer is not easily peeled off or damaged by mechanical impact such as toner collision or shearing force.

Claims (1)

[Claims] 1 A core material whose surface has been pretreated with zinc phosphate, a fluororesin coating the surface of the core material, and a polyether sulfon and/or alkyl group, halogen group, alkoxy group, acetoxy group, or amino group. 1. A resin-coated carrier for an electrophotographic developer, comprising a mixed resin comprising a substituted polyether sulfone having a group as a substituent.