Carrier and a production method thereof for developing an electrostatic image
AssigneeKonica Corporation
InventorsShigenori Kouno, Ken Ohmura, Yoshiaki Koizumi, Kenji Tsujita
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Abstract
There is disclosed an electrostatic image-developing carrier having a resin coat layer with an excellent mechanical strength. The carrier is prepared by repeatedly applying a mechanical impact force to the mixture of the core particle and the coating resin particle in a dry condition, wherein a molecular weight distribution chromatogram according to a gel permeation chromatography of a tetrahydro-furansoluble component in the resin coat layer has at least one peak or shoulder in a molecular weight range 1,000 to 20,000.
Claims14
An electrostatic image-developing carrier comprising a ferrite core particle and a resin coat layer provided thereon by applying repeatedly a mechanical impact force to the mixture of the ferrite core particle and a single type of coating resin particle in a dry condition,
- wherein the ferrite core particle and the coating resin particle are mixed at a temperature less than the glass transition point of the resin particles for time less than or equal to 20 minutes and
- wherein the temperature of the resin layer-forming process is less than or equal to about 97.degree. C. and the stirring speed of the resin layer-forming process is 5.8 to 12.6 m/sec, and
- wherein a molecular weight distribution chromatogram according to a gel permeation chromatography of a tetrahydrofuran-soluble component in the resin coat layer has at least one peak or shoulder in a molecular weight range of 1,000 to 20,000 and said peak or shoulder accounts for 5 to 65% of the area of the chromatogram.
A method of preparing an electrostatic image-developing carrier comprising a core particle and provided thereon a resin coat layer, comprising:
- a mixing process in which the ferrite core particle and a single type of coating resin particle are mixed at a temperature less than the glass transition point of the resin particles for a time less than or equal to 20 minutes, and
- a resin layer-forming process in which a mechanical impact force is repeatedly applied to the mixture of the core particle and a single type of coating resin particle in a dry condition to form the resin coat layer on the core particle, at a temperature of less than or equal to about 97.degree. C. and a stirring speed of 5.8 to 12.6 m/sec,
- wherein a molecular weight distribution chromatogram according to gel permeation chromatography of a tetrahydrofuran-soluble component in the resin coat layer has at least one peak or shoulder in a molecular weight range of 1,000 to 20,000 and said peak or shoulder accounts for 5 to 65% of the area of the chromatogram.
Dependencies are inferred from the claim text.