Electrophotographic carrier, electrophotographic developer, process cartridge and image forming device
View Patent ↗An electrophotographic carrier includes a magnetic core material and a resin layer that coats the magnetic core material, the resin layer comprising a resistance control agent and a polymer including a repeating unit derived from an alicyclic group-containing methacrylic ester, the resin layer including a monomer as a base material of the repeating unit in the polymer in an amount of from about 0.5% by weight to about 3.0% by weight relative to the total amount of the resin layer.
1. An electrophotographic carrier comprising:
a magnetic core material; and
a resin layer that coats the magnetic core material,
the resin layer comprising a resistance control agent and a polymer including a repeating unit derived from an alicyclic group-containing methacrylic ester, and the resin layer comprising a monomer as a base material of the repeating unit in the polymer in an amount of from about 0.5% by weight to about 3.0% by weight relative to the total amount of the resin layer.
2. The electrophotographic carrier according to claim 1 , wherein the polymer further comprises a repeating unit derived from a chain group-containing methacrylic ester.
3. The electrophotographic carrier according to claim 2 , wherein a ratio by weight of the repeating unit derived from a chain group-containing methacrylic ester to the repeating unit derived from an alicyclic group-containing methacrylic ester (the repeating unit derived from a chain group-containing methacrylic ester/the repeating unit derived from an alicyclic group-containing methacrylic ester) is from about 1/99 to about 20/80.
4. The electrophotographic carrier according to claim 1 , wherein a weight average molecular weight of the polymer is from about 4.0×10 4 to about 3.0×10 5 .
5. The electrophotographic carrier according to claim 1 , wherein a volume average particle diameter of the carrier is from about 30 μm to about 90 μm.
6. The electrophotographic carrier according to claim 1 , wherein a thickness of the resin layer is from about 0.3 μm to about 10 μm.
7. The electrophotographic carrier according to claim 1 , wherein the alicyclic group-containing methacrylic ester is cyclohexyl methacrylate.
8. The electrophotographic carrier according to claim 1 , wherein the resistance control agent comprises carbon black.
9. An electrophotographic developer comprising:
the electrophotographic carrier according to claim 1 ; and
a toner.
10. The electrophotographic developer according to claim 9 , wherein the toner comprises a polyester resin as a binder resin.
11. The electrophotographic developer according to claim 10 , wherein the polyester resin further comprises a crystalline polyester resin.
12. The electrophotographic developer according to claim 9 , wherein the toner comprises an amide wax as a releasing agent.
13. The electrophotographic developer according to claim 9 , wherein the toner comprises silicon dioxide and titanium oxide as external additives.
14. A process cartridge including at least a developer holding member, wherein the process cartridge accommodates the electrophotographic developer according to claim 9 .
15. An image forming apparatus comprising:
a latent image holding member;
a developing unit that develops an electrostatic latent image formed on the surface of the latent image holding member as a toner image using the electrophotographic developer according to claim 9 ;
a transfer unit that transfers the toner image formed on the surface of the latent image holding member to an image receiving body; and
a fixing unit that fixes the toner image that has been transferred to the image receiving body.