Roll member, charging unit, process cartridge and image forming apparatus

1. A roll member comprising:

a core, and

an elastic layer arranged on the core, the elastic layer comprising a rubber material having a halogen group and a polyalphaolefin,

wherein the polyalphaolefin is a copolymer of propylene and ethylene or a polymer including butene,

wherein the elastic layer further comprises calcium carbonate having a BET specific surface area of from about 11 m 2 /g to about 70 m 2 /g, in addition to carbon black,

wherein the calcium carbonate is from 20 parts by weight to 100 parts by weight, based on 100 parts by weight of the rubber material,

wherein the elastic layer further comprises at least one selected from the group consisting of quinoxaline and triazine compounds,

wherein the triazine compounds include at least one selected from the group consisting of 2,4,6-trimercapto-1,3,5-triazine, 1-methoxy-3,5-dimercapto triazine, 1-hexyl amino-3,5-dimercapto triazine, 1-diethyl amino-3,5-dimercapto triazine, 1-cyclohexyl amino-3,5-dimercapto triazine, 1-dibutyl amino-3,5-dimercapto triazine, 2-anilino-4,6-dimercapto triazine, and 1-phenyl amino-3,5-dimercapto triazine, and

wherein the calcium carbonate has been surface treated with at least one of a fatty acid, a metal salt of a fatty acid, an alkaline earth metal salt of a fatty acid, or an ester.

2. The roll member according to claim 1 , wherein the content of the polyalphaolefin is from about 1 part by weight to about 40 parts by weight, based on 100 parts by weight of the rubber material.

3. The roll member according to claim 1 , wherein the content of the polyalphaolefin is from about 3 parts by weight to about 30 parts by weight, based on 100 parts by weight of the rubber material.

4. The roll member according to claim 1 , wherein the content of the polyalphaolefin is from about 5 parts by weight to about 20 parts by weight, based on 100 parts by weight of the rubber material.

5. The roll member according to claim 1 , wherein the elastic layer further comprises carbon black having a DBP oil absorption amount of from about 42 ml/100 g to about 175 ml/100 g.

6. The roll member according to claim 1 , wherein the elastic layer further comprises carbon black having a DBP oil absorption amount of from about 60 ml/100 g to about 150 ml/100 g.

7. The roll member according to claim 1 , wherein the elastic layer further comprises carbon black having a DBP oil absorption amount of from about 85 ml/100 g to about 130 ml/100 g.

8. The roll member according to claim 1 , wherein the rubber material is a rubber material having a halogen group.

9. The roll member according to claim 1 , wherein the elastic layer further comprises at least one selected from organic peroxides.

10. A charging unit comprising the roll member according to claim 1 .

11. A process cartridge detachable from an image forming apparatus, comprising:

an image holding member; and

the charging unit according to claim 10 , that charges the image holding member.

12. An image forming apparatus, comprising:

an image holding member;

the charging unit according to claim 10 , that charges the image holding member;

a latent image forming unit that forms an electrostatic latent image on the image holding member charged by the charging unit;

a developing unit that develops the electrostatic latent image formed on the image holding member using a developer comprising a toner; and

a transfer unit that transfers the toner image formed on the image holding member to a recording medium.

13. The roll member according to claim 1 , wherein the calcium carbonate is from 30 parts by weight to 80 parts by weight, based on 100 parts by weight of the rubber material.

14. The roll member according to claim 1 , wherein the calcium carbonate is from 40 parts by weight to 60 parts by weight, based on 100 parts by weight of the rubber material.