Canon Kasei Kabushiki Kaisha

Ayumi Okuda

Hiroshi Abe

Hirobumi Takahashi

Tomoya Kawakami

A contact charging roller includes a support member and a conductive coating member. The conductive coating member is composed of a seamless tube that contains at least (1) a non-polar resin or a styrene-type thermoplastic elastomer excluding a poly(styrene-hydrogentaged butadiene-styrene) block terpolymer and (2) a polar resin or an elastomer having a polar functional group containing at least nitrogen or oxygen, and contains carbon black in an amount of 10% to 60% by mass with respect to the total mass of the non-polar resin or elastomer and the polar resin or elastomer.

Charging roller

Charging roller has at least a support member and a conductive covering member, the charging roller where a value of tan &#x3b4; expressed in a ratio of a storage elastic modulus and a loss elastic modulus by dynamic viscoelasticity in a cross sectional direction of the charging roller at 25&#xb0; C. is 0.2 or more in a range of 1 to 20 kHz and 0.2 or less in a range of 1 to 10 Hz, or a charging roller where the conductive covering member is constructed of two or more layers and a value of tan &#x3b4; in at least one layer other than a surface layer is 0.2 or more at 10 Hz in a range of 10 to 50&#xb0; C. and a value of tan &#x3b4; in a cross sectional direction of the whole charging roller is 0.2 or less at 10 Hz in a range of 10 to 50&#xb0; C.

Charging roller featuring specified ratio of storage elastic modulus and dynamic viscoelasticity values and process cartridge and electrophotographic apparatus featuring the same

In a conductive roller having a conductive substrate, a conductive elastic layer and a conductive cover layer, the conductive cover layer is formed of a seamless tube containing a thermoplastic polymer, the surface of the conductive roller is coated with an inorganic compound the particle surfaces of which have been subjected to hydrophobic treatment, and the roller having been coated therewith has a glossiness of from 7.5% or more to less than 22.0%. This conductive roller can make toner and external additives less adhere to the roller surface, can prevent the faulty images due to the adhesion of photosensitive-member abrasion dust and can well perform charging in the image reproduction from the initial stage to the last.

Growing community of inventors

Moriya, Japan

Ayumi Okuda