Sumitomo Rubber Industries Limited

Yuta Imase

Kei Tajima

There are provided a developing roller having no risks of the image density of formed images rapidly decreasing and the occurrence of an uneven density since a toner transportation amount does not decrease greatly even if image formation is repeated, and a method of producing the same. In a developing roller, a plurality of recesses are disposed on an outer circumferential surface of a roller main body so that a ratio P/Pof a pitch Pin an axial direction on the outer circumferential surface to a pitch Pin a circumferential direction is set to a range exceeding 1.1. The production method includes a process of forming the recesses on the outer circumferential surface by laser processing.

Developing roller and method of producing the same

A developing roller () is provided, which includes a tubular porous inner layer () of a foamed product of a semiconductive rubber composition containing an ethylene propylene rubber and a paraffin oil, and an outer layer () of a seamless tube of a semiconductive thermoplastic polyamide elastomer provided on an outer peripheral surface () of the inner layer (), and has an overall Asker-C hardness of not less than 30 degrees and not greater than 60 degrees. A production method is also provided, which includes the steps of: preparing a tube having a thickness T of 100 to 400 &#x3bc;m and having an inner diameter Dfor an outer layer; preparing a tubular inner layer having an outer diameter D; and press-inserting the inner layer into the tube; wherein an interference represented by a difference D- Dbetween the outer diameter Dof the inner layer and the inner diameter Dof the tube is 100 to 400 &#x3bc;m.

Developing roller, and method of producing the same

The inventive developing roller () includes a roller body () having an outer peripheral surface () which includes a surface roughness component including a multiplicity of asperities and having a void volume Vv of not greater than 0.5 ml/m, and a surface waviness component including a multiplicity of asperities having a longer periodicity than the surface roughness component and having a void volume Vv of not less than 0.05 ml/mand not greater than 3.5 ml/m, the void volumes Vv being each defined as the sum Vvc+Vvv of a core void volume Vvc and a dale void volume Vvv. The inventive production method includes the steps of: polishing the outer peripheral surface (); and finishing the polished outer peripheral surface by at least one method selected from the group consisting of a laser processing method, a wet blasting method and a dry blasting method, so that the outer peripheral surface has a surface geometry satisfying the requirements for the void volumes Vv.

A charging roller is provided which has a simple construction without provision of a coating film and yet is capable of uniformly electrically charging the surface of a photoreceptor body and more advantageously suppressing adhesion and accumulation of fine particles. A charging roller production method is also provided. The charging roller () includes a roller body () having an outer peripheral surface () which includes a surface roughness component including a multiplicity of asperities and having a void volume Vv of less than 0.3 ml/m, and a surface waviness component including a multiplicity of asperities having a lower frequency than the surface roughness component and having a void volume Vv of not less than 0.05 ml/mand not greater than 6 ml/m, the void volumes Vv being each defined as the sum Vvc+Vvv of a core void volume Vvc and a dale void volume Vvv. The production method includes the step of finishing the outer peripheral surface () into a surface geometry satisfying the aforementioned requirements for the void volumes Vv by at least one of laser processing, wet blasting and dry blasting after polishing the outer peripheral surface ().

Charging roller, and method of producing the same

A developing roller is provided, which includes a roller body having a simplified structure without a coating film and yet having a higher wear resistance. The developing roller () includes a roller body () made of a crosslinked product of a rubber composition containing a rubber component including 20 to 50 parts by mass of ECO and/or GECO as an ion conductive rubber and 50 to 80 parts by mass of NBIR based on 100 parts by mass of the overall rubber component, and an oxide film () formed in an outer peripheral surface () of the roller body () by irradiation with ultraviolet radiation or the like.

Developing roller including roller body with simplified structure without a coating film

A semiconductive roller is provided, which includes a tubular main body having a multiplicity of concavities () provided in an outer peripheral surface () thereof in at least one of circumferentially overlapping relation and axially overlapping relation. The concavities are each gently concave toward a center thereof from an outer periphery thereof. A semiconductive roller production method is also provided, which includes the step of forming the concavities by a laser processing method.

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Kobe, Japan

Yuta Imase