CHARGING MEMBER, METHOD FOR MANUFACTURING CHARGING MEMBER, ELECTROPHOTOGRAPHIC DEVICE, AND PROCESS CARTRIDGE

• Main Authors: FURUKAWA TAKUMI, WATANABE HIROAKI, TERADA KENYA, TOMOMIZU YUYA, NAKAZAWA TOSHIMITSU
• Format: Patent
• Language: English; Japanese
• Published: 31.10.2019
• Subjects: CHEMISTRY; CINEMATOGRAPHY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; MAGNETOGRAPHY; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHOTOGRAPHY; PHYSICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS

To provide a charging member that achieves high stability of electric potential even when a difference in peripheral velocity between a body to be charged and the charging member is large.SOLUTION: The charging member comprises a conductive support and a single-layer elastic layer as a surface layer. The elastic layer has domains containing carbon black and rubber, and a matrix having a higher electrical resistance than that of the domains and containing rubber. The surface of the charging member is formed of the surface of the matrix and surfaces of the domains and has a plurality of concave parts. The domains are present at the bottom parts of the concave parts and exposed to the surface of the charging member only at the bottom parts of the concave parts. The volume resistivity of the elastic layer is 1×10or more and 1×10Ω cm or less. When a current value when a DC voltage of 80 V is applied between the conductive support and the surface of the matrix is A1, and a current value when a DC voltage of 80 V is applied between the conductive support and the surfaces of the domains is A2, A2 is 20 times or more of A1.SELECTED DRAWING: Figure 1 【課題】被帯電体と帯電部材との周速差が大きい場合にも電位の安定性が高い帯電部材を提供する。【解決手段】該帯電部材は、導電性支持体と、表面層としての単層の弾性層とを有し、該弾性層は、カーボンブラックおよびゴムを含むドメインと、ドメインよりも高い電気抵抗を有する、ゴムを含むマトリックスと、を含み、帯電部材の表面は、マトリックスの表面と、ドメインの表面とで構成され、複数個の凹部を有し、ドメインは凹部の底部に存在し、かつ、凹部の底部においてのみ帯電部材の表面に露出しており、弾性層の体積抵抗率は、１×１０５以上１×１０８Ωｃｍ以下であり、該導電性支持体と、該マトリックスの表面と、の間に８０Ｖの直流電圧を印加した際の電流値をＡ１とし、該導電性支持体と、該ドメインの表面と、の間に８０Ｖの直流電圧を印加した際の電流値をＡ２としたとき、Ａ２が、Ａ１の２０倍以上である。【選択図】図１