Charging member, process for its production, process cartridge and electrophotographic apparatus

A charging member which comprises a substrate, an elastic layer and a surface layer;

• wherein
• the surface layer contains a polymer having an Si—O—W linkage;
• and
• the polymer has a constitutional unit represented by the following formula (1) and a constitutional unit represented by the following formula (2):
• where, in the formula (1), R1 and R2 each independently represent any of structures represented by the following formulas (3) to (6):
• where, in the formulas (3) to (6), R3 to R7, R10 to R14, R19, R20, R25 and R26 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atom(s), a hydroxyl group, a carboxyl group or an amino group;
• R8, R9, R15 to R18, R23, R24 and R29 to R22 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atom(s);
• R21, R22, R27 and R28 each independently represent a hydrogen atom, an alkoxyl group or alkyl group having 1 to 4 carbon atom(s);
• n, m, l, q, s and t each independently represent an integer of 1 to 8, p and r each independently represent an integer of 4 to 12, and x and y each independently represent 0 or 1;
• and an asterisk * and a double asterisk ** each represent the position of bonding with the silicon atom and oxygen atom, respectively, in the formula (1).