Rubber composition, rubber roller, and image forming device

A rubber composition that is used to form a porous body for an image forming device using electrophotography, the rubber composition comprising:

• a rubber that contains at least one type selected from a group consisting of diene-based rubbers and ethylene propylene-based rubbers, and an ion-conductive rubber;
• a crosslinking component that crosslinks the rubber;
• a foaming component that foams the rubber;
• and
• fine porous particles of at least one type selected from a group consisting of zeolite, activated carbon, and diatomite,
• wherein a total mixing proportion P of the fine porous particles of the three types with respect to a total proportion 100 parts by mass of the rubber satisfies Expression (1):
• P≤Z×35+C×20+D×35 (1)
• [where Z denotes a mass ratio of zeolite, C denotes a mass ratio of activated carbon, and D denotes a mass ratio of diatomite, when a total amount of the three types of fine porous particles is defined as 1].