External additive for toner, toner and image forming apparatus

A toner comprising

• a toner particle comprising a binder resin, and
• an external additive,
• wherein the external additive comprises an organosilicon polymer particle, and
• defining A (nm) as the number-average particle diameter of primary particles of the external additive measured using a scanning electron microscope, and
• defining B (nm) as the number-average particle diameter of the external additive measured in accordance with a centrifugal sedimentation method,
• the A and the B satisfy a following Expression (1):
• 1.5≤B/A≤3.0 (1).

An image forming apparatus comprising a cleaning member removing a toner from an image bearing member that supports the toner,

• wherein the toner comprises
• a toner particle comprising a binder resin, and
• an external additive,
• wherein the external additive comprises an organosilicon polymer particle, and
• defining A (nm) as the number-average particle diameter of primary particles of the external additive measured using a scanning electron microscope, and
• defining B (nm) as the number-average particle diameter of the external additive measured in accordance with a centrifugal sedimentation method,
• the A and the B satisfy a following Expression (1):
• 1.5≤B/A≤3.0 (1);
• the cleaning member is a blade formed of an elastic body;
• the blade is in contact with the image bearing member, on account of a pressing force, so that the blade swings about a swing fulcrum;
• and
• the pressing force is from 20 gf/cm to 40 gf/cm, as linear pressure on the image bearing member.