Toner feeder, toner, and electrophotographic image forming apparatus using the toner feeder and toner

An electrophotographic image forming apparatus comprising:

• a photoreceptor;
• a charger configured to charge the photoreceptor;
• an irradiator configured to irradiate the photoreceptor with light to form an electrostatic latent image on the photoreceptor;
• an image developer configured to develop the electrostatic latent image with a developer comprising a toner comprising toner powders having an aggregation not greater than 20% and circularity not less than 0.93;
• and
• a toner feeder comprising a container configured to contain the toner prior to use in the developer, a pipe configured to transport the toner, and a pump configured to feed the toner from the container through the pipe,
• wherein the pump feeds the toner to the image developer through the pipe and comprises a screw pump having a female screw stator having a double-pitch spiral groove on an inner surface thereof, and a male rotor rotatably inserted into the female screw stator.