Developing Device And Electrophotographic Image Forming Apparatus Using The Same

A developing device to perform development by supplying toner of a developer in which the toner and a carrier are mixed to an electrostatic latent image formed on an image bearing member, the developing device comprising:

• a development member to attach a developer to an outer circumferential surface of the development member and supply the toner to the image bearing member;
• a first regulating portion to form a first doctor gap between the outer circumferential surface of the development member and the first regulating portion;
• and
• a second regulating portion disposed on an upstream side of the first regulating portion in a rotational direction of the development member to form different pressures of the developer at both end portions and a central portion in a longitudinal direction of the development member.

An electrophotographic image forming apparatus using a developer in which toner and a carrier are mixed, the electrophotographic image forming apparatus comprising:

• an image bearing member on which an electrostatic latent image is formed;
• and
• a developing device to perform development by supplying the toner to the electrostatic latent image formed on the image bearing member, the developing device comprising:
• a development member to attach the developer to an outer circumferential surface of the development member and supply the toner to the image bearing member,
• a first regulation member that comprises a first regulating portion to form a first doctor gap between the outer circumferential surface of the development member and the first regulating portion, and
• a second regulation member disposed on an upstream side of the first regulation member in a rotational direction of the development member and comprising a second regulating portion to form second doctor gaps between the outer circumferential surface of the development member and the second regulating portion,
• wherein the second doctor gaps at a central portion and both end portions in a longitudinal direction of the development member are different from each other.

A developing device to supply toner in a developer to a photosensitive drum to form an image on a printing medium, the developing device comprising:

• a developing roller having an outer circumferential surface to attach the developer thereto and to supply the toner to the photosensitive drum;
• a first regulation member to form a first doctor gap with the outer circumferential surface of the developing roller;
• and
• a second regulation member disposed upstream of the first regulation member to form second doctor gaps with the outer circumferential surface of the developing roller that are larger than the first doctor gap, at least one of the second doctor gaps being different in size than the remaining second doctor gaps.