Developing device having magnetic sealing member and image forming apparatus including the same

An image forming apparatus comprising:

• an image bearing member;
• a charging device which charges the image bearing member uniformly;
• an exposure unit which exposes the image bearing member based on image information;
• a fixing unit which fixes a toner on a recording medium;
• and
• a developing device comprising:
• a housing comprising magnetic developer;
• a developer bearing member which is rotatably supported by the housing and is configured to hold the developer with a magnet member disposed in the developer bearing member;
• a developer regulating member which extends along a longitudinal direction of the developer bearing member, having a recessed-shaped cut portion at each end portion of the developer regulating member in a surface facing the developer bearing member, each recess-shaped cut portion comprising a first side-wall surface portion and a second side-wall surface portion that each extends upwardly toward the developer bearing member from a respective end portion of a lower surface portion of the recess-shaped cut portion such that the recess-shaped cut portion includes an opening partially bounded by the lower surface portion and the first and second side-wall surface portions;
• and
• a magnetic sealing member which extends along an outer peripheral surface of the developer bearing member at each end portion of the developer bearing member in the longitudinal direction thereof, and extends to come in contact with the recess-shaped cut portion from an upstream side in a rotational direction of the developer bearing member, such that a surface of the magnetic sealing member faces the developer bearing member and an opposite surface of the magnetic sealing member faces the lower surface portion of the recess-shaped cut portion, and wherein a width of the magnetic sealing member is smaller than a width of the cut portion.

A method of inhibiting leakage of the developer during a printing process, comprising:

• providing one or more magnetic sealing members at an end of a developing device having one or more recess-shaped cut portions each comprising a first side-wall surface portion and a second side-wall surface portion that each extends upwardly from a respective end portion of a lower surface portion of the recess-shaped cut portion such that the recess-shaped cut portion includes an opening partially bounded by the lower surface portion and the first and second side-wall surface portions, the magnetic sealing members extending along an outer peripheral surface of a developer bearing member positioned proximate an end portion of the developer bearing member, a portion of the magnetic sealing member being positioned substantially within the opening and between the first and second side-wall surface portions of the recessed-shaped cut portion of the developer regulating member, and a surface of the magnetic sealing member facing the developer bearing member and an opposite surface of the magnetic sealing member facing the lower surface portion of the cut portion;
• providing a magnet member in a developer bearing member proximate the magnetic sealing member;
• providing developer to a surface of the developer bearing member;
• and
• allowing a magnetic field to form between the magnetic sealing member and the magnet member such that a magnetic field inhibits movement of the developer beyond a plane corresponding to the edge of the magnetic sealing member.