Developing apparatus having a magnetic seal

A developing apparatus comprising:

• a container for accommodating a developer containing magnetic particles;
• a rotatable developer carrying member, disposed at least partly in said container, for facing an image bearing member at a developing position and for carrying the developer thereon to the developing position;
• a magnet disposed in said developer carrying member;
• a magnetic member disposed closely to and along said developer carrying member and in a region thereof where said developer carrying member is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said magnetic member and said developer carrying member;
• a bearing for rotatably supporting said developer carrying member, said bearing being disposed adjacent the longitudinal end and longitudinally outside said magnetic member;
• and
• an auxiliary sealing member disposed between a position between said magnetic member and said bearing with respect to a longitudinal direction of said developer carrying member.

A developing apparatus, comprising:

• a container for accommodating a developer containing magnetic carrier particles and toner particles, wherein a volume content of such toner particles of the toner particles as has particle sizes satisfying (1/2)M<r<(3/2)M, where M is a volume average particle size of the toner and r is a particle size of a toner particle is not less than 90% by volume, and wherein a content of such a toner particles as has particle sizes satisfying 0<r<2M is not less than 99% by volume, and wherein M is not more than 12 microns;
• `a rotatable developer carrying member, disposed at least partly in said container, for facing an image bearing member at a developing position and for carrying the developer thereon to the developing position;
• a magnet disposed in said developer carrying member, said magnet comprising a plurality of magnets for conveying the developer;
• and
• a magnetic member disposed closely to a circumferential surface of said developer carrying member and in a circumferential direction of said developer carrying member in a region thereof where said developer carrying member is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said magnetic member is magnetized by said magnet, and wherein said magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said magnetic member and said developer carrying member.

A developing apparatus comprising:

• a container for accommodating a developer containing magnetic carrier particles and toner particles, wherein a volume content of such toner particles of the toner particles as has particle sizes satisfying (1/2)M<r<(3/2)M, where M is a volume average particle size of the toner and r is a particle size of a toner particle is not less than 90% by volume, and wherein a content of such a toner particles as has particle sizes satisfying 0<r<2M is not less than 99% by volume, and wherein M is not more than 12 microns;
• `a rotatable developer carrying member, disposed at least partly in said container, for facing an image bearing member at a developing position and for carrying the developer thereon to the developing position;
• a magnet disposed in said developer carrying member;
• a magnetic member disposed closely to and along said developer carrying member in a region thereof where said developer carrying member is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said magnetic member and said developer carrying member;
• a bearing for rotatably supporting said developer carrying member, said bearing being disposed adjacent the longitudinal end and longitudinally outside said magnetic member;
• and
• an auxiliary sealing member disposed between a position between said magnetic member and said bearing with respect to a longitudinal direction of said developer carrying member.

A developing apparatus, comprising:

• a container for accommodating a developer containing magnetic particles;
• a rotatable developer carrying member, disposed at least partly in said container, for facing an image bearing member at a developing position and for carrying the developer thereon to the developing position;
• a magnet disposed in said developer carrying member, said magnet comprising a plurality of magnets for conveying the developer;
• and
• a magnetic member disposed closely to a circumferential surface of said developer carrying member and in a circumferential direction of said developer carrying member in a region thereof where said developer carrying member is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said magnetic member is magnetized by said magnet, and wherein said magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said magnetic member and said developer carrying member;
• wherein said developer carrying member has a rough surface region for carrying the developer to be conveyed to the developing position and a less roughness region to which said magnetic member is faced.

A developing apparatus comprising:

• a container for accommodating a developer containing magnetic particles;
• a rotatable developer carrying member, disposed at least partly in said container, for facing an image bearing member at a developing position and for carrying the developer thereon to the developing position;
• a magnet disposed in said developer carrying member;
• a magnetic member disposed closely to and along said developer carrying member in a region thereof where said developer carrying member is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said magnetic member and said developer carrying member;
• wherein said developer carrying member has a rough surface region for carrying the developer to be conveyed to the developing position and a less roughness region to which said magnetic member is faced;
• a bearing for rotatably supporting said developer carrying member, said bearing being disposed adjacent the longitudinal end and longitudinally outside said magnetic member;
• and
• an auxiliary sealing member disposed between a position between said magnetic member and said bearing with respect to a longitudinal direction of said developer carrying member.

A developing apparatus, comprising:

• a container for accommodating a developer containing magnetic particles;
• a rotatable developer carrying member, at least partly disposed in said container, for facing an image bearing member at a developing position and for carrying thereon a layer of the developer to the developing position;
• a magnet disposed in said developer carrying member, said magnet comprising a plurality of magnets for conveying the developer;
• a first magnetic member disposed closely to a circumferential surface of said developer carrying member and in a circumferential direction of said developer carrying member and disposed closely thereto in a region of said developer carrying member which is in said developer container, adjacent a longitudinal end of said developer carrying member, wherein said first magnetic member is magnetized, and wherein said first magnetic member cooperates with said magnet to form a magnetic field for forming a magnetic brush of the developer in a gap between said first magnetic member and said developer carrying member;
• a second magnetic member extending along a length of said developer carrying member and disposed closely to said developer carrying member at a developer outlet where the developer layer is discharged from said container by said developer carrying member, wherein said second magnetic member is disposed within influence of magnetic field provided by said magnet;
• and
• a third magnetic member disposed closely to said developer carrying member along a length thereof adjacent an inlet where the developer having passed through the developing position is introduced into said container by said developer carrying member, said third magnetic member is within influence of magnetic field by said magnet.

A developing apparatus comprising:

• a container for accommodating a developer containing magnetic particles;
• a rotatable developer carrying member, at least partly disposed in said container, for facing an image bearing member at a developing position and for carrying thereon a layer of the developer to the developing position;
• a magnet disposed in said developer carrying member;
• a first magnetic member extended along a surface of said developer carrying member and disposed closely thereto in a region of said developer carrying member which is disposed in said developer container, adjacent a longitudinal end of said developer carrying member, said first magnetic member is disposed within influence of said magnet;
• a second magnetic member extending along a length of said developer carrying member and disposed closely to said developer carrying member at a developer outlet where the developer layer is discharged from said container by said developer carrying member, wherein said second magnetic member is disposed within influence of magnetic field provided by said magnet;
• and
• a third magnetic member disposed closely to said developer carrying member along a length thereof adjacent an inlet where the developer having passed through the developing position is introduced into said container by said developer carrying member, said third magnetic member is within influence of magnetic field by said magnet;
• a bearing for rotatably supporting said developer carrying member, said bearing being disposed adjacent the longitudinal end and longitudinally outside said first magnetic member;
• and
• an auxiliary sealing member disposed between a position between said first magnetic member and said bearing with respect to a longitudinal direction of said developer carrying member.