Developing unit and image forming apparatus

A developing unit that develops a latent image carried on a latent image carrier of an image forming apparatus, comprising:

• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and
• a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnetic force generator is constituted in such a manner that a peak point of magnetic flux density on the moving surface in a direction parallel to the moving surface between a restricting magnetic pole that is arranged closest to the restricting member and an upstream adjacent magnetic pole that is arranged so as to be adjacent to the restricting magnetic pole on an upstream side of the developer carrier in a direction of movement of the moving surface is positioned on a downstream side in the direction of movement of the moving surface than a point where the magnetic force density in a normal direction to the moving surface formed by opposite magnetic poles becomes zero, wherein
• the restricting magnetic pole is provided in a restricting magnet,
• the upstream adjacent magnetic pole is provided in an upstream adjacent magnet arranged so as to be adjacent to the restricting magnet on an upstream side in the direction of movement of the moving surface, and
• a first surface of the restricting magnet toward the moving surface and a second surface of the restricting magnet toward an adjacent magnet that is arranged so as to be adjacent to an upstream side of the developer carrier in a direction of movement of the moving surface and has an upstream adjacent magnetic pole forming a ridged corner portion, and
• the ridged corner portion is chamfered.

An image forming apparatus comprising:

• a latent image carrier that carries a latent image;
• and
• a developing unit that develops the latent image carried on the latent image carrier, wherein the developing unit includes
• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and
• a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnets includes a restricting magnet that is arranged closest to the restricting member and has a restricting magnetic pole,
• a first surface of the restricting magnet toward the moving surface and a second surface of the restricting magnet toward an upstream adjacent magnet that is arranged so as to be adjacent to an upstream side of the developer carrier in a direction of movement of the moving surface and has an upstream adjacent magnetic pole forming a ridged corner portion, and
• the ridged corner portion is chamfered.

A developing unit that develops a latent image carried on a latent image carrier of an image forming apparatus, comprising:

• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and
• a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnetic force generator is constituted in such a manner that a peak point of magnetic flux density on the moving surface in a direction parallel to the moving surface between a restricting magnetic pole that is positioned so as to face the restricting member and an upstream adjacent magnetic pole that is arranged so as to be adjacent to the restricting magnetic pole on an upstream side of the developer carrier in a direction of movement of the moving surface is positioned on a downstream side in the direction of movement of the moving surface than a point where the magnetic force density in a normal direction to the moving surface formed by opposite magnetic poles becomes zero.

A developing unit that develops a latent image carried on a latent image carrier of an image forming apparatus, comprising:

• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnetic force generator is constituted in such a manner that a peak point of magnetic flux density on the moving surface in a direction parallel to the moving surface between a restricting magnetic pole that is arranged closest to the restricting member and an upstream adjacent magnetic pole that is arranged so as to be adjacent to the restricting magnetic pole on an upstream side of the developer carrier in a direction of movement of the moving surface is positioned on a downstream side in the direction of movement of the moving surface than a point where the magnetic force density in a normal direction to the moving surface formed by opposite magnetic poles becomes zero, wherein
• at least a portion of the restricting member is formed by magnetic material or a magnetic member made of the magnetic material is fixed to the restricting member, and
• at least one conveying magnetic pole that restricts and conveys the developer on the surface of the developer carrier is provided between a pumping magnetic pole for attracting and pumping the developer from the developer containing unit onto the developer carrier and the upstream adjacent magnetic pole in the direction of movement of the moving surface.

An image forming apparatus comprising:

• a latent image carrier that carries a latent image;
• and
• a developing unit that develops the latent image carried on the latent image carrier, wherein the developing unit includes
• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and
• a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnetic force generator is constituted in such a manner that a peak point of magnetic flux density on the moving surface in a direction parallel to the moving surface between a restricting magnetic pole that is positioned so as to face the restricting member and an upstream adjacent magnetic pole that is arranged so as to be adjacent to the restricting magnetic pole on an upstream side of the developer carrier in a direction of movement of the moving surface is positioned on a downstream side in the direction of movement of the moving surface than a point where the magnetic force density in a normal direction to the moving surface formed by opposite magnetic poles becomes zero.

An image forming apparatus comprising:

• a latent image carrier that carries a latent image;
• and
• a developing unit that develops the latent image carried on the latent image carrier, wherein the developing unit includes
• a developer containing unit that contains developer;
• a developer carrier that has a moving surface, and carries the developer on the moving surface;
• a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets arranged along the moving surface;
• and
• a restricting member that restricts a layer thickness of the developer carried on the moving surface, wherein,
• the magnetic force generator is constituted in such a manner that a peak point of magnetic flux density on the moving surface in a direction parallel to the moving surface between a restricting magnetic pole that is arranged closest to the restricting member and an upstream adjacent magnetic pole that is arranged so as to be adjacent to the restricting magnetic pole on an upstream side of the developer carrier in a direction of movement of the moving surface is positioned on a downstream side in the direction of movement of the moving surface than a point where the magnetic force density in a normal direction to the moving surface formed by opposite magnetic poles becomes zero, wherein
• the restricting magnetic pole is provided in a restricting magnet,
• the upstream adjacent magnetic pole is provided in an upstream adjacent magnet arranged so as to be adjacent to the restricting magnet on an upstream side in the direction of movement of the moving surface, and
• a first surface of the restricting magnet toward the moving surface and a second surface of the restricting magnet toward an adjacent magnet that is arranged so as to be adjacent to an upstream side of the developer carrier in a direction of movement of the moving surface and has an upstream adjacent magnetic pole forming a ridged corner portion, and
• the ridged corner portion is chamfered.