Development roller and blade used in development device, and development device and image-forming device having the development roller and blade

A development roller comprising:

• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating that is provided on a periphery of the base material, and includes two or more layers, and a coating layer provided inside an outermost coating layer has a higher charging capability to a developing agent than at least the outermost coating layer,
• wherein the coating layer inside the outermost coating layer is made of silicon, and the outermost coating layer is made of polystryene.

A development roller comprising:

• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating that is provided on a periphery of the base material, and includes two or more coating layers, and a coating layer provided inside an outermost coating layer has a higher charging capability to a developing agent than at least the outermost coating layer,
• wherein the coating layer inside the outermost coating layer has a layer thickness of about 10 μm, and is made of silicon,
• wherein the outermost coating layer has a layer thickness of 1 through 2 μm, and is made of polystyrene.

A development roller comprising:

• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating provided on a periphery of the base material,
• wherein the layered coating includes:
• a first coating layer;
• and
• a second coating layer located outside the first coating layer, a concentration of a charge control agent added to the second coating layer being lower than that added to the first coating layer.

A development roller comprising:

• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating that is provided on a periphery of the base material, and includes a first coating layer, and a second coating layer located outside the first coating layer, a concentration of a charge control agent added to the second coating layer being lower than that added to the first coating layer,
• wherein the concentration of the charge control agent added to the first coating layer is 3 wt %, and the concentration of the charge control agent added to the second coating layer is 0 wt %.

A development roller comprising:

• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating that provided on a periphery of the base material, and includes a first coating layer, and a second coating layer located outside the first coating layer, a concentration of a charge control agent added to the second coating layer being lower than that added to the first coating layer,
• wherein the concentration of the charge control agent added to the first coating layer which has a layer thickness of about 10 μm is 3 wt %, and the concentration of the charge control agent added to the second coating layer which has a layer thickness of 1 through 2 μm and is 0 wt %.

A blade comprising:

• a base material made of metal and shaped like a plate;
• and
• a layered coating provided on one surface of the base material, the surface being in contact with a development roller,
• wherein the layered coating includes two or more layers, and a coating layer provided at least inside an outermost coating layer has a higher charging capability to a developing agent than the outermost coating layer.

A development device comprising:

• a development roller;
• and
• a blade that is brought into contact with the development roller, and forms a toner layer at a predetermined layer thickness,
• wherein the development roller comprises:
• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating provided on a periphery of the base material,
• wherein the layered coating includes two or more layers, and a coating layer provided at least inside an outermost coating layer has a higher charging capability to a developing agent than the outermost coating layer.

A development device comprising:

• a development roller;
• and
• a blade that is brought into contact with the development roller, and forms a toner layer at a predetermined layer thickness,
• wherein the blade comprises:
• a base material made of metal and shaped like a plate;
• and
• a layered coating provided on one surface of the base material, the surface being in contact with said development roller,
• wherein the layered coating includes two or more layers, and a coating layer provided at least inside an outermost coating layer has a higher charging capability to a developing agent than the outermost coating layer.

An image-forming device comprising:

• a photosensitive body;
• a charger that charges the photosensitive body;
• an exposure part that exposes the photosensitive body charged by the charger to light, and forms an electrostatic latent image;
• a development device that develops the photosensitive body exposed to light, and visualizes the electrostatic latent image into a toner image;
• and
• a transfer part that transfers the toner image onto a recordable medium,
• wherein the development device comprises:
• a development roller;
• and
• a blade that is brought into contact with the development roller, and forms a toner layer at a predetermined layer thickness,
• wherein the development roller comprises:
• a shaft;
• a base material that coats a periphery of the shaft, and is made of a resistance body;
• and
• a layered coating provided on a periphery of the base material,
• wherein the layered coating includes two or more layers, and a coating layer provided at least inside an outermost coating layer has a higher charging capability to a developing agent than the outermost coating layer.