Developing blade and its manufacturing method

1. A developing blade, comprising:

a support member; and

a blade member located on one surface of said support member along one side edge of said support member, wherein,

said support member has a coefficient of elasticity in a range of 0.5×10 4 to 4.0×10 4 kg/mm 2 and a moment of inertia of area (Iz) in a range of 6.5E-04 to 1.2E-02,

said blade member is made of a rubber material having a 25% modulus of no greater than 0.85 MPa and has a moment of inertia of area (Iz) in a range of 8E-02 to 1.2E+01, and

said blade member has a warping of no greater than 10 mm in a longitudinal direction.

2. The developing blade according to claim 1 , wherein said support member is made of stainless steel and has a thickness of 0.07 to 0.2 mm and a width of 12 to 30 mm.

3. The developing blade according to claim 1 , wherein said support member is made of phosphor bronze and has a thickness of 0.2 to 0.4 mm and a width of 12 to 30 mm.

4. The developing blade according to claim 1 , wherein,

said blade member comprises a blade body and a skirt positioned at least at one end of a side edge of said blade body facing away from said side edge of said support member, and

an area of contact of said blade member with a developing roller defines a curved surface.

5. The developing blade according to claim 1 , wherein,

said blade member comprises a blade body and a skirt formed along the side edge of said blade body facing away from said side edge of said support member, and

an area of contact of said blade member with a developing roller defines a curved surface.

6. The developing blade according to claim 1 , wherein said side edge of said support member extends 0.02 to 2 mm out of a top end of said blade member.

7. The developing blade according to claim 6 , wherein said support member has at a peripheral edge a minute projection jutting toward a surface having said blade member.

8. A method for manufacturing a developing blade comprising a blade member along one side edge of a support member, comprising:

using as the support member a material having a coefficient of elasticity in a range of 0.5×10 4 to 4.0×10 4 kg/mm 2 and a moment of inertia of area (Iz) in a range of 6.5E-04 to 1.2E-02;

using as the blade member a rubber material having a 25% modulus of no greater than 0.85 MPa and having a moment of inertia of area (Iz) in a range of 8E-02 to 1.2E+01; and

using a mold comprising:

a top mold surface with a cavity formed for the formation of the blade member and a gate in communication with said cavity; and

a bottom mold having a flat mold surface, wherein

while said cavity is closed up with said support member and a neighborhood of said side edge of said support member is held between an edge of said cavity in the top mold and the bottom mold, the top and bottom molds are brought in alignment and clamped together, so that a molding material is poured from said gate into said cavity.

9. The developing blade manufacturing method according to claim 8 , wherein a portion 0.02 to 2 mm away from said side edge of said support member is held between the edge of said cavity in the top mold and the bottom mold.

10. The developing blade manufacturing method according to claim 8 , wherein,

said support member has a minute projection at a side edge of one surface, and

said support member is held while the surface having said minute projection faces the mold surface of said top mold.