Developing device frame unit, developing device, process cartridge, and manufacturing method of the developing device frame unit

A developing apparatus for developing an electrostatic latent image formed on an image bearing member, said apparatus comprising:

• (i) a developer carrying member configured to develop the electrostatic latent image with a developer.
• (ii) a developer accommodating portion configured to accommodate the developer;
• (iii) a regulating member configured to regulate the layer thickness of the developer on said developer carrying member;
• and
• (iv) a developing device frame unit, including
• a developing device frame including a seal forming portion,
• a one end sealing member which is provided at one longitudinal end of said developing device frame and which is contactable to a surface of said developer carrying member to prevent the developer from leaking from said developing device frame unit in an axial direction of said developer carrying member when said developer carrying member is mounted to said developing device frame unit,
• an other end sealing member which is provided at the other longitudinal end of said developing device frame and which is contactable to the surface of said developer carrying member to prevent the developer from leaking from said developing device frame unit in an axial direction of said developer carrying member when said developer carrying member is mounted to said developing device frame unit,
• a blade sealing member configured to provide a seal between said regulating member and said developing device frame to prevent the developer from leaking out of said developing device frame unit when said regulating member is mounted to said developing device frame unit, wherein said blade sealing member comprises an elastomer resin material which is injection-molded with a metal mold and which is provided in said seal forming portion where said one end sealing member and said other end sealing member are provided, said blade sealing member connecting said one end sealing member and said other end sealing member with each other, and
• a protrusion provided by a squeezed-out portion of the elastomer resin material, wherein the squeezed-out portion is provided by injecting, into a space defined by the metal mold, said seal forming portion, said one end sealing member and the other end sealing member, a volume of the elastomer resin material that is larger than the volume of the space.

A process cartridge detachably mountable to a main assembly of an image forming apparatus, said process cartridge comprising;

• (i) an image bearing member;
• (ii) a developer carrying member configured to develop an electrostatic latent image formed on said image bearing member with a developer;
• (iii) a developer accommodating portion configured to accommodate the developer;
• (iv) a regulating member configured to regulate the layer thickness of the developer on said developer carrying member;
• and
• (v) a developing device frame unit, including
• a developing device frame including a seal forming portion,
• a one end sealing member which is provided at one longitudinal end of said developing device frame and which is contactable to a surface of said developer carrying member to prevent the developer from leaking from said developing device frame unit in an axial direction of said developer carrying member when said developer carrying member is mounted to said developing device frame unit,
• an other end sealing member which is provided at the other longitudinal end of said developing device frame and which is contactable to the surface of said developer carrying member to prevent the developer from leaking from said developing device frame unit in an axial direction of said developer carrying member when said developer carrying member is mounted to said developing device frame unit,
• a blade sealing member configured to provide a seal between said regulating member and said developing device frame to prevent the developer from leaking out of said developing device frame unit when said regulating member is mounted to said developing device frame unit, wherein said blade sealing member comprises an elastomer resin material which is injection-molded with a metal mold and which is provided in said seal forming portion where said one end sealing member and said other end sealing member are provided, said blade sealing member connecting said one end sealing member and said other end sealing member with each other, and
• a protrusion provided by a squeezed-out portion of the elastomer resin material, wherein the squeezed-out portion is provided by injecting, into a space defined by the metal mold, said seal forming portion, said one end sealing member and said other end sealing member, a volume of the elastomer resin material that is larger than the volume of the space.

A manufacturing method for a developing device frame unit comprising:

• a step of mounting a first end sealing member which is provided at one longitudinal end of a developing device frame of a developing device frame unit and which is contactable to a surface of a developer carrying member mountable on the developing device frame unit to prevent the developer from leaking from the developing device frame unit in an axial direction of the developer carrying member when the developer carrying member is mounted on the developing device frame unit;
• a step of mounting a second end sealing member which is provided at the other longitudinal end of the developing device frame and which is contactable to the surface of the developer carrying member to prevent the developer from leaking from the developing device frame unit in an axial direction of the developer carrying member when the developer carrying member is mounted on the developing device frame unit;
• and
• a sealing member molding step of molding a blade sealing member configured to provide a seal between the regulating member and the developing device frame to prevent the developer from leaking from the developing device frame unit when the regulating member is mounted on the developing device frame unit, wherein the blade sealing member comprises an elastomer resin material which is injection-molded with a metal mold and which is provided in a seal forming portion of the developing device frame where the first end sealing member and the second end sealing member are provided, the blade sealing member connecting the first end sealing member and the second end sealing member with each other, said sealing member molding step including the step of providing a protrusion provided by a squeezed-out portion of the elastomer resin material, wherein the squeezed-out portion is provided by injecting, into a space defined by the metal mold, the seal forming portion, the first end sealing member and the second end sealing member, a volume of the elastomer resin material that is larger than the volume of the space.