Electrophotographic member, method for producing same, process cartridge, and electrophotographic image-forming device

A process cartridge configured to be detachably attachable to an image forming apparatus, the process cartridge comprising an electrophotographic member comprising:

• a mandrel;
• and
• an elastic layer on an outer periphery of the mandrel,
• the elastic layer containing a polyurethane elastomer including a matrix and a plurality of domains dispersed in the matrix,
• a parameter A and a parameter B satisfying a relationship of A<B, where
• the parameter A indicates a viscoelastic term of each of the plurality of domains and the parameter B indicates a viscoelastic term of the matrix, the parameters A and B being measured in a viscoelastic image of a cross-section of the elastic layer in a thickness direction with a scanning probe microscope,
• the elastic layer having a microrubber hardness at a temperature of 23° C. of 20 or more and 50 or less, and
• in an indentation test of the elastic layer with a nanoindenter at 23° C., in which a Vickers indenter is indented into the elastic layer indented into the elastic layer at a load speed of 10 mN/30 sec and is maintained at a load of 10 mN for 60 seconds, followed by unloading, strain after 5 seconds from the unloading being 1 μm or less.

An electrophotographic image forming apparatus comprising an electrophotographic member comprising:

• a mandrel;
• and
• an elastic layer on an outer periphery of the mandrel,
• the elastic layer containing a polyurethane elastomer including a matrix and a plurality of domains dispersed in the matrix,
• a parameter A and a parameter B satisfying a relationship of A<B, where
• the parameter A indicates a viscoelastic term of each of the plurality of domains and the parameter B indicates a viscoelastic term of the matrix, the parameters A and B being measured in a viscoelastic image of a cross-section of the elastic layer in a thickness direction with a scanning probe microscope,
• the elastic layer having a microrubber hardness at a temperature of 23° C. of 20 or more and 50 or less, and
• in an indentation test of the elastic layer with a nanoindenter at 23° C., in which a Vickers indenter is indented into the elastic layer at a load speed of 10 mN/30 sec and is maintained at a load of 10 mN for 60 seconds, followed by unloading, strain after 5 seconds from the unloading being 1 μm or less.

A method of producing an electrophotographic member comprising:

• a mandrel;
• and
• an elastic layer on an outer periphery of the mandrel,
• the elastic layer containing a polyurethane elastomer including a matrix and a plurality of domains dispersed in the matrix,
• a parameter A and a parameter B satisfying a relationship of A<B, where
• the parameter A indicates a viscoelastic term of each of the plurality of domains and the parameter B indicates a viscoelastic term of the matrix, the parameters A and B being measured in a viscoelastic image of a cross-section of the elastic layer in a thickness direction with a scanning probe microscope,
• the elastic layer having a microrubber hardness at a temperature of 23° C. of 20 or more and 50 or less, and
• in an indentation test of the elastic layer with a nanoindenter at 23° C., in which a Vickers indenter is indented into the elastic layer at a load speed of 10 mN/30 sec and is maintained at a load of 10 mN for 60 seconds, followed by unloading, strain after 5 seconds from the unloading being 1 μm or less, the method comprising the steps of:
• (i) allowing a first polyether having at least two isocyanate groups and a first polycarbonate polyol having at least two hydroxy groups to react with each other to provide a urethane reactive emulsifier having at least two hydroxy groups;
• (ii) providing a dispersion in which liquid droplets each containing at least part of the urethane reactive emulsifier are dispersed in a second polycarbonate polyol;
• (iii) mixing the dispersion and a polyisocyanate having at least two isocyanate groups with each other to provide a mixture for forming an elastic layer;
• and
• (iv) allowing the urethane reactive emulsifier, the second polycarbonate polyol, and the polyisocyanate in the mixture for forming an elastic layer to react with each other on a surface of the mandrel, to thereby provide the elastic layer.