Developing member, electrophotographic process cartridge, and electrophotographic image forming apparatus
A developing member includes a substrate, an elastic layer, and a surface layer in that order. The surface layer contains a urethane resin and a filler. The urethane resin has: the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3), between two adjacent urethane linkages; and the structure represented by structural formula (4) and the structure represented by structural formula (5), between two adjacent urethane linkages. The structural formulas (1) to (5) are as follows:
1. A developing member comprising: a substrate, an elastic layer, and a surface layer in that order, the surface layer containing a urethane resin and a filler, the urethane resin having:
the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3), between two adjacent urethane linkages; and
the structure represented by structural formula (4) and the structure represented by structural formula (5), between two adjacent urethane linkages:
wherein in the urethane resin, the proportion of the total number of the structures represented by structural formula (4) and structural formula (5) relative to the total number of the structures represented by structural formulas (1), (2), (3), (4), and (5) is 25% to 75%, and
wherein the proportion of the number of the structures represented by structural formula (4) relative to the total number of the structures represented by structural formula (4) and structural formula (5) is 45% to 95%.
2. The developing member according to claim 1 , wherein in the urethane resin, the proportion of the number of the structures represented by structural formula (4) relative to the total number of the structures represented by structural formula (4) and structural formula (5) is 85% to 95%.
3. The developing member according to claim 1 , wherein the surface layer further contains a conducting agent including a carbon black and an ionic conductive agent.
4. The developing member according to claim 1 , wherein the surface layer further contains silica particles.
5. The developing member according to claim 1 , wherein the urethane resin is a reaction product between
an isocyanate-terminated prepolymer having structures represented by the structural formula (1) and at least one of the structural formulae (2) and (3), and
polycarbonate diol having structures represented by the structural formulae (4) and (5).
6. The developing member according to claim 1 , wherein the urethane resin is not an amine modified urethane resin.
7. A process cartridge capable of removably mounted in an electrophotographic image forming apparatus, the process cartridge comprising: a developing member, a developing blade, and a toner container, the developing member including a substrate, an elastic layer, and a surface layer in that order, the surface layer containing a urethane resin and a filler, the urethane resin having:
the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3), between two adjacent urethane linkages; and
the structure represented by structural formula (4) and the structure represented by structural formula (5), between two adjacent urethane linkages:
wherein in the urethane resin, the proportion of the total number of the structures represented by structural formula (4) and structural formula (5) relative to the total number of the structures represented by structural formulas (1), (2), (3), (4), and (5) is 25% to 75%, and
wherein the proportion of the number of the structures represented by structural formula (4) relative to the total number of the structures represented by structural formula (4) and structural formula (5) is 45% to 95%.
8. An electrophotographic image forming apparatus comprising: a photosensitive member, and a developing member disposed so as to charge the photosensitive member, the developing member including a substrate, an elastic layer, and a surface layer in that order, the surface layer containing a urethane resin and a filler, the urethane resin having:
the structure represented by structural formula (1) and at least one of the structures represented by structural formula (2) and structural formula (3), between two adjacent urethane linkages; and
the structure represented by structural formula (4) and the structure represented by structural formula (5), between two adjacent urethane linkages:
wherein in the urethane resin, the proportion of the total number of the structures represented by structural formula (4) and structural formula (5) relative to the total number of the structures represented by structural formulas (1), (2), (3), (4), and (5) is 25% to 75%, and
wherein the proportion of the number of the structures represented by structural formula (4) relative to the total number of the structures represented by structural formula (4) and structural formula (5) is 45% to 95%.