Cleaning blade member

1. A cleaning blade member comprising a polyurethane formed by using a polyol consisting essentially of a polycarbonatediol, a polyisocyanate consisting essentially of 4,4′-diphenylmethane diisocyanate (MDI), and a crosslinking agent containing a short chain diol and a triol, wherein the proportion of the polyisocyanate is 40 to 50 parts by weight based on 100 parts by weight of the polyurethane, and, said polyurethane having a tensile strength at 60° C. of 200 kg/cm 2 or higher, and a tensile strength retention ΔT, represented by the following equation, of 40% or more:

Δ T (%)= T 60 /T 10 ×100

where T 10 denotes a tensile strength at 10° C., and T 60 denotes the tensile strength at 60° C.

2. The cleaning blade member according to claim 1 , wherein the polyurethane has a tensile strength at 300% elongation at 60° C. of 200 kg/cm 2 or higher.

3. The cleaning blade member according to claim 1 , wherein the polyurethane has a peak temperature at tan δ (1 Hz) of 10° C. or lower.

4. The cleaning blade member according to claim 1 , wherein the short chain diol and the triol are at such a weight ratio that the short chain diol:triol=50:50 to 95:5.

5. The cleaning blade member according to claim 1 , which has an α value of 0.7 to 1.0.

6. The cleaning blade member according to claim 1 , which further uses a curing retarder.

7. The cleaning blade member according to claim 2 , wherein the polyurethane has a peak temperature at tan δ (1 Hz) of 10° C. or lower.

8. The cleaning blade member according to claim 2 , wherein the short chain diol and the triol are at such a weight ratio that the short chain diol:triol=50:50 to 95:5.

9. The cleaning blade member according to claim 3 , wherein the short chain diol and the triol are at such a weight ratio that the short chain diol:triol=50:50 to 95:5.