Process for producing an endless belt

Abstract

A method for producing an endless belt for electrophotography by melt-extruding a thermoplastic resin having a diphenyl sulfone structure represented by the following Formula (1) from a circular die to produce the endless belt continuously

What is claimed is:  
     
         1 . A process for producing an endless belt for electrophotography, the process comprising the step of melt-extruding a thermoplastic resin having a diphenyl sulfone structure represented by the following Formula (1) from a circular die to produce the endless belt continuously  
       
         
           
           
               
               
           
         
       
     
     
         2 . The process according to  claim 1 , wherein said thermoplastic resin having a diphenyl sulfone structure is a thermoplastic resin having a structural unit represented by the following Formula (2) or (3)  
       
         
           
           
               
               
           
         
       
     
     
         3 . The process according to  claim 1 , wherein said endless belt has a thickness of from 40 μm to 300 μm.  
     
     
         4 . The process according to  claim 1 , wherein said endless belt has a thickness not larger than ⅓ of the slit width of the circular die used.  
     
     
         5 . The process according to  claim 1 , wherein said endless belt has a thickness not larger than ⅕ of the slit width of the circular die used.  
     
     
         6 . The process according to  claim 1 , wherein said endless belt has an external diameter of from 50% to 400% of the external diameter of the die slit of the circular die used.  
     
     
         7 . The process according to  claim 1 , wherein said endless belt has an external diameter of from more than 100% to 400% or less of the external diameter of the die slit of the circular die used.  
     
     
         8 . The process according to  claim 1 , wherein said endless belt has an external diameter of from 105% to 400% of the external diameter of the die slit of the circular die used.  
     
     
         9 . The process according to  claim 1 , wherein said endless belt has a resistance of from 1×10 0 Ω to 1×10 14Ω.    
     
     
         10 . The process according to  claim 1 , wherein said endless belt has a maximum value of a surface-direction resistance that is not greater than 100 times a minimum value of said surface-direction resistance.  
     
     
         11 . The process according to  claim 1 , wherein said endless belt has a maximum value of a thickness-direction resistance that is not greater than 100 times a minimum value of said thickness-direction resistance.  
     
     
         12 . The process according to  claim 1 , wherein said endless belt is an intermediate transfer belt.  
     
     
         13 . The process according to  claim 1 , wherein said endless belt is a transfer material carrying belt.  
     
     
         14 . The process according to  claim 1 , wherein a gas is blown to the inside of a cylindrical film of the thermoplastic resin melt-extruded from the circular die, to make the endless belt have an external diameter larger than the external diameter of the die slit of the circular die.  
     
     
         15 . The process according to  claim 1 , wherein an extrusion material to be melt-extruded, which contains the thermoplastic resin having a diphenyl sulfone structure, has a breaking extension of 2% or more.  
     
     
         16 . The process according to  claim 1 , wherein an extrusion material to be melt-extruded, which contains the thermoplastic resin having a diphenyl sulfone structure, has a tensile breaking strength of 40 MPa or above.