Elastomeric Roll for an Electrophotographic Image Forming Device having Compressible Hollow Microparticles Defining a Surface Texture of the Roll

Abstract

A roll for use in an electrophotographic image forming device according to one example embodiment includes an elastomeric core having hollow microparticles dispersed within the core. The hollow microparticles are compressive and resiliently recoverable after receiving an applied force. Portions of at least some of the hollow microparticles extend beyond an outer circumference of the core and provide a surface texture to the core.

1 . A roll for use in an electrophotographic image forming device, comprising an elastomeric core having hollow microparticles dispersed within the core, the hollow microparticles being compressive and resiliently recoverable after receiving an applied force, portions of at least some of the hollow microparticles extending beyond an outer circumference of the core providing a surface texture to the core. 
     
     
         2 . The roll of  claim 1 , wherein the roll is a developer roll configured to supply toner to a photoconductive member in the electrophotographic image forming device. 
     
     
         3 . The roll of  claim 1 , wherein the elastomeric core is a conductive or semi-conductive soft rubber. 
     
     
         4 . The roll of  claim 3 , wherein the soft rubber includes at least one of silicone rubber, nitrile rubber, an ethylene propylene copolymer, polybutadiene, styrene-co-butadiene, isoprene rubber and polyurethane. 
     
     
         5 . The roll of  claim 4 , wherein the soft rubber includes polyurethane having an isocyanate portion and a polyol portion, the isocyanate portion includes at least one of toluene diisocyanate (TDI), polymeric TDI, diphenylmethane diisocyanate (MDI), polymeric MDI, dicyclohexylmethane diisocyanate (H 12 MDI), polymeric H 12 MDI, isophorone diisocyanate (IPDI), polymeric IPDI, 1,6-hexamethylene diisocyanate (HDI) and polymeric HDI, and the polyol portion includes at least one of polyether, polyester and polybutadiene. 
     
     
         6 . The roll of  claim 3 , wherein the elastomeric core includes at least one of an ionic conductive additive, an inherently conductive polymer, carbon black, carbon nanoparticles, carbon fibers and graphite. 
     
     
         7 . The roll of  claim 1 , wherein a median size of the hollow microparticles is between 1 μm and 100 μm. 
     
     
         8 . The roll of  claim 1 , wherein a difference between the tenth percentile particle size of the hollow microparticles and the ninetieth percentile particle size of the hollow microparticles does not exceed one and a half times a median particle size of the hollow microparticles. 
     
     
         9 . The roll of  claim 1 , wherein the hollow microparticles dispersed within the core include a first set of hollow microparticles having a first size and a second set of hollow microparticles having a second size, wherein a difference between the tenth percentile particle size of the hollow microparticles and the ninetieth percentile particle size of each of the first and second sets of hollow microparticles does not exceed one and a half times a median particle size of the respective set of hollow microparticles. 
     
     
         10 . The roll of  claim 1 , wherein the hollow microparticles are compressible and substantially recoverable under a pressure of 0.1 bars to 10 bars. 
     
     
         11 . The roll of  claim 1 , wherein no coating is present on an outer surface of the elastomeric core. 
     
     
         12 . The roll of  claim 1 , further comprising a coating having no hollow microparticles on an outer surface of the elastomeric core. 
     
     
         13 . The roll of  claim 1 , wherein the core has a surface roughness Ra of between 0.1 μm and 5.0 μm. 
     
     
         14 . The roll of  claim 1 , wherein the core has a surface roughness Rz of between 0.1 μm and 25 μm. 
     
     
         15 . A method for forming a roll core for use in an electrophotographic image forming device, comprising:
 shaping the roll core from a mixture of an uncured elastomer and hollow microparticles;   curing the elastomer of the shaped roll core without permanently expanding hollow microparticles positioned near the outer surface of the shaped roll core; and   after curing, permanently expanding the hollow microparticles positioned near the outer surface of the shaped roll core to form the roll core having compressible and resiliently recoverable hollow microparticles extending beyond an outer circumference of the roll core and providing a surface texture to the roll core.   
     
     
         16 . The method of  claim 15 , wherein shaping the roll core from the mixture of the uncured elastomer and hollow microparticles includes loading the mixture of the uncured elastomer and hollow microparticles into a mold cavity. 
     
     
         17 . The method of  claim 16 , wherein curing the elastomer of the shaped roll core without permanently expanding the hollow microparticles positioned near the outer surface of the shaped roll core includes heating the mixture of the uncured elastomer and hollow microparticles in the mold cavity to at least a temperature sufficient to cure the elastomer but not sufficient to permanently expand the hollow microparticles positioned near the outer surface of the shaped roll core. 
     
     
         18 . The method of  claim 17 , wherein permanently expanding the hollow microparticles positioned near the outer surface of the shaped roll core includes removing the shaped roll core from the mold cavity and then heating the outer surface of the shaped roll core to at least a temperature sufficient to permanently expand the hollow microparticles. 
     
     
         19 . The method of  claim 18 , wherein heating the outer surface of the shaped roll core to at least a temperature sufficient to permanently expand the hollow microparticles includes heating the outer surface of the shaped roll core to between 80° C. and 175° C.