Method for manufacturing open cell rubber material and method for manufacturing rubber roller

A method for manufacturing a rubber roller having a metal shaft and an elastic rubber layer provided on an outer peripheral surface of the metal shaft, comprising the steps of:

• cutting a predetermined length of a cylindrical hollow rubber tube made of a continuous cell rubber material containing a large number of independent cells which are isolated by separation walls between adjacent ones of the cells,
• producing a rubber roller having a continuous cell rubber layer by inserting a metal shaft coated with an adhesive layer in the cylindrical hollow rubber tube,
• grinding the outer periphery of the rubber layer to remove the surface skin layer formed thereon,
• compressing the cells in the continuous cell rubber layer by increasing the pressure in a chamber in which the rubber roller from which the coating layer has been removed is located, and
• decompressing the chamber rapidly to thereby expand the compressed cells rapidly whereby holes or cracks are formed in the separation walls between the adjacent cells,
• whereby the cells contained in the continuous cell rubber layer are at least partly transformed into pores which are connected to the atmosphere through the holes or cracks.

A method for manufacturing a pressure roller having a metal shaft used in a heat roll fixing device, comprising the steps of:

• producing a silicone rubber roller having a silicone rubber layer by inserting a metal shaft coated with an adhesive layer in a cylindrical hollow tube of a continuous cell silicone rubber having a large number of independent cells isolated by separation walls between adjacent ones of the cells,
• grinding an outer periphery of the silicone rubber layer to remove a surface skin layer,
• compressing the cells in the continuous cell silicone rubber layer by increasing the pressure in a chamber in which the silicone rubber roller from which the skin layer has been removed is located,
• decompressing the chamber rapidly to thereby expand the compressed cells rapidly whereby holes or cracks are formed in the separation walls between the adjacent cells due to the rapid expansion,
• whereby the cells contained in the continuous cell silicone rubber layer are at least partly transformed into pores which are connected to the atmosphere through the holes or cracks,
• and attaching a fluororesin tube or forming a fluororesin coating layer onto the outer periphery of the silicone rubber layer having therein pores.

A method for manufacturing an oil supply roller having a metal shaft, and a silicone rubber layer formed on an outer periphery of the metal shaft and having a large number of pores connecting to the atmosphere, each pore being filled with a releasing agent, comprising the steps of:

• producing a silicone rubber roller having a silicone rubber layer by inserting a metal shaft coated with an adhesive layer in a cylindrical hollow tube of a continuous cell silicone rubber having a large number of independent cells isolated by separation walls,
• grinding the silicone rubber layer to remove the surface skin layer formed on the outer periphery thereof,
• compressing the cells in the continuous cell silicone rubber layer by increasing the pressure in a chamber in which the silicone rubber roller from which the skin layer has been removed is located,
• decompressing the chamber rapidly to thereby expand the compressed cells rapidly whereby holes or cracks are formed in the separation walls between the adjacent cells due to the rapid expansion,
• whereby the cells contained in the continuous cell silicone rubber layer are at least partly transformed into pores which are connected to the atmosphere through the holes or cracks, and
• filling the pores formed in the silicone rubber layer with silicone oil.

A method for manufacturing a toner supply roller having a metal shaft, and an elastic rubber layer formed on an outer periphery of the metal shaft and having a large number of pores connecting to the atmosphere, said toner supply roller being used to supply a toner to a developing roller, comprising the steps of:

• producing an elastic rubber roller having a continuous cell elastic rubber layer by inserting a metal shaft coated with an adhesive layer in a cylindrical hollow tube of a continuous cell rubber,
• grinding the continuous cell rubber layer to remove the surface skin layer formed on the outer periphery thereof,
• compressing the independent cells in the continuous cell elastic rubber layer by increasing the pressure in a chamber in which the elastic rubber roller from which the surface skin layer has been removed is located, and
• decompressing the chamber rapidly to thereby expand the compressed cells rapidly whereby holes or cracks are formed in separation walls between the adjacent cells due to the rapid expansion,
• whereby the independent cells contained in the continuous cell elastic rubber layer are at least partly transformed into pores which are connected to the atmosphere through the holes or cracks.