Pressure-Controlled Steam Oven For Asymptotic Temperature Control Of Continuous Feed Media

A vapor fuser apparatus for fusing a toner material to a substrate in a xerographic system, the vapor fuser apparatus comprising:

• a vapor oven defining a gas-tight pressure chamber and having sealed entry and exit ports for transferring said substrate through the pressure chamber;
• and
• means for controlling an internal pressure inside pressure chamber such that a saturation temperature of heat transfer fluid disposed inside the pressure chamber is adjusted to a predetermined temperature, wherein said internal pressure inside pressure chamber is different from an atmospheric pressure external to said steam oven.

A method for fusing a toner material onto a substrate in a xerographic system, the method comprising:

• generating temperature and pressure conditions inside a pressure chamber containing a heat transfer fluid such that an internal pressure of heat transfer vapor in said pressure chamber is different from an atmospheric pressure external to said pressure chamber, and such that a temperature of said pressure chamber is equal to or greater than a boiling point temperature of said heat transfer fluid at said pressure conditions, and
• transferring said substrate with un-fused toner material disposed thereon through said pressure chamber without significantly changing a pressure differential between said internal pressure and said atmospheric pressure, whereby said substrate is heated to said internal temperature and said toner material is fused to said substrate.