Fixing apparatus including apparatus for controlling the supply of

Abstract

A fixing apparatus for controlling an oil transfer apparatus to maintain a releasing agent holding layer such that it is not always saturated with the releasing agent. This makes it a compact, cost-effective unit with a long service life and provides a uniform, stable oil coating that eliminates image noise problems. In order to use a constant and minimum necessary amount of releasing agent, a releasing agent supply nozzle is incorporated with multiple protrusive or retrusive droplet growth assisting members at or near multiple releasing agent discharge ports. The supply nozzle used for supplying the oil has multiple discharge holes having approximately equal opening cross-sectional areas and an equalizing member which equalizes the amount of oil discharged from each discharge hole. The outer diameter D1 of the oil supply roller, the outer diameter D2 of the metal core and the distance P of adjacent through-holes formed on the periphery of the metal core satisfy a relation, 0.6<D1.multidot.(D1-D2)/(D2.multidot.P)<6. A quantifying apparatus is provided to equalize the amount of oil transferred by the oil pump when it is intermittently transferred. The quantifying apparatus contributes in achieving a constant amount of releasing agent coating. A releasing agent leakage prevention member is provided to prevent unnecessary oil leakage from the releasing agent supply nozzle and rollers. A specific correlation is established between the centerline average roughness of the oil supply roller surface and the amount of the releasing agent supply to the fixing roller by the oil supply roller. This makes it possible to achieve a uniform coating with excellent releasing capability and prevents adhesion of add particles.