Fixing devices for fixing marking material to a substrate, printing apparatuses and methods of fixing marking material to a substrate are provided. An exemplary embodiment of the fixing devices includes a first roll including an outer surface; a second roll forming a fixing nip with the outer surface of the first roll at which is received a pre-heated substrate on which marking material is disposed; a release agent applicator system including a supply of a release agent having a viscosity of from about 10 cST to about 300 cST, and a release agent applicator for applying the release agent to the outer surface of the first roll; and a thermal energy source for heating the outer surface of the first roll to a temperature of less than a boiling point of the release agent. The first roll and second roll are operable to apply heat and a pressure of at least about 500 psi to the pre-heated substrate and marking material at the fixing nip to fix the marking material to the substrate.