A protective layer forming device includes lubricant including fatty acid metal salt and a lubricant application blade. The lubricant application blade includes a contact portion contacting a surface of an image bearer to apply the lubricant on the surface of the image bearer. The contact portion includes polyurethane elastomer that includes a reaction product of polytetramethylene ether glycol, aromatic isocyanate, and amine. The contact portion has a Martens hardness of 5.0 N/mm.sup.2 or more and 30.0 N/mm.sup.2 or less. The lubricant applied to the surface of the image bearer by the lubricant application blade has a normalized ionic strength A of a metal ion amount derived from the fatty acid metal salt, satisfying a following expression (1),

[00001]$\begin{array}{cc}1E-4<A<20E-4,& \left(1\right)\end{array}$

where the normalized ionic strength A is measured by a time-of-flight secondary ion mass spectrometer.