A fuser includes a magnetic flux generation unit to generate a magnetic
flux, a heating member which is heated by electromagnetic induction of
the magnetic flux, a fuser member to contact the heating member and heat
a toner image so as to fuse the toner image onto a recording medium, a
detection unit to directly or indirectly detect a contacting state of the
fuser member at an edge in a width direction of the fuser member with the
heating member, and a magnetic flux adjusting member to reduce the
magnetic flux acting upon an end in the width direction of the heating
member in accordance with a detection result of the detection unit.