A developing method of the present invention is practicable with a developing
unit
of the type including a rotatable, nonmagnetic sleeve and a rigid metering member.
A two ingredient type developer made up of magnetic carrier grains and toner grains
is magnetically deposited on the sleeve. The metering member meters the amount
of the developer deposited on the sleeve. The sleeve has surface roughness Rz ranging
from 5 m to 20 m. The carrier grains each are covered with a coating
layer containing at least binder resin and grains. The ratio of the diameter D
of the individual grain contained in the coating layer to the thickness h of the
binder resin layer lies in the range of 1D/h10. The carrier grains
have a weight-mean grain size ranging from 20 m to 60 m.
