The marking 18 K.R. on the cap, barrel or trim of old fountain pens does not stand for solid gold but for rolled gold: K.R. is the abbreviation for rolled gold, read in Italian markings as karato rolled, that is, a layer of gold of 18 carat fineness rolled onto a base metal. Parts of this kind are the equivalent of gold-filled work. Only a nib with a marking such as 585 or 750 is actually made of gold.
Pens inscribed Imperial were, according to collectors, mostly made in Italy around 1930 and belong to the many small brands of the period about which almost nothing is documented today. They are usually safety pens, on which the nib is wound out of the barrel for writing by turning the knob at the end and retracted again before the cap is screwed down tight.
Value depends heavily on condition: in the mid-2000s a fully restored example ready to write was put at around 200 euros, an unrestored one at considerably less. It is also worth remembering that old pens frequently turn up in boxes that are not their own. A 1960s Diplomat box around an Italian interwar safety pen says nothing about where the pen came from.