A fuel injector having a fuel heater and an insulating air jacket. Columnar crystal grains of MgB2 grow with the same tilted to the normal line of the substrate by supplying a magnesium flux and a boron flux from direction tilted each to the normal axis of a substrate in high vacuum. When a paper document printed by the document print data is collected after being distributed, the information medium controller transmits a collection completion update request including the child management ID read from the paper document by an exclusive reader.