The invention relates to a method for producing polymers, in particular synthetic nucleic acid double strands of optional sequence, comprising the steps:. A first adjusting member which adjusts the positions of magnetic poles of a first magnetic member disposed in the first developer bearing member is fixed to the developing apparatus. A first cable is connected from the target server to the first server and a second cable is connected from the target server to the second server. An apparatus for measuring a component of a rotating assembly comprises a light emitting micrometer configured to map the surface of a component and a range finder coupled to the micrometer for determining the location of the micrometer during measurement. In consequence, a device is controlled by electric potentials of the same polarity upon writing of data and upon erasing of data. The reference voltage generator converts the second current into a voltage and outputs the voltage as a reference voltage.