Abstract: An optical receiving apparatus is provided which is constructed to compensate for a rise in offset level attributable to low-frequency response of a light-receiving device. An offset detecting circuit detects a quantity of electricity indicative of an offset current quantity which corresponds to the zero level of an optical signal within the current quantity output from the light-receiving device, and a current subtracting circuit reproduces the offset current quantity based on the detected quantity of electricity, subtracts the reproduced offset current quantity from the current quantity output from the light-receiving device, and supplies the result to a preamplifier.

Abstract: A head wire for use in a high-speed impact dot matrix printer head, having an elongated body, made of a high speed steel wire material or titanium alloy wire material. One end of the body is connectable to an armature of the printed head and a second end on an ink ribbon for printing characters on a paper material. The second end has a coating formed around its periphery and consists of a ceramic hard titanium compound or an aluminum oxide.