Base material processing apparatus and detection method

A base material processing apparatus comprising:

• a transport mechanism that transports a long band-like base material in a longitudinal direction along a predetermined transport path;
• an upstream detector that successively or intermittently detects a position of an edge of the base material in a width direction at an upstream detection position in the transport path to acquire an upstream detection result, wherein the upstream detection result includes data sections, each of the data sections being referred as an upstream data section;
• a downstream detector that successively or intermittently detects the position of the edge of the base material in the width direction at a downstream detection position located downstream of the upstream detection position in the transport path to acquire a downstream detection result, wherein the downstream detection result includes data sections, each of the data sections being referred as a downstream data section;
• and
• a displacement amount calculation part that, for each of the upstream data sections, identifies a highly matched downstream data section from among a plurality of downstream data sections, and calculates an amount of displacement of the base material in a transport direction or an amount of difference in a transport speed of the base material on the basis of an identification result,
• wherein the displacement amount calculation part uses a result of comparison between signals in a predetermined frequency band extracted from the upstream detection result and signals in the predetermined frequency band extracted from the downstream detection result to identify the highly matched downstream data section for each of the upstream data sections.