A method for determining a working gap includes a first recording step for ejecting ink from a recording head onto a first recording medium to record a test pattern, a first imaging step for capturing the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, a function calculating step, a second recording step for recording the test pattern on a second recording medium, a second imaging step for capturing the test pattern recorded on the second recording medium, and a working gap determining step for determining, based on the number of pixels of the captured test pattern and a function, a distance between the recording head and the second recording medium.

An optical-information recording/reproducing apparatus of the present invention is capable of carrying out position detection of a reproduction image even if reproduction image data with incomplete alignment marks (markers) is obtained. A relative correlation value is calculated from a first correlation value retained by a first correlation-value retaining unit and a second correlation value retained by a second correlation-value retaining unit, and pass/fail of a position detection result of the marker is judged according to the relative correlation value. The pass/fail of the position detection result is judged by mutually comparing the detection positions of the markers judged as passes by the relative correlation-value judgement, the positions of the markers judged as fail by the relative correlation-value judgement or the mutual position judgement is complemented, and the position of two-dimensional data is detected based on the pass-judged markers and the complemented markers.

An optical-information recording/reproducing apparatus of the present invention is capable of carrying out position detection of a reproduction image even if reproduction image data with incomplete alignment marks (markers) is obtained. A relative correlation value is calculated from a first correlation value retained by a first correlation-value retaining unit and a second correlation value retained by a second correlation-value retaining unit, and pass/fail of a position detection result of the marker is judged according to the relative correlation value. The pass/fail of the position detection result is judged by mutually comparing the detection positions of the markers judged as passes by the relative correlation-value judgement, the positions of the markers judged as fail by the relative correlation-value judgement or the mutual position judgement is complemented, and the position of two-dimensional data is detected based on the pass-judged markers and the complemented markers.

This recording/reproducing apparatus that records or reproduces information by radiating light to a recording medium is provided with: a medium rotating unit that rotates the recording medium; a moving unit having a movable unit that is capable of moving within a predetermined plane; a rotation angle detecting unit that detects a rotating angle of the recording medium using an angle detection mark that is provided on the recording medium; a position detecting unit that detects a position of the recording medium using an eccentricity detection mark that is provided on the recording medium; and a member for fixing the rotation angle detecting unit and the position detecting unit. With respect to the member, the movable unit relatively moves within a plane substantially parallel to the recording surface of the recording medium, and the medium rotating unit is fixed to the movable unit.