Magnetic recording/reproducing apparatus and method for determining magnetic recording condition

A magnetic recording/reproducing apparatus, including:

• a recording head;
• a magnetoresistive reproducing head;
• a magnetic recording medium onto which information is recordable;
• and a heating unit heating a recording area of the magnetic recording medium, the apparatus having a configuration such that:
• information is recorded onto the magnetic recording medium by applying current to the recording head to generate a magnetic field while heating the recording area of the magnetic recording medium with the heating unit thereby to reduce coercivity of the magnetic recording medium;
• and information recorded onto the recording area of the magnetic recording medium is reproduced with the reproducing head, the magnetic recording/reproducing apparatus further comprising:
• a preliminary recording unit preliminarily recording information onto the recording area of the magnetic recording medium, by exerting control so that constant current or current with a constant amplitude waveform is applied to the recording head, while driving the heating unit in accordance with a preliminary drive condition so that heating power is provided by the heating unit to the recording area of the magnetic recording medium;
• a judgment unit judging which one of a reproduction signal evaluation value and a predetermined reference value is superior to the other, the reproduction signal evaluation value resulting from a reproduction signal obtained through reproduction, by the reproducing head, of information which has been preliminarily recorded by the preliminary recording unit onto the recording area;
• an extraction unit controlling the preliminary recording unit so that preliminary recording of information onto the recording area is conducted by the preliminary recording unit multiple times using a different preliminary drive condition each time, and for extracting, from a plurality of preliminary drive conditions respectively corresponding to preliminary recording conducted multiple times, a preliminary drive condition corresponding to a reproduction signal evaluation value which (i) has a judgment result by the judgment unit indicating that the reproduction signal evaluation value is in agreement with or superior to the reference value and (ii) is the best reproduction signal evaluation value among a plurality of reproduction signal evaluation values corresponding to the plurality of preliminary drive conditions;
• and
• a drive condition determining unit determining that the preliminary drive condition extracted by the extraction unit is a drive condition of the heating unit, which is used when information is recorded onto the magnetic recording medium, wherein:
• assuming that first preliminary recording is excluded from consideration, every time the preliminary recording unit conducts preliminary recording of information onto the recording area, the judgment unit judges which one of a reproduction signal evaluation value corresponding to preliminary recording currently conducted and the reference value is superior to the other;
• every time the judgment unit produces a judgment result indicating that a reproduction signal evaluation value is in agreement with or superior to the reference value, the extraction unit judges which one of reproduction signal evaluation values is superior to the other, between the reproduction signal evaluation value currently obtained and a previous reproduction signal evaluation value having an immediately preceding judgment result by the judgment unit indicating that the reproduction signal evaluation value is in agreement with or superior to the reference value;
• the extraction unit controls the preliminary recording unit so that heating power provided to the recording area is gradually increased with the number of times preliminary recording is conducted when preliminary recording of information onto the recording area is conducted by the preliminary recording unit multiple times;
• and
• when it is judged that the reproduction signal evaluation value currently obtained is inferior to the previous reproduction signal evaluation value as a result of judgment about superiority between the two reproduction signal evaluation values, the extraction unit extracts a preliminary drive condition corresponding to the previous reproduction signal evaluation value, from a plurality of preliminary drive conditions respectively corresponding to preliminary recording that has been conducted multiple times.