Apparatus for measuring the clearance of recording transducer, and a recorder using the apparatus, and a method of controlling the recorder

A recording transducer clearance measuring apparatus for measuring the clearance between a recording transducer and a recording medium which includes at least a conductive layer or conductive section, said apparatus comprising:

• a field electron emission electrode section disposed on the surface of said recording transducer confronting said recording medium and comprising at least one field electron emission electrode;
• a voltage source which applied a voltage, that is greater at least at a peak value thereof than the work function of the surface of said field electron emission electrode or the conductive layer or conductive section of said recording medium, between said field electron emission electrode section and the conductive layer or conductive section of said recording medium;
• a current measuring device, which is located on any current path among said voltage source, said field electron emission electrode section, and the conductive layer or conductive section of said recording medium, for measuring a current flowing on the current path;
• and
• a computation processor which receives a current value measured by said current measuring device and calculates the amount of clearance between said recording transducer and said recording medium;
• wherein said field electron emission electrode section is covered, in non-contact fashion on the side thereof confronting said recording medium, with a protection device made of a dielectric substance.

A recording transducer clearance measuring apparatus for measuring the clearance between a recording transducer and a recording medium which includes at least a conductive layer or conductive section, said apparatus comprising:

• a field electron emission electrode section disposed on the surface of said recording transducer confronting said recording medium and comprising at least one field electron emission electrode;
• a voltage source which applies a voltage, that is greater at least at a peak value thereof than the work function of the surface of said field electron emission electrode or the conductive layer or conductive section of said recording medium, between said field electron emission electrode section and the conductive layer or conductive section of said recording medium;
• a current measuring device, which is located on any current path among said voltage source, said field electron emission electrode section, and the conductive layer or conductive section of said recording medium, for measuring a current flowing on the current path;
• and
• a computation processor which receives a current value measured by said current measuring device and calculates the amount of clearance between said recording transducer and said recording medium;
• wherein said field electron emission electrode section comprises a plurality of field electron emission electrodes;
• and
• wherein said electrodes have work function which are different from each other.

A recording transducer clearance measuring apparatus for measuring the clearance between a recording transducer and a recording medium which includes at least a conductive layer or conductive section, said apparatus comprising:

• a field electron emission electrode section disposed on the surface of said recording transducer confronting said recording medium and comprising at least one field electron emission electrode;
• a voltage source which applies a voltage, that is greater at least at a peak value thereof than the work function of the surface of said field electron emission electrode or the conductive layer or conductive section of said recording medium, between said field electron emission electrode section and the conductive layer or conductive section of said recording medium;
• a current measuring device, which is located on any current path among said voltage source, said field electron emission electrode section, and the conductive layer or conductive section of said recording medium, for measuring a current flowing on the current path;
• and
• a computation processor which receives a current value measured by said current measuring device and calculates the amount of clearance between said recording transducer and said recording medium;
• wherein said field electron emission electrode section is fitted on the surface of said recording transducer confronting said recording medium by means of an advancement-retraction mechanism capable of adjusting the position of said field electron emission electrode section relative to said recording medium;
• wherein said recording transducer includes a recording element capable of writing and/or reading a record on said recording medium, said recording element being disposed on the surface of said recording transducer confronting said recording medium, and wherein said computation processor is designed to control said advancement/retraction mechanism so that said recording transducer has a specified clearance with respect to said recording medium;
• and
• wherein said advancement/retraction mechanism is divided into two advancement/retraction mechanisms for moving said field electron emission electrode section and said recording element independently, and wherein said computation processor is designed to control the movement of said two advancement/retraction mechanisms independently.

A recording transducer clearance measuring apparatus for measuring the clearance between a recording transducer and a recording medium which includes at least a conductive layer or conductive section, said apparatus comprising:

• a field electron emission electrode section disposed on the surface of said recording transducer confronting said recording medium and comprising at least one field electron emission electrode;
• a voltage source which applies a voltage, that is greater at least at a peak value thereof than the work function of the surface of said field electron emission electrode or the conductive layer or conductive section of said recording medium, between said field electron emission electrode section and the conductive layer or conductive section of said recording medium;
• and
• a current measuring device, which is located on any current path among said voltage source, said field electron emission electrode section, and the conductive layer or conductive section of said recording medium, for measuring a field electron emission current flowing on the current path;
• and
• wherein said field electron emission electrode section is fitted on the surface of said recording transducer confronting said recording medium by means of an advancement-retraction mechanisms capable of adjusting the position of said field electron emission electrode section relative to said recording medium;
• and
• wherein said recording transducer includes a recording element capable of writing and/or reading a record on said recording medium, said recording element being disposed on the surface of said recording transducer confronting said recording medium;
• said apparatus further comprising:
• an electrical converting-amplifying the field electron emission current measured by said current measuring device, and for controlling said advancement/retraction mechanism on the basis of the electrically converted and amplified field electron emission current so that said recording transducer has a specified clearance with respect to said recording medium;
• wherein the current measuring device measure only a field electron emission current flowing on the current path.

A method of controlling a recording apparatus comprising the steps of:

• generating an electric field, which is a function of the distance between a field electron emission electrode and a recording medium, on the surface of said field electron emission electrode confronting said recording medium;
• measuring a change in the quantity of electricity which is lost at said field electron emission electrode due to field electron emission that occurs between said field electron emission electrode and said recording medium;
• and
• controlling the clearance between a recording transducer and said recording medium in accordance with the change in the quantity of electricity which is lost at said field electron emission electrode section;
• wherein the measuring step includes measuring only a change in the quantity of electricity which is lost due to field electron emission by measuring only a field electron emission current.