Magnetic disk apparatus and method of controlling the same

Abstract

A disk apparatus including: a head slider for being floated above a disk; a record/reproduction element provided at the head slider for recording and/or reproducing information on and/or from the disk; a displacer for shifting the record/reproduction element to approach closer to, or retreat farther away from, the disk; and a controller for controlling the displacer to shift the record/reproduction element in a direction to retreat rather from the disk, if the record/reproduction element has contacted the disk.

1 . A disk apparatus comprising: 
 a head slider for being floated above a disk;    a record/reproduction element provided at the head slider for recording and/or reproducing information on and/or from the disk;    a displacer for shifting the record/reproduction element to approach closer to, or retreat rather away from, the disk; and    a controller for controlling the displacer to shift the record/reproduction element in a direction to retreat farther from the disk, if the record/reproduction element has contacted the disk.    
   
   
       2 . The disk apparatus in  claim 1 , wherein the controller shifts the record/reproduction element in a direction of coming-closer to the disk until the record/reproduction element contacts the disk.  
   
   
       3 . The disk apparatus in  claim 1 , wherein the displacer is a piezoelectric actuator.  
   
   
       4 . The disk apparatus in  claim 3 , wherein the piezoelectric actuator detects the contact by monitoring a direct current voltage as applied to the piezoelectric actuator's electrode.  
   
   
       5 . The disk apparatus in  claim 1 , wherein the record/reproduction element is an MR element.  
   
   
       6 . The disk apparatus in  claim 5 , wherein the MR element detects the contact by utilizing a thermal asperity phenomenon.  
   
   
       7 . The disk apparatus in  claim 6 , comprising: 
 a circuit for handling a signal output from the MR element, subdivided into two parallel circuits, one of which is used for reading a signal with a frequency corresponding to inherent magnetic information, and the other of which is used for detecting a signal with its frequency corresponding to a thermal asperity.    
   
   
       8 . The disk apparatus in  claim 1 , comprising: 
 a strain gage to detect the contact by detecting a frictional force between the strain gage and the disk.    
   
   
       9 . The disk apparatus in  claim 1 , comprising: 
 a detector to detect the contact by acoustic emission methodology.    
   
   
       10 . A disk apparatus comprising: 
 a head slider for being floated above a disk;    a record/reproduction element provided at the head slider for recording and/or reproducing information on and/or from the disk;    a displacer for shifting the record/reproduction element to approach closer to, or retreat rather away from, the disk;    a detector for detecting acceleration; and    a controller to control the displacer to shift the record/reproduction element in a direction to retreat farther from, the disk, if the detector detects zero gravity or rapid acceleration.    
   
   
       11 . The disk apparatus in  claim 10 , wherein the displacer is designed to comprise a spring-mass system to operate as the detector.  
   
   
       12 . The disk apparatus in  claim 10 , wherein the displacer is a piezoelectric actuator.  
   
   
       13 . A control method of a disk apparatus, comprising: 
 shifting a record/reproduction element to approach closer to a disk;    detecting contact between the record/reproduction element and the disk;    shifting the record/reproduction element to retreat rather away from the disk;    storing a resultant shift amount in a memory.    
   
   
       14 . The control method in  claim 13 , comprising: 
 shifting the record/reproduction element to the resultant shift amount.    
   
   
       15 . The control method in  claim 1 , wherein the detecting includes a plurality of detecting at the different positions on the disk.  
   
   
       16 . The control method in  claim 15;  wherein 
 the different positions include the innermost periphery position, and the outermost periphery position.    
   
   
       17 . The control method in  claim 15 , comprising: 
 a proper shift amount at the position the record/ reproduction element locates according to the resultant of the plurality of detecting.