Disk drive apparatus

Abstract

A disk apparatus includes a disk having helically-formed tracks and storing information on said tracks; a motor for rotating said disk; a pick-up means having a focus servo means and a tracking servo means for reading information recorded on said disk by following the information stored on said tracks; traverse means having a stepping motor for moving said pick-up means by a specified distance; pulse generating means for generating pulse signals for controlling said stepping motor; stepping motor driving means for driving said stepping motor according to said pulse signals received from said pulse generating means; a step-out detecting means for detecting a step-out of said stepping motor; and a driving voltage changing means for changing a driving voltage of said stepping motor when said step-out detecting means detects the step-out in said stepping motor driving means.

We claim:  
     
         1 . A disk apparatus comprising: 
 a disk having helically-formed tracks and storing information on said tracks;    a motor for rotating said disk;    a pick-up means having a focus servo means and a tracking servo means for reading information recorded on said disk by following the information stored on said tracks;    traverse means having a stepping motor for moving said pick-up means by a specified distance;    pulse generating means for generating pulse signals for controlling said stepping motor;    stepping motor driving means for driving said stepping motor according to said pulse signals received from said pulse generating means;    a step-out detecting means for detecting a step-out of said stepping motor; and    a driving voltage changing means for changing a driving voltage of said stepping motor when said step-out detecting means detects the step-out in said stepping motor driving means.    
     
     
         2 . A disk apparatus in accordance with  claim 1  wherein said step-out detecting means comprises: 
 a track cross detecting means for detecting a number of tracks crossed by said pick-up; and  
 a pulse count detecting means for detecting a number of pulses from the output of said pulse generating means, wherein said step-out detecting means compares output values of said pulse count detecting means and said track cross detecting means and when the difference between the output values of the pulse count means and the tracking crossing detecting means exceeds a specified value, said step-out detecting means decides there to be a step-out of said stepping motor.  
 
     
     
         3 . A disk apparatus in accordance with  claim 1  wherein said step-out detecting means comprises a track cross speed detecting means for detecting a moving speed of said pick-up and a pulse rate detecting means for detecting a pulse rate (pulse frequency) output from said pulse generating means, wherein 
 said step-out detecting means compares output values of said pulse rate detecting means and said track cross speed detecting means and when the difference between the output values of the pulse rate detecting means and the track cross speed detecting means exceeds a specified value, said step-out detecting means determines it to be a step-out.  
 
     
     
         4 . A disk apparatus in accordance with  claim 1  wherein said step-out detecting means comprises: 
 a driving current detecting means for detecting a driving current of said stepping motor;  
 a pulse rate detecting means for detecting a pulse rate output from said pulse generating means; and  
 a reference current generating means for receiving a value detected by said pulse rate detecting means and outputting a reference value of a driving current when said stepping motor is rotated synchronously with the detected pulse rate, wherein said step-out detecting means, when the output value of said driving current detecting means exceeds the output value of said reference current creating means, decides it to be a step-out.  
 
     
     
         5 . A disk apparatus in accordance with  claim 1  wherein said step-out detecting means does not decide a period while said pick-up is moving from an inner periphery to an outer periphery of said disk following up tracks as a step-out.  
     
     
         6 . A disk apparatus in accordance with  claim 1  wherein said step-out detecting means comprises: 
 a pick-up position detecting means for detecting a position of said pick-up from information read via said pick-up; and  
 a target position storing means for storing a target position of said pick-up during a movement, wherein said step-out detecting means compares a value stored in said target position storing means with the value detected by said pick-up position detecting means after said pick-up moves, and said step-out detecting means, when the difference between those values exceeds a specified value, determines it as a step-out.  
 
     
     
         7 . A disk apparatus comprising: 
 a disk having helically-formed tracks and storing information on said tracks;    a motor for rotating said disk;    a pick-up means having a focus servo means and a tracking servo means for reading the information recorded on said disk by following the information stored on said tracks;    a traverse means having a stepping motor for moving said pick-up means by a specified distance;    a means of generating pulse signals for controlling said stepping motor;    a means of driving said stepping motor according to said pulse signals received from said pulse signal generating means;    a means of detecting step-up errors of said stepping motor; and    a means for changing the pulse rate output from said pulse generating means to a specified pulse rate when said step-out detecting means detects a step-out in said stepping motor driving means.    
     
     
         8 . A disk apparatus comprising: 
 a disk having helically-formed tracks and storing information on said tracks;    a motor for rotating said disk;    a pick-up means having a focus servo means and a tracking servo means for reading the information recorded on said disk by following the information stored on said tracks;    a traverse means having a stepping motor for moving said pick-up means by a specified distance;    a pulse generating means for generating pulse signals for controlling said stepping motor;    a stepping motor driving means of driving said stepping motor according to said pulse signals received;    a step-out detecting means for detecting a step-out of said stepping motor;    a step-out count storing means of storing the number of step-out times detected by said step-out detecting means;    a driving voltage changing means for changing a driving voltage of said stepping motor according to a value stored in said step-out count storing means, said driving voltage changing means being connected to said stepping motor driving means, and    pulse rate changing means for changing a frequency of pulses (pulse rate) output from said pulse generating means according to a value stored in said step-out count storing means.