JPS5928861U - magnetic disk device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of drawings]

Fig. 1 is a block diagram of a microdisk device, Fig. 2 is a bottom view of its essential parts, Fig. 3 is a block diagram of a dirt detection device for a microdisc device to which the present invention is applied, and Fig. 4a shows how to prevent erroneous detection. FIG. 4 is a timing chart of the operation when there is no dirt, and FIG. 4 is a timing chart of the operation when there is dirt that may cause false detection. 5.10... Optical sensor, 11... Magnetic disk device, 12... Retriggerable one-shot circuit, 1
3...Pulse counter, 14...Alarm lamp circuit.

Claims (1)

[Scope of utility model registration request] A magnetic disk comprising: a detected object provided on a rotating shaft or a rotating body that moves together with the rotating shaft, leaving a rotational reference position of the disk; and a detector that detects the detected object and generates a rotational reference position signal. The apparatus includes a pulse generating circuit that generates a pulse having a cycle slightly shorter than the generation cycle of the rotational reference position signal or a wind pulse having a pulse width slightly shorter than the rotational reference position signal, and the detector It is composed of an optical sensor that detects an object to be detected and outputs a detection signal, and moreover, it detects dirt by counting the number of detection signals detected by the optical sensor while generating pulses or wind pulses from the pulse generation circuit. A magnetic disk device characterized by being provided with a counter for detection.