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_O_P_E_R_AT_I_O_NA_L_PR_I_N_CI_P_LE_O_F_F_LO_P_P_···.·y_·.····O..:....-.' . . . . . . . . . . . $Kw...··· • • .
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The floppy disk is designed to rotate the so-called
"diskette," a magnetic disk storage unit, to read out
and write in data at high speeds by bringing the
magnetic head in direct contact
witb a specifil!d
track
sector of 70 tracks formed in both surfaces of the
diskette.
1. Fundamental block diagram
Drive
select
Read circu it
Write circuit
Operation
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Write
In Icator
. /protect
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senso!",
IndeX~-'l'--
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sen_s~:JJJ'
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Head load-
Write protectr"··"
.
actuator
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,I
Head select
Read data
Write gate
Write data
Write protect
Motor ON
.
.
Head select
Head load
•
•
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~.Rea1/write~"""
•..".
Direction
•
Index
Motor ON
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Track 00
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Control circuit
1-_ _-,
Diskette
Head select
Motor
control circuit
2. Mechanism explanation
This device consists mainly of the following
mechanisms.
1)
Read/write head
The head is attached to the arm through a leaf
spring.
The head can follow the motion of
diskette easily.
Signals read out of the head are transmitted
through FPC (Flexible Printed Cable) to the read
amp. circuit.
2) Carriage assembly
2 units of read/write head are mounted on the
carriage. The carriage is located with the stepping
motor and lead screw.
3) Head locating mechanism
This is a high-precision, reliable head locating
mechanism using stepping motor and screw-driven
ball/V -groove system.
The stepping motor is of 7.5°/pulse, steel plate
type.
One pulse of step signal causes a 2-step rotation
by 15
0
,
thus pushing forward the head by one
track.
41 Diskette driving mechanism
A small-sized DC motor with tacho-generator is
employed. The motor rotation is transmitted
through the drive belt, spindle pulley and spindle
hub, thereby causing rotation of the diskette. This
spindle pulley is provided with a stroboscope to
check rotation interval.
5) Head load mechanism
This is a mechanism in which the head is brought
into contact with the diskette. It is operated by
the head load actuator.
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.
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