Disc recording and/or reproducing apparatus and disc presence detecting method

A disc recording and/or reproducing apparatus provided with disc exchange function to carry out recording/reproduction while carrying out exchange between plural discs held within a disc holding body includes a disc holding body within which plural discs are held at predetermined intervals (spacings) in a stacked state, a biasing member for biasing respective discs held within the disc holding body in a direction projected from the disc holding body, a recording/reproduction unit for carrying out recording and/or reproduction of information signals with respect to the optical disc drawn out, and a carrying mechanism for taking out a predetermined one disc from the disc holding body to carry it to the recording/reproduction unit. This carrying mechanism includes a drawing mechanism, and allows this drawing mechanism to move at least another one disc adjacent to a predetermined one disc held within the disc holding body toward the inside of the disc holding body against biasing force of the biasing member to draw out only the predetermined one disc in a direction projected from the disc holding body, and thus carry the predetermined one disc.

TECHNICAL FIELD 
This invention relates to a disc recording and/or reproducing apparatus 
provided with a disc exchange function to take out an arbitrary one disc 
from plural discs held (accommodated) within a disc holding body and to 
carry the disc thus taken out to a recording and/or reproduction unit to 
carry out recording and/or reproduction of information signals, and a 
detecting method for detecting presence of a disc accommodated within the 
disc holding body. 
BACKGROUND ART 
Hitherto, there have been used disc recording and/or reproducing 
apparatuses provided with disc exchange function adapted for accommodating 
in advance plural discs such as optical disc, magneto-optical disc or 
magnetic disc, etc. on which information signals are to be recorded, or 
have been recorded to selectively take out an arbitrary one disc from 
these plural discs to carry the disc thus taken out to a recording and/or 
reproduction unit to allow it to undergo loading with respect thereto and 
thereby carry out recording and/or reproduction of information signals. 
The disc recording/reproducing apparatus (hereinafter referred to as disc 
recording/reproduction unit as occasion may demand) of this kind comprises 
a disc accommodating body for accommodating plural discs therein, a 
drawing mechanism for selectively drawing out an arbitrary one disc from 
plural discs accommodated within the disc accommodating body, and a carry 
mechanism for carrying the disc drawn out by the drawing mechanism to the 
recording/reproduction unit. 
The disc accommodating body provided in this disc recording/reproduction 
unit is constituted so as to accommodate plural discs with a predetermined 
interval (spacing) therebetween in such a manner that their principal 
surfaces are opposite to each other. Namely, the plural discs are 
accommodated within the disc accommodating body in such a manner that they 
are stacked with to each other in upper and lower directions. 
In this case, in order to increase, without enlarging the disc 
recording/reproduction unit, the number of discs accommodated within this 
unit, it is required to improve accommodation efficiency of discs 
accommodated within the disc accommodating body. 
In order to improve the accommodation efficiency of discs into the disc 
accommodating body, the intervals (spacings) between the respective disc 
accommodating portions for accommodating discs one by one, which are 
constituted within the disc accommodating body, are reduced, thereby 
making it possible to realize such improvement. 
However, when the intervals between the disc accommodating portions are 
reduced, the intervals (spacings) between respective discs accommodated at 
the respective disc accommodating portions are reduced. For this reason, 
it would become impossible to draw out, by using the disc drawing 
mechanism, only a predetermined one disc from plural discs accommodated at 
the disc accommodating portions in such a manner that they are stacked. 
Particularly, in the unit using a disc drawing mechanism adapted to grip or 
grasp a predetermined one disc from plural discs from a direction 
perpendicular to the principal surface and to draw the disc out, it 
becomes impossible to insert the gripping or grasping portion for gripping 
or grasping the disc into portions between discs stacked to each other. As 
a result, it becomes impossible to carry out drawing operation of the 
disc. In the disc drawing mechanism for gripping or grasping the disc from 
a direction perpendicular to the principal surface and for taking-out of 
the disc, it is necessary to open and close the gripping or grasping 
portion for the purpose of gripping or grasping the disc. In order to 
securely carry out drawing operation of a predetermined disc, gaps into 
which the gripping or grasping portion is inserted aloowing it to open and 
close it are required between respective discs accommodated in such a 
manner that they are stacked to each other. As a result, it has become 
impossible to realize improvement in the accommodation efficiency of discs 
accommodated within the disc accommodating body. 
In addition, when a portion of the disc drawing mechanism comes into 
contact with the signal recording surface of the disc in carrying out 
drawing operation of the disc, there is also the possibility that this 
signal recording surface may be damaged. 
DISCLOSURE OF THE INVENTION 
With the above in view, an object of this invention is to provide a disc 
recording and/or reproducing apparatus adapted to prevent enlargement of 
the apparatus itself so that improvement in the accommodation efficiency 
of discs can be realized. 
Another object of this invention is to provide a disc recording and/or 
reproducing apparatus capable of securely taking out only a predetermined 
one disc from the disc holding body which holds plural discs therewithin. 
A further object of this invention is to provide a disc recording and/or 
reproducing apparatus capable of realizing protection of discs held within 
the disc holding body and discs caused to undergo drawing operation from 
the disc holding body. 
A still further object of this invention is to provide a disc recording 
and/or reproducing apparatus and a disc presence detecting method, which 
are capable of quickly or readily carrying out detection of presence of 
discs in a plurality of disc accommodating portions. 
A further object of this invention is to provide a disc recording and/or 
reproducing apparatus and a disc presence detecting method in which the 
state of the plural disc accommodating portions is stored in advance to 
quickly or readily carry out drawing operation of the discs, and thus to 
have ability of quickly or readily recording and/or reproducing 
information signals with respect to plural discs. 
A disc recording and/or reproducing apparatus according to this invention 
proposed for the purpose of realizing objects as described above 
comprises: a disc holding body within which plural discs are held in such 
a manner that their principal surfaces are opposite to each other and 
those discs are spaced with a predetermined interval (spacing) 
therebetween; a biasing member for biasing the respective discs held 
within the disc holding body in a direction projected from the disc 
holding body; a recording and/or reproduction unit for carrying out 
recording and/or reproduction of information signals with respect to the 
disc; and a carrying mechanism for taking out a predetermined one disc 
from the disc holding body to carry it to the recording and/or 
reproduction unit. This carrying mechanism includes a drawing mechanism 
for moving at least the other one disc adjacent to a predetermined one 
disc held within the disc holding body toward the inside of the disc 
holding body against biasing force of the biasing member to draw out the 
predetermined one disc in a direction projected from the disc holding body 
so as to grip or grasp it. In addition, the carrying mechanism carries a 
predetermined one disc to the recording and/or reproduction unit in the 
state where it is held by the drawing mechanism. 
The drawing mechanism used in this case comprises a pressing operation 
portion for moving at least the other one disc adjacent to a predetermined 
one disc toward the inside of the holding body against biasing force of 
the biasing member, and a grip mechanism for gripping or grasping the 
predetermined one disc from a direction perpendicular to the principal 
surface of the disc in the state where at least the other one disc 
adjacent to the predetermined one disc is moved toward the inside of the 
holding body against biasing force of the biasing member by the pressing 
operation portion. This grip mechanism comprises a pair of grip arms and a 
switching portion for carrying out switching between a first state where 
these pair of grip arms grip or grasp the disc and a second state where 
the grip arms release the disc. 
The disc recording and/or reproducing apparatus according to this invention 
further comprises a transfer mechanism moving between a position within 
the apparatus and a position outside the apparatus to transfer the disc, 
thus to allow the disc holding body to hold further discs by the transfer 
mechanism, or to take out the disc held within the disc holding body 
toward the outside of the disc holding body by the transfer mechanism. 
Moreover, a disc recording and/or reproducing apparatus according to this 
invention comprises: a disc holding body within which plural discs are 
held in such a manner that their principal surfaces are opposite to each 
other and those discs are spaced with a predetermined interval (spacing) 
therebetween; a recording and/or reproduction unit for carrying out 
recording and/or reproduction of information signals with respect to the 
disc; and a carrying mechanism for taking out a predetermined one disc 
from the disc holding body to carry it to the recording and/or 
reproduction unit. This carrying mechanism includes a drawing mechanism 
for moving at least the other one disc adjacent to a predetermined one 
disc held within the disc holding body toward the inside of the disc 
holding body so as to draw out the predetermined one disc in a direction 
projected from the disc holding body to grip or grasp it. In addition, the 
carrying mechanism carries the predetermined one disc to the recording 
and/or reproduction unit in the state where it is held by the drawing 
mechanism. 
Further, a disc recording and/or reproducing apparatus according to this 
invention comprises: a disc holding body within which plural discs are 
held in such a manner that their principal surfaces are opposite to each 
other and those discs are spaced with a predetermined interval (spacing) 
therebetween; a recording and/or reproduction unit for carrying out 
recording and/or reproduction of information signals with respect to the 
disc; a carrying mechanism for taking out a predetermined one disc from 
the disc holding body to carry it to the recording and/or reproduction 
unit; and a detection mechanism provided at the carrying mechanism and 
adapted for detecting presence of the disc within the disc holding body. 
In this case, the disc carrying mechanism includes a drawing mechanism for 
moving at least the other one disc adjacent to a predetermined one disc 
held within the disc holding body toward the inside of the disc holding 
body to draw out the predetermined one disc in a direction projected from 
the disc holding body, and thus to carry the predetermined one disc to the 
recording and/or reproduction unit in the state where it is held by the 
drawing mechanism. 
Furthermore, a disc presence detecting method according to this invention 
comprises: the steps of moving, to a position where a disc is accommodated 
at a disc accommodating portion of a disc holding body, a drawing 
mechanism for moving, toward the inside of the disc holding body, at least 
the other one disc adjacent to a predetermined one disc held within the 
disc holding body in which plural disc accommodating portions adapted for 
accommodating plural discs in such a manner that their principal surfaces 
are opposite to each other and those discs are spaced with a predetermined 
interval (spacing) therebetween, and for drawing out the predetermined one 
disc in a direction projected from the disc accommodating portion of the 
disc holding body for holding the disc; thereafter detecting, by a 
detecting mechanism provided at the drawing mechanism and adapted for 
detecting presence of the disc within the disc holding body, whether or 
not the disc is accommodated at the disc accommodating portion of the disc 
holding body; and thereafter moving the drawing mechanism to any other 
disc accommodating portion adjacent to the disc accommodating portion in 
which detection as to whether or not the disc was accommodated has been 
made, so as to carry out, by the detecting mechanism, a detecting 
operation as to whether or not the disc is accommodated at the other disc 
accommodating portion and to repeatedly carry out such detecting operation 
for the other disc accommodating portions. 
In addition, the result detected by the detecting mechanism is stored into 
the memory section in correspondence with each disc accommodating portion 
of the disc holding body. 
Still further objects of this invention and more practical advantages or 
merits obtained by this invention will become more apparent from the 
description of the embodiments of which explanation will be given below.

BEST MODE FOR CARRYING OUT THE INVENTION 
Explanation will be given by taking the example where this invention is 
applied to a disc recording/reproducing apparatus using an optical disc as 
a recording medium. 
The disc recording/reproducing apparatus (hereinafter referred to as disc 
recording/reproduction unit as occasion may demand) comprises an outer 
casing 1 constituting the unit body as shown in FIG. 1, and a disc 
accommodating body 2 constituting disc holding means for accommodating and 
holding plural optical discs 101, as shown in FIG. 2, is disposed within 
the outer casing 1. 
The optical disc 101 used as the recording medium for this disc 
recording/reproduction unit is such that a signal recording layer is 
formed on a disc base (substrate) having rigidity formed by molding 
synthetic resin having light transmissivity such as polycarbonate resin. 
Since this optical disc 101 is formed by using a disc base having high 
rigidity as described above, it has a strength such that even if pressing 
operation is implemented from the direction perpendicular to the principal 
surface, it is not deformed. Moreover, as shown in FIG. 2, at the central 
portion of the optical disc 101, there is bored a center hole 102 engaged 
with a centering member provided at a disc table constituting the disc 
rotational drive mechanism when loaded with respect to the disc rotational 
drive mechanism of the recording/reproduction unit to carry out centering 
with respect to the disc table. 
The disc accommodating body 2 for accommodating and holding plural optical 
discs 101 is provided in the state positioned substantially at the central 
portion in upper and lower directions of the front wall 1a side of the 
outer casing 1, as shown in FIG. 1. This disc accommodating body 2 is of a 
structure capable of holding plural optical discs 101 in such a manner 
that their principal surfaces are opposite to each other and those discs 
are spaced with a predetermined interval (spacing) therebetween. As shown 
in FIG. 2, the disc accommodating body 2 is formed so as to have a size 
(dimensions) such that it can accommodate and hold the optical discs 101 
in a horizontal state, wherein plural supporting projected pieces 19 for 
supporting the outer circumferential edges of the optical discs 101 are 
provided in a projected manner (hereinafter simply referred to as 
projected as occasion may demand) in the state opposite to each other at 
the inside surfaces of both side walls 2a, 2b that are positioned opposite 
to each other. As shown in FIG. 3, these supporting projected pieces 19 
are formed at equal intervals (distances) in a multi-step form in a height 
direction of the side walls 2a, 2b of the disc accommodating body 2, and 
disc supporting portions 18 are constituted by respective pairs of 
supporting projected pieces 19 projected at the same height on the left 
and right side walls 2a, 2b, resepctively. 
Further, the supporting projected pieces 19 formed in the multi-step form 
in the height direction of the disc accommodating body 2 are adapted so 
that when the disc accommodating body 2 is assumed to be constituted as an 
accommodating body for accommodating optical disc 101 having thickness d 
caused to be 1.2 mm, the supporting projected pieces 19 are formed at 
pitch P of about 2.5 mm. 
Further, as shown in FIGS. 1 and 3, the disc recording/reproduction unit 
according to this invention comprises a disc carrying mechanism 70 
provided with a disc drawing mechanism 23 for drawing out and carrying the 
optical disc 101 accommodated and held within the disc accommodating body 
2 in a manner opposite to the opened front side of the disc accommodating 
body 2. 
Further, the disc recording/reproduction unit is adapted so that first and 
second recording/reproduction units 5, 6 for carrying out recording and/or 
reproduction of information signals with respect to the optical disc 101 
drawn out from the disc accommodating body 2 and carried by the disc 
carrying mechanism 70 are disposed in a manner positioned at the lower 
side of the disc accommodating body 2. As shown in FIG. 1, these first and 
second recording/reproduction units 5, 6 are disposed at the lower step 
side of the disc accommodating body 2 in such a manner that they are 
stacked to each other. Since the first and second recording/reproduction 
units 5, 6 serve to carry out recording and/or reproduction of information 
signals with respect to the optical disc 101 carried by the disc carrying 
mechanism 70, they each comprise a disc rotational drive mechanism for 
rotationally operating the optical disc 101 carried by the disc carrying 
mechanism 70, and mechanisms required for carrying out recording and/or 
reproduction of information signals such as optical pick-up device or 
magnetic head device, etc. for carrying out recording and/or reproduction 
of information signals with respect to the optical disc 101 rotationally 
operated by the disc rotational drive mechanism. 
Furthermore, at the upper side of the disc accommodating body 2, there is 
provided a disc exchange mechanism 3 for carrying out exchange between 
optical discs 101 accommodated within the disc accommodating body 2. This 
disc exchange mechanism 3 comprises a disc tray 4 adapted so that optical 
disc 101 drawn out and carried from the disc accommodating body 2 by the 
disc carrying mechanism 70 is mounted, or optical disc 101 to be 
accommodated within the disc accommodating body 2 is mounted. In this disc 
tray 4, movement operation in the direction indicated by arrow A.sub.1 or 
in the direction indicated by arrow A.sub.2 in FIGS. 1 and 4 is carried 
out extending over inside and outside of the outer casing 1 of the disc 
tray 4 as shown in FIG. 4 within the range between a first position where 
it is accommodated within the outer casing 1 shown in FIG. 1 and a second 
position where it is projected toward the outside of the outer casing 1 
shown in FIG. 4 through an insertion/withdrawal hole 16 provided at the 
front wall la of the outer casing 1 and is carried out by the tray 
movement operation mechanism provided with drive motor (not shown). 
Namely, when the tray movement operation mechanism is driven, the disc 
tray 4 is caused to undergo movement operation in the direction indicated 
by arrow A.sub.1 or in the direction indicated by arrow A.sub.2 in FIGS. 1 
and 4 while being guided by a fixed guide rail 17a and a movement guide 
rail 17b caused to undergo relative movement with respect to the fixed 
guide rail 17a. 
The disc exchange mechanism 3 is adapted so that in the state where the 
optical disc 101 is drawn out and carried from the disc accommodating body 
2 by the disc carrying mechanism 70 and is mounted on the disc tray 4, it 
moves the disc tray 4 in the direction indicated by arrow A.sub.1 in FIGS. 
1 and 4 to the second position projected toward the outside of the outer 
casing 1, and there results the state where the optical disc 101 mounted 
on the disc tray 4 can be exchanged. When a new optical disc 101 is 
mounted on the disc tray 4 moved to the second position to draw the disc 
tray 4 into the outer casing 1 to move it to the first position, the disc 
carrying mechanism 70 draws out, from on the disc tray 4, the optical disc 
101 mounted on the disc tray 4 to carry it and insert it into a 
predetermined disc supporting portion 18 of the disc accommodating body 2 
to allow the disc supporting portion to hold the disc. By such an 
operation, exchange of the optical disc 101 accommodated and held within 
the disc accommodating body 2 is carried out through the disc exchange 
mechanism 3. 
Meanwhile, at the disc accommodating body 2, as shown in FIG. 2, there are 
provided disc pressing springs 20 for biasing the optical discs 101 
supported by the respective disc supporting portions 18 in a direction 
projected from the disc accommodating body 2. These disc pressing springs 
20 are provided in the state positioned at the back side opposite to the 
opened opening portion 2c side where insertion/withdrawal of the optical 
disc 101 is carried out with respect to the disc accommodating body 2. 
Each disc pressing spring 20 is formed by leaf spring, and is attached in 
the state where the base end portion 20a side is fixed to the outside 
surface side of a peripheral wall 18a surrounding the disc supporting 
portion 18 positioned at the back face wall 2d side of the disc 
accommodating body 2, and a curved projected portion 20b at front end side 
thereof is projected into the disc accommodating body 2 through a cut hole 
18b provided substantially at the central portion of the peripheral wall 
18a. Accordingly, the optical disc 101 is accommodated within the disc 
accommodating body 2 in such a manner that the insertion end of the 
optical adisc 101 into the disc accommodating body 2 is caused to be in 
contact with the disc pressing spring 20. Moreover, the optical disc 101 
accommodated within the disc accommodating body 2 is pushed or pressed in 
the direction indicated by arrow B.sub.1 in FIG. 2 which is the direction 
of insertion into the disc accommodating body 2, whereby it is further 
moved toward the inside of the disc accommodating body 2 in such a manner 
that the disc pressing spring 20 is caused to undergo elastic displacement 
as indicated by broken lines in FIG. 2. When the pressing (pushing) 
operation is released, the optical disc 101 experiences biasing force of 
the disc pressing spring 20 which has been caused to undergo pressing 
displacement. Thus, this optical disc 101 is pressed in the direction 
indicated by arrow B.sub.2 in FIG. 2 which is the direction projected away 
from the disc accommodating body 2 which is toward the opening portion 2c 
side of the disc accommodating body 2. 
The disc supporting springs 20 for pressing and supporting the optical 
discs 101 accommodated within the disc accommodating body 2 are provided 
at respective disc supporting portions 18 in a manner respectively 
corresponding thereto so as to have ability of respectively independently 
pressing the optical discs 101 supported by the disc supporting portions 
18. 
Moreover, at the side wall 2b side perpendicular to a back face wall 2d of 
the disc accommodating body 2, as shown in FIG. 2, there is provided a 
disc supporting spring 21 for preventing the optical disc 101 accommodated 
within the disc accommodating body 2 from inadvertently slipping off from 
the opening portion 2c side. This disc supporting spring 21 is also formed 
by leaf spring, and is attached in the state where the base end portion 
21a is fixed to the outside surface of the peripheral wall 18a positioned 
at the side wall 2b side of the disc accommodating body 2, and a curved 
projected portion 21b at the front end side thereof is projected into the 
disc accommodating body 2 through a cut portion 18c provided at the 
peripheral wall 18a. 
Further, the optical disc 101 is adapted so that when it is accommodated 
within the disc accommodating body 2, the outer circumferential edge 
positioned at the opening portion 2c side of the disc accommodating body 2 
from the center hole 102 is pressed and supported by the projected portion 
21b at the front end side of the disc supporting spring 21. At this time, 
the disc pressing spring 21 is placed in the state where it is slightly 
pressed by the optical disc 101. Accordingly, the optical disc 101 is 
accommodated and held within the disc accommodating body 2 in the state 
where it is pressed and biased in the direction indicated by arrow B.sub.1 
in FIG. 2 toward the inside of the disc accommodating body 2 by the disc 
supporting spring 21, and is pressed and biased in the direction indicated 
by arrow B.sub.2 in FIG. 2 which is the direction projected away from the 
disc accommodating body 2 which is the direction opposite to the above by 
the disc pressing spring 20. Thus, the optical disc 101 is held in a 
stable state at a fixed position within the disc accommodating body 2 so 
that inadvertent slipping off from the disc accommodating body 2 is 
prevented. 
While the disc supporting spring 21 is disposed only at the side wall 2b 
side of the disc accommodating body 2 in the above-described example, it 
may be disposed also at the other side wall 2a side as shown in FIG. 5. 
A disc supporting spring 22 disposed at the other side wall 2a side is also 
formed by leaf spring, and is attached in the state where the base end 
portion 22a is fixed at the outside surface of the peripheral wall 18a 
positioned at the side wall 2a of the disc accommodating body 2, and a 
curved projected portion 22b at the front end side thereof is projected 
into the disc accommodating body 2 through a cut hole 2g provided at the 
side wall 2a. Further, this disc supporting spring 22 is also attached on 
the outside surface of the peripheral wall 18a positioned at the side wall 
2a of the disc accommodating body 2 in such a manner that the projected 
portion 22b of the front end portion side supports the outer 
circumferential edge positioned at the opening portion 2c side of the disc 
accommodating body 2 from the center hole 102 of the optical disc 101 
accommodated within the disc accommodating body 2. 
By respectively providing the disc supporting springs 21, 22 at the both 
side walls 2a, 2b opposite to each other of the disc accommodating body 2, 
the optical disc 101 accommodated within the disc accommodating body 2 is 
pressed and biased in the direction indicated by arrow C.sub.1 and in the 
direction indicated by arrow C.sub.2 in FIG. 5 toward the inside of the 
disc accommodating body 2 in the state pressed and supported by the disc 
supporting springs 21, 22 from the both sides. 
It is to be noted that the interval (spacing) L.sub.1 between the 
respective projections 21b, 22b of the pair of disc supporting springs 21, 
22, respectively, is caused to be a value narrower than the diameter 
R.sub.1 of the optical disc 101. Accordingly, when the optical disc 101 is 
accommodated into the disc accommodating unit 2, the respective disc 
supporting springs 21, 22 are pressed by the optical disc 101 and are 
caused to undergo elastic displacement in a direction opposite to the 
direction indicated by arrow C.sub.1 and in a direction opposite to the 
direction indicated by arrow C.sub.2 in FIG. 5. 
Also in the example shown in FIG. 5, the optical disc 101 to be 
accommodated into the disc accommodating body 2 is accommodated and held 
within the disc accommodating body 2 in the state where it is pressed and 
biased toward the inside of the disc accommodating body 2 by the 
respective disc supporting springs 21, 22, and is pressed and biased in a 
direction projected away from the disc accommodating body 2 which is the 
opposite direction to that caused by the respective disc supporting 
springs 21, 22 by the disc pressing spring 20. Thus, the optical disc 101 
is held in the stable state at a fixed position within the disc 
accommodating body 2. As a result, inadvertent slipping off from the disc 
accommodating body 2 is prevented. 
While the disc pressing spring 20 and the disc supporting springs 21, 22 
are attached through the disc accommodating body 2 in the above-described 
embodiment, they may be disposed at the outer casing 1 side. 
Further, the disc carrying mechanism 70 adapted for selectively drawing out 
optical disc 101 accommodated within the disc accommodating body 2 so as 
to carry it to the first or second recording/reproduction units 5, 6, or 
for drawing out optical disc 101 loaded with respect to the first or 
second recording/reproduction units 5, 6 so as to carry it to a 
predetermined disc supporting portion 18 of the disc accommodating body 2 
is disposed in a manner opposite to the opened front side of the disc 
accommodating body 2. 
This disc carrying mechanism 70 comprises, as shown in FIG. 1, a disc 
carrying body 7 that is caused to undergo vertical movement operation in 
upper and lower directions extending across the disc exchange mechanism 3 
disposed at the upper side of the disc accommodating body 2 and the second 
recording/reproduction unit 6 disposed at the lowermost side of the disc 
accommodating body 2, i.e., in the direction indicated by arrow D.sub.1 
and in the direction indicated by arrow D.sub.2 in FIG. 1. This disc 
carrying body 7 is supported by a pair of supporting shafts 10, 11 
disposed in parallel to the height direction perpendicular to the 
principal surface of the optical disc 101 accommodated within the disc 
accommodating body 2. The disc carrying body 7 is disposed in a manner 
opposite to the opening portion 2c of the disc accommodating body 2 so 
that it can be moved in vertical movement direct ion (in upper and lower 
directions) of the direction indicated by arrow D.sub.1 and the direction 
indicated by arrow D.sub.2 in FIG. 1. The support shafts 10, 11 for 
supporting the disc carrying body 7 are supported between a first 
supporting base 12 disposed at the upper side within the outer casing 1 
and a second supporting base 13 disposed at the lower side within the 
outer casing 1. 
The disc carrying body 7 is caused to undergo vertical movement operation, 
by a vertical movement operation mechanism 71, extending across the disc 
exchange mechanism 3 of the upper side and the second 
recording/reproduction unit 6 of the lowermost side while being guided by 
the first and second support shafts 10, 11. This vertical movement 
operation mechanism 71 comprises a timing belt 9 in an endless form in 
which the middle portion is fixed to the disc carrying body 7 through a 
fixing member (appliance) 8, and a pair of first and second feed gears 14, 
15 on which the timing belt 9 is wound. The first feed gear 14 is 
rotatably attached on the first supporting base 12, and the second feed 
gear 15 is rotatably attached on the second supporting base 13. Further, 
the second feed gear 15 positioned at the lower side is connected to, 
e.g., drive motor disposed at the second supporting base 13 side although 
not shown. When the drive motor is driven and the second feed gear 15 is 
rotationally operated so that the timing belt 9 turns around the first and 
second feed gears 14, 15, the disc carrying body 7 is caused to undergo 
movement operation in the vertical direction indicated by arrow D.sub.1 
and the direction indicated by arrow D.sub.2 in FIG. 1. 
Moreover, at the surface side opposite to the disc carrying body 7 of the 
first supporting base 12, there is provided an upper (upward) position 
detecting switch 72 for detecting that it is caused to undergo pressing 
operation by the disc carrying body 7 when the disc carrying body 7 has 
been moved to the upper (upward) position. Further, at the surface side 
opposite to the disc carrying body 7 of the second supporting base 13, 
there is provided a lower (downward) position detecting switch 73 for 
detecting that is caused to undergo pressing operation by the disc 
carrying body 7 when the disc carrying body 7 has been moved to the lower 
(downward) position. 
Further, at the disc carrying body 7, as shown in FIG. 2, there is provided 
a disc drawing mechanism 23 for carrying out delivery/receipt (transfer) 
of the optical disc 101 between the disc carrying body 7 and the disc 
accommodating body 2, between the disc carrying body 7 and the disc 
exchange mechanism 3, and between the disc carrying body 7 and the first 
and second recording/reproduction units 5, 6. This disc drawing mechanism 
23 is moved in the direction indicated by arrow E.sub.1 and in the 
direction indicated by arrow E.sub.2 in FIG. 2 which are the directions in 
parallel to the principal surface of the optical disc 101 accommodated 
within the disc accommodating body 2 to thereby grip or grasp the optical 
disc 101 accommodated within the disc accommodating body 2 so as to draw 
it out, and to accommodate the optical disc 101 thus drawn out into the 
disc accommodating unit 2. 
The disc drawing mechanism 23 is adapted so that when it is located at the 
position opposite to the disc accommodating body 2, it carries out 
delivery/receipt (transfer) of the optical disc 101 between the disc 
accommodating body 2 and the disc carrying body 7. When the disc drawing 
mechanism 23 is located at the position opposite to the disc exchange 
mechanism 3, it carries out delivery/receipt (transfer) of the optical 
disc 101 between the disc exchange mechanism 3 and the disc carrying body 
7, and when it is located at the position opposite to the first or second 
recording/reproduction unit 5, 6, it carries out delivery/receipt 
(transfer) of the optical disc 101 between the first or second 
recording/reproduction unit 5, 6 and the disc carrying body 7. 
Further, the disc drawing mechanism 23 disposed on the disc carrying body 7 
comprises, as shown in FIGS. 6 and 7, a disc grip mechanism 74 for 
gripping or grasping the optical disc 101, a grip mechanism supporting 
member 31 to which the grip mechanism 74 is attached, and a movement 
member 39 adapted and the grip mechanism supporting member 31 is supported 
so that it can be relatively moved. 
As shown in FIG. 6, the movement member 39 by which the grip mechanism 
supporting member 31 is supported is formed in a rising manner 
(hereinafter simply referred to as rising-formed as occasion may demand) 
and in such a manner that side plates 39b, 39c are opposite to each other 
on the both sides of a bottom plate 39a, and is formed so as to take 
substantially channel shape. At the side of the outside surface of one 
side plate 39b, as shown in FIG. 8, there is projected toward the outside, 
a belt connection portion 47 to which the middle portion of a timing belt 
56, in an endless form constituting movement operation mechanism 75 for 
allowing the movement member 39 to undergo movement operation, is 
connected. On the lower surface of the bottom plate 39a of the movement 
member 39, as shown in FIGS. 6 and 9, a movement guide shaft 51 is 
attached in a manner in which the movement guide shaft 51 hangs down. The 
movement member 39 is disposed on the disc carrying body 7 in the state 
where the movement guide shaft 51 is inserted through a movement guide 
groove 61 bored through the disc carrying body 7. 
Meanwhile, as shown in FIG. 2, the movement guide groove 61 through which 
the movement guide shaft 51 is inserted is bored extending over 
substantially the entire length of the disc carrying body 7 in parallel to 
the direction in which the optical disc 101 is caused to undergo 
insertion/withdrawal with respect to the disc accommodating body 2. 
Further, the movement member 39 is disposed on the disc carrying body 7 in 
the state where the movement guide shaft 51 is inserted through the 
movement guide groove 61, and is moved in the direction indicated by arrow 
E.sub.1 or in the direction indicated by arrow E.sub.2 in FIG. 2 while 
being guided by the movement guide groove 61. 
Moreover, at the other side plate 39c of the movement member 39, as shown 
in FIGS. 6, 7 and 9, there is bored a cam groove 40 adapted so that the 
grip mechanism supporting member 31 disposed on the movement member 39 is 
relatively moved with respect to the movement member 39, whereby the cam 
groove 40 allows the disc grip mechanism 74 to undergo opening/closing 
operation. This cam groove 40 is composed of a broad horizontal groove 
portion 40a, and first and second inclined groove portions 41, 42, 
respectively, inclined in a manner branched from the horizontal groove 
portion 40a and spaced away from each other. Further, at the upper end 
side of the other side plate 39c, as described later, there is attached an 
engagement lever 45 that is engaged with an engagement recessed portion 37 
provided at the grip mechanism supporting member 31, and adapted for 
limiting relative movement with respect to the movement member 39 of the 
grip mechanism supporting member 31. This engagement lever 45 is rotatably 
attached in the direction indicated by arrow F.sub.1 and in the direction 
indicated by arrow F.sub.2 in FIGS. 6 and 9. The directions indicated by 
arrows F.sub.1 and F.sub.2 are the directions perpendicular to the 
movement direction of the movement member 39 with the support shaft 43 
acting as the center in the state where the base end portion side is 
pivotally supported on a support shaft 43 projected on the side of the 
outside surface of the other side plate 39c. At the front end side of the 
engagement lever 45, there is attached an engagement pin 44 in a 
cylindrical form which is engaged with the engagement recessed portion 37. 
This engagement pin 44 is attached in a manner perpendicular to the 
rotational direction of the engagement lever 45. In addition, the 
engagement lever 45 is rotationally biased in the direction indicated by 
arrow F.sub.1 in FIGS. 6 and 9 by a torsion coil spring 46 attached in 
such a manner that one arm portion is held by the other side plate 39c and 
the other arm portion is held by the engagement pin 44. 
Further, as shown in FIGS. 6, 10 and 11, the grip mechanism supporting 
member 31 supported on the movement member 39 is formed so as to take a 
channel shape in cross section in the state where side plates 31b, 31c are 
extending upwards and formed in a manner opposite to each other on the 
both sides of a bottom plate 31a similarly to the side plates 39b, 39c of 
movement member 39. As shown in FIGS. 6 and 7, this grip mechanism 
supporting member 31 is disposed on the bottom plate 39a of the movement 
member 39 in such a manner that it is fitted between the side plates 39b, 
39c of the movement member 39. At the lower surface side of the bottom 
plate 39a of the grip mechanism supporting member 39, there is attached, 
in a manner hanging down, an operation shaft 35 inserted into an elongated 
hole 52 bored through the bottom plate 39a of the movement member 39 and 
the movement guide groove 61 bored through the disc carrying body 7. The 
grip mechanism supporting member 31 disposed on the movement member 39 in 
the state where the operation shaft 35 is inserted into the elongated hole 
52 is relatively moved with respect to the movement member 39 within the 
range of the elongated hole 52. 
Between the grip mechanism supporting member 31 supported on the movement 
member 39 and the movement member 39, an extension (tensile) spring 76 is 
stretched. As shown in FIGS. 6 and 7, this extension spring 76 is 
stretched between a spring holding piece 77 formed in a manner in which 
the spring holding piece 77 is turned back toward the internal side at one 
end of the upper edge side of one side plate 39b of the movement member 39 
and a spring holding piece 78 formed in a manner in which the spring 
holding piece 78 is turned back toward the outside at the other end of the 
upper edge side of one side plate 31b of the grip mechanism supporting 
member 31. As the result of the fact that the extension spring 76 is 
stretched in this way, the grip mechanism supporting member 31 is 
supported by the movement member 39 in the state causing the grip holding 
supporting member 31 to undergo biasing so that it can be moved in the 
direction indicated by arrow G.sub.1 in FIG. 6 which is the direction 
projected from the movement member 39. 
Further, at the front end sides of the side plates 31b, 31c of the grip 
mechanism supporting member 31, i.e., in a manner positioned substantially 
at the central portion of the front end side opposite to the disc 
accommodating body 2 when the grip mechanism supporting member 31 is 
disposed on the disc carrying body 7 as shown in FIG. 2, there is formed 
as shown in FIGS. 6 and 11 an engagement recessed portion 48 with which 
the outer circumferential portion of a predetermined one optical disc 101 
accommodated within the disc accommodating body 2 is engaged. This 
engagement recessed portion 48 is formed so that its width gradually 
becomes broader from the internal side toward the opening end side, and is 
formed in such a manner that the internal end side thereof has a width 
W.sub.1 substantially equal to the thickness d of the optical disc 101. 
Moreover, at upper and lower portions of the engagement recessed portion 
48 of the front end sides of the side plates 31b, 31c, there are formed a 
first disc pressing portion 62a and a second disc pressing portion 62b for 
allowing the optical disc 101 accommodated within the disc accommodating 
body 2 to undergo pressing operation against biasing force of the disc 
pressing spring 20. These first and second disc pressing portions 62a, 62b 
are adapted so that when the grip mechanism supporting member 31 disposed 
on the disc carrying body 7 is moved on the disc carrying body 7, and is 
admitted into the disc accommodating body 2 through the opening portion 
2c, the first and second disc pressing portions 62a, 62b press at least 
one the other optical disc 101 positioned in a manner adjacent to and in 
upper and lower directions of the optical disc 101 gripped or grasped by 
the grip mechanism 74 in the direction indicated by arrow B.sub.1 in FIGS. 
2 and 11 which is toward the inside of the disc accommodating body 2 
against biasing force of the disc pressing spring 20 to relatively project 
a predetermined one optical disc 101 positioned between other optical 
discs 101 with respect to the other optical disc or discs 101 thus to 
engage a portion of the outer circumferential edge side of the 
predetermined optical disc 101 into the engagement recessed portion 48. 
In this embodiment, as shown in FIG. 12, the first disc pressing portion 
62a positioned at the upper side is formed so as to have a width W.sub.2 
sufficient to press two other optical discs 101 positioned in a manner 
adjacent to the upper side of the optical disc 101 gripped or grasped by 
the disc grip mechanism 74, and the second disc pressing portion 62b 
positioned at the lower side is formed so as to have a width W.sub.3 
sufficient to press three other optical discs 101 positioned in a manner 
adjacent to the lower side of the optical disc 101 gripped or grasped by 
the disc grip mechanism 74. 
Moreover, at the side of the outside surface of the other side plate 31c of 
the grip mechanism supporting member 31, there is provided a disc 
detection sensor 81 for detecting presence of insertion of the optical 
disc 101 into the engagement recessed portion 48. As shown in FIGS. 6 and 
7, this disc detection sensor 81 is of a structure in which a light 
emitting element 81a and a light receiving element 81b are arranged 
oppositely to each other in such a manner that the engagement recessed 
portion 48 is put therebetween. The disc detection sensor 81 serves to 
detect presence of light from the light emitting element 81a by the light 
receiving element 81b to thereby detect whether or not the optical disc 
101 is inserted into the engagement recessed portion 48. 
At the grip mechanism supporting member 31, the grip mechanism 74 is 
attached through the side plates 31b, 31c. As shown in FIGS. 6 and 11, the 
disc grip mechanism 74 comprises a pair of grip arms 24, 25. These grip 
arms 24, 25 are attached so that their middle portions are pivotally 
supported by a support shaft 28 inserted between the pair of side plates 
31b, 31c, the pair of grip arms 24, 25 can be rotated with the support 
shaft 28 acting as the center. At the front end side of the grip arms 24, 
25, disc holding pads 24a, 25a are attached in a manner opposite to each 
other. These disc holding pads 24a, 25a are formed by synthetic resin body 
having elasticity or felt, etc. in order that the optical disc 101 is not 
damaged when the optical disc 101 is held by the disc holding pads 24a, 
25a therebetween. 
In this example, the pair of grip arms 24, 25 are adapted so that when they 
are disposed on the disc carrying body 7, they are attached to the grip 
mechanism supporting member 31 in such a manner that the front end sides 
where the disc holding pads 24a, 25a are attached are opposed to the disc 
accommodating body 2. 
Further, these pair of grip arms 24, 25 are caused to undergo rotational 
operation with the support shaft 28 acting as the center to thereby allow 
the disc holding pads 24a, 25a at the front end portion side thereof to be 
in contact with the optical disc 101 or to be away therefrom so as to grip 
or grasp the optical disc 101, or release of the optical disc 101. 
Moreover, an extension spring 34 is stretched at the back end side of the 
pair of grip arms 24, 25 as shown in FIG. 11, and the extension spring 34 
is rotationally biased in a direction to open the front end side where the 
disc holding pads 24a, 25a are attached. 
Further, at the other end side of the pair of grip arms 24, 25, as shown in 
FIG. 6, a pair of engagement pins 32, 33 are projected toward the lateral 
direction. These engagement pins 32, 33 are adapted so that when the grip 
mechanism supporting member 31 which supports the disc grip mechanism 74 
is attached to the movement member 39, the engagement pins 32, 33 are 
engaged with a cam groove 40 bored through the other side plate 39c of the 
movement member 39. In this example, as shown in FIG. 6, the pair of 
engagement pins 32, 33 are projected toward the other side plate 39c of 
the supporting member 39 through an opening portion 35d bored through the 
other side plate 31c of the grip mechanism supporting member 31. 
The grip mechanism supporting member 31 to which the disc grip mechanism 74 
is attached as described above is disposed in such a manner that it is 
fitted (assembled) between the side plates 39b, 39c of the movement member 
39 in the state where the operation shaft 35 is inserted through the 
elongated hole 52 and the engagement pins 32, 33 of the disc grip 
mechanism 74 are inserted into the cam groove 40. Further, the extension 
spring 76 is stretched between the supporting member 39 and the grip 
mechanism supporting member 31 so that the both members are connected to 
each other. As shown in FIGS. 13 and 14, the movement member 39 which 
supports the grip mechanism supporting member 31 is disposed on the disc 
carrying body 7 in the state where the movement guide shaft 51 is inserted 
through the movement guide groove 61. At this time, the operation shaft 35 
provided at the grip mechanism supporting member 31 supported by the 
movement member 39 is also inserted through the movement guide groove 61. 
The movement guide shaft 51 and the operation shaft 35 are connected to 
the movement guide member 49 disposed at the lower surface side opposite 
to the surface where the movement member 39 is disposed on the disc 
carrying body 7. The movement guide shaft 51 is connected to the movement 
guide member 49 by inserting the movement guide shaft 51 through the 
elongated hole 50 bored through the movement guide member 49, and allowing 
a washer 51a for prevention of slipping off to be fitted with respect to 
the front end side. Moreover, the operation shaft 35 is connected to the 
movement guide member 49 at the front end side of the movement guide 
member 49. By connecting the movement guide shaft 51 and the operation 
shaft 35 to the movement guide member 49 disposed at the lower surface 
side of the disc carrying body 7, the movement member 39 and the grip 
mechanism supporting member 31 hold the disc carrying body 7 therebetween 
in a manner to cooperate with the movement guide member 49. Thus, the 
movement member 39 and the grip mechanism supporting member 31 are 
disposed on the disc carrying body 7 in the state where slipping off from 
the disc carrying body 7 is prevented. Accordingly, the movement member 
39, the grip mechanism supporting member 31 and the movement guide member 
49 are moved on the disc carrying body 7 in one body while being guided by 
the guide groove 61. 
Meanwhile, at respective corner portions of the movement guide member 49, 
as shown in FIG. 6, elastic displacement portions 49a for pressing the 
lower surface side of the disc carrying body 7 are formed so as to extend 
from the respective corner portions of the movement guide member 49. When 
the disc carrying body 7 is held by the movement member 39, the grip 
mechanism supporting member 31 and the movement guide member 49, the 
elastic displacement portions 49a are caused to be elastically in 
pressure-contact with the lower surface of the disc carrying body 7, 
whereby the movement member 39 and the grip mechanism supporting member 31 
are supported on the disc carrying body 7 in a stable state, and are 
supported on the disc carrying body 7 so that they are moved on the disc 
carrying body 7 in a stable state. 
In this example, the movement member 39 is connected to the movement guide 
member 49 in the state where the movement guide shaft 51 is inserted into 
the elongated hole 50 and is permitted to be relatively moved with respect 
to the movement guide member 49 and the grip mechanism supporting member 
31 within the range of the elongated hole 50. 
Further, at the disc carrying body 7, there is provided a movement 
operation mechanism 75 for allowing the movement member 39 to undergo 
movement operation in the direction indicated by arrow E.sub.1 and in the 
direction indicated by arrow E.sub.2 in FIG. 2 along the guide groove 61. 
This movement operation mechanism 75 comprises a drive motor 53 attached 
on the disc carrying body 7, a drive force transmission gear mechanism 55 
composed of plural gears connected to a drive gear 54 attached to the 
drive shaft of the drive motor 53, and a timing belt 56 laid across the 
first and second gears 57, 58. This timing belt 56 is connected to the 
movement member 39 disposed on the disc carrying body 7 by fixing the 
middle portion to a belt connecting portion 47. 
In this example, the drive force transmission gear mechanism 55 is 
connected to the first gear 57 to transmit drive force of the drive motor 
53 to the first gear 57. 
Further, when the drive motor 53 of the movement operation mechanism 75 is 
driven, the timing belt 56 is moved. Thus, the movement member 39 is 
caused to undergo movement operation in the direction indicated by arrow 
E.sub.1 or in the direction indicated by arrow E.sub.2 in FIG. 2 while 
being guided by the guide groove 61 in accordance with the rotational 
direction of the drive motor 53. 
Meanwhile, the grip mechanism supporting member 31 supported by the 
movement member 39 disposed on the disc carrying body 7 is adapted so that 
when it is in the state biased by experiencing biasing force of the 
extension spring 76 so that it can be moved toward the front side of the 
movement member 39 in the direction indicated by arrow G.sub.1 in FIGS. 6 
and 7, there results the state where the pair of engagement pins 33, 32 of 
the disc grip mechanism 74 are respectively engaged with first and second 
inclined groove portions 41, 42 of the cam groove 40 thereby placing the 
optical disc 101 in the state where it can be gripped or grasped, in which 
the front end sides of the first and second grip arms 24, 25 are spaced 
from each other. 
Further, when the grip mechanism supporting member 31 is moved toward the 
backward side of the movement member 39 in the direction indicated by 
arrow G.sub.2 in FIGS. 6 and 7, the engagement pin 44 that is attached to 
the front end of the engagement lever 45 that is attached to the other 
side plate 39c of the movement member 39 rides onto an inclined surface 
portion 38 formed continuously with the engagement recessed portion 37 at 
the backward end side of the upper edge side of the other side plate 31c 
of the grip mechanism supporting member 31. As a result, the engagement 
lever 45 is rotated in the direction indicated by arrow F.sub.2 in FIG. 6 
against biasing force of the torsion coil spring 46. 
When the grip mechanism supporting member 31 is moved toward the backward 
side of the movement member 39 in the direction indicated by arrow G.sub.2 
in FIGS. 6 and 7, the pair of engagement pins 33, 32 of the disc grip 
mechanism 74 are moved to the horizontal groove portion 40a side of the 
cam groove 40 to close the front end sides of the first and second grip 
arms 24, 25 thus allowing gripping or grasping of the optical disc 101 
engaged with the engagement recessed portion 48. 
When the grip mechanism supporting member 31 is further moved toward the 
backward side of the movement member 39 in the direction indicated by 
arrow G.sub.2 in FIGS. 6 and 7, the engagement pin 44 rides across the 
inclined surface portion 38, resulting in the state where it is opposite 
to the engagement recessed portion 37. As a result, the engagement lever 
45 undergoes biasing force of the torsion coil spring 46, and is thus 
rotated in the direction indicated by arrow F.sub.1 in FIG. 6. Thus, the 
engagement lever 45 is engaged into the engagement recessed portion 37. At 
this time, since the engagement pin 44 is engaged with the engagement 
recessed portion 37, the grip mechanism supporting member 31 is prevented 
from moving toward the forward side with respect to the movement member 39 
to maintain the gripped state of the optical disc 101 by the disc grip 
mechanism 74. 
Since the engagement lever 45 is caused to undergo rotational operation in 
the direction indicated by arrow F.sub.2 in FIG. 6 against biasing force 
of the torsion coil spring 46, the engagement pin 44 serves to release the 
engagement with respect to the engagement recessed portion 37, thus 
permitting movement toward the front side in the direction indicated by 
arrow G.sub.1 in FIGS. 6 and 7 with respect to the movement member 39 of 
the grip mechanism supporting member 31. 
Further, on the disc carrying body 7, as shown in FIG. 15, a holding member 
36 and a cam piece 67 are provided in positions on the movement locus of 
the disc drawing mechanism 23. The holding member 36 is provided at the 
position allowing the disc drawing mechanism 23 to move in the direction 
indicated by arrow E.sub.1 in FIG. 15 on the disc carrying body 7 so that 
it is moved to the position close to the disc accommodating body 2 side. 
Upon such movement the operation shaft 35 provided at the movement member 
31 comes into contact with the holding member 36. Moreover, when the disc 
drawing mechanism 23 is moved toward the backward side of the disc 
carrying body 7 in the direction indicated by arrow E.sub.2 in FIG. 15 so 
as to be spaced or away from the disc accommodating body 2 so that it is 
moved to the position where it has completed drawing operation from the 
disc accommodating body 2 of the optical disc 101, the operation shaft 35 
comes into contact with the cam piece 67, and the engagement pin 44 of the 
engagement lever 45 runs or rides onto the inclined surface of the cam 
piece 67. In addition, the engagement lever 45 is rotated in the direction 
indicated by arrow F.sub.2 in FIG. 6 against biasing force of the torsion 
coil spring 46 to release the engagement with respect to the engagement 
recessed portion 37 of the engagement pin 44. 
The operation of the disc drawing mechanism 23 will now be described in 
more practical sense. The disc drawing mechanism 23 including the movement 
member 39 which supports the grip mechanism supporting member 31 to which 
the disc grip mechanism 74 is attached is placed in the state where it is 
moved to the first position which is the withdrawal position spaced, to 
the maximum degree, from the disc carrying body 2 as shown in FIG. 2. At 
this time, the engagement pin 44 attached to the engagement lever 45 is in 
the state where it rides on the cam piece 67 as shown in FIG. 15. Namely, 
there results the state where the engagement lever 45 is rotated in the 
direction indicated by arrow F.sub.2 in FIG. 6 against biasing force of 
the torsion coil spring 46 so that the engagmeent lever 45 is withdrawn 
from the engagement recessed portion 37 of the grip mechanism movement 
member 39. Accordingly, the grip mechanism supporting member 31 undergoes 
biasing force of the extension spring 76, and is thus biased so that it 
can be moved in the direction indicated by arrow G.sub.1 in FIG. 6 with 
respect to the supporting member 31 to project first and second pressing 
portions 62a, 62b provided at the front end portions of side plates 31b, 
31c from the gripping supporting mechanism member 31. 
At this time, the first position detecting switch 63 disposed on the disc 
carrying body 7 is operated by the movement member 39. Thus, it is 
detected that the disc drawing mechanism 23 is located at the first 
position. 
When the drive motor 53 of the movement operation mechanism 75 is driven in 
a forward rotational direction in the state where the disc drawing 
mechanism 23 is located at the first position shown in FIG. 2 which is the 
initial position, the timing belt 56 is traveled in the direction 
indicated by arrow J.sub.1 in FIG. 2 to move the disc drawing mechanism 23 
in the direction indicated by arrow E.sub.1 in FIG. 2 close to the disc 
accommodating body 2. At this time, since the grip mechanism supporting 
member 31 is connected to the movement member 39 through the extension 
spring 76, it is moved in the direction indicated by arrow E.sub.1 in FIG. 
2 in one body with the movement member 39. Moreover, the pair of grip arms 
24, 25 of the disc grip mechanism 74 attached to the grip mechanism 
supporting member 31 are placed in the state where the engagement pins 32, 
33 are respectively engaged with first and second inclined cam grooves 41, 
42 of the cam groove 40 provided at the movement member 39, i.e., in the 
state where the optical disc 101 is permitted to be gripped or grasped, in 
which their front end sides are spaced from each other. 
Further, when the disc drawing mechanism 23 moves in the direction 
indicated by arrow E.sub.1 in FIG. 2 that is the direction close to the 
disc accommodating body 2 from the first position shown in FIG. 2 to reach 
the second position shown in FIG. 16, the first and second pressing 
portions 62a, 62b of the grip mechanism supporting member 31 are caused to 
be admitted into the disc accommodating body 2, the operation shaft 35 
provided at the lower surface side of the bottom plate 31a of the grip 
mechanism supporting member 31 comes into contact with the holding member 
36 provided at the disc carrying body 7 as shown in FIG. 15 to stop the 
grip mechanism supporting member 31 with respect to the disc carrying body 
7. At this time, as shown in FIGS. 16 and 17, the first and second 
pressing portions 62a, 62b provided at the front end portion of the grip 
mechanism supporting member 31 press the optical disc 101 accommodated and 
held within the disc accommodating body 2 in the direction indicated by 
arrow B.sub.1 in FIGS. 16 and 17 which is the direction toward the inside 
of the disc accommodating body 2. At this time, as shown in FIG. 17, the 
optical discs 101 pressed or pushed by the first and second pressing 
portions 62a, 62b are positioned in a manner adjacent to each other in 
upper and lower directions relative to a predetermined optical disc 101 
drawn out. Further, as the result of the fact that the optical discs 101 
are pressed by the first and second pressing portions 62a, 62b, the disc 
pressing spring 20 is pressed by the optical discs 101 so that it is 
caused to undergo elastic deformation in the direction indicated by arrow 
K.sub.1 in FIG. 2. Thus, elastic force for moving the optical discs 101 
which have pressed each disc pressing spring 20 in the direction indicated 
by arrow E.sub.2 in FIG. 17 in the direction to project it from the disc 
accommodating body 1 is stored (accumulated). 
Further, when the first and second pressing portions 62a, 62b press other 
optical discs 101 positioned in a manner adjacent to each other in upper 
and lower directions relative to a predetermined optical disc 101 caused 
to undergo drawing operation, the predetermined optical disc 101 is 
projected from the disc accommodating body 2 with respect to other optical 
discs 101. Thus, the outer circumferential edge portion of the optical 
disc 101 caused to undergo drawing operation is admitted into the 
engagement recessed portion 48 formed at the front end portion of the grip 
mechanism supporting member 31. 
When the disc drawing mechanism 23 is moved to the second position shown in 
FIG. 16, the second position detecting switch 65 disposed on the disc 
carrying body 7 is operated by the movement member 39. Thus, it is 
detected that the disc drawing mechanism 23 has been moved to the second 
position. 
After the disc drawing mechanism 23 has been moved to the second position, 
the drive motor 53 is further driven in the forward rotational direction. 
Thus, the timing belt 56 is traveled in the direction indicated by arrow 
J.sub.1 in FIG. 2. At this time, since the grip mechanism supporting 
member 31 allows the operation shaft 35 to be in contact with the holding 
member 36 provided at the disc carrying body 7 as shown in FIG. 15, there 
results the state where further movement toward the inside of the disc 
accommodating body 2 is limited. Accordingly, only the movement member 39 
moves in the direction indicated by arrow E.sub.1 in FIGS. 16 and 17 
toward the disc accommodating body 2 side. Namely, the movement member 39 
moves in the direction indicated by arrow E.sub.1 in FIGS. 16 and 17 
within the range of the elongated hole 52 with which the movement guide 
shaft 51 provided at the grip mechanism supporting member 31 is engaged. 
Further, when only the movement member 39 is moved in the direction 
indicated by arrow E.sub.1 in FIGS. 16 and 17, since movement following 
the movement member 31 of the grip mechanism supporting member 39 is 
limited, the engagement pins 32, 33 provided at the pair of grip arms 24, 
25 of the grip mechanism 74 are moved toward the horizontal groove portion 
40a side away from the position where the engagement pins 33, 32 are 
respectively engaged with first and second inclined cam grooves 41, 42 of 
the cam groove 40 provided at the movement member 39. Further, the pair of 
grip arms 24, 25 are respectively rotated with the support shaft 28 acting 
as the center in the direction indicated by arrow M.sub.1 and in the 
direction indicated by arrow M.sub.2 in FIGS. 11 and 18 to allow the front 
end portion sides to be close to each other against biasing force of the 
extension spring 33. 
Further, when the drive motor 53 is driven in the forward rotational 
direction so that the movement member 39 is moved in the direction 
indicated by arrow E.sub.1 in FIG. 18, the engagement pins 32, 33 are 
admitted into the horizontal groove portion 40a of the cam groove 40. As a 
result, the pair of grip arms 24, 25 are respectively rotated with the 
support shaft 28 acting as the center in the direction indicated by arrow 
M.sub.1 and in the direction indicated by arrow M.sub.2 in FIG. 18 thus to 
grip or grasp the outer circumferential edge portion of the predetermined 
optical disc 101 engaged with the engagement recessed portion 48 as shown 
in FIG. 19. 
The disc grip mechanism 74 constituting this invention serves to grip or 
grasp, by the pair of grip arms 24, 25, one optical disc positioned 
between optical discs 101 pushed down by the first and second pressing 
portions 62a, 62b, and relatively projected with respect to these optical 
discs 101. Accordingly, it is possible to grip or grasp, from upper and 
lower directions, a predetermined one optical disc 101 from plural optical 
discs 101 accommodated within the disc accommodating body 2 in such a 
manner that they are stacked to each other at intervals (spacings) such 
that the pair of grip arms 24, 25 cannot be admitted. 
Further, after movement of the grip mechanism supporting member 31 is 
limited, only the movement member 31 is moved in the direction indicated 
by arrow E.sub.1 in FIGS. 16 and 17 and the engagement pin 44 of the 
engagement lever 45 attached to the supporting member 39 runs or rides 
onto the inclined surface portion 38 formed at the other side plate 31c of 
the grip mechanism supporting member 31. Further, when the movement member 
31 is moved up to the position where the pair of grip arms 24, 25 grip or 
grasp one optical disc 101, i.e., the third position shown in FIG. 20, the 
engagement pin 44 is engaged with the engagement recessed portion 37 
formed at the other side plate 31c of the grip mechanism supporting member 
31 as shown in FIG. 19. As the result of the fact that the engagement pin 
44 is engaged with the engagement recessed portion 37, movement with 
respect to the movement member 39 of the grip mechanism supporting member 
31 is limited, thereby maintaining the state where the pair of grip arms 
24, 25 have gripped or grasped the optical disc 101. 
When the movement member 39 is moved to the third position shown in FIG. 20 
where it is relatively moved with respect to the grip mechanism supporting 
member 31, a third position detecting switch 66 provided on the disc 
carrying body 7 is operated by the movement member 39. As a result, it is 
detected that the movement member 39 has been moved to the third position. 
Thus, the drive state in the forward rotational direction of the drive 
motor 53 is stopped. 
When it is detected by the third position detecting switch, 66 that the 
movement member 39 has been moved to the third position where the 
predetermined one optical disc 101. accommodated within the disc 
accommodating body 2 is gripped or grasped by the disc grip mechanism 74, 
the drive motor 53 of the movement operation mechanism 75 is once stopped, 
and then begins being driven in a backward rotational direction. When the 
drive motor 53 is driven in the backward rotational direction, the timing 
belt 56 is traveled in the direction indicated by arrow J.sub.2 in FIG. 
20. Thus, the movement member 39 connected to the timing belt 56 is moved 
in the direction indicated by arrow E.sub.2 in FIG. 20 on the disc 
carrying body 7. At this time, since the engagement pin 44 is engaged with 
the engagement recessed portion 37, the grip mechanism supporting member 
31 is moved in the direction indicated by arrow E.sub.2 in FIG. 20 spaced 
or away from the disc accommodating body 2 in one body with the movement 
member 39 while maintaining the state where the predetermined one optical 
disc 101 is gripped or grasped by the disc grip mechanism 74. When the 
drive motor 53 is further driven in the backward rotational direction, the 
grip mechanism supporting member 31 is moved in the direction indicated by 
arrow E.sub.2 in FIGS. 19 and 20 spaced or away from the disc 
accommodating body 2 in one body with the movement member 39 thus to draw 
out, from the disc accommodating body 2, the predetermined one optical 
disc 101 gripped or grasped by the disc grip mechanism 74 as shown in FIG. 
21. 
Further, when the movement member 39 is moved to the fourth position shown 
in FIG. 22 where it has been moved to the first position side relative to 
the central position of the disc carrying body 7, the optical disc 101 
gripped or grasped by the disc grip mechanism 74 is moved to the central 
position on the disc carrying body 7. When the optical disc 101 is moved 
up to the central position of the disc carrying body 7, it is engaged with 
engagement grooves 29a, 30a provided at a pair of left and right disc 
supporting members 29, 30, respectively, provided on the both sides of the 
disc carrying body 7 as shown in FIG. 23. 
Further, when the movement member 39 moves the optical disc 101 gripped or 
grasped by the disc grip mechanism 74 to the fourth position which is the 
drawing position located at the central portion of the disc carrying body 
7, the movement member 39 operates (actuates) a fourth position detecting 
switch 64 disposed on the disc carrying body 7. Thus, it is detected that 
the optical disc 101 has been moved to the fourth position. 
At this time, the operation shaft 35 provided at the grip mechanism 
supporting member 31 comes into contact with the cam piece 67 as shown in 
FIG. 15, thus resulting in the state where movement with respect to the 
disc carrying body 7 is limited. When the drive motor 53 is further driven 
in the backward rotational direction so that the movement member 39 is 
moved in a direction toward the first position which is the initial 
position in the direction indicated by arrow E.sub.2 in FIGS. 21 and 22 
from the fourth position, the engagement pin 44 of the engagement lever 45 
runs or rides onto the inclined surface of the cam piece 67. Further, the 
engagement lever 45 is rotated in the direction indicated by arrow F.sub.2 
in FIG. 6 against biasing force of the torsion coil spring 46 to release 
engagement with respect to the engagement recessed portion 37 of the 
engagement pin 44. When the engagement with respect to the engagement 
recessed portion 37 of the engagement pin 44 is released, the grip 
mechanism supporting member 31 undergoes biasing force of the extension 
spring 76 so that it is relatively moved in the direction indicated by 
arrow G.sub.1 in FIG. 6 within the range of the elongated hole 52 in the 
bottom of the movement member 39. When the grip mechanism supporting 
member 31 undergoes biasing force of the extension spring 76 so that it is 
moved in the direction indicated by arrow G.sub.1 in FIG. 6, the 
engagement pin 44 runs or rides onto the inclined surface portion 38 so 
that it is engaged with the engagement recessed portion 37. At this time, 
as shown in FIG. 2, the grip mechanism supporting member 31 is held at the 
position of the initial state where the first and second disc pressing 
portions 62a, 62b at the front end thereof are caused to be projected from 
the front end of the movement member 39. 
Further, when the grip mechanism supporting member 31 is relatively moved 
in a direction opposite to the movement member 39, the engagement pins 33, 
32 provided at the pair of grip arms 24, 25 of the disc grip mechanism 74 
are moved from the position engaged with the horizontal groove portion 40a 
of the cam groove 40 provided at the movement member 39 toward the 
position engaged with the first and second inclined cam grooves 41, 42, 
respectively. Further, the pair of grip arms 24, 25 undergoes biasing 
force of the extension spring 34 so that they are respectively rotated 
with the support shaft 28 acting as the center in a direction opposite to 
the direction indicated by arrow M.sub.1 and in a direction opposite to 
the direction indicated by arrow M.sub.2 in FIGS. 11 and 24 to allow their 
front end portion sides to be spaced from each other, thereby releasing 
the holding state with respect to the optical disc 101 which has been 
caused to undergo drawing operation. Thus, there results the state where 
the optical disc 101 is mounted on the disc carrying body 7. At this time, 
the optical disc 101 which has been drawn out is supported by the disc 
supporting members 29, 30 so that mounting position onto the disc carrying 
body 7 is maintained. Thus, slipping off from the disc carrying body 7 is 
prevented. 
When the drawing operation of the predetermined optical disc 101 from the 
disc accommodating body 2 is completed, the drive motor of the vertical 
movement operation mechanism 70 begins being driven. When this drive motor 
begins being driven, the timing belt 9 is traveled. Thus, the disc 
carrying body 7 connected to the timing belt 9 is caused to undergo 
movement operation in the direction indicated by arrow D.sub.1 or in the 
direction indicated by arrow D.sub.2 in FIG. 1 perpendicular to the 
principal surface of the optical disc 101 accommodated within the disc 
accommodating body 2 while being guided by the supporting shafts 10, 11. 
At this time, in the case where it is designated that the drawn optical 
disc 101 is loaded with respect to, e.g., the first recording/reproduction 
unit 5, the disc carrying body 7 is moved to the position opposite to the 
first recording/reproduction unit 5. When the disc carrying body 7 is 
moved to the position opposite to the first recording/reproduction unit 5, 
drive of the drive motor of the vertical movement operation mechanism 71 
is stopped and the drive motor 53 of the movement operation mechanism 75 
begins being driven in the forward rotational direction. Thus, the disc 
drawing mechanism 23 is moved in the direction indicated by arrow E.sub.1 
in FIG. 2. Further, the optical disc 101 which has been drawn onto the 
disc carrying body 7 is pressed by the grip mechanism supporting member 31 
in the state where the outer circumferential edge portion is caused to be 
engaged with the engagement recessed portion 48 so that it is moved in the 
direction indicated by arrow E.sub.1 in FIG. 2. Thus, the optical disc 101 
is inserted into the first recording/reproduction unit 5 through the disc 
insertion/withdrawal hole. When the drive motor 53 is further driven in 
the forward rotational direction so that the disc drawing mechanism 23 is 
moved up to the second position shown in FIG. 16, the optical disc 101 
which has been drawn onto the disc carrying body 7 is inserted into the 
first recording/reproduction unit 5. When insertion into the first 
recording/reproduction unit 5 of the optical disc 101 is carried out, the 
loading mechanism provided at the first recording/reproduction unit 5 
starts its operation. As a result, loading operation of this optical disc 
101 is carried out. Thus, recording and/or reproduction of information 
signals with respect to the optical disc 101 is carried out. 
When insertion into the first recording/reproduction unit 5 of the optical 
disc 101 which has been drawn onto the disc carrying body 7 is completed, 
the drive motor 53 of the movement operation mechanism 75 is driven in the 
backward rotational direction to move the disc drawing mechanism 23 in the 
direction indicated by arrow E.sub.2 in FIG. 16 to return the disc drawing 
mechanism 23 to the first position which is the initial position shown in 
FIG. 2. 
In the case where it is designated that the optical disc 101 which has been 
drawn onto the disc carrying body 7 is loaded with respect to, e.g., the 
second recording/reproduction unit 6, the disc carrying body 7 is moved to 
the position opposite to the second recording/reproduction unit 6. By the 
operation similar to the above, insertion and loading with respect to the 
second recording/reproduction unit 6 of the optical disc 101 are carried 
out. Thus, recording and/or reproduction of information signals are 
carried out. 
Moreover, the vertical movement operation mechanism 71 and the disc drawing 
mechanism 23 can be operated (actuated) also when recording and/or 
reproduction of information signals with respect to the optical disc 101 
are being carried out at the first or second recording/reproduction units 
5, 6. For example, in the case where a second optical disc 101 
accommodated within the disc accommodating body 2 is designated after 
insertion of a first optical disc 101 into the first 
recording/reproduction unit 5 is completed, the vertical movement 
operation mechanism 71 moves the disc carrying body 7 up to the position 
opposite to optical disc 101. Following movement of the disc carrying body 
7, the movement operation mechanism 75 is operated (actuated). As a 
result, drawing operation of the second optical disc 101 as described 
above by the disc drawing mechanism 23 is carried out, and loading 
operation with respect to the second recording/reproduction unit 6 of the 
optical disc 101 is carried out. Thus, recording and/or reproduction of 
information signals are carried out. 
Accordingly, the disc recording/reproduction unit according to this 
invention can continuously record and/or reproduce information signals by 
using the first and second recording/reproduction units 5, 6 while 
successively exchanging plural optical discs 101 accommodated and held 
within the disc accommodating body 2. 
Further, when recording and/or reproducing operation of the first or second 
recording/reproduction units 5, 6 into which the optical discs 101 are 
loaded are completed, the vertical movement operation mechanism 71 moves 
the disc carrying body 7 to the position opposite to the first or second 
recording/reproduction unit 5, 6. Following the movement of this disc 
carrying body 7, the movement operation mechanism 75 starts its operation 
to move the disc drawing mechanism 23 to the second position shown in FIG. 
16. When eject operation of the first or second recording/reproduction 
unit 5, 6 is carried out following the movement to the second position of 
the disc drawing mechanism 23, the optical disc 101 loaded with respect to 
the first or second recording/reproduction unit 5, 6 is projected through 
the disc insertion/withdrawal hole to engage the outer circumferential 
edge portion thereof with the engagement recessed portion 48 formed at the 
front end portion of the grip mechanism supporting member 31. The movement 
member 39 of the disc drawing mechanism 23 is further moved to the third 
position side shown in FIG. 20 from the second position shown in FIG. 16 
following the eject operation of the optical disc 101, whereby the grip 
mechanism 74 is operated (actuated) as previously described to carry out 
gripping or grasping of the ejected optical disc 101. When gripping or 
grasping of the optical disc 101 is carried out, the drive motor 53 of the 
movement operation mechanism 75 is driven in the backward rotational 
direction to move the disc drawing mechanism 23 in the direction indicated 
by arrow E.sub.2 in FIG. 22. Thus, drawing operation from the first or 
second recording/reproduction unit 5, 6 of the optical disc 101 is carried 
out by the operation similar to the drawing operation of the optical disc 
101 from the disc accommodating body 2. When the drawing operation onto 
the disc carrying body 7 of the optical disc 101 is completed, the 
vertical movement mechanism 71 starts driving operation to move the disc 
carrying body 7 to the position opposite to the disc supporting portion 18 
of the disc accommodating body 2 within which the optical disc 101 ejected 
from the first or second recording/reproduction unit 5, 6 has been 
accommodated. Following the movement of this disc carrying body 7, the 
drive motor 53 of the movement operation mechanism 75 starts drive 
operation in the forward rotational direction to move the disc drawing 
mechanism 23 in the direction indicated by arrow E.sub.1 in FIG. 22. 
Further, the optical disc 101 which has been drawn out onto the disc 
carrying body 7 is pressed by the disc grip mechanism supporting member 31 
in the state where its outer circumferential portion is engaged with the 
engagement recessed portion 48, so the optical disc 101 is moved in the 
direction indicated by arrow E.sub.1 in FIG. 2. Thus, the optical disc 101 
is accommodated into the disc supporting portion 18. When accommodation 
into the disc supporting portion 18 of the optical disc 101 is completed, 
the disc drawing mechanism 23 is returned to the first position which is 
the initial position. Thus, a series of returning operations of the 
optical disc 101 are completed. 
Moreover, in the case where exchange of any one optical disc 101 
accommodated within the disc accommodating body 2 is designated, the 
vertical movement operation mechanism 71 moves the disc carrying body 7 to 
the position opposite to the optical disc 101 for which exchange is 
designated to carry out drawing operation of this optical disc 101. When 
the drawing operation of the optical disc 101 for which exchange has been 
designated is carried out, the vertical movement operation mechanism 71 
moves the disc carrying body 7 to the position opposite to the disc 
exchange mechanism 3. Following the movement to the position opposite to 
the disc exchange mechanism 3 of the disc carrying body 7, the disc 
drawing mechanism 23 is moved to the disc exchange mechanism 3 side by the 
movement operation mechanism 75 to further move the optical disc 101 which 
has been drawn onto the disc carrying body 7 onto the disc tray 4 of the 
disc exchange mechanism 3. When the optical disc 101 is mounted on the 
disc tray 4, the disc exchange mechanism 3 draws the disc tray 4 toward 
the outside of the outer casing 1 through the insertion/withdrawal hole 
16. Then, exchange of the optical disc 101 mounted on the disc tray 4 is 
carried out by drawing or pulling the disc tray 4 into the outer casing 1 
for a second time to allow the optical disc 101 exchanged by the disc 
drawing mechanism 23 to be mounted on the disc carrying body 7. Then, the 
disc carrying body 7 is moved by the vertical movement mechanism 71 to the 
position opposite to the disc supporting portion 18 at which the exchanged 
optical disc 101 has been accommodated to operate (actuate) the disc 
drawing mechanism 23 to allow the exchanged optical disc 101 to be 
accommodated at the disc supporting portion 18. Thus, exchange of the 
optical disc 101 accommodated in the disc accommodating body 2 is carried 
out. 
The exchange operation of the optical disc 101 accommodated within the disc 
accommodating body 2 can be carried out also when recording and/or 
reproduction of information signals are being carried out at the first and 
second recording/reproduction units 5, 6. 
The operations of the vertical movement operation mechanism 71 and the 
movement operation mechanism 75 described above are controlled on the 
basis of various command signals inputted to the disc 
recording/reproduction unit, and/or control signals from the control unit 
provided within the unit based on detection outputs of first to fourth 
position detecting switches 63, 64, 65, 66. 
The control unit for detecting whether or not optical disc or discs 101 is 
ir are held at respective disc supporting portions of the disc 
accommodating body 2 will now be described. 
As shown in FIG. 25, for example, this control unit comprises a controller 
201 for detecting on the basis of a signal from the disc detection sensor 
81 whether or not the optical disc 101 is held at each disc supporting 
portion 18, a RAM 202 for temporarily storing detection result, etc., and 
a display section 203 for displaying such detection result, etc. 
The controller 201 delivers, e.g., drive pulse for moving the 
above-described vertical movement operation mechanism 71 to the position 
of the first disc supporting portion 18 from the home position toward the 
upper direction to a step motor 211 for driving the vertical movement 
operation mechanism 71, e.g., when the power supply of this disc 
recording/reproduction unit is turned ON or by instruction from the host 
computer. By this drive signal, the step motor 211 rotates by a 
predetermined number of rotations. A frequency generator (hereinafter 
abbreviated as FG) 212 which produces a pulse signal having the number of 
pulses corresponding to the number of rotations is attached to the rotary 
shaft of the step motor 211. The controller 201 counts the number of 
pulses of the pulse signal delivered from the FG 212 to judge whether or 
not the vertical movement operation mechanism 71 reaches the position of 
the first disc supporting portion. 
Further, the controller 201 is operative so that when the vertical movement 
operation mechanism 71 reaches the position opposite to the first disc 
supporting portion 18, it delivers, to the movement operation mechanism 
75, a control signal for advancing the above-described disc drawing 
mechanism 23 from the first position shown in FIG. 2 which is the initial 
position to the drawing position which is the third position shown in FIG. 
20 where drawing operation of the optical disc 101 close to the disc 
accommodating body 2 is carried out. As a result, the disc drawing 
mechanism 23 is moved to the drawing position of the optical disc 101. 
Thus, the disc detection sensor 81 is brought into an OFF state when the 
optical disc 101 is held at the first disc supporting portion 18, and is 
brought into an ON state when the optical disc 101 is not held. The 
controller 201 judges presence of the optical disc 101 on the basis of a 
signal indicating that the optical disc 101 is present (e.g., High level 
corresponding to the OFF state), or is absent (Low level) delivered from 
the disc detection sensor 81. The judgment result is stored in the RAM 202 
in correspondence with the first disc supporting portion 18. Moreover, at 
this time, the controller 201 delivers a control signal for withdrawing 
the disc drawing mechanism 23 to the first position to the movement 
operation mechanism 75. Thus, the disc drawing mechanism 23 is moved to 
the first position. 
Then, the controller 201 repeats the above-described operation while 
delivering, to the step motor 211, a drive pulse for successively moving 
the vertical movement operation mechanism 71 to positions of the 
respective disc supporting portions 18 to judge whether or not the optical 
disc 101 is held at the respective disc supporting portions 18. The 
judgment result is stored in the RAM 202 in correspondence with the 
respective disc supporting portions 18. When detections of presence of the 
optical disc 101 with respect to all disc supporting portions 18 are 
completed, the controller 201 sends, to the host computer, information 
indicating presence of the optical disc 101 stored in the RAM 202, and 
carries out, at this time, a control to return the vertical movement 
operation mechanism 71 to the home position. In addition, the controller 
201 also carries out a control to display the detection result on the 
display section 203. Thus, user can recognize which disc supporting 
portion 18 accommodates the optical disc. 
Namely, in this disc recording/reproduction unit, as the result of the fact 
that the disc detection sensor 81 is provided at the disc drawing 
mechanism 23, it is possible to detect presence of the optical disc 101 
without drawing the optical disc 101 from the disc supporting portion 18. 
In addition, since the drawing operation is not carried out, it is 
possible to detect presence of the optical disc in a short time. In other 
words, in this disc recording/reproduction unit, an approach is employed, 
without drawing the optical disc 101, to move the vertical movement 
operation mechanism 71 to the disc supporting portion 18 to detect 
presence of the optical disc 101, thereby making it possible to detect, at 
a high speed, presence of the optical disc within the disc accommodating 
body 2. 
Moreover, since the disc recording/reproduction unit according to this 
invention is adapted to move the disc drawing mechanism 23 in the 
direction of the disc accommodating body 2, thereby making it possible to 
carry out detection of presence of the optical disc 101, in the case where 
it is detected that the optical disc 101 is not located at the disc 
supporting portion 18, it is possible to immediately shift to the drawing 
operation to the next designated optical disc 101 held at the disc 
supporting portion 18 without carrying out the drawing operation of the 
optical disc 101. Thus, rapid exchange operation of the optical disc 101 
can be realized. 
Another example of a disc grip mechanism 174 will now be described. This 
disc grip mechanism 174 precisely carries out positioning of the grip 
position, thus making it possible to grip or grasp the optical disc 101, 
and to attain more reliable protection of the optical disc 101. 
This disc grip mechanism 174 comprises a pair of grip arms 124, 125 at the 
position where the optical disc 101 is gripped or grasped from upper and 
lower directions of the principal surface thereof similarly to the 
previously described grip mechanism. As shown in FIGS. 26 and 27, these 
pair of grip arms 124, 125 are supported at their central portions by a 
support shaft 128, and are rotatably supported with the support shaft 128 
acting as the center between the pair of grip arms 124, 125. As shown in 
FIGS. 28 to 30, this disc grip mechanism 174 is rotatably attached to a 
grip mechanism supporting member 131 via the support shaft 128. 
Further, at the respective front end portions of the pair of upper and 
lower grip arms 124, 125, there are provided members adapted to have 
ability to prevent that the optical disc 101 is damaged. Namely, at the 
front end portion of the grip arm 124 positioned at the upper side in 
FIGS. 26 and 27, there is attached a disc holding pad 171 for holding the 
label surface at the upper surface side of the optical disc 101. This disc 
holding pad 171 is formed by, e.g., cushion material having high friction 
coefficient such as silicon rubber, etc., and is rotatably attached, as 
shown in FIG. 28, via an attachment shaft 172 to the upper side grip arm 
124 in a manner positioned on the central line O.sub.1 passing through the 
center of the optical disc 101. 
On the other hand, at the front end portion of the lower side grip arm 125, 
in a manner opposite to the disc holding pad 171, as shown in FIGS. 26 and 
27, there is attached a disc holding plate 173 for holding the signal 
reading surface of the lower surface side of the optical disc. This disc 
holding plate 173 is rotatably attached via a spacer 174a and an 
attachment shaft 175 to the lower side grip arm 125 on the center line 
O.sub.1, and is adapted so that a pair of centering projections 176a, 176b 
are provided at left and right symmetrical positions, respectively, with 
the center line O.sub.1 being put therebetween at the disc holding surface 
173a, whereby when the optical disc 101 is gripped or grasped, these 
centering projections 176a, 176b are in contact with the outer 
circumferential edge of the optical disc 101. 
Moreover, while the disc holding plate 173 is adapted as shown in FIGS. 26 
and 27 so that the portion up to the position corresponding to the outer 
circumferential side portion, where no signal is recorded on the signal 
reading surface of the optical disc 101, is caused to be the disc holding 
surface 173a of the same plane. The partial surface corresponding to the 
signal recording portion of the signal reading surface of the optical disc 
101 is caused to be a step portion 173b depressed by one step. For this 
reason, when gripping or grasping the optical disc 101, the disc holding 
plate 173 holds the outer circumferential portion where no signal is 
recorded on the signal reading surface of the optical disc 101, e.g., the 
portion extending from the outer circumferential edge up to the portion 
inwardly positioned by about 1.5 mm in the case of optical disc 101 having 
diameter of 12 cm, and that is not in contact with the signal recording 
portion. 
Further, at the rear (back) portion of the disc holding plate 173, a 
limiting pin 177 is provided as shown in FIG. 27. This limiting pin 177 is 
inserted into a hole portion 178 of a larger diameter formed at the grip 
arm 125 of the lower side. Thus, movement of the disc holding plate 173 is 
limited within the range where the limiting pin 177 is moved within this 
hole portion 178. 
In this example, the disc holding plate 173 is formed by hard resin 
material for the purpose of ensuring the dimensional accuracy and a 
required rigidity. 
Further, as shown in FIG. 26, a torsion coil spring 179 is fitted on the 
support shaft 128. This torsion coil spring 179 is fitted on the support 
shaft 128 in the state where the arm portion of one end side is held by a 
holding piece 180 provided at the upper side grip arm 124 and the arm 
portion of the other end side is held by a holding piece portion 181 
provided at the lower side grip arm 125, whereby the pair of upper and 
lower grip arms 124, 125 are rotatably biased in a direction such that the 
disc holding pad 171 and the disc holding plate 173 are spaced from each 
other. 
Further, at the other end portions of the pair of upper and lower grip arms 
124, 125, engagement pins 133, 132 are respectively provided. As shown in 
FIG. 29, these engagement pins 133, 132 are inserted and engaged with a 
cam groove 140 provided at the movement member 139 constituting a disc 
drawing mechanism 123. 
When the optical disc 101 is drawn out by the disc drawing mechanism 123 
provided with the disc grip mechanism 174 of this embodiment constituted 
as described above, the grip mechanism supporting member 131 is moved 
toward the front side in the state where the disc holding pad 171 and the 
disc holding plate 173 of the upper and lower grip arms 124, 125 are 
spaced from each other as shown in FIG. 29, whereby the disc pressing 
portions 162a, 162b of the front end portion of the grip mechanism 
supporting member 131 press toward the inside of the disc accommodating 
body 2, and two optical discs positioned above and three optical discs 101 
positioned below the optical disc 101 opposite to an engagement recessed 
portion 148 are moved from the position of (a) to the position of (c) 
shown in FIG. 28, resulting in the state where the outer circumferential 
edge portion side of the optical disc 101 opposite to the engagement 
recessed portion 148 is engaged into the engagement recessed portion 148. 
As a result, a pair of centering projections 176a, 176b of the disc 
holding plate 173 come into contact with the optical disc 101 to move the 
optical disc 101 toward the inside of the disc accommodating body 2 from 
the position of (a) up to the position of (b) shown in FIG. 28. 
Since the optical disc 101 moved as the result of the fact that these pair 
of centering projections come into contact therewith is moved against 
biasing force of the disc supporting spring 20 provided at the disc 
accommodating body 2 side, a force resulting from pressure by the disc 
supporting spring 20 on the optical disc 101 is applied to the centering 
projections 176a, 176b. For this reason, the disc holding plate 173 
attached to the lower side grip arm 125 in the rotatable state is caused 
to precisely undergo centering directed to the central direction of the 
optical disc 101 as the result of the fact that the outer circumferential 
edge of the circular optical disc 101 is received by the pair of left and 
right centering projections 176a, 176b. Further, when the movement member 
139 is moved toward the front side directed to the inside of the disc 
accommodating body 2 as shown in FIG. 30 from the above-mentioned state, 
the engagement pins 132, 133 are moved along the cam groove 140 of the 
movement member 139, whereby the pair of upper and lower grip arms 124, 
125 are rotated in the direction where the disc holding pad 171 and the 
disc holding plate 173 are caused to be close to each other, resulting in 
the state where the optical disc 101 is put between both upper and lower 
surface sides. In this state, the label surface of the upper surface side 
of the optical disc 101 is held by the disc holding pad 171 having high 
friction coefficient. Thus, the optical disc 101 is securely gripped or 
grasped by force produced by friction therebetween. 
On the other hand, the signal reading surface of the lower surface side of 
the optical disc 101 is placed in the state where the disc holding plate 
173 holds the outer circumferential side portion where no signal is 
recorded. In this instance, particularly in the disc grip mechanism 174 of 
this embodiment, since the disc holding plate 173 is caused to precisely 
undergo centering by the pair of centering projections 176a, 176b as 
previously described, it is possible to securely hold the outer 
circumferential side portion where no signal is recorded. Accordingly, 
there is no possibility that the signal recording portion of the optical 
disc 101 may suffer from any damage. 
In a manner as described above, the grip mechanism supporting member 131 is 
moved toward the backward side where the grip mechanism supporting member 
131 is spaced or away from the disc accommodating body 2 in the state 
where it grips or grasps the optical disc 101 without damaging the signal 
recording portion, and whereby the optical disc 101 is drawn out from the 
disc accommodating body 2. At this time, since the optical disc 101 is 
gripped or grasped by sufficiently large force by friction between the 
optical disc 101 and the disc holding pad 171, the optical disc 101 is 
securely drawn out from the disc accomodating body 2 without slipping off 
therefrom. 
Moreover, in the case of sending the optical disc 101 back into the disc 
accommodating body 2, the optical disc 101 to be sent back is once pushed 
or thrust into the position of (b) shown in FIG. 28, but is pushed back 
(returned) up to a predetermined accommodating position (a) by force of 
the disc supporting spring 20. 
Also in the case of this example, at the grip mechanism supporting member 
131, there is provided a disc detection sensor for detecting presence of 
the optical disc 101 engaged with the engagement recessed portion 148. 
It is to be noted that disc detection sensors used in the respective 
embodiments are not limited to the sensor of the optical system, but a 
sensor adapted to detect presence of engagement of the optical disc 101 
into the engagement recessed portions 48, 148 by mechanical contact may be 
used. 
In addition, the optical disc 101 accommodated within the disc 
accommodating body 2 is not limited to the optical disc of the 
recording/reproduction type, but may be the optical disc of the 
reproduction only type. In this case, it is sufficient that a unit 
dedicated for reproduction is used as the recording and/or reproduction 
unit. 
While explanation has been given in the above-described respective 
embodiments by taking the example of the disc recording/reproduction unit 
adapted so that optical discs 101 are accommodated within the disc 
accommodating body 2, this invention may be applied to disc recording 
and/or reproduction units using magnetic discs or other discs serving as a 
recording medium for information signals having rigidity to such a degree 
that deformation does not easily take place by pressing operation of the 
disc drawing mechanism, thus making it possible to obtain advantages 
similar to the above-described embodiments. 
Industrial Applicability 
As described above, the disc recording and/or reproducing apparatus 
according to this invention is adapted to move at least another one disc 
adjacent to a predetermined one disc from plural discs accommodated within 
the disc holding body in such a manner that they are stacked toward the 
inside of the holding body against biasing force of the biasing member so 
as to grip or grasp, by the grip mechanism, only the predetermined one 
disc in a projected manner and to draw out it. Accordingly, it is possible 
to securely draw out a predetermined one disc from the disc holding body 
which has held plural discs therewithin. As a result, the interval or 
spacing between discs held within the disc holding body can be reduced. 
Thus, miniaturization of the apparatus itself can be realized.