Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism
Reexamination Certificate
1999-09-29
2002-08-06
Hudspeth, David (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Reexamination Certificate
active
06429993
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to magnetic recording and playing back apparatuses, and more particularly it relates to video tape recorders (VTR) which can record and playback information with a tape packed in a cassette equipped with an ID board.
BACKGROUND OF THE INVENTION
In recent years, digital VTRs have prevailed not only in professional uses but also in consumers' households, and the certain consumers frequently use digital VTRs to their entertainment. This digital VTR employs a digital video cassette and digital video mini-cassette in accordance with a relevant standard. The cassette rear plate where a label is pasted has an ID board including four terminals.
A conventional magnetic recording and playing back apparatus is described hereinafter.
In
FIG. 3
, mechanism
311
is constructed as follows: Rotary-head-drum
321
includes a magnetic head (not shown) for recording or playing back information such as audio and video signals. Drum
321
spins at a given rotating speed. Cassette housing
327
houses a magnetic tape such as a metal evaporated tape (ME tape) or a metal particle tape (MP tape). Housing
327
can also houses a cleaning tape.
Supply reel
317
and take-up reel
319
transport the tape packed in the cassette housing
327
. When the housing
327
is loaded into a VTR, loading posts
313
move from positions
315
to the marked positions thereby pulling the tape out of the housing
327
and winding the tape around drum
321
.
Loading controller
323
instructs loading posts
313
to move the tape. Reel controller
325
instructs supply reel
317
and take-up reel
319
to spin, and at the same time, it also strengthens or moderates a back tension applied to the tape. Controller
329
instructs loading controller
323
to load the cassette tape into the VTR, or instructs reel controller
325
to spin the reel.
An operation of the conventional VTR thus constructed is described hereinafter.
When cassette housing
327
is loaded to mechanism
311
of the VTR, a motor (not shown) coupled to rotary-head-drum
321
is driven, whereby drum
321
starts to spin at a given rotating speed. Reel controller
325
applies a given tape tension (back tension) to the tape, and loading controller
323
instructs posts
313
to pull the tape from locations
315
and wind the tape around drum
321
covering a given angle on drum
321
.
When a cleaning tape is loaded, posts
313
sometimes fail to pull the cleaning tape out of housing
327
, or the tape loading is not completed because drum
321
is prevented from being spun. This troublesome case is described hereinafter. In this case, controller
329
firstly instructs loading controller
323
to unload the tape in order to avoid damaging the tape. Loading controller
323
follows the instruction and retracts posts
313
to positions
315
, thereby restoring the tape into the cassette.
However, the conventional construction described above applies a given back tension to a tape regardless of tape characteristics, so that a difference between the frictional coefficients of different kinds of tapes causes the troubles described above. As a result, the heads of the VTR are not cleaned anymore.
A reason why the cleaning tape cannot be pulled out of the cassette is this: the back tension applied to the cleaning tape by reel controller
325
at the loading is stronger than a force of posts
313
pulling out the tape by loading controller
323
. When a back tension is applied by reel controller
325
based on the ME tape or MP tape having a low surface frictional coefficient, the cleaning tape of which frictional coefficient is high encounters resistance at both the reels in loading. As a result, the cleaning tape cannot be smoothly pulled out of reels
317
and
319
. The resistance and the back tension eventually halt the loading operation of posts
313
.
A reason why drum
321
halts to spin is also a back tension applied to the cleaning tape and resistance due to high frictional coefficient of the cleaning tape. These two factors prevent drum
321
from spinning when the cleaning tape winds around drum
321
, and eventually halt drum
321
to spin.
SUMMARY OF THE INVENTION
The present invention addresses the problems discussed above, and aims to provide a magnetic recording and playing back apparatus having a function to determine a kind of tape and to change a back tension applied to a tape responsive to the kind of tape.
The magnetic recording and playing back apparatus of the present invention can accommodate a cassette on which an ID board is equipped, and from the ID board characteristics of the tape packed in the cassette can be detected. The apparatus comprises the following elements:
(a) a loading controller (a first controller) for instructing a mechanism to pull a tape out of a cassette;
(b) a reel controller (a second controller) for instructing a reel to spin so that a back tension is applied to the tape when the tape is loaded;
(c) an ID board detector for determining a kind of tape based on information from the ID board; and
(d) a third controller for varying the back tension to be applied by the reel controller to the tape responsive to the kind of tape determined by the ID board detector.
This construction allows the magnetic recording and playing back apparatus to accommodate a cassette tape regardless of the tape characteristics.
REFERENCES:
patent: 5390870 (1995-02-01), Sawada et al.
patent: 5481415 (1996-01-01), Oguro
patent: 5726817 (1998-03-01), Oguro et al.
Hudspeth David
Matsushita Electric - Industrial Co., Ltd.
Wong K.
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