Dynamic magnetic information storage or retrieval – Head – Head accessory
Reexamination Certificate
2002-01-25
2004-06-15
Klimowicz, William (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head accessory
C360S084000, C360S128000
Reexamination Certificate
active
06751057
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a recording/reproducing apparatus and a rotary head drum device, and particularly to a recording/reproducing apparatus and a rotary head drum device in which recording and/or reproducing is performed by winding a tape shaped recording medium around the periphery of a rotary drum and bringing a head fitted to the rotary drum into contact with the tape shaped recording medium.
Helical scan type recording/reproducing apparatuss are widely used as a VTR (Video Tape Recorder) or a data tape recorder. Such a recording/reproducing apparatus includes a rotary drum and a fixed drum, and a magnetic head is so fitted as to front on the outer peripheral surface of the rotary drum. A magnetic tape is helically wound around the outer peripheral surfaces of the rotary drum and the fixed drum, and the rotary drum is rotationally driven, whereby the magnetic head scans skewly on the magnetic tape. According to such a helical scan type recording/reproducing apparatus, mutually parallel tracks are sequentially formed on the magnetic tape in a direction inclined relative to the longitudinal direction of the magnetic tape, and recording and/or reproducing of signals is performed by such tracks.
FIG. 7
shows a major portion of such a helical scan type recording/reproducing apparatus, in which a pair of magnetic heads
2
are fitted to a rotary drum
1
, for example, at positions spaced apart by 180 degrees in the circumferential direction. A roller guide
3
and an inclined guide
4
are disposed on the inlet side for introducing a magnetic tape
7
, and a roller guide
5
and an inclined guide
6
are disposed on the outlet side of the magnetic tape
7
.
In such an arrangement, the magnetic tape
7
is slowly fed in sliding contact on the outer periphery side of the rotary drum
1
while being guided by the roller guide
3
and the inclined guide
4
, and is taken out of the rotary drum
1
by the inclined guide
6
and the roller guide
5
. With the rotary drum
1
rotated, the magnetic head
2
is brought into sliding contact with the magnetic tape
7
, and writing or reading of signals is performed by application of the principle of magnetic induction or the principle of electromagnetic induction.
In the helical scan type recording/reproducing apparatus using such a rotary drum
1
, the rotary drum
1
is driven to rotate counterclockwise, namely, in the same direction as the feeding direction of the magnetic tape
7
as shown in FIG.
7
. At this time, air is taken in as indicated by arrow
8
by the outer peripheral surface of the rotary drum
1
, and the air penetrates into the space between the rotary drum
1
and the magnetic tape
7
, forming an air film. Here, when the amount of the air is large, the magnetic tape
7
is swollen largely to the outer periphery side on the downstream side of the inclined guide
4
at the point where the magnetic tape
7
starts making contact with the magnetic head
2
, as indicated by the two-dotted chain line in FIG.
7
.
FIG. 8
shows the variation in the thickness of an air film formed between the outer peripheral surface of the rotary drum
1
and the magnetic tape
7
by the airflow indicated by arrow
8
, from the inlet side to the outlet side of the magnetic tape
7
. As is clear from the graph, the thickness of the air film is particularly large on the inlet side of the magnetic tape
7
. Due to the large thickness value, the magnetic head
2
and the magnetic tape
7
are spaced apart largely from each other at the inlet side portion of the magnetic tape
7
, so that the RF output waveform is lowered than a sufficient value at the starting side portion, as shown in FIG.
6
.
In order to dissolve the lowering of the output due to taking-in of airflow
8
attendant on the rotation of the rotary drum
1
, Japanese Patent Laid-open No. 2000-132890 discloses an apparatus in which an outer peripheral surface of the rotary drum
1
is provided with a plurality of grooves in the circumferential direction. Alternatively, Japanese Patent Laid-open No. 2000-251352 discloses an apparatus in which an air guide is skewly provided in the vicinity of the inclined guide
4
in proximity to the outer peripheral surface of the rotary drum
1
.
The problem of floating of the magnetic tape
7
to the outer periphery side due to the airflow
8
mentioned above is rarely generated where the rotational speed of the rotary drum
1
is low. In addition, the floating to the outer periphery side can be prevented by giving a sufficient tension to the magnetic tape
7
. In this case, therefore, it is needless to restrain the flowing-in of the airflow
8
. When the rotational speed of the rotary drum
1
is raised in order to achieve a high transfer rate, however, the amount of floating of the magnetic tape on the inlet side increases, and this phenomenon cannot be dissolved by tape tension. This is because of the problem that the life of the magnetic tape is lowered when tape tension is raised under the condition where the rotational speed is high.
Therefore, it is necessary to lower the tape tension. Where the tape tension is low, the floating cannot be restrained by simply providing the outer peripheral surface of the rotary drum
1
with the grooves as disclosed in Japanese Patent Laid-open No. 2000-132890. An apparatus having a propeller type or an intermediate drum rotation type of drum construction in place of the combination of a rotary drum and a fixed drum is somewhat advantageous against the above-mentioned problems, but such an approach leads to a rise in cost on the construction basis or worsening of assemblability. Besides, such an approach is poor in reworkability, and is unsuitable for positive adoption.
An apparatus of providing a guide plate skewly at a position on the direct downstream side of an inlet-side inclined guide as disclosed in Japanese Patent Laid-open No. 2000-251352 suffers the problem that the air pressure at the portion on the upstream side of the guide plate is locally abnormally raised since the air taken in by the rotary drum is compressed by the guide plate. Besides, there is the problem that the air has a negative pressure at a position on the downstream side of the guide plate, so that it is impossible to stably control the air film.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned problems. Accordingly, it is an object of the present invention to provide a recording/reproducing apparatus and a rotary head drum device in which it is possible to reduce the thickness of the air film at the portion on the inlet side of a tape shaped recording medium and to control the thickness of the air film to be substantially uniform.
In accordance with one aspect of the present invention, there is provided a recording/reproducing apparatus, together with a rotary head drum device therefor, for performing recording and/or reproducing by winding a tape shaped recording medium around the periphery of a rotary drum and bringing one or more heads fitted to the rotary drum into contact with the tape shaped recording medium, wherein a guide plate is provided for restraining air flowing along the rotational direction of the rotary drum around the periphery of the rotary drum on the upstream side with respect to the rotational direction of the rotary drum in relation to the position where the head and the tape shaped recording medium start making contact with each other.
Here, an edge of the guide plate on the upstream side with respect to the rotational direction of the rotary drum may strip the airflow flowing in the rotational direction of the rotary drum and may release the stripped airflow to the side of the outer periphery. Of the guide plate, the edge on the upstream side with respect to the rotational direction of the rotary drum may be wedge-shaped, and the outer peripheral surface may be a guide surface for releasing the air. In addition, the guide plate may be provided with an extended portion for controlling the airflow flowing into the space be
Fujimori Motoyoshi
Hashimoto Ichiro
Itou Akira
Klimowicz William
Maioli Jay H.
LandOfFree
Magnetic recording/reproducing apparatus and rotary head... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Magnetic recording/reproducing apparatus and rotary head..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic recording/reproducing apparatus and rotary head... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3363322