JP2000298814A - Magnetic recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an end portion of a recorded track from being overwritten during two-way recording and reproduction of a magnetic tape. SOLUTION: When a magnetic tape T is subjected to two-way recording by means of first and second rotary magnetic head pair (15A, 15B), (15C, 15D), with respect to an attachment height of the first and second rotary magnetic head pair to an upper drum, a displacement from a designed value up to a maximum acceptable attachment error value (d) is accepted, the magnetic tape is allowed to travel in reciprocating directions so as to satisfy the equation TP=2H+d, in which H represents a head track width of the first and second rotary magnetic head pair, and TP represents a track pitch of tracks to be formed on the magnetic tape T by the first and second rotary magnetic head pair. Accordingly, an end section of the track that has been already recorded is not overwritten, and so, satisfactory quality of a reproduced image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device such as a helical scan type VTR which records and reproduces an information signal by a rotary magnetic head by reciprocating a magnetic tape.

[0002]

2. Description of the Related Art Current helical scan type VTRs have only one running direction of the magnetic tape during recording. Therefore, when reproducing the recorded signal, the magnetic tape must be rewound until the start of recording. Therefore, when recording is to be resumed when the magnetic tape has been recorded to the end, the recording must be rewound to the beginning of the magnetic tape, and when endless recording is to be performed, such as in a monitoring VTR, rewinding is required. There is a problem that a recording signal is lost for the operation time.

Therefore, in order to enable continuous recording for a long time in a VTR, an apparatus for recording and reproducing by reciprocating a magnetic tape has been proposed. There are mainly two methods for reciprocating the magnetic tape. As a first method, the recording area of the magnetic tape is divided into two steps in the width direction, and one area is used for recording in the forward direction (forward direction) and the other area is used for recording in the backward direction (reverse direction). Some are used.

However, as a method of dividing the recording area of the magnetic tape into upper and lower stages, it is necessary to move the position of the recording and reproducing head up and down between the forward path and the backward path.
The configuration of the TR mechanism must be significantly changed, which is not very practical.

On the other hand, a second method is disclosed in
As disclosed in Japanese Patent Application Laid-Open No. 0-85316, there is a method in which every other recording track is recorded on the outward path, and is recorded on an unrecorded track area formed between the recorded tracks on the return path.

FIGS. 13 (a) and 13 (b) are a top view and a side view of a main part of a rotating four-head type magnetic recording / reproducing apparatus to which a conventional reciprocating recording / reproducing method can be applied, and FIG. 4
FIG. 15 is a diagram for explaining an operation of reciprocating recording by the head type magnetic recording / reproducing apparatus. FIG. 15 shows one video of a plurality of video heads mounted on a rotating disk in the rotating 4-head type magnetic recording / reproducing apparatus shown in FIG. FIG. 16 shows a state in which the head is mounted displaced by an allowable maximum mounting height error value d with respect to a design value. FIG. 16 shows a rotary disk in the rotating four-head magnetic recording / reproducing apparatus shown in FIG. A track when a magnetic tape is reciprocally recorded by a plurality of video heads in a state where one of the plurality of video heads mounted is displaced by an allowable maximum mounting height error value d with respect to a design value. It is a figure for explaining a pattern, (a) shows a track pattern at the time of going-path recording, and (b) is a track pattern at the time of going-path recording and return trip recording. It is a diagram showing.

As shown in FIGS. 13A and 13B, in a rotating four-head magnetic recording / reproducing apparatus 100 to which a conventional reciprocating recording / reproducing method can be applied, a magnetic tape T is guided by guide poles 101 and 102. And travels in both directions while spirally contacting the outer peripheral surface of the guide drum 103 for approximately 180 °. In addition, the rotating disk 104 is
3, four video heads 105A to 105D are disposed at positions divided by 90 ° on the outer peripheral edge of the rotating disk 104, and are rotatably held between the upper and lower drums 3 in the direction of the arrow.
180 degrees clockwise only by head motor (not shown)
It is rotated at a predetermined speed of 0 rpm.

At this time, as shown in FIG.
The video heads 105A and 105B facing each other at 180 ° apart from each other along the outer peripheral edge of the optical disk 04 have an azimuth angle + α with the gap inclined clockwise from the vertical direction by an angle α °.
° is set. On the other hand, video heads 105A, 1
The gaps of the video heads 105C and 105D, which are 90 ° apart from each other and 05B apart from each other and 180 ° apart from each other, are set at an azimuth angle −α ° with the gap inclined at an angle α ° counterclockwise from the vertical direction. I have.

In FIG. 13, reference numeral 106 denotes an erasing head, and 107 denotes an audio control head.

Then, as shown in FIG. 14A, when the magnetic tape T is recorded while running in the forward direction (forward direction), the video heads 105A and 105B use the track A.
Recording is performed every other track in the order of 1, 1, B1, A2, and B2. At this time, an unrecorded area for one track is left between the recorded tracks so that a track for backward recording can be arranged.

On the other hand, the magnetic tape T is moved in the backward direction (reverse direction).
If the magnetic tape T is simply reversed when recording while traveling, the video heads 105C and 105D traverse the recorded outward track, as shown in FIG. 14B.

Therefore, when recording the magnetic tape T while traveling in the backward direction (reverse direction), first, as shown in FIG. 14C, a track at a reversal position is detected and then a capstan servo circuit (not shown). To stop the capstan motor and correct the tilt angle of the track scanning of the video heads 105C and 105D so as to match the tilt angle at the time of recording in the forward direction. Then, the unrecorded track area formed between the recorded tracks is deleted. Video head 105C to fill
Recording is performed on every other track in the order of tracks C1, D1, C2, and D2 by 105D. At the lower end of the magnetic tape T, a control pulse CP is recorded by the audio control head 107 in synchronism with the rotation of the rotating disk 104 during the outward recording on the magnetic tape T.

[0013]

By the way, in the rotating four-head magnetic recording / reproducing apparatus 100 to which the above-mentioned conventional reciprocating recording / reproducing system can be applied, the video heads 105A to 105A are used.
When recording back and forth on the magnetic tape T in 5D, the azimuth angles of the video heads 105A to 105D are set to be opposite azimuth angles ± α ° between adjacent tracks, so that crosstalk occurs between adjacent tracks. Good recording / reproducing can be performed without generation of blemishes.

However, as the high-density recording on the magnetic tape T progresses and the track becomes narrower, it is required to improve the dimensional accuracy of the mechanical parts in the apparatus. In particular, the video heads 105A to 105A mounted on the rotating disk 104 are required. 105D
Is one of the important factors in forming an accurate track pattern on the magnetic tape T, but it is still difficult to manage it in microns.

As described above, a track recorded by running the magnetic tape T in the backward direction (reverse direction) is provided between the tracks (forward direction tracks) recorded by running the magnetic tape T in the forward direction (forward direction). (Return track), the narrower the track, the more the video head 10
The mounting height error of 5A to 105D becomes a problem that cannot be ignored.

Here, video heads 105A to 105D
15 and FIG.
This will be described with reference to (a) and (b).

In FIG. 15, the mounting heights of the video heads 105A to 105D mounted on the rotating disk 104 are all set to the same height in design, and
Assuming that the head track width of the video heads 105A to 105D is H and the track pitch is TP, the track pitch TP during reciprocal recording is represented by 2H in design. However, among the video heads 105A to 105D, for example, the video head 105B is mounted so as to be shifted downward by an allowable maximum mounting height error value d which is a maximum value of an allowable mounting error with respect to a designed mounting height. If
When the magnetic tape T is recorded on the outward path by the video heads 105A and 105B, the video head 105B is located at a position d lower than the normal mounting height, and therefore, FIG.
As shown in the figure, the narrow guard band (GB in the figure)
1) is Hd, and the wider guard band (G in the figure)
B2) becomes H + d.

On the other hand, as shown in FIG. 16B, the magnetic tape T on which the forward path has been recorded is placed on the video heads 105C and 105C.
In the case of the backward recording in 5D, the backward recording track recorded in the narrower guard band overwrites the edge of the outward recording track by the width d, while the backward recording track recorded in the wider guard band. The tracks are arranged in close contact with the outward recording tracks and have no margin.

From the above, if there is a deviation in the mounting height between the video heads 105A and 105B for recording the forward path,
The width of the unrecorded area (the so-called guard band) becomes non-uniform by that amount, and every other place wider and narrower than the head track width H of the video heads 105A and 105B is formed. For this reason, the video head 1 for homeward recording
Even if the tracks 05C and 105D attempt to form a track in the unrecorded area, where the width of the unrecorded area is smaller than the head track width H, the edge of the outward track is inevitably gripped to overlap the edge of the recorded track. I will write.

In addition, the video head 105 for homeward recording
If the mounting heights of C and 105D are also displaced, there is a problem that the track area on which overwriting is performed further increases and the reproduction image quality is further reduced.

Therefore, when a magnetic tape is reciprocally recorded / reproduced by a video head (rotating magnetic head), the mounting height of the video head (rotating magnetic head) on the rotating drum is an allowable maximum mounting height error with respect to a design value. There is a demand for a magnetic recording / reproducing apparatus that does not overwrite the edge of a recorded track when displacement to the value is allowed.

[0022]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has been made in a state where a magnetic tape is helically wound around a rotating drum to which a plurality of rotating magnetic head pairs are attached over a predetermined angle. A magnetic recording / reproducing apparatus that reciprocally records and reproduces information signals on the magnetic tape by the plurality of pairs of rotating magnetic heads while transferring the magnetic tape at a predetermined speed in a reciprocating direction; A first rotating magnetic head pair mounted at 180 ° apart along a second rotating head mounted at 180 ° apart along the outer peripheral surface of the rotating drum at a position different from the first rotating magnetic head pair A rotary drum assembly rotatably supporting the rotary drum, which is provided with a pair of magnetic heads intersecting about a drum axis, and a head traverse of the first and second rotary magnetic head pairs The click width is H, and, first, second
When the mounting height of the pair of rotary magnetic heads to the rotary drum is allowed to move up to an allowable maximum mounting error value d with respect to a design value, the first and second rotary magnetic head pairs are mounted on the magnetic tape. The track pitch TP of the track is T
An information signal is transmitted by magnetic tape running means for running the magnetic tape in the reciprocating direction so as to satisfy the relational expression of P = 2H + d, and one of the first and second rotating magnetic head pairs. Tracks are recorded every other track on the magnetic tape that is being transported in the forward path, and after the forward path recording, the magnetic tape is reversed in the backward path so that tracks formed between tracks that have been recorded by the one rotating magnetic head pair. Means for recording an information signal every other track in the area by the other rotating magnetic head pair, a recording locus in the forward direction by the one rotating magnetic head pair, and a recording locus in the backward direction by the other rotating magnetic head pair. And a means for making the same.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic recording / reproducing apparatus according to the present invention will be described below in detail with reference to FIGS.

FIG. 1 is an overall configuration diagram for explaining a magnetic recording / reproducing apparatus according to the present invention.

As shown in FIG. 1, a magnetic recording / reproducing apparatus 1 according to the present invention employs a helical scan system using a rotating magnetic head, and a first and a second rotating magnetic tape are applied to a reciprocating magnetic tape T. Head pair (15A, 15B),
(15C, 15D), a rotary magnetic head assembly 10 for performing reciprocal recording and reproduction of information signals, a capstan 2 and a pinch roller 3 for transporting the magnetic tape T in the forward and backward directions, and a tape (not shown) for the magnetic tape T A pair of tape loading members 4 and 4 movably provided on the left and right sides of the rotary magnetic head assembly 10 so as to be drawn out of the cassette and spirally wound around the rotary magnetic head assembly 10 at a predetermined angle (approximately 180 °). A control head 5 provided on the right side of the rotary magnetic head assembly 10 for recording and reproducing a control pulse CP (FIG. 9) at the lower end of the magnetic tape T; and a system control circuit 6 for controlling the overall operation of the apparatus 1. , A capstan servo circuit 7 for controlling the transfer of the magnetic tape T, and controlling the drive and tilt angle of the rotary magnetic head assembly 10 And Ramusabo circuit & inclination angle correction unit 8, is schematically a signal processing block 9 for processing signals of the recording and reproducing.

The above-described capstan servo circuit 7 controls the driving of the capstan 2 and the control head 5 based on a control signal from the system control circuit 6, and sends a control signal to the capstan 2 to 2
While the magnetic tape T is sandwiched by the pinch roller 3 and the magnetic tape T, the transfer control of the magnetic tape T in the reciprocating direction is performed at a predetermined speed during reciprocal recording and reproduction. Further, at the time of reciprocal recording / reproducing to / from the magnetic tape T, the capstan servo circuit 7 performs the first and second rotating magnetic head pairs (15A,
15B) and (15C, 15D), the height of attachment to the rotating drum (hereinafter referred to as the upper drum) 14 was allowed to be displaced from a design value to an allowable maximum attachment error value d (FIGS. 11 and 12). The speed of the magnetic tape T is controlled in consideration of the case.

During recording on the magnetic tape T in the forward direction, a control pulse is recorded at the lower end of the magnetic tape T by the control head 5 in synchronization with the rotation of the rotary magnetic head assembly 10, and the forward direction is recorded. The recording is performed by changing the duty of the control pulse only when the control pulse is reversed from the homeward direction or from the homeward direction to the forward direction. During recording on the magnetic tape T in the backward direction and during reciprocal reproduction on the magnetic tape T, the traveling of the magnetic tape T is performed via the capstan servo circuit 7 using the control pulse reproduced by the control head 5. The control is performed so as to be the same as in the direction recording, and the control pulse whose duty is changed is detected to perform the inversion operation.

The above-described drum servo circuit & angle correction unit 8
Is connected to a drum control motor or the like of the rotary magnetic head assembly 10 and controls the drum rotation at a predetermined rotation speed by a drum servo circuit 8A (FIG. 5), as described later. ), The inclination angle correction control of the rotary magnetic head assembly 10 is performed. By this tilt angle correction control, the first and second rotating magnetic head pairs (15
A, 15B) and (15C, 15D), the recording locus in the forward direction (forward direction) by the pair of rotating magnetic heads and the recording locus in the backward direction (reverse direction) by the other rotating magnetic head pair. Are matched.

The above-mentioned signal processing block 9 is connected to the first and second pairs of rotary magnetic heads (15A, 15B) and (15C, 15D) attached to the rotary magnetic head assembly 10, and performs signal processing for recording and reproduction. I do.

Next, the rotary magnetic head assembly 10 described above
Will be described with reference to FIGS.

FIG. 2 is a longitudinal sectional view showing a rotary magnetic head assembly which is a main part of the present invention, FIG. 3 is an exploded perspective view showing the rotary magnetic head assembly, and FIGS. FIG. 5 is a top view for explaining the first and second pairs of rotating magnetic heads attached to the rotating magnetic head assembly, and a mounting position diagram. FIG. 5 is a configuration diagram schematically showing the entire configuration of the rotating magnetic head assembly.
6A to 6C are schematic diagrams for explaining the operation of the rotary magnetic head assembly, and FIG. 7 shows the relationship between the entire drum correction, the primary correction, and the secondary correction in the rotary magnetic head assembly. FIG.

The rotary magnetic head assembly 10 described above is an essential part of the present invention. The rotary magnetic head assembly 10 can be used by the applicant when performing variable speed reproduction (high-speed search reproduction, slow reproduction, still reproduction). DD that allows the rotating magnetic head to follow the recording marks on the magnetic tape so that no band noise occurs on the screen even if the rotating magnetic head reproduces across the recording marks (signal tracks) recorded on the magnetic tape.
(Dynamic Drum) system, this DD system is applied to the reciprocating recording / reproducing operation on the magnetic tape T in the present embodiment, and the rotating magnetic head assembly 10
The first and second rotating magnetic head pairs (15A, 1
5B) and (15C, 15D).

As shown in FIGS. 2 and 3, DD (Dyn
The configuration of a rotary magnetic head assembly 10 employing an amic drum system includes a drum base 11 fixedly mounted on a chassis base (not shown).
1, a lead ring 12, a lower drum 13, and an upper drum (rotary drum) 14 are assembled in this order from below to above.

First, on the outer periphery of the upper drum 14, a tape sliding contact surface 14a for winding and guiding the magnetic tape T over a predetermined angle (approximately 180 °) is formed in a cylindrical shape. A pair of first and second rotating magnetic heads (15A, 15B) and (15C, 15D) are mounted close to the lower drum 13 along the surface 14a.

Here, as shown in an enlarged manner in FIGS. 4A and 4B, the first rotating magnetic head pair (15A, 15B)
Are mounted 180 degrees apart from each other along the outer peripheral surface of the upper drum 14 so as to face each other.
For A and 15B, the gap is inclined clockwise from the vertical direction by an angle α °, and is set to a predetermined azimuth angle + α °. At this time, specifically, each rotating magnetic head 15
The predetermined azimuth angle + α ° of A and 15B is, for example, +6
° is set.

The second rotating magnetic head pair (15C,
15D) are attached 180 degrees apart from each other along the outer peripheral surface of the upper drum 14 and 90 degrees apart from the first rotating magnetic head pair (15A, 15B). , Each rotating magnetic head 15
C and 15D have their gaps inclined counterclockwise by an angle α ° from the vertical direction, and are set to a predetermined azimuth angle −α °. At this time, specifically, the predetermined azimuth angle −α ° of each of the rotating magnetic heads 15C and 15D is set to −6 °, for example.

Here, the first rotating magnetic head pair (15
A, 15B) and the second rotating magnetic head pair (15C, 15C).
D) is mounted on the upper drum 14 so as to intersect with the drum shaft 16 as a center, and the second rotating magnetic head pair (15A, 15B) has a second azimuth angle α ° with respect to a predetermined azimuth angle α °. The predetermined azimuth angle -α ° of the pair of rotating magnetic heads (15C, 15D) is reverse azimuth.

In this embodiment, the first rotating magnetic head pair (15A, 15B) and the second rotating magnetic head pair (15
C, 15D) means 90 along the outer peripheral surface on the upper drum 14.
も の Although they are mounted apart from each other, they are not limited to this, and they may be mounted at different positions. If the traveling of the magnetic tape T is controlled so that the backward recording track can be recorded between the forward recording tracks during the backward recording. Good thing.

Further, the first and second rotating magnetic head pairs (1
The head track widths of 5A, 15B) and (15C, 15D) are set to H, and the track locus on the magnetic tape T is formed by the head track width H.

Next, a drum shaft 16 is press-fitted into the center of the lower drum 13.
4 is coaxially supported via upper and lower bearings 17,17. A magnetic tape T is provided around the lower drum 13.
The tape sliding surface 13a for winding and guiding the
Is formed in a cylindrical shape with substantially the same diameter as the tape sliding contact surface 14a. In the lower drum 13, a small-diameter portion 13b having a smaller diameter than the tape sliding contact surface 13a is formed spirally below the tape sliding contact surface 13a, and has a smaller diameter than the small-diameter portion 13b below the center of the bottom surface portion 13c. A lower small diameter portion 13d is formed so as to protrude toward a drum base 11 described later.

Only the upper drum 14 to which the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D) are integrally mounted is a drum motor 18 (FIG. (Shown) can be rotated in the direction of the arrow. At this time, the drum motor 18
Is a stator 18a fixed to the upper end side of the drum shaft 16.
And a rotor 18b that rotates integrally with the upper drum 14. Also, signals of the first and second pairs of rotary magnetic heads (15A, 15B) and (15C, 15D) are transmitted between the rotary transformer 19 mounted on the upper drum 14 and the rotary transformer 20 mounted on the lower drum 13. Have been giving and receiving.

Further, below the outer periphery of the lower drum 13, a lead ring 12 having a spiral lead 12a for guiding a reference edge Te at the lower end of the magnetic tape T is provided separately from the lower drum 13. I have. The lead ring 12 is
As shown in FIG. 3 in an enlarged manner, the lead 12a having a lead angle γ is fitted at the upper end of the lead 12a with a predetermined angle at the upper end thereof in a state of being close to the outer peripheral surface of the spirally formed small diameter portion 13b. It is roughly composed of an annular portion 12b and a bottom portion 12c formed spirally over an angle. A central hole 12d is formed in the center of the bottom surface portion 12c of the lead ring 12 so as to penetrate therethrough. An inner peripheral portion of the central hole 12d is coaxially fitted with the lower small diameter portion 13d of the lower drum 13. A knife edge portion 12e to be formed is formed. Therefore, the upper and lower drums 14 and 13 coaxially supported by the drum shaft 16 are
The lead ring 12 can be coaxially fitted on the bottom surface 12c. Further, on the upper surface of the bottom surface portion 12 c of the lead ring 12, the first rotation fulcrums 12 f and 12 on the left side as shown in FIG.
f and right second rotation fulcrums 12g, 12g protrude forward and backward in the depth direction, respectively, and these left first fulcrum 12f, 12f and right second fulcrum 12g, 1g.
2g is in contact with the back surface of the bottom portion 13c of the lower drum 13 so as to be able to come and go as described later. A drum base 1 described below is provided on the bottom surface 12 c of the lead ring 12.
1, a left first fulcrum 11c formed on the upper surface 11a,
Four through-holes 12h are drilled for the entry of 11c and the right-hand second pivot points 11d, 11d. Also,
On a bottom surface portion 12c of the lead ring 12, a first geared screw 21, which will be described later, is symmetrical about the drum shaft 16,
Evacuation holes 12i, 12i into which the second member 22 enters, and a second
Screw holes 12j, 12 into which screws 23, 24 with gears are screwed
j is formed.

Next, a drum base 11 serving as a base of the rotary magnetic head assembly 10 is fixedly installed below a lead ring 12. The drum base 11 is provided with a lower drum 13 at the center of the upper surface 11a, as shown in FIG.
A central escape hole 11b into which the lower small diameter portion 13d enters is formed, and the first rotation fulcrums 11c on the left and the second rotation fulcrums 11d on the right are symmetrically symmetrical about the drum shaft 16. 11d protrude forward and backward in the depth direction, respectively. These left first fulcrum 11c, 11
c and the right second rotation fulcrum 11d, 11d penetrate through four through holes 12h of the lead ring 12 and contact with the back surface of the bottom portion 13c of the lower drum 13 in a manner to be described later. In contact. Further, screw holes 11e, 11e into which first geared screws 21, 22 described later are screwed into the drum base 11 symmetrically about the drum shaft 16, and second geared screws 23, 24 described later enter. Through holes 11f are formed respectively.

As shown in FIG. 5, a compression spring 2 is provided between the drum base 11 and the lead ring 12 and between the drum base 11 and the lower drum 13, respectively.
5, 26 and 27 are mounted so that the above-mentioned parts are connected to each other in a predetermined state. The compression springs 25, 26, and 27 shown in the figure are functionally shown, and are provided at predetermined mounting portions.

The drum servo circuit 8A of the drum servo circuit & tilt angle correction section 8 of the rotary magnetic head assembly 10 controls the upper drum 14 at a constant rotation speed in accordance with a command from the system control circuit 6. At the same time, the tilt angle correction unit 8 which describes DD control information corresponding to various operation modes as described below.
B.

On the other hand, the inclination angle correction section 8B is provided with a DD motor (inclination angle driving motor) 8B1 as a power source, and a reduction gear composed of a plurality of gears connected to the left and right with the DD motor 8B1. Mechanisms 8B2 and 8B3 and a rotary encoder 8B4 for detecting rotation of the DD motor 8B1
And a preset sensor 8B5 for detecting the position of the speed reduction mechanism 8B2.

At this time, the left reduction mechanism 8B2 is engaged with the first and second geared screws 21 and 23, and the right reduction mechanism 8B3 is engaged with the right first and second geared screws 22 and 2.
4 is engaged.

Further, a preset sensor 8B for position detection
As 5, for example, a configuration in which an arc-shaped light shielding plate is moved in an optical path in which a light emitting element and a light receiving element are arranged to face each other may be used. The preset sensor 8B5 outputs a signal output from the preset sensor 8B5 at the moment when the arc-shaped light shielding plate is removed from the optical path where the light emitting element and the light receiving element are arranged to face each other. It is used as information indicating the reference position of the drum shaft 16 of the three-dimensional object 10 and the reference position of the lead ring 12.

The amount of rotation of the light shielding plate from the reference position in the preset sensor 8B5 is
By knowing from the measurement of the number of output pulses from B4, the direction and amount of deviation of the rotary magnetic head assembly 10 from the reference position of the drum shaft 16 and the direction and amount of deviation of the lead ring 12 from the reference position are determined. You can ask.

The above-described tilt angle correction unit 8B moves the drum shaft 16 of the rotary magnetic head assembly 10 including the upper drum 14, the lower drum 13, and the lead ring 12 in the direction of arrow R or the direction of arrow L in FIG. The first and second geared screws 21 and 23 are tilted by predetermined amounts, respectively.
And a control operation for moving the right and second geared screws 22 and 24 forward and backward.

The lead ring 12 is also tilted by a predetermined amount in a predetermined direction under the control of the tilt angle correction unit 8B.
Thus, regardless of whether the traveling direction of the magnetic tape T is the forward direction or the backward direction, the magnetic tape T is determined by the rotation locus of the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D). The recording trace (signal track) drawn on T has a predetermined track angle, that is, a state in which the inclination angle has been corrected, and the lead 12a of the lead ring 12 moves along the movement locus of the reference edge Te of the magnetic tape T. Are matched.

As described above, by the operation of the tilt angle correction section 8B, the rotation trajectories of the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D) rotating in a predetermined direction are obtained. The reciprocating recording / reproducing operation can be performed by setting the angle (track angle) between the magnetic tape T and the reference edge Te at a predetermined angle.

Next, the operation of the rotary magnetic head assembly 10 having the above configuration will be described in more detail with reference to FIGS. 6 (a) to 6 (c) and FIG. Note that the inclination angle correction unit 8B
Is used for variable speed reproduction during normal forward recording / reproducing. Here, the description will be made by applying the tilt angle correction unit 8B during reciprocating recording / reproducing.

First, as schematically shown in FIG.
When recording / reproducing the magnetic tape T in the forward direction, the drum shaft 16 is held in a neutral state, and the upper and lower drums 14 and 13 coaxially supported by the drum shaft 16 and the lead ring 12 are connected to the drum base. It is held substantially parallel to the drum base 11 without tilting with respect to the drum base 11. That is, the left and right first and second pivot points 1 on the drum base 11
1c, 11d and the left and right first and second rotation fulcrums 12f, 2g on the lead ring 12 correspond to the bottom portion 13 of the lower drum 13.
c is in contact with the back surface. At this time, the left and right first gear-equipped screws 21 and 22 screwed to the drum base 11 are retracted downward without contacting the bottom surface 13 c of the lower drum 13, while the right and left first geared screws 21 and 22 screwed to the lead ring 12. The two-gear screws 23 and 24 are also retracted downward without contacting the bottom surface 13c of the lower drum 13. Also, the lower drum 13
Due to the strong urging force of the compression spring 27 (FIG. 5) tightly mounted between the drum base 11 and the lower drum 13, the drum base 11
The compression spring 2 is biased toward the side and the lead ring 12 is tightly fitted between the drum base 11 and the lead ring 12.
Since the lower drum 13 is pressed toward the lower drum 13 by a weak urging force of 5, 26 (FIG. 5), the lower drum 13 is reliably supported on the above-mentioned four pivot points while maintaining its height. At the same time, the lead ring 12 is also securely supported while maintaining its height. Therefore, the drum shaft 16 and the virtual drum shaft of the lead ring 12 match with high accuracy, and these shafts are perpendicular to the drum base 11.
In this state, when reproducing the magnetic tape T recorded on the outward path, the magnetic tape T moves its reference edge Te to the read ring 12.
Traveling at a predetermined speed guided by the lead 12a of
First and second rotating magnetic head pairs (15A, 15B),
The rotation locus of (15C, 15D) coincides with the recording trace (signal track) recorded on the magnetic tape T.

Next, as schematically shown in FIG.
When performing the backward recording on the magnetic tape T on which the outward recording is performed, the drum shaft 16 is tilted in the direction of arrow R in order to make the rotational trajectory of the rotational magnetic head of the backward recording follow the rotational trajectory of the rotating magnetic head recorded on the outward path. If you want to record
The DD motor 8B1 (FIG. 5) is driven to rotate the left and first gear-equipped screws 21 and 23 in a direction to push them upward. At this time, the right first and second geared screws 22,
Numeral 24 rotates in the direction of retreating from the lower drum 13 to reverse the rotation direction of the first and second geared screws 21 and 23 on the left.

That is, when the left first geared screw 21 screwed to the drum base 11 is pushed upward, the upper end pushes up the left bottom surface portion 13 c of the lower drum 13. Right second fulcrum 11
d, the right bottom surface portion 13c of the lower drum 13 abuts, while the left first fulcrum 11 on the drum base 11
c is separated from the left bottom surface portion 13c of the lower drum 13. As a result, the upper and lower drums 14, 13 coaxially supported on the drum shaft 16 together with the lead ring 12, resist the urging force of the compression spring 27 (FIG. 5), and the second pivot 11d on the drum base 11. Rotate clockwise around.

Accordingly, the upper and lower drums 14, 13 coaxially supported on the drum shaft 16 together with the lead ring 12, rotate clockwise by the entire drum correction inclination angle θ shown in FIG. As a result, the entire drum is corrected, and the inlet side of the winding of the magnetic tape is displaced upward and the outlet side is inclined so as to be displaced downward.

Also, at the same time when the first geared screw 21 is pushed out, the left second geared screw 23 screwed to the lead ring 12 is also pushed upward in FIG. Abuts on the bottom surface 13c on the left side of the lower drum 13 due to this reaction force.
c is in contact with the first rotating fulcrum 12f on the left side of the lead ring 12 and the bottom surface 13 on the left side of the lower drum 13.
Separate from c. As a result, the bottom surface portion 13c on the left side of the lead ring 12 is centered on the right second rotation fulcrum 12g on the lead ring 12 against the lower drum 13 against the urging force of the compression spring 25 (FIG. 5). The primary correction (track correction) is performed by rotating counterclockwise by the primary correction tilt angle (track correction tilt angle) θ1 shown in FIG.

This primary correction (track correction) is performed by using the recording trace formed on the magnetic tape T and the rotation trajectory surfaces of the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D). So that the lower drum 13
In the direction in which the lead ring 12 is pressed down,
By rotating the lead ring 12 in a direction opposite to the direction of the correction of the entire drum, the magnetic tape is displaced in opposite directions on the entrance side and the exit side of the winding.

Then, the first screwed to the drum base 11
From the correction inclination angle θ of the entire drum by the geared screw 21, 1 is set by the second geared screw 23 screwed to the lead ring 12.
By subtracting the next correction tilt angle (track correction tilt angle) θ1, the lead ring 12
(Secondary correction inclination angle (lead correction inclination angle) θ2). This secondary correction (lead correction) is performed by the lead 12 a of the lead ring 12.
Of the magnetic tape T and the lead ring 12 with respect to the drum base 11 in the direction opposite to each other on the entrance side and the exit side of the winding of the magnetic tape. Incline by the minute. This secondary correction is 1
The magnetic tape T is pulled in the direction of the rotation by the rotation of the rotary magnetic head assembly 10 accompanying the next correction, so that the reference edge Te is connected to the lead 12a on the entrance side of the magnetic tape T with respect to the rotary magnetic head assembly 10. The lead edge 12 is rotated to adjust the lead 12a to the reference edge Te of the magnetic tape T because the reference edge Te tends to be pressed against the lead 12a on the exit side.

Here, even when the secondary correction is performed,
The lead 12a and the first and second rotating magnetic head pairs (15
A, 15B) and (15C, 15D) of course keep the relative angles with respect to the rotation locus plane.

Therefore, even if the reference edge Te of the magnetic tape T is separated from the lead 12a by the primary correction, the reference edge Te of the magnetic tape T is transferred to the rotary magnetic head assembly 10 by the lead 12a by the secondary correction. When the magnetic tape T runs, the first and second rotating magnetic head pairs (15A, 15A) are guided stably over the entire winding range.
The rotation trajectories B) and (15C, 15D) coincide with recording marks (signal tracks) recorded on the magnetic tape T.

Next, as schematically shown in FIG.
When performing the backward path recording on the magnetic tape T on which the forward path recording is performed, the drum shaft 16 is tilted in the direction of the arrow L so that the rotational path of the rotational magnetic head of the backward path recording may follow the rotational path of the rotational magnetic head recorded on the forward path. If you want to record
The DD motor 8B1 (FIG. 5) is driven in a direction opposite to the case where the drum shaft 16 is tilted in the direction of the arrow R to rotate the right first and second geared screws 22 and 24 in a direction to push them upward. And the first and second geared screws 21 and 2 on the left side
3 is rotated in a direction to retract from the lower drum.

That is, when the right first geared screw 22 screwed to the drum base 11 is pushed upward, the upper end pushes up the right bottom surface portion 13 c of the lower drum 13. Left first pivot 11
c contacts the left bottom surface portion 13 c of the lower drum 13, while the right second rotation fulcrum 11 on the drum base 11.
d is separated from the right bottom surface portion 13c of the lower drum 13. As a result, the upper and lower drums 14, 13 coaxially supported on the drum shaft 16 together with the lead ring 12, the first rotation fulcrum 11c on the drum base 11 against the urging force of the compression spring 27 (FIG. 5). Rotate counterclockwise around
The whole drum correction is performed.

Further, at the same time when the first geared screw 22 is pushed out, the right second geared screw 24 screwed to the lead ring 12 is also pushed upward in FIG. Abuts on the right bottom surface portion 13c, the reaction force causes the left first rotation fulcrum 12f on the lead ring 12 to move from the lower drum 13 to the left bottom surface portion 13c.
c on the other hand, the right second rotation fulcrum 12 g on the lead ring 12 is connected to the right bottom portion 13 of the lower drum 13.
Separate from c. Thus, the right bottom surface portion 13c of the lead ring 12 pushes down on the lower drum 13 against the urging force of the compression spring 26 around the left first rotation fulcrum 12f on the lead ring 12 (see FIG. (Clockwise) to perform primary correction.

Then, the first screwed to the drum base 11
The secondary correction of the lead ring 12 with respect to the drum base 11 is performed by subtracting the primary correction by the second gear screw 24 screwed to the lead ring 12 from the entire drum correction by the gear screw 22.

Next, the relationship between the drum overall correction, the primary correction, and the secondary correction described above will be further described with reference to FIG.

That is, in FIG. 7, the entire drum correction inclination angle θ is the first geared screw 2 screwed to the drum base 11.
This is an angle at which the upper and lower drums 14, 13 integrated with the drum shaft 16 together with the lead ring 12 are to be inclined with respect to the drum base 11. The primary correction inclination angle θ1 is determined by the second geared screw 23 (or 24) screwed to the lead ring 12,
The correction angle between the lead 12a of the lead ring 12 and the rotation locus plane of the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D), that is, according to the running speed of the magnetic tape T. , Lead ring 1 for lower drum 13
This is an angle at which the second lead 12a should be inclined in a direction opposite to the inclination direction of the entire drum correction.

On the other hand, as described above, with the primary correction, the magnetic tape T has its reference edge Te
There is a tendency to move away from the lead 2a or to be pressed against the lead 12a. Looking at this tendency, for example, when the drum shaft 16 is inclined in the direction of arrow R, the upper and lower drums 14 and 13
Of the magnetic tape T with respect to the upper and lower drums 14 and 13 by the clockwise rotation with respect to the lead 12a, the magnetic tape T tends to be lifted upward and separated from the lead 12a. , 13
On the exit side of the magnetic tape T, the magnetic tape T tends to be pulled downward and pressed against the leads 12a.

The upper and lower drums coaxially supported on the drum shaft 16 together with the lead ring 12 with respect to the drum base 11 in order to correct such a tendency and make the reference edge Te of the magnetic tape T coincide with the lead 12a. The secondary correction inclination angle θ2 is the angle at which the primary correction angles 14, 14 are to be finally tilted in substantially the same direction as the primary correction inclination angle θ1. The secondary correction tilt angle θ2 is an angle obtained by subtracting the primary correction tilt angle θ1 from the entire drum correction tilt angle θ. In other words, the relationship is θ2 = θ−θ1 (θ = θ1 + θ2).

Next, the signal processing circuit 9 described above,
The second rotating magnetic head pair (15A, 15B), (15
C, 15D) will be described with reference to FIG.

FIG. 8 is a diagram showing a configuration for transmitting and receiving information signals between the signal processing circuit and the first and second pairs of rotating magnetic heads.

In FIG. 8, reference numeral 38 denotes an input terminal of an information signal to be recorded in the magnetic recording / reproducing apparatus 1 according to the present invention, and 39 denotes a magnetic tape T by the magnetic recording / reproducing apparatus of the present invention. This is an output terminal for the information signal reproduced from.

When the information signal supplied to the input terminal 38 is, for example, a video signal, the signal processing circuit 40 of the recording system converts the signal in the form of a frequency-modulated wave by a luminance signal into a low-frequency conversion carrier. A recording signal in the form of a frequency multiplexed signal with a color signal is supplied to the recording amplifiers 41 and 42. The output signal from the recording amplifier 41 is
The output signal from the recording amplifier 42 is supplied to the recording-side fixed contact R in the recording / reproduction switch 46. The reproduction signal from the magnetic tape T is amplified by the preamplifiers 43 and 44 from the reproduction-side fixed contact points P in the recording and reproduction changeover switches 45 and 46, respectively, and is subjected to predetermined signal processing in the reproduction-system signal processing circuit 50. Output from the output terminal 39.

When the magnetic recording / reproducing device is set to the recording operation mode, the recording / reproducing changeover switches 45 and 46 set the movable contact v on the recording side fixed by a switching control signal given from the system control circuit 6. When the magnetic recording / reproducing apparatus is set to the reproducing operation mode, the movable contact v is switched to the reproducing-side fixed contact P by a switching control signal given from the system control circuit 6. Is switched to

The movable contacts v of the recording / reproduction changeover switches 45 and 46 are connected to the movable contacts v of the rotary magnetic head selection switches 47 and 48. The fixed contact A of the rotary magnetic head selection switch 47 is connected to a rotary magnetic head 15A having an azimuth angle + α ° provided on the upper drum 14 via a rotary transformer (not shown). The fixed contact C of the rotary magnetic head selection switch 47 is connected to the rotary magnetic head 1 having an azimuth angle -α ° provided on the upper drum 14.
5C is connected via a rotary transformer (not shown). On the other hand, the fixed contact B of the rotary magnetic head selection switch 48 is connected to the rotary magnetic head 15B provided on the upper drum 14 and having the azimuth angle + α °.
Are connected via a rotary transformer (not shown). The rotary magnetic head selection switch 4
The fixed contact D at 8 is connected to a rotary magnetic head 15D having an azimuth angle -α ° provided on the upper drum 14 via a rotary transformer (not shown).

The rotary magnetic head selection switch 47,
The movable contacts v at 48 are fixed contacts A and B at the time of forward recording by a switching control signal given from the system control circuit 6.
Side (or the fixed contacts C and D sides) and are switched to the fixed contacts C and D sides (or the fixed contacts A and B sides) at the time of return recording.

Next, the recording / reproducing operation of the magnetic recording / reproducing apparatus 1 according to the present invention having the above configuration will be described with reference to FIGS. 1, 5, 8 and 9 to 12.

FIG. 9 is a view showing a recording track pattern reciprocally recorded by the magnetic recording / reproducing apparatus according to the present invention, and FIG. 10 is a view showing the first and second rotations attached to the upper drum in the magnetic recording / reproducing apparatus according to the present invention. FIG. 11 is a diagram for explaining an allowable maximum mounting height error value d of the magnetic head pair. FIG. 11 shows one of the first and second rotating magnetic head pairs mounted on the upper drum in the magnetic recording and reproducing apparatus according to the present invention. FIG. 12 is a view showing a state in which the rotary magnetic head is mounted by being displaced by an allowable maximum mounting height error value d with respect to a design value. FIG. 12 shows a magnetic recording / reproducing apparatus according to the present invention, in which The first and second rotations of the magnetic tape are performed in a state in which one of the rotating magnetic heads of the first and second rotating magnetic head pairs is mounted so as to be displaced from the design value by an allowable maximum mounting height error value d. FIGS. 7A and 7B are diagrams for explaining a track pattern when reciprocating recording is performed by a pair of air heads, in which FIG. 7A illustrates a track pattern during forward recording, and FIG. FIG.

First, the first and second rotating magnetic head pairs (1
5C, 15D) and (15C, 15D), the magnetic tape T is spirally wound around a predetermined angle (approximately 180 °) around the upper drum (rotating drum) 14 in the reciprocating direction. At a predetermined speed.
Here, the predetermined speed at which the magnetic tape T is phased in the reciprocating direction will be described later.

First, at the time of outward recording on the magnetic tape T,
As shown in FIG. 8, the recording / reproduction changeover switches 45 and 46 are switched to the recording side, and the rotary magnetic head selection switch 4
The rotary magnetic heads 15A and 7A having an azimuth angle + α ° are controlled by the switching control signal from the system control circuit 6 to control the magnetic heads 7 and 48.
And a rotating magnetic head 15B having an azimuth angle + α °
Has been switched to the side.

Then, as shown in FIG.
At the time of outward recording to the first pair, the first rotating magnetic head pair (15
A, 15B) to the magnetic tape T
.. Are recorded on every other track in the order of tracks A1, B1, A2, B2, A3,. At this time, the control pulse CP is recorded on the lower end of the magnetic tape T by the control head 5 in synchronization with the rotation of the upper drum 14, and the control pulse CP is recorded near the end point of the outward recording.
Is recorded while changing the duty.

Thereafter, when recording the magnetic tape T in the backward direction by reversing the magnetic tape T in the backward direction (reverse direction), first, the outward recording is stopped, the magnetic tape T is immediately reversed, and the magnetic tape T is reversed in the backward direction. The transfer is started, and the capstan 2 and the capstan servo circuit 7 start controlling the magnetic tape T in the backward direction. At this time, the control in the backward direction of the magnetic tape T is performed by reproducing the control pulse CP recorded on the outward path. The return track is positioned. At substantially the same time as above, the tilt angle correction unit 8B is operated to record the recording trajectory of the first rotating magnetic head pair (15A, 15B) in the forward direction (positive direction) and the second rotating magnetic head pair (1).
5C, 15D), the inclination angle of the rotating drum assembly 10 is corrected so that the recording trajectory in the backward direction (reverse direction) according to (5C, 15D) matches.

At the time of homeward recording on the magnetic tape T, as shown in FIG.
7 and 48 are controlled by a switching control signal from the system control circuit 6 to rotate the magnetic head 15C having an azimuth angle of -α °.
And a rotating magnetic head 15D having an azimuth angle -α °
The recorded track recorded by the first pair of rotating magnetic heads (15A, 15B) while controlling the speed of the magnetic tape T with reference to the recorded control pulse CP as shown in FIG. The second rotating magnetic head pair (15C, 15C) is placed in the unrecorded track area formed between
The information signal input in D) is recorded on the magnetic tape T in the order of tracks C1, D1, C2, D2,... Every other track. At this time, the first rotating magnetic head pair (15
A, 15B), the unrecorded track area formed between the already-recorded tracks is formed only during the first outward recording with the magnetic tape T in a virgin state.
After this, the information signal has already been recorded.

Similarly, by repeating the magnetic tape T a plurality of times in the reciprocating direction, continuous reciprocating recording and reproduction can be performed.

The state shown in FIG. 9 is described using the first pair of rotating magnetic heads (15A, 15B) during forward recording and using the second pair of rotating magnetic heads (15C, 15D) during backward recording. However, conversely, using the second pair of rotating magnetic heads (15C, 15D) during forward recording and using the first pair of rotating magnetic heads (15A, 15B) during backward recording does not cause any problem. .

Here, after the reciprocating recording on the magnetic tape T, the adjacent tracks have the opposite azimuth angles, so that good recording and reproduction can be performed with almost no crosstalk interference from the adjacent tracks. . The reciprocating reproduction to and from the magnetic tape T is performed by the recording / reproduction switches 45 and 46.
Is switched to the reproducing side, and substantially the same operation as that at the time of recording is performed, so that the detailed description is omitted.

Next, as shown in FIGS. 10A to 10D, the first and second rotating magnetic head pairs (15A, 15B),
The variation in the mounting height of (15C, 15D) to the upper drum 14 is kept within a range of an allowable maximum mounting height error value d with respect to a design value that is a normal mounting height. If the height error value d is out of the range, the recording / reproducing characteristics become poor, so that it is determined not to use it.

In the embodiment shown in FIG. 10A, the rotating magnetic head 15B of the first rotating magnetic head pair (15A, 15B) is located below the design value by an allowable maximum mounting height error value d. This is the case where the rotary magnetic head 15 is displaced to the position, and the form shown in FIG.
B is a case where it is displaced and mounted at a position above the design value by an allowable maximum mounting height error value d.
Similarly, in the embodiment shown in FIG. 10C, the rotating magnetic head 15D of the second rotating magnetic head pair (15C, 15D)
FIG. 10 shows a case in which the actuator is displaced to a position below the design value by an allowable maximum installation height error value d, and
The configuration shown in (d) is a case in which the rotating magnetic head 15D is mounted so as to be displaced to a position above the design value by an allowable maximum mounting height error value d.

In the magnetic recording / reproducing apparatus according to the present invention, any one of the first and second pairs of rotating magnetic heads (15A, 15B) and (15C, 15D) attached to the upper drum 14 is rotated. It is assumed that the magnetic head is mounted so as to be displaced from the design value by an allowable maximum mounting height error value d. In this case, the edges of the recorded tracks are overlapped during reciprocal recording on the magnetic tape T. We take measures to prevent writing.

That is, as shown in FIG.
4 and the first and second rotating magnetic head pairs (15
A, 15B) and (15C, 15D), for example, it is assumed that the rotary magnetic head 15B is mounted so as to be displaced downward by the allowable maximum mounting height error value d with respect to the design value, and The second rotating magnetic head pair (15A,
15B), the head track width of (15C, 15D) is H
Then, the track pitch TP of the track on the magnetic tape T is set to TP = 2H + d during reciprocal recording.

At this time, the first and
The second rotating magnetic head pair (15A, 15B), (15
C, 15D) is rotating at a constant speed,
The magnetic tape T driven to be sandwiched between the capstan 2 and the pinch roller 3 is controlled by the capstan servo circuit 7 to a predetermined speed such that the track pitch TP during reciprocal recording is TP = 2H + d.

Then, as shown in FIG.
Rotating magnetic head pair (15A, 15B) with magnetic tape T
When the forward magnetic recording is performed, since the rotating magnetic head 15B is mounted so as to be displaced downward by the allowable maximum mounting height error value d with respect to the design value, the narrower guard band (GB1 in the figure) becomes H, The wider guard band (GB2 in the figure) is H + 2d.

As shown in FIG. 12 (b), when the second rotating magnetic head pair (15C, 15D) performs backward recording on the magnetic tape T, the narrower guard band (GB in the figure) is used.
The backward recording track recorded in 1) is accurately arranged in the gap between the outward recording tracks. On the other hand, the return track recorded on the wider guard band (GB2 in the figure) has a space on both sides by the width d between it and the outward track, and the mounting height is shifted by d from the normal position. Even so, there is no problem.

Of course, in any of the cases shown in FIGS. 10A to 10D, the head track width of the first and second rotating magnetic head pairs (15A, 15B) and (15C, 15D) is set to H. And the upper drum 1 of the first and second pairs of rotating magnetic heads (15A, 15B), (15C, 15D)
The first and second rotating magnetic head pairs (15A, 15B), (15C, 15D) when the mounting height of the magnetic head 4 is allowed to move to the allowable maximum mounting error value d with respect to the design value.
Pitch TP of the tracks on the magnetic tape T due to
If the magnetic tape is run in the reciprocating direction so as to satisfy the relational expression of TP = 2H + d, it is possible to obtain good reproduction image quality because the edges of the recorded tracks are not overwritten.

The technical idea of the present invention can be implemented by an analog recording system such as a well-known VHS system as a recording signal system or a digital recording system.

[0097]

According to the magnetic recording / reproducing apparatus of the present invention described in detail above, when reciprocally recording a magnetic tape with the first and second pairs of rotary magnetic heads, particularly, the first and second rotary magnetic heads are used. The head track width of the pair is H, and the mounting height of the first and second rotary magnetic head pairs to the rotary drum is the maximum allowable mounting error value d with respect to the design value.
When the displacement is allowed, the pitch track T of the track on the magnetic tape by the first and second rotating magnetic head pairs
Since the magnetic tape is run in the reciprocating direction so that P satisfies the relational expression of TP = 2H + d, it is not necessary to overwrite the edge of the recorded track, so that good reproduction image quality can be obtained. is there.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram for explaining a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a longitudinal sectional view showing a rotary magnetic head assembly which is a main part of the present invention.

FIG. 3 is an exploded perspective view showing the rotating magnetic head assembly.

FIGS. 4A and 4B are a top view and a mounting position diagram for explaining first and second rotating magnetic head pairs mounted on the rotating magnetic head assembly.

FIG. 5 is a configuration diagram schematically showing the entire configuration of the rotating magnetic head assembly.

FIGS. 6A to 6C are schematic diagrams for explaining the operation of the rotary magnetic head assembly.

FIG. 7 is a diagram showing a relationship among the entire drum correction, the primary correction, and the secondary correction in the rotating magnetic head assembly.

FIG. 8 is a diagram showing a configuration for transmitting and receiving information signals between a signal processing circuit and first and second pairs of rotating magnetic heads.

FIG. 9 is a diagram showing a recording track pattern recorded reciprocally by the magnetic recording / reproducing apparatus according to the present invention.

FIG. 10 is a view for explaining an allowable maximum mounting height error value d of the first and second rotating magnetic head pairs mounted on the upper drum in the magnetic recording and reproducing apparatus according to the present invention.

FIG. 11 shows a magnetic recording / reproducing apparatus according to the present invention in which one of the first and second pairs of rotating magnetic heads mounted on the upper drum has an allowable maximum mounting height error value d with respect to a design value. It is a figure showing the state where it was displaced and attached.

FIG. 12 shows a magnetic recording / reproducing apparatus according to the present invention in which one of the first and second pairs of rotating magnetic heads mounted on the upper drum has an allowable maximum mounting height error value d with respect to a design value. FIG. 9 is a diagram for explaining a track pattern when the magnetic tape is reciprocally recorded by the first and second rotating magnetic head pairs in a state where the magnetic tape is displaced and attached;
(A) shows a track pattern at the time of forward recording, and (b)
FIG. 8 is a diagram showing a track pattern at the time of return recording when the forward recording is completed.

13A and 13B are a top view and a side view of a main part of a rotating four-head magnetic recording / reproducing apparatus to which a conventional reciprocating recording / reproducing method can be applied.

14 is a diagram for explaining an operation of reciprocating recording by the rotating four-head type magnetic recording / reproducing apparatus shown in FIG.

FIG. 15 is a view showing a rotating four-head magnetic recording / reproducing apparatus shown in FIG. 13, in which one of a plurality of video heads mounted on a rotating disk is displaced by an allowable maximum mounting height error value d with respect to a design value; FIG. 4 is a view showing a state where the display panel is attached as a base.

16 is a diagram illustrating a rotary four-head type magnetic recording / reproducing apparatus shown in FIG. 13, in which one of a plurality of video heads mounted on a rotary disk is displaced by an allowable maximum mounting height error value d with respect to a design value. FIG. 7 is a diagram for explaining a track pattern when a magnetic tape is reciprocally recorded by a plurality of video heads in a state where the magnetic tape is mounted,
(A) shows a track pattern at the time of forward recording, and (b)
FIG. 8 is a diagram showing a track pattern at the time of return recording when the forward recording is completed.

[Description of Signs] 1 ... magnetic recording / reproducing apparatus, 2 ... capstan, 3 ... pinch roller, 5 ... control head, 6 ... system control circuit, 7 ... capstan servo circuit, 8 ... drum servo circuit & tilt angle correction unit , 8A ... drum servo circuit, 8B ...
Inclination angle correction unit, 9: signal processing block, 10: rotating magnetic head assembly, 11: drum base, 12: lead ring, 13: lower drum, 14: rotating drum (upper drum), 15A, 15B: first Rotating magnetic head pair, 15
C, 15D: second rotating magnetic head pair, 16: drum shaft, + α °: azimuth angle of first rotating magnetic heads 15A, 15B, −α °: second rotating magnetic heads 15C, 15
Azimuth angle of D, d: maximum allowable mounting error value, H: head track width of the first and second rotating magnetic head pairs, T:
Magnetic tape, TP: Track pitch.

Claims (1)

[Claims] The magnetic tape is transported at a predetermined speed in a reciprocating direction in a state where the magnetic tape is spirally wound around a rotating drum to which a plurality of rotating magnetic head pairs are attached at a predetermined angle. A magnetic recording / reproducing apparatus for reciprocally recording and reproducing an information signal on and from the magnetic tape by using a pair of rotating magnetic heads, comprising: a first rotating magnetic head pair mounted at 180 ° apart along an outer peripheral surface of the rotating drum; A second rotating magnetic head pair mounted at a position different from the first rotating magnetic head pair at a distance of 180 ° along the outer peripheral surface of the rotating drum; A rotary drum assembly rotatably supporting a drum; a head track width of the first and second rotary magnetic head pairs being H; When the mounting height to the transfer drum is allowed to move up to the allowable maximum mounting error value d with respect to the design value, the track pitch TP of the track on the magnetic tape by the first and second rotating magnetic head pairs is set to TP. = 2H + d, a magnetic tape running means for running the magnetic tape in the reciprocating direction so as to satisfy the relational expression, and an information signal is forwarded by either one of the first and second rotating magnetic head pairs. A track area formed between tracks recorded by one of the rotating magnetic head pairs is recorded on the magnetic tape being transported in the other direction every other track, and after the outward recording, the magnetic tape is reversed in the backward path. Means for recording an information signal every other track by the other rotating magnetic head pair, and a recording locus in the forward direction by said one rotating magnetic head pair. Magnetic recording and reproducing apparatus characterized by comprising a means to match the backward direction of the recording track by the other rotary magnetic head pairs.