JP3099866B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type magnetic recording / reproducing apparatus. The present invention relates to a magnetic recording / reproducing apparatus that enables a head to trace a recording mark on a magnetic tape in a satisfactory manner.

[0002]

2. Description of the Related Art A magnetic tape wound around a part of a peripheral surface of a drum structure composed of an upper drum and a lower drum is caused to run at a predetermined running speed to form a rotating magnetic head (hereinafter simply referred to as a "magnetic head"). A video tape recorder (hereinafter, referred to as "VTR") is a typical example of a magnetic recording / reproducing apparatus that performs a recording / reproducing operation by performing a helical scan using "."

[0003] In this type of VTR, in addition to normal reproduction (hereinafter referred to as "normal reproduction") in which recorded information is reproduced at the same magnetic tape traveling speed as during recording, the traveling speed of the magnetic tape during recording, and the like. The function of so-called variable speed reproduction (hereinafter referred to as "trick play") in which a reproducing operation is performed by running a magnetic tape in a running speed (including stop) or a running direction different from the running direction is widely adopted.

Further, as in time lapse or so-called frame shooting, a magnetic tape is run intermittently to record an event for a long time, and the recorded magnetic tape is reproduced at, for example, a standard speed. VT that can do
R is also provided.

FIG. 1 is a view showing a general example of a running system of a magnetic tape in the vicinity of a drum structure of a VTR, and FIG.
FIG. 3 shows the relationship between the recording trace pattern recorded on the magnetic tape and the rotation locus of the magnetic head during trick play. FIG. 4 shows the recording of the magnetic tape in a W-VHS VTR. FIG. 4 is a diagram illustrating a relationship between a trace pattern and a rotation locus of a magnetic head during trick play.

A VTR (magnetic recording / reproducing apparatus) shown in FIG.
In FIG. 1, a magnetic tape T is supplied from a supply reel (not shown), and a supply-side guide roller 4 and a supply-side inclined pole 5 supported by a supply-side loading base 3 movable on a chassis base 2; The upper drum 11 is moved by a take-up side inclined pole 7 and a take-up side guide roller 8 supported by a take-up side loading base 6 which can move upward.
And a lower drum 12 is wound around the drum structure 10A obliquely over a predetermined angle range and travels.
It is wound on a take-up reel (not shown) via a known traveling system.

At this time, a recording trace pattern (hereinafter referred to as a "tape pattern" or "track pattern") as shown in FIG. 3 is formed on the magnetic tape T by the magnetic heads 13a and 13b attached to the upper drum 11. You.

In FIG. 1, a straight line connecting a point labeled "Starting Point" on the lower edge of the magnetic tape T, a point labeled +1 on the upper edge of the magnetic tape T, and a number of lines parallel to this line Indicate the center of each track pattern. When the magnetic tape T on which such a track pattern is formed is reproduced while being transported at the same speed in the same direction as during recording, the magnetic heads 13a and 13b trace these tracks and perform normal reproduction. Will be performed.

However, if the traveling speed and direction of the magnetic tape T during reproduction are different from those during recording, the relative linear velocity between the magnetic tape T and the magnetic heads 13a and 13b changes.
Track patterns drawn on the magnetic tape T by the magnetic heads 13a and 13b are, for example, FF and STIL shown in FIG.
L and FB are different.

In FIG. 3, each line drawn when connecting the position of each point shown as +2, +3... +7 and the starting point is the same direction as the running direction of the magnetic tape T during recording. (Indicated by a plus sign), a case where the magnetic tape T is run at a running speed twice, three times,...
This is called "FF playback." 3) shows the rotation locus of the magnetic heads 13a and 13b drawn on the magnetic tape T.

Similarly, each straight line drawn when connecting the position of each point indicated as -2, -3... -7 and the starting point is opposite to the running direction of the magnetic tape T during recording. In the direction (indicated by a minus sign), the traveling speed of the magnetic tape T is twice, three times... Seven times the traveling speed of the magnetic tape T during recording.
Is running and a fast reverse playback operation is performed (hereinafter, referred to as
This is called “FB playback”. 3) shows the rotation locus of the magnetic heads 13a and 13b drawn on the magnetic tape T.

Note that a straight line connecting the starting point and a point indicated by 0 on the upper edge of the magnetic tape T indicates a case where the reproducing operation is performed with the magnetic tape T stopped (hereinafter, “still reproduction”). ) Shows the rotation loci of the magnetic heads 13a and 13b drawn on the magnetic tape T.

As a specific example of this track pattern, a VHS (registered trademark) VTR, which is one of the typical VTR systems, is as follows.
In other words, in the most common VHS system VTR, 18
The magnetic tape T runs around a rotary drum having a diameter of 62 mm, which rotates at 00 rotations, in a state of being spirally wound over approximately 180 °. In the recording in the standard mode (hereinafter, referred to as “SP mode”), the magnetic tape is 33.3 per second.
The recording mark which is transported by 5 mm and drawn on the magnetic tape T by the magnetic head having a track width of 58 μm is a magnetic tape T
A video track angle of 5 ° 58'9.9 ”is formed with respect to the reference edge Te. In addition to the SP mode, the VHS type VTR has a magnetic tape of 11.12 mm / sec. And a triple mode (hereinafter referred to as "EP mode") in which recording is performed by a magnetic head having a track width of 19 μm. In the EP mode, by making the traveling speed and the track width of the magnetic tape T one third of that in the SP mode, recording can be performed three times as long on a magnetic tape of the same length. However, as described later, since the track width recorded on the magnetic tape is narrow, in the trick play, in order for the magnetic heads 13a and 13b to accurately trace each track, it is more difficult than in the SP mode. Is also difficult.

When the magnetic tape T is stopped, the rotation trajectory of the magnetic head drawn on the magnetic tape T is 5 ° 56'7.
4 ". For example, a straight line connecting the position of the upper edge of the magnetic tape T indicated by +7 in the SP mode in FIG. 3 and the starting point is the reference edge T of the magnetic tape T.
A straight line connecting the position of the upper edge of the magnetic tape T and the starting point indicated by -7 in the SP mode in FIG. 5 ° 42 ′ with respect to the reference edge Te of the magnetic tape T
25.7 ".

As apparent from the track pattern illustrated in FIG. 3, the track pattern recorded on the magnetic tape T in the SP mode and the magnetic tape T by the magnetic heads 13a and 13b during trick play. The rotation locus of the magnetic head depicted above crosses the rotation locus. Therefore, as shown in FIG. 2B, the signal level of the FM signal reproduced at the time of trick play greatly changes every time the magnetic heads 13a and 13b cross the recording trace, and the FM signal during one vertical scanning period is changed. Looking at the envelope, large undulations occur during one vertical scanning period. For this reason, as a reproduced image at the time of trick play, only a reproduced image of poor quality having a noise bar in the image can be obtained.

More recently, three recording marks having a recording mark width of 19 μm are simultaneously recorded in parallel on a magnetic tape T, and a recording mark pattern as shown in FIG. A VTR of a new form (hereinafter, referred to as “W-VHS system VTR”) has been commercialized which is capable of recording and reproducing so-called high-definition image information by being formed in T. This W-VHS VTR
In the above, two adjacent recording marks among the three recording marks formed in parallel on the magnetic tape T at the same time are used to record and reproduce video signals by two magnetic heads having azimuth angles opposite to each other. The remaining one recording track is used by another magnetic head for recording and reproducing an audio signal.

When the recorded magnetic tape T recorded by such a W-VHS VTR is run at a speed different from the speed at the time of recording and FF reproduction or FB reproduction is attempted, the movement locus of the magnetic head is shown in FIG. "Starting point" in (a)
Is indicated by a straight line connecting the position of the upper edge of the magnetic tape T indicated by the numeral +7 or -7 described above the upper edge of the magnetic tape T in the figure, for example. It will be. Therefore, two magnetic heads for video, each having a different azimuth angle, perform a reproducing operation across a plurality of recording traces formed on the magnetic tape T, so that the reproduced image is a noise bar. It will be full of things.

Further, although not described in detail, most recently proposed consumer digital VTRs compress and record the amount of video signal data using a high-efficiency encoding method, so that they can be used at the time of FF reproduction. When the rotating magnetic head performs a reproducing operation across the recording trace of the magnetic tape T as in the case of FB reproduction, an image cannot be reproduced at all depending on the arrangement state of the blocks of data arranged in a mosaic pattern. Occur.

In order to solve such a problem, the rotational locus of the magnetic head and the recording trace of the magnetic tape T may be made to coincide with each other. A method was proposed.

FIG. 5 is a perspective view showing the structure of a drum structure employed in a conventional magnetic recording / reproducing apparatus. FIG. 6 is a diagram showing track correction for correcting the upper and lower drums in the drum structure shown in FIG. FIG. 7 is a schematic diagram showing each rotation fulcrum when performing the lead correction for correcting the lead ring, and FIG. 7 is a diagram for explaining the operation of the drum assembly shown in FIG.

A drum structure 10A employed in the conventional magnetic recording / reproducing apparatus (VTR) shown in FIGS. 5 to 7 is disclosed in Japanese Patent Application Laid-Open No. Hei 6-318351. Please refer to the above publication if necessary.

In the drum structure 10A shown in FIGS. 5 and 6 (a) and 6 (b), a drum shaft 14 is press-fitted into the center of the lower drum 12, and a bearing 15a fitted to the drum shaft 14 is provided. , 15b, the upper drum 11 is coaxially supported. Then, the magnetic heads 13a, 1
Only the upper drum 11 mounted with 3b is rotatable about the drum shaft 14 by the drum motor 16. Further, a lead ring 17 having a spiral lead 17a for guiding the reference edge Te of the magnetic tape T is provided separately below the outer periphery of the lower drum 12. At this time, the magnetic tape T is applied to the upper drum 11 and the lower drum 12 by 180
゜ The wire is spirally wound over the above, as shown in FIG.
In the figure, the position indicated by 0 ° is the entrance side of the magnetic tape T, the position indicated by 90 ° is the center position of the winding range of the magnetic tape T, and the position indicated by 180 ° is the position of the magnetic tape T. Exit side. Further, the straight line L ₁ is a straight line perpendicular to the drum shaft 14 by connecting the axis O of the substantially central position and the drum shaft 14 of the winding range of the magnetic tape T to the circumferential surfaces of the upper and lower drums 11 and 12 described above, linear L ₂ is a straight line perpendicular to the straight line L ₁ passes through the axis O of the drum shaft 14. In the following description, the axis O of the drum shaft 14 will be described.
Was the origin angular position and disposed of the components by using a counter-clockwise angular coordinates the direction of the straight line L ₂ extending leftward and 0 ° direction from the axis O, the drum assembly 10
The cross-sectional direction of the cross-sectional view of A may be specified and described. For example, in the case of a cross-sectional view taken along the drum assembly 10A in a straight line L _2, the cross section is referred to as 0 ° -180 ° cross sectional view.

Then, the upper drum 11, the lower drum 12, and the lead ring 17 are placed on the drum base
When assembled as A, the lead ring 17 is supported rotating fulcrum member 19a, such as pins provided on the drum base 18 on 90 ° -270 ° line _{L 1,} with respect 19b rotatably, and, the drum base A compression spring 20 is narrowly mounted between the lead ring 18 and the lead ring 17, and a screw 24 screwed to the drum base 18 is in contact with the back surface of the bottom surface of the lead ring 17. The lower drum 12 is rotatably supported with respect to the inner periphery on the upper surface, such as pins provided on the 90 ° -270 ° line _{L 1} pivot fulcrum member 21a, 21b of the lead ring 17, and the lead A compression spring 22 is narrowly mounted between the ring 17 and the lower drum 12, and a screw 25 that passes through the drum base 18 and is screwed to the lead ring 17 is in contact with the back surface of the bottom surface of the lower drum 12. . Further, the lower end of the lower drum 12 penetrates the lead ring 17 and the drum base 18, and the lower surface of the drum base 18 is pressed by leaf springs 23 a and 23 b attached to the lower end of the lower drum 12. And, as described below, while being rotationally driven by a motor (not shown),
By pressing the bottom surface of the lower drum 12 with a screw 25 screwed to the lead ring 17, the upper and lower drums 11, 12 can be tilted in a predetermined direction with respect to the lead ring 17 a of the lead ring 17 integrally with the drum shaft 14. It has become. Further, the upper and lower drums 11, which are coaxially supported on the drum shaft 14 together with the lead ring 17, by being rotationally driven by a motor (not shown) and pushing the bottom surface of the lead ring 17 with a screw 24 screwed to the drum base 18. 12 is configured to be tiltable in a predetermined direction with respect to the drum base 18.

That is, in the normal reproduction mode as schematically shown in FIG. 7A, the upper and lower drums 1 supported coaxially on the drum shaft 14 with respect to the drum base 18.
Normal playback (not shown) of the bottom surface of the lower drum 11 and the bottom surface of the lead ring 17 is performed so that the bottom surfaces of the lower ring 11 and the lead ring 17 are maintained substantially parallel to the drum base 18 without being inclined with respect to the drum base 18. The screw 24 which is in contact with the state holding means and is screwed to the drum base 18 is retracted without contacting the bottom surface of the lead ring 17, while the screw 25 screwed to the lead ring 17 is also connected to the bottom surface of the lower drum 12. Shelters without abutment. Therefore, the virtual center axes of the drum shaft 14 and the lead ring 17 coincide with high accuracy, and these axes are perpendicular to the drum base 18. In this state, the magnetic tape T recorded in the standard mode is guided at its reference edge Te by the lead 17a of the lead ring 17 and runs at a predetermined speed (33.35 mm per second in the case of a VHS VTR) corresponding to the normal reproduction mode. Then, the magnetic head 13
The rotation trajectories a and 13b coincide with the track pattern recorded on the magnetic tape T, and a reproduced signal showing an envelope in a good state is obtained as illustrated in FIG. Here, the case where the normal reproduction mode is designated by the mode designation means (not shown) has been described. However, even when the so-called recording mode in which recording is performed on the magnetic tape T running at the standard speed is designated, the drum shaft 14 and the lead ring 17 are A similar operation is performed for adjusting the inclination angle of the virtual center axis.

Next, as schematically shown in FIG.
To change from the normal playback mode to the FF playback mode, a motor (not shown) is driven, and the screws 25 and 24 are simultaneously operated according to the double speed of fast-forward.
Lower drum 1 against lead ring 17 with screw 25
2, the lead ring 17 is pushed up against the drum base 18 by the screw 24.

That is, when the screw 25 screwed into the lead ring 17 is pushed out, the upper end pushes up the bottom surface of the lower drum 12. Thereby, the upper and lower drums 1 are integrated with the drum shaft 14 with respect to the leads 17a of the lead ring 17.
1 and 12 rotate clockwise around the rotation fulcrum members 21 a and 21 b against the urging force of the compression spring 22. This rotation changes the angle of the rotation trajectory surface of the magnetic heads 13a and 13b with respect to the lead 17a of the lead ring 17, and the rotation trajectory surface of the lead 17a and the magnetic heads 13a and 13b that substantially matches the desired fast-forward speed. A relative angle is obtained. (Hereinafter, the correction for changing the relative angle between the lead 17a and the rotation trajectory surfaces of the magnetic heads 13a and 13b is referred to as "track correction" or "primary correction" for convenience.) At this time, the combined screw 24 is simultaneously pushed upward in the drawing, so that the upper end pushes up the bottom surface of the lead ring 17. Thus, the upper and lower drums 11 and 12 supported coaxially with the drum shaft 14 together with the lead ring 17 with respect to the drum base 18 while maintaining the track correction state rotate against the urging force of the compression spring 20. It rotates clockwise around the fulcrum members 19a and 19b by a predetermined angle.

This is because the drum structure 1 accompanying the track correction
When the magnetic tape T is pulled in the direction of the rotation by the rotation of the magnetic tape T, the reference edge Te of the magnetic tape T with respect to the entrance side of the magnetic tape T with respect to the drum structure 10A is set to the lead ring 17.
The lead ring 17 is rotated to adjust the lead 17a to the reference edge Te of the magnetic tape T because the reference edge Te tends to be pressed against the lead 17a on the exit side. (Less than,
The correction for rotating the lead ring 17 to adjust the lead 17a to the displacement of the reference edge Te of the magnetic tape T accompanying the track correction is called "lead correction" or "secondary correction" for convenience. In other words, here, even when lead correction is performed,
Lead 17 and magnetic head 13 adapted to rapid traverse speed
It is needless to say that the relative angles of a and 13b with respect to the rotation locus plane are maintained.

Therefore, the track correction (primary correction) by the screw 25 screwed to the lead ring 17 and the lead correction (primary correction) by the screw 24 screwed to the drum base 18 are simultaneously performed, and the read ring Upper and lower drum 1 coaxially supported on drum shaft 14 together with 17
1 and 12 rotate clockwise relative to the drum base 18 by the sum of the track correction and the read correction. (Hereinafter, the correction obtained by adding the track correction and the read correction will be referred to as “whole drum correction” for convenience.) Then, the reference edge Te of the magnetic tape T is obtained by the track correction.
Is separated from the lead 17a of the lead ring 17 by this lead correction, the reference edge Te of the magnetic tape T is stably guided by the lead 17a over the entire winding range around the drum structure 10A. When the magnetic tape T runs at the double speed of the rapid traverse, the magnetic heads 13a, 13
The rotation trajectory b corresponds to the track pattern recorded on the magnetic tape T, and a reproduced signal indicating the envelope in a good state is obtained as illustrated in FIG. 2A.

Next, as schematically shown in FIG.
For example, to change from the normal playback mode to the FB playback mode, a motor (not shown) is rotated in the opposite direction to the above-described FF playback mode, and the screws 25 and 24 are moved to the bottom surface of the lower drum 12. Lead ring 17
When the screw 25 screwed to the lead ring 17 is retracted while being in contact with the bottom surface of the lead ring 17, the upper and lower drums 11, 12 are integrated with the drum shaft 14 with respect to the lead 17 a of the lead ring 17, and the compression spring 22 By the biasing force described above, the track correction that rotates counterclockwise around the rotation fulcrum members 21a and 21b is performed. On the other hand, drum base 1
The upper and lower drums 11 and 12 coaxially supported on the drum shaft 14 together with the lead ring 17 with respect to the drum base 18 while maintaining the track correction state by the retreat of the screw 24 screwed into the screw 8. Due to the force, the lead correction that rotates counterclockwise around the rotation fulcrum members 19a and 19b is performed. The upper and lower drums 11 and 1 coaxially supported on the drum shaft 14 together with the lead ring 17.
2 rotates counterclockwise with respect to the drum base 18 by the sum of the track correction amount and the read correction amount, and the entire drum is corrected.

[0030]

The conventional VT
In R1, the drum shaft 1 is used during fast forward playback or fast reverse playback.
Since the upper and lower drums 11 and 12 coaxially supported by 4 and the read ring 17 are inclined in a predetermined direction, a reproduced image without a noise bar can be obtained in fast forward reproduction and fast reverse reproduction. the pivot point is the drum base 18 on at 90 ° -270 ° line _{L 1} on the provided pivoting fulcrum member 19a, a 19b, the rotation fulcrum of the lower drum 12 on the inner peripheral upper surface of the lead ring 17 90 ゜ -2
Rotation fulcrum member 21a provided on the 70 ° line L _1, since it is 21b, the upper and lower drums 11 and 12 at the time of normal playback that coaxially supported on the drum shaft 14 as previously described,
A normal reproduction state holding means (not shown) is required to hold the lead ring 17 in a state substantially parallel to the drum base 18 without inclining the lead ring 17 with respect to the drum base 18. The drum 12 and the lead ring 17 must be configured so as to be able to freely contact and separate from each other with high precision, so that the structure of the normal reproduction state holding means becomes complicated.

The rotation fulcrum members 19a and 19b provided on the drum base 18 and the rotation fulcrum members 21a and 21b provided on the inner peripheral upper surface of the lead ring 17 are 90 ° -2.
Since only located on 70 ° lines L _1, Toka wear resistance of the pivot fulcrum member, together with a weak structure form with respect Toka impact resistance against an impact from the outside, lead ring 17
Since the upper and lower surfaces must be processed, there still remains a problem that the thickness between the upper and lower surfaces of the lead ring 17 tends to vary.

In the FF playback mode and the FB playback mode shown in FIGS. 7B and 7C, the screw 24 screwed to the drum base 18 is naturally not tilted because it is supported by the drum base 18. However, on the other hand, the screw 25 screwed to the lead ring 17 is inclined with respect to the drum base 18 as shown in FIG. At the lower end, the inclination width is enlarged. At this time, gears (not shown) are integrally provided at the lower ends of the screws 24 and 25, respectively.
Although it is engaged with a drive gear (not shown) for operating the screw, it is difficult to maintain the meshing state of the screw 25 with the drive gear, which is inclined with the inclination of the lead ring 17, in a favorable state. Room is left.

Further, since the screw 24 and the screw 25 are simultaneously operated by the driving gear (not shown),
When meshing these screws 24, 25 with the driving gear, it is necessary to adjust the meshing position (gear phase) between the screws 24, 25 and the driving gear, respectively. Is desired.

Further, a screw 24 screwed to the drum base 18 and a screw 25 screwed to the lead ring 17
Although they move up and down linearly by rotating, there is a problem that the movable range is not regulated and there is a possibility that they may rotate extra.

[0035]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a first invention is to provide a rotatable upper drum mounted with a rotating magnetic head and a lower drum on a drum shaft. A lead ring, which is coaxially supported and forms a lead for guiding a reference edge of the magnetic tape, is coaxially fitted with the lower drum, and the upper and lower coaxially supported by the lead ring and the drum shaft. Support the drum on the drum base,
A recording / reproducing operation in which an inclined recording mark at a predetermined angle with respect to a reference edge of the magnetic tape is formed on the magnetic tape wound around a part of the peripheral surface of the upper and lower drums using the rotating magnetic head When performing the above, the lead of the lead ring is coaxially supported on the drum shaft so that the recording mark formed on the magnetic tape and the rotation locus surface of the rotary magnetic head coincide with each other. A primary correction in which the upper and lower drums are inclined in opposite directions at the entrance side and the exit side of the winding of the magnetic tape around the upper and lower drums according to the traveling speed of the magnetic tape; The upper and lower drums coaxially supported by the lead ring and the drum shaft with respect to the drum base so as to coincide with the reference edge of the tape at the entrance side and the exit side of the magnetic tape winding. Secondary tilting in opposite directions In a magnetic recording / reproducing apparatus provided with an angle correcting means having a plurality of screws for performing positive and negative, respectively, the plurality of screws are screwed to a first screw screwed to the drum base and to the lead ring. And a second screw operated by a drive gear, and the second screw is connected to the drive gear via a coupling gear.

According to a second aspect of the present invention, in the magnetic recording / reproducing apparatus of the first aspect, a gear portion is provided integrally with the second screw, and external teeth of the gear portion are connected to internal teeth of the coupling gear. A magnetic recording / reproducing apparatus characterized in that a screw interlocking gear that meshes in a loosely fitted state and rotates integrally with the coupling gear meshes with the drive gear.

According to a third aspect of the present invention, there is provided a lead for supporting a rotatable upper drum and a lower drum coaxially with a drum shaft, and for guiding a reference edge of a magnetic tape. The formed lead ring is coaxially fitted with the lower drum, and the lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base. When a recording / reproducing operation is performed on the magnetic tape in a state wound around the magnetic tape by forming an inclined recording mark at a predetermined angle with respect to a reference edge of the magnetic tape using the rotary magnetic head, The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the formed recording traces and the rotational trajectory surface of the rotary magnetic head coincide with each other. Depending on the traveling speed of the Primary correction in which the magnetic tape is wound around the magnetic tape on the entrance side and the exit side in the opposite direction, and the drum base is adjusted so that the lead of the lead ring coincides with the reference edge of the magnetic tape. A plurality of secondary corrections for inclining the upper and lower drums coaxially supported by the lead ring and the drum shaft in directions opposite to each other at the entrance side and the exit side of the magnetic tape winding. In the magnetic recording / reproducing apparatus provided with an angle correcting means having a screw, the plurality of screws are a first screw side screwed to the drum base and a second screw side screwed to the lead ring. The first and second gear portions provided on the first screw portion are meshed with a drive gear, and the first gear portion provided on the first screw side is the drum base and a support base supported by the drum base. Rotated between And a distance between the drum base and the support is set to a value obtained by adding an operating range of the first screw and a distance between both ends of the first gear portion. Device.

According to a fourth aspect of the present invention, there is provided a lead for supporting a rotatable upper drum and a lower drum coaxially with a rotary magnetic head on a drum shaft and guiding a reference edge of a magnetic tape. The formed lead ring is coaxially fitted with the lower drum, and the lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base. When a recording / reproducing operation is performed on the magnetic tape in a state wound around the magnetic tape by forming an inclined recording mark at a predetermined angle with respect to a reference edge of the magnetic tape using the rotary magnetic head, The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the formed recording traces and the rotational trajectory surface of the rotary magnetic head coincide with each other. Depending on the traveling speed of the Primary correction in which the magnetic tape is wound around the magnetic tape on the entrance side and the exit side in the opposite direction, and the drum base is adjusted so that the lead of the lead ring coincides with the reference edge of the magnetic tape. A plurality of secondary corrections for inclining the upper and lower drums coaxially supported by the lead ring and the drum shaft in directions opposite to each other at the entrance side and the exit side of the magnetic tape winding. In the magnetic recording / reproducing apparatus provided with an angle correcting means having a screw, the plurality of screws are a first screw side screwed to the drum base and a second screw side screwed to the lead ring. The first and second gear portions provided respectively are engaged with the drive gear, and the drive gear is displaced in the axial direction of the drive gear when the first and second screws are adjusted, so that the drive gear First and second gear A magnetic recording and reproducing apparatus characterized by being configured so as to release the engagement of the.

According to a fifth aspect of the present invention, there is provided the magnetic recording / reproducing apparatus according to the fourth aspect, wherein a position where the first and second gear portions mesh with the drive gear, and a position where the first and second gear portions are meshed. A magnetic recording / reproducing apparatus, wherein the drive gear is configured to be displaceable in the axial direction of the drive gear by a displacement member that is displaced between a portion and a position at which the engagement between the drive gear and the drive gear is released.

According to a sixth aspect of the present invention, there is provided a lead for supporting a rotatable upper drum on which a rotary magnetic head is mounted and a lower drum coaxially with a drum shaft and guiding a reference edge of a magnetic tape. The formed lead ring is coaxially fitted with the lower drum, and the lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base. When a recording / reproducing operation is performed on the magnetic tape in a state wound around the magnetic tape by forming an inclined recording mark at a predetermined angle with respect to a reference edge of the magnetic tape using the rotary magnetic head, The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the recording traces formed and the rotation locus surfaces of the rotary magnetic head coincide with each other. Depending on the traveling speed of the Primary correction in which the magnetic tape is wound around the magnetic tape on the entrance side and the exit side in the opposite direction, and the drum base is adjusted so that the lead of the lead ring coincides with the reference edge of the magnetic tape. Angle correction means for performing secondary correction for tilting the upper and lower drums coaxially supported by the lead ring and the drum shaft in directions opposite to each other at the entrance side and the exit side of the magnetic tape winding. In the magnetic recording / reproducing apparatus provided, the angle correcting means includes: first and second pivots provided on the drum base; first and second pivots provided on the lead ring; A drive that meshes with first and second gear portions respectively provided on a first screw side screwed to the base and a second screw side screwed to the lead ring, and is rotated by being reduced in speed by the motor. Gear and the drive gear A reset rotator that forms a reset detector that resets a pulse counter that counts the number of rotation pulses of the motor while rotating approximately ± 180 °, and a detection element that detects the reset detector of the reset rotator. The lead ring abuts on first and second pivot points provided on the drum base, and the first and second pins provided on the lead ring
When the lower drum abuts on the rotation fulcrum and the first and second screws are separated from the lower drum, the reset element of the reset rotary body is detected by the detection element when the first and second screws are separated from the lower drum. A magnetic recording / reproducing apparatus characterized in that:

According to a seventh aspect of the present invention, in the magnetic recording / reproducing apparatus according to the sixth aspect, the first and second gear portions are engaged with the drive gear when the first and second screws are operated. When adjusting the first and second screws, the first and second screws are adjusted.
The drive gear is configured to be displaceable in the axial direction of the drive gear so that the second gear portion is disengaged from the drive gear, and the resetting rotation is performed when the first and second screws are adjusted. A magnetic recording / reproducing apparatus characterized in that a body is temporarily fixed at a predetermined position.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a magnetic recording / reproducing apparatus according to the present invention will be described below in detail with reference to FIGS.
For convenience of description, the same components as those described above will be denoted by the same reference numerals.

FIG. 8 is a perspective view showing the structure of a drum structure applied to the magnetic recording / reproducing apparatus according to the present invention, and FIG. 9 is a longitudinal sectional view showing the structure of the drum structure applied to the magnetic recording / reproducing apparatus. 10 (a) and 10 (b) are a top view and a GG sectional view of the top surface of the drum structure in the magnetic recording / reproducing apparatus taken along a line GG, and FIGS. FIG. 12A and FIG. 12B are top and bottom views of the drum structure in the magnetic recording / reproducing apparatus taken along the XOYZ line, and FIG. FIG. 13 illustrates a top view of a drum structure and a cross-sectional view taken along line EE of the drum structure in the reproducing apparatus, and FIG. 13 illustrates a structure in which a screw screwed to a lead ring is connected by a coupling gear in the drum structure. FIG.

The structure of the drum structure 10B applied to the magnetic recording / reproducing apparatus according to the present invention shown in FIGS.
A drum shaft 14 is press-fitted into the center of the lower drum 12, and bearings 15 a, 1 fitted to the drum shaft 14 are fitted.
The upper drum 11 is coaxially supported via 5b.
Tape sliding surfaces 11a, 12a for winding and guiding the magnetic tape T are formed on the outer circumferences of the upper and lower drums 11, 12 to have substantially the same diameter. The lower drum 12 has a small-diameter portion 12b having a smaller diameter than the tape sliding contact surface 12a.
A small-diameter portion 12d, which is spirally formed below the bottom portion 2a and smaller in diameter than the small-diameter portion 12b below the center of the bottom surface portion 12c, is formed so as to project toward a drum base 18 described later. Only the upper drum 11 having the magnetic heads 13a and 13b is mounted on the drum motor 16 around the drum shaft 14.
It is rotatable by the driving force of. At this time, the drum motor 16 is configured by combining a stator 16 a fixed to the upper end of the drum shaft 14 and a rotor 16 b that rotates integrally with the upper drum 11. Further, the rotary transformer 26a attached to the upper drum 11 and the lower drum 12
Between the magnetic transformer 1 and the rotary transformer 26b attached to the
The signals 3a and 13b are transmitted and received.

Further, a spiral lead 17a for guiding the reference edge Te of the magnetic tape T is provided below the outer periphery of the lower drum 12.
Is formed as a separate body. The lead ring 17 is loosely fitted in a state of approaching the outer peripheral surface of a spirally formed small-diameter portion 12b below the lower drum 12, and an annular portion 17b having a spiral lead 17a at the upper end and a bottom surface. This is roughly constituted by a portion 17c. A through hole is formed at the center of the bottom surface portion 17c of the lead ring 17, and a knife edge portion 17d to be coaxially fitted with the lower small diameter portion 12d of the lower drum 12 is formed in the inner peripheral portion of the through hole. Are formed. Therefore, the upper and lower drums 11 and 12 supported coaxially on the drum shaft 14
The lead ring 17 can be fitted coaxially on the bottom surface 17c.

Then, the upper drum 11, the lower drum 12, and the lead ring 17 are placed on the drum base 18 by the drum assembly 10
Before assembling as B, a more specific configuration will be described below with reference to FIGS.

Firstly, FIG. 10 (a), the as shown (b), the the outer periphery of the bottom portion 12c of the lower drum 12, 0 ° -180 ° line _{L 2} on at 90 ° -270 ° line _{L 1} The positioning pins 27a and 27b having good wear resistance are fixed symmetrically, and the lower ends of the positioning pins 27a and 27b correspond to these, and the elliptical holes 17c ₁ and the round holes 17c formed in the bottom surface portion 17c of the lead ring 17 corresponding thereto. ₂ so as to face the inside. At this time, the positioning of the 0 one positioning pin 27a of DEG side loosely fitting the oval hole 17c ₁ at 0 ° -180 ° direction, the lower drum 12 and the lead ring 17 direction is restricted in position perpendicular thereto doing. The positioning pin 27a of the 180 ° side is loosely fitted in the round hole 17c _2. Further, corresponding to the lower ends of the positioning pins 27a and 27b, the upper ends of first screws (hereinafter referred to as screws) 24a and 24b screwed to the drum base 18 are freely movable.

The screws 24a and 24b screwed to the drum base 18 press the lower drum 12 without contacting the lead ring 17,
These screws 24a and 24b are used for lead correction (secondary correction) by the screw 24 described in the conventional example.
Unlike the operation, a function for performing the entire drum correction is provided. That is, as described later, in the FF reproduction mode, the upper end of the 0 ° screw 24a is positioned at the upper end of the 0 ° positioning screw 2a.
By pushing up 7 a, 0
The upper and lower drums 1 coaxially supported on the drum shaft 14 together with the lead ring 17 by pushing up the bottom surface portion 12 c on the ゜ side.
15 and 21 with respect to the drum base 18.
In the FF reproduction mode, the entire drum is corrected by rotating the drum in the clockwise direction by the entire drum correction inclination angle θ shown in FIG.
By pushing up the 180 ° positioning pin 27b at the upper end of the 180 ° screw 24b in the B playback mode, the entire drum is corrected in the FB playback mode by turning counterclockwise in the opposite direction. ing. still,
In the FF playback mode and the FB playback mode, even if the lower drum 12 is rotated by the screws 24a and 24b screwed to the drum base 18, the screws 24a and 24b do not tilt, and thus are integrated with the lower ends of the screws 24a and 24b. Are directly meshed with two-stage gears 60 and 61 provided in a driving means 50 (FIG. 14) described later.

Next, FIG. 11 (a), the as shown (b), the the outer periphery of the bottom portion 12c of the lower drum 12, 90 ° -270 ° in the illustrated above 0 ° -180 ° line _{L 2} Line L
Good pin 28a of abrasion resistance ₁ symmetrically, (28b) is fixed, a pin 28a, lower side escape hole _17c 3 bored in the bottom surface portion 17c of the lead ring 17 (28b), (1
7c ₄ ). Furthermore, the upper ends of second screws (hereinafter referred to as screws) 25a and (25b) screwed to the bottom surface portion 17c of the lead ring 17 are freely connected to and separated from the lower ends of the pins 28a and (28b). , The lower ends of the screws 25a, 25b face the stepped holes 18a, 18b of the drum base 18 formed correspondingly.

Here, as shown in FIGS. 13 (a) to 13 (c), among the screws 25a and (25b) screwed to the bottom 17c of the lead ring 17, the screw 2
The 5a side will be described. Since the screw 25b has the same structure, the description is omitted. When the screw 25a extends to the back side of the drum base 18, when the screw 25a is operated as described in the related art,
With the inclination of the lead ring 17, the extended portion of the screw 25a is also inclined, and this extended portion is the drum base 1
8 is enlarged on the back side.

Therefore, as shown in FIG. 13A, the upper large-diameter hole 1 of the stepped hole 18a formed in the drum base 18 is formed.
8a ₁ , the coupling gear 41 press-fitted into the upper end of the shaft 40 is inserted, and the shaft 40 is inserted into the stepped hole 1.
Combined shaft fit in the lower small-diameter hole 18a ₂ of 8a and the drum base 1
8, a screw interlocking gear 42 is fixed to the lower end of the extended shaft 40. At this time, the screw interlocking gear 42 supported on the drum base 18 via the shaft 40 meshes with a small-diameter gear portion 60b of a two-stage gear 60 provided in a driving means 50 (FIG. 14) described later, and is rotatable. I have. A gear portion 25a integrally provided below the screw 25a screwed to the lead ring 17
₁ is loosely engaged with the coupling gear 41 inserted into the stepped hole 18a of the drum base 18.

[0052] Here, as shown in FIG. 13 (b), on the inner periphery of the coupling gear 41 and the internal teeth are formed, the gear portion 25a ₁ of the inner tooth screw 25a of the coupling gear 41 external teeth and module and number of teeth are formed on the same, and, since the gap between them is transition between the inner teeth and outer teeth are formed, the external teeth of the gear portion 25a ₁ of the screw 25a is cup It meshes with the internal teeth of the ring gear 41 in a loosely fitted state. And the screw interlocking gear 42
When the integral coupling gear 41 rotates via the shaft 40 and the shaft 40, the rotation of the coupling gear 41 causes the screw 25 engaged with the coupling gear 41 in a loosely fitted state.
It is transmitted to the gear portion 25a ₁ of a. Then, the gear portion 25a ₁ of the screw 25a rotates together with the coupling gear 41, the lead ring screw 25a 1
With the rotation by screwing to 7, freely separable to a pin 28a of the upper end of the screw 25a while vertically moved inside the inner teeth has been pressed into the bottom portion 12c of the lower drum 12 of the gear portion 25a ₁ is the coupling gear 41 It has become.

Therefore, as shown in FIG. 13C, when the screw 25a screwed to the lead ring 17 is operated, the screw 25a
Is tilted with respect to the drum base 18, the screw 25
without causing also trouble in any way between them by meshing relationship in the loosely fitted state between the gear portion 25a ₁ and the coupling gear 41 of a, and a screw engaging gears 42 for actuating the screw 25a is, the drum base 18 The screw interlocking gear 4
2 can accurately and reliably mesh with the small-diameter gear portion 60b of the two-stage gear 60 provided in the driving means 50 (FIG. 14).

Referring back to FIGS. 11A and 11B, the screws 25a and 25b screwed to the lead ring 17 are
The lower drum 12 is pressed, and has a function of performing track correction (primary correction) as described in the conventional example. That is, as described later, the upper end of the screw 25a on the 0 ° side is connected to the pin 28 on the 0 ° side in the FF playback mode.
When brought into contact with a, 15 a bottom portion 17c of the 0 ° side of the lead ring 17 relative to the lower drum 12, in the direction to push down by the track correction angle of inclination theta ₁ shown in FIG. 21 (a counterclockwise direction) By rotating and performing the track correction in the FF playback mode, the 180 ° screw 25b is brought into contact with the 180 ° pin 28b in the FB playback mode, so that the rotation of the lead ring 17 is reversed. The track correction in the FB playback mode is performed by rotating the 180 ° side bottom portion 17c in a direction (clockwise) to push down the lower drum 12.

Next, the operation of the lead correction (secondary correction) in the embodiment is as follows. With respect to the lower drum 12 rotated by the entire drum correction inclination angle θ from the above, the lead ring 17 is moved from the entire drum correction inclination angle θ. since the rotation to the tilt direction opposite to the direction of the smaller angular track correction angle of inclination theta ₁ only the lower drum 12, the lead correction angle of inclination theta ₂ minutes obtained by subtracting the track correction angle of inclination theta ₁ of the entire drum corrected tilt angle theta However, the read ring 17 rotates clockwise with respect to the drum base 18, and this operation is read correction in the FF reproduction mode. Of course, in the lead correction in the FB playback mode, the lead ring 17
Rotates counterclockwise in the opposite direction.

From the above, the screws (first screws) 24a and 24b are used to connect the upper and lower drums 11 and 12 coaxially supported on the drum shaft 14 together with the lead ring 17 in the FF reproduction mode and the FB reproduction mode. Base 1
8 is a drum-wide correction means for inclining the magnetic tape T on the upper and lower drums 11 and 12 in opposite directions on the entrance side and the exit side in accordance with the running speed of the magnetic tape T.

A screw (second screw) 2
Reference numerals 5a and 25b denote recording marks formed on the magnetic tape T and the magnetic head 1 in the FF reproduction mode and the FB reproduction mode.
By inclining the lead ring 17 with respect to the lower drum 12 so as to push down on the lower drum 12 so that the rotational trajectory surfaces of 3a and 13b coincide with each other, the directions of entry and exit of the magnetic tape winding are opposite to each other. Track correcting means for displacing the track.

The screws 24a and 24b for correcting the entire drum and the screws 25 for correcting the track
a and 25b in cooperation with the drum base 18 so that the lead 17a of the lead ring 17 coincides with the reference edge Te of the magnetic tape T in the FF reproduction mode and the FB reproduction mode. The upper and lower drums 11 and 12 coaxially supported by the drum shaft 14 are inclined in opposite directions at the entrance side and the exit side of the magnetic tape winding.

Therefore, the screw (first correction) for performing (the whole drum correction)-(track correction) = (lead correction)
The screw (second screw) 24a, 24b and the screw (second screw) 25a, 25b cooperate with each other to serve as angle correction means.

In the vicinity of the screws 25a and 25b screwed to the bottom surface 17c of the lead ring 17, compression springs 29a and 29b are narrowly mounted between the back surface of the bottom surface 17c of the lead ring 17 and the drum base 18. The compression springs 29a and 29b press the lead ring 17 toward the lower drum 12 with a weak spring force.

[0061] In addition, at 90 ° -270 ° line _{L 1} 0 ° -1
80 ° line _{L 2} positioned symmetrically pins 30a, 30b and the outer periphery of the bottom portion 12c of the lower drum 12, and near the outer periphery of the bottom portion 17c of the lead ring 17 is provided between the drum base 18, these Positioning pins 30a, 30b
Position the lower drum 12 and the drum base 18.

FIGS. 11A and 11B and FIG.
(A), as shown (b), the on a rear surface of the drum base 18, 0 ° to 90 ° -270 ° line _{L 1} -180 ° line L
₂ are symmetrically formed with stepped holes 18c and (18d). In these stepped holes 18c and (18d), flanged screws 32a and (32b) fitted with compression springs 31a and (31b) are provided. Are inserted from below, and the upper ends of the flanged screws 32a and (32b) are
7 and screwed into the lower drum 12. At this time, the compression springs 31a and 31b are set stronger than the compression springs 29a and 29b described above. Then, the lower drum 12 is moved toward the drum base 18 by the strong urging force of the compression springs 31a and 31b that are narrowly mounted between the flanges of the flanged screws 32a and 32b and the stepped holes 18c and 18d. Has been energized.

Next, when the upper and lower drums 11 and 12 coaxially supported by the drum shaft 14 and the lead ring 17 are rotated clockwise or counterclockwise with respect to the drum base 18, the lower drum 12 is moved to the lower drum 12. Regarding the pivot point, FIG.
This will be described with reference to (a) and (b).

[0064] In the figure, the outer periphery of the upper surface side of the drum base 18, 90 ° -270 ° line _{L 1} and 0 ° -1
The first pivot point _18e 80 ° line _{L 2} respectively symmetric 1, 18
e ₂ and the second rotation fulcrums 18f ₁ , 18f ₂ are formed to protrude toward the lower drum 12 while maintaining the height accuracy. In other words, the first rotation fulcrum 18e on the drum base 18 is formed. ₁ , 18e ₂ and second rotation fulcrums 18f ₁ , 18f
₂ is provided on the left and right sides via the drum shaft 14. In addition, the first rotation fulcrum 18
e ₁ , 18e ₂ and second pivots 18f ₁ , 18f
_2, a 90 ° -270 ° line _{L 1} in the symmetrical 90 ° -2
Although substantially located on parallel ridge 70 ° line L _1, it may be located in the vicinity of the substantially parallel ridge 90 ° -270 ° line L ₁ in some cases. Further, the first rotation fulcrum 18e ₁ , 18e ₂ and the second rotation fulcrum 18 on the drum base 18
f ₁ and 18f ₂ correspond to the lead ring 17
Has become freely contact and separation on the rear surface of the bottom portion 12c of the lower drum 12 to escape hole 17c ₅ ~17c ₈ bored in the bottom surface portion 17c of the through, the normal playback mode as will be described below first of 0 ° side One rotation fulcrum 18e ₁ , 18e ₂ and 180
The second rotation fulcrums 18f ₁ and 18f ₂ on the ゜ side are
Abuts on the bottom portion 12c of the
The second rotation fulcrums 18f ₁ and 18f ₂ on the ゜ side are
Of these, the first rotation fulcrums 18e ₁ and 18e ₂ on the 0 ° side are in contact with the 180 ° side bottom surface portion 12c during the FB playback mode.
Abuts on the bottom surface portion 12c on the 0 ° side of the lower drum 12.

Next, at the inner periphery of the lead ring 17,
The outer periphery of the upper surface of the 7c, first pivot point 90 ° -270 ° line _{L 1} and 0 ° -180 ° line _{L 2} respectively symmetrical 17
e _1, and 17e _2, formed to project toward the lower drum 12 side to maintain ₂ and the second rotation fulcrum _17f 1, 17f is the height precision, in other words, 1st on lead ring 17 of The movement supporting points 17e ₁ and 17e ₂ and the second rotation supporting point 17f
_1, 17f ₂ leftward through the drum shaft 14 and is provided to the right. Further, the first rotation fulcrums 17e ₁ and 17e ₂ and the second rotation fulcrums 17f ₁ and 17f ₁ on the lead ring 17 are also provided.
f ₂ is also 90 ° and symmetrically of 90 ° -270 ° line _{L 1} -
Although positioned substantially parallel to the ridge 270 ° line L _1, in some cases may be located in the vicinity of the substantially parallel ridge 90 ° -270 ° line L _1, and the first pivot Fulcrum 17e
_1, 17e ₂ and the second pivot point _17f 1, 17f ₂ is first pivot point _18e on the drum base 18 as described above 1, 1
8e ₂ and the second rotation fulcrums 18f ₁ , 18f ₂ . Further, the first rotation fulcrums 17e ₁ and 17e ₂ and the second rotation fulcrums 17f ₁ and 17f on the lead ring 17 are formed.
Numeral ₂ is freely movable toward and away from the back surface of the bottom surface portion 12c of the lower drum 12. As will be described later, in the normal reproduction mode, the first rotation fulcrums 17e ₁ and 17e ₂ on the 0 ° side and the second rotation fulcrums on the 180 ° side. The rotation fulcrums 17f ₁ and 17f ₂ abut on the bottom surface 12c of the lower drum 12, and the second rotation fulcrums 17f ₁ and 17f ₂ on the 180 ° side are the bottom surface on the 180 ° side of the lower drum 12 in the FF playback mode. The first rotation fulcrums 17e ₁ and 17e ₂ on the 0 ° side are in contact with the 0 ° bottom surface portion 12c of the lower drum 12 in the FB playback mode. At this time, the back side of the bottom surface portion 17c of the lead ring 17 does not need dimensional accuracy, and only the inner peripheral upper surface side needs to be processed with high dimensional accuracy. In the embodiment, the first rotation fulcrum 17 e ₁ , 1
7e ₂ and the second pivot point _17f 1, 17f ₂ While described is provided, not limited to this, the first pivot point and second pivot point of the corresponding to the rear surface of the bottom portion 12c of the lower drum 12 In other words, it is only necessary to provide the corresponding first pivot fulcrum and second pivot fulcrum between the lead ring 17 and the lower drum 12 via the drum shaft 14, respectively. is there.

Next, a driving means 50 for simultaneously rotating the screws 24a and 24b for rotating the lower drum 12 and the screws 25a and 25b for rotating the lead ring 17 will be described with reference to FIGS. FIG.
This will be briefly described with reference to FIG. FIG. 14 is a bottom view showing the driving means attached to the lower surface of the drum structure in the magnetic recording / reproducing apparatus according to the present invention. FIG.
FIG. 16 shows the inclination angle characteristics of the lead correction. FIG. 16 shows the driving means for adjusting the meshing position of the gears when the screw screwed to the drum base and the screw screwed to the lead ring are meshed with the drive gear. FIG. 17 is a view for explaining a structure to be performed, FIG. 17 is a view for explaining a modification of the displacement member shown in FIG. 16 in the driving means, and FIG. FIG. 19 is a view for explaining the structure of the drive gear, and FIG. 19 is a view for explaining the positioning of the reset gear in the driving means. In the following description, the screw 25a screwed to the lead ring 17 is interlocked with the screw interlocking gear 42 via the coupling gear 41 as described above with reference to FIG. Is equivalent to the screw interlocking gear 42, and is illustrated and described as a screw 25a for easy understanding of the description.

In FIG. 14, a support table 51 for mounting the driving means 50 is supported on the back side of the drum base 18. Here, the rotation of the first pulley 53 fixed to the shaft of the motor 52 on the support table 51 is transmitted to the worm 57 of the shaft 56 to which the second pulley 55 is fixed via the belt 54, and meshes with the worm 57. First helical gear 58
And the second helical gear 59 meshed with the first helical gear 58
Is transmitted to each. Here, the rotation direction of the first helical gear 58 and the rotation direction of the second helical gear 59 are reversed. The first helical gear 58 is a large-diameter gear portion 60a of a drive gear (hereinafter referred to as a two-stage gear) 60 in the gear train.
Screw meshed with the gear portion 24a ₁ and the second-stage small-diameter gear portion 60b of the gear 60 of the screw 24a which is meshed with the 25
rotate the gear portion 25a ₁ of a. Simultaneous with this, the second helical gear 59, the driving gear in the gear train (hereinafter, the second gear hereinafter) 61 small-diameter gear of the gear portion 24b ₁ and the second gear 61 of the screw 24b which meshes with the large diameter gear portion 61a of the gear portion 25b ₁ of the screw 24a of the screw 25b which meshes with the part 61b, is rotated in a direction that reverses the rotation direction of 25a. In addition, 2 connected to the second helical gear 59
The step gear 61 further rotates a reset rotating body (hereinafter, referred to as a reset gear) 62 via a gear train. The rotation of the reset gear 62 is reduced so as to rotate within a range of approximately ± 180 °.

At this time, the screws 24a and 24b for performing the correction of the entire drum are provided with two rotations with respect to the rotation of the motor 52.
Due to the engagement with the large-diameter gear portions 60a, 61a of the step gears 60, 61, the inclination characteristics as shown in FIG. On the other hand, a screw 25a for performing track correction, 25b, such that the lead correction angle of inclination theta ₂ obtained by subtracting the track correction angle of inclination theta ₁ of the entire drum correction inclination angle theta is obtained, with respect to the rotation of the motor 52 2 Small-diameter gear portions 60b, 61 of the step gears 60, 61
Due to the engagement with b, the inclination characteristic as shown in FIG. 15 follows the small lead correction inclination angle characteristic. FIG.
Both the drum overall correction tilt angle characteristic and the lead correction tilt angle characteristic as shown in FIG. The above-mentioned dead zone means that the screws 24a and 24b screwed to the drum base 18 are separated from the lower drum 12, the screws 25a and 25b screwed to the lead ring 17 are also separated from the lower drum 12, and One rotation fulcrum 18e ₁ , 18e ₂ and second rotation fulcrum 18f ₁ , 18f ₂ and first rotation fulcrum 17e ₁ , 17e ₂ and second rotation fulcrum 1 on lead ring 17
7f ₁ and 17f ₂ correspond to a later-described normal reproduction mode state in which the bottom surface 12c of the lower drum 12 is in contact with the back surface.

The second pulley 55 has a plurality (for example, 3
And a fan-shaped motor rotation pulse detection unit (hereinafter referred to as a light shielding plate) 55a for detecting the number of rotation pulses when the motor 52 rotates (photonics sensor)
Detected by the pulse counter PC via 63 to detect whether the upper and lower drums 11, 12 and the lead ring 17 coaxially supported on the drum shaft 14 have tilted to the target angle. At this time, the pulse counter PC is connected to the drum structure 1
0B. In the embodiment, the light shielding plate 55a of the second pulley 55 and the photonics sensor 63 are motor rotation pulse output means. However, the present invention is not limited to this.

The reset gear 62 has a semicircular fan-shaped reset detector (hereinafter referred to as a light shielding plate) 62 of approximately 180 °.
The edge of the light shielding plate 62a is detected by a detecting element (hereinafter, referred to as a photonics sensor) 64 in a normal reproduction mode described later, and the pulse counter PC is reset by this signal.

Next, the screws 24a, 25a
FIGS. 16 (a) to 16 (d) and FIGS. 17 (a) to (d) show a structure for adjusting the meshing position of the gears when the gear portions 24a ₁ and 25a ₁ are meshed with the two-stage gear 60. This will be described with reference to FIG. The gear 25a of the screw 25a
₁ is described as being equivalent to the screw interlocking gear 42 described above, and the screw 24b, 25b side has the same structure, so the description is omitted.

As shown in FIG. 16 (a), the screw 24a screwed to the drum base 18 and the screw 25a screwed to the lead ring 17 are simultaneously operated by the two-stage gear 60, and the two screws 24a, 25a Since the operation amounts are different from each other, it is necessary to adjust the meshing position of the gears when meshing with the two-stage gear 60. Therefore, as shown in FIGS. 16B and 16C, the screw 2
4a, 25a and the when adjusting the meshing position of the two-stage gear 60, the large diameter gear 60a of the gear portion 24a ₁ of the two-stage gear 60 of the screw 24a is retracted downwardly, and the gear portion 25a ₁ of the screw 25a In order to retract the small-diameter gear portion 60b of the two-stage gear 60 from below, and maintain the meshing state after adjusting the meshing position, the displacement member 65 as shown in FIG. It is provided above.

The displacement member 65 is made of a resin material that can be elastically displaced and is formed in a substantially equilateral trapezoidal shape.
The two-stage gear 60 is mounted on the upper surface 65 a side of the fifth gear 5. A shaft 6 supporting the second gear 60 below the second gear 60.
6, a center hole 65 formed on the upper surface 65a side of the displacement member 65.
a ₁ is fitted to the support table 51 so as to be vertically movable.
The displacement member 65 extends downward into the hole 51a formed in the support base 51 so that the two legs 65b can be elastically displaced in the left-right direction.
5b engaging portion 65b ₁ to the intermediate part are respectively protruded toward the outside claw each other.

When adjusting the meshing position between the screws 24a, 25a and the second gear 60, the displacement member 65 is adjusted.
When displacing inside each other two legs 65b of, since the engaging portion 65b ₁ formed in the middle portion of the two legs 65b can enter into the hole 51a of the support base 51, the displacement member 65
Is lowered on the support table 51 along the axis 66, and accordingly, the two-stage gear 60 mounted on the displacement member 65 is also lowered downward along the axis 66, and the dotted line in FIGS. A state is obtained. Here, if the screws 24a and 25a are respectively rotated by an appropriate amount, the meshing position can be adjusted.

On the other hand, as shown in FIG. 16D, when the adjustment of the meshing position is completed, the two legs 65 of the displacement member 65 are set.
b is lifted upward, and when the locking portion 65b ₁ formed at the intermediate portion of the two legs 65b escapes upward from the hole 51a of the support base 51, the two legs 65b expand left and right. the force, the locking portion 65b ₁ is locked on the support stand 51. Along with this, the two-stage gear 60 placed on the displacement member 65 also moves upward along the axis 66, and the screws 24a,
The meshing state with 25a is maintained in the solid state in FIGS. 16 (b) and 16 (c). At this time, the large-diameter gear portion 60 of the two-stage gear 60
a and the end faces of the small-diameter gear portion 60b move upward from below to the gear portion 2 of the screws 24a and 25a.
Chamfering is performed so as to easily mesh with 4a ₁ and 25a ₁ .

Next, the displacement member 65 described above is
1 is provided so as to be movable up and down.
The displacement members 67 having the shapes shown in FIGS.

The displacement member 67 of the modification shown in FIGS. 17A to 17D is slidably provided on the support table 51. In FIG. 17, illustration of the screw 25a is omitted. The displacement member 67 is formed in a substantially trapezoidal shape,
The bottom surface 67 a is placed on the support table 51, and
a lower surface 67d is formed at the lower end of the inclined surface 67c between the lower surface 67a and the upper surface 6c.
7b is formed substantially in parallel. Further, a guide groove 67e penetrating a part of the upper surface 67b, the inclined surface 67c, and the lower surface 67d is formed in the displacement member 67 in the longitudinal direction.
A guide groove 67e is slidably fitted to a shaft 66 that supports the second gear 60 below the second gear 60. The two-stage gear 60 includes an upper surface 67 b of the displacement member 67 and an inclined surface 67.
c, It can move up and down along the lower surface 67d.

When adjusting the meshing position between the screws 24a, (25a) and the second gear 60, FIG.
As shown in (a) and (b), the lower surface 6 of the displacement member 67
7d so that the two-stage gear 60 can be mounted thereon.
, The two-stage gear 60 descends along the axis 66, so that meshing with the screws 24a and (25a) can be adjusted.

On the other hand, as shown in FIGS. 17C and 17D, when the adjustment of the meshing position is completed, the displacement member 6 is placed on the upper surface 67b of the displacement member 67 so that the two-stage gear 60 can be mounted.
7 slides, the two-stage gear 60 rises along the shaft 66, so that the meshing state with the screws 24a and (25a) is maintained.

Next, a structure for restricting the movable range of the screws (24a) and 24b screwed to the drum base 18 in the driving means 60 will be described with reference to FIGS. In FIG. 18, (a) to (c)
Corresponding to the movable position of the screw 24b shown in FIG.
(D) to (f) show the rotational position of the reset gear 62 and the photonics sensor 64, and the description will focus on the screw 24b near the reset gear 62 side.

First, as shown in FIGS. 18A and 18D, the lower end of the screw 24b screwed to the drum base 18 extends toward the support base 51 attached to the drum base 18. Further, the lower end of the screw 24b, with is provided a gear portion 24b ₁ integrally on the rear side of the drum base 18, by rotatably supporting a lower end extending into a hole 51b bored in the support base 51 I have. Also, the screw 24b moves up and down linearly with the rotation, and moves along the entire drum correction angle characteristic shown in FIG. 15 as described above, as shown in FIG. In this state, the screw 24b has reached a substantially central position of the dead zone position shown in FIG. 15, and is in a normal reproduction mode described later. Here, K: the distance between the drum base 18 and the supporting stand 51, _K 1: distance screw 24b in FB reproduction mode is moved upward from the substantially central position of the dead zone, _{K 2:} axial gear portion 24b ₁ Assuming that the distance between the upper end and the lower end (distance between both ends), and K ₃ is the distance that the screw 24b moves down from the substantially center position of the dead zone in the FF reproduction mode, the total movable amount of the screw 24b becomes K ₁ + K ₃ . the distance K between the drum base 18 and the support base 51, by setting in advance so that the size of _{K = K 1 + K 2 +} K 3, can restrict the range of movement of the screw 24b.

That is, when the distance K between the drum base 18 and the support table 51 is set as described above, when the position of the screw 24b shown in FIG. There is a distance _{K 1} between the upper end parts 24b _1, and, there is a distance _{K 3} between the lower end and the support base 51 of the gear portion 24b _1.

[0083] Further, FIG. 18 (b), the as shown in (e), when the screw 24b to the FB reproduction mode is moved upward from the dead zone position, the gear portion 24b ₁ upper end of the screw 24b in contact with the drum base 18 upward movement is restricted, the distance _K 1 + _{K 3} is formed between the lower end and the support base 51 of the gear portion 24b _1.

[0084] Further, FIG. 18 (c), the as shown (f), the when the screw 24b to the FF reproduction mode moves downward from the dead zone position, the screw 24b the lower end of the gear portion 24b ₁ is brought into contact with the support base 51 downward is restricted, the distance _K 1 + _{K 3} between the upper end of the drum base 18 and the gear portion 24b ₁ occurs. Since the movable range of the screw 24b is regulated by the distance K set between the drum base 18 and the support table 51 as described above, the screw 24b can be prevented from rotating excessively.

Next, the positioning of the reset gear 62 in the driving means 60 will be described with reference to FIGS.
This will be described in combination with (b).

The reset gear 62 is connected to the second gear as described above.
It is provided so as to be decelerated from the two-stage gear 61 connected to the helical gear 59 and rotate within a range of approximately ± 180 °,
This is provided to reset the pulse counter PC. At this time, as shown in FIGS. 19 (a) and (b), the reset gear 62 is provided with an adjustment hole 62b through which an adjustment positioning pin 68 can be inserted at a predetermined position. An adjustment hole 51c is also formed in the support base 51 in correspondence with the hole 62b.

Here, when positioning the reset gear 62, first, the two-stage gear 61 meshed with the screws 24b and 25b and the two-stage gear 60 meshed with the screws 24a and 25a are lowered and meshed. The state is released, and the adjustment positioning pin 68 is inserted into the adjustment hole 62b of the reset gear 62.
And the reset gear 62 is temporarily fixed to a predetermined position with respect to the support table 51 by inserting the reset gear 62 into the adjustment hole 51c of the support table 51.

Next, while measuring the inclination angles of the upper and lower drums 11 and 12 and the lead ring 17 coaxially supported on the drum shaft 14 with a dial cage, for example, the inclination angles of the lower drum 12 and the lead ring 17 are measured. 14 is adjusted by turning each of the right screws 24b and 25b in FIG. 14 so as to obtain the respective inclination characteristics (FIG. 15) in the predetermined FB reproduction mode. Then, the positioning pin 68 for regulating the rotation of the reset gear 62 is removed. Then, the screws 24b, 2
The motor 52 is rotated by a predetermined number of pulses in the direction in which 5b is lowered. Here, the left screw 24 in FIG.
a and 25a are adjusted so that the inclination angles of the lower drum 12 and the lead ring 17 have the respective inclination characteristics (FIG. 15) in the predetermined FF reproduction mode.
The two-stage gear 60 meshes with the gears a and 25a, and all adjustments are completed.

After the adjustment as described above, the motor 52
Is rotated a later-described normal playback mode, i.e., first, second rotation fulcrum _{(18e 1,} 18e _2), lead ring 17 _(18f 1, 18f ₂₎ formed in the drum base 18 (17e ₁ , 17e ₂ ), and (17e ₁ , 17e ₂ )
(17f ₁ , 17f ₂ ) While the lower drum 12 abuts, the screws 24a, 24b and the screws 25a, 2
5b is separated from the lower drum 12, the photonics sensor 64 detects the edge of the light shielding plate 62a of the reset gear 62, and the pulse counter PC can be reset by this signal. The reset position is the dead zone shown in FIG. Can be made to correspond to a substantially central position.
Therefore, by using the positioning pin 68 for adjustment,
The positioning of the reset gear 62 can be performed with good workability, and the performance of the track correction (primary correction) and the lead correction (secondary correction) of the drum structure 10B can be favorably maintained after the adjustment.

Next, the operation of the drum structure 10B having the above configuration will be described with reference to FIGS.
This will be described with reference to FIG. In the following description, the direction described as 0 ° indicates the left side via the drum shaft 14 and the magnetic tape entrance side during normal reproduction, and the direction described as 180 ° indicates the right side via the drum shaft 14. 1 shows the magnetic tape exit side during normal reproduction. FIG. 20 is a schematic diagram for explaining the operation of the drum structure in the magnetic recording / reproducing apparatus according to the present invention, and FIG. 21 is a diagram showing the relationship between the entire drum correction, the track correction, and the lead correction in the drum structure.

First, as shown schematically in FIG. 20A, when recording or reproduction is performed on a magnetic tape T running at a standard speed, for example, in a normal reproduction mode, the magnetic tape T is supported coaxially on the drum shaft 14. The upper and lower drums 11 and 12 and the lead ring 17 are held substantially parallel to the drum base 18 without being inclined with respect to the drum base 18. That is, the first rotation fulcrum 18 on the drum base 18
e ₁ , 18e ₂ and second pivots 18f ₁ , 18f
₂ and the first rotation fulcrum 17e ₁ , 1 on the lead ring 17
7e ₂ and the second pivot point _17f 1, 17f ₂ and is in contact with the rear surface of the bottom portion 12c of the lower drum 12. On this occasion,
Screws 24a and 24b screwed to drum base 18
Is retracted downward without contacting the positioning pins 27a, 27b (FIG. 10) fixed to the bottom surface 12c of the lower drum 12, while the screws 25a, 25b screwed to the lead ring 17 are also attached to the bottom surface of the lower drum 12. The pins 28a and 28b (FIG. 11) fixed to 12c are retracted downward without contacting them. The lower drum 12 is a lower drum 1
Compression spring 31 narrowly mounted between drum 2 and drum base 18
a and 31b (FIGS. 11 and 12) are urged toward the drum base 18 by the strong urging force,
Is pressed toward the lower drum 12 by a weak urging force of compression springs 29a and 29b (FIG. 11) tightly mounted between the lead ring 17 and the drum base 18, so that the lower drum 1
Numeral 2 is reliably supported on the four pivot points described above while maintaining the height dimension, and the lead ring 17 is also reliably supported while maintaining the height dimension. Therefore,
The imaginary central axes of the drum shaft 14 and the lead ring 17 coincide with high accuracy, and these axes are perpendicular to the drum base 18. In this state, the magnetic tape T recorded in the standard mode is guided at its reference edge Te by the lead 17a of the lead ring 17 and at a predetermined speed corresponding to the normal reproduction mode (33.35 per second in the case of the VHS VTR).
mm), the rotation trajectories of the magnetic heads 13a and 13b coincide with the track patterns recorded on the magnetic tape T, and as shown in FIG.
2, a reproduction signal corresponding to a dead zone portion where the inclination angle of the lead ring 17 does not change, and showing a good envelope as illustrated in FIG. 2A is obtained. Here, the case where the normal reproduction mode is designated by the mode designation means (not shown) has been described. However, when the so-called recording mode for recording on the magnetic tape T running at the standard speed is designated, the drum shaft 14 and the read ring 17 A similar operation is performed for adjusting the inclination angle of the virtual center axis.

Next, as shown schematically in FIG. 20B, when recording or reproduction is performed on the magnetic tape T traveling in one direction (+ direction) at a speed different from the standard speed, for example, a normal To change from the reproduction mode to the FF reproduction mode, the motor 52 (FIG. 14) is driven, and the screws 24a and 25a on the 0 ° side are driven in accordance with the double speed of the fast-forward.
Is rotated in the direction of pushing upward. At this time, 18
Screws 24b and 25b on the 0 ° side are screws 24
a, lower drum 1 for reversing with respect to the rotation direction of 25a
It is rotating in the direction to retract from 2.

That is, when the 0 ° screw 24a screwed into the drum base 18 is pushed upward, the upper end thereof is fixed to the positioning pin 27a (FIG. 10) fixed to the 0 ° bottom surface portion 12c of the lower drum 12. ), The second rotation fulcrum 18 on the 180 ° side on the drum base 18.
The bottom surface portion 12c on the 180 ° side of the lower drum 12 abuts against f ₁ and 18f ₂ , while the first rotation fulcrums 18e ₁ and 18e ₂ on the 0 ° side on the drum base 18 are in the lower drum 12. It is separated from the bottom surface 12c on the 0 ° side. Thus, the upper and lower drums 11 and 12 coaxially supported on the drum shaft 14 together with the lead ring 17 are compressed by the compression springs 31 a and 3.
1b (FIGS. 11 and 12), and turns clockwise around the second turning fulcrums 18f ₁ and 18f ₂ on the drum base 18 against the urging force of FIG.

Therefore, the upper and lower drums 11 and 12 coaxially supported on the drum shaft 14 together with the lead ring 17 are moved clockwise with respect to the drum base 18 by the whole drum correction inclination angle θ shown in FIGS. And the whole drum is corrected, and the entrance side of the magnetic tape winding is displaced upward,
The outlet side is inclined so as to be displaced downward, and follows the overall drum inclination angle characteristic at the time of FF shown in FIG. 15 according to the tape running speed.

At the same time as the screw 24a is pushed out, the 0 ° screw 25a screwed to the lead ring 17 is also pushed upward in FIG. When it comes into contact with the pin 28a (FIG. 11) fixed to the portion 12c, the reaction force causes the second rotation fulcrum 17 on the 180 ° side on the lead ring 17 to move.
The bottom surface portion 12c on the 180 ° side of the lower drum 12 abuts against f ₁ and 17f ₂ , while the first rotation fulcrums 17e ₁ and 17e ₂ on the 0 ° side on the lead ring 17 are out of the lower drum 12. It is separated from the bottom surface 12c on the 0 ° side. As a result, the bottom surface portion 17c on the 0 ° side of the lead ring 17 is connected to the second rotation fulcrum 17f ₁ on the 180 ° side on the lead ring 17.
Mainly 17f _2, FIG. 1 in the direction to push down against the lower drum 12 against the urging force of the compression spring 29a (FIG. 11)
5, and track correction by the inclination angle theta ₁ rotates counterclockwise as shown in FIG. 21 FF reproduction mode of the track correction (primary compensation) is performed.

The track correction in this FF reproduction mode (1
The next correction) is performed on the lead ring 17 with respect to the lower drum 12 such that the recording trace formed on the magnetic tape T and the rotational trajectory surfaces of the magnetic heads 13a and 13b coincide with each other.
By rotating the lead ring 17 in the direction of pushing down, that is, in the direction opposite to the direction of the overall drum correction, the magnetic tape is displaced in opposite directions at the entrance and exit sides.

Then, the lead correction inclination angle θ _{2 obtained} by subtracting the track correction inclination angle θ ₁ by the screw 25 a screwed to the lead ring 17 from the entire drum correction inclination angle θ by the screw 24 a screwed to the drum base 18. Lead correction is performed. This lead correction (secondary correction)
The upper and lower drums 11, which are coaxially supported on the drum shaft 14 together with the lead ring 17 with respect to the drum base 18 so that the leads 17a of the lead ring 17 are aligned with the reference edge Te of the magnetic tape T, 12, by inclining the opposite direction by the lead correction angle of inclination theta ₂ minutes of each other at the inlet side and the outlet side of the with the magnetic tape winding, the inlet side is displaced upward dated magnetic tape winding, the outlet side is displaced downwardly In addition, according to the tape running speed, the motor follows the read correction inclination angle characteristic at the time of FF shown in FIG. The lead correction during the FF reproduction is performed by pulling the magnetic tape T in the direction of the rotation by the rotation of the drum structure 10B accompanying the track correction, so that the reference edge Te on the entrance side of the magnetic tape T with respect to the drum structure 10B. Leads 17
The lead ring 17 is rotated so that the lead 17a is aligned with the reference edge Te of the magnetic tape T because the reference edge Te tends to be pressed against the lead 17a on the exit side.

Here, even when the read correction is performed, the lead 17 and the magnetic head 1 adapted to the double speed of the fast-forward speed are used.
It goes without saying that the relative angle between the rotation locus surfaces 3a and 13b is maintained.

Therefore, even if the reference edge Te of the magnetic tape T is separated from the lead 17a by the track correction (primary correction), the reference edge Te of the magnetic tape T is changed by the lead 17a by this read correction (secondary correction). Drum structure 10B
Because it is guided stably over the entire winding range,
When the magnetic tape T runs at the desired fast-forward double speed, the rotational trajectories of the magnetic heads 13a and 13b are in a state of being coincident with the track pattern recorded on the magnetic tape T, and FIG.
As shown in (a), a reproduced signal showing the envelope in a good state is obtained.

Next, as shown schematically in FIG. 20C, when recording or reproducing is performed on the magnetic tape T traveling in the other direction (-direction) at a speed different from the standard speed, for example, a normal To change from the reproduction mode to the FB reproduction mode, the motor 52 (FIG. 14) is driven in a direction opposite to that in the above-described FF reproduction mode, and the 180 ° side is rotated in accordance with the multiple speed of the fast reverse. The screws 24b and 25b are rotated in a direction to push them upward, and the 0 ° screws 24a and 25a are rotated in a direction to retract from the lower drum.

That is, the 180 screwed to the drum base 18
When the ス ク リ ュ ー -side screw 24b is pushed upward, the upper end of the ス ク リ ュ ー -side screw 24b is the 180 ° -side bottom portion 12c of the lower drum 12.
Since the positioning pin 27 b (FIG. 10) fixed on the drum base 18 is pushed up, the first rotation fulcrum 18 on the 0 ° side on the drum base 18 is moved.
e ₁ and 18e ₂ abut on the bottom surface 12c on the 0 ° side of the lower drum 12, while the 180 ° second rotation fulcrums 18f ₁ and 18f ₂ on the drum base 18 are on the lower drum 12. It is separated from the bottom surface 12c on the 180 ° side. As a result, the upper and lower drums 11, 12 coaxially supported on the drum shaft 14 together with the lead ring 17, the compression springs 31a,
31b (see FIGS. 11 and 12), the drum is rotated counterclockwise around the first rotation fulcrums 18e ₁ and 18e ₂ on the drum base 18 to correct the entire drum. Fifteen
(2) follow the entire drum inclination angle characteristic in the FB reproduction mode shown in FIG.

At the same time as the screw 24b is pushed out, the 180 ° screw 25b screwed to the lead ring 17 is also pushed upward in FIG. When the pin a contacts the pin b (FIG. 11) fixed to the portion 12c, the reaction force causes the first rotation fulcrum 17 on the 0 ° side on the lead ring 17 to move.
While e ₁ and 17e ₂ abut on the bottom surface 12c on the 0 ° side of the lower drum 12, the 180 ° second rotation fulcrums 17f ₁ and 17f ₂ on the lead ring 17 are on the lower drum 12. It is separated from the bottom surface 12c on the 180 ° side. Thereby, the bottom surface portion 17c on the 180 ° side of the lead ring 17 is formed.
Is the first rotation fulcrum 17e on the 0 ° side on the lead ring 17
Track correction in the FB playback mode is performed by rotating around the _first and 17e ₂ in a direction (clockwise) of pressing down on the lower drum 12 against the urging force of the compression spring 29a (FIG. 11).

Then, the lead correction is performed by an amount obtained by subtracting the track correction by the screw 25b screwed to the lead ring 17 from the entire drum correction by the screw 24b screwed to the drum base 18, and the FB shown in FIG. It follows along the read correction inclination angle characteristic in the reproduction mode.

The effect of the above-described operation in the FB reproduction mode is similar to the effect of the operation in the FF reproduction mode, and a reproduced signal showing a favorable envelope is obtained.

Next, the relationship among the whole drum correction, the track correction, and the lead correction described above will be further described with reference to FIG.

That is, in FIG. 21, the correction angle θ for the entire drum is determined by the screw 24 screwed to the drum base 18.
a, (or 24b), and the lead ring 17
And the upper and lower drums 11, 12 integrated with the drum shaft 14 together with the drum base 18.
The track correction inclination angle θ ₁ is determined by a screw 25 a (or 25 b) screwed into the lead ring 17, and the lead 17 a of the lead ring 17 and the magnetic head 1
The lead 17a of the lead ring 17 with respect to the lower drum 12 is turned in the direction opposite to the inclination direction of the entire drum correction in accordance with the correction angle between the rotation locus planes of the magnetic tape T and the rotation trajectory of the magnetic tape T. This is the angle to be inclined.

On the other hand, as described above, the reference edge Te of the magnetic tape T tends to be separated from the lead 17a or pressed against the lead 17a with the track correction. If this tendency is observed, for example, in the case of the FF reproduction mode, the upper and lower drums 11 and 12 are integrated with the drum shaft 14 by the leads 17 a of the lead ring 17.
, The magnetic tape T tends to be lifted upward in FIG. 21 and separated from the lead 17a on the entrance side (near 0 °) of the magnetic tape T with respect to the upper and lower drums 11 and 12. And upper and lower drum 1
On the exit side of the magnetic tape T with respect to the magnetic tapes 1 and 12 (around 180 °), the magnetic tape T tends to be pulled downward in FIG. 21 and pressed against the leads 17a.

The upper and lower drums coaxially supported on the drum shaft 14 together with the lead ring 17 with respect to the drum base 18 in order to correct such a tendency and make the reference edge Te of the magnetic tape T coincide with the lead 17a. while the 11 and 12 maintaining the track correction angle substantially to be inclined in the same direction as the track correction angle of inclination theta ₁ is a read correction gradient angle theta _2.
The lead correction tilt angle θ ₂ is the drum overall correction tilt angle θ
From an angle obtained by subtracting the track correction angle of inclination theta _1. In other words, the relationship is θ ₂ = θ−θ ₁ (θ = θ ₁ + θ ₂ ). Further, the screw 24a, 24b and screw 25a, the relationship between the gear ratio of the drive gear 60, 61 mesh with and 25b, θ> θ ₁ is maintained.

In the embodiment, the first and second pivots provided on the lead ring 17 and the drum base 18 respectively make it possible to reduce the height of the drum structure 10B from the correction of the entire drum to the track. Although the configuration in which the correction (primary correction) is subtracted to perform the lead correction (secondary correction) has been described, the present invention is not limited to this, and the entire drum is corrected by adding the read correction to the track correction described in the conventional example. Also in the configuration, the technical idea described in FIGS. 13, 16, 17, 18, and 19 can be applied.

[0110]

According to the magnetic recording / reproducing apparatus according to the present invention described in detail above,
By changing the relative angle of the rotation trajectory surface of the magnetic head with respect to the read in accordance with each reproduction mode and recording mode, primary correction (track correction) suitable for the running speed of the magnetic tape is performed, and secondary correction (read) is performed. By changing the relative angle of the lead with respect to the drum base by the correction), the displacement of the reference edge of the magnetic tape with respect to the lead caused by the primary correction is corrected, and a good trick play without noise bars or the like is realized. Can be.

According to the first and second aspects of the present invention, the second screw screwed to the lead ring is connected to the drive gear via the coupling gear. Even if the second screw is inclined, the inclination of the second screw is not transmitted to the drive gear,
The meshing relationship between the second screw side and the drive gear can be favorably maintained.

According to the third aspect of the present invention, the operating range of the first screw screwed to the drum base is regulated by the distance set between the drum base and the support base supported by the drum base. As a result, the first screw can be prevented from rotating excessively.

[0113] In particular, according to the fourth and fifth aspects, the first screw screwed to the drum base includes:
When adjusting the second screw screwed to the lead ring, respectively, the drive gear is displaced in the axial direction using the displacement member to release the engagement between the drive gear and the first and second screw sides. Therefore, the first and second screws can be adjusted with good workability.

Further, in particular, according to the sixth and seventh aspects, the pulse counter for counting the number of rotation pulses of the motor is reset by the reset rotary member, so that the primary correction (track) by the drum structure is performed. Correction) and secondary correction (read correction), and the quality and reliability of the magnetic recording / reproducing apparatus of the present invention can be improved. In addition, the number of rotation fulcrums to the lower drum is increased as compared with the related art, and the contact area of the rotation fulcrum is increased accordingly. The magnetic recording / reproducing apparatus of the present invention can be further improved in quality and reliability because of a structure that is strong against impact resistance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a general example of a running system of a magnetic tape near a drum structure of a VTR.

FIG. 2 is a diagram showing an FM reproduction signal waveform.

FIG. 3 is a diagram showing a relationship between a recording trace pattern recorded on a magnetic tape and a rotation locus of a magnetic head during trick play.

FIG. 4 is a diagram showing a relationship between a recording trace pattern of a magnetic tape and a rotation locus of a magnetic head during trick play in a W-VHS VTR.

FIG. 5 is a perspective view showing a configuration of a drum structure employed in a conventional magnetic recording / reproducing apparatus.

FIG. 6 is a schematic diagram illustrating respective rotation fulcrums when performing track correction for correcting an upper drum and a lower drum and lead correction for correcting a lead ring in the drum structure illustrated in FIG. 5;

FIG. 7 is a view for explaining the operation of the drum structure shown in FIG. 5;

FIG. 8 is a perspective view showing a configuration of a drum structure applied to the magnetic recording / reproducing apparatus according to the present invention.

FIG. 9 is a longitudinal sectional view showing a configuration of a drum structure applied to the magnetic recording / reproducing apparatus according to the present invention.

FIG. 10 is a top view of a drum structure in the magnetic recording / reproducing apparatus according to the present invention, and a GG sectional view in which the upper surface is sectioned along the GG line.

FIG. 11 is a top view of a drum structure in the magnetic recording / reproducing apparatus according to the present invention, and an XOYZ sectional view of the top taken along the line XOYZ.

FIG. 12 is a top view of a drum structure in the magnetic recording / reproducing apparatus according to the present invention and an EE cross-sectional view of the upper surface taken along line EE.

FIG. 13 is a view for explaining a structure in which a screw screwed to a lead ring is connected by a coupling gear in the drum assembly.

FIG. 14 is a bottom view showing a driving unit mounted on the lower surface side of the drum structure in the magnetic recording / reproducing apparatus according to the present invention.

FIG. 15 is a view showing the inclination angle characteristics of the whole drum correction, the track correction, and the lead correction of the drum structure in the magnetic recording / reproducing apparatus according to the present invention.

FIG. 16 is a view for explaining a structure for adjusting a meshing position of gears when a screw screwed to a drum base and a screw screwed to a lead ring are meshed with a drive gear in the driving means.

FIG. 17 is a view for explaining a modification of the displacement member shown in FIG. 16 in the driving means.

FIG. 18 is a view for explaining a structure for restricting a movable range of a screw screwed to a drum base in a driving unit.

FIG. 19 is a view for explaining positioning of a reset gear in a driving unit.

FIG. 20 is a schematic diagram for explaining the operation of the drum structure in the magnetic recording / reproducing apparatus according to the present invention.

FIG. 21 is a diagram showing the relationship among overall drum correction, track correction, and lead correction in a drum structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording / reproducing device (VTR), 10B ... Drum structure, 11 ... Upper drum, 11a ... Tape sliding contact surface, 12 ... Lower drum, 12a ... Tape sliding contact surface, 12b ... Small diameter part, 12
c: bottom part, 13a, 13b: rotating magnetic head (magnetic head), 14: drum shaft, 17: lead ring, 17a
... lead, _17e 1, _17e 2 _... the first pivot point, 17f
₁ , 17f ₂ ... second pivot, 18e ₁ , 18e ₂ ... first pivot, 18f ₁ , 18f ₂ ... second pivot, 24
a, 24b... first screw, 24a ₁ , 24b ₁ .
1st gear part, 25a, 25b ... 2nd screw, 2
5a ₁ , 25b ₁ … second gear part, 41… coupling gear, 42… screw interlocking gear, 51… support base, 52
... motor, 60, 61 ... drive gear (two-stage gear), 62 ...
Rotating body for resetting (reset gear), 62a: reset detecting unit (light shield plate), 64: detecting element (photonics sensor), 66: shaft, 65: displacement member, 67: displacement member, 6
8 ... Positioning pin for adjustment, PC ... Pulse counter, T ...
Magnetic tape, Te: Reference edge.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Masano 3-12-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Japan JVC Co., Ltd. Examiner Hiroshi Yamazawa (56) References A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 15/61 G11B 5/588

Claims (7)

(57) [Claims] 1. A lead ring having a rotatable magnetic head mounted thereon and a rotatable upper drum and a lower drum coaxially supported on a drum shaft, and having a lead for guiding a reference edge of a magnetic tape. The lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base by being coaxially fitted with the lower drum, and are wound around a part of the peripheral surface of the upper and lower drums. When performing a recording / reproducing operation by forming an inclined recording trace at a predetermined angle with respect to a reference edge of the magnetic tape using the rotating magnetic head on the magnetic tape in a state, a recording trace formed on the magnetic tape is formed. The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the rotation locus surfaces of the rotating magnetic head coincide with the rotation trajectory of the rotating magnetic head according to the running speed of the magnetic tape. Magnetic tape winding on the upper and lower drums A primary correction for inclining in the opposite directions at the inlet side and the outlet side, and the lead ring with respect to the drum base so that the lead of the lead ring coincides with the reference edge of the magnetic tape. The upper and lower drums coaxially supported on the drum shaft are inclined in opposite directions at the entrance side and the exit side of the magnetic tape winding.
In a magnetic recording and reproducing apparatus provided with an angle correcting means having a plurality of screws for respectively performing the following corrections, the plurality of screws are a first screw screwed to the drum base and a screw screwed to the lead ring. A magnetic recording / reproducing apparatus, wherein the combined second screw is operated by a driving gear, and the second screw is connected to the driving gear via a coupling gear. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a gear portion is provided integrally with the second screw, and outer teeth of the gear portion are meshed with inner teeth of the coupling gear in a loosely fitted state. A magnetic recording / reproducing apparatus characterized in that a screw interlocking gear that rotates integrally with the coupling gear meshes with the driving gear. 3. A lead ring having a rotatable magnetic head mounted thereon and a rotatable upper drum and a lower drum coaxially supported on a drum shaft, and formed with a lead for guiding a reference edge of a magnetic tape. The lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base by being coaxially fitted with the lower drum, and are wound around a part of the peripheral surface of the upper and lower drums. When performing a recording / reproducing operation by forming an inclined recording trace at a predetermined angle with respect to a reference edge of the magnetic tape using the rotating magnetic head on the magnetic tape in a state, a recording trace formed on the magnetic tape is formed. The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the rotation locus surfaces of the rotating magnetic head coincide with the rotation trajectory of the rotating magnetic head according to the running speed of the magnetic tape. Magnetic tape winding on the upper and lower drums A primary correction for inclining in the opposite directions at the inlet side and the outlet side, and the lead ring with respect to the drum base so that the lead of the lead ring coincides with the reference edge of the magnetic tape. The upper and lower drums coaxially supported on the drum shaft are inclined in opposite directions at the entrance side and the exit side of the magnetic tape winding.
In a magnetic recording / reproducing apparatus including an angle correction unit having a plurality of screws for performing each of the following corrections, the plurality of screws are provided on a first screw side screwed to the drum base, and on the lead ring. The first and second gear portions provided on the screwed second screw side are meshed with the drive gear, and the first gear portion provided on the first screw side is connected to the drum base. Rotate between the support supported by the drum base and add the distance between the drum base and the support to the operating range of the first screw and the distance between both ends of the first gear portion. A magnetic recording / reproducing apparatus characterized in that the dimensions are set to predetermined dimensions. 4. A lead ring having a rotatable magnetic head mounted thereon and a rotatable upper drum and a lower drum coaxially supported on a drum shaft and formed with a lead for guiding a reference edge of a magnetic tape. The lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base by being coaxially fitted with the lower drum, and are wound around a part of the peripheral surface of the upper and lower drums. When performing a recording / reproducing operation by forming an inclined recording trace at a predetermined angle with respect to a reference edge of the magnetic tape using the rotating magnetic head on the magnetic tape in a state, a recording trace formed on the magnetic tape is formed. The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the rotation locus surfaces of the rotating magnetic head coincide with the rotation trajectory of the rotating magnetic head according to the running speed of the magnetic tape. Magnetic tape winding on the upper and lower drums A primary correction for inclining in the opposite directions at the inlet side and the outlet side, and the lead ring with respect to the drum base so that the lead of the lead ring coincides with the reference edge of the magnetic tape. The upper and lower drums coaxially supported on the drum shaft are inclined in opposite directions at the entrance side and the exit side of the magnetic tape winding.
In a magnetic recording / reproducing apparatus provided with an angle correction unit having a plurality of screws for performing each of the following corrections, the plurality of screws are provided on a first screw side screwed to the drum base and the lead ring. The first and second gear portions respectively provided on the screwed second screw side are engaged with the drive gear, and the drive gear is moved in the axial direction of the drive gear when adjusting the first and second screws. Wherein the drive gear is disengaged from the first and second gear portions to disengage. 5. The magnetic recording / reproducing apparatus according to claim 4, wherein said first and second gear portions mesh with said drive gear, and said first and second gear portions and said drive gear. A magnetic recording / reproducing apparatus characterized in that the drive gear is configured to be displaceable in the axial direction of the drive gear by a displacement member that is displaced between a position where the meshing of the drive gear is released. 6. A lead ring having a rotatable magnetic head mounted thereon and a rotatable upper drum and a lower drum coaxially supported on a drum shaft and formed with a lead for guiding a reference edge of a magnetic tape. The lead ring and the upper and lower drums coaxially supported on the drum shaft are supported on a drum base by being coaxially fitted with the lower drum, and are wound around a part of the peripheral surface of the upper and lower drums. When performing a recording / reproducing operation by forming an inclined recording trace at a predetermined angle with respect to a reference edge of the magnetic tape using the rotating magnetic head on the magnetic tape in a state, a recording trace formed on the magnetic tape is formed. The upper and lower drums coaxially supported on the drum shaft with respect to the leads of the lead ring so that the rotation locus surfaces of the rotating magnetic head coincide with the rotation trajectory of the rotating magnetic head according to the running speed of the magnetic tape. Magnetic tape winding on the upper and lower drums A primary correction for inclining in the opposite directions at the inlet side and the outlet side, and the lead ring with respect to the drum base so that the lead of the lead ring coincides with the reference edge of the magnetic tape. The upper and lower drums coaxially supported on the drum shaft are inclined in opposite directions at the entrance and exit sides of the magnetic tape winding.
A magnetic recording / reproducing apparatus provided with an angle correction means for performing a next correction, wherein the angle correction means comprises: first and second pivot points provided on the drum base; and first and second rotation points provided on the lead ring. 2 and a first gear portion provided on a first screw side screwed to the drum base and a second gear portion provided on a second screw side screwed to the lead ring. A reset gear having a drive gear that is decelerated from the motor and rotates, and a reset detector that is decelerated from the drive gear and rotates by approximately ± 180 ° and resets a pulse counter that counts the number of rotation pulses of the motor. A rotating body, and a detecting element for detecting a reset detecting portion of the reset rotating body, wherein the lead ring abuts on first and second pivots provided on the drum base, and The re When the lower drum comes into contact with the first and second rotation fulcrums provided on the dolly and the first and second screws are separated from the lower drum, the detection element resets the reset rotary body. A magnetic recording / reproducing apparatus characterized in that it is configured to detect a detecting unit. 7. The magnetic recording / reproducing apparatus according to claim 6, wherein when the first and second screws are operated, the first and second gear portions are engaged with the drive gear, while the first and second gears are engaged. When adjusting the second screw, the drive gear is displaceable in the axial direction of the drive gear so that the first and second gear portions are disengaged from the drive gear, and 2. A magnetic recording / reproducing apparatus, wherein the reset rotary member is temporarily fixed at a predetermined position when adjusting the screw.