JPH07182723A - Magnetic tape recording/reproducing device - Google Patents

Abstract

PURPOSE:To prevent unexpected pulling-out of a tape without adding a special mechanism by detecting sticking in two stages, highly accurately and reliably detecting dew condensation controlling a drum. CONSTITUTION:In order to achieve an object, tape loading for detecting sticking between a tape 1a and a head drum 4 is performed on two points, a first position in which the tape is wound on the drum a little and a second position in which a winding angle is big, in the first position a rotary head drum is drive-controlled in a rotary direction in which the tape is not pulled out from a reel and at a rotary torque only for a specified period of time and the last starting of the drum during loading is drive-controlled in a tape travelling direction without rotating the rotary head drum in the travelling direction of the tape at the time of loading, within the range for loading the tape, at the time of largely winding of the tape on the drum and a specified torque in which the tape is not pulled out of a cassette 1. Heavy dew condensation is detected on the first position and light one is detected on the second position and unexpected tape pulling-out is prevented even when a direction for pulling out the tape is the same at at the last starting time of the drum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape recording / reproducing apparatus equipped with a rotary drum device (hereinafter referred to as a drum) such as a VTR (video tape recorder) or DAT (digital audio tape recorder), and more particularly, The present invention relates to a magnetic tape recording / reproducing apparatus having a dew condensation detecting function for detecting that a magnetic tape (hereinafter referred to as a tape) and a rotary head drum of a drum are stuck to each other due to dew condensation.

[0002]

2. Description of the Related Art In a helical scan type recording / reproducing apparatus such as a VTR, since a tape is wound around a rotary head drum rotating at high speed, when the tape adheres to the rotary head drum due to dew condensation on the tape and the surface of the rotary head drum. However, there is a problem that the tape is unexpectedly pulled out from the cassette due to the rotation of the rotary head drum, the tape is wound around the rotary head drum and becomes inoperable, and the tape is damaged.

As a countermeasure against this, conventionally, a dew condensation sensor whose electric resistance greatly changes depending on humidity is provided near the rotary head drum to detect dew condensation. When dew condensation is detected, the cassette is mounted and the apparatus is operated. It was a system without reception. However, the system using the condensation sensor has the following problems. There is a possibility that a large amount of outside air will flow into the set when the cassette is installed, and if there is a large difference between the set internal temperature and the outside air temperature, the sensor response will be slow against the dew condensation on the rotary head drum, As a result, the tape loading operation is performed with dew condensation, and the tape is wound and damaged. If condensation has formed on the tape surface of the loaded cassette, it cannot be handled.

Therefore, as a countermeasure against the problems of the system using the above-mentioned dew condensation sensor, Japanese Patent Laid-Open No. 4-14984
No. 2, JP-A-4-319555, JP-A-5-
JP-A-135427 proposes a method of directly detecting sticking between a tape and a rotary head drum.

[0005]

In each of the tape and rotary head drum sticking detection methods disclosed in the above-mentioned prior applications, both of the drum and tape are detected when sticking of the rotary head drum and tape is detected. Due to the small contact area (because detection is performed with light contact), mild dew condensation cannot be detected, and the tape will be rolled up when the tape withdrawal restriction is released as the tape loading is restarted. May be damaged. Further, a mechanism for restricting the pulling out of the tape is required only at the tape loading position where the detection is performed, which causes the device to be complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic tape recording / reproducing apparatus having a dew condensation detecting system which solves the above problems and which is highly accurate and highly reliable and which does not complicate the apparatus.

[0007]

To achieve the above object, the present invention provides a tape loading position for detecting sticking of a tape and a rotary head drum to a first position where the tape is slightly wound around the drum. 2nd with a large winding angle
And at the first position, the rotary head drum is driven and controlled in the rotation direction and the rotation torque such that the tape is not pulled out from the reel for a predetermined time.
In addition, the final start-up of the drum during loading is within the range where the tape can be loaded without rotating the rotating head drum in the tape advancing direction during loading. Is controlled to rotate in the tape advancing direction with a predetermined torque that does not pull out.

[0008]

According to the present invention, the sticking of the tape can be detected at the first position for heavy dew condensation and at the second position for light dew condensation by the means described above. It is possible to improve the accuracy of dew condensation detection. Further, in the first position, since the rotating direction and torque of the rotary head drum are controlled so that the tape is not pulled out due to the sticking of the tape to the rotary head drum, the tape is pulled out unexpectedly when sticking is detected. There is no need to add a special mechanism to prevent this. Furthermore, even when the final drum is started during loading, the rotary head drum is set to the tape by setting the starting torque appropriately against the increase in the tape drawing load due to the large contact area between the fixed drum and the tape. Even if the tape is started in the pulling direction, the tape will not be pulled out unexpectedly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS. 2 to 7 show a VT according to this embodiment.
2 is a view showing the tape loading mechanism portion of R, FIG. 2 is a schematic plan view of an unloading state which is a cassette loading mode, and FIG. 3 mainly shows a drive transmission system of the tape loading mechanism portion in the same state as FIG. It is a schematic plan view.

First, the structure of the tape loading mechanism will be described with reference to FIGS. 2 and 3. In FIG. 2, on the fixed chassis 3, a drum 4, which is composed of a rotary head drum that rotates at a high speed at a predetermined speed by a drum motor (not shown) and a fixed drum having a tape guide portion, a guide slot 2a of the movable chassis 2, Guide shafts 37, 38, 39 engaging with 2b, 2c, tape guides 41, 42 forming an entrance side running path of the tape 1a pulled out from the cassette 1 to the drum 4, and tape vibration during running are reduced. An impedance roller 13, a tape guide 43 that forms an exit-side running path to the drum 4, a capstan motor 44a whose rotation axis is a capstan 44 that is a tape drive source, and a speed increasing gear 48 that engages with the movable chassis 2.
Transmission gears 49 and 50 that transmit the rotation of the speed increasing gear 48 to the loading ring 47 are rotatably provided. Further, the loading posts 53, 54, 55, which are connected to the loading ring 47 by connecting means (not shown),
A guide plate (not shown) having a guide groove 46 for moving the loading posts 53, 54, 55 is provided. An idler gear 40 that transmits the rotation of the capstan motor 44a to the supply reel base 58 or the take-up reel base 59 on the movable chassis 2 via a belt mechanism (not shown) is rotatably provided on the support shaft 40a. .

Further, by the guide slots 2a, 2b, 2c and the guide shafts 37, 38, 39 on the fixed chassis 3, the fixed chassis 3 is mounted on the movable chassis 2 which is slidable forward and backward with respect to the drum 4. Is the tape guide member 7a
A guide arm 7 in which the planting is performed, a roller arm 9 on which a pinch roller 8 is rotatably provided, and the roller arm 9
The roller operating arm 10 connected to the roller operating arm 10 and the roller driving arm 11 for driving the roller operating arm 10 are the support shaft 1
4, 15, and 32 are rotatably provided, and a tension lever 5 in which a tension post 5a is planted is rotatably provided on the support shaft 12. Here, the tension lever 5 and the guide arm 7 are urged by the springs 36 and 56 in the arrow direction. Further, a supply reel base 58 and a take-up reel base 59 for supplying and winding the tape, which have gear portions 58a and 59a to be engaged with the idler gear 40, are provided on the outer circumference. The band brake 6 is wound around the side surface 58b of the supply reel base 58. Here, one end of the band brake 6 has a band holder A61.
Through the band holder shaft 60 on the tension lever 5
Is rotatably supported by the band holder B at the other end.
It is fixed on the movable chassis 2 via 62. Further, a tape loading motor 16 connected to a gear on the back side of a movable chassis 2 described later, and a sub-brake 3 for controlling tape tension during tape loading.
4, a spring 57 acting on the sub-brake 34, a one-way brake 35 for restricting rotation of the take-up reel base 59 in the tape feeding direction, loading posts 51, 52, and a guide groove for placing and guiding the loading posts 51, 52. A guide plate (not shown) having 45 is provided, and a cassette mounting device (not shown) is provided.

FIG. 3 is a plan view showing the arrangement of components on the back side of the movable chassis 2 in the state shown in FIG. Figure 3
At the rear surface of the movable chassis 2, a cam gear A17 and a cam gear B having cam grooves for driving each mechanical element are provided.
18 and the cam gear C19, and transmission gears 21, 22 for transmitting the rotation of the output gear 20 of the reduction gear BOX (not shown) provided below the motor 16 to the cam gear A17.
Transmission gear 2 for rotatably transmitting rotation of cam gear B18 connected to cam gear A17 to cam gear C19.
4, 25, 26, 27 are rotatably provided, and a cam arm 28 for controlling the movement of the movable chassis 2 is rotatably provided on the support shaft 30. Further, a rotary switch (not shown) for detecting the rotation angle of the cam gear A17 is provided coaxially with the cam gear A17. Further, a slot 3a with which the engaging pin 28b of the cam arm 28 is engaged is provided on the fixed chassis 3.

In the above-mentioned structure of the movable chassis 2 side, the engagement pin 5 is set up on the back surface of the tension lever 5.
b penetrates the hole 2d of the movable chassis 2 and passes through the cam gear A17.
Of the cam groove 17a and the engagement pin 28a that is erected on the back surface of the cam arm 28 are the cam groove 18a of the cam gear B18 and the engagement pin 11 that is erected on the back surface of the roller drive arm 11.
b penetrates the hole 2f of the movable chassis 2 and passes through the cam gear C19.
The cam groove 19a and the engaging pin 11a that is erected on the upper surface of the roller driving arm 11 are engaged with the groove hole 10a of the roller operating arm 10, respectively. The guide arm 7 is
The hole 2 of the movable chassis 2 is planted on the back surface of the guide arm 7.
The engagement pin 7b penetrating through e and protruding to the back surface of the movable chassis 2 comes into contact with the inner peripheral surface of the hole 2e, so that the rotation is restricted. Further, in FIG. 2, a cassette 1 containing a reel 1b and a reel 1c around which a tape 1a is wound.
Is mounted so that the tension post 5a, the loading posts 51, 52, 53, 54, 55, the pinch roller 8 and the tape guide member 7a are positioned in the recess of the cassette 1 by a cassette mounting device (not shown). It is held by the cassette holder of the mounting device. The reels 1a and 1b are placed and engaged with the supply reel base 58 and the take-up reel base 59.

Next, from the unload completion state of FIG. 2 to FIG.
The loading operation for shifting to the recording / playback mode state shown in FIG. 2 and 3, the motor 1
6 forward rotation, transmission gears 21, 22, 23, cam gear A
17, cam gear B18, transmission gears 24, 25, 26, 2
7 and the cam gear C19 are driven to rotate by a predetermined amount in the direction indicated by the solid line in FIG. 3, the cam arm 28 is driven by the cam groove 18a, the tension lever 5 is driven by the cam groove 17a, and the roller drive arm 11 is driven by the cam groove 19a. Each of them is rotated by a predetermined amount in the direction of arrow A. Then, the loading posts 51 and 52 connected to the cam groove 18b of the cam gear B18 by a driving means (not shown) move along the guide groove 45 in the direction of pulling out the tape 1a from the cassette 1. The roller arm 9 connected to the roller driving arm 11 via the roller operating arm 10 rotates in the direction of the arrow in the figure.

On the other hand, the movable chassis 2 includes a cam arm 28.
Is rotated by a predetermined distance in the drum direction along the guide slots 2a, 2b, 2c. As the movable chassis 2 moves, the loading ring 47 moves to the speed increasing gear 4.
8, the transmission gears 49, 50 are rotatably driven in the direction of arrow B, and the loading ring 4 is connected by unillustrated connecting means.
Loading posts 53, 54, 55 connected to 7
Moves along the guide groove 46 as the loading ring 47 rotates. The guide arm 7 is rotated in the arrow direction by the engagement pin 7b guided by a guide member (not shown) provided on the fixed chassis 3 as the movable chassis 2 moves, and the tape guide member 7a pulls out the tape 1a from the cassette 1.

By the above-mentioned operations, the state shown in FIG. 4 (state at the first loading position described later) and the state shown in FIG. 5 (state immediately before reaching the second loading position described later) are sequentially passed. , To the loading completion state shown in FIG.

In the tape loading operation described above, the one-way brake 35 prohibits the supply of the tape from the take-up reel stand 59. As shown in FIG. 2, this is because the take-up reel stand 59 rotates in the counterclockwise direction of the arrow as the tape is pulled out, and at the same time, the take-up reel stand 59 moves.
The one-way brake 35 engaged with the gear part 59a of FIG. 2 rotates in the clockwise direction of the arrow, and the stopper 35a of the one-way brake 35 bites into the gear part 59a of the take-up reel stand 59 to prohibit the take-up reel stand 59 from rotating. is there. Therefore, the tape 1a is pulled out only from the supply reel base 58. During the tape loading, the tape 1a is given an appropriate tension by the action of the sub-brake 34.

FIG. 7 is a plan view showing a recording / reproducing state.
In the state shown in the figure, the tape 1a includes the tension post 5a, the tape guides 41 and 42, the impedance roller 13, the loading posts 51 and 52, the drum 4,
Loading posts 54, 55, 53, tape guide 4
3, the capstan 44 and the tape guide member 7a are sequentially formed to form a recording / reproducing traveling path. here,
From the loading completed state of FIG. 6, the roller arm 9 further rotates in the direction of the arrow, and the pinch roller 8 presses the capstan 44. Due to this pressing force, the pinch roller 8 and the capstan 44 rotate in the forward direction of the arrow in FIG. 7, and the tape 1a is transported in the direction of the arrow. At this time, the drum 4 normally rotates in the tape transfer direction, that is, the counterclockwise direction shown in FIG. At the same time, the idler gear 40 connected to the capstan motor 44a by a belt mechanism (not shown) is connected to the take-up reel stand 59, and the tape 1a transferred is taken up by the take-up reel 1c. At this time,
Since the take-up reel stand 59 rotates clockwise, the one-way brake 35 is naturally released. Further, the band brake 6 applies an appropriate tension to the winding tape on the supply reel base 58. The tape is transported by the mechanism having the above-described structure, and recording or reproduction is performed between the rotating drum head (not shown) on the drum 4 and the tape 1a. In the above series of operations, each tape loading position is detected by the above-mentioned cam gear A1.
This is performed by a rotary switch (not shown) provided coaxially with 7.

FIG. 8 is a block diagram showing an outline of the mechanical control system of the VTR of this embodiment. In the figure, reference numeral 100 denotes a system microcomputer that controls the overall control of the drum 4, and the system microcomputer 100 controls the drum 4 via a servo IC 101 and a drum motor driver 102 in accordance with measurement information from each unit and various control programs that are predetermined. The drum motor 103 for the rotary head drum, the servo IC 101, the capstan motor driver 104
Drive control of the capstan motor 44a via the load motor 16 and load motor 16 via the loading motor driver 105. On the other hand, the rotation information of the drum motor 103 from the sensor amplifier 106, the rotation information of the capstan motor 44a from the FG sensor amplifier 107, the rotation information of the supply reel base 58 from the supply-side reel sensor 108, and the take-up side. The reel sensor 109 indicates the rotation information of the take-up reel base 59, the cassette detection switch 110 indicates whether the cassette 1 is mounted, and the mechanical mode sensor 111 indicates the cam gear A1.
7 rotation information (mechanical mode information) and information input by the operator from the operation keys 112 are input to the system microcomputer 100.

Next, the dew condensation detecting operation which is the gist of the present invention will be described with reference to the flow chart of FIG. First, in step S1, when the cassette 1 is loaded in the cassette loading mode state shown in FIG.
This is detected at 0, and the loading operation is started at step S2 in response to a command from the system microcomputer 100. Next, in step S3, the mechanical mode sensor 11
Based on the information from 1, it is determined whether or not the tape 1a as shown in FIG. 4 is in the first loading position where it is slightly wound around the drum 4, and if it is the first loading position, the loading operation is performed in step S4. To suspend. Next, in steps S5 and S6, the drum 4 (rotary head drum)
Is driven in reverse for a predetermined time at a predetermined low voltage (rotates in the direction of the arrow in FIG. 4). At this time, the one-way brake 35
The drive control of the drum 4 is performed at an appropriate low voltage so that the tape 1a is not pulled out against the regulation force generated by. Then, in step S8, it is determined whether or not the rotary head drum of the drum 4 has a predetermined rotation speed, and the sticking state between the tape and the drum is determined. Here, if the drum has reached the predetermined number of rotations, it means that the drum is smoothly rotating with respect to the tape, and therefore it is determined that there is no dew condensation, and step S
Proceed to 9. If the drum does not reach the specified rotation speed, it is determined that the tape 1a and the drum 4 are attached to each other due to heavy dew condensation, and the process proceeds to step S16. Step S
In 16, first, the dew condensation timer is set so that the tape is not accepted for a predetermined time. Next, as shown in steps S17 to S24, a tape unloading operation,
Takes up the tape and ejects the cassette.

If no dew condensation is confirmed at the first loading position in step S8, the loading operation is restarted and the tape 1a as shown in FIG. 5 is drummed after a predetermined time, as shown in steps S9 to S14. 4, the drum 4 is started to rotate in the normal direction (the direction of the arrow in FIG. 5) at a position where the drum 4 is largely wound (a position immediately before reaching the second loading position), and a predetermined time has elapsed after the start of the normal rotation, and the loading post 55 Is position 6 indicated by the dotted line in FIG.
When moving to 3 (when reaching the second loading position)
By detecting the number of rotations of the rotary head drum of the drum 4, it is possible to determine the sticking state between the tape and the drum. In this case, if the number of rotations of the drum is equal to or higher than the predetermined number of rotations, it is determined that dew condensation has not occurred, and step S1
Go to 5. On the other hand, if the number of rotations of the drum is below the detection level, it is determined that slight dew condensation has occurred, and step S1
The operation flow after 6 is executed. Here, the drum 4 rotates in the direction in which the tape 1a is pulled out from the supply reel base 58, but since the contact area between the tape 1a and the fixed drum of the drum 4 is large and the tape pull-out load is large, the drum 4 is lowered as necessary. By controlling the voltage, the tape 1a will not be pulled out unexpectedly.

According to the above-mentioned operation, when there is no abnormality in the driving of the drum at the first and second loading positions, it is judged that the tape running state around the drum is normal, and FIG.
The loading is completed as shown in. Also, the unloading position of FIGS. 2 and 3 and the first loading position of FIG.
The position immediately before the second loading position in FIG. 5, the second loading position, and the loading completion position in FIG. 6 are information detected by the rotary switch (mechanical mode sensor 111) provided coaxially with the cam gear A17 as described above. Is recognized by the system microcomputer 100.

[0023]

As described above, according to the present invention, since the sticking detection between the drum and the tape is performed in two stages, it becomes possible to detect the dew condensation with high accuracy regardless of the degree of the dew condensation. The potential for tape damage caused by dew condensation can be greatly reduced. Further, by appropriately controlling the rotation direction and the torque of the rotary drum, the dew condensation detecting system can be realized without adding a special mechanism.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing flow of a dew condensation detecting operation according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a tape loading mechanism portion of a VTR according to an embodiment of the present invention in a cassette loading mode state (unloading state).

FIG. 3 is a schematic plan view showing a drive transmission system and the like of the tape loading mechanism in the same state as in FIG.

FIG. 4 is a schematic plan view showing a state of the tape loading mechanism portion of the VTR according to the embodiment of the present invention at the first loading position.

FIG. 5 is a schematic plan view showing a state before reaching the second loading position of the tape loading mechanism portion of the VTR according to the embodiment of the present invention.

FIG. 6 is a schematic plan view showing a loading completed state of the tape loading mechanism portion of the VTR according to the embodiment of the present invention.

FIG. 7 is a schematic plan view showing a recording / reproducing state of a tape loading mechanism section of a VTR according to an embodiment of the present invention.

FIG. 8 is a block diagram showing an outline of a mechanical control system of a VTR according to an embodiment of the present invention.

[Explanation of symbols]

 1 cassette 1a tape 2 movable chassis 3 fixed chassis 4 drum 17 cam gear A 18 cam gear B 19 cam gear C 28 cam arm 34 sub-brake 35 one-way brake 47 loading ring 51, 52, 53, 54, 55 loading post 58 supply reel stand 59 winding Reel stand

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hironori Saito, 1410 Inada, Katsuta-shi, Ibaraki Hitachi, Ltd. AV Equipment Division (72) Hideharu Ono 1410, Inada, Katsuta-shi, Ibaraki Hitachi, Ltd. AV equipment business Department

Claims (2)

[Claims] 1. A drum comprising a rotary head drum for recording and reproducing a signal by winding a magnetic tape and a fixed drum having a tape guide portion, and a cassette containing a pair of reels for winding the magnetic tape. Tape loading means for drawing out a magnetic tape and winding it around the drum to form a predetermined tape running path; a first tape loading position where the magnetic tape is wound around the drum by a certain amount; and a first tape loading. Loading position detecting means for determining a second tape loading position that is further loaded by a predetermined amount in the direction of forming the predetermined tape running path from the position, the first tape loading position and the second tape loading position Check the sticking state of the magnetic tape and the rotary head drum at the dying position. A magnetic tape recording / reproducing apparatus comprising: a sticking detecting unit which is known. 2. The sticking detection unit according to claim 1, wherein the sticking detection unit controls the pulling-out of the magnetic tape during tape loading in a state where the tape loading unit is temporarily stopped at the first tape loading position. The rotating head drum is stopped in a direction in which the magnetic tape is pulled out from one reel of the cassette and at a predetermined torque such that the magnetic tape is not pulled out from the reel due to sticking to the rotating head drum. From the magnetic tape and the rotary head drum are detected by the number of rotations of the rotary head drum after being rotationally driven for a predetermined time from the second tape roll. A predetermined time before reaching the loading position, the tape is supplied at the time of loading the tape. The second tape after the rotary head drum is rotationally activated from the stopped state in the direction in which the magnetic tape is pulled out from the other reel of the cassette and with the torque set in the same manner as the predetermined torque described above. A magnetic tape recording / reproducing apparatus, characterized in that the sticking state of the magnetic tape and the rotary head drum is detected by the number of rotations of the rotary head drum at the time of reaching the loading position.