JPS6310388A - Tape remainder display device - Google Patents

Abstract

PURPOSE:To display a remaining time according to the position of a changeover switch setting the type of tape cassette through the operation of a tape remainder display switch by instantaneously forwarding and rewinding a tape cassette quickly after said cassette is loaded onto a VTR. CONSTITUTION:When the type of tape cassette is automatically discriminated, a switch 17 is used as a one to specify the types of tape cassettes (T-120 and T-160) that cannot be discriminated. Before and after the tape cassette is loaded onto the VTR, the type of tape cassette that the switch 17 can specify is fast forwarded(FF) or rewound(REW), thereby calculating the tape remainder time. Thus the type can be displayed as a 1st display state. After a known VTR action at a constant tape speed, the remainder time of any type of tape cassette can be displayed as a 2nd display state. By using a display part 18 shown by broken lines, the 1st and 2nd display states can be discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a tape remaining amount display device for displaying the remaining amount of time of a tape cassette loaded in a magnetic recording/reproducing apparatus (VTR).

(b) Conventional technology Generally speaking, as with video tape recorders (VTRs), audio decks, and cassette decks, when information (including video signals and audio signals) is to be recorded on a magnetic tape, only the part of the recorded information is recorded. In order to continue recording new information, it is necessary to know the remaining amount of tape. That is, if it is a new blank cassette, for example V
In the H8 system, like T-120, T-160, etc., the recordable time is displayed on the cassette, and the S
While the user can determine the amount according to P and EP, it is necessary to know the remaining amount when additionally recording on the recorded cassette.

As an example, Japanese Patent Application Laid-Open No. 59-198581 discloses that the remaining amount time T is determined by measuring the known tape speed (■), tape thickness (a), supply reel hub diameter (r5), and the rotation period (t) of the supply reel and the rotation period of the supply reel. A technique is shown in which the tape speed is measured and calculated using the following equation.

■t1 πT1 T″″ 4Wa ” aV l υ− (4, −πr l )... (A) a υ (c) Problems to be solved by the invention In the case of the conventional example, FF (fast forward ) and REW (rewind)
Although it has the advantage of being able to calculate the remaining amount of tape even in VTR operating conditions where the tape running speed is unknown, this method only measures the reel rotation period on the supply side.
Although the detection mechanism is simple, since the entire equation (A) is divided by the tape thickness (a), the calculated remaining amount error due to the tolerance of the tape thickness (a) is large.

Therefore, as an indication of the remaining amount of time, a digital display, that is, 1-1
It is difficult to display "0 minutes", and it is necessary to use a bar graph method using display elements such as LEDs provided in units of 10 minutes or 30 minutes, for example. In addition, in the case of the VH3 system, some types of tape cassettes have different tape thickness a and reel hub diameter r, which must be known in the calculation formula, and these can be specified by the user using a switch, etc. Must be taken away. Generally, this designation is given by the name of the tape cassette so that it is easy for the user to understand. Types of tape cassettes include T-20, T-60, T-90, T-120, T-1
60 is available, and the switch position is T-20-T-
Considering the case of setting 3 positions of 60-T-90, T-120, and T-160, T-20 to T-60 to T-90 ---...-a -20 (μ) , r= 31 (Tl
lll)T-120=...a=20(μ), r-1
3(m)T-160・=-・・a-15,6(μ),
r= 13 (+1111>).

Therefore, the three positions of the above switch, especially T-120,
The T-160 had the disadvantage that it included not only tape thickness and hub diameter but also all parameters of the tape cassette as information, and the method of using this information was quite complicated.

Furthermore, on the display element, the remaining amount of time had to be displayed in accordance with the actually loaded tape cassette and each mode, ie, SP, EP, and LP.

In view of the above drawbacks, the present invention instantly displays the remaining amount of the loaded tape according to the position of the changeover switch by pressing the remaining amount display switch in advance and performing FF and REW. The purpose is to display the display state separately from the display state after passing through the mode.

(d) Means for Solving the Problems The present invention provides a supply reel and a take-up reel for transporting the tape in the tape cassette after it is installed, and rotation detection means respectively coupled to the two reels. In the magnetic recording and reproducing apparatus equipped with a capstan and a pinch roller that transport the tape at a constant speed, information processing is performed based on information from the rotation detection means corresponding to the tape type setting position by operating a remaining amount display switch. When the remaining tape amount is displayed in the first display state on the display section and the tape speed is set to a constant mode such as playback, recording, or special playback, the information processing section displays the tape type of the cassette. The tape remaining amount corresponding to the amount of tape remaining is displayed on the display section in a second display state different from the first display state.

(*) Function The present invention allows the remaining amount of tape to be immediately displayed on the display device in advance by fast-forwarding or rewinding based on information corresponding to the tape type setting switch after loading the cassette into the video tape recorder, and allowing playback. , recording or special playback, etc., VTR
When the operation mode becomes an operation mode in which the tape speed is known and constant, the type of the cassette can be automatically determined according to the operation mode, and the remaining tape time can be displayed.

(f) Embodiments To explain the present invention according to drawings, FIG. 1 is a block diagram showing a remaining tape amount display device of the present invention, FIG. 2 is a plan view of main parts of a tape cassette, and FIGS. 3 and 4 are FIG. 5 is a flowchart for explaining the operation of the device, FIG. 5 is a distribution diagram of measurement parameters used in the device, and FIG. 6 is a display state diagram of the device. In the drawing, (1) is a magnetic tape (2)
(3) is a tape cassette with a built-in tape cassette, (3) is a supply reel stand (4)
) with a supply reel shaft, (5) a take-up reel stand (6)
(7) is a pinch roller; (8) is a take-up reel shaft having a
is a capstan, (9) is a supply reel, (10) is a take-up reel, (11) and (12) are rotary plates attached to the supply reel shaft and take-up reel shaft, respectively, and (13) and (14) are the rotary plates. (15) is an information processing unit including a microcomputer, (16) is a switch for displaying the remaining capacity, (17) is a changeover switch for changing the cassette type, 18) is the display that shows the remaining tape time, (19) is the system control (
This figure shows the system control unit called sysfun (abbreviated as sysfun).

Generally speaking, the remaining amount of tape T is π(Ra”) when viewed from the supply side.
rs”) T=Completion;・ 1. (see)...■When viewed from the take-up side, 1 π(Rs"rt') T=v;-7; , , (see)
...■t, υ.

Here R8-27r scream...1 old...1 old...■t,
υ1 R・= 27r ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・Represented by ■.

In the above formula, υ. : Tape speed (m/sec) that is the target of the remaining amount
) R1: Tape radius of supply reel (3) (m) r,:
Hub radius of supply reel (3) (m) μ, : Tape thickness of supply reel (3) Cm) L : Total length of tape
(m) R1: Tape diameter radius of take-up reel (5) (m) r, hub radius of second take-up reel (5) (m) μ,: Tape thickness of take-up reel (5)
(m)t,: Reel rotation period (s) of supply reel (3)
ee ) υ, : When the reel cycle is specified - speed (m
/sec) tt: Rotation period of take-up reel (5) (see)
The above T indicates the leader tape thickness, and μ includes the air layer. The remaining time T mentioned above is the tape speed SP during recording and playback.
This is the time to the end of the tape when the tape runs at either tape speed , LP, or EP, and this tape speed is the tape speed that is the target of the remaining amount. shall be. Also, the reel cycle is measured to calculate the remaining amount of time. In addition, 1. necessary for calculating the above R and R. ．． 1. When measuring, a certain tape speed is required for convenience, and this tape speed is used as the tape speed υ when measuring the reel period.
, and so on.

From the above formula 〇, ■, formula ■, ■...
...If we eliminate υ1 from ■'■' and ■゛, we can find T by substituting the formula ■ into ■゛, where μ, = μ1, K r = K t = K.

By measuring the constants in each of the above equations, the remaining amount time T can be determined.

Next, to explain the operation of the tape remaining amount display device of the present invention, in Figs. Find the remaining amount. A supply reel (9) and a take-up reel (10) in the cassette (1) are coupled to a supply reel stand (4) and a take-up reel stand (6), respectively.

In the initial state, that is, before the VTR goes through a well-known operation mode in which the tape running speed is constant, the tape type setting changeover switch (17) is used as a switch for specifying the type of tape cassette (1). (17)
If the type of tape cassette cannot be automatically determined, for example, in the case of a VH3 video cassette, T-12
0, T-160 are included as positions, and although the example in FIG. 1 shows an example of three positions, it is also possible to add the T-30 position to make four positions.

Therefore, before the VTR goes through a well-known operation mode with a constant tape speed, the tape cassette type is designated by the tape type setting changeover switch (17).

Next, when the tape speed is constant and the operation mode is known, the above-mentioned automatic tape cassette type discrimination operation is executed, but at that time, the switch (17) is activated to switch the tape cassette type that cannot be determined (the above-mentioned T-120 and T-1
60) is used as a switch to specify.

Therefore, even immediately after the tape cassette (1) is installed in the VTR, the types of tape cassettes that can be specified by the switch (17) (especially those that are considered to be used frequently by the user) are For example, the remaining tape time can be calculated by fast forwarding (FF) or rewinding (REW).
Furthermore, after the tape speed is constant and the tape goes through the well-known VTR operation mode, it is possible to display the remaining time for all types of tape cassettes as a second display state.

Next, the main loop will be explained according to flowcharts (a) and (b) in FIGS. First, the information processing section (15)
Check the information from the system control unit (19) to see if the tape cassette has been installed in the TR. If the tape is not attached, the data indicating the remaining time of the tape is cleared, and at the same time, the display on the display section (18) is also cleared. This means that the tape cassette was ejected while the remaining tape time was being displayed.
The same applies to the case. After that, this loop continues until the tape cassette is loaded again, and even if the tape cassette is loaded, the previous remaining amount data will not be restored.

When the tape cassette is loaded, the information processing section (15) receives a signal to that effect from the system control section (19), and at the same time checks whether the tape is running.

When the tape is running, the cycles of both reels on the supply side and take-up side are determined by the rotary plate (11) (12) and the sensor (13).
Measurement is performed based on the signal obtained from (14). If the measurement of both reels is known and the tape running speed is constant, then the rotation periods of both reels on the supply side and take-up side are measured.

The system control unit (19) also checks whether the measurement of both reels was carried out at a known and constant tape running speed.
If so, the type of tape cassette is automatically determined (described later). These are displayed even if the user has not instructed the remaining amount to be displayed, and therefore the remaining tape time (or “C” or “Calculating”) is displayed.
CALC") is not displayed (for example, the tape counter is being displayed).

When the information processing unit (15) completes the measurement of the reel cycle, it calculates the remaining tape time, but the method for obtaining the necessary tape cassette parameters at this time is based on the fact that automatic tape cassette identification (described later) has already been completed. Depends on whether or not. The information processing unit (15) knows the parameter from the state of the changeover switch (17) before the automatic determination is executed, and conversely, the information processing unit (15) knows the parameter from the result if it is after the automatic determination. =12- Once the automatic discrimination of the tape cassette is executed, the result of the automatic discrimination is held in the information processing section (15) until the tape cassette is taken out (ejected).

Therefore, once the automatic discrimination is executed, even if the tape running speed is known and the VTR is not operating at a constant rate,
It is possible to display the remaining amount of all tape cassettes that are not present in the tape cassette type changeover switch.

The measurement results of the rotation period of both the reel shafts (3) and (5) on the supply side and take-up side are also the same, and once the tape runs and the measurement of the rotation period of both reel shafts (3) and (5) is completed. , even if the tape is stopped in VTR operation, the measurement results will be as follows.
It is held in the information processing unit (15).

Therefore, after the above measurement, the remaining amount can be displayed even if the tape is stopped.

On the other hand, even if a tape cassette is installed and a VTR operation is executed in which the tape is still running, if the execution time is not long enough for the rotation period of both reels to complete, the information processing section (15 ) does not yet have remaining amount data to be displayed. In this state, when the remaining capacity display switch (16) is operated (turned on), the information processing section (15) automatically fast forwards (FF) and rewinds
).

First, the information processing section (15) determines that the current VTR operating state is r.
The system control unit (
Check the information from 19). “Stop” (“5TOP”)
), and if the tape is running, "Calculating"("C" or "CALC", etc.) is displayed and normal reel period measurement is started. “Stop” (“5TOP”)
), and if the tape is stopped (such as when "5TILL" is executed), it is impossible to display the remaining amount, and the display section (1
8) is cleared, but at this time, it is also possible to display the message "Remaining amount cannot be displayed." When "Stopped"("5TOP") is confirmed, the information processing section (15) displays "Calculating"("C" or "CALC", etc.) on the display section (18),
In addition, the system control unit (19) requests a fast forward (FF) operation, and then, when the calculation of the remaining amount of tape is completed, a rewind (REW) request signal is generated from the system control unit (19). With the generation of the "stop" request signal, the tape position is returned to the state before the above-mentioned automatic fast forward (FF) and rewind (REW). (The above is referred to as automatic FF/REW in the drawings) The automatic FF/REW
When the VTR operates against the intention of the information processing section (15) (operation by the user) while executing the automatic FF/
REW will be aborted immediately.

Regarding the automatic discrimination of tape cassettes, after the rotation period of both reels is measured, if the measurement was performed at a known and constant tape running speed, the information processing unit (15) , receives a signal from the system control unit (19), and automatically determines the type of tape cassette.

From 2〇 Tυ, μ.

R, "--+ r," ・・・・・・・・・・・・
・・・・・・・・・■π From 2〇R8・=Lu knee compliance [+υ1・・・・・・・・・■π
When each side adds π 2〇 and 2〇, R, 稟 + Rt”−” ” ” + 2 r' ””
``'B) π However, μa=μt=μ, τ, w y , = r.

Also, from 2〇 and ■, 4π t,'+t *”=--]-(L // + 2πr
) = (11)υ.

According to the formula [phase], the sum of the squares of the rotation periods of both reels is determined by the tape running speed υ at the time of period measurement, the total length of the tape, the tape thickness μ, and the hub radius r, and the amount of tape wound on both reels is the same. It can be seen that it takes a constant value independent of the ratio of .

Also, this value naturally takes a different constant value depending on the type of each tape cassette. From this, both reels (9) (
If the tape running speed υ, which is the rotation period measured in step 10), is known and constant, the type of tape cassette installed can be known by calculating the sum of the squares of the reel periods.

Here, c, = υ, shown in Figure 5 showing the broach root
−”(t *”+ t t”)・・・・・・・・・・・・
......O, and the parameters (L, μ, r) of various tape cassettes include tolerances, so for example, a T-30 tape cassette has the following value range. have (Parameter distribution 4π(Lμ+2πr) in Figure 5
) cl-46> 4 W (La*μss+ 2 K T
is)≧C8-1゜・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・0Here Lse:T
Total tape length μs* of T30: Tape thickness rss of T30: Hub diameter C1-5°, C8-4° of T-30: After calculating C1 shown in the parameter formula O shown in Fig. 5, as shown in Fig. 4 The installed tape cassette is determined according to the flow.

However, behind the values shown in 2〇, T-120 and T-160
As shown in FIG. 5, they overlap, and when the CI is within this range, it is determined as T-120/T-160 based on the state of the aforementioned changeover switch (17).

As is clear from the above explanation, by operating the switch for displaying the remaining amount of tape, the first
In other words, after passing through the mode where the tape speed is constant, the accurate remaining amount is displayed in the second display state according to the installed cassette. indicate.

The first display state is shown in the display section (1) indicated by the broken line in FIG.
8> in the initial state as shown in Figure 6(a), the three-digit display elements of the display section (17) display hours from the left and minutes from the right two digits, with "-" between hours and minutes, for example. rl-20
, and as the accurate remaining time, change the display section shown by the solid line in Figure 1 to "=" between hours and minutes as shown in Figure 6 (B), for example '2: When displayed as 3QJ, the first and second display states can be distinguished.

In addition to the above-mentioned case of 3 digits and a colon as the digit configuration of the display section (18), if the display section (18) is provided with 4 digits and a colon, the colon may be replaced with, for example, "" or "", that is, rH indicating time.

Alternatively, "h" may be used.

Regarding the remaining amount for a tape cassette that is not in the position of the changeover switch (17), the first display state may be a meaningless value, but once the mode of constant tape speed is passed, the second display state may be a meaningless value. The accurate remaining time will be displayed again as a display state.

(G) Effects of the Invention According to the present invention, after a tape cassette is installed in a VTR, FF and R can be immediately set by operating the switch for displaying the remaining amount of tape.
By performing EW, you can display the remaining amount of time according to the position of the changeover switch that sets the type of tape cassette, and after setting the mode where the tape speed is constant, Since the remaining tape time can be displayed separately from the above display, the VTR user can tell whether or not the tape is in a constant tape speed mode by checking the remaining time displayed on the display. When the present invention is applied to a VTR remaining capacity display device, the effect is extremely large.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the remaining tape amount display device of the present invention, Fig. 2 is a plan view of main parts of the tape cassette, Fig. 3 is a flowchart for explaining the operation of the device, and Fig. 4 is a diagram of the device. FIG. 5 is a parameter distribution diagram for explaining FIG. 4, and FIG. 6 is a state diagram showing the state of the display section of the apparatus. (1)...Tape cassette, (2)...Tape, (
3)... Supply reel shaft, (5)... Take-up reel shaft,
(7) Pinch roller, (8) Capstan, (9) Supply reel, (10) Take-up reel, (11) (12) Rotating plate, (13) )(
14)...Photo sensor, (15)...Information processing unit, (16)...Remaining amount display switch, (17)...
Selector switch, (18)...display section, (19)...
System control unit. Figure 4 Figure 5

Claims (1)

[Claims] 1. After a tape cassette is installed, in a magnetic recording and reproducing device equipped with a supply reel and a take-up reel for transporting the tape in the cassette, and a capstan and a pinch roller for transporting the tape at a constant speed, the remaining amount is displayed. By operating the switch, the information processing unit displays the remaining amount of the tape in the first display state on the display unit based on the information from the rotation detection means corresponding to the tape type setting position, and also allows playback, recording, or special When the tape speed of playback is set to a constant mode, the information processing means causes the remaining amount of tape corresponding to the tape type of the cassette to be displayed on the display section in a second display state different from the first display state. A tape remaining amount display device characterized by displaying the remaining amount of tape.