JPH04106773A - Tape cassette - Google Patents

Abstract

PURPOSE:To much more miniaturize a recording and reproducing device by enlarging a mouse part so as to completely house a head drum and a tape traveling system, and setting energizing force to a tape reel constant at all times. CONSTITUTION:In front of an interval between a pair of tape reels 4 and 5 housed in a cassette enclosure 1, a mouse part 12 is provided to insert the head drum or the like in the case of recording or reproducing, and a pair of tape reels 4 and 5 are freely rotatably held by reel holders which are respectively movable. By moving those tape reels to the rear side of the cassette enclosure 1 together with the reel holders 8 and 9 when using the device, the mouse part 12 is enlarged and presser springs 16 and 17 to press the tape reels are fitted to the reel holders 8 and 9 so that the energizing force caused by the springs 16 and 17 to the tape reels 4 and 5 can be made constant at all times before and after moving the tape reels 4 and 5. Thus, the head drum or the like can be inserted much deeper to the inside of the cassette enclosure and can be completely housed in the mouse part, and the recording and reproducing device is miniaturized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tape cassette used in a magnetic recording and reproducing device such as a video tape recorder, and in particular, it is possible to downsize the recording and reproducing device by reducing the winding diameter of the tape. This relates to a tape cassette for short-term recording.

J Summary of the Invention: The present invention relates to a short-time recording tape cassette having a mouth portion into which a head drum is inserted, for example, in which the tape reel is moved to the rear of the cassette case together with a holder that rotatably holds the tape reel during use. This eliminates wasted space inside the cassette case and further enlarges the mouse section, making it possible to accommodate further miniaturization of recording and reproducing devices.By attaching a presser spring that presses the tape reel to the holder, The biasing force applied to the tape reel by the spring before and after the tape reel moves is always constant.

=Conventional technology 2 Conventionally, in tape cassettes used in magnetic recording and reproducing devices such as video tape recorders (VT, R), a head drum is inserted by reducing the winding diameter of the magnetic tape stored in the cassette case. A so-called short-time recording tape cassette has been proposed in which the mouse part is made larger, thereby reducing the size of the recording and reproducing device (for example, ``Japanese Patent Application Laid-open No. 171684-1198-1 and Book 1llll:
1 Utility Application No. 14573 by the applicant).

In other words, the outline of this conventional short-time recording tape cassette is shown in Fig. 7 (51).
indicates a cassette case, and a pair of tape reels (52) and (53) on which magnetic tape T is wound are rotatably housed in the cassette case (51), and the second tape reel (52) The magnetic tape T wound around the cassette 7) and (53) is passed through the semi-cylindrical guides (54a) and (54b) provided on the left and right sides of the front end of the cassette cassette (51). It is exposed in the front opening in a stretched state. A concave mouth portion (opening) (55) is formed in the front between both tape reels (52) and (53) with a large cutout in the bottom of the casing (51). Ru.

In the tape cassette constructed as shown in 2, the diameters of the tape reels (52) and (53) are formed smaller than those of a general standardized tape cassette. The mouse 1 (55) is made larger by the smaller diameter of the mouse (53).

When using this tape cassette (also the drawer guide (6Da) and (60b) on the recording/playback device side)
When the magnetic tape T is pulled forward by
A head drum (61) and a tape running system member (62) (impedance roller (6)
3), tape guide (64) (65) (66), loading post (67) (68), capstan (
69), a pinch roller (70), etc.) enter the head drum (61), and the magnetic tape T is wound around the head drum (61) (loading state), thereby performing a recording or reproducing operation.

In this case, by making the mouth portion (55) larger by the smaller diameter of the tape reels (52) and (53), the head drum (61) etc. can be moved into the cassette case (
51), it is advantageous for downsizing the speech recording and reproducing device.

[Problem to be Solved by the Invention 2] However, with a configuration in which the tape reel is simply made small in diameter, as in the conventional tape cassette for short-time recording, the mouth portion can only be made slightly larger, and therefore magnetic recording is not possible. There are limits to the miniaturization of playback devices.

Looking at the internal structure of this conventional tape cassette for short-term recording, there is wasted space on the sides and rear of the tape reel inside the cassette case. Yes, it's a mouthful.

In addition, tape cassettes generally use a reel pressing spring of t to hold down the tape reel, but in order to stabilize the rotation of the tape reel, the biasing force of the spring against the tape reel must be maintained approximately constant. There is a need to.

The present invention has been made with attention to these points, and provides a tape cassette that can effectively utilize the space inside the cassette case to further enlarge the mouth part, and that can always maintain a constant biasing force against the tape reel. The purpose is to

[Means for Solving the Problems 2] In order to achieve the above-mentioned objects, the present invention provides a mouse unit in which a head drum or the like is inserted in front between a pair of tape reels housed in a cassette case during recording or playback. In the tape cassette, the pair of tape reels are each rotatably held by a movable reel holder, and when in use, the mouth portion is enlarged by moving the reel holder together with the rear side of the cassette case. A presser spring that presses the reel is attached to the reel holder: The spring is configured so that the biasing force applied to the tape reel before and after the tape reel moves is always constant.

[Two functions] In the tape cassette of the present invention constructed in this way, under normal conditions, the tape reel is in a position compatible with a standardized general tape cassette, and in the second case, the size of the mouse part is It's not that big. When in use, the tape reel and holder are moved back to the rear corners of the cassette body (the mouse part is greatly enlarged, so the head drum etc. can be inserted further into the cassette body). As a result, it is very advantageous to further downsize the recording and reproducing apparatus.

Further, since the reel pressing spring also moves along with the tape reel, the urging force applied to the tape reel by the pressing spring before and after the movement is always constant, and the rotation of the tape reel is stabilized.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6.

In the figure, (1) shows a cassette case, and this cassette case (1) is constructed by combining an upper half (2) and a lower half (3) with screws or the like.

The external shape, dimensions, etc. of this cassette case (1) are formed in accordance with the 8-camera video standard, which is a world-wide standard.

A pair of tape reels (4) and (5) for winding magnetic tape T are rotatably housed in the upper and lower halves (2) and (3) of the cassette reel (1) constructed in this way. The magnetic tape T wound on the tape reels (4) and (5) is transferred to the cassette reel via roller guides (6a) and (6b) provided on the left and right sides of the front end of the lower half (3). (1) is led out in a stretched state through the front opening.

The tape reels (4) and (5) have hubs (4a) and (5a) around which the magnetic tape T' is wound, respectively, and upper and lower ends of the magnetic tape T wound around the hubs (4a) and (5a). It consists of upper and lower flanges (4b), (4c) and (5b), (5c) that hold the reel shaft in place, and reel shaft engagement holes (4d) and (5d) are opened in the bottom of the center of the flanges, respectively. ). And this tape reel (4) and (5)
In this tape reel (4), the diameters of the upper and lower flanges (4b) (4c) and (5b) (5c) are smaller than those of the standardized tape cassette. The length of the magnetic tape T wound in (5) (open during recording and reproduction) is shorter than the standard (for example, about 30 to 60 minutes).

Further, these tape reels (4) and (5) move inside the cassette housing (1) between a regular position determined by the 8-pressure video standard and a retracted position at the rear corner of the cassette housing (1). It has a structure that allows it to be moved when opened.

This tape reel moving mechanism is constructed as follows.

There are left and right roller guides (6) on the bottom of the lower half (3).
a) and (δb) A notch recess [7] in the shape of a large notch is formed in the rear part of the magnetic tape T that is stretched open, and is positioned above the second notch recess (7). A pair of reel holders (8) and (9) are placed inside the cassette case (1).
) is provided. This reel holder (8) and (
The reel holders (8) and (9) are pivotally supported at the left and right ends of the cassette reel body (1) by supports $111<10) and (11), respectively, so as to be rotatable in the front and rear direction. ) tape reels [4] and (5) are rotatably held, respectively. That is, the reel holders (8) and (9) have support plate parts (on which the tape reels (4) and (5) are placed, respectively).
8a) and (8a) and tape reels (4) and (5)
A shielding wall (8b) provided to cover the front and inside of the
) and (9b), and the support plate part (8a) and (
Reel holding holes (8C) and (9C) are drilled in 9a), respectively, and tape reels (4) and (5) are inserted into the reel holding holes (8C) and (9C), respectively, with the reel shaft engaged on the bottom surface thereof. The mating holes (4d) and (5d) are loosely engaged and held by ring protrusions (4e) and (5e) protruding from the opening edges of the holes (4d) and (5d).

The opening of the shielding parts (8b> and (9b) of the reel holders (8) and (9) on both sides, and the concave space formed in front of the openings of the shielding parts (8b) and (9b) of the reel holders (8) and (9) on both sides, and the concave space formed in front of the openings of the reel holders (8) and (9) allow the mouse head drum, etc., to be inserted during recording or playback. (12), that is, the reel holder (
8) and (9) are rotated, the tape reel (
4) and (5) move, and the size of the mouse part (12>) becomes variable.

Furthermore, on the bottom of the lower half (3), there is a reel holder (8).
Relief recesses (7a) and (7b), which follow the rotation locus of the reel holders (8) and (9), correspond to the reel holding holes (8C) and (9C) of (9), and the cutout recesses ( 7)
It is formed continuously on the left and right.

Also, from the notch recess (7) of the lower half (3), there is a table 8 on the bottom surface.
The support plate portions (8) of both reel holders (8) and (9)
Parts of a) and (9a) are used as positioning reference planes when mounted on the recording/reproducing device, and the portions (which do not interfere with the lower noof (3) during rotation) are the lower noof (3). ) is formed into a flat surface that protrudes one step so that it is flush with the bottom surface of the

In addition, roller guides (13a) and (131]) are fitted and supported on the rotation centers of both reel holders (8) and (9), that is, support shafts (10) and (11), respectively. The magnetic tape T wound around the tape reels (4) and (5) is guided by these roller guides (13a) and (1).
31]) Roller guide at the front end via 6a)
and (6b), and is exposed at the front opening of the cassette case (1).

In addition, detection light for detecting the top/end of the magnetic tape T passes through the left and right side walls of the lower half (3) and the shielding walls (8b) (9b) of both reel holders (8) (9). Through holes (14) and (15) are formed respectively.

Reel pressing springs (16) and (17) in the form of leaf springs are attached to both reel holders (8) and (9) to press and support the tape reels (4) and (5).

These 71-le pressing springs (16) and (17) are at the proximal ends, respectively! (16a) and (17a) are the reel holder (8
) and (9), the pivots (10) and (11
) is fixed to the upper end side of the free end (161
1) and (171m) are tape IJ-rules (4
) and (5) are abutted and suppressed by the center protrusions (4f) and (5f). Press this reel (16) and (17)
), the tape reels (4) and (5) are biased downward, and the lower flanges (4C) and (5C) are attached to the support plate parts (8a) and (9a) of the reel holders (8) and [9].
It is designed so that it comes into contact with and is supported.

Furthermore, a D7 mechanism (18) for locking the tape reels (4) (5) and reel holders (8) (9) is constructed at the rear part of the cassette case (1).

This locking mechanism (18) is constructed as follows.

In the center of the rear part of the cassette case [1] is a bottom hole (3).
A four-pronged member (20) is disposed so as to be movable in the front-rear direction along a smooth guide portion (19). This locking member (20) has a pair of claw portions (21a) and (21tl) protruding forward at both left and right ends thereof.

- Engagement grooves (22a) and (22) are provided at the rear of both reel holders (8) and (9), corresponding to the claw pieces (21a) and (21b) of the crab locking member (20), respectively.
b) is formed in the shape of a notch, and both tape reels (4
) and (5), engagement teeth (23a) and (23b> are formed over the entire outer periphery of the lower flanges (40) and (5C), respectively.

A compression coil spring (24) is inserted between the lock member (20) and the rear wall of the lower half (3), and the biasing force of the compression coil spring (24) causes the lock member (20) to
) jAlmost in front, that is, the claw pieces (21a) and (2
1b> is the engagement groove (
22a) and (221)), and tape reel (
Engaging teeth (23a) and (23b) of 4) and (5)
is biased in the direction of engagement.

There is an operation hole (20a) in the center of the lock member (20).
Correspondingly, an insertion hole (25) is formed in the bottom of the lower /'%-fu (3), and as will be described later, the tape cassette of this example is installed in a recording/reproducing device. In this case, the release member is inserted into the operation hole (20a) of the lock member (20) from the recording/reproducing device side through this insertion hole (25), and the tape reel (4) of the lock member (20) is engaged.
) and (5) are unlocked.

At the bottom of the lower half (3), a cut groove (26) is formed in front of the insertion hole (25) toward the rear of the edge of the cutout recess (7), as will be described later. When the tape cassette of this example is installed in a dedicated recording and reproducing device, a release member is inserted from the recording and reproducing device side through this notch (26), and this release member locks the locking member (20).
The lock release operation for the reel holders (8) and (9) is performed from the two points where the front end surfaces (2011) of the reel holders (8) and (9) are pressed.

There is also a glue pad (front cover) on the @ part of the cassette case [1] to protect the surface side of the magnetic tape T that is exposed in a stretched state between the left and right roller guides (6a) and (6b).
(28) is attached so that it can be rotated to open and close.

The lid (28) has side walls (28a) and (28kl) extending at right angles to both ends thereof,
By inserting and engaging the shafts (29) protruding from the inner surfaces of the side walls (28a) and (28b) into the shaft holes (30) formed at the front ends of both side walls of the upper half (2), It is pivoted so that it can rotate freely in the direction. This lid (28) is always biased to close in the closing direction covering the surface side of the magnetic tape T by a screw spring (31) fitted to the shaft (29) on the blade side. When the magnetic tape T is attached to a recording/reproducing apparatus, the lid (28) is opened and rotated upward by the lid opening mechanism of the recording/reproducing apparatus, exposing the magnetic tape T.

Furthermore, behind this lid (28), there is a back lid (32) for protecting the back side of the magnetic tape T.
is installed.

This batter lid (32) includes a batter lid main body (33) that covers the back side of the magnetic tape T, and a concave a (2a) formed on the upper surface side of the upper half (2) as a relief when the hack lid main body (33) is opened. ) and a top plate (34) that covers the top plate (34).
4) is integrally connected via the connecting part (35))
Ru.

A shaft projection (36) is formed on the left and right edges of the butterfly lid main body (33), and this shaft projection (36) is attached to the lid (
The batter lid (32) is rotatably connected to the lint (28) by a pair of support pieces (37) protruding from the back side of the battery lid (28).

The batter lid (32) also has engagement pins (38) that protrude on both the left and right sides, and guides that protrude on the left and right sides of the front end of the lower half (3) corresponding to the engagement pins (38). A cam groove (40) of a predetermined shape is formed in the wall (39), and the engaging pin (38) is engaged with the lid (28).
When the hack lid (32) is rotated to open and close, the engaging pin (38) is guided along the cam groove (40), thereby causing the hack lid (32) to open and close following the lid (28).

In the case of the tape cassette of this example, the head drum, etc. enters the mouth part (12) during loading, which will be described later, and the lid (28) is closed even when the magnetic tape T is drawn into the mouth part (12). It has a special structure that allows it to

That is, in this tape cassette, gaps a are provided on both left and right sides of the batter lid (32), through which the magnetic tape drawn into the mouth portion (12) passes. To explain this in more detail, in this example, the top plate (
An arm (41) is provided to protrude downward from both left and right ends of the arm (41), and engagement pins (38) are formed outwardly at the lower end of the arm (41).
1) and the back lid body (33), the required clearance a
It has a structure with And the mouse part (12)
As the magnetic tape T drawn in passes through this gap a, the batter lid (32), which is operated following the lid (28), will not interfere with the magnetic tape T, and therefore the lid (28) will not interfere with the magnetic tape T in any way. Now it can be closed without any problems.

Furthermore, in the tape cassette of this example, the mouse part (1
2) In order to prevent the magnetic tape T being drawn in from interfering with the guide (39) of the lower half (3), the front edge of this guide wall (39) is attached to the roller guide (6a) and (39), respectively.
6b) is formed so as to be set back to a greater extent, so that a required gap is formed between the lid (28) and the lid (28) in the closed state.

In addition, on the upper surface of the upper half (2), there is a relief groove (42) that is continuous with the concave portion (2a) and serves as a relief for the arm (41) of the butterfly lid (32) when the lid (28) is opened. is formed.

Next, the operation of the tape cassette of this embodiment constructed as above will be explained.

First, in the normal state (□,), the tape reels (4) and (5) are in the fixed position determined by the 8N video standard, as shown in Figure 1, and in this state, the locking member (20) holds the reels. The tape reels (4) and (22a) and (22b) of the bodies (8) and (9)
5) is engaged with the (system gear teeth (23a) and R (23b), thereby holding the reel holder (8) and (
9) are locked with the tape reels (4) and (5) respectively in place, and at the same time the tape reels (4) and (5) are locked in place.
5) is also locked so that it cannot rotate.

As mentioned above, in the tape cassette of this example, the positions of the tape reels (4) and (5) are in the fixed positions determined by the 8-video standard in the normal state, so it can be used as a general 8-8 tape cassette without using any special adapters. It can be used in the same way as a video cassette.

That is, when this tape cassette is installed in a standard type recording and reproducing device that complies with the 8B video standard, a release member (not shown) is inserted into the locking member (20) from the recording and reproducing device side through the insertion hole (25). is inserted into and engaged with the operation hole (20a),
By this release member, the lock member (20) is moved backward against the biasing force of the compression coil spring (24), and the claw piece (
21a) and (21b) are tape reels (4)
and (5) engaging teeth (23a) and (23b)
The tape reel (4) and [
5) becomes rotatable (see Figure 2).

When used in a standard recording/playback device like this,
The claw pieces (21a) and (21b) of the O-/ri member (20)
) are the engagement teeth (23a) of the tape reel (4) and [5]
and (23b), and the reel holder (8)
and engagement grooves (22a) and (22b) of [9]
are still engaged (), so only the rotational lock of tape reels (4) and (5) is released and the positions of tape reels (4) and (5) are held in place. Therefore, it is no different from a general 8-hole video cassette (it can be used (compatible) with standard recording and reproducing equipment).

On the other hand, when the tape cassette of this example is installed in a dedicated recording/playback device that does not conform to the 8mm video standard, a release member (not shown) is inserted from the dedicated recording/playback device side through the notch (26). Front end surface (2) of the member (20)
0b), thereby locking member (20)
is moved backward to a greater extent than in the case of the above-mentioned advancement, and the claw pieces (21a) and (21tl) engage the engaging teeth (23a) and (21tl) of the tape reels (4) and (5).
23b), and also reel holders (8) and (9)
The tape reels (4) and (5) are made rotatable, and the reel holders (8) and (9
) can also be rotated (see Figure 3).

When the reel holders (8) and [9] are unlocked in this way, the reel holders (8) and (9) are moved to the spindles (10) and (11) by the moving mechanism of the recording and reproducing device, respectively.
), that is, the tape reels (4) and (5) are moved to the rear corner of the cassette case (1), so that the mouse part (12) is moved to a large extent. It will be in an enlarged state (see Figure 4).

By enlarging the mouse part (12) in this way, the head drum (61) and tape running system members (62) (impedance roller (63), tape guide (64) (65
) (66), loading post (67) (68),
The capstan (69), pinch roller (70), etc.) can be completely housed within the mouse portion (12).

To briefly explain the tape loading operation of this recording and reproducing apparatus, among the tape running system members (62), the tape guide (64) (6D) (66), the loading position l-<67) (68), Hon Yapustan (69)
is installed on the side of the main body of the recording/reproducing apparatus, and is positioned at the mouse part (12) gate with a tape cassette attached. On the other hand, a drum (61), an impedance roller (63), and a pinch roller (70) are provided on a movable plate that is movable with respect to the main body of the recording and reproducing device, and are arranged on a movable plate that is movable with respect to the main body of the tape cassette. Before installing the mouse part (1
2) is located outside of When the tape cassette is installed, the movable plate moves and moves the head drum (61), impedance roller (63), and pinch roller (70).
is inserted into the mouth part (12) from the front of the cassette, and thereby the magnetic tape T stretched between the roller guides (6a) and (6b) is drawn into the mouth part (12) and placed on a predetermined tape bus. At the same time, the loading posts (67) and (68) move in an arc around the head drum (61) to load the magnetic tape onto the head drum (61).
1) and loading is completed.

The above loading operation is performed with the lid (28) open (the lid (28) is opened by the lid opening mechanism of the recording/playback device when the tape cassette is installed), but this is not the case with the tape cassette of this example. As mentioned above, all of the head drum (61) and tape running system member (62) are completely accommodated within the mouth part (12).
The lid (28) can be closed again after loading is completed.

At this time, as mentioned earlier, since there is a gap a on both left and right sides of the batter lid (32) through which the magnetic tape T passes, the batter lid (32) does not interfere with the magnetic tape.
Therefore, the lid (28) can be opened smoothly and reliably without any hindrance.
can be closed.

As mentioned above, in the tape cassette of this example, the mouse part (1
2) is greatly enlarged, so that the head drum (61) and tape running system members (62) are fully loaded.
) is completely housed within the mouse R (12), which means that all the mechanical parts of the recording/playback device during recording or playback are arranged within a range approximately the same size as the tape cassette. The size of the playback device can be made extremely small, so-called cassette size.

Moreover, the lid (28) of this tape cassette can be closed after loading is completed.
8) can be closed, making it possible to make the recording/reproducing device thinner, which greatly contributes to making the recording/reproducing device even more compact.

In addition, in the tape cassette of this example, roller guides (13a) and (1
3b) and this roller guide (13a)
and (13b), the magnetic tape T is led out to the front opening of the cassette case (1), so the reel holders (8) and (9) are rotated and the tape reel (4) ) and (5) move, the magnetic tape T
There is no possibility of slackening, so there is no risk of running problems during use.

Further, in this tape cassette, roller guides (6a) and (6b) are provided on both left and right sides of the front opening of the cassette case [1].
The guide walls (39) near the roller guides (60a) and (6b) are formed so as to be set back to a greater extent than the roller guides (6a) and (6b). ) and (6
0b) The magnetic tape T can be smoothly drawn into the mouse portion (12) without the need for the magnetic tape T, and as a result, the number of mechanical parts on the recording/reproducing apparatus side can be reduced, which is more advantageous in terms of miniaturization.

In this tape cassette, the reel pressing springs (16) and (17) are connected to the spindles (10) and (10) of the reel holders (8) and (9) that hold the tape reels (4) and (5), respectively. 11) with the proximal end (16a> and (1
7a), the reel pressing springs (16) and (17) are fixed at the reel holder (8) and (7a).
9) and - legally moved, this reel holder (8) and (
The abutment points for the tape reels (4) and (5) held by the tape reels (4) and (5) held by the This does not change at all and is always pressed down with a constant force, so that the tape reels [4] and (5) always rotate stably and the tape runs smoothly.

In addition, in this example, the reel press springs (16) and (1
7) are attached to the spindles (10) and (11) of the reel holders [8] and (9), but the reel holders (8) and (
9) may be attached to other parts. That is, the reel pressing springs (16) and (17) are the tape reels (4) and (5).
It suffices to have a configuration that moves together with the robot.

Although the present invention has been applied to an 8 mm video cassette, the present invention is not limited to 8 mm video cassettes, but can also be applied to tape cassettes using a recording method using a rotating head,
For example, it goes without saying that it can be widely applied to 172-inch video cassettes and DAT (digital audio recorder) cassettes, which are currently in practical use.

〔Effect of the invention〕

As is clear from the above description, the tape cassette of the present invention maintains compatibility with standardized general tape cassettes, while further enlarging the mouse area and incorporating a head drum and a tape drive inside the mouse area. The system can be completely accommodated, and the biasing force applied to the tape reel before and after the tape reel is moved can always be set to a constant value. It has great effects.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the tape cassette of the present invention with the upper half removed, FIGS. 2 to 4 are explanatory diagrams of its operation, and FIG. 5 is an exploded perspective view of the embodiment cassette. FIG. 6 is a sectional view of the tape reel holding section, and FIG. 7 is an explanatory diagram of a conventional example. In the figure, T is a magnetic tape, (1) is a cassette case, (4)
and (5) are tape reels, (8) and (9) are reel holders, (12) are mouse parts, (16) and (17) are reel pressers, (61) are head drums, and (62) are This is a tape running system member. Substitute Hide Hitomatsu Kuma Mori 4.5...-Cheer reel 8.9...--1 reel along side 16, 17--...1 reel line tape reel &amp;
Diagram 6 of the cross section of the temple

Claims (1)

[Scope of Claims] A tape cassette having a mouth portion in front between a pair of tape reels housed in a cassette case into which a head drum or the like is inserted during recording or playback, wherein each of the pair of tape reels is movable. It is rotatably held by the reel holder, and when in use, the mouth section is enlarged by moving it together with the reel holder to the rear side of the cassette case, and the presser spring that presses the tape reel is attached to the reel holder. A tape cassette characterized in that the biasing force applied to the tape reel by the spring before and after the tape reel is attached and moved is always constant.