HK1069002B

HK1069002B - Tape cassette

Info

Publication number: HK1069002B
Application number: HK05100373.2A
Authority: HK
Inventors: 石川茂; 梅田弘幸; 藤原久重; 桥本泰文
Original assignee: 日本胜利株式会社
Priority date: 1999-06-10
Filing date: 2005-01-14
Publication date: 2006-08-11

Description

Tape cassette

This application is a divisional application entitled "tape cassette" patent application having application number 00109040.2 filed on 6/2000 by the applicant.

Technical Field

The present invention relates to a magnetic tape cartridge formed of a material having high transparency for use in detection of a tape end and detection of the presence or absence of the magnetic tape cartridge.

Background

(existing example tape cassette related to tape end detection)

The present applicant has previously proposed a magnetic tape cassette as disclosed in Japanese Utility model publication No. Sho 63-25595. Fig. 35 is a partially cutaway perspective view of the magnetic tape cartridge concerned, fig. 36 is a plan view of a lower shell portion thereof, fig. 37 is a perspective view of a portion S of fig. 36, fig. 38 is a perspective view of a portion E of fig. 36, and fig. 39 is a perspective view of a portion F of fig. 36.

In fig. 35 and 36, the cassette case 1 is composed of a lower case part 2 and an upper case part 3, and the two case parts 2, 3 are assembled in a state where joint surfaces of the both case parts are in contact with each other. A pair of tape storage compartments 4, 4 are provided in the tape cassette case 1, and reels 5 are rotatably disposed in the pair of tape storage compartments 4, 4, respectively. A magnetic tape (not shown) is wound around the pair of reels 5, and the magnetic tape is wound by the rotation of the pair of reels 5, 5. A cover lock housing portion 6 surrounding the wall portions 10d, 10e is provided at one end of the cassette case 1, and a cover lock member 7 is disposed in the cover lock housing portion 6 so as to be swingable. The cover lock member 7 locks a cover (not shown) at a closed position and displaces to an unlocked position during insertion of the magnetic tape cartridge into the recording/reproducing apparatus.

A light emitting element insertion hole 11 is provided in the center of the lower case 2 so as to be surrounded by the wall portion 10a, and a light emitting element 12 of the recording/reproducing apparatus is disposed in the light emitting element insertion hole 11 in a state where the tape cassette is mounted in the recording/reproducing apparatus. Further, a pair of photosensitive elements 13a, 13b are provided on the left and right sides of the recording and reproducing apparatus, respectively, and the pair of photosensitive elements 13a, 13b are located at outer positions on the left and right sides of the magnetic tape cartridge in a state where the magnetic tape cartridge is mounted in the recording and reproducing apparatus. In the magnetic tape cassette, sensor optical path holes 14a to 14e, 17a to 17d are provided in wall portions 10a to 10e, 16a to 16d on straight lines L1, L2 connecting the position of the light emitting element 12 and the positions of the pair of right and left photosensitive elements 13a, 13b, respectively.

Specifically, the light traveling rightward from the light emitting element 12 passes through the sensor optical path hole 14a of the right semi-cylindrical wall portion 10a constituting the light emitting element insertion hole 11 and the sensor optical path hole 14b of the wall portion 10b constituting the tape housing chamber 4, and is incident on the tape housing chamber 4. In fig. 37, the above-described respective sensor optical path holes 14a, 14b provided in the lower case portion 2 are shown. Further, a sensor optical path hole (not shown) is also provided at the same position of the upper case 3, and actually, the sensor optical path hole is constituted by both holes. The light entering the tape housing chamber 4 passes through a tape path along which the drawn tape travels, and then is transmitted to the outside of the magnetic tape cartridge through a sensor optical path hole 14c of a wall portion 10c constituting the tape housing chamber 4, a sensor optical path hole 14d of a wall portion 10d constituting the cover lock housing portion 6, and a sensor optical path hole 14e of a wall portion 10e on the side surface of the magnetic tape cartridge (common to the wall portion constituting the cover lock housing portion 6), and reaches the photosensitive element 13 a. In fig. 38, the above-described respective sensor optical path holes 14c to 14e provided in the lower case portion 2 are shown. Further, a sensor optical path hole (except for the sensor optical path hole in the side wall of the tape cartridge) is also provided at the same position in the upper case 3, and actually, the sensor optical path hole is formed by both holes.

The light proceeding leftward from the light emitting element 12 passes through the sensor optical path hole 17a of the left semi-cylindrical wall 16a constituting the light emitting element insertion hole 11 and the sensor optical path hole 17b of the wall 16b constituting the tape housing chamber 4, and is incident on the tape housing chamber 4. In fig. 37, the above-described sensor optical path holes 17a, 17b provided in the lower case portion 2 are shown. Further, a sensor optical path hole (not shown) is also provided at the same position of the upper case 3, and actually, the sensor optical path hole is constituted by both holes. The light entering the tape housing chamber 4 passes through a tape path on which the drawn tape runs, and then is transmitted to the outside of the magnetic tape cartridge through a hole 17c for sensor optical path constituting a wall 16c of the tape housing chamber 4, a hole 18a for sensor optical path of a tape spacer 18 as a transparent member, and a hole 17d for sensor optical path of a wall 16d on the side surface of the magnetic tape cartridge, and reaches the photosensitive element 13 b. Fig. 39 shows the sensor optical path holes 17c and 17d provided in the lower case 2 and the sensor optical path hole 18a of the tape spacer 18. Further, a sensor optical path hole (except for the sensor optical path hole in the side wall of the tape cartridge) is also provided at the same position in the upper case 3, and actually, the sensor optical path hole is formed by both holes.

The wall portions 10c to 10e, 16a to 16d and the like constituting the sensor optical path holes 14c to 14e, 15a to 15d on the optical path after the light from the light emitting element 12 exits from the tape housing chamber 4 are colored in colors having low light reflectance. In fig. 38 and 39, the colored position of the lower case portion 2 is indicated by hatching, and the corresponding position of the upper case portion 3 is also colored.

In the above configuration, the light traveling rightward from the light emitting element 12 passes through the sensor optical path holes 14a and 14b and reaches the tape path, and if the tape on the tape path is a magnetic recording layer tape portion, the light does not reach the photosensitive element 13a because it is opaque, or if the tape on the tape path is a highly translucent tape portion, the light passes through the sensor optical path holes 14c to 14e and reaches the photosensitive element 13 a. The light advancing leftward from the light emitting element 12 passes through the sensor optical path holes 17a, 17b and reaches the tape path, and if the tape on the tape path is a magnetic recording layer tape portion, the light does not reach the photosensitive element 13b because of the opacity, or if the tape on the tape path is a tape portion having high optical transparency, the light passes through the sensor optical path holes 17c, 18a, 13d and reaches the photosensitive element 13 b. In this way, when the tape on the tape path is the magnetic recording layer tape section and the tape guide section, the tape end on the tape winding side and the tape feeding side is detected by the difference in output voltage between the photosensitive elements 13a and 13 b.

Therefore, of the light from the light emitting element 12, not only the component directed toward the photosensitive elements 13a, 13b but also the light of other components are reflected by the flange of the reel 5 and the inner surface of the cartridge case 1, and the like, and do not reach the photosensitive elements 13a, 13b through the tape path. Further, external light enters the tape cartridge case 1 through a window on the upper surface of the tape housing chamber 4 of the tape cartridge, and the incident light is reflected by the flange of the reel 5, the inner surface of the tape cartridge case 1, and the like, and does not reach the photosensitive elements 13a and 13b through the tape path.

However, in the case where the cartridge case 1 itself is made of a material having a low light reflectance such as black, the amount of light reaching the photosensitive elements is extremely low, and there is no risk of malfunction of the photosensitive elements 13a and 13 b. Therefore, there is a demand for the cassette case 1 itself to be made of a material having high light reflectance and high transparency, and in this case, the amount of light reaching the photosensitive elements 13a and 13b is high, which causes a problem.

However, in the above conventional example, since the portions close to the photosensitive elements 13a and 13b are colored in a color having a low light reflectance, the unnecessary light can be sufficiently attenuated at the positions, and malfunction due to the unnecessary light can be prevented. That is, it is possible to manufacture a colorful tape cassette without considering the color of the tape cassette case 1.

(magnetic tape cartridges relating to detection of absence of magnetic tape cartridges)

The magnetic tape cartridge can be handled by various devices in addition to the recording and reproducing device. For example, as an example thereof, there is a cartridge changer for a duplicator service, and fig. 40 and 41 show an example of use of the cartridge changer. In fig. 40 and 41, a recording and reproducing apparatus 101 is a reproducing apparatus having two cartridge driving sections and the like, and a cartridge changer 103 is attached to one cartridge insertion side of the recording and reproducing apparatus 101 through a joint section 102.

The cassette changer 103 has a cassette holder 105 slidably disposed on the changer body 104, and the cassette holder 105 moves between a cassette reference position and a cassette transition position of the recording and reproducing apparatus 101. A pair of tape cartridge stoppers 107, 107 for holding the tape cartridge 106 at a tape cartridge placing position are provided above the tape cartridge holder 105, and the pair of tape cartridge stoppers 107, 107 are moved in directions (arrow directions in fig. 40 (B)) separating from each other, whereby the tape cartridge 106 is guided onto the reel 108 while being dropped onto the tape cartridge holder 105.

The changer body 104 is provided with a cartridge pressing lever 110 that slides along a guide rail 109, and the cartridge pressing lever 110 can move the cartridge 106 from the cartridge reference position of the cartridge holder 105 to the cartridge ejecting position (cartridge position) of the magazine 111 by pressing the side surface of the cartridge 106. The magazine 111 is provided on the lateral side of the cartridge tray 105, and the changer body 104 is provided with a cartridge non-presence detecting device 112 for detecting whether or not the cartridge 106 is present at the cartridge ejecting position on the magazine 111.

The cartridge non-detection device 112 includes a light-emitting portion 112a and a light-receiving portion 112b that receives the detection light from the light-emitting portion 112a, and an optical path CC of the detection light reaching the light-receiving portion 112b from the light-emitting portion 112a is set to pass through a cartridge discharge position, which is a cartridge position.

The operation of the above-described structure will be described below. As shown by hatching in fig. 40(a), (B), the cartridge 106 is placed at the cartridge placing position. When the mode is changed to the start mode, the pair of cartridge stoppers 107 and 107 move to positions spaced apart from each other, and the cartridge 106 drops to the cartridge reference position on the cartridge tray 105. Subsequently, the cartridge tray 105 is moved to a cartridge transition position of the recording/reproducing apparatus 101, and the cartridge 106 is loaded into the recording/reproducing apparatus 101 to start copying. When the copying is finished, the magnetic tape cartridge 106 is ejected from the recording and reproducing apparatus 101 and returned to the cartridge tray 105. Subsequently, the cartridge holder 105 is moved to the cartridge reference position, and the cartridge 106 at the cartridge reference position is pressed by the cartridge pressing rod 110 and ejected to the cartridge ejecting position (the state of fig. 41(a), (B)).

When the tape cartridge 106 is arranged at the cartridge placement position, the start mode is selected, and the copy is performed by the same operation procedure as described above. In this way, when the user removes the tape cartridge 106 from the tape cartridge ejecting position after the copying is completed, the detection light from the light emitting unit 112a reaches the light receiving unit 112b without being blocked by the tape cartridge 106, and therefore the tape cartridge non-detection device 112 detects that the tape cartridge 106 is not in the tape cartridge ejecting position, and then ejects the tape cartridge 106 after the copying to the tape cartridge ejecting position through the same operation procedure as described above. Further, in the case where the user does not remove the tape cartridge 106 from the tape cartridge ejecting position after the copying, the detection light from the light emitting portion 112a is blocked by the tape cartridge 106 and does not reach the light receiving portion 112b, and therefore, the tape cartridge non-detecting device 112 detects that the tape cartridge 106 is at the tape cartridge ejecting position, and then, even if the tape cartridge 106 is present after the copying, the tape cartridge is not ejected to the tape cartridge ejecting position.

(tape cartridge associated with tape end detection)

However, in the magnetic tape cartridge of the above conventional example, since coloring is required at the position of the magnetic tape cartridge case 1 near the photosensitive elements 13a, 13b, the processing step thereof needs to go through a very complicated coloring step, and therefore, the production efficiency is low, and there is a problem that mass production cannot be coped with.

Further, there is a demand for the cassette case 1 itself to be made of a material having high transparency, and in this case, when the color is colored in a color having low light reflectance, there is a problem that the color of the colored portion is different from the originally intended color.

(tape cartridges unrelated to detection tape cartridges)

There is also a demand for forming the cartridge case itself of the magnetic tape cartridge 106 from a material having high transparency, and when the magnetic tape cartridge 106 is formed in this manner, there is a possibility that the magnetic tape cartridge non-detecting device 112 may erroneously detect the magnetic tape cartridge. That is, even when the tape cassette 106 is at the tape cassette ejecting position, the detection light from the light emitting unit 112a passes through the tape cassette case and reaches the light receiving unit 112b, and the absence of the tape cassette is erroneously detected. When such erroneous detection is performed, the next cartridge 106 is fed to the cartridge discharge position regardless of whether the cartridge 106 is in the cartridge discharge position, and therefore, the leading cartridge 106 falls from the magazine 111 and is damaged, and if a fall-preventing wall is present in the magazine 111, a high load is applied to the cartridge push rod 110, and the cartridge changer 103 and the like are damaged.

Disclosure of Invention

Accordingly, in order to solve the above-described problems, an object of the present invention is to provide a tape cassette which can prevent erroneous detection of a tape end regardless of the material (color, transparency, and reflectance) of a tape cassette case, and can maintain the color originally intended as the color of the tape cassette case as much as possible without lowering the production efficiency when a tape cassette case main body is made of a material having high transparency.

In order to solve the above problems, an object of the present invention is to provide a magnetic tape cartridge capable of preventing a detection error of the magnetic tape cartridge even if a case of the magnetic tape cartridge is formed of a material having high transparency.

To this end, the present invention provides a magnetic tape cartridge comprising: a pair of tape storage chambers; a pair of reels on which magnetic tapes are wound, the magnetic tapes being accommodated in the pair of tape accommodating chambers, the magnetic tapes each including a magnetic tape portion of a magnetic recording layer and highly light-transmissive tape portions attached to both ends of the magnetic tapes; a first wall portion that forms an insertion hole into which a first light emitting element of a recording-reproducing apparatus is inserted when the magnetic tape cartridge is loaded into the recording-reproducing apparatus, the first wall portion having a first hole that can guide light emitted from the first light emitting element out of the insertion hole; a second wall portion forming a part of the tape housing chamber and having a second hole for guiding the light emitted from the first light emitting element into the tape housing chamber; a third wall portion forming another part of the tape housing chamber and having a third hole for guiding the light guided from the first light emitting element into the tape housing chamber out of the tape housing chamber; a fourth wall portion forming a part of a cover lock member accommodating chamber for accommodating a cover lock member for locking a cover of the magnetic tape cartridge, the fourth wall portion having a fourth hole for guiding light guided out of the magnetic tape accommodating chamber from the first light emitting element into the cover lock member accommodating chamber; a fifth wall portion forming another part of the cover lock member accommodating chamber and having a fifth hole for guiding the light guided from the first light emitting element into the cover lock member accommodating chamber out of the magnetic tape cartridge and then onto the first photosensitive element of the recording and reproducing apparatus; a first light shielding member provided in the vicinity of at least one of the third wall portion and the fourth wall portion, the first light shielding member being formed from each of the tape storage compartments, the first light shielding member having a hole through which light emitted from the first light emitting element can pass; and a second light shielding member provided in the vicinity of at least one of the third wall portion and the fourth wall portion, the second light shielding member being formed from each of the tape storage compartments, the second light shielding member blocking light emitted from a second light emitting element of the recording/reproducing apparatus for detecting the absence of the cartridge, so as to prevent the light from the second light emitting element from reaching a second photosensitive element of the recording/reproducing apparatus.

The present invention also provides a tape cassette comprising: a pair of tape storage chambers having a tape supply side and a tape take-up side; a pair of reels on which magnetic tapes are wound, the magnetic tapes being accommodated in the pair of tape accommodating chambers, the magnetic tapes each including a magnetic tape portion of a magnetic recording layer and highly transparent tape portions attached to both ends of the magnetic tapes; a first wall portion that forms an insertion hole into which a light emitting element of a recording and reproducing apparatus is inserted when the magnetic tape cartridge is loaded into the recording and reproducing apparatus, the first wall portion having a first hole that guides light emitted from the light emitting element out of the insertion hole; a second wall portion forming a part of the tape supply-side tape housing chamber and having a second hole for guiding the light emitted from the light emitting element into the tape supply-side tape housing chamber; a third wall portion that forms another part of the tape supply-side tape housing chamber and has a third hole for guiding light guided from the light emitting element into the tape supply-side tape housing chamber out of the tape supply-side tape housing chamber; a fourth wall portion having a fourth hole for guiding the light emitted from the light emitting element out of the magnetic tape cartridge and then guiding the light to the photosensitive element of the recording and reproducing apparatus; and a light shielding member provided in the vicinity of the fourth wall portion, the light shielding member being a flat thin plate-like member formed from the fourth wall portion, the member having a hole through which light emitted from the light emitting element can pass.

In the above magnetic tape cartridge, the shutter member is provided: the light path center connecting the position of the light emitting element and the position of the light sensing element with a straight line has a width of not less than 1mm on the left and right sides, respectively, and covers the entire height of the fourth wall portion.

Drawings

These and other objects, advantages and features of the present invention will be further explained by the description of the embodiments of the present invention in conjunction with the accompanying drawings. In these drawings:

FIG. 1 shows a first embodiment of the present invention;

FIG. 1(A) is a plan view of the lower housing portion;

fig. 1(B) is a perspective view of a portion E of fig. 1 (a);

FIG. 2 is a schematic longitudinal sectional view of a magnetic tape cartridge according to a first embodiment of the present invention;

fig. 3 is a main portion perspective view of a lower case portion of a second embodiment of the present invention;

fig. 4 is a main portion perspective view of a lower case portion of a third embodiment of the present invention;

fig. 5 is a main portion perspective view of a lower case portion of a fourth embodiment of the present invention;

FIG. 6 shows a fifth embodiment of the present invention, which is a main portion perspective view of a lower casing portion;

FIG. 7 shows a fifth embodiment of the present invention, which is a perspective view of a shade support;

fig. 8 shows a sixth embodiment of the invention, which is a main portion perspective view of a lower housing portion;

FIG. 9 shows a seventh embodiment of the invention;

FIG. 9(A) is a side view of the lid latch component;

FIG. 9(B) is a front view of the lid lock component;

fig. 10(a) is a diagram showing sensor output characteristics when the respective widths (light shielding range widths) of the left and right light shielding portions are changed in the first to sixth embodiments using a configuration in which the color of the cartridge case is colorless (transparent);

fig. 10B is a view showing respective left and right widths (light shielding range widths) of the light shielding portion;

fig. 11 is a list of malfunction evaluation results in the first and second embodiments and the respective comparative examples;

FIG. 12 is a schematic longitudinal sectional view of a magnetic tape cartridge according to an eighth embodiment of the present invention;

fig. 13 shows an eighth embodiment of the present invention, which is a perspective view of a main portion of a lower casing portion (corresponding to portion F of fig. 1 (a));

fig. 14 shows a ninth embodiment of the invention, which is a main part perspective view of a lower casing part;

fig. 15 shows a tenth embodiment of the invention, which is a main portion perspective view of a lower housing portion;

FIG. 16 is a perspective view of a tape shim according to a tenth embodiment of the present invention;

fig. 17 shows an eleventh embodiment of the invention, which is a main portion perspective view of a lower casing portion;

fig. 18 shows a twelfth embodiment of the invention, which is a main portion perspective view of a lower casing portion;

fig. 19 is a list of malfunction evaluation results in the eighth to eleventh embodiments and the respective comparative examples;

FIG. 20 is a schematic cross-sectional view of a magnetic tape cartridge according to a thirteenth embodiment of the present invention;

FIG. 21 shows a fourteenth embodiment of the invention;

fig. 21(a) is a plan view of the upper face of the cartridge case with only the magnetic tape cartridge removed;

FIG. 21(B) is a rear view of the magnetic tape cartridge;

FIG. 21(C) is a side view of the magnetic tape cartridge;

FIG. 22 shows a fourteenth embodiment of the present invention, which is a partially enlarged view of the MM portion of FIG. 21 (A);

fig. 23 shows a fourteenth embodiment of the present invention, showing the optical path of the detection light incident on the prism portion of the side surface portion;

fig. 24 shows a fourteenth embodiment of the present invention, showing the optical path of the detection light incident on the prism portion of the rear surface portion;

fig. 25 shows a fifteenth embodiment of the present invention, which is a view showing a prism portion disposed in a portion shown in a partially enlarged view of the MM portion in fig. 21 (a);

FIG. 26 shows a sixteenth embodiment of the invention;

fig. 26(a) is a plan view of the upper face of the cartridge case with only the cartridge removed;

FIG. 26(B) is a rear view of the magnetic tape cartridge;

FIG. 26(C) is a side view of the magnetic tape cartridge;

fig. 27 shows a sixteenth embodiment of the present invention, which is a partial enlarged view of the portion N of fig. 26 (C);

fig. 28 shows a sixteenth embodiment of the invention, which is a diagram showing the optical path of detection light incident on the prism portion of the bottom surface portion;

FIG. 29 shows a seventeenth embodiment of the invention;

fig. 29(a) is a plan view of the upper face of the cartridge case with only the cartridge removed;

FIG. 29(B) is a rear view of the magnetic tape cartridge;

FIG. 29(C) is a side view of the magnetic tape cartridge;

FIG. 30 shows an eighteenth embodiment of the invention, in partial plan view, on the upper side of the cartridge shell with the cartridge removed;

FIG. 31 shows an eighteenth embodiment of the invention, which is a perspective view showing a main part before a light shielding member is attached;

FIG. 32 is a perspective view showing a main part in a state where a light shielding member is attached, showing an eighteenth embodiment of the present invention;

fig. 33 is a plan view showing a nineteenth embodiment of the present invention, with only the upper face of the cartridge case of the magnetic tape cartridge removed;

FIG. 34 shows a nineteenth embodiment of the invention;

fig. 34(a) is a schematic view of the periphery of the notched portion for the optical path of the cartridge case of the magnetic tape cartridge;

FIG. 34(B) is a view showing the optical path of the tape end detection light when a prism portion is provided;

FIG. 34(C) is a view showing the optical path of the tape end detection light when no prism portion is present;

FIG. 35 is a partial cutaway perspective view of a magnetic tape cartridge showing a prior art example relating to tape end detection;

FIG. 36 is a plan view of a lower casing part showing a conventional example relating to tape end detection;

FIG. 37 is a perspective view of a portion S of FIG. 36 showing a conventional example relating to tape end detection;

FIG. 38 is a perspective view of a portion E of FIG. 36 showing a conventional example relating to tape end detection;

FIG. 39 is a perspective view of part F of FIG. 36 showing a conventional example relating to tape end detection;

FIG. 40A is a plan view showing a state of use of a conventional cassette changer;

FIG. 40(B) is a front view thereof;

FIG. 41(A) is a plan view showing a state of use of a conventional cassette changer;

fig. 41(B) is a front view thereof.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

Embodiments of the present invention are described below with reference to the drawings.

(embodiments of tape cartridges relating to tape end detection)

The first to seventh embodiments describe configurations for detecting a tape end on a winding side (tape winding side), the eighth to twelfth embodiments describe configurations for detecting a tape end on a tape feeding side (tape feeding side), and the thirteenth embodiment describes configurations for detecting tape ends on both the winding side and the tape feeding side, that is, configurations corresponding to both the winding side and the tape feeding side. The following description will be made in order.

Fig. 1 and 2 show a first embodiment of the present invention, fig. 1(a) is a plan view of a lower case portion 2, fig. 1(B) is a perspective view of a portion E of fig. 1(a), and fig. 2 is a schematic longitudinal sectional view of a magnetic tape cassette. In fig. 1 and 2, the first embodiment is compared with the conventional example relating to the tape end detection, and the same components are not described in order to avoid redundant description, and only different components will be described. In fig. 1 and 2, the same components as those of the conventional example relating to the tape end detection are denoted by the same reference numerals for easy understanding. As are the subsequent figures.

That is, in the first embodiment, as in the conventional example, the portion near the light receiving element 13a is not colored with a color having a low light reflectance, and as shown in fig. 1(B), the light blocking material 20 as the light blocking portion 15 is attached to the periphery of the sensor optical path hole 14c after the light from the light emitting element 12 passes through the tape housing chamber 4 on the right side (tape winding side). The light shielding material 20 is made of a material having a light shielding effect and a color, and a sensor optical path hole 21 is provided at a position corresponding to the sensor optical path hole 14 c.

The light screening material 20 is provided: the width D of about 1mm or more extends from the center of the optical path connecting the position of the light emitting element 12 and the position of the light receiving element 13a by a straight line L1 to the left and right, and extends over the entire height of the wall portion 10 c. The reason why the left and right widths D are each about 1mm or more will be described in detail below.

Although fig. 1B shows only the lower case 2, a wall portion (not shown) is provided at a position opposite to the upper case 3, and the entire height of the wall portion 10c is a height at which the lower case 2 and the upper case 3 are combined. In the following drawings, only the lower case 2 is shown, but a wall portion (not shown) is also provided at a position facing the upper case 3, and the same processing as that of the lower case is performed when the processing is performed. Further, the light shielding portion 15 of the following second embodiment and subsequent embodiments is provided: the width D of about 1mm or more extends from the center of the optical path connecting the position of the light emitting element 12 and the position of the light receiving element 13a by a straight line L1 to the left and right, and extends over the entire height of the wall portion 10 c.

In the above configuration, among the light from the light emitting element 12, the light 22 incident on the photosensitive element 13a passes through the sensor optical path holes 14a and 14b and reaches the tape path, and if the magnetic tape T on the tape path is a magnetic recording layer magnetic tape portion, the light does not reach the photosensitive element 13a because it is opaque, or if the magnetic tape T on the tape path is a tape portion having high optical transparency, the light passes through the sensor optical path holes 14c to 14e and reaches the photosensitive element 13 a.

In the light emitting element 12, unnecessary light 23 not directed toward the photosensitive element 13a and unnecessary light 23 entering the cartridge case 1 from an upper surface window of the tape housing chamber 4 of the tape cartridge are reflected by the upper and lower flanges 5a, 5b of the reel 5 and the inner surface of the cartridge case 1, and are directed toward the photosensitive element 13a without passing through the tape path. Most of the unnecessary light 23 that may reach the photosensitive element 13a strikes the light-shielding material 20 and is shielded thereby, and therefore, the proportion of the unnecessary light that reaches the photosensitive element 13a is very low.

Thus, the malfunction of tape end detection can be prevented regardless of the material (color, transparency, reflectivity) of the tape cassette case 1. In addition, since the light shielding material 20 can be attached only to the wall portion 10c in the manufacture of the magnetic tape cassette, the production efficiency is not so low as in the conventional example. Further, the light shielding material 20 may be pasted only on one wall portion 10c and on the wall portion 10c which is not the outer surface of the cartridge case 1, and therefore, in the case where the cartridge case main body is made of a material having high transparency, the originally intended color can be maintained as much as possible as the color of the cartridge case 1.

Fig. 3 is a main portion perspective view of a lower case portion of a second embodiment of the present invention (corresponding to fig. 1 (B)). In fig. 3, in the second embodiment, the light shielding material 20 as the light shielding portion 15 is attached to the periphery of the next sensor optical path hole 14d, not after the light from the light emitting element 12 passes through the tape housing chamber 4. In fig. 3, the light shielding material 20 is shown as being stuck to the wall portion 10d on the wall portion 10c side, but may be stuck to the wall portion 10d on the wall portion 10e side. The other configurations are the same as those of the first embodiment, and therefore, the description thereof is omitted.

In this second embodiment, it may be desirable to have the same action and effect as those of the first embodiment described above.

Further, as a modification of the first and second embodiments, the light shielding material 20 may be attached to the periphery of the sensor optical path hole 14c and the periphery of the next sensor optical path hole 14d after the light from the light emitting element 12 passes through the tape housing chamber 4. According to this modification, since the light shielding effect against unnecessary light can be further enhanced, it is possible to more reliably prevent a malfunction in the tape end detection of the magnetic tape T. However, since the positions where the light shielding material 20 is attached are two, although it is disadvantageous in terms of production efficiency, it still has a significant effect as compared with the conventional example.

Fig. 4 is a main portion perspective view of the lower case portion 2 of the third embodiment of the present invention (corresponding to fig. 1 (B)). In fig. 4, in this third embodiment, the light shielding portion 15 is provided around the sensor optical path hole 14c after the light from the light emitting element 12 passes through the tape housing chamber 4, but this light shielding portion 15 may be constituted by forming the body of the wall portion 10c with a two-color light shielding material in the molding process of the tape cassette housing 1. In fig. 4, the position of the light shielding material is indicated by hatching.

In this third embodiment, as in the first embodiment described above, the malfunction of tape end detection can be prevented regardless of the material (color, transparency, reflectance) of the tape cassette case 1. In addition, when the cartridge case 1 main body is made of a material having high transparency, the color of the cartridge case 1 can be maintained as much as possible. Further, since the wall portion 10c can be formed in two colors in the process of manufacturing the magnetic tape cassette, the production efficiency does not become extremely low as in the conventional case.

Fig. 5 is a main portion perspective view of a lower case portion 2 of a fourth embodiment of the present invention (corresponding to fig. 1 (B)). In fig. 5, the fourth embodiment is different from the third embodiment in that light from the light emitting element 12 is not transmitted through the tape housing chamber 4, but is formed into two colors in the next wall 10 d. The other structures are the same as those of the third embodiment, and the description thereof is omitted.

In this fourth embodiment, it is desirable to have the same action and effect as those of the above-described third embodiment.

Further, as a modification of the third and fourth embodiments, the wall portion 10c and the next wall portion 10d after the light from the light emitting element 12 passes through the tape housing chamber 4 may be formed simultaneously with two-color materials. According to this modification, since the light blocking effect of unnecessary light can be further improved, it is possible to more reliably prevent malfunction of the tape end detection. Further, although two locations are provided for two-color formation, the production efficiency is the same as that of the third and fourth embodiments, and is not disadvantageous.

Fig. 6 and 7 show a fifth embodiment of the present invention, fig. 6 is a perspective view of a main part of the lower case portion 2 (corresponding to fig. 1 (B)), and fig. 7 is a perspective view of a light shielding bracket. In fig. 6, in the fifth embodiment, a light shielding portion 15 is provided in a wall portion 10c after light from a light emitting element 12 passes through a tape housing chamber 4, and the light shielding portion 15 is configured by attaching a light shielding holder 23 shown in fig. 7 to the wall portion 10 c.

That is, the areas indicated by the vertical hatching in fig. 6 are cut out without providing the sensor optical path holes in the wall portion 10c of each of the above embodiments. The light shielding bracket 23 shown in fig. 7 is attached to the wall portion 10c formed in the lower portion by locking the locking piece 23 b. As shown in fig. 7, the light shielding holder 23 is formed of a material and a color having a light shielding effect, and a sensor optical path hole 23a is provided at a position corresponding to the sensor optical path hole 14c, and a pair of locking pieces 23b, 23b locked to the upper and lower wall portions 10c (the upper case portion side is not shown) are formed to be integrally protruded.

In the fifth embodiment, as in the first embodiment, it is possible to prevent erroneous detection of the tape end regardless of the material (color, transparency, reflectance) of the tape cassette case 1, and to maintain the originally intended color as much as possible as the color of the tape cassette case 1 when the tape cassette case 1 main body is made of a material having high transparency. Further, since the light shielding bracket 23 can be attached to the wall portion 10c in the process of manufacturing the magnetic tape cassette, the production efficiency does not become extremely low as in the conventional example.

Fig. 8 shows a sixth embodiment of the present invention, and fig. 8 is a perspective view of a main portion of the lower case portion 2 (corresponding to fig. 1 (B)). In fig. 8, in the sixth embodiment, a light shielding portion 15 is provided on the next wall portion 10d after light from the light emitting element 12 passes through the tape housing chamber 4, and the light shielding portion 15 is configured by attaching a light shielding holder 23 shown in fig. 7 to the wall portion 10 d. The specific configuration is the same as that of the fifth embodiment, and thus the description thereof is omitted.

In this sixth embodiment, it is desirable to have the same action and effect as those of the above-described fifth embodiment.

Further, as a modification of the fifth and sixth embodiments, the light shielding holder 23 may be attached to both the wall portion 10c and the next wall portion 10d after the light from the light emitting element 12 passes through the tape housing chamber 4. According to this modification, since the light shielding effect against unnecessary light can be further improved, it is possible to more reliably prevent malfunction of the tape end detection. However, since the two positions for attaching the light shielding bracket 23 are provided, although there is a disadvantage in terms of production efficiency, it is still significantly effective as compared with the conventional example.

FIG. 9 shows a seventh embodiment of the invention; fig. 9(a) is a side view of the cover lock member 25; fig. 9(B) is a front view of the cover lock member 25. In fig. 9 a and 9B, the cover lock member 25 is disposed in the cover lock accommodating portion 6 (shown in fig. 1) as shown in fig. 1 a. The cover lock member 25 is made of a material having a light shielding effect and is colored, and includes a flat plate portion 25a, a rotation support portion 25b fixed to the upper end thereof, a pressed portion 25c protruding to the lower end portion of the flat plate portion 25a, a locking claw portion 25d of a lock cover (not shown), and a cylindrical protrusion portion 25e protruding to the opposite side of the pressed portion 25c and the locking claw portion 25d at the substantially center of the flat plate portion 25 a.

A sensor optical path hole 26 is provided in the cylindrical protrusion 25e, and the sensor optical path hole 26 is preferably set in the cover lock accommodating portion 6 so as not to interfere with it. The cylindrical protrusion 25e is positioned in a state of being inclined downward at the lid lock position (the position of fig. 9(a) and (B)). When the pressed portion 25c is pressed during the insertion of the magnetic tape cartridge, the cylindrical protrusion 25e is rotated in the arrow direction of fig. 9(B) with the rotation support portion 25B as a fulcrum to be positioned at the unlock position. In the unlock position, the cylindrical protrusion 25e is positioned in the horizontal direction, and the sensor optical path hole 26 of the cylindrical protrusion 25e is disposed on a straight line L1 connecting the position of the light emitting element 12 and the position of the light receiving element 13 a.

According to the seventh embodiment, the light that is directly incident on the photosensitive element 13a among the light from the light emitting element 12 passes through the tape housing chamber 4 (as shown in fig. 1 a), enters the cover lock housing portion 6 (as shown in fig. 1 a), and enters the sensor optical path hole 26 of the cylindrical protrusion portion 25e, and the incident light is emitted without hitting the inner surface of the sensor optical path hole 26, but passes through the sensor optical path hole 14e and reaches the photosensitive element 13 a. However, the unnecessary light is generally not directed toward the photosensitive element 13a, but is incident on the sensor optical path hole 26 of the cylindrical protrusion 25e, reaches the inner surface of the sensor optical path hole 26 having the length M, and is blocked by the absorption effect. Thus, in the seventh embodiment, by processing only the cover lock member 25, it is possible to prevent erroneous operation of tape end detection regardless of the material (color, transparency, reflectance) of the tape cassette case 1, to adapt to mass production without lowering the production efficiency, and to maintain the originally intended color as much as possible as the color of the tape cassette case 1 when the tape cassette case main body is made of a material having high transparency.

The seventh embodiment has the same effects as those of the first to sixth embodiments, but may be combined with the first to sixth embodiments to further enhance the effect of preventing malfunction.

Further, in the seventh embodiment, the cover lock member 25 main body is constituted by a material and a color having a light shielding effect, but the cylindrical protrusion portion 25e may be constituted by only a material and a color having a light shielding effect. Further, as in the seventh embodiment, in the case where the cover locking member 25 main body is made of a material and a color having a light shielding effect, light reaching the flat plate portion 25a or the like of the cover locking member 25 among unnecessary light is shielded by its absorption effect, and therefore, the light shielding effect for the unnecessary light can be improved.

Fig. 10(a) is a graph of sensor output characteristics when the respective widths (light shielding range widths) D on the left and right of the light shielding portion are changed using a material in which the color of the cartridge case 1 is colorless (transparent) in the first to sixth embodiments; fig. 10B shows the respective left and right widths (light shielding range widths) D of the light shielding portions. The hatched lines in fig. 10(B) indicate the regions of the light shielding portions 15 in the first to sixth embodiments. As described above, the respective left and right widths D of the light shielding portion 15 are widths D from the left and right of the center of the optical path connecting the position of the light emitting element 12 and the position of the light receiving element 13a by the straight line L1, and if the widths D are set to 1mm or more, a desired light shielding effect can be obtained, which will be described below.

In tape end detection, the threshold value is around 3V, and regardless of the detection state of the magnetic recording layer magnetic tape unit, if the sensor output voltage is 3V or more, a malfunction occurs, and if it is below, it is normal, and no malfunction occurs.

As shown in fig. 10(a), when the light shielding range width is zero and the light shielding portion 15 is not provided at all around the sensor optical path hole 14c (or 14d), the sensor output voltage is 5V, and malfunction occurs. When the light shielding portion 15 is provided around the sensor optical path hole 14c (or 14D) and the width D thereof is gradually increased, the sensor output voltage gradually decreases. When the width D of each of the left and right sides of the light shielding portion 15 is about 1mm, the sensor output voltage is 3V or less, and when the width D of each of the left and right sides of the light shielding portion 15 is 2mm or more, the sensor output voltage is reduced to 1V or less. This means that the amount of the unnecessary light reaching the photosensitive element 13a is reduced because the unnecessary light is shielded by the light shielding portion 15, and the amount of the unnecessary light reaching the photosensitive element 13a mainly depends on the respective left and right widths D of the light shielding portion 15.

Although there are the upper and lower reflected lights reflected by the flange 5a of the reel 5 and the left and right reflected lights reflected by the wall portion of the cartridge case 1 as unnecessary lights reaching the photosensitive element 13a, the probability that the upper and lower reflected lights reach the photosensitive element 13a is very high, and the upper and lower reflected lights are shielded by the light shielding portion 15. That is, light can be effectively blocked without blocking all of the periphery of the sensor optical path hole 14c (or 14 d).

As described above, as is clear from fig. 10a, even if the lateral side of the sensor optical path hole 14c (or 14D) is not shielded from light, if the width D of each of the left and right sides of the light shielding portion 15 is set to 1mm or more, the sensor output of 3V or less can be maintained without causing malfunction.

Fig. 11 is a table showing a list of malfunction evaluation results in the first and second embodiments and the respective comparative examples. In comparative example 1, a light shielding portion is provided around the sensor optical path hole 14a of the wall portion 10a on the side where light from the light emitting element 12 enters the tape housing chamber 4, and in comparative example 2, a light shielding portion is provided around the sensor optical path hole 14b of the wall portion 10b on the side where light from the light emitting element 12 enters the tape housing chamber 4. In comparative example 3, a light shielding portion is provided around the sensor optical path hole 14e of the last wall portion 10e after the light from the light emitting element 12 passes through the tape housing chamber 4.

The color of the cartridge case of sample a was colorless (transparent); the color of the cartridge case of sample B was hazy (translucent); the cartridge case for sample C was red (opaque) in color; the cartridge case of sample D was black (opaque) in color. The measurement apparatus used a VTR generally available on the market.

The markers for the evaluation results were: the "Δ" indicates that there is no problem in the operation of the commercial VTR, the "Δ" indicates that the detection voltage of the sensor is large and there is a possibility of malfunction in the commercial VTR, and the "x" indicates that malfunction often occurs in the commercial VTR. As shown in fig. 11, in the embodiment of the present invention, the erroneous operation of the tape end detection can be prevented regardless of the material (color, transparency, reflectivity) of the tape cassette case 1.

Fig. 12 and 13 show an eighth embodiment of the present invention, fig. 12 is a schematic longitudinal sectional view of a magnetic tape cartridge, and fig. 13 is a perspective view of a main portion of a lower casing portion (corresponding to portion F in fig. 1 a). In fig. 12 and 13, the eighth embodiment is compared with the conventional example, and the same configuration will be omitted to avoid redundancy of description, and only different configurations will be described.

That is, in the eighth embodiment, as in the conventional example, the portion near the light receiving element 13 is not colored in a color having a low light reflectance, and as shown in fig. 13, the light shielding portion 15 is provided around the sensor optical path hole 17c of the wall portion 16c after the light from the light emitting element 12 passes through the tape housing chamber 4 on the left side (the feeding side). The light shielding portion 15 is formed by attaching a light shielding member formed of a material and a color having a light shielding effect to the wall portion 16c as in the first embodiment, or by forming a two-color wall portion 16c body with a light shielding material in the molding process of the tape cassette housing 1 as in the third embodiment, or by attaching a light shielding bracket to the wall portion 16c as in the fifth embodiment.

Further, in the tape end detection on the tape supply side, the light shielding portion 15 is provided with: the widths D from the left and right of the optical path center connecting the position of the light emitting element 12 and the position of the light receiving element 13b by the straight line L2 are about 1mm or more, respectively, and span the entire height of the wall portion 16 c. The same applies to the ninth, tenth, and twelfth embodiments described later. The reason why the width of each of the left and right sides is set to about 1mm or more is the reason described above.

In the above configuration, the light 22 directly incident on the photosensitive element 13b among the light from the light emitting element 12 passes through the sensor optical path holes 17a, 17b and reaches the tape path, and if the magnetic tape T on the tape path is a magnetic recording layer magnetic tape portion, the light does not reach the photosensitive element 13b because of the opacity, or if the magnetic tape T on the tape path is a tape guide portion having high optical transparency, the light passes through the sensor optical path holes 17c, 18a, 17d and reaches the photosensitive element 13 b.

The unnecessary light 23 in the light emitting element 12 which is not directed toward the light receiving element 13b and the unnecessary light 23 which enters the cartridge case 1 from the upper window of the tape housing chamber 4 of the cartridge are reflected by the upper and lower flanges 5a, 5b of the reel 5 and the inner surface of the cartridge case 1, and are directed toward the light receiving element 13a without passing through the tape path. Most of the unnecessary light 23 that reaches the photosensitive element 13a may strike and be blocked by the light blocking portion 15, and therefore the proportion of the unnecessary light that reaches the photosensitive element 13a is very low.

Thus, the erroneous operation of the tape end detection can be prevented regardless of the material (color, transparency, reflectivity) of the tape cassette. Further, since the light shielding member can be easily attached to the wall portion 16c in the manufacture of the magnetic tape cartridge, the double-colored wall portion 16c can be formed in the manufacture of the magnetic tape cartridge, or the light shielding holder can be attached to the wall portion 16c, the productivity is not so low as in the conventional case. Further, since the light shielding member may be attached to only one wall portion 16c and the wall portion 16c that is not the outer surface of the cartridge case 1, or the two-color wall portion 16c may be formed in the process of manufacturing the cartridge, or the light shielding holder may be attached to the wall portion 16c, a desired color can be maintained as much as possible as the color of the cartridge case when the cartridge case main body is made of a material having high transparency.

Fig. 14 is a main part perspective view of the lower case section 2 of the ninth embodiment of the present invention. In fig. 14, in the ninth embodiment, the light shielding portion 15 is provided around the sensor optical path hole 17d of the next wall portion 16d, not after the light from the light emitting element 12 is passed through the tape housing chamber 4 on the left side (tape feeding side). The configuration of the light shielding portion 15 is the same as that of the eighth embodiment.

In this ninth embodiment, it is desirable to have the same action and effect as those of the above-described eighth embodiment.

Further, as a modification of the eighth and ninth embodiments, the light shielding portion 15 may be provided around both the sensor optical path hole 17c and the next sensor optical path hole 17d after the light from the light emitting element 12 passes through the tape housing chamber 4. According to this modification, since the light blocking effect of unnecessary light can be further improved, it is possible to more reliably prevent malfunction of the tape end detection. However, since the light shielding portion 15 is provided at two positions, there is a disadvantage in terms of production efficiency, but the effect is more remarkable than that of the conventional example.

Fig. 15 and 16 show a tenth embodiment of the present invention, fig. 15 is a perspective view of a main part of the lower case portion 2, and fig. 16 is a perspective view of a tape spacer. In fig. 15 and 16, in example 10, the tape spacer 18 itself disposed between the sensor optical path hole 17c of the wall portion 16c and the sensor optical path hole 17d of the next wall portion 16d after the light from the light emitting element 12 passes through the tape housing chamber 4 is configured as the light shielding portion 15. That is, in the prior art, the tape spacer 18 is formed of a transparent member, but in the present embodiment, it is formed of a material and a color having a light shielding effect as the light shielding portion 15. In fig. 15, reference numeral 30 denotes a tape guide shaft, and the tape spacer 18 is disposed between the tape guide shaft 30 and the wall portion 16c to prevent the tape from slackening.

In this tenth embodiment, the same action and effect as those of the above-described eighth and ninth embodiments can be obtained. In addition, in the tenth embodiment, since it is needless to say that the necessary assembling process of the tape shim 18 can be performed, the production efficiency is improved as compared with the conventional example.

Fig. 17 is a main portion perspective view of the lower case 2 according to the eleventh embodiment of the present invention. In fig. 17, in the eleventh embodiment, a cylindrical light shielding member 31 as a light shielding portion 15 is provided between the sensor optical path hole 17c of the wall portion 16c and the sensor optical path hole 17d of the next wall portion 16c after the light from the light emitting element 12 passes through the tape housing chamber 4 on the left side (the tape feeding side), and at a position not to hinder the tape running of the Y tape. The cylindrical light blocking member 31 is made of a material and a color having a light blocking effect, and has a sensor optical path hole 31a having a length N therein.

The sensor optical path hole 31a of the cylindrical light shielding member 31 may have a length that does not interfere with the tape running, and the center of the sensor optical path hole 31a is disposed on a straight line L2 connecting the position of the light emitting element 12 and the position of the light receiving element 13 b. The diameter of the sensor optical path hole 31a is set to be at least the same as the diameters of the respective sensor optical path holes 17a to 17 d.

In the tenth example, it is desirable to have the same operation and effect as those of the seventh example. That is, the unnecessary light is generally not directly incident on the light receiving element 13b, but enters the sensor optical path hole 31a of the cylindrical light blocking member 31, reaches the inner surface having the length N, and is blocked by the absorption effect. In this way, in the eleventh embodiment, by simply adding the cylindrical light shielding member 31, it is possible to prevent the malfunction of the tape end detection regardless of the material (color, transparency, reflectance) of the tape cartridge case 1, to adapt to mass production without lowering the production efficiency, and to maintain the originally intended color as much as possible as the color of the tape cartridge case 1 when the tape cartridge case body is made of a material having high transparency.

Fig. 18 is a main part perspective view of the lower shell section 2 of the twelfth embodiment of the present invention. In fig. 18, in the twelfth embodiment, similarly to the eleventh embodiment, a light shielding wall 32 as a light shielding portion 15 is newly provided between the sensor optical path hole 17c of the wall 16c after the light from the light emitting element 12 passes through the tape housing chamber 4 on the left side (the tape feeding side) and the sensor optical path hole 17d of the next wall 16c at a position not interfering with the tape running. The light shielding wall portion 32 is made of a material and a color having a light shielding effect. A sensor light path hole 32a is formed in the light shielding wall 32, and the center of the sensor light path hole 32a is disposed on a straight line L2 connecting the position of the light emitting element 12 and the position of the light receiving element 13 b. The size of the sensor optical path hole 32a is set to be at least as large as the sensor optical path holes 17a to 17 d. The light shielding wall 32 may be separately attached after the manufacture of the cartridge case or may be formed by two-color molding in the process of manufacturing the cartridge case.

In the twelfth embodiment, it is desirable to have the same light shielding effect as the eighth and ninth embodiments.

Further, the eleventh or twelfth embodiment may function alone as described above, but may be combined with the eighth or ninth embodiment, and the effect of preventing malfunction may be further improved by the combination.

Fig. 19 is a table showing a list of malfunction evaluation results in the eighth to eleventh embodiments and the respective comparative examples. In comparative example 4, a light shielding portion was provided around the sensor optical path hole 17a of the wall 16a on the side where the light from the light emitting element 12 entered the tape housing chamber 4. In comparative example 5, a light shielding portion was provided around the sensor optical path hole 17b of the wall 16b on the side where light from the light emitting element 12 entered the tape housing chamber 4. Comparative example 6 is a case where no light-shielding measure was taken.

The markers for the evaluation results were: the symbol "o" indicates that there is no problem in the operation of the commercial VTR, and the symbol "x" indicates that malfunction often occurs in the commercial VTR. As is clear from fig. 19, in the embodiment of the present invention, the malfunction of the tape end detection can be prevented regardless of the material (color, transparency, reflectivity) of the cassette case 1.

FIG. 20 is a schematic longitudinal sectional view of a magnetic tape cartridge of a thirteenth embodiment of the present invention. In fig. 20, in the thirteenth embodiment, both the upper flange 5a and the lower flange 5b of the pair of reels 5, 5 are made of a material that attenuates reflected light and a color (for example, black). In fig. 20, the upper flange 5a and the lower flange 5b made of a material that attenuates reflected light, or the like, are indicated by hatching.

According to the thirteenth embodiment, in the light emitting element 12, the unnecessary light 23 which is not directed toward the photosensitive element 13a and the unnecessary light 23 which is incident into the tape cartridge case 1 from the upper surface window of the tape housing chamber 4 of the tape cartridge or the like reach the upper and lower flanges 5a, 5b of the reel 5, and the reflected light thereof is attenuated, that is, shielded from light by its absorption effect. In this way, in the thirteenth embodiment, by simply attaching the reel 5 subjected to the light shielding treatment, it is possible to prevent a malfunction of tape end detection regardless of the material (color, transparency, reflectance) of the tape cassette case 1, to adapt to mass production without lowering the production efficiency, and to maintain the originally intended color as much as possible as the color of the tape cassette case 1 when the tape cassette case 1 main body is made of a material having high transparency.

In the thirteenth embodiment, the light-shielding process is performed on the pair of reels 5, but the light-shielding process may be performed only on either the right side (tape winding side) or the left side (tape feeding side). Further, both the upper flange 5a and the lower flange 5b of each reel 5 may be subjected to light shielding treatment, or only the upper flange 5a or the lower flange 5b may be subjected to light shielding treatment.

The thirteenth embodiment may function alone as described above, but may be combined with the first to seventh embodiments and the eighth to twelfth embodiments, and the effect of preventing malfunction can be further improved by the combination.

In the configuration for tape end detection on the tape winding side in the first to seventh embodiments, the light shielding devices disclosed in the eleventh and twelfth embodiments are not shown, but the light shielding devices disclosed in the eleventh and twelfth embodiments may be used on the tape winding side.

(magnetic tape cartridges of the embodiment relating to the presence or absence of magnetic tape cartridges)

Fig. 21 to 24 show a fourteenth embodiment of the present invention, and fig. 21(a) is a plan view of an upper face portion of a cartridge case from which only a magnetic tape cartridge is removed; FIG. 21(B) is a rear view of the magnetic tape cartridge; fig. 21(C) is a side view of the magnetic tape cassette, fig. 22 is a partially enlarged view of the MM portion of fig. 21(a), fig. 23 is a view showing an optical path of the detection light incident on the prism portion of the side surface portion, and fig. 24 is a view showing an optical path of the detection light incident on the prism portion of the rear surface portion.

In fig. 21, first, a cartridge non-detection device 112 on the device (recording/reproducing device, cartridge changer, etc.) side where the magnetic tape cartridge TTC of the fourteenth embodiment can be used will be described. The cartridge magnetic tape non-detection device 112 has a light-emitting portion 112a provided on the device side and a light-receiving portion 112b that receives detection light from the light-emitting portion 112a, and is set such that: the light path CC1 (in the figure, the center of CC1 is shown) of the detection light reaching the light receiving portion 112b from the light emitting portion 112a passes from the side to the front of the magnetic tape cartridge TTC, and thereby passes through the magnetic tape cartridge position. From the light emitting portion 112a, emission is actually performed with a width of about 30 degrees (15 degrees on one side) at the light emission angle.

On the other hand, the cartridge case 120 of the magnetic tape cartridge TTC is formed of a material (e.g., polystyrene) having high transparency and having a substantially flat rectangular parallelepiped shape, the upper surface portion 120a, the bottom surface portion 120b, the pair of left and right side surface portions 120c, the front surface portion 120d, and the rear surface portion 120 e. A partitioning inner wall 122 forming a pair of tape storage chambers 121, 121 is provided inside the tape cassette housing 120, and a pair of wound magnetic tapes (not shown) are rotatably stored in the pair of tape storage chambers 121, 121.

In addition, at a position on the optical path CC1 of the detection light corresponding to the cartridge case 120, the prism portions 123 and 124 are provided at a position where the detection light emitted from the light emitting portion 112a is first incident, specifically, at a portion of the side surface portion 120c and the back surface portion 120e adjacent to the side surface portion 120c, respectively (in fig. 21 a, the regions where the prism portions 123 and 124 are provided are hatched for clarity of the position).

As shown in fig. 22, the prism portions 123 and 124 of the side surface portion 120c and the rear surface portion 120e are formed continuously in parallel, and are formed simultaneously by integral molding when the tape cassette housing 120 is molded. The prism 123 of the side surface 120c has an apex angle of 30 degrees, and the prism 124 of the back surface 120e has an apex angle of 60 degrees.

In the above configuration, when the magnetic tape cassette TTC is positioned in the magnetic tape cassette position of the apparatus, the detection light from the light emitting unit 112a is irradiated around the light path CC 1. As shown in fig. 23, the detection light enters the side surface portion 120c of the magnetic tape cassette TTC at an incident angle of about 70 degrees (an angle with respect to the normal incidence line LL 1) at the center of the incident angle, and exits at an exit angle of 23 degrees with respect to the normal incidence line LL1 by refraction by the prism portion 123. Thus, the light is emitted in a direction greatly deviated from the optical path CC1 of the incident light. The deflection angle (difference between incident light and output angle) of the prism portion 123 is 47 degrees.

Alternatively, as shown in fig. 24, the detection light enters the side surface portion 120e of the magnetic tape cassette TTC at about 40 degrees (an angle with respect to the normal incidence line LL 2) at the center of the incident angle, and is projected at a projection angle of 54.5 degrees with respect to the exit surface 124a of the prism portion 124, and therefore, the critical angle of the prism portion 124 is about 40 degrees, and is totally reflected. Thus, the light is emitted in a direction greatly deviated from the optical path CC1 of the incident light. As described above, the detection light irradiated on the tape cassette TTC hardly reaches the light receiving portion 112b by refraction or reflection of the prism portions 123 and 124, and a tape cassette detection error in the tape cassette TTC of the tape cassette case 120 having high transparency can be prevented.

In addition, according to the fourteenth embodiment, the apex angle of the prism portion 123 of the side surface portion 120c is 30 degrees and the apex angle of the prism portion 124 of the rear surface portion 120e is 60 degrees, but the prism portions 123 and 124 may be formed so as to refract or reflect incident light in the emission direction in which the incident light does not reach the light receiving portion 112 b.

Fig. 25 shows a fifteenth embodiment of the present invention, and is a diagram showing a prism portion disposed in a portion shown in a partially enlarged view of the MM portion in fig. 21 (a). In the fifteenth embodiment, an inner wall 130 parallel to the side surface portion 120c is formed inside the tape cassette housing 120 in addition to the prism portion 123 of the side surface portion 120c and the prism portion 124 of the back surface portion 120e in the fourteenth embodiment, and a prism portion 123 having the same apex angle of 30 degrees as the prism portion 123 of the side surface portion 120c is formed on one surface thereof, and the other portions are the same as those in the fourteenth embodiment. The inner wall 130 is formed to extend to the partition inner wall 122. Thus, at the corner (R portion) 120f where the side surface portion 120c and the back surface portion 120e intersect, the prism portion 123 of the inner wall 130 refracts the incident light entering from the light emitting portion 112a by leakage in the light in the exit direction not reaching the light receiving portion 112b, and thereby it is possible to prevent a cartridge detection error in the cartridge TTC of the cartridge case 120 having high transparency.

Fig. 26 to 28 show a sixteenth embodiment of the present invention, and fig. 26(a) is a plan view of an upper face portion of a cartridge case from which only a magnetic tape cartridge is removed; FIG. 26(B) is a rear view of the magnetic tape cartridge; fig. 26(C) is a side view of the magnetic tape cassette, fig. 27 is a partially enlarged view of the NN portion of fig. 26(C), and fig. 28 is a view showing an optical path of detection light incident on the prism portion of the bottom surface portion.

In fig. 26, first, the cartridge non-detection device 113 on the device side to which the magnetic tape cartridge TTC of the sixteenth embodiment can be used is explained. The cartridge magnetic tape non-detection device 113 includes a light-emitting portion 113a provided on the device side and a light-receiving portion 113b for receiving detection light from the light-emitting portion 113a, and is configured such that: the light path CC2 (in the figure, the center of CC2 is shown) of the detection light reaching the light receiving portion 113b from the light emitting portion 113a passes from the bottom surface to the top surface of the magnetic tape cartridge TTC, thereby passing through the magnetic tape cartridge position. Light is actually emitted from the light emitting portion 113a with a width of about 30 degrees (one side 15 degrees) at the light emitting angle.

On the other hand, the cartridge case 120 of the magnetic tape cartridge TTC has a substantially flat rectangular parallelepiped shape formed by an upper surface portion 120a, a bottom surface portion 120b, a pair of left and right side surface portions 120c, a front surface portion 120d, and a rear surface portion 120e, and is formed of a material having high transparency (for example, polystyrene). A partitioning inner wall 122 forming a pair of tape storage chambers 121, 121 is provided inside the tape cassette housing 120, and a pair of wound magnetic tapes (not shown) are rotatably stored in the pair of tape storage chambers 121, 121.

Further, a prism portion 125 is provided at a position on the optical path CC2 of the detection light corresponding to the cartridge case 120, where the detection light emitted from the light emitting portion 113a is first incident, specifically, at a portion of the bottom surface portion 120b (in fig. 26 a, the region where the prism portion 125 is provided is hatched for clarity of the position).

As shown in fig. 27, the prism portions 125 of the bottom surface portion 120b are formed continuously in parallel, and are formed simultaneously by integral molding when the cartridge case 120 is molded. The prism portion 125 of the bottom surface portion 120b has an apex angle of 30 degrees.

In the above configuration, when the magnetic tape cassette TTC is positioned in the magnetic tape cassette position of the apparatus, the detection light from the light emitting unit 113a is irradiated around the light path CC 2. As shown in fig. 28, the detection light enters the bottom surface portion 120b of the magnetic tape cassette TTC at an incident angle of about 20 degrees (an angle with respect to the normal incidence line LL 3) at the center of the incident angle, and is projected at a projection angle of 49 degrees with respect to the emission surface 125a of the prism portion 125, and is totally reflected because the critical angle of the prism portion 125 is about 40 degrees. Thus, the light is emitted in a direction greatly deviated from the optical path CC2 of the incident light. Thus, the detection light irradiated on the magnetic tape cassette TTC is reflected by the prism portion 125 and hardly reaches the light receiving portion 113b, and a magnetic tape cassette detection error in the magnetic tape cassette TTC of the magnetic tape cassette case 120 having high transparency can be prevented.

Further, according to the second embodiment, the apex angle of the prism portion 125 of the bottom surface portion 120b is formed to be 30 degrees, but the prism portion 125 may be formed so that the incident light is refracted or reflected in the emission direction that cannot reach the light receiving portion 113 b.

Fig. 29 shows a seventeenth embodiment of the present invention, and fig. 29(a) is a plan view of an upper face portion of a cartridge case from which only a magnetic tape cartridge is removed; FIG. 29(B) is a rear view of the magnetic tape cartridge; fig. 29(C) is a side view of the magnetic tape cartridge.

In fig. 29, this magnetic tape cartridge TTC is a structure that can be used in the apparatus of the fourteenth or sixteenth embodiment described above. That is, the prism portions 123, 124, 125 are provided at positions on the two light paths CC1, CC2 of the detection light of the tape cartridge case 120 (the side surface portion 120c of the tape cartridge case 120 and a part of the back surface portion 120e close to the side surface portion 120c as in the fourteenth and fifteenth embodiments; and the bottom surface portion 120b as in the sixteenth embodiment), respectively (in fig. 29(a), regions where the prism portions 123, 124, 125 are provided are hatched for clarity of the positions). The prism portions 123, 124, and 125 have the same configuration as that of the fourteenth (or fifteenth) and sixteenth embodiments, and therefore, the description thereof will be omitted to avoid redundancy.

In the magnetic tape cartridge TTC of the seventeenth embodiment, when used in the apparatus of the fourteenth or sixteenth embodiment, the detection light irradiated on the magnetic tape cartridge TTC hardly reaches the light receiving portions 112b and 113b by refraction or reflection of the prism portions 123, 124, and 125, and a magnetic tape cartridge detection error in the magnetic tape cartridge TTC of the magnetic tape cartridge case 120 having high transparency can be prevented.

In the fourteenth to seventeenth embodiments, since the prism portions 123, 124, 125 are formed by integral molding with the tape cassette housing 120, and since the prism portions 123, 124, 125 are molded simultaneously with the tape cassette housing 120, the prism portions 123, 124, 125 can be easily manufactured at low cost. However, the prism portions 123, 124, 125 may be separately manufactured from the cartridge case 120 and then attached to the cartridge case 120.

In the fourteenth, fifteenth, and seventeenth embodiments described above, since the prism section 123 is provided at the position of the cassette case 120 where the detection light emitted from the light emitting section 112a first enters, the distance from the prism section 123 to the light receiving section 112b is large, and even if the deflection angle of the prism is set small, the detection light is prevented from reaching the light receiving section 112b, and therefore, the degree of freedom in designing the prism section 123 is increased. Further, a prism portion may be provided at a position of the cartridge case 120, specifically, the front portion 120d, where the detection light emitted from the light emitting portion 112a is not first incident but is second incident.

In the fourteenth to seventeenth embodiments, since the prism portions 123, 124, 125 are provided on the inner surface side of the cartridge case 120, the surfaces of the prism portions 123, 124, 125 are hardly damaged by abrasion, scratch, or the like.

Therefore, in order to obtain the same effect as the present invention, the light shielding member may be provided at the position of the prism portion 123, 124, 125, but when the prism portion 123, 124, 125 is formed integrally with the tape cassette housing 120, there is an advantage that the mounting process is not required, and problems such as mounting error, falling-off, etc. do not occur, as compared with the case where the light shielding member is provided, and further, the size is dominant.

Further, according to the above-described fourteenth to seventeenth embodiments, examples of the magnetic tape cassette TTC that can be adapted to such a case are shown: the case where the light path CC1 for the detection light passes through the position of the magnetic tape cartridge by passing from the side surface to the front surface of the magnetic tape cartridge TTC and the case where the light path CC2 for the detection light passes through the position of the magnetic tape cartridge by passing from the bottom surface to the top surface of the magnetic tape cartridge TTC, however, it is obvious that the present invention can be applied to the case where other light paths are passed as well.

Further, according to the above-described fourteenth to seventeenth embodiments, the prism sections 123, 124, 125 are provided only at positions on the two optical paths CC1, CC2 equivalent to the cartridge case 120, but if the same prism sections 123, 124, 125 are provided symmetrically left and right, the size becomes dominant, and further, a greater degree of freedom in designing the cartridge with the non-detecting devices 112, 113 can be obtained.

Fig. 30 to 32 show an eighteenth embodiment of the present invention, fig. 30 being a partial plan view of the upper face side of the cartridge case 120 with the magnetic tape cartridge TTC removed; fig. 31 is a perspective view showing a main part of the light shielding member 117 before mounting; fig. 32 is a perspective view showing a main part in a state where the light shielding member 117 is mounted.

In fig. 30, since the device-side magnetic tape cassette non-detecting device 112 capable of using the magnetic tape cassette TTC of the eighteenth embodiment is the same as that of the fourteenth embodiment (or the fifteenth embodiment), the same reference numerals are used in the drawings and the description thereof is omitted. The tape end detection device 114 is provided on the device side, and the tape end detection device 114 includes a light emitting portion 114a and a pair of light receiving portions 114b (the other half is not shown) for detecting the end of the tape, which receive the detection light from the light emitting portion 114 a. In the state where the magnetic tape cassette TTC is mounted in the apparatus, the light emitting section 114a is disposed on the central cylindrical wall section 115a, and the pair of light receiving sections 114b are located at outer positions on the left and right side surfaces of the magnetic tape cassette TTC.

On the other hand, the cartridge case 120 of the magnetic tape cartridge TTC has the same configuration as that of the above-described fourteenth embodiment and is formed of a material having high transparency, and the light paths 116a to 116e are provided in the wall portion 115a, the partition inner wall 122, the wall portion 115b, and the side surface portion 120c on the optical path CC3 for tape end detection connecting the light emitting portion 114a and the light receiving portion 114b of the tape end detection device 114, respectively. A light blocking member 117 is attached to the wall portion 115b at the position of the light passage 116 d. At the position of the light path CC3 of the light blocking member 117, a light exit passage 117a is opened, and the detection light passing through the light path CC3 is passed, and the unnecessary light other than the light path CC3 is blocked from passing. That is, even if the cartridge case 120 is formed of a material having high transparency, erroneous detection of the tape end detection can be reliably prevented.

One end side of the light blocking member 117 extends to a position blocking the light passage 116d of the wall portion 115 b. The extension 117b is bent at a position having the light path 117a, and is disposed on the optical path CC1 for non-detection of the cassette tape.

In this eighteenth embodiment, only the light passing through the light path CC3 among the detection lights detected by the tape ends can pass through the light passage 117a of the light shielding member 117, and the light other than the light path CC3 is blocked from passing by the light shielding member 117, and therefore, in the case of being formed with a cassette casing having high transparency, erroneous detection of the tape end detection can be reliably prevented. Further, since the light for non-detection of the magnetic tape cartridge is blocked by the extending portion 117b of the light blocking member 117, when the magnetic tape cartridge is formed by a magnetic tape cartridge case having high transparency, an error of non-detection of the magnetic tape cartridge can be reliably prevented. Further, in the process of preventing the cartridge tape non-detection error, since the light shielding member 117 for preventing the tape end mis-detection is used, the cartridge tape non-detection error can be prevented without increasing the number of parts and without causing deterioration of the assembling property.

Fig. 33 is a plan view showing a nineteenth embodiment of the present invention, in which only the upper surface of the cassette case is removed, and fig. 34(a) is a schematic view showing the periphery of a notch portion for an optical path of the cassette case; FIG. 34(B) is a view showing the optical path of the tape end detection light when a prism portion is provided; fig. 34(C) is a diagram showing the optical path of the tape end detection light when the prism portion is not present.

In the nineteenth embodiment, in a method in which leader tapes having high transparency are provided at both ends of a magnetic tape and tape ends are detected by the tape end detection light (tape end detection light) CC3 of the light emitting part 114a of the tape end detection device 114, the tape end detection light CC3 passes through the gap for the optical path of the highly transparent tape cassette housing 120 and reaches a tape end detection error (tape end detection error) in the tape cassette TTC of the left and right light emitting parts 114b, 114 b. That is, the left and right inner walls 122, 122 surrounding the notches 122b, 122c for the optical path on both sides of the right cylindrical wall 122a constituting the insertion hole of the light emitting section 114a for detecting the tape end are formed with notches 122d, 122e for the optical path, respectively, and the inner walls 122 surrounding the notches 122d, 122e are provided with light emitting directions in which the tape end detection light CC3 from the light emitting section 114a is refracted or reflected to the prism sections 126, 127 so as not to reach the left and right light receiving sections 114b, respectively.

Prism portions 128 and 129 are provided on the walls around the notches 122f and 122g for the optical paths on the front sides of the left and right side surfaces 120c and 120c of the cartridge case 120, respectively, for refracting or reflecting the tape end detection light CC3 from the light emitting portion 114a in the emission direction that does not reach the left and right light receiving portions 114b and 114 b. Other configurations are the same as those of the fourteenth embodiment, and therefore the same reference numerals are given to the same components, and detailed description thereof is omitted.

In the tape cassette TTC of the nineteenth embodiment, the tape termination detection light CC3 hardly reaches the left and right light receiving portions 114b, 114b by refraction or reflection of the prism portions 126 to 129, and thus a tape end detection error of the tape cassette TTC of the highly transparent tape cassette case 120 can be prevented.

When the prism portion 126 is provided around the notch 122d through which the tape end detection light CC3 passes as shown in fig. 34(a) and (B), the light from the light emitting portion 114a is not directly emitted, but is refracted or reflected in a direction not reaching the light receiving portion 114B as shown in fig. 34 (B). Theoretically, although the prism portion may be formed on one surface, when the incident light angle to the prism portion is small, and the prism portion is formed integrally with the tape cassette housing 120, the curved portion (R portion) and the surface property provided at the apex and corner portions of the prism portion cause a direct component of the remaining light to reach the light receiving portion and malfunction, and therefore, as shown in fig. 33, the prism portions 126 to 129 are formed at a plurality of positions on the partition inner wall 122, thereby increasing the reliability.

In the case of performing the tape end detection and the cartridge tape non-detection, it is needless to say that any selection from the first embodiment to the nineteenth embodiment described above or a combination of the plurality of embodiments may be performed.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, according to the invention of claim 1, since the light shielding portion having the light shielding effect is provided around at least one of the sensor optical path hole and the next sensor optical path hole after the light from the light emitting element passes through the tape housing chamber, the light shielding portion can be provided around the sensor optical path hole at up to two positions, and therefore, the erroneous operation of the tape end detection can be prevented regardless of the material (color, transparency, reflectance) of the tape cartridge case, and mass production can be realized without excessively lowering the production efficiency, and even in the case where the tape cartridge case main body is made of a material having high transparency, the originally intended color can be maintained as much as possible as the color of the tape cartridge case.

According to claim 2 of the present invention, in the magnetic tape cartridge of claim 1, the light shielding portion is provided: the tape cassette has a width of about 1mm or more extending from the center of the optical path connecting the position of the light emitting element and the position of the light receiving element with a straight line to the left and right, and spans the entire height of at least one of the wall portion and the next wall portion after the light from the light emitting element passes through the tape housing chamber, and therefore, the erroneous operation of the tape end detection can be reliably prevented in addition to the effect of the invention of claim 1.

According to claim 3 of the present invention, in the magnetic tape cartridge according to claim 1 or 2, the light shielding portion is constituted by the light shielding member attached to at least one of the wall portion and the next wall portion after the light from the light emitting element passes through the tape housing chamber, and therefore, in addition to the effects of the invention according to claim 1 or 2, since the light shielding member can be attached to the wall portions at up to two positions, the productivity can be further improved.

According to claim 4 of the present invention, in the magnetic tape cartridge according to claim 1 or 2, the light shielding portion is formed by forming at least one of the wall portion and the next wall portion itself after the light from the light emitting element passes through the tape housing chamber with a two-color light shielding material in molding the magnetic tape cartridge, and therefore, in addition to the effect of the invention according to claim 1 or 2, a two-color magnetic tape cartridge case can be formed, and the productivity can be further improved.

According to the invention of claim 5, in the magnetic tape cartridge according to claim 1 or 2, the light shielding portion is formed by attaching the light shielding bracket having the hole for the sensor optical path to at least one of the wall portion and the next wall portion after the light from the light emitting element passes through the magnetic tape housing chamber, and therefore, in addition to the effect of the invention of claim 1 or 2, the light shielding bracket can be attached to at least two wall portions, and the productivity can be further improved.

According to the invention of claim 6, there is provided a magnetic tape cartridge comprising a pair of reels rotatably disposed in a pair of cartridge accommodating chambers, and a magnetic tape wound around the pair of reels and accommodated therein, the magnetic tape comprising a magnetic recording layer magnetic tape portion and a highly light-transmissive tape portion attached to both end sides thereof, wherein sensor optical path holes are provided in respective wall portions on a straight line connecting a position of the light emitting element and a position of the photosensitive element so that light from the light emitting element of a recording/reproducing apparatus is incident on the tape accommodating chambers in a state of being mounted in the recording/reproducing apparatus, and light passing through a tape path of the tape accommodating chambers passes through the tape accommodating chambers and passes through the cover accommodating chambers to reach the photosensitive elements of the recording/reproducing apparatus, wherein a cylindrical protrusion having a light shielding effect is provided on a cover lock member disposed in the cover lock accommodating chambers, since the cylindrical projection is provided with the sensor optical path hole which is arranged on a straight line connecting the position of the light emitting element and the position of the light receiving element in a state where the cover lock member is located at the unlock position, even if unnecessary light enters the sensor optical path hole of the cylindrical projection and reaches the inner surface of the sensor optical path hole, the light is shielded by its absorption effect, so that the malfunction of the tape end detection can be prevented regardless of the material (color, transparency, and reflectance) of the tape cartridge case, mass production can be realized without excessively lowering the production efficiency, and even in a case where the tape cartridge case main body is made of a material having high transparency, the original desired color can be maintained as much as possible as the color of the tape cartridge case.

According to the invention of claim 7, there is provided a magnetic tape cartridge comprising a pair of reels rotatably disposed in a pair of cartridge accommodating chambers, and a magnetic tape wound around the pair of reels and accommodated therein, the magnetic tape comprising a magnetic recording layer magnetic tape portion and a highly light-transmissive tape portion attached to both end sides thereof, wherein sensor optical path holes are provided in respective wall portions on a straight line connecting a position of the light emitting element and a position of the photosensitive element so that light from the light emitting element of a recording/reproducing apparatus is emitted into the cartridge accommodating chambers in a state of being mounted in the recording/reproducing apparatus, and light passing through a tape path of the cartridge accommodating chambers passes through the cartridge accommodating chambers and reaches the photosensitive element of the recording/reproducing apparatus, characterized in that at least one of upper and lower flanges on the pair of reels is formed of a material and a color which attenuates reflected light, therefore, since unnecessary light reaches the flange surface of the reel and is shielded by the absorption effect, erroneous detection of the tape end can be prevented regardless of the material (color, transparency, reflectance) of the tape cartridge case, mass production can be realized without lowering the production efficiency excessively, and even when the tape cartridge case main body is made of a material having high transparency, the originally desired color can be maintained as much as possible as the color of the tape cartridge case.

According to the invention of claim 8, there is provided a magnetic tape cartridge for use in an apparatus for detecting the presence or absence of a magnetic tape cartridge, the apparatus being provided with a light emitting portion and a light receiving portion for receiving a detection light from the light emitting portion, an optical path of the detection light reaching the light receiving portion from the light emitting portion being set to pass through a position of the magnetic tape cartridge, and the presence or absence of the magnetic tape cartridge being detected based on whether or not the detection light from the light emitting portion reaches the light receiving portion, characterized in that a cartridge case is formed of a material having high transparency, a prism portion for refracting or reflecting incident light to a direction of light emission which does not reach the light receiving portion is provided at a position corresponding to the cartridge case on an optical path of the detection light, and therefore, when the magnetic tape cartridge is positioned at the cartridge position, the detection light from the light emitting portion is refracted or totally reflected by the prism portion so as not to reach, therefore, tape detection errors in the tape cassette of the tape cassette case having high transparency can be prevented.

According to claim 9 of the present invention, in the magnetic tape cartridge according to claim 8, since the prism portion is formed by being integrally molded with the cartridge case, in addition to the effect of the invention of claim 1, since the prism portion is molded simultaneously with the cartridge case, the prism portion is easily manufactured at low cost. Further, compared with the case where the light shielding member is provided at the position of the prism portion, the mounting process is not required, and therefore, there is a problem that mounting failure, detachment, or the like does not occur.

According to claim 10 of the present invention, in the magnetic tape cartridge according to any one of claims 8 and 9, since the prism portion is provided at a position of the magnetic tape cartridge case where the detection light emitted from the light emitting portion first enters, in addition to the effects of the inventions of claims 8 and 9, a distance from the prism portion to the light receiving portion becomes large, and even if the deflection angle of the prism is set small, the detection light is prevented from reaching the light receiving portion, and thus, the degree of freedom in designing the prism increases.

According to the invention of claim 11, there is provided a magnetic tape cartridge for use in a device for detecting the presence or absence of a magnetic tape cartridge, the device being provided on a side thereof with a light emitting portion for detecting the presence or absence of a magnetic tape cartridge and a light receiving portion for detecting the presence or absence of a magnetic tape cartridge, wherein an optical path of a detection light reaching the light receiving portion from the light emitting portion is set to pass through a position of the magnetic tape cartridge, and the presence or absence of a magnetic tape cartridge is detected based on whether or not the detection light from the light emitting portion reaches the light receiving portion, and wherein the device for detecting the end of a magnetic tape is provided on a side thereof with a light emitting portion for detecting the end of a magnetic tape and a light receiving portion for detecting the end of a magnetic tape for sensing the detection light from the light emitting portion, and wherein a fus light shielding member is provided on an optical path for detecting the end of a magnetic tape, the light shielding member is extended so that the extended portion is disposed on the optical path for detecting the presence of a tape cartridge, thereby preventing erroneous detection of the tape end in a cassette case having high transparency without increasing the number of parts, deteriorating the assembling property, and preventing erroneous detection of the tape cartridge.

According to the invention of claim 12, there is provided a magnetic tape cassette for use in an apparatus for detecting a tape end based on whether or not a tape end detection light from a light emitting unit reaches a light receiving unit, wherein a prism unit for refracting or reflecting the tape end detection light from the light emitting unit in an emission direction not to reach the light receiving unit is provided on a wall around a notch for an optical path through which the tape end detection light passes, and therefore, the tape end detection light from the light emitting unit is refracted or totally reflected by the prism unit not to reach the light receiving unit, and a tape cassette detection error in a magnetic tape cassette of a cassette case having high transparency can be prevented.

According to the invention of claim 13, there is provided a magnetic tape cartridge for use in a device for detecting presence or absence of a magnetic tape cartridge, wherein two sets of a light emitting portion for detecting presence or absence of a magnetic tape cartridge and a light receiving portion for detecting presence or absence of a magnetic tape cartridge are provided on a side of the device, first and second light paths of first and second detection lights reaching the light receiving portions from the light emitting portions are set to pass through a position of the magnetic tape cartridge, presence or absence of a magnetic tape cartridge is detected based on whether or not the first or second detection light from the light emitting portions reaches the light receiving portions, and the magnetic tape cartridge is also used for detecting presence or absence of an end of a magnetic tape, wherein two sets of light emitting portions for detecting an end of a magnetic tape and light receiving portions for detecting an end of a magnetic tape are provided on the side of the device, third and fourth light paths of third and fourth detection lights reaching the light receiving portions from the light emitting portions are set to pass through a position of the magnetic tape, the tape cassette is characterized in that a cassette case is formed of a material having high transparency, prism portions for refracting or reflecting the first and second detection lights in a direction in which the first and second detection lights do not reach the respective light sensing portions are provided at positions corresponding to the cassette case on first and second light paths for detecting the presence of the tape cassette, and light blocking members for blocking passage of unnecessary light deviated from the respective light paths are provided on third and fourth light paths for detecting the third and fourth detection lights at the end of the tape.

According to the invention 14, there is provided a magnetic tape cassette for use in a device for detecting presence or absence of a magnetic tape cassette, the device being provided with two sets of a light emitting portion for detecting presence or absence of a magnetic tape cassette and a light receiving portion for detecting presence or absence of a magnetic tape cassette for detecting detection light from the light emitting portion, first and second light paths of first and second detection light reaching the light receiving portions from the light emitting portions being set so as to pass through positions of the magnetic tape cassette, and presence or absence of the magnetic tape cassette being detected based on whether the first or second detection light from the light emitting portions reaches the light receiving portions; in a tape end detecting apparatus for detecting the end of a tape, a tape end detecting device is provided with two sets of light emitting units for detecting the end of the tape and light receiving units for detecting the end of the tape for receiving the detecting light from the light emitting units, and third and fourth light paths for the third and fourth detecting lights reaching the light receiving units from the light emitting units are set to pass through the tape position, and the end of the tape is detected based on whether the third and fourth detecting lights from the light emitting units reach the light receiving units, wherein a tape cassette casing is formed of a material having high transparency, a prism unit for refracting or reflecting the first detecting light in a direction not to reach the light receiving units is provided at a position corresponding to the tape cassette casing on a first light path for detecting the first detecting light without tape, and a first light shielding member is provided on a second light path for detecting the second detecting light without tape, the third light shielding member for blocking the unnecessary light deviated from the third light path is provided on the third light path for detecting the third detection light of the tape end, and the third light shielding member for blocking the unnecessary light deviated from the fourth light path is provided on the fourth light path for detecting the fourth detection light of the tape end.

According to claim 15 of the present invention, in the magnetic tape cartridge according to claim 14, since the first shutter member is extended and the extended portion is used as the second shutter member, the number of parts and the number of assembling steps can be reduced in addition to the effect of the invention of claim 14, thereby improving the productivity.

Claims

1. A magnetic tape cartridge comprising:

a pair of tape storage chambers;

a pair of reels on which magnetic tapes are wound, the magnetic tapes being accommodated in the pair of tape accommodating chambers, the magnetic tapes each including a magnetic tape portion of a magnetic recording layer and highly light-transmissive tape portions attached to both ends of the magnetic tapes;

a first wall portion that forms an insertion hole into which a first light emitting element of a recording-reproducing apparatus is inserted when the magnetic tape cartridge is loaded into the recording-reproducing apparatus, the first wall portion having a first hole that can guide light emitted from the first light emitting element out of the insertion hole;

a second wall portion forming a part of the tape housing chamber and having a second hole for guiding the light emitted from the first light emitting element into the tape housing chamber;

a third wall portion forming another part of the tape housing chamber and having a third hole for guiding the light guided from the first light emitting element into the tape housing chamber out of the tape housing chamber;

a fourth wall portion forming a part of a cover lock member accommodating chamber for accommodating a cover lock member for locking a cover of the magnetic tape cartridge, the fourth wall portion having a fourth hole for guiding light guided out of the magnetic tape accommodating chamber from the first light emitting element into the cover lock member accommodating chamber;

a fifth wall portion forming another part of the cover lock member accommodating chamber and having a fifth hole for guiding the light guided from the first light emitting element into the cover lock member accommodating chamber out of the magnetic tape cartridge and then onto the first photosensitive element of the recording and reproducing apparatus;

a first light shielding member provided in the vicinity of at least one of the third wall portion and the fourth wall portion, the first light shielding member being formed from each of the tape storage compartments, the first light shielding member having a hole through which light emitted from the first light emitting element can pass; and

a second light shielding member provided in the vicinity of at least one of the third wall portion and the fourth wall portion, the second light shielding member being formed from each of the tape storage compartments, the second light shielding member blocking light emitted from a second light emitting element of the recording/reproducing apparatus for detecting absence of the cartridge, so as to prevent the light from the second light emitting element from reaching a second photosensitive element of the recording/reproducing apparatus;

wherein the first light shielding member is located in a position parallel to the fourth wall portion, and the second light shielding member is located in a position perpendicular to the fourth wall portion.

2. The tape cartridge according to claim 1, wherein the first shutter member and the second shutter member are connected and formed in one piece.

3. The tape cartridge according to claim 2, wherein the first shutter member and the second shutter member which are coupled and formed integrally are L-shaped.

4. A magnetic tape cartridge comprising:

a pair of tape storage chambers having a tape supply side and a tape take-up side;

a pair of reels on which magnetic tapes are wound, the magnetic tapes being accommodated in the pair of tape accommodating chambers, the magnetic tapes each including a magnetic tape portion of a magnetic recording layer and highly transparent tape portions attached to both ends of the magnetic tapes;

a first wall portion that forms an insertion hole into which a light emitting element of a recording and reproducing apparatus is inserted when the magnetic tape cartridge is loaded into the recording and reproducing apparatus, the first wall portion having a first hole that guides light emitted from the light emitting element out of the insertion hole;

a second wall portion forming a part of the tape supply-side tape housing chamber and having a second hole for guiding the light emitted from the light emitting element into the tape supply-side tape housing chamber;

a third wall portion that forms another part of the tape supply-side tape housing chamber and has a third hole for guiding light guided from the light emitting element into the tape supply-side tape housing chamber out of the tape supply-side tape housing chamber;

a fourth wall portion having a fourth hole for guiding the light emitted from the light emitting element directly out of the magnetic tape cartridge and then onto the photosensitive element of the recording and reproducing apparatus; and

and a light shielding member provided in the vicinity of the fourth wall portion, the light shielding member being a flat thin plate-like member formed from the fourth wall portion, the member having a hole through which light emitted from the light emitting element can pass.

5. The magnetic tape cartridge according to claim 4, wherein said light shielding member is provided: the light path center connecting the position of the light emitting element and the position of the light sensing element with a straight line has a width of not less than 1mm on the left and right sides, respectively, and covers the entire height of the fourth wall portion.

6. The magnetic tape cartridge according to claim 4, wherein said light shielding member is adhered to said fourth wall portion.