An arrangement for preventing entrance of harmful particles for use in a cartridge

Abstract: In a recording tape cartridge having a cartridge case, magnetic recording tape (2) and a front lid and a rear lid (11) for protecting the magnetic tape (2), there are provided en­ trance preventing members (50) at a bottom the cartridge case facing to clearances between side edges of the rear lid (11) and case body for preventing entrance of floating harmful particles into the area near the recording tape so as to preventing corrosion of the recording tape by the floating harmful particles.

Description: The present invention relates to a tape cartridge, and more particularly to a tape cartridge having a metal recording medium such as a magnetic recording tape. Description of the Prior Art according to EP-A-0 094 087: Figs. 1 to 6 show an example of a conventional tape cartridge, wherein a case body 1 is formed by assembling a top case half 1a and a bottom case half 1b made of plastic resin material together so that a pair of tape reels 3 are rotatably installed in the left and right portions of the case body 1. There are defined a pair of tape drawing openings 4 at the side end portions or left and right end portions in the front face of the case body 1. A pocket 5 for the tape loading is defined at the central portion of the case body in such a manner that the pocket 5 is expanded towards the inside of the case body 1 between the left and right tape drawing openings 4. In this arrangement, the magnetic tape 2 is taken out of one of the tape reels 3 through the tape drawing opening facing to the tape reel 3 which releases the recording tape and the released tape is advanced toward the front side of the pocket 5, then introduced in the other tape drawing opening and taken up by the other tape reel 3 in a known manner. A front lid 6 is mounted on the front part of the case body 1 for covering and protecting the front surface or recording surface of the magnetic tape 2 extending between the tape drawing openings 4. The front lid 6 is made of plastic resin and comprises a front wall 6s extending in a lateral direction so as to close the entire length of the front part of the case body 1, side arms 6b projected backward of the case body from both side ends of the front wall 6a and pivotal shafts 7 projected from the inner surfaces of the side arms 6b. The front lid 6 is pivotally mounted on both side walls 8 of the case body 1 by rotatably engaging the pivotal shafts 7 in recesses defined in the side walls 8, so that the front lid 6 is movable between a closed position or down position at which the front lid 6 covers the front face of the magnetic tape 2 as shown in the real line in Fig. 3 and up position or open position at which the front side of the magnetic tape 2 is opened as shown in chain lines in Fig. 3. The front lid 6 is normally exerted toward the closed position by a resilient member (not shown) engaged with one of the pivotal shafts 7. There is provided a rear lid 11 on the rear side of the front lid 6 in the area where the pocket 5 for the tape loading is defined. When the tape cartridge is not used, the rear lid 11 covers the rear surface of the magnetic tape 2, more specifically the rear lid 11 covers the inner side as well as the lower part of the magnetic tape 2 and the upper opened part of the pocket 5. The rear lid 11 is made of plastic resin and is formed by molding with a generally T character shape in a cross sectional view as shown in Fig. 3. The rear lid 11 comprises a slanted wall 12 for covering the rear face of the the magnetic tape 2, a top wall 13 projected form the top edge of the slanted wall 2 for covering the upper opening of the pocket 5, a pair of pivotal shafts 14 projected from the central area of both side edges 11a and 11b of the slanted wall 12 and a pair of sliding shafts 15 provided at the portions lower than the pivotal shafts 14 of the side edges 11a and 11b. The pivotal shafts 14 are rotatably engaged with the shaft supporting members 16 projected backward from the rear surface of the front lid 6 with the sliding shafts 15 slidably engaged in S shaped guide slots 18a and 18b which are respectively defined on the inner surface of the rear lid guide walls 5a and 5b in the pocket 5. The guide slots 18a and 18b are formed by assembling the guide walls 5a and 5b of the top case half 1a and the bottom case half 1b as shown in Fig. 4. The front lid 6 and the rear lid 11 can be opened upward from the closed position shown in the real line in Fig. 3. That is, when the front lid 6 is moved upward to its open position from the closed position, the rear lid 11 is also rotated with the movement of the front lid 6 around the pivotal shafts 14 and moved upward along the guide slots 18a and 18b, being opened upward as shown in the chain lines A in Fig. 3. In the conventional tape cartridge as explained above, in order to facilitate the movement of the rear lid 11, there are defined clearances S between the lateral edges 11a and 11b of the rear lid 11 and rear lid guide walls 5a and 5b as shown in Figs. 5 and 6. Therefore, even when the rear lid 11 is in the closed position, a very small part of the magnetic tape 2 is visible directly from the outside of the case body 1 through the clearances S. Thus, harmful substance in the air enters in the case body 1 through the clearances S and undesirably adheres onto the magnetic tape 2 particularly the lower edge portion of the tape resulting in an undesired problem of corrosion of the magnetic tape 2 in case the magnetic tape is provided with a magnetic layer made of metallic material such as cobalt, cobalt-nickel, or cobalt phosphorus formed on a non magnetic substrate such as plastic resin film. It has been observed that in particular, such corrosion is apt to occur in the evaporated magnetic tape formed without binder. Such harmful substances are sulfur, chlorine and other various floating substances of various compounds or mist of sulfuric acid and nitric acid. Such harmful substance mentioned above is referred to as floating harmful particles hereinafter. It is an object of the present invention to provide a tape cartridge of the type comprising a magnetic tape with the magnetic layer made of metallic material, a front lid and rear lid for protecting the magnetic tape, said tape cartridge being capable of eliminating corrosion of the magnetic tape by the harmful floating particles by preventing entrance of the harmful floating particles in the air through clearance between the rear lid and the case body assuring smooth movement of the front lid and rear lid. This object is solved with the features of claim 1. According to one aspect of the present invention, there is provided a tape cartridge of the type mentioned above, in which one or more wall members for covering or closing one or more openings through which the floating harmful particles may enter into the cartridge case, so that the floating harmful particles are prevented from entering into the cartridge case, whereby corrosion of the magnetic recording tape or disc can be avoided. Fig. 1 is a perspective view showing an example of a conventional tape cartridge, Fig. 2a is a top plan view of the tape cartridge shown in Fig. 1 with a part thereof broken, Fig. 2b is a enlarged top plan view of a part circled in Fig. 2a, Fig. 3 is a cross sectional view showing the front lid and rear lid in the tape cartridge shown in Fig. 1, Fig. 4 is an exploded perspective view of an essential portion of the tape cartridge shown in Fig. 1, Fig. 5 is a bottom plan view of a part of the tape cartridge shown in Fig. 1, Fig. 6 is a cross sectional view taken along lines D-D in Fig. 5, Fig. 7a is a partial top plan view showing an embodiment of the tape cartridge according to the present invention, Fig. 7b is an enlarged view of a part circled in Fig. 7a, Fig. 8 is a partial perspective view of the embodiment shown in Fig. 7a, Fig. 9 is a cross sectional view taken along the line B-B in Fig. 7a, Fig. 10 is a partial top plan view showing a second embodiment of the tape cartridge according to the present invention, Fig. 11 is a perspective view showing a essential part of the second embodiment shown in Fig. 10, and Fig. 12 is a cross sectional view taken along the lines C-C in Fig. 10. Before the description proceeds, it is noted that since the basic structure of the tape cartridge is similar to those of the conventional tape cartridge explained with reference to Figs. 1 to 6, like parts are designated by the same reference numerals and the explanation of details thereof is herein omitted for the brevity. Embodiment 1 The first embodiment of the tape cartridge according to the present invention will be explained with reference to Figs. 7 to 9. Referring to Fig. 7, a pair of particle entrance preventing walls 50 are formed at respective areas near a tape path regulating pin 9 and between the rear lid guide walls 5a and 5b and the respective left and right side edges 11a and 11b of the rear lid 11 to be projected from the respective rear lid guide walls 5a and 5b so as to close the respective clearances S therebetween for preventing entrance of the harmful floating particles into the inside of the cartridge case 1 through the clearances S. More specifically, as shown in Figs. 8 and 9, the particle entrance preventing wall 50 on the right side is continued to the bottom wall of the bottom case half 1b and is projected from the rear lid guide wall 5b to extend toward the pocket 5 between the opposed surfaces of the right side edge 11b of the rear lid 11 and the rear lid guide wall 5b. The particle entrance preventing wall 50 is adapted to extend from the front end of the bottom case half 1b in such a manner that the upper surface of the particle entrance preventing wall 50 is directly connected with the front surface of the bottom of the rear wall surface 19. The rear lid 11 has its right side part thereof extended a little longer than the rear lid of the conventional cartridge so that the right side edge 11b of the rear lid 11 is situated above the particle entrance preventing wall 50, thereby causing the clearance S defined between the opposed surfaces of the right side edge 11b and the surface of the rear guide wall 5b to be entirely closed by the particle entrance preventing wall 50 when viewed from below the pocket 5. In a similar manner, there is formed the particle entrance preventing wall 50 for the left side between the opposed surfaces of the left side edge 11a of the rear lid 11 and the rear lid guide wall 5a. In the arrangement mentioned above, it is possible to eliminate such a deficiency that the harmful floating particles in the air enter inside of the cartridge case 1 through the clearances S between the left and right side edges 11a, 11b of the rear lid 11 and rear lid guide walls 5a and 5b and the harmful particles adhere to the parts of the magnetic tape 2 opposing to the clearances S. The magnetic tape 2 is formed in such a manner that the magnetic layer made of metallic magnetic material is formed on one surface of the non magnetic substrate with a back coat layer formed on the other surface of the substrate. As the non magnetic substrate, there may be used a polyethylene terephthalate film, a polyimide film or a polysulfon film. As the metallic magnetic material, alloys of Fe, Co, Co-Ni, Co-Cr, Co-P, Co-Ni-P, Co-Ni-Fe, Co-Ni-Cr, Co-Fe, Co-Fe-Cr, Co-Fe-Ni, Co-Ti and Co-Cu. As the way of forming the magnetic layer, there may be used evaporation, sputtering, CVD method, ion plating and coating using binder. However, in the present invention, it is effective to form the magnetic layer using the any ways without the binder. There may be formed a protecting layer on the magnetic layer using lubricant agents and/or rust prevents. As the backcoating layer there may be used aliphatic compounds, fluorine compounds and silicon compounds. As the aliphatic lubricants, there may be used fatty acid, metal salt of fatty acid, ester of fatty acid, fatty acid amide and fatty acid alcohol. As the fluorine lubricants, there may be used trichlorofluoroethylene, perfluoroethylene, perfluoropolyether. perfluoroalkylpolyether, perfluoroalkylcarboxylate. As the silicone lubricants, there may be used silicone oil and modified silicone oil. As the hydrocarbon lubricants, there may be used paraffin, squlane and wax. It is possible to add the rust prevents with the lubricants for the backcoat layer. As the rust prevents, there may be used 2-pentylaminobenzimidazole, 2-mercaptobenzothiazole, sorbitan-monopalmitate, 5-methylbenzotriazole, 2-nitroso-1-naphtol, ferricyanate and ferrocyanate. Embodiment 2 Referring to Figs. 10 to 12 showing the second embodiment of the present invention, the difference between the first embodiment and second embodiment is in that in the first embodiment, the particle entrance preventing wall 50 is formed from the front end portion of the case body 1 to the bottom of the wall 19 so that the clearance S are closed over the entire length thereof in terms of the front to back direction of the case body 1, on the other hand, in the second embodiment, the particle entrance preventing wall 50 is projected from the rear lid guide walls 5a and 5b with such a small width member situated below only across the clearance S in such a manner that only the clearance S between the opposed surfaces of the lower portions of the side edge 11a or 11b of the rear lid 11 and the rear lid guide walls 5a or 5b is closed. In case only the respective clearances S between the opposed surfaces of the side edge 11a or 11b of the rear lid 11 and the rear lid guide wall 5a or 5b, there can be obtained the effect of preventing the corrosion of the lower edge of the magnetic tape 2. This is based on the fact that the corrosion of the magnetic tape 2 due to the floating harmful particles occur most remarkably at the lower edge portion 2a of the magnetic tape 2 which most adjacently faces to the clearances S. In the second embodiment, the lower portions of both of the left and right side edges 11a and 11b reach below the lower face of the particle entrance preventing wall 50 when the rear lid 11 is closed. In this case, of the the lower portions of both of the left and right side edges undesirably engage with the particle entrance preventing wall 50, there may be formed cut portions in both of the left and right side edges 11a and 11b to avoid the undesired engagement. Other embodiments In the first and second embodiments, the particle entrance preventing walls 50 are projected from the rear guide walls 5a and 5b of the case body 1. However, in the present invention, it is essential that the clearances S between both of the left and right side edges 11a and 11b of the rear lid 11 are closed by the particle entrance preventing wall 50, which may be projected from the rear lid 11 or may be projected from both of the case body 1 and rear lid 11. In the embodiments mentioned above, the particle preventing walls 50 are stationary, it may be arranged as movable members which are movable with the movement of the front lid or rear lid so long as the movable members close the clearances S when the front lid is in the closed position. Although the respective embodiments are employed in such tape cartridge that the rear lid 11 is moved in association with the front lid 6, the arrangement of the present invention may be applied to other types of a tape cartridge having a lid mechanism which the front lid and rear lid are moved independently.

Claims: A tape cartridge comprising case body (1) having a pair of tape drawing openings (4) defined on a front part of said case body, a magnetic tape (2) containing magnetic layer made of metallic material and lid means including a front lid (6) and a rear lid (11) assembled movably on said case body between a closed position and opened position for covering, when said tape cartridge is not in use, both faces of the magnetic tape (2) which is drawn out of the case body through the tape drawing openings (4) and extending along said front part of the case body, each of side ends (11a,11b) of said rear lid (11) opposing to each of inner faces of walls (5a,5b) of said case body (1) with clearance (S) therebetween, characterized in that said tape cartridge comprises particle entrance preventing means (50) for covering the clearance (S) when viewed from below the case body (1) so that said particle entrance preventing means (50) prevents entering of floating harmful particles into the area of the tape (2), said particle entrance preventing means (50) being positioned on the case body (1) in such a manner that it engages with the rear lid (11) only in the closed position of the rear lid.

Inventors: DOI TOSHIO, FUJIWARA HIDEO, ISOE NOBORU, MIZUTANI HIKARU, NIIMI HIDEAKI, WAKAI KUNIO, DOI, TOSHIO, FUJIWARA, HIDEO, ISOE, NOBORU, MIZUTANI, HIKARU, NIIMI, HIDEAKI, WAKAI, KUNIO
Applicants: HITACHI MAXELL, HITACHI MAXELL LTD.
Application year: 1988
Main classification: G11B23
IPC codes: G11B23