Welding pattern for a cleaner liner in a magnetic disk cartridge

A magnetic disk cartridge has a case on which a transducer access rectangular opening is formed, a magnetic disk accommodated in the case, and liners partly welded to the inner surfaces of the case in order to clean the surfaces of the magnetic disk. The magnetic disk cartridge is characterized in that the liners are welded to the inner surfaces of the case through a welding pattern. The welding pattern comprises a discontinuous line extending along the edge of the liner and a straight line intersecting with the discontinuous line but not extending to overlay the effective magnetic recording area.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a magnetic disk cartridge and particularly to a 
welding pattern of cleaning liners to the inner surfaces of a case. 
2. Description of the Prior Art 
A conventional welding pattern of cleaning liners in a magnetic disk 
cartridge will be described with reference to FIGS. 5 to 7. 
As shown in FIG. 5, the magnetic disk cartridge includes a case 1 
comprising a bottom member 11 and a cover member 12 and a magnetic disk 
rotatably disposed within the case 1. And liner 2, 2 (cf. FIGS. 6 and 7) 
for cleaning the surfaces of said magnetic disk are attached to the 
respective inner surfaces of the bottom member 11 and the cover member 12. 
The liners 2, 2 are attached to the respective members in the same welding 
pattern. 4 is a shutter. 
The welding pattern of the liners 2, 2 against the respective inner 
surfaces of the bottom member 11 and the cover member 12 in the 
conventional magnetic disk cartridge will be concretely described 
hereinafter. However, as the liner 2 is attached against both members 11 
and 12 in the same welding pattern as mentioned above, only the welding 
pattern of liner 2 against the bottom member 11 will be described and the 
welding pattern of liner 2 against cover member 12 will be omitted. 
As shown in FIGS. 6 and 7, the bottom member 11 is provided with a hub 
access central opening 11A formed in its center and a transducer (not 
shown) access rectangular opening 11B formed in adjacent to the central 
opening 11A. 
A liner 2 formed from a nonwoven fabric surrounding the central opening 11A 
is attached to a part of the inner surface of the bottom member 11 by 
heating, supersonic wave or the like. The liner 2 is cut out at a portion 
corresponding to the opening 11B and therefore has a generally C-shaped 
configuration. The liner 2 has a width enough for cleaning the surface of 
the magnetic disk. Both the upper and lower surfaces of the magnetic disk 
are covered with and sandwiched by the liners 2, 2 of the both members. As 
shown in FIGS. 6 and 7, only the inner surface of the bottom member 11 is 
attached with the press member 3 formed from a plastic sheet and covered 
by the liner 2. 
The liner 2 has a welding area formed in the vicinity of its edge and 
partly welded. In the welding area, as is shown in FIG. 6, liner welding 
portions 2A directing toward the inner side of the liner 2 are formed at a 
generally equal distance along the edge. 
Accordingly, as the liner 2 is welded to the inner surface of the bottom 
member 11 only at its edge portions, the central portion of the liner 2 is 
protruded. The magnetic disk contained in the case 1 is cleaned by this 
protuberance during reproducing and recording. 
However, the conventional magnetic disk cartridge has a shortcoming in that 
the welding area of the liner 2 with respect to the case 1 reaches to an 
effective magnetic recording area of the magnetic disk and the effect of 
cleaning is sometimes decreased at this portion. Also, fins are sometimes 
formed in the welding portion 2A by the welding process. At that time, the 
effective magnetic recording area is sometimes damaged by contact with the 
fins. In order to prevent the occurrence of such damage as much a 
possible, there is a method in which each of the straight lines of the 
welding portion 2A is made short to form a narrow welding area. However, 
according to this method, there is such a fear as that the welding 
strength of the liner 2 with respect to the inner surface of the case 1 is 
reduced such that the liner 2 is apt to turn up during recording and 
reproducing of the magnetic disk. When the liner is turned up, the contact 
resistance between the liner and the magnetic disk becomes large and the 
rotational torque of the magnetic disk can fluctuate. In some instances, 
the liner 2 is fluffed due to friction between the liner 2 and the 
magnetic disk and fibers of the liner 2, i.e., nonwoven fiber fall out and 
stick to the surface of the magnetic disk. This causes a bad effect on the 
magnetic disk during recording and reproducing. 
SUMMARY OF THE INVENTION 
It is therefore the general object of the present invention to provide a 
magnetic disk cartridge in which the liners can be welded to both inner 
surfaces of the case (inner surfaces of bottom member 11 and cover member 
12) with a sufficient strength such that the magnetic disk can effectively 
be cleaned by the liners without damaging the effective magnetic recording 
area. 
The object of the present invention can be achieved by providing a magnetic 
disk cartridge including a case, a magnetic disk accommodated in said 
case, and a liner partly welded to each of the inner surfaces of said case 
for cleaning the surfaces of said magnetic disk, said magnetic disk 
cartridge being characterized in that said liners are welded to the inner 
surfaces of said case through a welding pattern comprising a discontinuous 
line extending along the edge of said liner and a straight line 
intersecting with said discontinuous line which do not reach to the 
effective magnetic recording area. 
According to the magnetic disk cartridge of the present invention, as the 
liner is welded to the case through the welding pattern comprising a 
discontinuous line extending along the edge of the liner and a straight 
line intersecting with the discontinuous line which do not reach to the 
effective magnetic recording area of the magnetic disk, the liner can be 
welded to the case with sufficient strength. Accordingly, the protuberance 
of the liner is surely contacted with the entire effective magnetic 
recording area and the magnetic disk can be cleaned by the liner without 
damaging magnetic recording layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The gist of the features of the present invention will be described 
hereinafter with reference to the embodiments illustrated in FIGS. 1 
through 4, wherein identical and similar parts are denoted by identical 
reference numerals. 
The magnetic disk cartridge of the present invention, like the conventional 
magnetic disk cartridge, includes a case 1 provided with a transducer 
access rectangular opening, a magnetic disk accommodated in said case 1 
and a liner 2 partly welded to the inner surface of said case 1 and 
adapted to clean the surface of said magnetic disk. However, the magnetic 
disk cartridge of the present invention is different from the conventional 
one in welding pattern of the liner 2 against the both inner surfaces of 
bottom member 11 and cover member 12 forming the case 1. 
Therefore, only the welding pattern of the liner 2 against the both inner 
surfaces of the case 1 of the magnetic disk cartridge of the present 
invention will be described. Further, only the welding pattern of the 
liner 2 against the bottom member 11 will be described hereinafter, 
because the welding pattern of the liner 2 against the cover member 12 is 
performed in the same welding pattern as against the member 11. 
A liner 2 of a magnetic disk cartridge of this embodiment, as shown in FIG. 
1, is welded to the inner surface of the bottom member 11 through a 
welding pattern P which comprises a discontinuous line 2A extending along 
the edge of the liner 2 and a straight line 2B intersecting with the 
discontinuous line which does not reach to the effective magnetic 
recording area of the magnetic disk. 
That is, the edge of the liner 2 is welded through the discontinuous line 
2A, and the welding strength of the discontinuous line 2A is reinforced by 
means of welding of the straight line 2B intersecting with each component 
element line of the discontinuous line 2A. The straight line 2B, as 
apparent from FIG. 1, is generally perpendicular to each discontinuous 
line 2A at its center to form a T-shape configuration. In addition, the 
straight line 2B is sufficiently short as not to reach to the effective 
magnetic recording area of the magnetic disk. 
Therefore, according to the magnetic disk cartridge of the present 
invention, as the welding pattern P does not reach to the effective 
magnetic recording area of the magnetic disk, when, if fins are generated 
when the liner 2 is welded to the case 1, the fins will never touch the 
effective magnetic recording area of the magnetic disk. As a consequence, 
the effective magnetic recording area is not damaged by the fins. 
Moreover, the welding portion of the welding pattern P is formed in a 
narrow range adjacent to a nonrecording portion of the magnetic disk in 
such a manner as to have a sufficient welding strength and the liner 2 is 
effectively protruded over the entire effective magnetic recording area. 
As a consequence, the liner 2 can exhibit an excellent cleaning 
performance. That is, according to the magnetic disk cartridge of this 
embodiment, the liner 2 holds a sufficient welding strength with respect 
to the case 1, namely the inner surface each of the bottom member 11 and 
the cover member 12, and can effectively clean the magnetic disk without 
damaging the magnetic disk. 
Similarly, a magnetic disk cartridge of a second embodiment according to 
the present invention, as shown in FIG. 2, has a welding pattern P 
comprising a discontinuous line 2A and a straight line 2B intersecting 
with the line 2A as in the magnetic disk cartridge of the preceding 
embodiment. In this second embodiment, different from the preceding 
embodiment, the straight line 2B extends in a general vertical direction 
from one end of each line 2A to form as L-shaped configuration. 
Accordingly, the same technical effect to that of the preceding embodiment 
can be expected on this embodiment. 
A third embodiment of a magnetic disk cartridge of the present invention, 
as shown in FIG. 3, is constructed as such that only a welding pattern P' 
in a welding area at an edge portion (the edge portion along the 
transducer access opening 11B) for intercommunication an internal edge 
portion and an external edge portion of the liner 2 is formed of a 
plurality of slant lines 2C arranged in parallel relation with each other. 
The welding pattern P at the external and internal edge portions of the 
liner 2 excluding the intercommunicating edge portion is formed in the 
same manner as the welding pattern P of the first embodiment. 
A fourth embodiment of the present invention, as shown in FIG. 4, is 
constructed as such that a welding pattern P' in a welding area at an edge 
portion for intercommunicating an internal edge portion and an external 
edge portion of the liner 2 is formed of a plurality of slant lines 2C 
arranged in parallel relation with each other as in the case with the 
third embodiment, and a welding pattern P at the internal and external 
intercommunicating edge portions excluding the edge portion is formed in 
the same manner as the welding pattern P of the second embodiment. A part 
of the welding pattern P' formed of the slant lines 2C may be disposed at 
the internal edge of the liner 2 as shown in FIG. 4. 
The same technical effect as that of the first and second embodiment can be 
expected on the magnetic disk cartridges of the third and fourth 
embodiments. 
In the above-mentioned various embodiments, the straight line 2B may be 
directed outwardly from each line of the discontinuous line 2A. 
Furthermore, in the above-mentioned various embodiments, the intersecting 
modes of the straight line 2B were generally perpendicular to each line of 
the discontinuous line 2A. However, it goes without saying that the 
pattern P may be formed such that the straight line is disposed at angles 
with respect to each line of the discontinuous line 2A, or a plurality of 
straight lines 2B are formed with respect to one line. 
Although the present invention is mainly applicable to a 3.5 inches or 
smaller size magnetic disk cartridge, the size of the magnetic disk 
cartridge is not limited as long as it is not against the spirit of the 
present invention.