JPH01109584A - Magnetic disk cartridge - Google Patents

Abstract

PURPOSE:To reduce the occurrence of dropout without producing dust and to decrease the torque at the time of rotating a disk by providing a protruding part facing to a disk on the inner surface of either an upper half or a lower half. CONSTITUTION:An attracting yoke 24 is placed on a recessed part 5a around the center hole 8 of the lower half 5, and a disk 9 is so places so as to be brought into contact with the inner surface of the lower half 5. On the inner surface of the lower half 5, the plural pieces of ribs 5b small in height are integrally provided respectively in the radial direction of the disk 9 in areas excepting the opening 14 that is the area facing to the surface of the disk 9. Therefore, the disk 9 is placed on the ribs 5b, and the contacting area between the disk 9 and the lower half 9 becomes smaller. In rotation, the yoke 24 sticks to a driving spindle, a center hub 11 ascends, so that the disk 9 can easily come off the ribs 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a magnetic disk cartridge, and more particularly to a video flow 7 beaker lithography for electronic still cameras.

Conventional technology Electronic still cameras that magnetically record still images use small flexible magnetic disks.
For example, 25 or more still images can be recorded on one side of the disk by frame recording. These electronic still cameras have advantages over cameras using silver halide film, such as requiring no development, being reusable, and being easy to transmit.

FIG. 14 is an enlarged plan view of a conventional video floppy cartridge (hereinafter sometimes simply referred to as a cartridge), and FIG. 15 is an enlarged sectional view taken along the line XV--XV in FIG.

In this cartridge, an opening 14 is formed on both sides of a cartridge body 13 consisting of an upper half 4 and a lower half 5 made of plastic, and an internal floppy disk (hereinafter simply referred to as a disk) 9 faces into this opening 14. It is composed of The opening 14 is normally shielded by a metal shutter 6 having a U-shaped cross section when the disk is not in use, and the disk S is not exposed. During reproduction), the shutter 6 is moved to the imaginary line position, and the recording surface of the disk 9 is exposed through the opened opening 14. Note that the disk 9 is rotatably housed in the main body 13 while being fixed to a center hub 11 attached to a spindle on the driver side. On the surface of the upper half 4, an arrow mark 10 indicating the direction of loading the cartridge into the device is provided, and a recess 12 for attaching a label is provided. The main body 13 is provided with a central hole 7 through which the center hub 11 is exposed.

A recess 17 is provided on the right side of the shutter 6 in order to move the shutter 6 to the position shown by the dashed-dotted line during disk drive. It is designed to stop when it comes into contact with. The shutter 6, recess 17, protrusion 16, and wall surface 15 are located on the opposite side of the main body 13.

Such still video floppy cartridges are, for example, 2 inches, with dimensions 5.4 CIIX6, OC
It has the characteristics of being small, lightweight, and extremely thin at 11X0.36C11.

As shown in FIG. 15, a metal plate-shaped suction yoke 24 is fixed to the center hub 11, and when the disk rotates, the head of a spindle (not shown) fits into the center hub 11, and the suction yoke 24 becomes magnetic. The center hub 2 is fixed and supported by the spindle and separated from the main body 13. The upper and lower halves 4.5 are made of ABS resin (a copolymer of acrylonitrile, butadiene, and styrene) and are manufactured by injection molding.

The lower half 5 is provided with a recess 5a in a region facing the center hole 8 for fitting the spindle head, and a step is formed.
When the disk is not rotating, the suction yoke 24 fits into the recess 5a and is placed on the lower half 5 to prevent the disk 9 from being significantly displaced in the radial direction.

Further, as shown in FIG. 15, a cleaning member (called a liner sheet) 18 made of non-woven fabric and having a half-doughnut shape is attached to the peripheral edge of the inner surface of the lower half 5, and the cleaning member 18 is attached to the inner surface of the lower half 5 so that the disk 9 can be blown while the disk is rotating. It is designed to rub against the recording surface.

The rubbing of the disc 9 by the liner sheet 18 removes dust generated when the disc rotates, and also prevents the disc 9 from being charged. Further, there is also a cartridge in which a liner sheet 19 shown by a phantom line is provided between the upper half 4 and the disk 9 in the same manner as above.

It should be noted that there is a problem in that dust is generated from the liner sheet due to vibration during the cartridge assembly process and transportation, so various improvements have been made to the material of the liner sheet and the cartridge assembly process.

A non-woven fabric is used for the liner sheet to prevent the fibers from falling off and generating dust, but as a result of the inventor's studies, the fibers may fall off from the cut edges and other areas.
It has been found that this adheres to the disk and magnetic head, causing dropouts and causing damage to the disk and magnetic head.

In particular, in the case of a 2-inch cartridge, if the disk and liner sheet come into contact when the disk rotates, the torque increases, making it impossible for the liner sheet to rub against the disk, and the liner sheet vibrates, causing dust to be generated. This results in increased dropout.

C6 Purpose of the Invention The present invention has been made in view of the above circumstances, and includes:
The purpose of the present invention is to provide a magnetic disk cartridge that does not generate dust, significantly reduces dropout, and requires small torque when rotating the disk.

21 Structure of the Invention The first aspect of the present invention is that in a magnetic disk cartridge in which a magnetic disk is housed in a cartridge body consisting of upper and lower halves, the inner surface of at least one of the upper and lower halves has a The present invention relates to a magnetic disk cartridge characterized in that a protrusion is provided facing the surface of the magnetic disk.

A second aspect of the present invention is a magnetic disk cartridge in which a magnetic disk is housed in a cartridge body consisting of upper and lower halves, in which an inner surface of at least one of the upper and lower halves faces the surface of the magnetic disk. an antistatic substance is applied thereto, and the antistatic substance is contained in at least an inner surface area of the at least one half facing the surface of the magnetic disk. The present invention relates to a magnetic disk cartridge characterized by:

E, Example The present invention will be explained in detail below.

Fig. 4 is an enlarged plan view of the cartridge seen from the upper half side, Fig. 5 is a bottom view of the cartridge seen from the lower half side,
FIG. 3 is an enlarged sectional view taken along line mm in FIG. 4.

The structure of the cassette body 3 is the same as that shown in FIGS. 14 and 15 described above, so detailed explanation will be omitted. In addition, parts common to FIGS. 14 and 15 are denoted by the same reference numerals.

The disk 9 is attached to a center hub 11, and a metal suction yoke Z4 is provided below the center hub 11. The function of the suction yoke 24 will be explained later with reference to FIG.

The suction yoke 24 is attached to the recess 5 around the center hole 8 of the lower half 5.
The upper and lower halves 4.5 are not provided with liner sheets, and the disk 9 is placed in contact with the inner surface of the lower half 5. What should be noted here is that, as shown in FIG. (7 in this example)
The ribs 5b having a very small height are integrally provided in a radial manner. Therefore, the disk 9 is placed on the seven ribs 5b, and the contact area between the disk 9 and the lower half 5 is small. It is effective to make the height of the rib 5b quite high so that it does not come into contact with the half when the disk rotates, in order to prevent sticking, which will be described later. When the disk rotates, the suction yoke 24 attracts the drive spindle, the hub 11 rises, and the disk 9 easily separates from the rib 5b.

FIG. 1 is an exploded perspective view of each part constituting the cartridge.

The disk 9 is sandwiched at its center between a plastic core 22 into which a metal suction yoke 24 is fitted and a plastic upper ring 27 into which the core 22 is fitted, and is also covered with double-sided tape 2.
6 to fix it to the suction yoke 24. Upper ring 27
In the figure, a disk 9 is attached to a drive spindle (not shown).
A leaf spring 28 for positioning in the radial direction is fitted so as to protrude from the inner peripheral surface. The upper ring 27, leaf spring 28, core 22, and suction yoke 24 constitute a hub (11 in FIGS. 3 and 4). The above components are attached to the disk 9, which is housed between the upper half 4 and the lower half 5 to which the shutter stopper 20 is attached, and the shutter 6 is fitted to complete the cartridge.

FIG. 6 is an enlarged partial sectional view of the cartridge when the disk is rotating.

A central protrusion 31 of a spindle 30 made of a magnetic material is inserted into a central through hole of the hub 11 via a central hole 8 of the lower half 5. An annular protrusion 32 is provided on the spindle 30 so as to surround a central protrusion 31.
comes into contact with the suction yoke 24 and pushes it up slightly to separate it from the inner surface of the lower half 5. A plastic lower ring 25 is fixed to the lower side of the suction yoke 24.
An annular projection 32 of the spindle 30 abuts the suction yoke 24 in the region between the core 22 and the lower ring 25 . The lower ring 25 enters into a groove connecting small through-holes locally provided in several places in the suction yoke 24, and is fixed to the suction yoke 24 by the intrusion portions 25a. The attraction yoke 24 attracts the magnetic annular protrusion 32 of the spindle 30, and the disk 9 is stably supported by the spindle 30 via the hub 11. The central projection 31 of the spindle 30 presses against the leaf spring 28 and radial positioning of the hub 11 and thus of the disc 9 is effected.

In this state, as the disk 9 rotates due to the rotation of the spindle 30, the shutter 6 shown in FIGS. 4 and 5 moves to expose the opening 14, and the magnetic head (not shown) comes into sliding contact with the disk 9 to perform recording or recording. Regeneration is performed.

The vibration during rotation of the recording surface (lower surface) of the disk 9 is 1. .355
The distance is set to ~2.230+nm. If the disk 9 shakes outside this range, good recording and reproduction will not be possible. In this example, the thickness t of the lower half 5 is 1.
It is set to 1 mm. Therefore, by doing the above, when the disk rotates, the hub 11 is pushed up by the spindle 30 as described above, so the recording surface of the disk 9 does not come into contact with the inner surface of the lower half 5 (the disk 9 It also does not come into contact with the inner surface of the upper half 4.)

In this way, there is no cause of dust generation when the disk rotates.
Further, the recording surface of the disk and the magnetic head are not scratched, dropouts are effectively prevented, and good recording and reproduction can be performed. In addition, there is no liner sheet provided on the lower half, and the disc 9 has a small contact area with the rib 5b.
Since the disc 9 is placed on top of the rib 5 during startup, the disc 9
b. Therefore, the torque at the time of starting does not become large, and the number of parts is reduced, and manufacturing costs are also reduced.

Further, when the cassette body is made transparent, there is no liner sheet, so it does not become an eyesore and is convenient in terms of appearance.

1000 cartridges (Example 1) shown in Figures 1 to 6
A vibration resistance test was conducted on these sheets to determine whether or not dropouts occurred. However, in this example, ribs are provided on both the upper and lower halves.

The vibration resistance test was conducted using the following method. i.e., for each cartridge, amplitude 10 cm, 200 cycles/lll
Vibration is applied in the 1n, X, and Z directions for 3 hours, respectively.

The occurrence of dropout was investigated as follows. When the region in which the output during reproduction decreases by 12 dB or more is 10 μsec or more, dropout is determined to have occurred, and a cartridge in which no dropout occurs is determined to be a passed product.

The results are shown in the table below. For comparison, the table shows cartridges shown in FIGS. 14 and 15 (conventional The results of a similar test conducted on a cartridge (Comparative Example 2) and a cartridge (Comparative Example 1) manufactured in the same manner as in Example 1 but without the rib 5b are also shown. In addition, Example 2 described in the table
and 3 will be detailed later. Examples 1.2 and 3
In both Comparative Examples 1 and 2, the presence or absence of dropout was examined before the vibration resistance test, and 1000 sheets without dropout were selected and subjected to the test.

From the above results, the conventional cartridge (Comparative Example 2)
In some cases, dust is generated from the liner sheet during the assembly process, causing dropouts to occur before the test, and even in cases where dropouts were not in a condition to occur, more than 10% of dropouts occurred after vibration proof M. is occurring. In contrast, in Example 1 and Comparative Example 1, the phenomenon that causes dropouts does not occur during cartridge assembly, and furthermore, they withstand vibration well, effectively prevent dropouts, and always provide good recording. It can be understood that regeneration is carried out.

For 100 cartridges each of Example 1 and Comparative Example 1, the magnitude of torque at the time of starting the disk rotation was examined. The magnitude of torque is expressed by the current consumption of the motor using the following formula. However, only one trunk is measured.

Motor consumption current = voltage 10.67Ω The results are shown in bar graphs, with Example 1 shown in Figure 7 and Comparative Example 1 shown in Figure 1.
As shown in Figure 3.

As can be seen from FIGS. 7 and 13, the average starting torque in Example 1 is smaller than that in Comparative Example 1, and the variation is also smaller. This is because in Example 1, the disk 3 is in contact with the rib 5b and the contact area is small, whereas in Comparative Example 1, since no rib is provided, the disk 9 has a large area on the inner surface of the lower half 5. This is due to contact. It is considered that the five disks that showed 97.0 mA in Comparative Example 1 had their disks stuck to the inner surface of the lower half and required a particularly large torque at the time of starting.

As described above, in Example 1, by not providing a liner sheet, there is no cause of dust generation due to vibration etc., and the occurrence of dropouts is significantly reduced. By providing opposing protrusions (radial ribs 5b in this example), the contact area between the disc and the lower half is small (the torque required when starting the disc is small, and the disc rotates at a predetermined speed quickly after starting). and good recording and playback performance is always achieved.

In addition to the radial ribs 5b shown in FIG. 2, the ribs of the lower half include a plurality of annular ribs 5c on concentric circles and a plurality of linear ribs parallel to each other, as shown in FIG. It is also possible to provide a rib 5d, a plurality of dot-like protrusions 5e arranged radially, or a plurality of dot-like protrusions 5f arranged randomly. However, if the disk is slightly curled, It is preferable to provide ribs or protrusions such as (C1, (dl).

Embodiment 1 described above is an example in which a protrusion (rib) is provided on the inner surface of the half so as to face the surface of the disk, but instead of this, an antistatic substance may be applied to the inner surface of the half, or an antistatic substance may be applied to the inner surface of the half. By containing it, the same effects as in Example 1 can be achieved. These examples will be described below.

Since the half is made of resin such as ABS resin, it has a high surface resistivity, so it comes into contact with the disk and becomes electrically charged, causing the disk to stick to the half and increase the torque when starting rotation. By preventing this charging, the above problem is solved.

As shown in FIG. 9, the lower half 5 was not provided with any protrusions such as ribs, and a coating layer 5g coated with an antistatic agent was applied to the area facing the surface of the disk (not shown) (Example 2).

Examples of the antistatic agent include various surfactants and inorganic fillers.

The surfactants used include carboxylic acid compounds (e.g. adipic acid, glutaric acid, styrene-maleic acid copolymer potassium salt), guanidine derivatives (phenylguanidine derivatives, etc.), phosphate-containing anion surfactants (e.g. alkyl phosphorus), acid esters, polyphosphates, alkyl phosphate ester metal salts, etc. Examples include β-(β-
ethoxy)-dioxane dialkyl phosphate metal salts, pentaalkyl triphosphates, hexaalkyl tetrabolyphosphates, etc.), sulfonic acids (e.g. orgostyrene sulfonic acid, alkylaryl sulfonic acid, triethanolamine salt of polystyrene sulfonic acid)
Anionic activators such as No. 477-T-, :, rum salt (
(CI?H3SCONH(CHI)ffN(CH3)Z
CtHaOH)NOs' etc.), pyridinium salts, imidacillin derivatives, morpholine derivatives, polyethylene glycol nonionic activators such as polyoxyethylene-alkylphenols and alkylamidoethers,
There are also sorbitan fatty acid esters. Also, polymers such as acrylic acid, methacrylic acid, and acids that have functional groups (formula below)
It also provides antistatic properties.

In addition, fatty acid amides and fatty acid amines are surface active (R:
H, CHs i R+, Rz, Rs: alkyl group; X: acid group) It can also be used in combination with an agent. In particular, ammonium salt type,
Compounds containing phosphoric acid residues are preferred; examples of inorganic fillers include copper chloride, calcium fluoride, various metal salts, Ca,
Examples include oxides of Mg, Zn, Ti, Fe, etc., kaolin, sodium-aminosilicate, calcium silicate, and the like. These warm, conductive carbon blanks
It is effective in preventing static electricity and can be used.

A paint made of the above antistatic agent is applied to the area of the lower half 5 and dried to form a coating layer of 5 g. In this example, the above-mentioned polyethylene glycol nonionic activator was used as the antistatic agent.

A cartridge was manufactured using this lower half (as shown in FIG. 9), and the vibration resistance test and the magnitude of torque (current consumption) at the time of starting the disk were measured in the same manner as in Example 1.

The results of the vibration resistance test are also listed in the table above. The magnitude of the torque mentioned above is as shown by the bar graph in FIG. In all cases, good results approximately equivalent to those of Example 1 were obtained.

FIG. 11 is an enlarged partial sectional view of the lower half 5 containing an antistatic agent 5h.

When molding the lower half, the antistatic agent used in Example 2 was mixed with the molding material to form the lower half 5 in FIG. 11 (Example 3). In addition to the ABS resin of this example, styrene resins such as polystyrene, AS resin (acrylic-styrene copolymer), and conductive carbon black can be preferably used as the resin for dispersing the resin.

The antistatic agent content in the half is preferably within the range of 0.1% to 0.8% by weight of these styrene resins, and preferably within the range of 0.2% to 0.5% by weight. (For example, 0.4% by weight) is more preferable. If the content of the antistatic agent is less than the above range, the antistatic effect will not be significant, and if it is more than the above range, the strength of the styrene resin will tend to decrease. In this example, conductive carbon black is 0.
It is bound at 4% by weight.

A cartridge was manufactured using this lower half (as shown in FIG. 11), and the vibration resistance test and the magnitude of torque (current consumption) at the time of starting the disk were measured in the same manner as in Example 1.

The results of the vibration resistance test are also listed in the table above. The magnitude of the torque mentioned above is as shown in the bar graph in FIG. In both cases, good results approximately equivalent to those of Example 1.2 were obtained.

Although the present invention has been described in detail above, the protrusions such as ribs of the first embodiment may be provided on both the upper and lower halves, or may be provided on either the lower half or the upper half. Also,
The half provided with the coating layer of the antistatic substance of Example 2.3 or the half containing the antistatic substance r may be either the lower half, the upper half, or both.

As described in detail in Section 6 of the invention, the first invention of the present invention provides a protrusion on the inner surface of at least one of the upper and lower halves to face the surface of the magnetic disk, thereby preventing the magnetic disk from rotating. Sometimes the magnetic disk is in contact with the protrusion and the contact area is small. The second aspect of the present invention is that a coating layer of an antistatic substance is provided or is contained in a small area of the upper and lower halves (both of which face the surface of the magnetic disk on the inner surface of one half). As a result, in both the first and second inventions, the attraction force due to static electricity between the half and the magnetic disk is small, and dust is not generated inside the cassette body due to vibration etc., which can cause dropouts. Furthermore, the torque required when starting the rotation of the magnetic disk is small, and rotation at a predetermined speed can be quickly achieved at the time of starting, so that good recording and reproduction are always performed.

[Brief explanation of the drawing]

Figures 1 to 12 show embodiments of the present invention. 1 - An exploded perspective view of a magnetic disk cartridge. 2 - An enlarged plan view of the lower half. 3 - An enlarged view of the magnetic disk. 4 is an enlarged plan view of the magnetic disk cartridge, 5 is an enlarged bottom view of the magnetic disk cartridge, and 6 is an enlarged sectional view of the magnetic disk cartridge during drive. Fig. 7 is a graph showing the frequency distribution of current consumption when starting a magnetic disk; Fig. 8 is an enlarged sectional view of the lower half of another example; Fig. 10 is a magnetic diagram of another example. A graph showing the frequency distribution of current consumption when starting a disk, FIG. 11 is an enlarged partial sectional view of the lower half according to another example, and FIG. 12 shows a frequency distribution of current consumption when starting a magnetic disk according to still another example. This is a graph showing. FIG. 13 is a graph showing the frequency distribution of current consumption when starting the magnetic disk of a comparative magnetic disk cartridge. 14 and 15 show a conventional example. FIG. 14 is an enlarged plan view of a magnetic disk cartridge, and FIG. 15 is an enlarged sectional view taken along the line xv-xv in FIG. 14. In addition, in the reference numerals shown in the drawings, 3.--.--m--.--.
−−−−−〜−・・−・Upper half 5−−−−−−1−
~-Lower half 5b, 5c, 5d---------Rip 5
e, 5f--・---------point-like protrusion 5g--
−1−−−・−・Antistatic substance coating layer 5h−・−・・−
11---Antistatic substance 9・-・---------・-・
Magnetic disk 11---------・------ Center hub 22--- Core 24・-111---Suction yoke 30・-
-------.-Spindle 31------------- Center protrusion 32 of the spindle -1--This is an annular protrusion of the spindle. Agent Patent Attorney Hiroshi Aisaka Figure 3'' ■ Figure 6 Figure 8 Figure 8 Figure 8 Figure 14 Figure 15

Claims (1)

[Scope of Claims] 1. In a magnetic disk cartridge in which a magnetic disk is housed in a cartridge main body consisting of upper and lower halves, an inner surface of at least one of the upper and lower halves faces the surface of the magnetic disk. A magnetic disk cartridge characterized by being provided with a protrusion. 2. In a magnetic disk cartridge in which a magnetic disk is housed in a cartridge body consisting of upper and lower halves, an antistatic substance is coated on the inner surface of at least one of the upper and lower halves facing the surface of the magnetic disk. and the antistatic substance is contained in at least an inner surface area of the at least one half facing the surface of the magnetic disk. disc cartridge.