Recording apparatus for magneto-optical disc

Abstract: The present invention provides a magneto-optical disc recording apparatus for writing information signals on a disc in which an external magnetic field generator is moved in close to the disc after commencement of the rotation of the disc and is moved away from the disc before stopping of the rotation of the disc so that so called sticking of the external magnetic field generator to the disc is prevented.

Description: The present invention relates to a magneto-optical disc recording apparatus for recording information signals upon a magneto-optical disc housed in a cartridge, said apparatus including a mechanism for controlling the movement for an external magnetic field generator toward and away from said disc in association with the commencement and stopping of the rotation of the magneto-optical disc loaded in the disc loading portion. US-A-4,736,263 describes a magnetic disk drive apparatus which moves the read-write head towards and away from the disk by means of a solenoid acting through a lever. The solenoid is controlled such that the head is brought into contact with the disk only after commencement of rotation and is separated from the disk before cessation of rotation. Magneto-optical discs including a signal recording layer in which so called perpendicular magnetization is possible have been proposed. In order to record information signals on the magneto-optical disc, an area of the signal recording layer on which information signals are recorded is heated to a temperature not less than the Curie temperature by focusing a laser beam and irradiating it thereto and an external magnetic field is applied to this area. Since the signal recording layer which has been heated to a temperature not less than Curie temperature substantially loses its coercive force, the magnetization direction is reversed along the line of the external magnetic field. By reversing the magnetization direction of the signal recording layer in such a manner, recording of digital information signals can be performed. A magneto-optical disc recording apparatus which writes information signals on such a magneto-optical disc, comprises a rotary driving device which holds and rotates the magneto-optical disc, an optical pick-up device for irradiating the signal recording layer of the magneto-optical disc with a laser beam and an external magnetic field generator which applies an external magnetic field upon the signal recording layer. In the above mentioned magneto-optical disc recording apparatus, some external magnetic field generators include so-called flying magnetic head. The flying magnetic head is biased in such a direction that it is moved toward the rotating magneto-optical disc. The flying magnetic head comprises a core and a coil for generating a magnetic field which is wound and housed in the core. The core of the flying magnetic head is formed in such manner that the head is moved in close to the magneto-optical disc to form a very small air gap therebetween due to a fact that air entrained between the core and the rotating magneto-optical disc forms an air film. The core of such a flying magnetic head is finished to a smooth plain face on the side facing the magneto-optical disc so that the air film is formed in a desirable manner. Therefore, if the flying magnetic head is brought into contact with the magneto-optical disc which is stationary, there is the possibility that the magneto-optical disc and the flying magnetic head would be damaged. In the above mentioned disc recording apparatus, some external magnetic field generators are supported by a rotatable arm in order that they are movable toward and away from the disc. In such a magneto-optical disc recording apparatus, it is necessary to rotate the arm over a sufficient angle to separate the external magnetic field generator from the disc by such a distance that loading, unloading and eject operation of the disc will not be difficult when these operation is performed. If the rotating angle of the arm is increased, the apparatus becomes complicated in structure and miniaturization of the apparatus becomes difficult. If a magneto-optical disc housed in the cartridge is used in the magneto-optical disc recording apparatus in which the external magnetic field generator is supported on the rotatable arm as mentioned above, there is the possibility that the arm will contact with the edge of the cartridge when the external magnetic field generator is tried to move in sufficiently close to the disc. If the arm is brought into contact with the edge of the cartridge, excellent recording of information signals cannot be performed. According to the present invention, there is provided a recording apparatus for magneto-optical disc comprises: a cartridge holder which is moveable toward and away from a chassis; a lifter which is moveable to follow the cartridge holder; an external magnetic field generator which is supported so that it is moveable toward and away from the chassis and is supported in a position separated from a magneto-optical disc of a disc cartridge loaded on the cartridge holder by the lifter; and further comprising: control means which is operative to move the external magnetic field generator toward the magneto-optical disc via the lifter after commencement of the rotation of the magneto-optical disc and to move the external magnetic field generator away from the magneto-optical disc via the lifter before stopping of the rotation of the magneto-optical disc. The present invention may provide a recording apparatus for a magneto-optical disc in which so called sticking of the external magnetic field generator to the magneto-optical disc is prevented even if so called flying magnetic head is used as an external magnetic field generator. In the recording apparatus of a disc in accordance with the present invention the outer magnetic field generator may be mounted on a projection provided on one side of a rotatable arm facing disc. Since the external magnetic is moved via the lifter by control means in a disc recording apparatus of the present invention in such a direction that it approaches to the disc after the commencement of the rotation of the disc and is moved away from the disc before stopping of the rotation of the disc, the external magnetic field generator will not contact with the stopped disc. The external magnetic field generator is supported on the rotatable arm so that it can be moved toward and away from the magneto-optical disc and is moveable in a radial direction of the disc together with the arm. The external magnetic field generator is moved in an outer radial direction of the disc when the disc is unloaded. Therefore, the external magnetic field generator is located in the outer peripheral side of the disc when the disc is ejected for discharge. Further when the external magnetic field generator is mounted on a projection of the rotatable arm on the side facing the disc in the above mentioned disc recording apparatus, the arm is separated from the disc even under a condition that the external magnetic field generator is substantially contacted with the disc. The misinsertion detection portion of the misinsertion detection member of the disc cartridge misinsertion preventing mechanism is prevented from being engaged with the recess since it is made wider than the opening width of the recess formed on one side at which the notch for determining the direction of the insertion of the disc cartridge into the cartridge holder is formed. The invention will be further described by way of non-liimitative example with reference to the accompanying drawings, in which:- Figure 1 is a perspective view showing a cartridge holder including a conventional misinsertion and a magneto-optical disc cartridge which will be inserted into the cartridge holder; Figure 2 is a perspective view showing the lower surface of the disc cartridge; Figure 3 is an exploded perspective view showing the structure of a magneto-optical disc recording apparatus of the present invention; Fig. 4 is a perspective view showing a cartridge holder including a misinsertion detection mechanism in accordance with the present invention and a magneto-optical disc cartridge which is inserted into the cartridge holder; Fig. 5 is an enlarged perspective view showing a misinsertion preventing lever forming the misinsertion detection mechanism; Fig.6 is a plan view showing the cartridge holder in which a magnetic disc cartridge not to be inserted is inserted; Fig. 7 is an enlarged plan view showing the main part thereof; Fig. 8 is an enlarged longitudinal sectional view showing the structure of the disc recording apparatus; Fig. 9 is an enlarged longitudinal sectional view showing a condition that a disc cartridge of the disc recording apparatus is mounted; Fig. 10 is an enlarged longitudinal sectional view showing a condition that the disc of the magneto-optical disc recording apparatus is rotated; Fig.11 is an enlarged plan view showing the structure of an main part of the disc recording apparatus; Fig. 12 is an enlarged plan view showing the structure of the main part of the disc recording apparatus in which eject operation is performed; Fig. 13 is an enlarged perspective view showing the structure of a flying magnetic arm and a support arm which form the disc recording apparatus; and Fig. 14 is an enlarged perspective view showing the other example of the flying magnetic head and the support arm. Detailed embodiment of the present invention will be hereafter described with reference to drawings. The disc cartridge which houses the magneto-optical disc and is used for this type of magneto-optical disc recording apparatus is formed as shown in figures 1 and 2 of the accompanying drawings. The disc cartridge 101 comprises a square main cartridge body 102 which is formed by abutting upper and lower halves 102a and 102b so that they are engaged with each other and a magneto-optical disc 103 which is rotatably housed in the main cartridge body 102 as shown in Figs. 1 and 2. A magnetic head opening 104 and an optical head opening 105 are provided in a position which is middle in a lateral direction of the upper and lower halves 102a and 102b, respectively, which form a main cartridge body 102 in which the magneto-optical disc 103 is housed and is offset to the front side of the main cartridge body 102. A part of the signal recording surface of the magneto-optical disc 103 is exposed to the outside in a radial direction through these openings 104 and 105. A magnetic head for generating an external magnetic field and an optical head are disposed on the side of a recording apparatus for recording desired information signals on the disc 103 to face it through these openings. An opening 106 for a disc table into which the disc table of a disc rotating drive apparatus provided on the side of the recording apparatus for rotating the magneto-optical disc 103 is provided in the substantial center of the lower half 102b so that the opening 106 is continuous to the optical head opening 105. A shutter 107 which opens and closes each of the openings 104, 105 and 107 is movably mounted on the main cartridge body 102 so that dust and the like will be prevented from penetrating into the main cartridge body 102 through the magnetic head opening 104, the optical head opening 105 and the disc table opening 106 and from contaminating and damaging at least the signal recording surface of the optical disc 103 housed in the main cartridge body 102. The shutter 107 is formed by bending a thin metal plate into a π shape in section and is mounted on the main cartridge body 102 from the front side thereof to cover the opening 104, 105 and 106 with a pair of upper and lower covering plates 107a and 107b, respectively. The shutter 107 is biased by a shutter closing spring 8 to normally close the openings 104, 105 and 106 when the disc cartridge is not loaded on the recording and/or playback apparatus and is not used. The disc cartridge 101 is provided with the magnetic head opening 104 and the optical head opening 105 which the external magnetic field generating magnetic head and the optical head face, respectively in a position offset to the front side of the main cartridge body 102 as mentioned above. Accordingly, the direction of loading of the disc cartridge 101 to the cartridge loading portion in the recording and/or playback apparatus is determined in order to align the external magnetic field generating head and the optical head with the magnetic head opening 104 and the optical head opening 105. Such a type of the disc cartridge 101 is provided with a notch 109 for determining the direction of insertion into the cartridge holder 121 when the disc cartridge 101 is loaded on the cartridge loading portion by using the cartridge loading apparatus having the cartridge holder 121 shown in Figs. 1 and 2. The notch 109 is formed by notching a corner on one side and front face on which the shutter 107 of the main cartridge body 102 is mounted so that the corner is inclined. The shape of the substantially square disc cartridge 101 will become asymmetric in lateral and longitudinal directions by providing such a notch 109. The disc cartridge 101 is formed with recesses 110 to which a cartridge gripping mechanism of the cartridge exchange device is adapted for automatically performing loading and unloading operation of the recording apparatus to the cartridge loading portion by the cartridge exchange apparatus. One of the recesses 110 is formed on each side of the front portion of the main cartridge body 102 on which the shutter 107 is mounted. The recess 110 is formed so that they extend through the lower half 102b to a part of the upper half 102a and terminate at the upper end in the part of the upper half 102a. The cartridge holder 121 of the cartridge loading device for loading the thus formed disc cartridge 101 on the cartridge loading portion is formed as shown in Fig. 1. That is, the cartridge holder 121 comprises a main face 122 which is substantially the same size as that of the face of the optical-disc cartridge 101 and cartridge supports 123, 124 provided on the opposite sides of the main face 122. The cartridge supports 123 and 124 are bent in an L shape in section for holding the opposite sides of the main cartridge body 102. A cartridge holding portion 121a comprises an area surrounded by the main face 122 and the cartridge supporting portions 123 and 124. A shutter opening and closing lever 125 is mounted on the cartridge holder 121. The lever 125 is adapted to move the shutter 107 in a direction represented by an arrow A in Fig. 1 against a biasing force of a shutter closing spring 108 for opening each of the openings 104, 105 and 106 formed in the main cartridge body 102 when the disc cartridge 101 is inserted. The shutter opening and closing lever 125 has a shutter opening and closing pin 126 provided at the tip end thereof. The shutter opening and closing pin 126 projects downward from the lever 125 to the inside of the cartridge holder 121 through a rotary guide groove 127 bored in the main face 122 of the cartridge holder 121. The lever 125 is pivotally mounted on a pivot shaft 128 erected from the main face 122 of the cartridge holder 121 at the base end thereof so that the lever is rotatable around the pivot shaft 128. The shutter opening and closing lever 125 is biased by a tension spring 129 tentioned between the lever 125 and a misinsertion detecting lever which will be described hereafter so that it is biased in a direction B represented by an arrow B in Fig. 1. When the disc cartridge 101 is not inserted, the pin 126 of the shutter opening and closing lever 125 is engaged with a stopper piece formed at one end of a rotary guide groove 127 which will oppose to a shutter opening and closing pin engaging recess 111 formed in the disc cartridge 101 for restricting the rotary and biasing position of the lever. The shutter opening and closing pin engaging recess 111 is formed on one side of the shutter 107 which is in a close position and on the side opposite to one side of the main cartridge body 102 at which the notch 109 is formed. A misinsertion detecting lever 130 is mounted on the cartridge holder 121 in the vicinity of one 123 of the cartridge supports for detecting the misinsertion of the disc cartridge 101 to prevent the cartridge holder 121 from being inserted into the inside of the cartridge holder 121 when the disc cartridge 101 is inserted in a wrong direction. The misinsertion detection lever 130 has a misinsertion detection pin 131 projecting downward at the tip end thereof and is mounted on the main face 122 at the main base thereof so that it is pivotable around a pivot shaft 132 erecting on the main face 122 of the cartridge holder 121. The misinsertion detection pin 131 projects into the inside of the cartridge holder 121 through a notched hole 133 bored from the one cartridge support 123 to the main face 122. The misinsertion detection lever 130 is biased to rotate in a direction represented by an arrow C in Fig. 1 by a tension spring 129 tensioned between the lever 130 and the shutter opening and closing lever 125. When the disc cartridge 101 is not inserted, the rotating and biasing position of the misinsertion detecting pin 131 is restricted so that the misinsertion detection pin 131 may be engaged with a notch 109 of the disc cartridge 101 to be inserted into the cartridge holder 121. The restriction of the rotating an biasing position is achieved by the engagement of the misinsertion detection pin 131 with the edge of the side of the main face 122 in the notch 133. The disc cartridge 101 is inserted into the thus formed cartridge holder 121 through the insertion opening at the front side of the cartridge holder 121 while the upper side of the opening 104 for the magnetic head faces the main face 122 of the cartridge holder 121 the front side of the cartridge holder 121 on which the shutter 107 is mounted is a leading end for insertion and the opposite sides of the main cartridge body 102 are engaged with and supported by respective cartridge supports 123 and 124 as shown in Fig. 1. When the disc cartridge 101 is inserted into the cartridge holder 121 under a normal condition as shown in Fig. 1, the misinsertion detection pin 131 is brought into an engagement with the notch 109 of the disc cartridge 101. When the disc cartridge 101 is further inserted into the cartridge holder 121 from this position, the misinsertion detection lever 130 having the misinsertion detection pin 131 engaged with the notch 109 is rotated in a direction of an arrow C in Fig. 5 against the biasing force of the tension spring 129 while the misinsertion detection pin 131 is biased by the notch 109 so that the misinsertion detection pin will ride on one side of the main cartridge body 102 for enabling the disc cartridge 101 to be inserted to a proper loading position in the cartridge holder 121. When the disc cartridge 101 is further inserted into the inside of the cartridge holder 121 after the misinsertion detection lever 130 has been rotated as mentioned above, the shutter opening and closing pin 126 will be brought into an engagement with the shutter opening and closing pin engagement recess 111 of the disc cartridge 101. When the disc cartridge is further more inserted into the cartridge holder 121, the shutter opening and closing lever 125 is rotated in an opposite direction to the direction of arrow B in Fig. 1 against a biasing force of the tension spring 129 since the shutter opening and closing pin 126 is urged by the disc cartridge 101. The shutter 107 of the disc cartridge 101 is biased by the shutter opening and closing pin 126 against a biasing force of the shutter closing spring 108 to move in a direction of arrow A in Fig. 1 for opening each of the openings 104, 105 and 106. When the disc cartridge 101 has been inserted into a predetermined position in the cartridge holder 121, each of the openings 104, 105 and 106 is completely opened. If the disc cartridge 101 is misinserted from the rear side on which the shutter 107 is mounted, the misinsertion detection pin 131 would abut on and engaged with the rear side of the disc cartridge since the cartridge 101 is not formed on the rear side thereof with any notch which has been mentioned above. The misinsertion detection lever 130 is disabled to rotated for preventing the disc cartridge 101 from being inserted into the cartridge holder 121. That is, the misinsertion detection lever 130 prohibits the disc cartridge 101 from being inserted into the cartridge holder 121. A magneto-optical disc recording apparatus of the present invention has a disc cartridge 101 mounted thereto which houses an magneto-optical disc 103 as shown in Fig. 3 and is formed so that it is capable of recording information signals on the magneto-optical disc 103. The magneto-optical disc 103 has a signal recording layer in which so called "perpendicular magnetization" can be carried out. The magneto-optical disc 103 is formed so that magnetization direction of the signal recording layer is reversed for writing information signals thereon by heating the signal recording layer to a temperature not less than so called Curie temperature by irradiation with a laser beam and the like and by application of an external magnetic field on the heated area of the layer. A disc like chucking hub 3a formed of a metal and the like is firmly secured to the center of the magneto-optical disc 103. The magneto-optical disc recording apparatus of the present invention comprises a chassis 1 as shown in Fig. 7 and has a disc table 2 and an optical pick-up device 3 on the chassis 1. The disc table 2 formed in substantially disc shaped as shown in Fig. 8 and is mounted on a driving shaft 4a of a spindle mounter mounted on the chassis 1 so that the disc table 2 is supported in a parallel relationship with the chassis 1. The disc table 2 has a magnetic properties so that it attracts the chucking hub 101a provided in the center of the above mentioned magneto-optical disc 103. That is, the magneto-optical disc 103 is operated to rotate together with this disc table 2 when the spindle motor 4 is driver. The optical pick-up device 3 comprises a semiconductor laser 5 which is mounted on the chassis 1 as shown in Fig. 11 and serves as a light source. The optical pick-up device 3 is formed so that the laser beam emitted from the semiconductor laser 5 and incident upon and reflected by the magneto-optical disc 103 is detected by an optical detector 16 mounted on the chassis 1. That is, the laser beam emitted from the semiconductor laser 5 is transmitted through a collimator lens (not shown) and then through a beam splitter 6 and a galvanic mirror 7 which are mounted on the chassis 1 and is reflected by a reflection mirror (not sown) and is then incident upon an objective lens 8. The galvanic mirror is an optical device for achieving a so called tracking servo operation and is supported on a driving portion 7a and is operated to rock for deflecting the laser beam in such a direction that the beam will contact with and be separated from the chassis 1. The objective lens 8 is mounted on a lens bobbin 11 supported on a movable block 9 via a support arm 10. The movable block 9 is movably supported by a support rail 17 provided on the chassis 1. The thus supported objective lens 8 faces the signal recording surface of the magneto-optical disc 103 of the disc cartridge 101 which is loaded on the magneto-optical disc recording apparatus as will be described hereafter and is movable toward and away from the magneto-optical disc 103. The objective lens 8 is movable toward and away from the magneto-optical disc 103 by displacement of the support arm 10 for achieving so called focus servo operation. The objective lens 8 is moved by an objective lens driving mechanism (not shown) in such an axial direction that it is moved toward and away from the disc 103. The movable block 9 is moved along the support rail 17 in a radial direction of the disc 103 represented by an arrow X in Fig. 7 by a magnetic circuit comprising pairs of magnetic yokes 12, 12 and magnets 13, 13 which are provided on the chassis 1 and a pair of movable coils 14, 14 mounted on the movable block 9. The laser beam incident on the objective lens 8 is converged upon the magneto-optical disc 103 and is reflected by the magneto-optical disc 103 and is returned to the objective lens 8 again. The laser beam which has been returned to the objective lens 8 is passed through the reflection mirror and the galvanic mirror 7 and then transmitted through the beam splitter 6 and is incident upon an detector optical system provided on the chassis 1. The detector optical system 15 comprises a Wollaston Prism and a condenser lens and the like and is adapted to deflect the laser beam incident upon the detector optical system 15 depending upon the polarization direction for converging the beam upon the optical detector 16. A flying magnetic head 19 serving as an external magnetic field generator is mounted on the movable block 9 via the support arm 18 so that it is opposite to the objective lens 8. The support arm 18 is made of a thin metal sheet and the like so that it has a flexibility as shown in Fig. 13. The support arm 18 comprises a flexer portion 18a and a gimbal portion 18c which is formed on the tip of the arm 18 via a projection 18b formed integrally with the tip of the flexer portion 18a. The support arm 18 is supported on the movable block 9 by a support portion 18d provided at a base end which is mounted on the movable block 9 by setscrews. The flying magnetic head 19 comprises a core which is formed into a substantially square shape and a coil wound in the core for generating a magnetic field. When the disc main cartridge body 102 is loaded in the recording apparatus, the flying magnetic head 19 faces the objective lens 8 via the magneto-optical disc 103 and is biased to move to the magneto-optical disc 103 as shown by an arrow D in Fig. 1 by a spring force of the flexer 18a and the gimbal portion 18c as will be described hereafter. The core of the flying magnetic head 19 is held in such a condition that it is close to the magneto-optical disc 103 to form a very small space therebetween by the action of air entrained between the magneto-optical disc 103 and the flying magnetic head 19 when the magneto-optical disc 103 is rotated in such a condition. The disc recording apparatus comprises a disc cartridge loading mechanism formed on the chassis 1. The disc cartridge loading mechanism loads the disc cartridge 101 into a position where recording of information signal is formed by the disc recording apparatus. The disc cartridge loading mechanism comprises a cartridge holder 121 into which the disc cartridge 101 is inserted from the front side thereof and holds the inserted disc cartridge 101 and an eject plate 22 which is slidably supported on the chassis 1 for moving the cartridge holder 121 to and from the chassis 1. The eject plate 22 is provided with a pair of guide slits 22a, one for each side of the plate 22. Four positioning pins 23 erecting on the chassis 1 are inserted through the guide slits 22a so that the eject plate 22 is slidable on the chassis 1 in forward and rearward directions represented by arrows G and F in Fig. 13, respectively. Each of the positioning pins 23 is adapted to abut on the disc cartridge 101 for positioning the disc cartridge 101 when the disc cartridge 101 is loaded on the disc recording apparatus. The eject plate 22 is formed in the center thereof with a notch recess 31 which opens at the rear side of the plate so that the disc table 2 and the optical pick-up device 3 are exposed on the upper side thereof. Each pair of cam plates 25 and 26, 27 and 28 for moving the cartridge holder 121 to and from the chassis 1 is formed on the respective side of the eject plate 22 so that the plates erect from the plate. The cam plates 25 through 27 are provided with inclined cam faces 25a, 26a, 27a, 28a, respectively which are inclined toward the rear side. The eject plate 22 is biased in an forward direction represented by an arrow G in Fig. 1 by a pair of tension springs 30, 30 provided between a pair of projections 22b, 22b and a pair of engagement 29, 29 provided on the chassis 1. The eject plate 22 is bent on front side to form a manipulation button mount 31 on which an eject manipulation button can be mounted. The eject plate 22 is provided with a lock pin 32 on the upper face and the rear side thereof so that the pin is projected therefrom. When the eject plate 22 is in the eject position located at the rear side, the lock pin 32 is engaged with a lock lever 33 rotatably supported on the chassis 1 for locking the eject plate 22 in the eject position. The lock lever 33 is rotatably supported on a support shaft 34 erecting on the chassis 1. The lock lever 33 is biased to rotate in such a direction by a torsional coil spring 37 that an engagement portion 33a of the lever 33 which is formed into a hook shape at the tip thereof as shown by arrow H in Fig. 3. The torsional coil spring 37 is wound around the support shaft 34 and has one arm portion engaged with an engagement pin 35 erecting on the chassis 1 and the other arm engaged with a rotating pin 36 projected on the midportion of the lock lever 33. The rotating pin 36 is biased by the disc cartridge 101 which is inserted into the cartridge holder 121. The lock lever 33 is adapted to lock the eject plate 22 in the eject position and biases the disc cartridge 101 inserted into the cartridge holder 121 via the rotating pin 36 to a forward side as shown by an arrow G in Fig.3. A pair of opposing guide pieces 38, 38 are projected from the eject plate 22 on each side of the eject plate 22. The cartridge holder 121 is disposed on the eject plate 22. The cartridge holder 121 is formed into a flat plate which is substantially same as the disc cartridge 101. The chassis 1 are bent at opposite sides thereof to form a pair of slide guide walls 39, 39 having a L-shaped section, which are opposite with each other. Reception area 21a for receiving and holding the disc cartridge 101 are formed between the opposite slide guide walls 39, 39. The cartridge holder 121 is formed with inclined guide faces 40, 40 at the front end thereof so that the disc cartridge 101 is easily inserted to the holder 21 in an insertion direction represented by an arrow E in Fig. 3. When the disc cartridge 101 is inserted into the reception area 21a, the disc cartridge 101 is held in such a condition that the cartridge 101 faces the chassis 1 over an entire area thereof on the side of the chassis 1. A pair of guide pins 41 and 42, or 43 and 44 are projected from the respective outer side of the cartridge holder 121. The guide pins 41, 42, 43 and 44 are provided so that they correspond to the cam plates 25, 26, 27 and 28 of the eject plate 22, respectively. The cartridge holder 121 is disposed on the eject plate 22 while the rear side guide pins 42 and 44 are inserted between the guide piece 38 and 38 and the guide pins 41, 42, 43 and 44 rest on the inclined cam faces 25a, 26a, 27a and 28a, respectively. Accordingly, the cartridge holder 121 is moved toward and away from the chassis in directions represented by arrows I and J in Fig.3 when the eject plate is moved in forward and rearward directions represented by arrows G and F in Fig.3. A shutter opening and closing lever 45 which is formed into substantial L-shape is mounted on the upper surface of the cartridge holder 121 so that the lever 45 is rotatable along the upper surface of the cartridge holder 121. The shutter opening and closing lever 45 are rotatably supported on a support shaft 45a which is mounted on the cartridge holder 121 at the base end thereof. The lever 45 has a shutter opening pin 46 mounted on the tip end thereof. The pin 46 projects from the lever 45 through a slit 47 formed on the upper side of the cartridge holder 121 toward the chassis 1 and into the reception area 21a of the cartridge holder 121. The shutter opening and closing lever 45 is biased by a second tension spring 49 tensioned between a projection 45a provided on the shutter opening and closing lever 45 and a misinsertion detecting lever 48 mounted on the upper surface of the cartridge holder 121 for rotating in a direction represented by an arrow K in Fig. 3 so that the shutter opening pin 46 is moved toward the front end of the cartridge holder 121. The shutter opening and closing lever 45 is positioned by abutting at the tip end thereof on the stop piece 50 projecting on the cartridge holder 121 by a biasing force of the second tension spring 49. The shutter opening pin 46 of the thus positioned shutter opening and closing lever 45 is adapted into a shutter opening and closing pin engaging recess 111 of the disc cartridge 101 which is inserted into the reception 21a. The misinsertion detection lever 48 is formed by bending a metal plate in a substantially L-shape as shown in Figs. 4 and 9 and comprises a rotary arm 92 and a misinsertion detection piece 93 which is provided at one tip end thereof are is made normal to the rotary arm 92 by bending the metal plate said piece 93 serving as a misinsertion detection portion. The misinsertion detection piece 93 is formed with inclined bent pieces 93a and 93b on the opposite side thereof. The entire width (w₁) is made larger than the opening width (w₂) of the recess 110 formed on one side of the disc cartridge 101. The misinsertion detection lever 48 is pivotablly supported by a pivot shaft 95 which is inserted through a through hole 92a bored at the base end of the rotary arm 92 and is mounted on the cartridge holder 121 by being fitted into a hole 9 bored in the main face of the cartridge holder 121 as shown in Fig. 5. The lever 48 is thus rotatable around the shaft 95. At this time, the misinsertion detection piece 93 is located in the cartridge holder through a notch hole 96 bored from one of the slide guide walls 39 to the main face 91. The misinsertion detection lever 48 has a spring engagement piece 97 projecting on one side of the rotary arm 92 with which a second tension coil spring for biasing the shutter opening and closing lever 45 engaged at one end thereof so that the lever 48 is biased to move in a direction of an arrow C in Fig. 4. When the cartridge 101 is not inserted, the rotation position of the misinsertion detection lever 48 is restricted in such a manner that the misinsertion detection piece 93 is engaged with the notch 109 of the disc cartridge which is to be inserted into the cartridge holder 121. This restriction of the rotating and biasing position is achieved by the engagement of the misinsertion detection piece 93 with the edge of the main face 91 on the side of the notch 96. The disc cartridge 101 is inserted into the cartridge holder 121 including the thus formed misinsertion detection lever 48 through the insertion opening at the front side of the cartridge holder 121 while the upper side of the opening 104 for the magnetic head faces the main face 91 of the cartridge holder 121, the front side of the cartridge holder 121 on which the shutter 107 is mounted is a leading end for insertion and the opposite sides of the main cartridge body 102 are engaged with and supported by respective slide guide walls 39 and 39′. When the disc cartridge 101 is inserted into the cartridge holder 121 in such a manner, the misinsertion detection piece 93 is brought into an engagement with the notch 109 of the disc cartridge 101. When the disc cartridge 101 is further inserted into the cartridge holder 121 from this position, the misinsertion detection lever 48 having the misinsertion detection piece 93 engaged with the notch 109 is biased to rotate in a direction of an arrow C in Fig.4 against the biasing force of the second tension coil spring 49 while the misinsertion detection piece 93 is biased by the notch 109 so that the misinsertion detection piece 93 will ride on one side of the main cartridge body 102 for enabling the disc cartridge 101 to be inserted to a proper loading position in the cartridge holder 121. When the disc cartridge is further inserted into the inside of the cartridge holder 121 after the misinsertion detection lever 48 has been rotated as mentioned above, the shutter open and closing pin 46 will be brought into an engagement with the shutter opening and closing pin engagement recess 111 of the disc cartridge 101. The shutter opening and closing lever 45 is rotated in a direction of arrow L in Fig. 4 against a biasing force of the second tension coil spring 49 for releasing the shutter 107 of the disc cartridge 101. When the disc cartridge 101 has been inserted into a predetermined position in the cartridge holder 121, each of the openings 104, 105 and 106 of the cartridge 101 is completely opened. If the disc cartridge 101 is misinserted from the rear side thereof opposite to the front side on which the shutter 107 is mounted, the misinsertion detection pin 93 would abut on and engaged with the rear side of the disc cartridge 101 since the cartridge 101 is not formed on the rear side thereof with the notch 109 which has been mentioned above. The misinsertion detection lever 48 is disabled to rotate for prevention the disc cartridge from being inserted into the cartridge holder 121. That is, the misinsertion detection lever 130 prohibits the disc cartridge 101 from being inserted into the cartridge holder 121. The above mentioned cartridge holder 121 is formed with a notch recess 31 which opens rearward so that the flying magnetic head 19 and the support arm 19 for supporting the flying magnetic head 19 can face the disc cartridge 101 inserted into the reception area 21a. The magneto-optical disc recording apparatus comprises a lifter 52 which moves the flying magnetic head 19 to and from the magneto-optical disc 103. The lifter 52 is rotatably supported by a plunger supporting member 53 mounted on the rear side of the chassis 1. The lifter 52 has a base end supported by a support shaft 52a supported on the plunger supporting member 53 is a parallel relationship therewith and a tip end pointing toward the front side so that the tip end is positioned in the reception area 21a of the cartridge holder 121. That is, the lifter 52 is rotatable so that the tip end thereof can be moved to and from the chassis 1 in directions represented by arrows 0 and P in Fig. 3. The lifter 52 has on the base end side a plunger engaging piece 54 projecting toward the chassis 1 which is engaged with a driving shaft 55a of a plunger 55 supported by the plunger supporting member 53. That is, the lifter 52 is rotated to cause the tip end thereof to approach to the chassis 1 via the plunger engaging piece 54 in a direction represented by an arrow O in Fig. 3 when the plunger 55 is actuated so that the driving shaft 55a is moved rearward in a direction represented by an arrow Q in Fig. 3. The lifter 52 is formed with a spring engaging piece 56 and a position restriction piece 57 along the length thereof. The tip end of the spring engaging piece 56 is located on the side of the chassis 1 with beyond the cartridge holder 121. A third tension coil spring 58 is tensioned between the tip end of the piece 56 and an engaging piece 60 provided at the rear end of the cartridge holder. The position restriction piece 57 is positioned on one side of a position restriction click 59 facing the chassis 1. The click 59 projects from the cartridge holder 121 toward the inner side of the notch 21b. That is, the lifter 52 is biased by the third tension coil spring 58 to rotate so that the tip end thereof will leave from the chassis 1 in a direction represented by an arrow P in Fig.3 and is positioned in a position where the position restriction piece 57 abuts on the position restriction click 59. The lifter 52 is bent at the tip end to form a lift piece 61. The lift piece 61 is positioned on one side of the support arm 18 for supporting the flying magnetic head 19, facing the chassis 1. That is, the support arm 18 abuts on the lift piece 61 by the spring force of the flexer portion 18a and is supported by the lift piece 61. The magneto-optical disc recording apparatus is provided with a shipping lock lever 62. The shipping lock lever 62 is supported on the length thereof by a support shaft 62a to that it is rotatable relative to the eject plate 22. The shipping lock lever 62 has one end facing the front side of the movable block 9 of the optical pick-up device 3 and the other end facing the rear side of the positioning pin 23. The shipping lock lever 62 is biased by a fourth tension coil spring 65 tensioned between a spring engaging portion 63 provided at one end thereof and a spring engaging piece 64 provided at the rear end of the eject plate 22 so that one end of the lever 66 is moved toward the rear side of the apparatus in a direction represented by an arrow R in Fig. 3. The magneto-optical disc recording apparatus in provided with a power eject mechanism 66. The power eject mechanism 66 comprises an eject motor 67 disposed on the chassis 1, first to third reduction gears 68, 69, 70 for transmitting the driving force to the eject motor 67 and an eject gear 71. The eject gear 71 has an eject pin 72 in an eccentric position which erects from the gear 72. The eject pin 72 is positioned on the front side of an eject operation piece 73 provided at the end of the eject plate 22. When the eject motor 67 is driven, the driving force is transmitted to the eject gear 71 via reduction gears 68, 69 and 70 for rotating the gear 71 so that eject pin 72 biases the eject operation piece 73 rearward to move the eject plate 22 in a rearward direction represented by an arrow F in Fig. 3. The power eject mechanism 66 is formed in such a manner. In the thus formed disc recording apparatus, when the disc cartridge 101 is inserted from the front side into the reception area 21a of the cartridge holder 121, the shutter opening pin 46 is adapted into the shutter opening and closing pin engaging recess 111. The shutter lever 45 is rotated against the biasing force of the first coil spring 49 as shown by an arrow L in Fig. 7 so that the shutter 107 is moved in a direction represented by an arrow A in Fig. 3 to open each of the openings 104, 105 and 106 of the main cartridge body. At this time, the lifter 52 is rotated in a direction so that the tip end thereof is moved away from the chassis 1 in a direction of an arrow P in Fig. 9 depending on the position of the cartridge holder 121 since the position restriction click 57 abuts on the position restriction click 59. Accordingly, the support arm 18 is supported on the lift piece 61 and is held in a position where the arm 18 is displaced to move away from the chassis 1 against the spring force of the flexer portion 18a. Therefore, the disc cartridge 101 is inserted into a space between the flying magnetic head 19 and the movable block 9 without abutting on the flying magnetic head 19. At this time, the shipping lock lever 62 is biased to rotate so that one end thereof is moved in a rearward direction represented by an arrow Z in Fig. 12 by the fourth tension coil spring 65 as shown in Fig.12 and one end thereof abuts on the movable block 9 of the optical pick-up device 3. That is, the movable block 9 is held at a rear side position via the shipping lock lever 62 by the biasing force of the fourth tension coil spring 65. At this time, the support arm 18 is held together with the movable block 9 on a rear side position, that is, an outer peripheral position of the disc 103 by the shipping lock lever 62. Accordingly, the flying magnetic head 19 can be moved in such a direction that it is sufficiently separated from the chassis 1 without increasing the displacement of the flexer portion 18a. When the disc cartridge 101 is inserted into a position where the chucking hub 103a is opposite to the disc table 2, the cartridge 101 will urge the rotating pin 36 to rotate the lock lever 33 against the biasing force of the torsion coil spring 37 for releasing the engagement of the lock lever 33 with the lock pin 32. The eject plate 21 is then moved in a forward direction represented by an arrow G in Fig. 9 by the biasing force of the first tension coil spring 30. The cartridge holder 121 is moved so that the slide pins 41, 42, 43 and 44 move along the inclined cam faces 25a, 26a, 27a and 28a, respectively and the holder approaches the chassis 1 in a direction of an arrow J in Fig. 9 The disc cartridge 101 is then positioned and held by being sandwitched between the tip end of each positioning pin 23 and the cartridge holder 121. At this time, the chucking hub 103a rests on the disc table 2 so that is attracted to the disc table 2. Accordingly, the magneto-optical disc 103 is adapted to rotate by the rotation of the disc table 2. Since the support shaft 62a follows the eject plate 22 to be moved forward at this time as shown in Fig. 11, the shipping lock lever 62 abuts on the positioning pin 23 at the other end thereof and is rotated against the biasing force of the fourth tension coil spring 65 so that one end of the lever 62 is moved in a forward direction represented by an arrow W of Fig. 2, that is, away from the movable block 9. Accordingly, the movable block 9 is movable in a radial direction of the disc 103 along the support rail 17. Since the position restriction piece 57 abuts on the position restriction click 59, the lifter 52 is rotated to follow the cartridge holder 121 so that the tip end of the lifter 52 approaches to the chassis 1 in a direction of an arrow S in Fig. 9. Accordingly, the support arm 18 is displaced by a spring force of the flexer portion 18a in a direction of an arrow T in Fig. 9 so that the flying magnetic head 19 approaches the disc 103. Although the flying magnetic head 19 approaches to the magneto-optical disc 103, it is held in such a condition that it is not in contact with the disc 103. If the rotation of the disc 103 is commenced, the plunger 55 will be actuated as shown in Fig. 10 immediately after the commencement of the rotation of the disc 103 and the driving shaft 55a will be moved in a rearward direction represented by an arrow Q in Fig. 10. The lifter 52 is then rotated via the plunger engaging piece 54 in a direction of an arrow V in Fig. 10 against the biasing force of the third tension coil spring 58 so that the tip end thereof approaches to the chassis 1. Accordingly, the support arm 18 is returned by the spring force of the flexer portion 18a in such a direction of an arrow U in Fig. 10 that the flying magnetic head 19 abuts on the disc 103. When the flying magnetic head 19 approaches to the magneto-optical disc 103, the disc 103 has been already rotated. Accordingly, the above-mentioned air film has been formed to form a very narrow space between the disc 103 for holding the disc 103 in a close relationship with the head 19. Since the flying magnetic head 19 is mounted on the projection 18b at this time, the flexer portion 18a will not contact with the edge of the cartridge even if the flying magnetic head 19 approaches to the disc 103. In the disc recording apparatus, operation of the plunger 55 is released before the rotation of the disc 103 is stopped. The lifter 52 is then rotated by the biasing force the third tension coil spring 58 as shown in Fig. 9 so that the tip end thereof will moved away from the chassis 1 to a position where the position restriction piece 57 abuts on the position restriction click 59. Accordingly, the flying magnetic head 19 is moved away from the disc 103 while the disc 103 is being rotated. In order to eject the disc cartridge 101 from the disc recording apparatus, the manipulation button mount 31 is urged or the eject plate 22 is moved rearwardly by using the power eject mechanism 66. The cartridge holder 121 is then moved away from the chassis 1 while the guide pins 41, 42, 43 and 44 slide along the inclined cam faces 25a, 26a, 27a and 28a, respectively. At this time, the disc cartridge 101 is released from the holding by the tip end of each positioning pin 23 and the cartridge holder 121 and is moved in an eject direction represented by an arrow G in Fig.3 via the shutter opening and closing lever 45 and the lock lever 33 by the biasing force of the torsional coil spring 37 and the second coil spring 47. The movement of the disc cartridge 101 in such an eject direction causes the shutter opening and closing lever 45 to be rotated by the biasing force of the second tension coil spring 49 so that the shutter member 104 is moved to close each the openings 104, 105 and 106. At this time, the shipping lock lever 62 is rotated by the fourth tension coil spring 65 as shown in Fig. 12 so that one end thereof is moved in a rearward direction represented by an arrow z in Fig. 12. Accordingly, the movable block 9 of the optical pick-up device 3 is moved to a rear side position via the shipping lock lever 62 by the biasing force of the fourth tension coil spring 65 and is held in this position. Since the support arm 18 is held on the outer peripheral position of the disc 103 by the shipping lock lever 62, the support arm 18 enables the flying magnetic head 19 to move sufficiently away from the disc 103 without increasing the displacement of the flexer portion 18a. The lock lever 33 is rotated by the biasing force of the torsional coil spring 37 in association with the movement of the cartridge 2 in an eject direction so that the engagement 33a is brought into an engagement with the lock pin 32 for locking the eject plate 22 in an eject position. The support arm 18 which forms the disc recording apparatus is not limited to the above mentioned embodiment. Instead of being formed with the projection 18b at the tip end of the flexer portion 18a, as shown in Fig. 18a gimbal support member 74 forming a projection may be mounted on the tip end of the flexer 18a and further the gimbal portion 18c may be mounted on the tip end of the gimbal support member 74. In this case, the flying magnetic head 19 can move into the main cartridge body 102 to close access to the disc 103 without contact of the flexer portion 18a with the edge of the disc cartridge 101.

Claims: A magneto-optical recording apparatus for magneto-optical disc comprises: a cartridge holder (121) which is moveable toward and away from a chassis (1); a lifter (52) which is moveable to follow said cartridge holder (121); an external magnetic field generator (19) which is supported so that it is moveable toward and away from the chassis (1) and is supported in a position separated from a magneto-optical disc (103) of a disc cartridge (101) loaded on said cartridge holder by said lifter (52); and control means which is operative to move said external magnetic field generator (19) toward said magneto-optical disc (103) via said lifter (52) after commencement of the rotation of the magneto-optical disc (103) and to move said external magnetic field generator (19) away from said magneto-optical disc (103) via said lifter (52) before stopping of the rotation of the magneto-optical disc (103), wherein said external magnetic field generator (19) is supported by a rotatable arm (18) so that said generator (19) is moveable by said lifter (52) toward and away from a magneto-optical disc (103) and is moveable together with said arm (18) in a radial plane which is perpendicular to said magneto-optical disc (103). A magneto-optical recording apparatus according to claim 1, wherein said external magnetic field generator (19) is moveable in an outer radial direction of said magneto-optical disc (103) when magneto-optical disc (103) is unloaded. A magneto-optical recording apparatus according to claim 1 or 2, wherein said external magnetic field generator (19) is mounted on a projection (18b, 74) provided on one side of a rotatable arm (18) facing the magneto-optical disc. A magneto-optical disc recording apparatus according to claim 1 or 2, wherein said external magnetic field generator (19) is provided integrally with the optical head device (3) of said recording portion. A magneto-optical disc recording apparatus according to claim 4, wherein said external magnetic field generator comprises an arm-like member (18), and a magnetic head device (19) provided on a projection (18b, 74) on the side of the arm-like member (18) facing the magneto-optical disc (103). A magneto-optical recording apparatus according to any one of the preceding claims, wherein said recording apparatus further comprises misinsertion detection means (48), said misinsertion detection means including a misinsertion detection portion (93) which is urged to move in an outer direction of the cartridge holding portion of said cartridge holder (121) by the disc cartridge (101) when the disc cartridge (101) is inserted into said cartridge holder (121) and is engaged with said disc cartridge (101) when said disc cartridge (101) is misinserted for preventing said disc cartridge (101) from being inserted into said cartridge holder (121) said misinsertion detection portion (93) of said misinsertion detection means (48) having a width (w₁) larger than the opening width (w₂) of a recess (110) on the side of the disc cartridge (101) on which the notch (109) is formed.

Inventors: INOUE HIDEKI C O SONY CORPORAT, INOUE, HIDEKI, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1991
Main classification: G11B17
IPC codes: G11B19, G11B17, G11B11