Disk recording and/or reproducing apparatuses have hitherto been provided to record and/or reproduce information signals from disk-like recording mediums generally called optical disks such as a CD (compact disc) or a CD-Rom (CD-read-only memory) or a magneto-optical disk (OD: optical magnetic disk).
This disk recording and/or reproducing apparatus comprises a disk rotation mechanism for rotating a turntable to spin a disk-like recording medium thereon, an optical pickup device for writing and reading an information signal on and from the disk-like recording medium that is being rotated by this disk rotation mechanism, a disk transport mechanism for transporting the disk-like recording medium between a disk loading unit with the turntable within a main chassis that houses the disk rotation mechanism and the disk entrance and exit slot and the like.
As the disk recording and/or reproducing apparatus having such arrangement, there is known such a disk recording and/or reproducing apparatus as described in Japanese laid-open patent application No. 10-340513, for example. FIG. 53 of the present application shows a schematic arrangement of such disk recording and/or reproducing apparatus. In FIG. 53, reference numeral 1 generally denotes a disk recording and reproducing apparatus. This disk recording and reproducing apparatus 1 has a housing 2 with a front surface in which there is formed an oblong slit-like disk entrance and exit slot 2a. Information is recorded on and reproduced from an optical disk D, which is a disk-like recording medium inserted into and ejected from this disk entrance and exit slot 2a, by the disk recording and reproducing apparatus 1.
In order to insert and eject the optical disk D into and from this disk recording and reproducing apparatus 1, a disk transport mechanism 4 is provided at the inside of the disk entrance and exit slot 2a of the housing 2. The disk transport mechanism is composed of a transport roller 5 for applying force to the optical disk D so that the optical disk may be inserted into and ejected from the disk recording and reproducing apparatus, a guide member 6 provided above the transport roller 5 in an opposing relation and the like. The transport roller 5 is formed as a hand drum-like roller member with a narrow central portion made of a material such as synthetic rubber having a relatively large friction coefficient. The guide member 6 serves to guide the optical disk D to a turntable and is made of a material such as synthetic resin having a small friction coefficient.
The guide member 6 has an arc-like groove portion 6a formed on its surface opposing the transport roller 5 to face the outer peripheral surface of the transport roller 5. Further, the surface on which thee guide member 6 has the groove portion 6a is formed as an arc-like guide surface 6b in which an intermediate portion is recessed in the longitudinal direction. Then, the transport roller 5 is constantly biased to the side of the guide member 6 by spring force of a spring, not shown. The optical disk D is inserted into the space between the transport roller 5 and the guide member 6. The optical disk D held by the transport roller and the guide member from the upper and lower directions is transported to the disk loading portion provided within the housing 2 or to the disk entrance and exit slot 2a provided outside the housing 2 in response to its rotational direction as the transport roller 5 rotates.
In this case, when the optical disk D is inserted into the disk recording and reproducing apparatus from the disk entrance and exit slot 2a of the housing 2, the transport roller 5 is rotated by a motor, not shown, to sandwich the optical disk D between it and the guide member. At that time, a gap formed between the transport roller 5 and the guide member 6 is barrel-like space whose width increases in its central portion and whose width decreases at the respective ends thereof. Therefore, outer peripheral edges of the upper and lower surfaces of the optical disk D are constantly brought in contact with the transport roller 5 and the guide member 6, and the optical disk D is transported by friction force generated in this contact portions. Then, when the center hole d of the optical disk D corresponds to the central portion of the turntable, a chucking arm, not shown, is lowered to make a chucking member overlap each other. At that time, the transport roller 5 is detached from the guide member 6 and lowered.
On the other hand, when a user selects the eject operation of the optical disk D by operating an eject button or the like, the transport roller 5 is elevated and spring-biased toward the guide member 6 by spring force of the spring. As a result, the optical disk D is sandwiched by the transport roller 5 and the guide member 6 from the upper and lower directions, and the optical disk D is released from being clamped to the turntable. Consequently, by rotation force of the transport roller 5, the optical disk D is transported to the side of the disk entrance and exit slot 2a and is placed in the state in which it can be ejected from the disk recording and reproducing apparatus.
However, in the disk recording and reproducing apparatus according to the prior art, since the hand drum-like transport roller 5 with the narrow central portion is made of the material such as the synthetic rubber having the relatively large friction coefficient and this transport roller 5 is urged against the guide member 6 by spring force, the surface of the transport roller 5 undergoes elastic deformation to thereby change into a cylindrical flat surface. This flat surface is brought into pressed contact with a signal recording surface of the optical disk D.
For this reason, when the optical disk D is inserted into the disk recording and reproducing apparatus under the condition that the signal recording surface is being attached with minute foreign objects (dusts, etc.), the foreign objects are pressed against and dragged along the signal recording surface by the transport roller 5 so that the signal recording surface is damaged. In consequence, when the signal recording surface is damaged, not only the signal recording surface looks like a considerably damaged signal surface but also a signal that was recorded before hand cannot be read out from the optical disk and a new information signal cannot be written on the optical disk.
In conventional disk recording and reproducing apparatuses, since the disk entrance and exit slot 2a into and from which the optical disk D is inserted and ejected is maintained while in the state of being opened, dusts tend to easily enter into the housing 2.
Further, since a disk transport mechanism 4 includes the transport roller 5 and the guide member 6 to sandwich the optical disk D and the optical disk D is transported to the disk surface direction by rotation force of the transport roller 5, the optical disk D can be held and transported by sufficiently large force. However, during the period in which the optical disk is passing the intermediate portion of the transport process, holding of the optical disk D becomes unstable. Thus, when the optical disk D is ejected from the disk entrance and exit slot, the optical disk D is disengaged from the disk transport mechanism 4 and the optical disk D will drop from the disk entrance and exit slot under its own weight.
In view of the problems encountered by the prior art, when the disk-like recording medium is inserted into and ejected from the disk recording and/or reproducing apparatus, a disk transport mechanism can be prevented from contacting with a signal recording surface of a disk-like recording medium so that the signal recording surface can be protected from being damaged and the disk transport mechanism side can contact with only the outer peripheral edge of a disk-like recording medium and can transport the disk-like recording medium. Further, it is an object of the present invention to provide a disk recording and/or reproducing apparatus in which resistance force generated when a disk-like recording medium is inserted into and ejected from the apparatus can be changed. Accordingly, when the disk-like recording medium is inserted into the apparatus, the disk-like recording medium can easily be inserted into the disk recording and/or reproducing apparatus. On the other hand, when the disk-like recording medium is ejected from the disk recording and/or reproducing apparatus, the disk-like recording medium that was ejected somewhere in the disk entrance and exit slot can be held.