JP3383443B2 - Disc reproducing apparatus and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a CD player, a CD-
The present invention relates to a disc reproducing device for reproducing information recorded on an optical disc such as a ROM drive and a control method thereof.

[0002]

2. Description of the Related Art In recent years, disk drives such as CD-ROM drives, which use optical disks as recording media, have become smaller and lighter, and along with this, the development of disk drives built in portable computers has been actively pursued. Has been done in. The mainstream of such a disc drive is configured so that the tray on which the disc is mounted can be inserted and removed horizontally with respect to the cabinet, that is, along the direction of the surface of the disc mounted on the tray.

By the way, up to now, a pickup of a disk drive has been mounted with an electronic component such as a laser diode, which has a high possibility of causing electrostatic breakdown or deterioration of performance, but is externally (for example, a disk motor). It is general that no safety measures such as this have been taken against the electrostatic discharge of, for example, 8 kV. Therefore, the pickup is constantly in danger of causing breakdown such as electrostatic breakdown and performance deterioration of the laser diode, and has great concern about reliability.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem, and can cause electrostatic breakdown or performance deterioration such as a laser diode mounted in a pickup due to external high voltage discharge. It is an object of the present invention to provide a disc reproducing apparatus and a control method therefor capable of stably protecting an electronic component having high property.

[0005]

In order to achieve the above object, the disc reproducing apparatus of the present invention has a disc mounted therein.
A disc that allows the tray to be put in and taken out of the cabinet
Read the information recorded on the disc with the playback device.
The pickup for picking up and this pickup
A feed motor for feeding the disc in the radial direction, and
Rays are exposed from inside the cabinet
And a tray for detecting the tray by the detector.
Is exposed from inside the cabinet
When you do, send the pickup to the designated standby position.
Control means for controlling the feed motor, and
Therefore, when the pickup is sent to the standby position
The elastically contact with the pickup,
And an elastic conductive member for grounding the ground .

[0006]

Further, in order to achieve the above object, the present invention provides
In a disc reproducing apparatus in which a tray for mounting a disc can be freely taken in and out of a cabinet, a pickup for reading information recorded on the disc and a pickup for sending the pickup in a radial direction of the disc
Remove the feed motor and the tray from the cabinet.
Detection to detect the occurrence of a tray ejection order to issue
The output means and the detection means issue the tray discharge command.
When the raw is detected, the pickup is placed in a predetermined standby position.
Control means for controlling the feed motor to feed the
This control means causes the pickup to move to the standby position.
When it is sent to
An elastic conductive member for grounding the pickup is provided.

[0008]

[0009]

In other words, in the present invention, the tray is a cabinet.
When it is exposed from inside the net,
-When the eject command is issued, move the pickup to the standby position.
Connect the pickup to earth by controlling it to move.
By doing so, the electric charge accumulated in the pickup due to the high voltage discharge from the outside can be released to the outside through the elastic conductive member, and the danger that the laser diode etc. will be electrostatically destroyed can be eliminated. .

[0010]

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are perspective views showing the external appearance of a portable computer-mounted CD-ROM drive according to an embodiment of the present invention.

As shown in FIG. 1, this CD-ROM drive is installed by being inserted into a slot provided in a personal computer. Personal computer
It is a thin type of so-called laptop, notebook or book type, and as shown in the figure, the CD of this embodiment.
The ROM drive is installed by being inserted into, for example, a slot provided under the keyboard of a personal computer.

In a CD-ROM drive, a tray 2 for mounting a CD-ROM disc (not shown) is horizontally placed on a metal cabinet (reference numeral 1 in the drawing) (the surface of the disc mounted on the tray 2). It has a structure that allows it to be taken in and out freely (along the direction). The cabinet 1 has an opening 3 on one surface for loading and unloading the tray 2, and the opening 3
A decorative frame 4 is fitted around the.

FIG. 2 is a view showing a state where the tray 2 is discharged from the cabinet 1. As shown in this figure, the tray 2 is formed with a disc mounting recess 6 for mounting the disc in a fixed position, and notches 7 are provided at opposing positions on both sides of the tray 2 so that the disc can be easily taken out from the recess 6.
Is provided. A turntable 8 directly connected to a disc motor (not shown) is arranged in the center of the recess 6, and the center of the turntable 8 is fitted with a center hole of the disc to turn the disc into a turntable. A disc chuck 9 for mounting and fixing in a fixed position on 8 is projected. Further, in the concave portion 6, the pickup lens 1 of the optical pickup arranged on the back side of the tray 2 in the figure.
A window 11 is opened to expose 0 to the mounted disk surface.

Reference numeral 13 is a front panel attached to the tray 2, and the front panel 13 is provided with an eject button 14 which is pressed when the tray 2 is ejected from the cabinet 1. Further, reference numeral 15 is an opening opened in the cabinet 1, and this opening 15 is opened at a position substantially overlapping the disc chuck 9 when the tray 2 is accommodated in the cabinet 1, as shown in FIG. Between the inner surface of the cabinet 1 and the disc chuck 9, a tray 2 is provided to reduce the overall thickness of the drive device.
There is only a small gap so that they do not come into contact with each other during insertion / ejection. Therefore, the opening 15 functions as a relief against interference between the disc chuck 9 and the cabinet 1 when, for example, vibration is applied from the outside. Further, the opening 13 contributes to the heat radiation effect in the cabinet 1.

FIG. 3 is an exploded view of the structure of the CD-ROM drive of this embodiment.

As shown in the figure, the cabinet 1 is covered on one surface with an upper lid 1A. In the cabinet 1, semiconductor elements such as a microcomputer and various motor drive circuits, and a printed wiring board 22 on which various electronic components such as a connector 21 for electrical connection with an external device (host computer) are mounted, A tray lock mechanism 30 and the like for locking the tray 2 housed in the cabinet 1 at a fixed position where the disc reproducing operation is possible is built in.

Further, 40 and 41 are sliders attached to both side portions of the tray 2, respectively. These sliders 40 and 41 move in the moving direction of the tray 2 (arrow Y-
Mounted so as to be slidable in the Y'direction), and its tip extends from a position substantially flush with the insertion-side tip surface of the tray 2 to a position protruding from the insertion-side tip surface as shown in the drawing. Has become. The sliders 40 and 41 are respectively configured to engage with the slider rails 50 and 51 provided in the cabinet 1 so as to be supported and guided by the slider rails 50 and 51, respectively. FIG. 7 shows the positions of the sliders 40 and 41 when the tray is ejected. As shown in the figure, each slider 4
0 and 41 are pulled out to the inside of the cabinet 1 to the full extent, and almost half of the entire length is supported by the slider rails 50 and 51. Each of the slider rails 50 and 51 has a U-shaped cross section so that the sliders 40 and 41 can be held even in the vertical direction, so that the tray 2 discharged from the cabinet 1 is supported in a cantilevered state. Work as intended.

Further, the tray 2 is provided with two long grooves 16, 16 in parallel along the moving direction of the tray 2. These long grooves 16 and 16 stop slightly before the insertion-side tip of the tray 2. These long grooves 16, 16
The stopper pins 17, 17 projecting from the inner surface of the upper lid 1A of the cabinet 1 are inserted into this. Then, the stopper pins 17, 17 are guided by the long grooves 16, 16 as the tray 2 is taken in and out of the cabinet 1, and the stopper pins 17, 17 are guided when the tray 2 is completely discharged.
Is restricted at the ends of the long grooves 16, 16.

Further, in FIG. 3 and FIG. 4, a portion indicated by 60 is a printed wiring board 2 in the cabinet 1.
2 and a printed wiring board (not shown) in the tray 2 are supported by the flexible wiring board 61, and when the tray 2 is housed in the cabinet 1, the flexible wiring board 61 is placed in the tray 2 It is a guide member for guiding so as to be accommodated in a predetermined accommodation space (a portion indicated by 77 in FIG. 12) therein.

FIG. 5 is a sectional view showing the details of the disk drive mechanism provided in the tray 2 and a plan view thereof.

As shown in the figure, the disk drive mechanism is
It is composed of a disk motor 53 and a turntable 8 fixed to the motor shaft of the disk motor 53. At the center of the turntable 8, a disc chuck 9 for positioning the disc D on the turntable 8 and detachably fixing the disc D is integrally and projectingly provided. On the outer peripheral portion of the disc chuck 9, three chuck chips 9a are embedded along the peripheral surface of the disc chuck 9 at equal intervals so as to partially project from the peripheral surface of the disc chuck 9. Each chuck tip 9
A is pressed in the radial direction from the center of the disk chuck 9 by a compression spring 9b in the disk chuck 9, and is supported so as to be able to move back and forth within a predetermined stroke length along the radial direction. That is, each chuck tip 9a is pushed back by the wall surface of the center hole of the disk when the disk D is mounted, and once retracts, and thereafter, as the disk D is dropped on the turntable 8, it moves forward by the force of the compression spring 9b. As a result, the disk D is elastically pressed by the lower spherical surface of each chuck tip 9a and is stably set on the turntable 8.

In the present embodiment, each chuck tip 9a
In order to retract the tip 9a into the chuck 9 by pressing from the wall surface of the center hole of the disc D when the disc D is mounted, the flat surface A having its upper end parallel to the disc surface is formed. The acting portion is constituted by a flat surface (tapered surface) B inclined with respect to the disk surface. The portion that acts to press the disc D from above and stably mount it on the turntable 8 is formed as a spherical surface C as before.

Therefore, if the height of the disc chuck 9 is determined so that the upper end surface of the disc chuck 9 is evenly aligned with the flat surface A of the upper end of each chuck tip 9a, the height of the disc chuck 9 is determined as shown in FIG.
As shown in FIG. 2, the height dimension of the disc chuck 9 can be reduced by h as compared with the conventional one using a metal ball (shown by the one-dot chain line in the figure), which contributes to the thinning of the entire disc drive. be able to.

Next, the details of the tray lock mechanism and the operation at the time of inserting / ejecting the tray 2 will be described with reference to FIGS.

FIG. 7 is a view showing a state when the tray is discharged. At this time, the stopper pins 17, 17 projecting from the inner surface of the upper lid (not shown) of the cabinet 1 are attached to the tray 2
Are located at the ends of the long grooves 16, 16 provided in the, and this defines the position of the tray 2 at the time of ejection. Thus, in this embodiment, the stopper pins 17, 1
7 and the long grooves 16 and 16 realize a positioning mechanism for discharging the tray with a simple structure, and the device can be made small and thin.

When the tray 2 is pushed into the cabinet, as shown in FIG. 8, the flexible wiring board 61 is inserted into the accommodation space 77 of the flexible wiring board provided under the tray 2 together with the guide member 60. When the tray 2 is finally housed in the cabinet 1, it is housed in the housing space 77 as shown in FIG. As shown in FIG. 12, in this embodiment, the accommodation space 7 for the flexible wiring board 61 is provided.
7 is provided in an elongated shape along the moving direction of the tray 2. Therefore, it is not necessary to increase the depth of the tray 2, and the size and thickness of the entire disc drive can be reduced.

Further, when the tray 2 is inserted further deeply from the state shown in FIG. 8, the rear end surface 2A of the tray 2 comes into contact with the tray ejection lever 78 provided in the cabinet 1. The tray discharge lever 78 is slidably supported within a certain distance along the moving direction of the tray 2,
The force of the spring 79 urges the arrow Y'direction, that is, the tray discharge direction. Therefore, the rear end surface 2 of the tray 2
At A, move the tray eject lever 78 to the tray insertion direction (Y direction).
The spring 79 gradually expands by pushing to, and its repulsive force increases.

Further, when the tray 2 is inserted to the state shown in FIG. 9, the lock pin 68 provided so as to vertically project from the lower surface of the tray 2 comes into contact with the tapered surface 69a of the lock lever 69 provided in the cabinet 1. Contact. Here, the lock lever 69 has two guide shafts 57, 57 projecting from the cabinet 1 inserted into the two parallel guide grooves 55, 55 so that the movement range thereof is restricted, that is, the lock lever 69. Is supported so that it can move back and forth in the direction of arrow XX '. In addition, the lock lever 69 is the spring 5
It is pulled in the direction of the arrow X by the force of 9.

When the lock pin 68 comes into contact with the tapered surface 69a of the lock lever 69 by inserting the tray 2, the tray 2 is inserted further deeply and the lock lever 69 is spring 59 in the direction of the arrow X '. Move in parallel against the force of. Then, when the lock pin 68 gets over the end of the tapered surface 69a, the lock lever 69 slides in the direction of the arrow X by the spring force, and as shown in FIG.
The lock pin 68 is inserted into the hook portion (lock portion) 69b. As a result, the tray 2 is locked at a fixed position in the cabinet 1 by the lock mechanism 30.

When ejecting the tray 2 from the cabinet 1, as shown in FIG. 11, the eject button 14 is pressed to unlock the tray 2. In the tray stored state, the eject button 14 is in contact with the tip of one of the sliders 41, and by pushing the eject button 14, the slider 41 is slid in the tray insertion direction (arrow Y direction). The tip of the slider 41 is in contact with the second tapered surface 69c of the lock lever 69, and the slide movement of the slider 41 in the tray insertion direction causes the lock lever 69 to oppose the force of the spring 59 in the arrow X'direction. Moving. This allows the tray 2
Of the lock pin 68 is the hook portion 69b of the lock lever 69.
Then, the tray 2 is pushed slightly forward (in the direction of the arrow Y ') by the tray discharge lever 78 biased by the spring 79. This state (almost as shown in FIG. 9)
Then, the user can pull out the tray 2 by putting his / her finger on the front panel 13 of the tray 2, and then the user can pull out the tray 2 to the full extent.

Next, the internal structure of the tray 2 will be described.

FIG. 12 is a view showing the inside of the tray with a metal cover (not shown) covering the back side surface of the tray 2 removed.

In the figure, 18 is an optical pickup, and this pickup 18 has two guide shafts 71,
It is erected slidably between 72. One guide shaft (hereinafter, referred to as a lead screw) 72 of the two guide shafts 71 and 72 has a screw-like groove formed on the peripheral surface thereof over substantially the entire length. The lead screw 72 is rotatably supported by the tray base 2. A gear 73 is attached to one end of the lead screw 72. Reference numeral 74 is a pickup feed motor, and the power of the motor 74 is transmitted to the gear 73 through various transmission gears, whereby the lead screw 72 is rotationally driven. The pickup 18 is connected to the lead screw 72 via a power transmission means 80, which will be described later, and is configured to be fed and driven by the rotation of the lead screw 72.

In FIG. 12, 75 is a motor support base for supporting the disc motor 53, and 76 is a standby position near the disc motor of the pickup 18 or a region on the disc where the disc management information is recorded, TO.
A ground spring for contacting the pickup 18 and grounding the pickup 18 when the C (Table of Contents) area is in a position where it can be read. further,
Reference numeral 77 denotes an accommodation space for the flexible wiring board 61 when the tray 2 is accommodated in the cabinet 1. As described above, in this embodiment, the accommodation space 77 for the flexible wiring board 61 is provided in an elongated shape along the moving direction of the tray 2.

FIG. 13 is a plan view showing the details of the pickup feed mechanism, and FIG. 14 is an exploded view showing the structure of the connecting portion (power transmission means 80) between the lead screw and the pickup in this pickup feed mechanism.

As shown in these figures, the pickup 1
Reference numeral 8 denotes a first leaf spring member 82 and a second leaf spring member 82 to which a rack member 81 having a groove that meshes with the groove of the lead screw 72 is fixed.
It is connected to the lead screw 72 via a power transmission means 80 composed of a leaf spring member 83. The first plate spring member 82 presses the rack member 81 fixed to the first plate spring member 82 into the groove of the lead screw 72 with an appropriate pressure (minimum necessary pressure capable of sending the pickup 18), whereby Groove and rack member 81
It works by pressing and bonding.

By the way, in this disc drive, the pickup 1 moves when the pickup 18 moves to a position where the TOC area on the disc can be read.
A switch 91 is provided for detecting by pressing from 8 itself. The switch 91 is constantly urged by a spring force (not shown) in a direction against the pressure from the pickup 18. Therefore, the pickup 18
When the switch presses the switch 91, the pickup 18
Since the load for sending the spring increases by the repulsive force of the spring,
As shown in FIG. 15, the first leaf spring member 82 does not withstand this load and bends outward, so that the lead screw 72
The engagement between the groove and the rack member 81 is about to come off. But,
At this time, the second plate spring member 82 is placed outside the second plate spring member 82.
Due to the repulsive force of the plate spring member 83, the rack member 81 maintains the meshed state without being disengaged from the groove of the lead screw 72. That is, the second leaf spring member 83 is not in contact with the first leaf spring member 82 during normal traveling of the pickup 18, or the pressing force from the second leaf spring member 83 is applied to the first leaf spring member 82. The first leaf spring member 82 exerts its elastic force only when the first plate spring member 82 is bent outward so that the pressing force of the rack member 81 against the groove of the lead screw 72 is increased. The rack member 81 acts so as not to come off from the groove of the lead screw 72.

With this structure, as the pressing force of the first leaf spring member 81, even if the pickup 18 comes to a position where the TOC area on the disk can be read and receives the reaction force from the switch spring, The minimum force required for sending the pickup 18 is sufficient, and the load on the motor 74 for sending the pickup 18 is also required minimum.

Further, in the present embodiment, when the pickup 18 is at its standby position or at a position where the TOC area on the disk can be read, as shown in FIG.
Is configured to elastically contact with. FIG. 16 is a side sectional view of the tray 2. As shown in this figure, the earth spring 76 is a metal plate 92 attached to the tray base 2.
Is stuck to. The metal plate 92 is a metal cover 7 that covers the back side of the tray 2 through a set earth spring 93.
It is electrically coupled to 0. Further, the metal cover 70 is electrically coupled to the metal cabinet 1 via a conductive member (not shown).

Therefore, with this configuration, the pickup 18 is grounded each time it moves to the standby position, and the electric charge accumulated by the high voltage discharge from the outside can be released to the outside, and the laser diode or the like can be released. The risk of electrostatic breakdown can be eliminated.

Next, in this disc drive, the structure and operation for moving the pickup 18 to its standby position and grounding it will be described with reference to FIGS. 17 and 18.
Will be explained.

In FIG. 17, 171 is a pickup 1
8 is a ground line (including a ground spring 76) for contacting with 8 to ground the ground, 172 is a pickup feeding means, 173 is a pickup position detecting section for detecting the position of the pickup 18, and 174 is a control section. Control unit 17
A pickup position 4 receives a pickup position detection signal from the pickup position detector 173 and determines whether or not the pickup 18 is at the standby position. A tray open detector 175 detects whether the tray 2 is in an open state, that is, whether it is exposed from the cabinet 1. here,
The state in which the tray 2 is exposed from the cabinet 1 means a state in which the tray 2 is protruding from the cabinet 1 as much as possible in the disc drive of the present embodiment. In short, the tray is slightly separated from the disc reproducible position. Refers to when in position. An initialization detection unit 176 detects initialization of the disk drive, and detects initialization by detecting power-on, STOP key input, tray insertion state, and the like. Reference numeral 177 is an instruction input unit for inputting an instruction to open the tray 2. The outputs of the pickup position detection unit 173, the tray open detection unit 175, the initialization detection unit 176, and the command input unit 177 are input to the control unit 174, and the control unit 174 picks up as follows based on the input from each of the above units. Control for moving 18 to the standby position is performed. That is, as shown in FIG. 18, the control unit 174 first determines whether or not the pickup 18 is at the standby position based on the pickup position detection signal of the pickup position detection unit 173 (step 181). When the pickup 18 is not in the standby position, the control unit 174 sequentially checks the presence / absence of a tray open command from the command input unit 177, the tray open detection result of the tray open detection unit 175, and the initialization detection result of the initialization detection unit 176 ( (Steps 182, 183, 184), when it is determined that there is a tray open command in step 182, or step 18
If the tray open state is detected in 3 or the initialization state is detected in step 184, the pickup 1
The pickup feeding means 172 is controlled so as to move 8 to the standby position and electrically connect to the earth line 171 (step 185).

As a result, at least while the tray 2 is exposed from the cabinet 1, the pickup 18 can be reliably brought into contact with the earth line (earth spring 76) to ground the pickup 18.

The movement control of the pickup to the standby position may be performed by software in the host computer.

[0047]

As described above, according to the present invention ,
The ray is exposed from inside the cabinet
Or when a tray ejection command is issued, pick up
Control to move the pickup to the standby position.
By connecting the battery to the ground, the charge accumulated in the pickup due to high voltage discharge from the outside can be released to the outside through the elastic conductive member, eliminating the risk of electrostatic damage to the laser diode etc. can do.

[Brief description of drawings]

FIG. 1 is a perspective view showing an external appearance of a CD-ROM drive according to an embodiment of the present invention when a tray is inserted.

FIG. 2 is a perspective view showing an appearance of the CD-ROM drive of FIG. 1 when a tray is ejected.

FIG. 3 is a perspective view showing an exploded configuration of the CD-ROM drive of FIG.

FIG. 4 is a perspective view showing a flexible wiring board connected between a tray and a cabinet.

5A and 5B are a cross-sectional view and a plan view showing details of a disk drive mechanism built in a tray.

6 is a sectional view showing details of a disc chuck in the disc drive mechanism of FIG. 5 in comparison with a conventional example.

7 is a plan view showing a state of the CD-ROM drive shown in FIG. 1 when a tray is ejected.

FIG. 8 is a plan view showing a state in which the tray is inserted halfway from the state of FIG.

9 is a plan view showing a state when the tray is inserted further deeply from the state of FIG.

FIG. 10 is a plan view showing a state where tray insertion is completed (tray storage state).

FIG. 11 is a plan view for explaining the operation when the tray is discharged.

FIG. 12 is a perspective view showing the internal structure of the tray.

FIG. 13 is a plan view showing details of a pickup feeding mechanism.

14 is an exploded view showing a configuration of a connecting portion between a lead screw and a pickup in the pickup feeding mechanism of FIG.

FIG. 15 is a plan view for explaining the operation of the connecting portion between the lead screw and the pickup shown in FIG.

FIG. 16 is a tray side sectional view for explaining an earth spring in the tray.

FIG. 17 is a block diagram showing a configuration of a part that controls movement of a pickup to a standby position.

18 is a flowchart for explaining the operation of FIG.

[Explanation of symbols]

1 ... Cabinet, 2 ... Tray, 18 ... Pickup,
76 ... Earth spring.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 7/085 G11B 7/12 G11B 21/02 G11B 25/04

Claims (4)

(57) [Claims] 1. A tray for mounting a disc
A disc playback device that can be put in and taken out in the vignette
Te, a pickup for reading information recorded on the disk, a feed motor for feeding the pickup in a radial direction of the disk, detection for detecting that the tray is exposed from within the cabinet Means and control means for controlling the feed motor to feed the pickup to a predetermined standby position when the detection means detects that the tray is exposed from the inside of the cabinet; A disk reproducing device, comprising: an elastic conductive member that elastically contacts the pickup to ground the pickup when the pickup is sent to the standby position. 2. A tray for mounting a disc
A disc playback device that can be put in and taken out in the vignette
Te, bets for discharging a pickup for reading information recorded on the disk, a feed motor for feeding the pickup in a radial direction of the disk, the tray from within the cabinet
Detection means for detecting the generation of the tray discharge command, and the detection means detects the generation of the tray discharge command.
When it is hit, the pickup will be sent to the designated standby position.
The control means for controlling the feed motor, and the elastic conductive member for elastically contacting the pickup and grounding the pickup when the pickup is moved to the standby position by the control means. A disc reproducing device characterized by. 3. The information recorded on the disc is read.
For picking up a pickup in the radial direction of the disc
Of the feed motor and the pickup in elastic contact
An elastic conductive member for grounding the pickup,
Inside the cabinet with a tray for mounting the disc
The control method of the disc player that can be inserted and removed freely
The tray is exposed from inside the cabinet.
And a step of sending the pickup to a predetermined standby position when it is detected that the tray is exposed from the cabinet by the detection step, and the sending step causes the pickup to move to the standby position. The step of contacting the elastic conductive member with the elastic conductive member to ground the pickup. 4. The information recorded on the disc is read.
For picking up a pickup in the radial direction of the disc
Of the feed motor and the pickup in elastic contact
An elastic conductive member for grounding the pickup,
Inside the cabinet with a tray for mounting the disc
The control method of the disc player that can be inserted and removed freely
Te, and sends the steps of detecting the occurrence of the tray ejection instruction for discharging the tray from within the cabinet, when the occurrence of the tray discharge instruction is detected by the detection step, the pickup to a predetermined standby position step And a step of grounding the pickup by bringing the pickup into contact with the elastic conductive member when the pickup is sent to the standby position by the sending step. Method.