JP3341561B2 - Light deflection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflecting device, and more particularly, to an optical deflecting device used in a copying machine, a facsimile machine, a laser printer, and the like, and rotatable about an axis on a base and in an axial direction. The present invention relates to a light deflecting device that deflects light by rotating a movable rotating body.

[0002]

2. Description of the Related Art A conventional light deflecting device (surface-facing light deflecting device) used for a copying machine, a facsimile machine, a laser printer, and the like includes a rotating body 54 as shown in FIG. The rotating body 54 is provided with a rotating polygon mirror 18 for deflecting a laser beam for main scanning and a drive magnet 56 for rotating the rotating body 54. In addition, the optical deflecting device rotatably supports the rotating body 54 in a non-contact manner via a dynamic pressure bearing 60 fixed to the housing 58. The rotating body 54 is supported by a magnetic bearing 62 so that it does not move up and down in the axial direction and does not contact the dynamic pressure bearing.

Further, the light deflecting device includes a driving magnet 56.
The printed circuit board 64 is disposed at a position facing the axial direction. At the position facing the drive magnet 56 in the axial direction and on the side of the drive magnet 56 of the printed board 64 (the upper side in the axial direction of the printed board 64), as shown in FIG. The formed comb-like power generation line 77 is provided, and the opposite side (the printed circuit board 64) is provided.
14 (a), as shown in FIG.
A group of stator coils made up of a group of stator coils 66, and a magnet position detector 68 which is formed of Hall elements every other one of the stator coils 66 and detects the position of the magnetic pole of the drive magnet 56 is arranged in the stator coils 66. Have been.

In the optical deflecting device having such a configuration, an N-pole and an S-pole are alternately generated in each of the stator coils 66 in sequence by applying an alternating current to each of the stator coils 66 with a phase shift. S pole and N pole of drive magnet 56,
The rotating magnet 54 is rotated by the magnetic force with the S pole, and the driving magnet 5 detected by the magnet position detector 68
Based on the positions of the magnetic poles 6 (N pole, S pole), the current flowing through the stator coil 66 is controlled by turning on and off a power transistor (not shown) so that the drive magnet 56 rotates further.

Here, in order to deflect the laser beam and perform main scanning, it is necessary to control the current flowing through the stator coil 66 so that the rotation speed of the rotating body 54 is constant.

For this reason, the light deflecting device is provided with
7, a portion 77a is formed radially around the axis of the rotating body, and the voltage generated in the comb power generation line 77 due to the crossing of the magnetic flux of the drive magnet 56 is detected as a speed detection signal.

Here, as described above, the rotating body 54, which is supported by the magnetic bearing 62 so as not to move up and down in the axial direction, is separated by a predetermined distance between the comb power generating line 77 and the driving magnet 56. To rotate at the correct position
Thus the comb generator line 77, the voltage of the waveform H ₁ shown in FIG. 17 (a) (speed detection signal) is derived.

Then, the optical deflector converts the speed detection signal into a digital signal at a certain threshold level 23, as shown in FIG. 17 (b), and compares the digital signal with the reference signal. By controlling the current flowing through the stator coil 66 so that the digital signal matches the reference signal, the rotation speed of the rotating body 54 is kept constant.

FIG. 15 is a cross-sectional view of a surface-facing optical deflector having a general magnet dedicated to speed detection. In this optical deflector, the upper surface of the printed circuit board 64 is also shown in FIG.
6 (b), a comb power generation line 77 is provided,
As shown in FIG. 16A, the lower surface of the printed circuit board 64 has a stator coil 66 and a magnet position detector 68.
Are arranged.

[0010]

However, the above-mentioned optical deflector supports the rotating body 54 rotatably via the dynamic pressure bearing 60 and uses the magnetic bearing 62 to prevent the rotating body 54 from moving up and down in the axial direction. Although supported, the rotating body 54
Since it is a non-contact rotating body 54 by the magnetic bearing 62 or the like
There is a limit to preventing vertical movement in the axial direction.

As a result, the rotating body 54 vertically moves (vibrates) in the axial direction. This vertical movement (vibration) causes the rotating body 54
The distance between the drive magnet 56 provided in the shaft and the interdigital power generation line 77 printed at a position facing the axial direction also changes continuously, and the magnetic flux between the drive magnet 56 and the interdigital power line 77 also changes. Will be.

[0012] Here, when the rotating body 54 is raised from the normal position, as shown in FIG. 17 (a), the voltage waveform H ₂ induced in the interdigital power line 77, the rotating body is a normal position The amplitude is smaller than when it is located.

The voltage waveform H whose amplitude has been reduced in this way
₂ is converted to a digital signal at a threshold level 23, as shown in FIG.
It differs from the actual rotation information (period). That is, even if the rotating body 54 originally rotates at a constant speed, the period of the digital signal fluctuates due to the vertical movement (vibration) of the rotating body 54 in the axial direction, and it is detected that the rotating body 54 is rotating irregularly. However, since speed control is performed based on this digital signal, there is a problem that stable rotation cannot be obtained as a result.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide an optical deflector capable of rotating a rotating body at a constant speed regardless of the axial movement of the rotating body. .

[0015]

According to the first aspect of the present invention, there is provided a rotating body rotatable on an axis on a base and movable in an axial direction, and rotating the rotating body. A rotating unit, a magnetic flux generating unit fixed to one of the rotating body and the base and generating a magnetic flux, and a magnetic flux generated by the magnetic flux generating unit intersected by the rotation of the rotating body, whereby an axis of the rotating body is rotated. Induced voltage generating means fixed to the other of the rotating body and the base so that an induced voltage having a constant amplitude waveform is generated regardless of movement in the direction,
Control means for controlling the rotating means so that the rotating body rotates at a constant speed based on a cycle obtained from a waveform of the induced voltage generated by the induced voltage generating means.

According to a second aspect of the present invention, in the first aspect of the invention, the magnetic flux generating means is fixed to the rotating body, and the induced voltage generating means is fixed to the base and extends in the axial direction. Is a voltage guide line that is longer than the axial length of the movable range of the magnetic flux generating means accompanying the movement of the rotating body.

According to a third aspect of the present invention, in the first aspect, the magnetic flux generating means is fixed to the rotating body, the induced voltage generating means is fixed to the base, and the rotating body is The magnetic flux generation including the upper end of the magnetic flux generating means including the lower end of the magnetic flux generating means when moving to the upper limit in the direction and the upper end of the magnetic flux generating means when the rotating body moves to the lower limit in the axial direction. It is a voltage induction wire fixed at a position corresponding to a region between the axial lower ends of the means.

According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the induced voltage generating means includes a printed circuit board on which the voltage induction lines are printed. I do.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the non-magnetic material or the non-magnetic material and the non- magnetic material are processed while supporting the induced voltage generating means. characterized in that it consists of a plane and further comprising the rotating body and support means fixed to the other of said base.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the rotating means is fixed to the rotating body and a magnetic flux for rotating the rotating body. And a driving unit that rotates the rotating body by a magnetic force between the rotating magnetic flux generating unit and the rotating magnetic flux generating unit, wherein the number of magnetic poles of the magnetic flux generating means is larger than the number of magnetic poles of the rotating magnetic flux generating means. It is characterized by.

Here, the rotating body according to the first aspect of the present invention is configured to be rotatable on an axis on the base and movable in the axial direction. Then, the rotating body is rotated by the rotating means.

Here, a magnetic flux generating means for generating a magnetic flux is fixed to one of the rotating body and the base. The magnetic flux generating means is fixed to the other of the rotating body and the base, that is, the magnetic flux generating means is fixed to the base when the magnetic flux generating means is fixed to the rotating body.
In this case, the induced voltage generating means is fixed to the rotating body. Then, the induced voltage generating means generates an induced voltage having a constant amplitude waveform irrespective of the axial movement of the rotating body due to the magnetic flux generated by the magnetic flux generating means intersecting with the rotation of the rotating body.

Here, when the magnetic flux generating means is fixed to the rotating body, the induced voltage generating means is fixed to the base and has a length in the axial direction. The voltage guide line may be longer than the axial length of the movable range of the magnetic flux generating means accompanying the movement of the rotating body.

As described above, the induced voltage generating means is fixed to the base and the axial length is equal to or more than the axial length of the movable range of the magnetic flux generating means accompanying the movement of the rotating body. Then, even if the magnetic flux generating means moves within the movable range along with the movement of the rotating body, the total number of magnetic fluxes generated by the magnetic flux generating means crossing the voltage induction line does not change. An induced voltage having a constant amplitude waveform is generated.

Similarly, when the magnetic flux generating means is fixed to the rotating body, the induction voltage generating means is fixed to the base and the rotating body is fixed at the upper limit in the axial direction. In the axial direction of the magnetic flux generating means including the lower end of the magnetic flux generating means when moved to the lower end of the magnetic flux generating means including the upper end of the magnetic flux generating means when the rotating body moves to the lower limit in the axial direction. A voltage induction wire fixed at a position corresponding to the region between the sides may be used.

As described above, the induction voltage generating means is fixed to the base, and the upper end of the magnetic flux generating means in the axial direction, including the lower end of the magnetic flux generating means when the rotating body moves to the upper limit in the axial direction, and the rotating body. If the voltage guide line is fixed at a position corresponding to a region between the lower end of the magnetic flux generating means and the lower end of the magnetic flux generating means including the upper end of the magnetic flux generating means when moved to the lower limit in the axial direction, the rotating body moves. Even when the magnetic flux generating means moves within a movable range, the total number of magnetic fluxes generated by the magnetic flux generating means crossing the voltage induction line does not change, and an induced voltage having a constant amplitude waveform is generated in the voltage induction line.

On the other hand, when the magnetic flux generation means is fixed to the base and the induction voltage generation means is fixed to the rotating body, the induction voltage generation means is a voltage induction wire, and the length of the magnetic flux generation means in the axial direction is small. The length may be equal to or longer than the axial length of the movable range of the voltage guide line along with the axial movement of the rotating body.

Similarly, when the magnetic flux generating means is fixed to the base and the induced voltage generating means is fixed to the rotating body, the induced voltage generating means is a voltage induction wire, and the rotating body is at the upper limit in the axial direction. The axial upper end of the voltage induction line including the lower end of the voltage induction line when moved and the axial lower end side of the voltage induction line including the upper end of the voltage induction line when the rotating body moves to the axial lower limit. The magnetic flux generating means may be fixed in a region corresponding to the region between the two.

The control means controls the rotating means so that the rotating body rotates at a constant speed based on a cycle obtained from the waveform of the induced voltage generated by the induced voltage generating means.

As described above, since the generated magnetic fluxes intersect by the rotation of the rotating body, an induced voltage having a constant amplitude waveform is generated regardless of the axial movement of the rotating body, and the period obtained from the generated induced voltage waveform is obtained. , The rotator rotates at a constant speed, so that the rotator can rotate at a constant speed.

Further, the induced voltage generating means may be configured to include a printed circuit board on which voltage induced wires are printed, as in the fourth aspect of the present invention.

As described above, if the induced voltage generating means is configured to include the printed circuit board on which the voltage induction lines are printed, the induced voltage generating means can be simplified.

Further, as in the fifth aspect of the present invention, the rotating body, which supports the induced voltage generating means and is made of a non-magnetic material or a magnetic material and a non-conductive treated surface , is used. A support means fixed to the other side of the base may be further provided.

As described above, if the supporting means for supporting the induced voltage generating means is provided, the induced voltage generating means can be stabilized and the supporting means can be made of a non-magnetic material or
If it is composed of a magnetic material and a non-conductive treated surface , the magnetic flux generated by the magnetic flux generating means does not change and crosses the induction voltage means, and the voltage induced by the induction voltage means does not change and has a constant amplitude. A waveform induced voltage can be generated.

According to a sixth aspect of the present invention, the rotating means includes a rotating magnetic flux generator fixed to the rotating body and generating a magnetic flux for rotating the rotating body; And a driving unit that rotates the rotating body by the magnetic force between the magnetic flux generating means, and the number of magnetic poles of the magnetic flux generating means may be larger than the number of magnetic poles of the rotating magnetic flux generating means.

As described above, the rotating magnetic flux generating section for generating the magnetic flux for rotating the rotating body is provided, and the rotating body is rotated by the magnetic force between the rotating magnetic flux generating section and the rotating magnetic flux generating means. Since the number of magnetic poles of the means is larger than the number of magnetic poles, for example, when an induced voltage having a constant amplitude waveform is generated in the induced voltage generating means by the magnetic flux generating means, the case where the rotating body is rotated by the magnetic force between the common magnetic flux generating means and In comparison, the cycle per rotation of the rotating body obtained from the waveform of the induced voltage generated by the induced voltage generating means is increased, and control is performed so that the rotating body rotates at a constant speed based on the obtained cycle. The speed can be controlled precisely from.

[0037]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a cross section of a laser printer provided with an optical deflecting device (surface-facing optical deflecting device) 10 according to this embodiment, and FIG. 2 shows a scanning system of the laser printer.

The scanning system of the laser printer includes a semiconductor laser 14, an optical system 16 for collimating the light beam from the semiconductor laser 14, and a light beam from the semiconductor laser 14 deflected at a constant angular velocity in a direction corresponding to the main scanning direction. The optical deflecting device 10 is provided. The scanning system of the laser printer applies a light beam deflected by the light deflector 10 at a constant angular velocity in a direction corresponding to the main scanning to a drum (photoconductor) 24.
An fθ lens 20 for forming an image on the upper surface and performing main scanning at a constant speed on the drum 24 is provided. Further, a reflection mirror 22 for reflecting the beam toward the scanning line position on the drum 24 is provided in the optical path of the light beam that has passed through the fθ lens 20.

On the other hand, the laser printer has a magazine 28 in which a plurality of sheets are stored in an overlapping manner. In the vicinity of the paper outlet of the magazine 28, a cam 30, a roller 32
Is arranged, and the cam 30 moves to the roller 32 side to take out the sheet from the magazine 28 for a predetermined length. A guide plate 34 that guides the sheet taken out from the cam 30 and the roller 32 once in the vertical direction and then in the horizontal direction is disposed downstream of the cam 30 and the roller 32 in the sheet conveyance direction.

Further, a roller 36 and a guide plate 38 are arranged on the downstream side of the guide plate 34 in the sheet transport direction, and guide the sheet to the development transfer unit 26.

The development transfer section 26 includes a charging corotron for charging the drum 24 in advance, a developing device for developing the latent image written on the drum 24 to form a toner image, and a polarity of the charge of the toner image on the drum 24. A transfer pretreatment corotron for aligning and removing charges on the drum 24 is provided. The development transfer unit 26 includes a transfer corotron for transferring the toner image on the drum 24 to the sheet, a charge removing corotron for peeling off the sheet electrostatically attracted to the drum 24, a cleaner for removing the residual toner on the drum 24, and and a charge removing lamp for removing a residual charge. The drum 24
Is rotated (sub-scanning) in a direction orthogonal to the main scanning direction of the light beam by a driving unit (not shown).

A guide plate 40 for guiding a sheet on which an image has been formed by the development transfer unit 26 to a charge removal device 42 for removing the charge of the sheet is disposed downstream of the development transfer unit 26 in the sheet transport direction. ing.

A guide plate 44, a roller 46, a guide plate 48, and a roller 50 are sequentially disposed downstream of the charged charge removing device 42 in the sheet conveying direction. The paper is guided to a tray 52 that stores the formed paper.

Next, the structure of the light deflecting device 10 will be described in more detail with reference to FIG. The light deflecting device 10 includes a rotating body 5 rotatably supported in a non-contact manner about a dynamic pressure bearing 60 fixed to a housing 58 together with the rotating polygon mirror 18.
4 is provided. Note that the non-contact support of the rotating body 54 in the axial direction is performed by a magnetic bearing 62. Dynamic pressure bearing 60
And between the rotary member 54, the scan <br/> Lee Bed 74 constituting the bearing function is arranged. The driving magnet 56 is provided we are in the rotary member 54, printed circuit board 64 is provided in a position facing the driving magnet 56 and the axial direction, the axial direction lower side of the printed circuit board 64, the stator coil 66
And magnet position detector 6 composed of Hall elements and the like
8 are provided.

As shown in FIG. 4, a balance adjusting member 72 for adjusting the weight balance of the rotating body 54 in the radial direction around the dynamic pressure bearing 60 is provided on the upper end of the light deflecting device 10. 74 and fixed by adhesion or the like. Hole 72 provided on the bottom surface of balance adjusting member 72
The inner diameter R ₇₂ of P is equal to or slightly larger than the inner diameter R _{74 of the} sleeve 74, and the balance adjusting member 72 is configured to be rotatable together with the rotating body 54. The sleeve 74 and the dynamic pressure bearing 60 are separated from each other by several [μm].

On the other hand, at a position around the dynamic pressure bearing 60 on the outer peripheral portion of the drive magnet 56, a non-magnetic material such as A
A cylindrical shaping member 70 made of BS resin or the like is provided. On the outer part (or inner part) of the cylindrical shaping member 70,
As shown in FIG. 5A, a comb-shaped power generation line 76 formed in a comb shape is fixed. Then, the rotation of the rotating body 54 rotates the four-pole drive magnet 56 shown in FIG. 5B, and the magnetic flux generated from the drive magnet 56 intersects with the comb-like power generation line 76, and the comb teeth A voltage is induced in the power line 76.

Here, the positional relationship between the comb-like power generation line 76 and the drive magnet 56 will be described. Although the rotating body 54 is supported in the axial direction by the magnetic bearing 62, the rotating body 54 also moves (vibrates) in the axial direction by the support of the magnetic bearing 62. Accordingly, the driving magnet 56 also moves (vibrates) in the axial direction as the rotating body 54 moves.

In this embodiment, the vibration width A of the drive magnet 56 axially vibrating and the length B of the electric wire portion effective for power generation of the comb-like power generation line 76 are the same or sufficiently long. That is, the axial length B of the electric wire portion effective for power generation of the comb-shaped power generation line 76
Is greater than or equal to the axial length A of the movable range of the drive magnet along with the movement of the rotating body 54 and is disposed at a position corresponding to the drive magnet 56 . Note that FIG. 5C shows a case where the axial length B of the electric wire portion effective for power generation of the comb-like power generation line 76 is the same as the axial length A of the movable range of the rotating body 54. ing.

As described above, if the positional relationship between the comb-shaped power generating line 76 and the driving magnet 56 is formed, even if the driving magnet 56 moves within a movable range with the movement of the rotating body 54, the driving magnet 56 The generated magnetic flux does not change the total number of magnetic fluxes crossing the interdigital power generation line 76, and an induced voltage having a constant amplitude waveform is generated in the interdigital power line 76.

The positional relationship between the comb-like power generation line 76 and the driving magnet 56 is not limited to this, and even if the driving magnet 56 vibrates in the axial direction as shown in FIG. And the length C of the electric wire portion effective for power generation is always located at a position where the electric wire portion effective for power generation faces the drive magnet 56.
May be provided. That is, the comb-shaped power generation line 76
The drive magnet 56 including the lower end 56D of the drive magnet 56 when the rotating body 54 moves to the upper limit in the axial direction.
Is fixed to a position corresponding to a region between the lower end in the axial direction of the drive magnet 56 and the upper end 56U of the drive magnet 56 when the rotating body 54 moves to the lower limit in the axial direction.

As described above, if the positional relationship between the comb-like power generating line 76 and the driving magnet 56 is formed, the rotating magnet 54 is moved by the driving magnet 56 even when the rotating magnet 54 moves within the movable range. The total number of magnetic fluxes crossing the interdigital power generation line 76 does not change, and an induced voltage having a constant amplitude waveform is generated in the interdigital power line 76.

Although the electric wire portion effective for power generation of the comb-shaped power generation line 76 is made parallel to the axial direction of the dynamic pressure bearing 60, the present invention is not limited to this.
The electric wire portion may be in a direction intersecting other than parallel to the axial direction.

Next, the control system of the present embodiment will be described with reference to FIG. As shown in FIG. 6, the control system includes a motor 78 including a drive magnet 56 and a stator coil 66.
And a motor drive circuit 88 for adjusting the amount and phase of the current supplied to the stator coil 66. The motor drive circuit 88 includes the magnet position detector 6 described above.
8 are connected.

The control system includes a speed detector 80 for detecting a voltage generated by the comb-shaped power generation line 76. The speed detector 80 includes a predetermined voltage detected by the speed detector 80. A waveform shaping circuit 82, which converts a digital signal at a threshold level into a digital signal, is connected.

Further, the waveform shaping circuit 82 is connected to a constant speed control circuit 84 which compares the digital signal with a reference signal from a reference signal generating circuit 86 and outputs a comparison value to a motor driving circuit 88.

Next, the operation of the present embodiment will be described. The operation of image development and transfer of the laser printer will be described.

The light beam emitted from the semiconductor laser 14 so as to correspond to the image to be recorded is collimated by the optical system 16. The collimated light beam is deflected by the light deflector 10 at a constant angular velocity in a direction corresponding to the main scanning direction. After that, the light beam passing through the fθ lens 20 is reflected by the reflection mirror 22 toward the scanning line position of the drum 24, forms an image on the drum 24, and
4 is main-scanned at a constant speed.

On the other hand, the sheet taken out of the magazine 28 from the roller 32 and the cam 30 is guided to the development transfer section 26 by the guide plate 34, the roller 36, and the guide plate 38.

The sheet developed and transferred by the developing and transferring section 26 is guided by the charge removing device 42 by the guide plate 40, and after the charge is removed, the guide plate 44, the roller 46,
The sheet is stored in the tray 52 by the guide plate 48 and the roller 50.

On the other hand, at the time of developing and transferring an image, the light deflecting device 10 causes an alternating current to flow through each of the stator coils 66 with the phase shifted, so that an N-pole and an S-pole are alternately generated in each of the stator coils 66 in order. The rotating body 54 is rotated by the magnetic force of the generated N and S poles and the N and S poles of the drive magnet 56, and the magnetic poles (N and S poles) of the drive magnet 7 detected by the magnet position detector 68 are detected. Based on the position, the current flowing through the stator coil 66 is controlled by turning a power transistor (not shown) on and off so that the drive magnet 56 further rotates. Thereby, the rotating body 54 rotates at a high speed.

Further, in the optical deflector 10, in order to deflect the laser beam and main-scan the drum 24 at a constant speed, the current flowing through the stator coil 66 is set so that the rotation speed of the rotating body 54 is constant. Control.

That is, the voltage having a constant amplitude waveform generated in the comb-shaped power generation line 76 is detected by the speed detector 80 and input to the waveform shaping circuit 82. In the waveform shaping circuit 82,
The input voltage having the constant amplitude waveform is converted into a digital signal at a predetermined threshold level and output to the constant speed control circuit 84. The constant speed control circuit 84 compares the reference signal input from the reference signal generation circuit 86 with the digital signal and outputs a comparison value to the motor drive circuit 88. The motor drive circuit 88 controls the current flowing through the stator coil 66 by turning on and off a power transistor (not shown) so that the reference signal matches the digital signal based on the input comparison value.

Here, as described above, since the induction voltage having a constant amplitude waveform is generated in the comb-like power generation line 76 as shown in FIG. 7A, the input is input to the waveform shaping circuit 82. The period of a digital signal obtained by digitally converting a voltage having a constant amplitude waveform at a predetermined threshold level is always constant, as shown in FIG.

Therefore, the cycle of the digital signal obtained by the waveform shaping circuit 82 matches the actual speed information of the rotating body 54 and is input to the constant speed control circuit 84, so that the motor 78 rotates at a constant speed. So that the rotating body 54 can be rotated at a high speed at a constant rotation speed.

Next, a second embodiment of the present invention will be described. The optical deflector 10 of the present embodiment is a radial gap type optical deflector as shown in FIG. 8, but has substantially the same configuration as that of the above-described first embodiment. Are denoted by the same reference numerals and description thereof is omitted,
The present embodiment differs from the first embodiment in that an armature coil 90 is used instead of the stator coil 66 of the first embodiment.
However, the difference is that the cylindrical shaping member 70 is disposed radially outside the dynamic pressure bearing 60.

In this embodiment, since the positional relationship between the drive magnet 56 and the comb-like power generating line 76 is the same as that of the first embodiment, the voltage of a constant amplitude waveform is applied to the comb-like power generating line 76. And the rotating body 54 can be rotated at a constant speed.

Next, a third embodiment of the present invention will be described. As shown in FIG. 9, the optical deflecting device of this embodiment has substantially the same configuration as the above-described surface-facing optical deflecting device of the first embodiment. The description is omitted, and only different portions will be described.

Drive magnet 5 provided on rotating body 54
6 is different from the drive magnet 56 in that a speed detection dedicated magnet 92 having a larger number of magnetic poles than the drive magnet 56 is disposed radially outside the dynamic pressure bearing 60 of the drive magnet 56.

As described above, separately from the driving magnet 56,
Since the speed detecting magnet 92 having a larger number of magnetic poles than the driving magnet 56 is arranged, the rotating body 54 is rotated by the magnetic force with the driving magnet 56 and a voltage having a constant amplitude waveform is generated on the comb tooth-shaped power generation line 76. The first
As compared with the second embodiment, the number of constant amplitude waveforms guided to the comb-like power generating line 76 per rotation of the rotating body 54 is increased, and the digital signal obtained from the obtained constant amplitude waveform is increased. Is controlled so that the rotating body 54 rotates at a constant speed on the basis of the cycle of the above, the speed can be precisely controlled.

As described above, since the number of constant amplitude waveforms guided to the comb-shaped power generating line 76 per one rotation of the rotating body 54 increases, the rotation speed is considered in consideration of the processing capability of the constant speed control circuit 84. The rotation speed of the body 54 is lower than the rotation speeds of the first and second embodiments described above.

In this embodiment, the driving magnet 56, the driving magnet 56 and the speed detecting magnet 92,
Since the positional relationship with the interdigital power generation line 76 is the same as that of the first embodiment, a voltage having a constant amplitude waveform is induced in the interdigital power line 76, and thus the rotating body 54 is driven at a constant speed. Can be rotated.

Here, when the cylindrical shaping member 70 is made of a magnetic material, the surface concentrically opposed to the speed detecting magnet 92 and concentrically opposed to the outer peripheral portion of the speed detecting magnet 92 is nonconductive. It may be processed and arranged, and the comb-like power generation line 10 may be fixed to this surface.

Next, a fourth embodiment of the present invention will be described. This embodiment is the first embodiment described above (see FIG. 3).
Since the configuration is substantially the same as that of the third embodiment (see FIG. 9), the same components are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described.

In the present embodiment, as shown in FIG.
4 or at a position facing the drive magnet 56 on the outer peripheral portion of the drive magnet 56 provided on the rotating body 54, or as shown in FIG.
In place of the cylindrical shaping member 70, a flexible substrate 94 on which a comb-like power generation line 76 is printed is fixed at a position facing the speed detection dedicated magnet 92 on the outer peripheral portion 2 as shown in FIG. I have.

As described above, in the present embodiment, the flexible board 94 on which the comb-like power generation lines 76 are printed is fixed instead of the cylindrical shaping member 70, so that the number of components can be reduced.

In this embodiment, the driving magnet 56 (in the case of FIG. 10), the driving magnet 56 and the speed detecting magnet 92 (in the case of FIG. 11),
Is the same as that of the first embodiment, a voltage having a constant amplitude waveform is induced in the comb-like power generation line 76, and therefore, the rotating body 54 can be rotated at a constant speed. .

In the first to fourth embodiments described above, the driving magnet is constituted by the permanent magnet.
The present invention is not limited to this, and may be configured by an electromagnet. Note that the above-described speed detection-dedicated magnet 92 may also be configured by an electromagnet.

In the first to fourth embodiments, the driving magnet, the driving magnet, and the speed detecting magnet are fixed to the rotating body, and the comb-like power generation line is fixed to the housing. The invention is not limited to this, and the drive magnet, the drive magnet, and the magnet dedicated to speed detection may be fixed to the housing, and the comb-shaped power generation line may be fixed to the rotating body.

[0079]

As described above, according to the present invention, when the magnetic fluxes generated by the rotation of the rotating body intersect, the induced voltage having a constant amplitude waveform is generated regardless of the axial movement of the rotating body. Since the rotating body rotates at a constant speed based on the cycle obtained from the waveform of the induced voltage, there is an effect that the rotating body can be rotated at a constant speed.

Further, if the induced voltage generating means is configured to include a printed circuit board on which voltage induction wires are printed, the induced voltage generating means can be simplified.

Further, by providing a supporting means for supporting the induced voltage generating means, the induced voltage generating means can be stabilized and the supporting means can be made of a non-magnetic material or a magnetic material and a non-conductive material. magnetic flux generating means is also not changed induced voltage by the will and the induced voltage means to cross the induced voltage means unchanged magnetic flux generated by if composed by surface, generates an induced voltage of constant amplitude waveform can do.

Further, a rotating magnetic flux generating section for generating a magnetic flux for rotating the rotating body is provided, and the rotating body is rotated by a magnetic force between the rotating magnetic flux generating section and the rotating magnetic flux generating means. Since the number of magnetic poles is larger than the number of magnetic poles, for example, when an induced voltage having a constant amplitude waveform is generated in the induced voltage generating means by the magnetic flux generating means, it is compared with the case where the rotating body is rotated by the magnetic force between the common magnetic flux generating means. Then, the cycle per rotation of the rotating body obtained from the waveform of the induced voltage generated by the induced voltage generating means increases, and the rotating body is controlled to rotate at a constant speed based on the obtained cycle. Speed control can be performed precisely.

[Brief description of the drawings]

FIG. 1 is a sectional view of a laser printer.

FIG. 2 is a diagram illustrating a scanning system of the laser printer.

FIG. 3 is a cross-sectional view of the light deflecting device according to the first embodiment.

FIG. 4 is an explanatory diagram illustrating the relationship between the sizes of a balance adjusting member, a sleeve, and a dynamic pressure bearing.

FIG. 5 is an explanatory diagram illustrating a positional relationship between a drive magnet and a comb-like power generation line.

FIG. 6 is a block diagram illustrating a control system according to the first embodiment.

FIG. 7 is a diagram illustrating a waveform of an induced voltage and a digital signal of the induced voltage of the optical deflection device according to the first embodiment.

FIG. 8 is a sectional view of a light deflecting device according to a second embodiment.

FIG. 9 is a sectional view of an optical deflecting device according to a third embodiment.

FIG. 10 is a sectional view of an optical deflection device according to a fourth embodiment.

FIG. 11 is a sectional view of another optical deflector according to the fourth embodiment.

FIG. 12 is a diagram showing a flexible substrate on which comb-like power generation lines are printed.

FIG. 13 is a sectional view of a conventional light deflecting device.

FIG. 14 is a diagram showing components arranged on the upper and lower surfaces of a printed circuit board of a conventional optical deflection device.

FIG. 15 is a sectional view of another conventional light deflecting device.

FIG. 16 is a diagram showing components arranged on the upper and lower surfaces of a printed circuit board of another conventional light deflecting device.

FIG. 17 is a diagram showing a waveform of an induced voltage and a digital signal of the induced voltage of the conventional optical deflection device.

[Explanation of symbols]

 58 Housing (base) 54 Rotating body 56 Driving magnet (magnetic flux generating means, rotating means) 66 Stator coil (rotating means) 88 Motor driving circuit (rotating means) 76 Comb-shaped power generation line (induced voltage generating means) 80 Speed detection (Control means) 82 waveform shaping circuit (control means) 86 reference signal generating circuit (control means) 84 constant speed control circuit (control means)

Claims (6)

(57) [Claims] A rotating body rotatable about an axis and movable in an axial direction on a base; rotating means for rotating the rotating body; fixed to one of the rotating body and the base; A magnetic flux generating means for generating a magnetic flux, and a magnetic flux generated by the magnetic flux generating means intersecting with the rotation of the rotating body so that an induced voltage having a constant amplitude waveform is generated regardless of the axial movement of the rotating body. An induced voltage generating means fixed to the other of the rotating body and the base, and the rotating body rotates at a constant speed based on a cycle obtained from a waveform of the induced voltage generated by the induced voltage generating means. An optical deflecting device comprising: a control unit that controls a rotating unit. 2. The magnetic flux generating means is fixed to the rotating body, and the induced voltage generating means is fixed to the base and the axial length of the magnetic flux generating means accompanying the movement of the rotating body. 2. The optical deflecting device according to claim 1, wherein the voltage guiding line is at least as long as the axial length of the movable range. 3. The magnetic flux generating means is fixed to the rotating body, and the induced voltage generating means is fixed to the base and lowers the magnetic flux generating means when the rotating body moves to the upper limit in the axial direction. A position corresponding to an area between the upper end of the magnetic flux generating means including the upper end of the magnetic flux generating means and the upper end of the magnetic flux generating means when the rotating body moves to the lower limit in the axial direction; 2. The optical deflecting device according to claim 1, wherein the light guiding device is a voltage guide wire fixed to the optical deflector. 4. The optical deflecting device according to claim 2, wherein the induced voltage generating means includes a printed circuit board on which the voltage induced line is printed. 5. A supporting means for supporting the induced voltage generating means and comprising a non-magnetic material or a magnetic material and a non-conductive treated surface and fixed to the other of the rotating body and the base. The optical deflecting device according to any one of claims 1 to 4, wherein: 6. A rotating magnetic flux generating section which is fixed to the rotating body and generates a magnetic flux for rotating the rotating body, and rotates the rotating body by a magnetic force between the rotating means and the rotating magnetic flux generating section. The optical deflector according to any one of claims 1 to 5, wherein the optical deflector is configured by a driving unit that drives the magnetic flux generating unit, wherein the number of magnetic poles of the magnetic flux generating unit is larger than the number of magnetic poles of the rotating magnetic flux generating unit.