JP2011069851A - Optical deflector, optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner capable of highly precisely making laser light incident on the reflection face of a polygon mirror downsized accompanying the downsizing of the optical scanner, and highly precisely irradiating a photoreceptor with the laser light. <P>SOLUTION: The optical deflector includes: a polygon mirror which deflects a light beam; a cover which covers at least the polygon mirror and has an open part through which the light beam passes; and a transparent plate which blocks up the open part. A ventilation port is provided at a position where the extended line of the rotary axis of the polygon mirror intersects with the cover, and the ventilation port has an adjustment member capable of adjusting an opening amount. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical deflector, an optical scanning device, and an image forming apparatus using a polygon mirror that deflects and reflects a light beam.

  Conventionally, an optical scanning device is generally used in an image forming apparatus such as a laser printer or a copying machine.

  As shown in FIG. 8, the optical scanning device 81 includes a light source 82 such as a laser diode that emits a light beam (light beam, laser, laser light) and a collimator lens that collimates the light beam 83 emitted from the light source 82. 84, a cylinder lens 85 (cylindrical lens) that narrows (condenses) the light beam 83 that has passed through the collimator lens 84 in the sub-scanning direction, and a polygon mirror that deflects and reflects the light 83 that has passed through the cylinder lens 85 in the main scanning direction. And an optical deflector 86 provided with 94, an fθ lens 88 for guiding the light beam 83 deflected and reflected by the polygon mirror 94 to the photosensitive member 87, a reflection mirror 89, and the like. That is, the light beam 83 emitted from the light source 82 is shaped by a lens group (collimator lens 84 and cylinder lens 84), deflected and reflected by the polygon mirror 94 of the optical deflector 86, and condensed by the fθ lens 88 to be photosensitive. An image is recorded on the body 87.

  In addition, the optical scanning device 81 includes a reflection mirror 90 and a detection sensor 91 for detecting the timing when the light beam 83 scans the surface of the photoconductor 87. The light source 82, the collimator lens 84, the cylinder lens 85, the optical deflector 86, the fθ lens 88, the reflection mirrors 89 and 90, and the detection sensor 91 are fixed to the housing 92.

FIG. 9 is a schematic cross-sectional view (cross-sectional view taken along line AA in FIG. 8) of the optical deflector 86 fixed to the housing 92 of the optical scanning device 81.
As shown in FIG. 9, the optical deflector 86 includes a metal substrate 93, a multistage cylindrical and ceramic fixed shaft 96 fixed to the substrate 93 by a plurality of screws 109, and the fixed shaft 96. And a cover 108 in which an opening (not shown) through which the light beam 83 emitted from the light source 82 of the optical scanning device 81 passes is formed. The opening is closed by a transparent plate (not shown) so that dust or the like does not enter the cover from the outside of the cover.

  The rotating body 97 is fixed to a sleeve 98 inserted with a gap with respect to the fixed shaft 96, a flange 95 fixed to the sleeve 98 by press fitting or the like, and an inner peripheral surface of the skirt portion 99 of the flange 95. The rotor magnet 100, which is a permanent magnet, a polygon mirror 94 placed on the top surface of the flange 95, a spring 101 placed on the top surface of the polygon mirror 94, and the spring 95 pressed against the flange 95 while being pressed downward. The pressing member 102 is fixed.

Since the spring 101 is pressed downward by the pressing member 102, the polygon mirror 94 is fixed by being pressed against the upper surface of the flange 95 by the elastic force generated by the spring 101.
Further, a ring-shaped motor core 103, which is fixed to the substrate 93 so as to face the rotor magnet 100 in the radial direction and is wound with a plurality of coils, is fixed with screws 109 or the like. The terminal of the coil is soldered to the wiring provided on the substrate 93.

Then, a driver IC (Integrated) mounted on the board 93 is used.
The coil of the motor core 103 fixed to the substrate 93 is excited by the electrical signal sent from the circuit 104) and the like, and the rotor magnet 100 facing the motor core 103 moves, so that the rotating body 97 rotates at high speed. The fixed shaft 96 and the sleeve 98 constitute a dynamic pressure air bearing.

  The optical deflector 86 is placed on the upper surface of a protrusion formed on the surface of the housing 92 of the optical scanning device 81. A plurality of through holes 105 are formed in the vicinity of the inside of the protrusion of the housing 92. A female screw 107 is formed on the substrate 93 at the position of the substrate 93 corresponding to the through hole 105. The through hole 105 and the female screw 107 are located on the vertical line. Then, the male screw 106 is inserted into the through hole 105 from the back surface of the housing 92, and the front end portion of the male screw 106 is screwed into the female screw 107 formed on the substrate 93 and tightened (screwed), thereby fixing the substrate 93 to the housing 92. is doing.

  The light beam 83 emitted from the light source 82 of the optical scanning device 81 passes through the collimator lens 84 and the cylinder lens 85 and is deflected by the polygon mirror 102 of the optical deflector 86. By the deflection of the light beam 83 by the light deflector 86, the surface of the photoconductor 87 is scanned and exposed with the light beam 83.

  The upstream scanning optical system until the light beam 83 emitted from the light source 82 enters the optical deflector 86 is called a pre-deflection optical system (upstream optical system), and the light deflected by the optical deflector 86. A downstream scanning optical system until the beam 83 scans and exposes the surface of the photoconductor 87 is referred to as a post-deflection optical system (downstream optical system).

  The direction in which the light beam 83 deflected by the light deflector 86 scans the photoconductor 87 (the moving direction of the light beam 83) is referred to as a main scanning direction. The direction in which the surface of the photoconductor 87 moves is the sub-scanning direction, which is a direction orthogonal to the main scanning direction.

  The optical scanning device 81 described above has to adjust the light beam 83 to the target position in order to form an image of the light beam 83 emitted from the light source 82 on the surface of the photoconductor 87. Since the mounting position of the polygon mirror 94 of the optical deflector 86 is fixed, the light source 82 and the lens group (collimator lens 84 and cylinder lens 85) of the conventional optical scanning device are respectively in the optical axis direction of the light beam 83. An adjustment function capable of adjusting (adjusting) in the vertical direction (vertical and horizontal) is required (for example, see Patent Documents 1 to 3).

JP 11-271653 A Japanese Patent Laid-Open No. 10-20225 JP 2001-281572 A

  In recent years, optical scanners have been increased in speed and size, and the thickness of the reflection surface of the polygon mirror of the optical deflector (the height dimension of the reflection surface that deflects and reflects the light beam) has been reduced. For this reason, in order for the light beam 83 emitted from the light source 82 to enter the polygon mirror 94 having a thin reflection surface, adjustment in the direction perpendicular to the optical axis direction (sub-scanning direction) is made more than in the past. Need to be highly accurate. However, providing a highly accurate adjustment function in the pre-deflection optical system has a problem of increasing the cost of the optical scanning device.

  Contrary to the polygon mirror described above, by widening the reflection surface of the polygon mirror (increasing the thickness of the reflection surface of the polygon mirror), the adjustment range of the optical axis adjustment by the pre-deflection optical system is expanded, and the pre-deflection optics A means that does not add a highly accurate adjustment function to the system can be adopted. However, this means has a problem that the material cost and processing cost of the polygon mirror are increased and the windage loss when the polygon mirror is rotated increases. Here, the windage loss refers to a loss of rotational energy generated when the rotating body rotates against friction due to the viscosity of air, or a loss of rotational energy caused by air resistance due to turbulent flow around the rotating body.

  The present invention has been made in view of the above problems, and even when the optical scanning device is downsized, the reflection surface of the polygon mirror whose thickness is reduced as a result of the downsizing is highly accurate. An object of the present invention is to provide an inexpensive optical deflector or the like provided with an adjustment function capable of entering a light beam.

(First invention)
According to a first aspect of the present invention, there is provided a polygon mirror formed with a plurality of reflecting surfaces that rotate together with or relative to an axis and reflect a light beam, a flange that rotates together with the polygon mirror, and a rotor magnet fixed to the flange And a motor core fixed in a radial direction opposite to the rotor magnet and wound with a coil, a cover that covers at least the polygon mirror and has an opening through which the light beam passes, and closes the opening. The present invention relates to an optical deflector including a transparent plate. A vent is provided at a position where an extension line of the rotation axis of the polygon mirror of the optical deflector intersects the cover, and the vent includes an adjustment member capable of adjusting an opening amount. Is.

  During rotation of the polygon mirror, the opening amount of the vent is adjusted (adjusted) by the adjusting member, so that the height direction of the polygon mirror of the optical deflector [sub-scanning direction, rotation axis direction (thrust direction) ] Can be adjusted. When the opening amount of the vent is zero (the vent is completely closed), the height position of the polygon mirror is the wind force generated in the cover by the rotation of the polygon mirror (the wind exerts on the object). The height position becomes the upper limit position. On the contrary, by increasing the opening amount of the vent hole (in a state where the vent hole is opened), the height position of the polygon mirror is lowered downward. In other words, the rotational position of the polygon mirror is a balance between the wind force generated by the rotation of the polygon mirror, the force acting on the rotating body due to the airflow flowing in from the vent, and the magnetic attractive force by the rotor magnet and motor core. Determined.

  The adjustment of the polygon mirror rotating in the height direction (sub-scanning direction, rotation axis direction (thrust direction)) of the optical deflector can be maintained at a position where it can be attracted to the motor core by the magnetic force of the rotor magnet of the optical deflector. Within the range of is preferable.

  With this configuration, the sub-scanning direction that is perpendicular to the optical axis direction of the light beam guided from the pre-deflection optical system (vertical direction) can be adjusted, so the position of the light beam that scans the photoconductor in the sub-scanning direction Adjustments can be made. Further, the highly accurate sub-scanning direction adjustment function of the pre-deflection optical system can be omitted or simplified. That is, a highly accurate and inexpensive optical scanning device can be provided.

(Second invention)
The optical scanning device according to the second invention is a light source that emits a light beam, a lens group that shapes the light beam emitted from the light source, and the light beam shaped by the lens group that deflects and reflects the light beam. An optical deflector is provided.

  With this configuration, it is possible to provide an optical scanning device that achieves the effects of the first invention and that is more accurate and less expensive than the prior art. That is, by using the optical deflector described above, it is possible to provide an optical scanning device capable of forming a highly accurate electrostatic latent image on the photosensitive member.

Here, the lens group refers to an optical component group including at least a lens. That is, not only a lens but a mirror may be included. Examples of the lens include a cylinder lens (cylindrical lens), a collimator lens, and an fθ lens. Moreover, as a mirror, a reflective mirror (folding mirror) etc. are illustrated.
The shaping of the light beam means changing the traveling direction of the light beam to a desired direction using a mirror or the like, or changing the shape of the light beam to a desired shape using a lens or the like.

  An electrostatic latent image is an image formed on the surface (photosensitive layer) of the photoconductor by charging. The specific resistance of the portion of the photoconductive layer irradiated with the laser beam decreases, and the surface of the photoconductor is charged. This is a so-called negative latent image formed by the remaining charge flowing while the portion of the charge not irradiated with laser light remains.

(Third invention)
An image forming apparatus according to a third aspect of the invention includes a photosensitive member and the optical scanning device of the second aspect that scans the photosensitive member with a light beam.
With this configuration, it is possible to provide an image forming apparatus capable of forming an image with higher image quality than the conventional one that exhibits the effects of the second invention.

  According to the present invention, it is possible to provide an optical deflector and an optical scanning device capable of forming a highly accurate electrostatic latent image on a photoconductor. In addition, an image forming apparatus capable of forming a high-quality image can be provided.

1 is a schematic diagram of an image forming apparatus according to the present invention. Example 1 1 is a schematic diagram of an optical scanning device according to the present invention. Example 1 The perspective view of the optical deflector which concerns on this invention. Example 1 FIG. 3 is an AA cross-sectional view of the optical deflector illustrated in FIG. 2. Example 1 FIG. 4 is a partially enlarged view of the optical deflector illustrated in FIG. 3. Example 1 FIG. 3 is an AA cross-sectional view of the optical deflector illustrated in FIG. 2. (Example 2) FIG. 4 is a partially enlarged view of the optical deflector illustrated in FIG. 3. Example 3 Schematic diagram of a conventional optical scanning device. The schematic diagram of the conventional optical deflector.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Image forming device)
FIG. 1 is a diagram showing an example of the configuration of an image forming apparatus 501 according to the present invention.
An image forming apparatus 501 shown in FIG. 1 is a so-called tandem type digital color printer using an electrophotographic system. The image forming apparatus 501 includes an image forming process unit 570 that forms an image corresponding to image data of each color, a control unit 580 that controls the operation of the entire image forming apparatus 501, and a personal computer (PC) 503 or a scanner, for example. An image processing unit 581 that performs predetermined image processing on image data received from the image reading device 504 or the like.

  The image forming process unit 570 has four image forming units 510Y, 510M, 510C, and 510K (hereinafter, collectively referred to as “image forming unit 510” collectively) at regular intervals in the vertical direction (substantially vertical direction). Are arranged in parallel. The image forming unit 510 includes a photosensitive drum 511 as an image holding member, a charging roll 512, a developing device 513, and a drum cleaner 514.

  Here, the charging roll 512 uniformly charges the surface of the photosensitive drum 511 with a predetermined potential. The developing device 513 holds a two-component developer composed of toner of each color of yellow (Y), magenta (M), cyan (C), and black (K) and a magnetic carrier in each of the image forming units 510. The electrostatic latent image formed on the photosensitive drum 511 is developed with each color toner. The drum cleaner 514 removes toner, paper dust, and the like attached on the photosensitive drum 511 by bringing a plate-like member into contact with the surface of the photosensitive drum 511, for example.

  Further, the image forming apparatus 501 is provided with the optical scanning device 1 that exposes the photosensitive drum 511 provided in each of the image forming units 510. The optical scanning device 1 acquires image data for each color from the image processing unit 581, and a light beam (laser light) whose lighting is controlled based on the acquired image data, on the photosensitive drum 511 of each image forming unit 510. Are respectively subjected to scanning exposure.

  In addition, a paper transport belt 530 that transports the paper 590 is disposed so as to move in contact with the photosensitive drum 511 of each image forming unit 510. The paper transport belt 530 is a film-like endless belt that electrostatically attracts the paper 590 and is circulated around a drive roll 532 and an idle roll 533.

  In addition, transfer rolls 531 are disposed inside the paper transport belt 530 and facing the respective photoconductive drums 511, and a transfer electric field is formed between the photoconductive drums 511, and on the paper 590, Each color toner image formed by each image forming unit 510 is sequentially transferred.

  Further, on the downstream side of each transfer roll 531, a static elimination lamp 515 that neutralizes the photosensitive drum 511 after the transfer is provided. A fixing device 540 is provided on the downstream side of the paper transport belt 530 in the paper transport direction to perform a fixing process on the unfixed toner image on the paper 590 by heat and pressure.

  Further, as a paper transport system, a paper storage unit 550 that stores the paper 590, a pickup roll 551 that picks up and transports the paper 590 stored in the paper storage unit 550 at a predetermined timing, and a transport roll that transports the fed paper 590. In 552, a registration roll 553 is provided for feeding the paper 590 to the paper transport belt 530 in accordance with the image forming operation.

  In addition, the paper discharge roll 554 that conveys the paper 590 fixed by the fixing device 540, and in the case of single-sided printing, the paper 590 is discharged toward the paper discharge stacking portion 591 provided in the upper part of the apparatus main body, and double-sided printing is performed. In this case, a reversing roll 555 or the like for feeding the paper 590 fixed on one side by the fixing device 540 toward the double-sided conveyance path 592 by reversing from the rotation direction toward the paper discharge stacking unit 591 is arranged. It is installed.

  In the image forming apparatus 501, the image forming process unit 570 performs an image forming operation under the control of the control unit 580. That is, the image data input from the personal computer 503, the image reading device 504, or the like is subjected to predetermined image processing by the image processing unit 581 and is supplied to the optical scanning device 1. In each image forming unit 510, lighting control is performed on the surface of the photosensitive drum 511 uniformly charged at a predetermined potential by the charging roll 512 based on the image data from the image processing unit 581 by the optical scanning device 1. Scanning exposure is performed with the light beam, and an electrostatic latent image is formed on the photosensitive drum 511.

  The formed electrostatic latent image is developed by the developing device 513, and a toner image of each color is formed on the photosensitive drum 511. When the formation of each color toner image in each image forming unit 510 is started, the sheet 590 taken out from the sheet storage unit 550 is conveyed by the sheet conveying belt 530, and each color toner is generated by the transfer electric field formed by the transfer roll 531. Images are sequentially transferred onto paper 590. Thereafter, the sheet is conveyed to the fixing device 540 and the unfixed toner image is fixed on the sheet 590, and then the sheet 590 is stacked on the discharge stacking unit 591.

(Optical scanning device)
Next, the basic configuration of the optical scanning device 1 according to the present invention will be described.
As shown in FIG. 2, the optical scanning device 1 includes a light source 2 such as a laser diode that emits a light beam 3, a collimator lens 4 that collimates the light beam 3 emitted from the light source 2, and a collimator lens 4. A cylinder lens 5 that narrows the light beam 3 that has passed through in the sub-scanning direction, a light deflector 6 that includes a polygon mirror 14 that deflects and reflects the light beam 3 that has passed through the cylinder lens 5 in the main scanning direction, and is deflected by the polygon mirror 14. It has an fθ lens 8 and a reflecting mirror 9 for guiding the reflected light beam 3 to the photoreceptor 7.

  Here, the main scanning direction refers to the moving direction of the light beam 3 when the light scanning device 1 irradiates the surface of the photoconductor 7 with the light beam 3. The sub-scanning direction is the moving direction of the surface of the photoconductor 7. The main scanning direction and the sub-scanning direction are orthogonal to each other.

  In addition, the optical scanning device 1 includes a reflection mirror 10 and a detection sensor 11 for detecting the timing when the light beam 3 scans the surface of the photoconductor 7. The light source 2, the collimator lens 4, the cylindrical lens 5, the optical deflector 6, the fθ lens 8, the reflection mirrors 9 and 10, and the detection sensor 11 are fixed to the housing 12.

  The light beam 3 emitted from the light source 2 provided in the optical scanning device 1 passes through the collimator lens 4 and the cylinder lens 5, enters the optical deflector 6, and is deflected. Due to the deflection of the light beam 3 by the light deflector 6, the surface of the photoconductor 7 is scanned and exposed with the light beam 3.

(Optical deflector)
Next, the configuration of the optical deflector 6 will be described in detail with reference to FIGS.
3 is a perspective view of the optical deflector according to the present invention, and FIG. 4 is a schematic sectional view of the optical deflector 6 fixed to the housing 12 of the optical scanning device 1 shown in FIG. 2 (A- in FIG. 2). FIG. 5 is a partially enlarged view in which the dotted line portion B of the optical deflector shown in FIG. 3 is enlarged.

  As shown in FIGS. 3 and 4, the optical deflector 6 includes a metal substrate 13, a multistage cylindrical shape fixed to the substrate 13 by a plurality of screws 29, and a ceramic fixed shaft 16 (outer diameter φ11 mm). −4 μm), a rotating body 17 rotatably supported through the fixed shaft 16, and a cover 28 having an opening 32 through which the light beam 3 emitted from the light source 2 of the optical scanning device 1 passes. It is composed of The opening 32 is closed by a transparent plate 33 made of glass or resin so that dust or the like does not enter the inside of the cover from the outside of the cover.

  Further, on the upper surface of the cover 28, a vent hole 30 that is a through hole that communicates the outside and the inside of the cover 28 is formed. The position of the vent 30 is a position where the extended line of the rotation axis of the polygon mirror 14 and the cover 28 intersect. An adjustment member 31 for adjusting the opening amount is provided on the vent hole 30. As shown in FIGS. 3 and 5, the adjustment member 31 includes a groove 35 and a flat plate 34 that can slide along the groove 35. By sliding the flat plate 34, the opening amount of the vent 30 can be adjusted, and the air flow flowing into the cover 28 can be adjusted.

  The rotating body 17 includes a ceramic sleeve 18 (inner diameter φ11 mm, outer diameter φ16 mm), a flange 15 fixed to the sleeve 18 by press fitting or the like, and an inner peripheral surface of the skirt portion 19 of the flange 15 by an adhesive or the like. A fixed rotor magnet 20 which is a permanent magnet, a polygon mirror 14 placed on the upper surface of the flange 15, a spring 21 placed on the upper surface of the polygon mirror 14, and press-fitted into the flange 15 while pressing the spring 21 downward. The pressing member 22 is fixed to the upper surface of the sleeve 18 with a screw or the like.

  The polygon mirror 14 is fixed by being pressed against the upper surface of the flange 15 by the elastic force generated by the spring 21 because the spring 21 is pressed downward by the pressing member 22. Further, a ring-shaped motor core 23 that is fixed to the substrate 13 so as to face the rotor magnet 20 in the radial direction (the radial direction of the fixed shaft) and is wound with a plurality of coils is fixed by screws, adhesives, or the like. . The coil terminals are soldered to the wiring provided on the substrate 13.

  The coil of the motor core 23 fixed to the board 13 is excited by the electrical signal sent from the driver IC 24 or the like mounted on the board 13, and the rotor magnet 20 facing the motor core 23 moves, whereby the rotating body 17 is moved. It rotates at high speed.

  The optical deflector 6 is placed on the upper surface of a protrusion formed on the surface of the housing 12 of the optical scanning device 1. A plurality of through holes 25 are formed in the vicinity of the inside of the protrusion of the housing 12. In the through hole 25, a female screw 27 is formed at the position of the substrate 13 corresponding to the through hole 25. The through hole 25 and the female screw 27 are located on the vertical line. Then, the male screw 26 is inserted into the through hole 25 from the back surface of the housing 12, and the front end portion of the male screw 26 is screwed into the female screw 27 formed on the substrate 13 and tightened (screwed), thereby fixing the substrate 13 to the housing 12. is doing.

(Polygon mirror rotation height position adjustment method)
Next, a method for adjusting the rotational height position of the polygon mirror will be described.
First, the rotating body 17 of the optical deflector 6 is rotated with the vent hole 30 closed. Then, the air in the upper portion of the rotating body 38 moves in the radial direction around the rotation axis of the rotating body 17 (substantially the same as the rotation axis of the polygon mirror) by centrifugal force. The amount of air that moves gradually increases as the number of rotations of the rotating body 17 increases, so that the density (atmospheric pressure) of air in the cover 28 becomes lower at the upper part 38 of the rotating body (particularly on the rotating shaft), and the side of the cover The inner wall 39 is raised. For this reason, buoyancy acts on the rotating body 17, and the rotating body 17 floats upward. This buoyancy is maximized when the vent 30 is completely closed by the flat plate 34 of the adjusting member 31, that is, when the opening of the vent 30 is zero, and the height position at which the polygon mirror 14 rotates is the upper limit position. .

  Here, the “upper limit position” refers to the position of the maximum height in which the buoyancy generated by the rotation of the rotating body 17 and the magnetic attractive force of the rotor magnet 20 and the motor core are balanced. The rotating body 17 tends to float upward by buoyancy generated by the rotation of the polygon mirror 14. On the other hand, since the rotor magnet 20 and the motor core are attracted by the magnetic attraction force, the current state is maintained, that is, an attempt is made to pull back the floating body 17 from rising.

  Next, the flat plate 34 is moved to adjust the opening amount of the vent 30. As described above, since the air pressure in the upper part of the rotating body 38 in the cover 28 is lower than the atmospheric pressure outside the cover 28, the opening amount of the vent 30 is increased (the flat plate 34 is slid to open the vent). Then, air outside the cover flows into the cover 28 from the vent 30. When the opening amount of the air vent 30 is gradually increased to increase the inflow amount of the air outside the cover, the air pressure of the rotating body upper portion 38 that has been reduced gradually increases, and the buoyancy acting on (generating) the rotating body 17. Will decline. Accordingly, the rotational height position of the polygon mirror 14 is lowered downward.

  That is, by adjusting (increasing / decreasing) the opening amount of the vent 30, the balance position of the buoyancy generated by the rotation of the polygon mirror 14 and the magnetic attraction force by the rotor magnet 20 and the motor core, that is, the rotation of the polygon mirror 14 is performed. It is possible to adjust the height position in the sub-scanning direction.

  The adjustment of the opening amount of the vent 30 by the movement of the flat plate 34 is preferably performed in a state where the optical deflector 6 is attached to the optical scanning device 1, and the light beam emitted from the optical scanning device 1 causes the photosensitive member to be adjusted. It is more preferable to carry out while looking at the scanning position. When the light beam comes to manipulate the desired position, finally, the flat plate 34 is fixed using an adhesive or the like. If it does so, when a rotary body rotates, the above-mentioned balance state of buoyancy and magnetic attraction can be reproduced.

  As described above, the optical deflector 6 according to the present invention has the polygon mirror 14 in the sub-scanning direction which is a direction (vertical direction) perpendicular to the optical axis direction of the light beam 3 guided from the pre-deflection optical system. The rotating height position can be adjusted. For this reason, the highly accurate adjustment function of the sub-scanning direction of the pre-deflection optical system can be omitted or simplified. That is, a highly accurate and inexpensive optical scanning device can be provided.

FIG. 6 shows an embodiment according to the present invention.
FIG. 6 is a schematic cross-sectional view of the optical deflector fixed to the housing of the optical scanning device.
Note that portions similar to those of the optical deflector of the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only differences from the first embodiment will be described in detail.

  The main difference between the second embodiment and the first embodiment is that an adjusting member 31 is provided in a shaft rotation type optical deflector including a rotation shaft 37 on which a shaft rotates. Even with this configuration, the same effect as in the first embodiment can be obtained.

FIG. 7 shows an embodiment according to the present invention.
FIG. 7 is a partially enlarged view of the adjusting member provided on the upper part of the vent formed in the upper surface of the cover of the optical deflector according to the present invention.
Note that portions similar to those of the optical deflector of the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only differences from the first embodiment will be described in detail.

  The main difference from the first embodiment is that the adjusting member provided at the upper part of the vent of the optical deflector is formed by a diaphragm blade 36 in which a plurality of plates are overlapped. The shape of the opening formed when the vent hole 30 is blocked by the diaphragm blades 36 may be circular or rectangular. With the configuration as described above, it is possible to achieve the same effects as in the first embodiment.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto, and those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. As long as it is not contrary to the technical idea of the present invention, it can be changed, deleted and added.

  For example, in the above-described embodiment, not only the illustrated outer magnet type (outer rotor type) but also the inner magnet type (inner rotor type) may be applied to the motor that rotationally drives the rotating body.

  In the embodiment, resin caps having different vent sizes may be prepared and fitted in advance as vent adjustment members formed on the upper surface of the cover.

  Further, in the embodiment, the position of the vent hole does not have to be on the rotation axis, and may be anywhere as long as it communicates with the upper space of the rotating body.

  In the embodiment, a mechanism that allows the upper surface of the cover to move up and down may be used as means other than the vent. Since the pressure applied to the upper surface of the polygon mirror can be adjusted by moving the upper surface of the cover up and down, the same effect as the means by opening and closing the vent can be achieved.

  Furthermore, in the above-described embodiment, the transparent plate may be a transparent plate made of a transparent resin such as glass or PMMA (polymethyl methacrylate resin).

  Further, the present invention can be grasped as follows when the invention according to claim 1 is the first invention, the invention according to claim 2 is the second invention, and the invention according to claim 3 is the third invention.

(Fourth invention)
An optical deflector according to a fourth invention is the optical invention according to the first invention, wherein the vent is provided with a detachable filter means.

  Since the filter means is attached to the outside of the cover provided in the optical deflector, it can be easily attached to and detached from the cover.

  With this configuration, the same effect as that of the first invention can be obtained. Further, dust or the like contained in the air sucked from the vent can be prevented from entering the cover of the optical deflector. That is, if the sheet provided in the filter means is periodically exchanged according to the frequency of use of the optical scanning device, the inside of the cover of the optical deflector can always be kept clean with no dust.

  The present invention is applied to an optical deflector, an optical scanning device using the optical deflector, and an image forming apparatus using the optical scanning device.

DESCRIPTION OF SYMBOLS 1,81 ... Optical scanning device, 2,82 ... Light source, 3,83 ... Laser beam,
4, 84 ... Collimator lens, 5, 85 ... Cylinder lens, 6, 86 ... Optical deflector,
7, 87 ... photosensitive member, 8, 88 ... fθ lens, 9, 89 ... reflection mirror,
10, 90 ... reflective mirror, 11, 91 ... detection sensor, 12, 92 ... housing,
13, 93 ... substrate, 14, 94 ... polygon mirror, 15, 95 ... flange,
16, 96 ... fixed shaft, 17, 97 ... rotating body, 18, 98 ... sleeve,
19,99 ... skirt part, 20,100 ... rotor magnet,
21, 101 ... Spring, 22, 102 ... Pressing member, 23, 103 ... Motor core,
24,104 ... driver IC, 25,105 ... through hole,
26, 106 ... male screw, 27, 107 ... female screw, 28, 108 ... cover,
29,109 ... screw, 30 ... vent, 31 ... adjusting member, 32 ... opening,
33 ... Transparent plate, 34 ... Flat plate, 35 ... Groove, 36 ... Diaphragm blade, 37 ... Rotating shaft,
38 ... upper part of rotating body, 39 ... inner wall part of cover side surface,
501 ... Image forming apparatus, 510 ... Image forming unit,
570 ... Image forming process section,

Claims (3)

A polygon mirror formed with a plurality of reflecting surfaces that rotate together with or relative to an axis and reflect a light beam;
A flange that rotates with the polygon mirror;
A rotor magnet fixed to the flange;
A motor core fixed to face the rotor magnet in the radial direction and wound with a coil;
A cover that covers at least the polygon mirror and has an opening through which the light beam passes;
In an optical deflector comprising a transparent plate closing the opening,
A vent is provided at a position where an extension line of the rotation axis of the polygon mirror intersects the cover,
The vent is provided with an adjusting member capable of adjusting an opening amount. A light source that emits a light beam;
A lens group for shaping a light beam emitted from the light source;
The optical scanning device comprising the optical deflector according to claim 1, wherein the optical beam shaped by the lens group is deflected and reflected. A photoreceptor,
An image forming apparatus comprising the optical scanning device according to claim 2, wherein an electrostatic latent image is formed on the photoconductor.