JPH10111469A - Scanning optical device - Google Patents
Scanning optical deviceInfo
- Publication number
- JPH10111469A JPH10111469A JP8282999A JP28299996A JPH10111469A JP H10111469 A JPH10111469 A JP H10111469A JP 8282999 A JP8282999 A JP 8282999A JP 28299996 A JP28299996 A JP 28299996A JP H10111469 A JPH10111469 A JP H10111469A
- Authority
- JP
- Japan
- Prior art keywords
- fixed shaft
- dynamic pressure
- polygon mirror
- sleeve
- scanning optical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Mechanical Optical Scanning Systems (AREA)
- Sliding-Contact Bearings (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
- Dot-Matrix Printers And Others (AREA)
- Laser Beam Printer (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、レーザビームプリ
ンタやレーザファクシミリ等の画像形成装置に用いられ
る走査光学装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used for an image forming apparatus such as a laser beam printer and a laser facsimile.
【0002】[0002]
【従来の技術】図7は、レーザビームプリンタやレーザ
ファクシミリ等の画像形成装置に用いられる一般的な走
査光学装置を説明するもので、これは、光源ユニット5
0から発生された光ビームL0 をシリンドリカルレンズ
51によって回転多面鏡101の反射面に線状に集光さ
せ、回転多面鏡101の回転によって偏向走査し、結像
レンズ系52を経て図示しない回転ドラム上の感光体に
結像させる。結像レンズ系52は球面レンズ52a、ト
ーリックレンズ52b等によって構成され、前記感光体
に結像する点像の歪を補正する機能を有する。また、偏
向走査された光ビームの一部分は反射ミラー53によっ
て光ファイバ54の受光端に導入され、走査開始信号に
変換されて光源ユニット50に送信される。2. Description of the Related Art FIG. 7 illustrates a general scanning optical device used in an image forming apparatus such as a laser beam printer or a laser facsimile.
The light beam L 0 generated from 0 is condensed linearly on the reflecting surface of the rotating polygon mirror 101 by the cylindrical lens 51, and the light beam L 0 is deflected and scanned by the rotation of the rotating polygon mirror 101, and is rotated via the imaging lens system 52. An image is formed on the photosensitive member on the drum. The imaging lens system 52 includes a spherical lens 52a, a toric lens 52b, and the like, and has a function of correcting distortion of a point image formed on the photoconductor. A part of the light beam that has been deflected and scanned is introduced into the light receiving end of the optical fiber 54 by the reflection mirror 53, converted into a scanning start signal, and transmitted to the light source unit 50.
【0003】回転多面鏡101の駆動部は、図6に示す
ように、固定軸102に嵌合する回転スリーブ103に
フランジ部材103aを一体化してこれにロータマグネ
ット104を固着し、回転多面鏡101を押えバネ10
5によってフランジ部材103aに押圧してこれと一体
的に結合させるとともに、固定軸102を固定したモー
タハウジング106にモータ基板107を支持させたも
ので、モータ基板107上に立設されたステータ108
を励磁することで、ロータマグネット104と回転多面
鏡101を一体的に回転させる。As shown in FIG. 6, a driving section of the rotary polygon mirror 101 integrates a flange member 103a with a rotary sleeve 103 fitted on a fixed shaft 102, and fixes a rotor magnet 104 to the flange member 103a. Pressing spring 10
5, the motor substrate 107 is supported by a motor housing 106 to which the fixed shaft 102 is fixed while being pressed against the flange member 103a and integrally connected to the flange member 103a.
, The rotor magnet 104 and the rotary polygon mirror 101 are integrally rotated.
【0004】回転スリーブ103はその回転によって固
定軸102との間に空気膜を形成し、固定軸102に非
接触で回転する空気軸受を構成する。回転スリーブ10
3の下端には第1の永久磁石109aが固着され、永久
磁石109aはモータハウジング106と一体である第
2の永久磁石109bに対向しており、両永久磁石10
9a,109bの間に作用する磁気反撥力によって、回
転スリーブ103の下端をモータハウジング106に対
して非接触で支持するスラスト軸受を構成する。The rotating sleeve 103 forms an air film between itself and the fixed shaft 102 by its rotation, and forms an air bearing which rotates without contact with the fixed shaft 102. Rotating sleeve 10
The first permanent magnet 109a is fixed to the lower end of the third permanent magnet 109a. The permanent magnet 109a faces the second permanent magnet 109b integrated with the motor housing 106.
A thrust bearing for supporting the lower end of the rotary sleeve 103 in a non-contact manner with respect to the motor housing 106 is formed by the magnetic repulsion acting between 9a and 109b.
【0005】回転多面鏡101をフランジ部材103a
に押圧する押えバネ105は、回転スリーブ103の側
面に組み付けられた皿形のバネであり、その内周縁が回
転スリーブ103の環状溝に係止され、外周縁が回転多
面鏡101の上面に押圧される。The rotating polygon mirror 101 is connected to a flange member 103a.
The pressing spring 105 is a dish-shaped spring assembled to the side surface of the rotating sleeve 103, the inner peripheral edge of which is locked in the annular groove of the rotating sleeve 103, and the outer peripheral edge thereof is pressed against the upper surface of the rotating polygon mirror 101. Is done.
【0006】また、回転スリーブ103の開口端はふた
部材103bによって閉塞され、固定軸102の上端に
空気だまり110が形成される。回転スリーブ103の
固定軸102に対する軸方向の位置が変化すると、空気
だまり110内の空気が加圧または減圧され、回転スリ
ーブ103を元の位置に戻そうとする力が働く。このよ
うなエアダンパーの働きによって回転スリーブ103の
軸方向の変位を防ぎ、回転多面鏡101を安定して回転
させることができる。The opening end of the rotating sleeve 103 is closed by a lid member 103b, and an air reservoir 110 is formed at the upper end of the fixed shaft 102. When the position of the rotating sleeve 103 in the axial direction with respect to the fixed shaft 102 changes, the air in the air pool 110 is pressurized or decompressed, and a force acts to return the rotating sleeve 103 to the original position. By the function of such an air damper, displacement of the rotating sleeve 103 in the axial direction can be prevented, and the rotating polygon mirror 101 can be stably rotated.
【0007】[0007]
【発明が解決しようとする課題】しかしながら上記従来
の技術によれば、前述の空気軸受は、回転スリーブと固
定軸の間に形成される空気膜の動圧によって、両者を非
接触に保つものであるが、前記空気膜の動圧が安定せ
ず、このために回転スリーブが固定軸に接触してかじり
や摩耗が発生しやすいという未解決の課題がある。However, according to the above-mentioned prior art, the above-mentioned air bearing keeps both members out of contact by the dynamic pressure of an air film formed between the rotating sleeve and the fixed shaft. However, there is an unsolved problem that the dynamic pressure of the air film is not stable, and the rotating sleeve comes into contact with the fixed shaft to easily cause galling and wear.
【0008】空気軸受の動圧を安定させるためには、回
転スリーブの内面や固定軸の外周面にヘリングボーン溝
等の動圧発生溝等を設けて、軸受間隙の空気の流動を促
進するのが効果的であるが、ヘリングボーン溝等を固定
軸や回転スリーブに加工する工程が複雑で加工コストが
高い。In order to stabilize the dynamic pressure of the air bearing, a dynamic pressure generating groove such as a herringbone groove is provided on the inner surface of the rotating sleeve or the outer peripheral surface of the fixed shaft to promote the flow of air in the bearing gap. Is effective, but the process of forming the herringbone groove or the like into a fixed shaft or a rotating sleeve is complicated and the processing cost is high.
【0009】また、複雑な形状を有するヘリングボーン
溝等の替わりに、固定軸の外周面に周方向に等間隔で3
個の直線溝や帯状の平面部分を設けたものが開発されて
いる。これは切削等の公知の加工方法によって固定軸の
軸方向に3個の直線溝あるいは帯状の平面部分を加工す
るだけですむため、ヘリングボーン溝等のように加工コ
ストが高くなるおそれはない。各直線溝は、固定軸の円
筒面の所定の部位を軸方向に帯状に切除することによっ
て形成されたもので、切削量を少なくすれば、実質的に
1個あるいは複数の単一平面からなる帯状の平面部分と
なる。Further, instead of a herringbone groove having a complicated shape or the like, the outer peripheral surface of the fixed shaft is provided at equal intervals in the circumferential direction.
A device provided with individual straight grooves and a band-shaped flat portion has been developed. Since it is only necessary to machine three straight grooves or band-shaped flat portions in the axial direction of the fixed shaft by a known machining method such as cutting, there is no possibility that machining costs are increased as in the case of a herringbone groove. Each straight groove is formed by cutting a predetermined portion of the cylindrical surface of the fixed shaft in a band shape in the axial direction, and if the amount of cutting is reduced, it is substantially composed of one or a plurality of single planes. It becomes a band-shaped plane portion.
【0010】ところが、このように3個の直線溝等を固
定軸の外周面に形成すると、固定軸の真円度等の形状精
度が低い場合には、直線溝等の配設位置によって著しい
動圧分布が生じる。その結果、安定した軸受性能を得る
ための必要回転数が一定しないという不都合がある。However, when the three linear grooves and the like are formed on the outer peripheral surface of the fixed shaft as described above, when the accuracy of the shape such as the roundness of the fixed shaft is low, remarkable movement is caused by the arrangement position of the linear grooves. A pressure distribution occurs. As a result, there is an inconvenience that the required number of revolutions for obtaining stable bearing performance is not constant.
【0011】なお、一般的に空気軸受は、所定の軸受性
能を得るための必要回転数が低いほど軸受性能が安定
し、寿命が長くなることが知られている。In general, it is known that the lower the number of rotations required for obtaining a predetermined bearing performance, the more stable the bearing performance and the longer the life of the air bearing.
【0012】本発明は上記従来の技術の有する未解決の
課題に鑑みてなされたものであり、回転多面鏡を回転支
持する空気軸受が安定した軸受性能と優れた耐久性を有
し、しかも安価である走査光学装置を提供することを目
的とするものである。The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and an air bearing for rotatably supporting a rotary polygon mirror has stable bearing performance, excellent durability, and is inexpensive. It is an object of the present invention to provide a scanning optical device.
【0013】[0013]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明の走査光学装置は、互に嵌合して相対的に
回転自在である軸部材とスリーブ部材からなる空気軸受
と、前記軸部材またはスリーブ部材と一体的に結合され
た回転多面鏡と、該回転多面鏡を回転させる駆動手段を
有し、前記軸部材が、周方向に等間隔で少なくとも9個
の直線状の動圧発生溝を備えていることを特徴とする。In order to achieve the above object, a scanning optical device according to the present invention comprises: an air bearing comprising a shaft member and a sleeve member which are fitted to each other and are relatively rotatable; A rotating polygon mirror integrally connected to the shaft member or the sleeve member; and driving means for rotating the rotating polygon mirror, wherein the shaft member has at least nine linear movements at equal intervals in a circumferential direction. It is characterized by having a pressure generating groove.
【0014】[0014]
【作用】直線状の動圧発生溝は、軸部材の外周面を軸方
向に直線状に切除して直線溝や少なくとも1個の単一平
面からなる帯状の平面部分を形成するだけですむため、
加工が簡単で、へリングボーン溝等のように加工コスト
が高騰するおそれもない。このような直線状の動圧発生
溝を軸部材の周方向に等間隔で9個以上配設すると、軸
部材の真円度等が低く、例えば断面が楕円形状であって
も、軸部材の周方向にほぼ均一な動圧を発生させること
ができる。[Function] Because the linear dynamic pressure generating groove only needs to cut off the outer peripheral surface of the shaft member linearly in the axial direction to form a linear groove or a band-shaped flat portion composed of at least one single plane. ,
The processing is simple, and there is no possibility that the processing cost will rise as in the case of a herringbone groove. When nine or more such linear dynamic pressure generating grooves are provided at equal intervals in the circumferential direction of the shaft member, the roundness of the shaft member is low, and for example, even if the cross section is elliptical, the shaft member has A substantially uniform dynamic pressure can be generated in the circumferential direction.
【0015】その結果、空気軸受の軸受性能が安定し、
軸部材とスリーブ部材の間を非接触に保つための必要回
転数も低くなり、空気軸受の寿命が長くなる。As a result, the bearing performance of the air bearing is stabilized,
The number of rotations required to keep the shaft member and the sleeve member out of contact is also reduced, and the life of the air bearing is extended.
【0016】これによって、走査光学装置の回転多面鏡
の回転性能を向上させるとともに、走査光学装置の長寿
命化に大きく貢献できる。Thus, the rotation performance of the rotary polygon mirror of the scanning optical device can be improved, and the life of the scanning optical device can be greatly extended.
【0017】[0017]
【発明の実施の形態】本発明の実施の形態を図面に基づ
いて説明する。Embodiments of the present invention will be described with reference to the drawings.
【0018】図1は、一実施例による走査光学装置の主
要部を示すもので、これは光ビームを反射する反射面1
aを備えた回転多面鏡1を有し、その駆動部は、軸部材
である固定軸2にスリーブ部材である回転スリーブ3を
嵌合し、これと一体的に設けられたフランジ部材4にロ
ータマグネット5を固着し、押えバネ6によって回転多
面鏡1をフランジ部材4に押圧するとともに、固定軸2
を固定したモータハウジング7にモータ基板7aを支持
させ、これにステータ8を立設したもので、ロータマグ
ネット5とステータ8は、回転多面鏡1を回転させる駆
動手段であるモータを構成し、ステータ8を励磁するこ
とで、ロータマグネット5と回転多面鏡1を一体的に回
転させる。FIG. 1 shows a main part of a scanning optical device according to an embodiment, which is a reflecting surface 1 for reflecting a light beam.
a rotary polygon mirror 1 provided with a rotating shaft 3 as a sleeve member is fitted to a fixed shaft 2 as a shaft member, and a rotor is fitted to a flange member 4 provided integrally therewith. The rotary polygon mirror 1 is pressed against the flange member 4 by the holding spring 6 with the magnet 5 fixed thereto, and the fixed shaft 2 is fixed.
A motor substrate 7a is supported on a motor housing 7 on which is fixed, and a stator 8 is erected on the motor substrate 7a. The rotor magnet 5 and the stator 8 constitute a motor which is a driving means for rotating the rotary polygon mirror 1, and a stator When the magnet 8 is excited, the rotor magnet 5 and the rotary polygon mirror 1 are integrally rotated.
【0019】回転スリーブ3はその回転によって固定軸
2との間に空気膜を形成し、固定軸2に非接触で回転す
るラジアル空気軸受を構成する。回転スリーブ3の下端
には第1の永久磁石9aが固着され、永久磁石9aの下
面が、モータハウジング7に固定された第2の永久磁石
9bの上面に対向している。The rotary sleeve 3 forms an air film between itself and the fixed shaft 2 by its rotation, and constitutes a radial air bearing which rotates without contact with the fixed shaft 2. A first permanent magnet 9a is fixed to a lower end of the rotating sleeve 3, and a lower surface of the permanent magnet 9a faces an upper surface of a second permanent magnet 9b fixed to the motor housing 7.
【0020】また、第1の永久磁石9aの外周面は、モ
ータハウジング7に固定された第3の永久磁石9cの内
周面に対向している。第1、第2の永久磁石9a,9b
は回転スリーブ3の軸方向に互に磁極が逆向きになるよ
うに着磁されており、両者の磁気反撥力によって、回転
スリーブ3の下端をモータハウジング7に対して非接触
に支持するスラスト軸受を構成する。第3の永久磁石9
cは第1の永久磁石9aと同方向に着磁され、前記スラ
スト軸受に予圧を与えて回転スリーブ3の軸方向の位置
を安定させる働きをする。The outer peripheral surface of the first permanent magnet 9a faces the inner peripheral surface of the third permanent magnet 9c fixed to the motor housing 7. First and second permanent magnets 9a, 9b
The thrust bearing is magnetized so that the magnetic poles are opposite to each other in the axial direction of the rotating sleeve 3, and the lower end of the rotating sleeve 3 is supported in a non-contact manner with respect to the motor housing 7 by the magnetic repulsion of the two. Is configured. Third permanent magnet 9
c is magnetized in the same direction as the first permanent magnet 9a, and serves to apply a preload to the thrust bearing to stabilize the position of the rotary sleeve 3 in the axial direction.
【0021】すなわち、回転多面鏡1は、第1、第2の
永久磁石9a,9bの間に作用する磁気反撥力と第1、
第3の永久磁石9a,9cの間に作用する軸方向の付勢
力によって所定の高さに安定して非接触で支持される。In other words, the rotary polygon mirror 1 is provided with a magnetic repulsive force acting between the first and second permanent magnets 9a, 9b and the first,
The third permanent magnets 9a and 9c are stably supported at a predetermined height in a non-contact manner by an axial urging force acting between the third permanent magnets 9a and 9c.
【0022】また、回転スリーブ3の開口端は、ふた部
材10によって閉塞され、固定軸2の上端に空気だまり
10aを形成する。回転スリーブ3の固定軸2に対する
軸方向の位置が変化すると、空気だまり10a内の空気
が加圧または減圧され、回転スリーブ3を元の位置に戻
そうとする力が働く。このようなエアダンパーの働きに
よって回転スリーブ3の軸方向の変位を防ぎ、回転多面
鏡1を安定して回転させることができる。The open end of the rotating sleeve 3 is closed by a lid member 10 to form an air reservoir 10a at the upper end of the fixed shaft 2. When the position of the rotating sleeve 3 in the axial direction with respect to the fixed shaft 2 changes, the air in the air pool 10a is pressurized or decompressed, and a force acts to return the rotating sleeve 3 to the original position. The function of the air damper prevents the axial displacement of the rotary sleeve 3 and allows the rotary polygon mirror 1 to rotate stably.
【0023】固定軸2の外周面には、回転スリーブ3と
の間に形成される空気膜の動圧を安定させるための9個
の直線状の動圧発生溝である直線溝21〜29が形成さ
れている。これらは、図1の(b)に示すように固定軸
2の周方向に等間隔で配設され、各直線溝21〜29
は、図2に示すように、固定軸2の円筒面を所定の幅で
軸方向に帯状に切除することによって得られた3個の単
一平面30a〜30cによって構成される。On the outer peripheral surface of the fixed shaft 2, there are nine linear grooves 21 to 29, which are nine linear dynamic pressure generating grooves for stabilizing the dynamic pressure of the air film formed between the fixed shaft 2 and the rotating sleeve 3. Is formed. These are arranged at equal intervals in the circumferential direction of the fixed shaft 2 as shown in FIG.
As shown in FIG. 2, is constituted by three single planes 30a to 30c obtained by cutting the cylindrical surface of the fixed shaft 2 in a band shape in the axial direction with a predetermined width.
【0024】なお、一般的には、固定軸2と回転スリー
ブ3は両者の摩擦やゴミ等の侵入によるかじり等を低減
するために高強度窒素ケイ素(Si3 N4 )等のセラミ
ック材料で作られており、フランジ部材4はアルミニウ
ムや黄銅等の金属製で焼きばめによって回転スリーブ3
に固着され、ロータマグネット5の端面は、フランジ部
材4のフランジ部の下面に当接され、フランジ部材4の
筒状部分の外周面とロータマグネット5の内周面の間に
介在する接着剤によってフランジ部材4に接着されてい
る。In general, the fixed shaft 2 and the rotary sleeve 3 are made of a ceramic material such as high-strength silicon nitride (Si 3 N 4 ) in order to reduce galling due to friction between the two and intrusion of dust and the like. The flange member 4 is made of a metal such as aluminum or brass, and the rotating sleeve 3 is formed by shrink fitting.
The end face of the rotor magnet 5 is abutted against the lower surface of the flange portion of the flange member 4, and an adhesive is interposed between the outer peripheral surface of the cylindrical portion of the flange member 4 and the inner peripheral surface of the rotor magnet 5. It is adhered to the flange member 4.
【0025】また、ふた部材10は、アルミニウム、ス
テンレス等の金属や樹脂によって作られており、接着等
の公知の方法で回転スリーブ3の上端に固着される。The lid member 10 is made of a metal such as aluminum or stainless steel or resin, and is fixed to the upper end of the rotary sleeve 3 by a known method such as bonding.
【0026】固定軸2は上記のようにセラミック材料で
作られており、従って、加工性が低く、その外周面にヘ
リングボーン溝等の複雑な動圧発生溝を加工するのは難
しいが、直線溝21〜29は、固定軸2の円筒面を単に
軸方向に帯状に切除するだけで得られるため、ヘリング
ボーン溝等のように加工コストが著しく上昇するおそれ
はない。The fixed shaft 2 is made of a ceramic material as described above. Therefore, the workability is low and it is difficult to machine a complicated dynamic pressure generating groove such as a herringbone groove on the outer peripheral surface thereof. Since the grooves 21 to 29 are obtained by simply cutting the cylindrical surface of the fixed shaft 2 in a band shape in the axial direction, there is no possibility that the processing cost is significantly increased unlike a herringbone groove or the like.
【0027】本実施例は、加工が簡単な直線溝21〜2
9を固定軸2の外周面に9個配設することで、固定軸2
の形状精度(真円度等)に多少のバラつきがある場合で
も、空気膜の動圧分布が著しく不均一になるのを回避し
て、低い回転数で安定した軸受性能を得られるように改
良したものである。これによって、回転多面鏡の回転性
能を向上させるとともに、その軸受部を長寿命化し、走
査光学装置の低価格化と高性能化に大きく貢献できる。In this embodiment, straight grooves 21 to 2 which are easy to process are used.
9 are arranged on the outer peripheral surface of the fixed shaft 2 so that the fixed shaft 2
Even if there is some variation in the shape accuracy (roundness, etc.) of the bearing, the dynamic pressure distribution of the air film is prevented from becoming extremely uneven, and stable bearing performance is obtained at a low rotation speed. It was done. As a result, the rotating performance of the rotating polygon mirror is improved, the life of the bearing portion is extended, and the scanning optical device can greatly contribute to lower cost and higher performance.
【0028】なお、直線溝の数は、9個に限らず、9個
以上であればいくつでもよい。The number of linear grooves is not limited to nine, but may be any number as long as it is nine or more.
【0029】また、各直線溝の実質的な深さは0.02
0mm以下、その幅は、固定軸の中心角3〜20°の範
囲に相当する外周寸法であるのが望ましい。The substantial depth of each straight groove is 0.02.
0 mm or less, and the width thereof is desirably an outer peripheral dimension corresponding to a range of the central angle of the fixed shaft of 3 to 20 °.
【0030】直線溝の数が少なくとも9個必要である理
由は以下の通りである。The reason why at least nine straight grooves are required is as follows.
【0031】固定軸2の真円度が高く、固定軸2と回転
スリーブ3の間に空気膜を形成する軸受間隙の寸法が周
方向に均一である場合は、図3に示すように空気膜の動
圧分布は、各直線溝21〜22の近傍に同じ高さのピー
クP1 〜P9 を有する。このように均一な動圧分布であ
れば、固定軸2と回転スリーブ3の間を非接触に支持す
るための必要回転数は小さくてすみ、軸受性能も極めて
安定する。When the roundness of the fixed shaft 2 is high and the dimension of the bearing gap forming the air film between the fixed shaft 2 and the rotary sleeve 3 is uniform in the circumferential direction, as shown in FIG. dynamic pressure distribution has a peak P 1 to P 9 of the same height in the vicinity of the straight grooves 21 and 22. With such a uniform dynamic pressure distribution, the number of rotations required to support the fixed shaft 2 and the rotary sleeve 3 in a non-contact manner can be small, and the bearing performance is extremely stable.
【0032】ところが、図4に示すように、固定軸2の
真円度が低くてその断面が、第1の直線溝21から中心
角30°だけずれたところに長軸0−0を有する楕円形
である場合は、長軸0−0上の軸受間隙の寸法が小さく
て、長軸0−0に直交する軸上の軸受間隙の寸法が大き
いため、回転スリーブ3すなわち回転多面鏡1が時間方
向に回転するときには、第1の直線溝21に向かって時
計方向上流側から動圧のピークP7 〜P9 が徐徐に高く
なり、また、第6の直線溝26に向かって動圧のピーク
P3 〜P5 が徐徐に高くなる。このように各直線溝21
〜29の近傍の動圧のピークP1 〜P9 が徐徐に増減す
る傾向はあるものの、9個の直線溝21〜29が固定軸
2の周方向に均一に分布しているため、動圧分布の不均
一は各直線溝21〜29の近傍に分散され、しかも同一
直径上においてはほぼ均衡を保っている。その結果、直
線溝の数が例えば3個と少ない場合に比べて軸受性能は
安定し、固定軸2と回転スリーブ3の間を非接触に保つ
ための必要回転数も少なくてすむ。However, as shown in FIG. 4, the fixed shaft 2 has a low roundness and its cross section is shifted from the first straight groove 21 by a central angle of 30 °, and has an ellipse having a long axis 0-0. In the case of the shape, the size of the bearing gap on the major axis 0-0 is small and the dimension of the bearing gap on the axis orthogonal to the major axis 0-0 is large, so that the rotating sleeve 3, that is, the rotating polygon mirror 1 is time-consuming. When rotating in the direction, the dynamic pressure peaks P 7 to P 9 gradually increase from the clockwise upstream toward the first linear groove 21, and the dynamic pressure peaks toward the sixth linear groove 26. P 3 to P 5 gradually increase. Thus, each straight groove 21
Although the dynamic pressure peaks P 1 to P 9 in the vicinity of 29 to 2929 tend to gradually increase and decrease, since the nine linear grooves 21 to 29 are uniformly distributed in the circumferential direction of the fixed shaft 2, the dynamic pressure The non-uniform distribution is distributed in the vicinity of each of the straight grooves 21 to 29, and is substantially balanced on the same diameter. As a result, the bearing performance is stable as compared with the case where the number of linear grooves is small, for example, three, and the number of rotations required to keep the fixed shaft 2 and the rotating sleeve 3 in non-contact can be reduced.
【0033】直線溝の数が9個以下の例えば3個であれ
ば、図5に示すように、固定軸120の長軸0−0の近
傍に配設された第1の直線溝121の近傍に大きな動圧
のピークP11が発生し、回転方向下流側の第2の直線溝
122から第3の直線溝123にかけてこれらの近傍の
動圧のピークP12,P13が大きく変化する。このような
著しい動圧の不均一があると、軸受性能がなかなか安定
せず、固定軸120と回転スリーブ130を非接触に保
つための必要回転数は大幅に増大する。If the number of the linear grooves is nine or less, for example, three, as shown in FIG. 5, the vicinity of the first linear groove 121 disposed near the major axis 0-0 of the fixed shaft 120 will be described. large dynamic pressure peak P 11 is generated, the downstream side in the rotational direction of the second linear groove 122 from the third linear peak P 12 of these near the dynamic pressure over the groove 123, P 13 changes greatly. If there is such a significant non-uniformity of the dynamic pressure, the bearing performance is not easily stabilized, and the number of rotations required to keep the fixed shaft 120 and the rotating sleeve 130 out of contact is greatly increased.
【0034】実験によれば、固定軸の断面が楕円形状で
真円度が0.8μmであるとき、直線溝が9個設けられ
ていれば、固定軸と回転スリーブを完全に非接触に保つ
ための必要回転数は1,000rpmであるが、直線溝
の数が3個であれば、回転数が10,000rpmにな
らなければ回転スリーブを安定して非接触で回転させる
ことはできないことが判明している。According to the experiment, when the cross section of the fixed shaft is elliptical and the roundness is 0.8 μm, if the nine straight grooves are provided, the fixed shaft and the rotating sleeve are completely kept in non-contact. The required rotation speed is 1,000 rpm, but if the number of linear grooves is three, the rotation sleeve cannot be rotated stably without contact unless the rotation speed is 10,000 rpm. It is known.
【0035】なお、本実施例における空気軸受は、固定
軸のまわりを回転する回転スリーブに回転多面鏡を一体
的に結合したものであるが、回転多面鏡を回転軸に結合
し、モータハウジング等に固定されたスリーブに回転軸
を嵌合させた空気軸受でもよい。The air bearing according to the present embodiment is obtained by integrally connecting a rotary polygon mirror to a rotary sleeve that rotates around a fixed shaft. The rotary polygon mirror is connected to the rotary shaft, and a motor housing and the like are provided. An air bearing in which a rotating shaft is fitted to a sleeve fixed to the sleeve may be used.
【0036】[0036]
【発明の効果】本発明は上述のように構成されているの
で、以下に記載するような効果を奏する。Since the present invention is configured as described above, it has the following effects.
【0037】走査光学装置の回転多面鏡を回転支持する
空気軸受の加工コストを低減し、かつ、軸受性能と耐久
性を大幅に向上させることができる。このような走査光
学装置を用いることで、画像形成装置の高性能化と低価
格化を大きく促進できる。The processing cost of the air bearing that rotatably supports the rotary polygon mirror of the scanning optical device can be reduced, and the bearing performance and durability can be greatly improved. By using such a scanning optical device, it is possible to greatly promote higher performance and lower cost of the image forming apparatus.
【図1】一実施例による走査光学装置の主要部を示すも
ので、(a)はその模式断面図、(b)は固定軸のみを
別の断面で示す断面図である。FIGS. 1A and 1B show a main part of a scanning optical device according to an embodiment, wherein FIG. 1A is a schematic cross-sectional view thereof, and FIG. 1B is a cross-sectional view showing only a fixed shaft in another cross section.
【図2】図1の装置の固定軸の直線溝を説明するもの
で、(a)はその立面図、(b)は(a)の一部分を拡
大して示す拡大部分断面図である。FIGS. 2A and 2B are explanatory views of a straight groove of a fixed shaft of the apparatus shown in FIG. 1, wherein FIG. 2A is an elevation view thereof, and FIG. 2B is an enlarged partial cross-sectional view showing a part of FIG.
【図3】図1の装置の固定軸の真円度が高いときの固定
軸と回転スリーブの間の空気膜の動圧分布を説明する図
である。FIG. 3 is a diagram illustrating a dynamic pressure distribution of an air film between a fixed shaft and a rotating sleeve when the roundness of the fixed shaft of the apparatus of FIG. 1 is high.
【図4】図1の装置の固定軸の断面が楕円形状であると
きの固定軸と回転スリーブの間の空気膜の動圧分布を説
明する図である。FIG. 4 is a view for explaining a dynamic pressure distribution of an air film between the fixed shaft and the rotating sleeve when the cross section of the fixed shaft of the apparatus of FIG. 1 is elliptical.
【図5】固定軸の直線溝が3個である場合の固定軸と回
転スリーブの間の空気膜の動圧分布を説明する図であ
る。FIG. 5 is a diagram illustrating a dynamic pressure distribution of an air film between the fixed shaft and the rotating sleeve when the fixed shaft has three linear grooves.
【図6】一従来例による走査光学装置の主要部を示す模
式断面図である。FIG. 6 is a schematic sectional view showing a main part of a scanning optical device according to a conventional example.
【図7】走査光学装置全体を説明する図である。FIG. 7 is a diagram illustrating the entire scanning optical device.
1 回転多面鏡 2 固定軸 3 回転スリーブ 5 ロータマグネット 8 ステータ 21〜29 直線溝 DESCRIPTION OF SYMBOLS 1 Rotating polygon mirror 2 Fixed axis 3 Rotating sleeve 5 Rotor magnet 8 Stator 21-29 Straight groove
Claims (3)
部材とスリーブ部材からなる空気軸受と、前記軸部材ま
たはスリーブ部材と一体的に結合された回転多面鏡と、
該回転多面鏡を回転させる駆動手段を有し、前記軸部材
が、周方向に等間隔で少なくとも9個の直線状の動圧発
生溝を備えていることを特徴とする走査光学装置。An air bearing comprising a shaft member and a sleeve member which are fitted to each other and are relatively rotatable; a rotary polygon mirror integrally connected to the shaft member or the sleeve member;
A scanning optical apparatus, comprising: driving means for rotating the rotary polygon mirror; wherein the shaft member has at least nine linear dynamic pressure generating grooves at equal intervals in a circumferential direction.
る少なくとも1個の単一平面によって構成されているこ
とを特徴とする請求項1記載の走査光学装置。2. The scanning optical device according to claim 1, wherein each dynamic pressure generating groove is constituted by at least one single plane extending in the axial direction of the shaft member.
差が0.010mm以下であり、各動圧発生溝が0.0
20mm以下の深さと、前記軸部材の中心角3〜30°
以下の幅を有することを特徴とする請求項1または2記
載の走査光学装置。3. The difference between the outer diameter of the shaft member and the inner diameter of the sleeve member is 0.010 mm or less, and each dynamic pressure generating groove
A depth of 20 mm or less and a central angle of the shaft member of 3 to 30 °
3. The scanning optical device according to claim 1, wherein the scanning optical device has the following width.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8282999A JPH10111469A (en) | 1996-10-04 | 1996-10-04 | Scanning optical device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8282999A JPH10111469A (en) | 1996-10-04 | 1996-10-04 | Scanning optical device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH10111469A true JPH10111469A (en) | 1998-04-28 |
Family
ID=17659913
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP8282999A Pending JPH10111469A (en) | 1996-10-04 | 1996-10-04 | Scanning optical device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH10111469A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002295457A (en) * | 2001-03-30 | 2002-10-09 | Nippon Densan Corp | Dynamic pressure bearing device, rotational drive, recording device and manufacturing method of dynamic pressure bearing device |
-
1996
- 1996-10-04 JP JP8282999A patent/JPH10111469A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002295457A (en) * | 2001-03-30 | 2002-10-09 | Nippon Densan Corp | Dynamic pressure bearing device, rotational drive, recording device and manufacturing method of dynamic pressure bearing device |
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