JP2817454B2 - Scanning optical device - Google Patents

Scanning optical device

Info

Publication number
JP2817454B2
JP2817454B2 JP3170704A JP17070491A JP2817454B2 JP 2817454 B2 JP2817454 B2 JP 2817454B2 JP 3170704 A JP3170704 A JP 3170704A JP 17070491 A JP17070491 A JP 17070491A JP 2817454 B2 JP2817454 B2 JP 2817454B2
Authority
JP
Japan
Prior art keywords
scanning direction
light beam
optical system
optical
sub
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.)
Expired - Lifetime
Application number
JP3170704A
Other languages
Japanese (ja)
Other versions
JPH04367816A (en
Inventor
博 齋藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP3170704A priority Critical patent/JP2817454B2/en
Publication of JPH04367816A publication Critical patent/JPH04367816A/en
Application granted granted Critical
Publication of JP2817454B2 publication Critical patent/JP2817454B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は走査光学装置に関し、特
に感光体や静電記録体等の像担持体である被走査面上を
光変調された光束で走査することにより画像形成するよ
うにした例えば電子写真プロセスを有するレーザービー
ムプリンタやカラーレーザービームプリンター、マルチ
カラーレーザービームプリンター等の装置に好適な走査
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 apparatus, and more particularly, to an apparatus for forming an image by scanning a surface to be scanned, which is an image carrier such as a photoreceptor or an electrostatic recording medium, with a light-modulated beam. For example, the present invention relates to a scanning optical device suitable for a device such as a laser beam printer, a color laser beam printer, and a multi-color laser beam printer having an electrophotographic process.

【0002】[0002]

【従来の技術】従来、この種の走査光学装置において
は、例えば特公昭62−36210号等に記載されてい
るように光源手段から光変調された光束を光偏向器とし
ての回転多面鏡の反射面で偏向反射させた後、走査レン
ズ系を介して被走査面上に導光して光走査している。こ
のときの回転多面鏡の各反射面が回転軸に対して平行で
なく傾いた角度誤差(所謂面倒れ)があると被走査面上
の光束の走査位置が変位して最終的な画像出力に悪影響
を与える。
2. Description of the Related Art Conventionally, in a scanning optical apparatus of this kind, a light beam modulated by a light source means is reflected by a rotary polygon mirror as an optical deflector as described in Japanese Patent Publication No. 62-36210. After the light is deflected and reflected by the surface, the light is guided onto the surface to be scanned via the scanning lens system to perform optical scanning. At this time, if each reflecting surface of the rotary polygon mirror is not parallel to the rotation axis and has an angle error (so-called tilting), the scanning position of the light beam on the surface to be scanned is displaced, and the final image output is obtained. Has a negative effect.

【0003】そこで同公報ではこのときの面倒れによる
悪影響を除去する為に、走査レンズ系にトーリックレン
ズを用いて回転多面鏡の反射面と被走査面(被照射体
面)とを光学的な共役関係に置くことを提案している。
In this publication, in order to eliminate the adverse effect of the surface tilt at this time, a toric lens is used for the scanning lens system to optically conjugate the reflection surface of the rotary polygon mirror and the surface to be scanned (the surface to be irradiated). Suggest to put in a relationship.

【0004】[0004]

【発明が解決しようとする課題】一般に回転多面鏡の反
射面の面倒れを良好に補正する為には走査レンズ系を用
いて回転多面鏡の反射点と被走査面との光学的共役関係
を高精度に維持することが必要となってくる。
Generally, in order to satisfactorily correct the tilt of the reflecting surface of the rotating polygon mirror, the optical conjugate relationship between the reflection point of the rotating polygon mirror and the surface to be scanned is determined by using a scanning lens system. It is necessary to maintain high accuracy.

【0005】この為従来は、光源手段から出射される光
ビームが精度よく、回転多面鏡の基準位置に入射する様
に光源手段から回転多面鏡に至る光路を調整することが
できる調整手段を設けたり、又個々の部品の精度を上げ
たり、また、経時的変化に強い構造にして行っていた。
この為装置全体が複雑化及び大型化してくる傾向があっ
た。
For this reason, conventionally, there has been provided adjusting means which can adjust the optical path from the light source means to the rotary polygon mirror so that the light beam emitted from the light source means is incident on the reference position of the rotary polygon mirror with high accuracy. In addition, the accuracy of individual parts has been increased, and a structure that is resistant to changes over time has been used.
For this reason, the whole apparatus tends to be complicated and large.

【0006】図5は従来の光源手段とコリメーターレン
ズを含むユニット50において光源手段51から出射す
る光ビームの出射方向を調整する構造を示す概略図であ
る。
FIG. 5 is a schematic diagram showing a structure for adjusting the emission direction of a light beam emitted from a light source means 51 in a unit 50 including a conventional light source means and a collimator lens.

【0007】同図において51は半導体レーザー、Sは
その発光点である。52は半導体レーザー51の取り付
け基台、53はコリメーターレンズ、54はコリメータ
ーレンズの鏡筒、55は鏡筒を支持する為のホルダーで
ある。鏡筒54とホルダー55は同図のA方向に調整で
きる様になっており、D方向に平行光束が出射するよう
に調整した後、即ちピント調整を行った後に双方を固定
している。
In FIG. 1, reference numeral 51 denotes a semiconductor laser, and S denotes a light emitting point. 52 is a mounting base for the semiconductor laser 51, 53 is a collimator lens, 54 is a lens barrel of the collimator lens, and 55 is a holder for supporting the lens barrel. The lens barrel 54 and the holder 55 can be adjusted in the direction A in the figure, and are fixed after adjusting so that a parallel light beam is emitted in the direction D, that is, after performing focus adjustment.

【0008】又、図5の全体のユニット50は回転多面
鏡に対して位置出しができる様に基準面Eに対して取り
付く構造になっている。ここで基準面Eに対してコリメ
ーターレンズ54から射出する平行光束が常に一定方向
へ出射すれば良いが、半導体レーザー51の取付け基準
に対して、発光点Sは製造的に例えば30μm〜100
μmの誤差を有してくる。
The entire unit 50 shown in FIG. 5 has a structure to be attached to the reference plane E so that the unit can be positioned with respect to the rotary polygon mirror. Here, the collimated light beam emitted from the collimator lens 54 with respect to the reference plane E may be always emitted in a fixed direction.
It has an error of μm.

【0009】又、コリメーターレンズ53や鏡筒54に
もカン合のガタがあり、コリメーターレンズ53に対す
る発光点Sの位置精度は通常70μm程度ある。
Further, the collimator lens 53 and the lens barrel 54 also have loose play, and the positional accuracy of the light emitting point S with respect to the collimator lens 53 is usually about 70 μm.

【0010】今、仮りにコリメーターレンズ53の焦点
距離を10mmとして、発光点Sとコリメーターレンズ
53の光軸誤差(光軸と直交する誤差)を70μmとす
ると、絞り53aより出射する光束の傾きは24.1´
となる。又、絞り53aより回転多面鏡の反射点までの
距離を70mmとすると、反射点でのずれは0.49m
mとなる。例えば特公昭62−36210号公報で提案
している走査光学装置における面倒れの補正系では回転
多面鏡の反射点が基準値よりずれると、共役関係がくず
れてきて面倒れ補正の効果が減少したり、被走査面上に
おいて像面湾曲等の収差の変化が増大してくる。
If the focal length of the collimator lens 53 is assumed to be 10 mm and the optical axis error (error perpendicular to the optical axis) between the light emitting point S and the collimator lens 53 is assumed to be 70 μm, the light flux emitted from the stop 53a The slope is 24.1 '
Becomes If the distance from the stop 53a to the reflection point of the rotary polygon mirror is 70 mm, the deviation at the reflection point is 0.49 m.
m. For example, in the surface tilt correction system in the scanning optical device proposed in Japanese Patent Publication No. 62-36210, if the reflection point of the rotary polygon mirror deviates from a reference value, the conjugate relationship is lost and the effect of the surface tilt correction decreases. And the change of aberration such as field curvature on the scanned surface increases.

【0011】図5において基台52とホルダー55をB
方向及びC方向(B方向と直交する方向)の2次元方向
に調整する事によって基準面Eに対してD方向に出射す
る光ビームの出射方向を一定にしている。
In FIG. 5, the base 52 and the holder 55 are
The emission direction of the light beam emitted in the direction D with respect to the reference plane E is made constant by adjusting the two-dimensional directions of the direction and the direction C (the direction orthogonal to the direction B).

【0012】しかしながらこの方法は、基台52とホル
ダー55の微妙な調整を必要とし、又基台52とホルダ
ー55はそれぞれ剛性の高い材料で作る必要がある為、
構成が複雑化してくるといった問題点があった。
However, this method requires fine adjustment of the base 52 and the holder 55, and the base 52 and the holder 55 need to be made of a material having high rigidity.
There was a problem that the configuration became complicated.

【0013】本発明は光源手段からの光束を平行光束と
する第1光学系の屈折力や該第1光学系からの光束の径
を調整する絞りの位置及び絞りの開口形状を適切に設定
することにより、調整手段を用いずに又は簡易な調整手
段により光源手段からの光束を回転多面鏡の反射面の所
定位置に高精度に集光させることができ、回転多面鏡の
面倒れを良好に補正し、高精度な光走査を可能とした走
査光学装置の提供を目的とする。
According to the present invention, the position of the stop for adjusting the refractive power of the first optical system that converts the light beam from the light source means into a parallel light beam, the diameter of the light beam from the first optical system, and the aperture shape of the stop are appropriately set. Thereby, the light beam from the light source means can be condensed at a predetermined position on the reflection surface of the rotating polygon mirror with high accuracy without using the adjusting means or with a simple adjusting means, and the tilting of the rotating polygon mirror is favorably reduced. It is an object of the present invention to provide a scanning optical device capable of correcting and performing high-precision optical scanning.

【0014】[0014]

【課題を解決するための手段】本発明の走査光学装置は
光源手段からの光束を第1光学系により少なくとも主走
査方向に平行光束とし、絞りと副走査方向に屈折力を有
する第2光学系とを介した後、光偏向器の偏向面に線状
に結像させ、該光偏向器で偏向させた光束を被走査面上
に導光して光走査する際、該第1光学系の主走査方向の
焦点距離をf1、該絞りから該偏向面の偏向点までの距
離をL、該絞りの主走査方向と副走査方向の開口の長さ
を各々D1,D2としたとき 1<L/f1<4 ・・・・・・・・(1) 0.16<D2/D1<0.7 ・・・(2) なる条件を満足することを特徴としている。
A scanning optical device according to the present invention uses a first optical system to convert a light beam from a light source unit into a parallel light beam at least in a main scanning direction, and a stop and a second optical system having a refractive power in a sub-scanning direction. After that, a linear image is formed on the deflection surface of the optical deflector, and when the light flux deflected by the optical deflector is guided on the surface to be scanned and optically scanned, the first optical system When the focal length in the main scanning direction is f1, the distance from the stop to the deflection point on the deflection surface is L, and the opening lengths of the stop in the main scanning direction and the sub-scanning direction are D1 and D2, respectively, 1 <L / F1 <4... (1) 0.16 <D2 / D1 <0.7 (2)

【0015】この他本発明では、前記第2光学系は副走
査方向にのみ正の屈折力を有した前記光偏向器側に凹面
を向けたメニスカス状のシリンドリカルレンズより成っ
ていることや、前記光源手段と前記第1光学系は1つの
ユニットに固設されていること、そして前記第1光学系
と前記第2光学系を1つのアナモフィック素子より構成
したこと等を特徴としている。又本発明の走査光学装置
は、光源手段からの光束をアナモフィック素子と絞りを
用いて主走査方向に平行光束とし、副走査方向に集光し
て光偏向器の偏向面に線状に結像させ、該光偏向器で偏
向させた光束を被走査面上に導光して光走査する際、該
アナモフィック素子の主走査方向の焦点距離をf1、該
絞りから該偏向面の偏向点までの距離をL、該絞りの主
走査方向と副走査方向の開口の長さを各々D1,D2と
したとき 1<L/f1<4 0.16<D2/D1<0.7 なる条件を満足することを特徴としている。
According to the present invention, the second optical system comprises a meniscus cylindrical lens having a concave surface facing the optical deflector having a positive refractive power only in the sub-scanning direction. The light source means and the first optical system are fixedly provided in one unit, and the first optical system and the second optical system are constituted by one anamorphic element. Further, the scanning optical device of the present invention converts the light beam from the light source means into a parallel light beam in the main scanning direction by using an anamorphic element and a diaphragm, condenses the light beam in the sub-scanning direction, and forms a linear image on the deflection surface of the optical deflector. When the light beam deflected by the optical deflector is guided on the surface to be scanned and optically scanned, the focal length of the anamorphic element in the main scanning direction is f1, the distance from the aperture to the deflection point of the deflection surface. When the distance is L and the lengths of the apertures in the main scanning direction and the sub-scanning direction are D1 and D2, respectively, the condition of 1 <L / f1 <4 0.16 <D2 / D1 <0.7 is satisfied. It is characterized by:

【0016】[0016]

【実施例】図1、図2は各々本発明の実施例1の主走査
断面とそれと垂直で光軸を含む副走査断面の要部概略図
である。
FIGS. 1 and 2 are schematic views of a main scanning section and a main scanning section perpendicular to the main scanning section and including an optical axis, respectively, according to a first embodiment of the present invention.

【0017】図1、図2において、1は半導体レーザー
等から成る光源部(レーザ光源)であり、該光源部1か
ら出射された光束(光ビーム)は第1光学系としての球
面系より成るコリメータレンズ2により略平行光束とさ
れ、開口絞り3によってその断面の大きさが整えられて
第2光学系としてのシリンドリカルレンズ4に入射す
る。シリンドリカルレンズ4は副走査断面に関して屈折
力を持ち主走査断面に関して屈折力を持っていない。こ
の為シリンドリカルレンズ4を通過した光束は主走査断
面では平行光束で、副走査断面ではほぼ線状に結像され
て光偏向器としての回転多面鏡5の反射面(偏向面)5
aに入射する。
1 and 2, reference numeral 1 denotes a light source unit (laser light source) composed of a semiconductor laser or the like, and a light beam (light beam) emitted from the light source unit 1 is formed of a spherical system as a first optical system. The collimator lens 2 converts the light into a substantially parallel light beam, the cross-sectional size of which is adjusted by the aperture stop 3, and then enters the cylindrical lens 4 as the second optical system. The cylindrical lens 4 has a refractive power with respect to the sub-scanning section and has no refractive power with respect to the main scanning section. For this reason, the light beam that has passed through the cylindrical lens 4 is a parallel light beam in the main scanning section, and is formed into a substantially linear image in the sub-scanning section, and the reflection surface (deflection surface) 5 of the rotary polygon mirror 5 as an optical deflector is formed.
a.

【0018】回転多面鏡5は矢印12の方向に等速で高
速回転しており、回転多面鏡5の反射面5aの点Pに入
射した該光束は反射されて主走査断面において偏向走査
され、走査レンズ系67に入射する。走査レンズ系67
は主走査断面と副走査断面において異なる屈折力を有し
たトーリック面を有するレンズを含む全体として2つの
レンズ6,7より成っている。走査レンズ系67は集光
性と主走査断面内においてはf−θ特性を有している。
The rotary polygon mirror 5 is rotating at a high speed at a constant speed in the direction of arrow 12, and the light beam incident on the point P of the reflecting surface 5a of the rotary polygon mirror 5 is reflected and deflected and scanned in the main scanning section. The light enters the scanning lens system 67. Scan lens system 67
Is composed of two lenses 6 and 7 as a whole including a lens having a toric surface having different refractive powers in the main scanning section and the sub-scanning section. The scanning lens system 67 has a light collecting property and f-θ characteristics in the main scanning section.

【0019】走査レンズ系67を通過した光束は被走査
面である感光ドラム(像担持体)8面上に結像されてそ
の面上を矢印8a方向に略等速度直線運動で光走査す
る。
The light beam that has passed through the scanning lens system 67 is imaged on the surface of a photosensitive drum (image carrier) 8, which is the surface to be scanned, and optically scans the surface in a direction of an arrow 8a with substantially constant velocity linear motion.

【0020】尚、図1、図2において点Pは回転多面鏡
5の反射面5aの反射位置(偏向位置)を示しており、
副走査断面における光束は上述した様にシリンドリカル
レンズ4を介し略この反射位置Pに集光される。
In FIGS. 1 and 2, a point P indicates a reflection position (deflection position) of the reflection surface 5a of the rotary polygon mirror 5.
The light beam in the sub-scan section is condensed at approximately this reflection position P via the cylindrical lens 4 as described above.

【0021】ここで反射位置Pと感光ドラム8は光学的
にほぼ共役な関係に設定されているので、例えば反射面
5aが副走査断面において回転軸11に対して平行でな
く倒れても(即ち面倒れがあっても)光束は感光ドラム
8上の同一走査線上に結像される。このようにして所謂
回転多面鏡5の反射面5aの面倒れ補正系を構成してい
る。
Here, since the reflection position P and the photosensitive drum 8 are set to have an optically conjugate relationship, even if the reflection surface 5a is not parallel to the rotation axis 11 in the sub-scan section, for example, it falls down (ie, The light flux is imaged on the same scanning line on the photosensitive drum 8 (even if the surface is tilted). In this manner, a so-called surface tilt correction system for the reflection surface 5a of the rotary polygon mirror 5 is configured.

【0022】本実施例における光学系において感光ドラ
ム8面上で、例えば主走査方向に80μm、副走査方向
に100μmのスポット径の光束を得る場合の条件につ
いて求めてみる。
The conditions for obtaining a light beam having a spot diameter of, for example, 80 μm in the main scanning direction and 100 μm in the sub-scanning direction on the surface of the photosensitive drum 8 in the optical system according to the present embodiment will be described.

【0023】このとき感光ドラム面8側の光ビームの有
効FナンバーFNOは、一般的なスポット径を求める簡略
式φ=kFNOλ(φ;スポット径、k;定数、FNO;有
効Fナンバー、λ;使用波長)を使って、今k=1.6
4、λ=780nmとすると、主走査方向のFナンバー
は62.5、副走査方向のFナンバーは78.2とな
る。ここで走査レンズ系67の主走査方向の焦点距離F
をF=150mm、回転多面鏡5の反射点Pと被走査面
8の走査レンズ系67による副走査方向の横倍率を−3
倍とする。このとき図3に示すように、開口絞り3の主
走査方向の開口の寸法D1は、D1=2.4mmとな
り、シリンドリカルレンズ4の副走査方向の光束による
回転多面鏡5側の有効FナンバーFNOは26.1とな
る。
At this time, the effective F number F NO of the light beam on the photosensitive drum surface 8 side is obtained by a simple formula φ = kF NO λ (φ: spot diameter, k; constant, F NO ; effective F NO ) for obtaining a general spot diameter. Number, λ; used wavelength), and now k = 1.6
4. If λ = 780 nm, the F number in the main scanning direction is 62.5, and the F number in the sub scanning direction is 78.2. Here, the focal length F of the scanning lens system 67 in the main scanning direction
Is F = 150 mm, and the lateral magnification of the reflection point P of the rotary polygon mirror 5 and the scanned surface 8 in the sub-scanning direction by the scanning lens system 67 is -3.
Double it. At this time, as shown in FIG. 3, the dimension D1 of the aperture of the aperture stop 3 in the main scanning direction is D1 = 2.4 mm, and the effective F-number F on the rotary polygon mirror 5 side due to the light beam of the cylindrical lens 4 in the sub-scanning direction. NO becomes 26.1.

【0024】ここで開口絞り3の副走査方向の開口の寸
法D2を図3の様に楕円の短方向に設定し、D2=1.
2mmとしている。この為にシリンドリカルレンズ4の
副走査方向の焦点距離f2をf2=31.3mmと、開
口絞り3の開口径φをφ=2.4の円形にした時の半分
にする事が可能となる。
Here, the dimension D2 of the aperture in the sub-scanning direction of the aperture stop 3 is set in the short direction of the ellipse as shown in FIG.
It is 2 mm. For this reason, the focal length f2 of the cylindrical lens 4 in the sub-scanning direction can be set to f2 = 31.3 mm, and the aperture diameter φ of the aperture stop 3 can be reduced to half that of a circular shape having φ = 2.4.

【0025】又、図2に示すように開口絞り3から回転
多面鏡5の反射点P(回転多面鏡5の反射面5aが走査
範囲の中心位置を走査するときの副走査断面内における
光束の反射面5a上の集光点)までの距離をLとしたと
き、シリンドリカルレンズ4を回転多面鏡5側のレンズ
面を凹面としたメニスカス形状より構成することにより
シリンドリカルレンズ4の主平面が開口絞り3側に移動
するようにして、これによりL<f2となるようにして
いる。
Also, as shown in FIG. 2, the light beam from the aperture stop 3 to the reflection point P of the rotary polygon mirror 5 (the reflection surface 5a of the rotary polygon mirror 5 scans the center position of the scanning range in the sub-scan section). Assuming that the distance to the focal point on the reflecting surface 5a is L, the main surface of the cylindrical lens 4 is an aperture stop by forming the cylindrical lens 4 in a meniscus shape having a concave lens surface on the rotating polygon mirror 5 side. 3 so that L <f2.

【0026】尚、本実施例では距離LをL=30mmと
している。又コリメータレンズ2の焦点距離f1はf1
=10mmである。
In this embodiment, the distance L is L = 30 mm. The focal length f1 of the collimator lens 2 is f1
= 10 mm.

【0027】本実施例において前述したように例えばレ
ーザ光源1の発光点Sとコリメータレンズ2との光軸ず
れが70μm程度あったとする。そうすると、開口絞り
3より射出される光束は24.1´の傾きをもち、反射
点Pで主走査方向にずれたとすると0.21mmのずれ
となり、又副走査方向のずれとすると0.22mmのず
れとなる。このように従来の配置の系に比べると、本実
施例ではずれ量を非常に小さくする事ができる為にレー
ザーユニットのレーザー光源の発光点とコリメーターレ
ンズ2との光軸の調整が不要となり、かつ経時的な変化
にも強く構成することができる。
As described above in this embodiment, it is assumed that the optical axis deviation between the light emitting point S of the laser light source 1 and the collimator lens 2 is about 70 μm, for example. Then, the light beam emitted from the aperture stop 3 has an inclination of 24.1 ', and if it is shifted in the main scanning direction at the reflection point P, it becomes 0.21 mm, and if it is shifted in the sub-scanning direction, it becomes 0.22 mm. It becomes a gap. As described above, in this embodiment, the deviation amount can be made extremely small as compared with the conventional arrangement, so that the adjustment of the light emitting point of the laser light source of the laser unit and the optical axis of the collimator lens 2 becomes unnecessary. , And can be configured to be resistant to changes over time.

【0028】特に前述の条件式(1)、(2)を満足す
るように開口絞りやコリメータレンズ等を特定すること
により組立誤差の緩和を図りつつ感光ドラム面上に良好
なるスポットの光ビームを入射させることができるよう
にしている。
In particular, by specifying an aperture stop, a collimator lens, and the like so as to satisfy the above-mentioned conditional expressions (1) and (2), a light beam of a good spot on the photosensitive drum surface can be formed while reducing an assembly error. It can be made incident.

【0029】次に前述の条件式の技術的意味について説
明する。
Next, the technical meaning of the above conditional expression will be described.

【0030】条件式(1)の上限値を超えると、主走査
方向の光ビームのずれが大きくなりすぎ、又下限値を下
回るとコリメーターレンズの焦点距離f1が長くなりす
ぎ、装置全体が大型化し、又レーザ光源のカップリング
効率が小さくなってくる。
When the value exceeds the upper limit of conditional expression (1), the deviation of the light beam in the main scanning direction becomes too large. When the value falls below the lower limit, the focal length f1 of the collimator lens becomes too long, and the entire apparatus becomes large. And the coupling efficiency of the laser light source decreases.

【0031】この他、本実施例では前述したように条件
式(1)を良好に成り立たせる為にシリンドリカルレン
ズ4を回転多面鏡5側に凹面を向けたメニスカス形状に
する事により、主平面の位置を、レーザ光源側に移動さ
せている。
In addition, in the present embodiment, as described above, in order to satisfy the conditional expression (1) well, the cylindrical lens 4 is formed into a meniscus shape having a concave surface facing the rotating polygon mirror 5 so that the principal plane is formed. The position is moved to the laser light source side.

【0032】条件式(2)の上限値を越えるとシリンド
リカルレンズ4の焦点距離f2が大きくなる為に主走査
方向のずれを増す要因となり、又下限値を下回ると光学
的な回折の影響や開口絞りの加工精度が厳しくなる為
に、スポット径に悪影響を与えたり、コストアップにな
ってくるので良くない。
When the value exceeds the upper limit of conditional expression (2), the focal length f2 of the cylindrical lens 4 becomes large, which causes an increase in the shift in the main scanning direction. Since the processing accuracy of the drawing becomes severe, it adversely affects the spot diameter and increases the cost, which is not good.

【0033】図4(A)、(B)は本発明の実施例2の
レーザ光源近傍の主走査断面と副走査断面の要部概略図
である。
FIGS. 4A and 4B are schematic views of a main scanning section and a sub-scanning section near a laser light source according to a second embodiment of the present invention.

【0034】実施例1では第1光学系に球面単レンズ
(コリメータレンズ)、第2光学系に副走査方向のみに
パワーを有するシリンドリカルレンズを使った例を示し
たが、本実施例では第1光学系と第2光学系を双方の機
能を有した1つのアナモフィック素子41より構成して
いる。
In the first embodiment, an example is shown in which a spherical single lens (collimator lens) is used for the first optical system and a cylindrical lens having power only in the sub-scanning direction is used for the second optical system. The optical system and the second optical system are constituted by one anamorphic element 41 having both functions.

【0035】図4においてPは回転多面鏡における光束
の反射点を示している。図4(A)の主走査断面におい
てのアナモフィックレンズ41の焦点距離faは10m
mであり、この断面においてはレーザ光源の発光点Sよ
り発せられた光はアナモフィックレンズ41を通過し、
絞り3の開口幅D1=2.2mmを通過して反射点Pへ
平行光束で入射する。即ち主走査断面において第1光学
系の役割をもつ。
In FIG. 4, P indicates a reflection point of a light beam on the rotary polygon mirror. The focal length fa of the anamorphic lens 41 in the main scanning section in FIG.
m, light emitted from the emission point S of the laser light source passes through the anamorphic lens 41 in this section,
The light passes through the aperture width D1 of the stop 3 = 2.2 mm and enters the reflection point P as a parallel light flux. That is, it has a role of the first optical system in the main scanning section.

【0036】図4(B)の副走査断面においてアナモフ
ィックレンズ41の焦点距離fbは7.5mmであり、
発光点Sより射出された光ビームはアナモフィックレン
ズ41を通過し、絞り3の開口径D2=0.4mmを通
過する事によりこの光束幅を決められ、反射面P上へ結
像される。即ち副走査断面においては第2光学系の役割
をもつ。
In the sub-scanning section of FIG. 4B, the focal length fb of the anamorphic lens 41 is 7.5 mm.
The light beam emitted from the light emitting point S passes through the anamorphic lens 41, passes through the aperture diameter D2 of the diaphragm 3 = 0.4 mm, the width of this light beam is determined, and is imaged on the reflection surface P. That is, it has a role of the second optical system in the sub-scan section.

【0037】このように本実施例ではアナモフィックな
光学素子を使うことにより、第1光学系と第2光学系の
役割をもつものを1つの光学素子で達成している。
As described above, in this embodiment, by using an anamorphic optical element, one having the roles of the first optical system and the second optical system is achieved by one optical element.

【0038】尚、本発明は回転多面鏡の代わりに、回転
一面鏡やカルバノ鏡を用いた系においても同様に適用す
ることができる。又、開口絞りの形状は楕円の他に矩形
や菱形でも同様の効果を得る事が可能である。
The present invention can be similarly applied to a system using a rotating one-sided mirror or a carbano mirror instead of a rotating polygonal mirror. The same effect can be obtained even if the shape of the aperture stop is a rectangle or a rhombus other than an ellipse.

【0039】[0039]

【発明の効果】本発明によれば光源手段からの光束を平
行光束とする第1光学系の屈折力や該第1光学系からの
光束の径を調整する絞りの位置及び絞りの開口形状を適
切に設定することにより、調整手段を用いずに、又は簡
易な調整手段により光源手段からの光束を回転多面鏡の
反射面の所定位置に高精度に集光させることができ、回
転多面鏡の面倒れを良好に補正し、高精度な光走査を可
能とした走査光学装置を達成することができる。
According to the present invention, the position of the stop for adjusting the refractive power of the first optical system which converts the light beam from the light source means into a parallel light beam, the diameter of the light beam from the first optical system, and the aperture shape of the stop are changed. By appropriately setting, the light beam from the light source means can be precisely condensed at a predetermined position on the reflecting surface of the rotating polygon mirror without using the adjusting means or with a simple adjusting means, and It is possible to achieve a scanning optical device that can properly correct surface tilt and perform high-precision optical scanning.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明の実施例1の主走査断面内の要部概略図FIG. 1 is a schematic diagram of a main part in a main scanning section according to a first embodiment of the present invention.

【図2】本発明の実施例1の副走査断面内の要部概略図FIG. 2 is a schematic diagram of a main part in a sub-scanning cross section according to the first embodiment of the present invention.

【図3】図1の開口絞りの説明図FIG. 3 is an explanatory diagram of the aperture stop shown in FIG. 1;

【図4】本発明の実施例2の要部概略図FIG. 4 is a schematic view of a main part of a second embodiment of the present invention.

【図5】従来の走査光学装置における光源手段近傍の説
明図
FIG. 5 is an explanatory view near a light source means in a conventional scanning optical device.

【符号の説明】[Explanation of symbols]

1 レーザ光源 2 第1光学系 3 開口絞り 4 第2光学系 5 光偏向器 67 走査レンズ系 8 被走査面 P 反射点(偏向点) REFERENCE SIGNS LIST 1 laser light source 2 first optical system 3 aperture stop 4 second optical system 5 optical deflector 67 scanning lens system 8 scanned surface P reflection point (deflection point)

Claims (6)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】 光源手段からの光束を第1光学系により
少なくとも主走査方向に平行光束とし、絞りと副走査方
向に屈折力を有する第2光学系とを介した後、光偏向器
の偏向面に線状に結像させ、該光偏向器で偏向させた光
束を被走査面上に導光して光走査する際、該第1光学系
の主走査方向の焦点距離をf1、該絞りから該偏向面の
偏向点までの距離をL、該絞りの主走査方向と副走査方
向の開口の長さを各々D1,D2としたとき 1<L/f1<4 0.16<D2/D1<0.7 なる条件を満足することを特徴とする走査光学装置。
1. A light beam from a light source means is converted into a parallel light beam at least in a main scanning direction by a first optical system, and passes through a stop and a second optical system having a refractive power in a sub-scanning direction. When a light beam deflected by the optical deflector is guided on a surface to be scanned and optically scanned, the focal length of the first optical system in the main scanning direction is f1, and the stop is f1. Where L is the distance from the deflecting surface to the deflection point, and D1 and D2 are the lengths of the aperture in the main scanning direction and the sub-scanning direction, respectively. 1 <L / f1 <4 0.16 <D2 / D1 <0.7 A scanning optical device, wherein the following condition is satisfied.
【請求項2】 前記第2光学系は副走査方向にのみ正の
屈折力を有した前記光偏向器側に凹面を向けたメニスカ
ス状のシリンドリカルレンズより成っていることを特徴
とする請求項1の走査光学装置。
2. The apparatus according to claim 1, wherein the second optical system comprises a meniscus cylindrical lens having a positive refractive power only in the sub-scanning direction and having a concave surface facing the optical deflector. Scanning optics.
【請求項3】 前記光源手段と前記第1光学系は1つの
ユニットに固設されていることを特徴とする請求項1の
走査光学装置。
3. The scanning optical apparatus according to claim 1, wherein said light source means and said first optical system are fixedly provided in one unit.
【請求項4】 前記第1光学系と前記第2光学系を1つ
のアナモフィック素子より構成したことを特徴とする請
求項1の走査光学装置。
4. The scanning optical device according to claim 1, wherein said first optical system and said second optical system are constituted by one anamorphic element.
【請求項5】 前記第1光学系と第2光学系との間に前
記絞りを配置したことを特徴とする請求項1の走査光学
装置。
5. The scanning optical device according to claim 1, wherein said stop is disposed between said first optical system and said second optical system.
【請求項6】 光源手段からの光束をアナモフィック素
子と絞りを用いて主走査方向に平行光束とし、副走査方
向に集光して光偏向器の偏向面に線状に結像させ、該光
偏向器で偏向させた光束を被走査面上に導光して光走査
する際、該アナモフィック素子の主走査方向の焦点距離
をf1、該絞りから該偏向面の偏向点までの距離をL、
該絞りの主走査方向と副走査方向の開口の長さを各々D
1,D2としたとき 1<L/f1<4 0.16<D2/D1<0.7 なる条件を満足することを特徴とする走査光学装置。
6. A light beam from a light source means is converted into a parallel light beam in a main scanning direction by using an anamorphic element and a stop, and is condensed in a sub-scanning direction to form a linear image on a deflection surface of an optical deflector. When the light beam deflected by the deflector is guided on the surface to be scanned and optically scanned, the focal length of the anamorphic element in the main scanning direction is f1, the distance from the stop to the deflection point of the deflection surface is L,
The lengths of the apertures in the main scanning direction and the sub-scanning direction are each set to D.
A scanning optical device, wherein the following condition is satisfied: 1 <L / f1 <4 0.16 <D2 / D1 <0.7
JP3170704A 1991-06-14 1991-06-14 Scanning optical device Expired - Lifetime JP2817454B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3170704A JP2817454B2 (en) 1991-06-14 1991-06-14 Scanning optical device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3170704A JP2817454B2 (en) 1991-06-14 1991-06-14 Scanning optical device

Publications (2)

Publication Number Publication Date
JPH04367816A JPH04367816A (en) 1992-12-21
JP2817454B2 true JP2817454B2 (en) 1998-10-30

Family

ID=15909852

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3170704A Expired - Lifetime JP2817454B2 (en) 1991-06-14 1991-06-14 Scanning optical device

Country Status (1)

Country Link
JP (1) JP2817454B2 (en)

Also Published As

Publication number Publication date
JPH04367816A (en) 1992-12-21

Similar Documents

Publication Publication Date Title
US6940535B2 (en) Multi-beam optical scanning device, and image forming apparatus and color image forming apparatus using the same
JP3035993B2 (en) Optical scanning device
US5038156A (en) Light beam scanning optical system
JP3104618B2 (en) Optical scanning device and optical lens
JP2830670B2 (en) Optical scanning device
JP2003107382A (en) Scanning optical system
JP2001021822A (en) Optical scanning optical system and image forming device using the system
JPH07111509B2 (en) Optical scanning device
JP3323354B2 (en) Optical scanning device
JP2956169B2 (en) Scanning optical device
JP2817454B2 (en) Scanning optical device
JPH07128604A (en) Scanning optical device
JP3198750B2 (en) Optical scanning device
JP2971005B2 (en) Optical scanning device
JP2643224B2 (en) Light beam scanning optical system
JPH0618802A (en) Optical scanning device
JP2000180749A (en) Optical scanner
JP2001125033A (en) Scanning optical system and image forming device
JPH0619494B2 (en) Optical scanning device
JP2657381B2 (en) Light flux adjusting method for scanning optical device
JP2002040340A (en) Laser beam scanner
JP3132047B2 (en) Light beam scanning optical system
JP3571808B2 (en) Optical scanning optical system and laser beam printer including the same
JPH0943529A (en) Optical scanner
JP2757308B2 (en) Light beam scanning optical device

Legal Events

Date Code Title Description
FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20070821

Year of fee payment: 9

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20080821

Year of fee payment: 10

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20080821

Year of fee payment: 10

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090821

Year of fee payment: 11

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090821

Year of fee payment: 11

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100821

Year of fee payment: 12

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110821

Year of fee payment: 13

EXPY Cancellation because of completion of term
FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110821

Year of fee payment: 13