JPH06265808A - Light beam scanning optical system - Google Patents
Light beam scanning optical systemInfo
- Publication number
- JPH06265808A JPH06265808A JP5034593A JP5034593A JPH06265808A JP H06265808 A JPH06265808 A JP H06265808A JP 5034593 A JP5034593 A JP 5034593A JP 5034593 A JP5034593 A JP 5034593A JP H06265808 A JPH06265808 A JP H06265808A
- Authority
- JP
- Japan
- Prior art keywords
- optical system
- light beam
- scanning optical
- beam scanning
- scanned
- 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.)
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- Mechanical Optical Scanning Systems (AREA)
- Lenses (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、例えば電子写真方式に
て画像を形成する複写機やファクシミリ、レーザ・ビー
ム・プリンタ等の画像形成装置に利用される光ビーム走
査装置に関し詳しくは光源からの光ビームを反射させて
偏向し走査を行う偏向手段と、この偏向手段の前後に配
設され、かつ偏向手段以前に収束されている光ビームを
前記偏向手段を介し被走査面上に結像される第１、第２
の結像光学系とスリットとを備えた光ビーム走査光学系
とそれを用いた画像形成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 light beam scanning device used in an image forming apparatus such as a copying machine, a facsimile, a laser beam printer, etc. for forming an image by an electrophotographic method. Deflection means for reflecting and deflecting the light beam to perform scanning, and light beams arranged before and after this deflection means and converged before the deflection means are imaged on the surface to be scanned through the deflection means. 1st, 2nd
The present invention relates to a light beam scanning optical system including the image forming optical system and a slit, and an image forming apparatus using the same.
【０００２】[0002]
【従来の技術】近年、この種の光ビーム走査光学系は、
画像信号に応じた変調を受けて光源から発せられる光ビ
ームを、回転ないし揺動する偏向手段により反射させて
偏向し感光体上を主走査する。これにより感光体は画像
露光を受け、この画像露光中主走査方向と直角な方向に
副走査移動される。2. Description of the Related Art Recently, a light beam scanning optical system of this kind has been
A light beam emitted from a light source after being modulated in accordance with an image signal is reflected and deflected by a rotating or oscillating deflecting means to perform main scanning on a photoconductor. As a result, the photoconductor is subjected to image exposure, and is sub-scanned in a direction perpendicular to the main scanning direction during this image exposure.
【０００３】これら主走査と副走査とによって、前記画
像信号に対応した静電潜像が感光体上に形成される。By these main scanning and sub-scanning, an electrostatic latent image corresponding to the image signal is formed on the photosensitive member.
【０００４】ところで前記静電潜像は高精細であり、十
分な解像度の画像露光を達成するには、結像光学系中の
レンズ外形寸法でもって光束を整形し、被走査面上での
集束ビーム形状を制御する必要がある。しかしこれには
限度がある。そこで従来、結像光学系中に前記レンズ外
形寸法に相当する光束整形装置を用いることにより、前
記集束ビーム形状の制御不足を補っている。By the way, the electrostatic latent image has a high definition, and in order to achieve image exposure with a sufficient resolution, the light beam is shaped by the outer dimension of the lens in the image forming optical system and is focused on the surface to be scanned. It is necessary to control the beam shape. But this has its limits. Therefore, conventionally, a light beam shaping device corresponding to the lens outer size is used in the imaging optical system to compensate for the insufficient control of the focused beam shape.
【０００５】これを達成するのに、結像光学系中の、特
に、平行光束部に光束整形装置が配設された光ビーム走
査光学系が実用されている。In order to achieve this, a light beam scanning optical system in which a light beam shaping device is arranged in the parallel light beam portion in the image forming optical system is practically used.
【０００６】以下に従来の光ビーム走査光学系について
説明する。図７は面倒れ補正機能付きの一般的な光ビー
ム走査光学系を示し、第１の結像光学系ａと第２の結像
光学系ｂとが偏向手段としてのポリゴンミラーｃの両側
に配され、半導体レーザｄからの横断面が楕円形の光ビ
ームｅを、主走査方向と副走査方向とで異なった屈折力
を用いた第１の結像光学系ａと第２の結像光学系ｂとに
よる２段階の結像機能により感光体ｆ上に所定の大きさ
で結像させ、第１の結像光学系ａ中の平行光束部ｇに配
設された光束整形装置ｈでもって感光体ｆ上に所定の大
きさで結像された集束ビーム形状を制御している。A conventional light beam scanning optical system will be described below. FIG. 7 shows a general light beam scanning optical system with a surface tilt correction function, in which a first image forming optical system a and a second image forming optical system b are arranged on both sides of a polygon mirror c as a deflecting means. The first imaging optical system a and the second imaging optical system that use the refraction powers of the light beam e having the elliptical cross section from the semiconductor laser d are different in the main scanning direction and the sub scanning direction. An image having a predetermined size is formed on the photoconductor f by the two-step image forming function of b and the light is shaped by the light beam shaping device h arranged in the parallel light beam portion g in the first image forming optical system a. The shape of the focused beam focused on the body f with a predetermined size is controlled.
【０００７】そして第１、第２の各結像光学系による結
像光路上の一部に面倒れ補正のためのレンズも設けられ
ている。これによってポリゴンミラーｃの回転軸の振れ
や組立精度の微少誤差が原因して、ポリゴンミラーｃの
各反射面間に生じるいわゆる面倒れの影響を防止する。A lens for correcting the surface tilt is also provided in a part of the image forming optical path by the first and second image forming optical systems. This prevents the influence of so-called surface tilt that occurs between the reflecting surfaces of the polygon mirror c due to the shake of the rotation axis of the polygon mirror c and a minute error in the assembly accuracy.
【０００８】[0008]
【発明が解決しようとする課題】ところで最近は、画像
形成を高密度な印字により高精細にすることが望まれて
いる。これを達成するには、結像光学系中の回折の影響
を受けない位置に光束を整形するスリットを配設するこ
とにより、被走査面上での集束ビーム形状を制御するこ
とが好適である。従来例における主走査方向のビーム形
状を図８（ａ）に、副走査方向のビーム形状を図８
（ｂ）に示す。By the way, recently, it has been desired to make an image formation with high definition by high-density printing. In order to achieve this, it is preferable to control the focused beam shape on the surface to be scanned by providing a slit that shapes the light beam in a position in the imaging optical system that is not affected by diffraction. . The beam shape in the main scanning direction in the conventional example is shown in FIG. 8A, and the beam shape in the sub scanning direction is shown in FIG.
It shows in (b).
【０００９】例えばスリットを結像光学系中の平行光束
部に配設させたもの（特開昭５６−１４１６６２号公
報）はスリットの取り付け・位置決めは容易であるが、
結像光学系中に平行光束部を特別に設けなくてはなら
ず、装置の簡素化・信頼性の確保が困難であり、集束ビ
ームの高精細度化に制限がある。For example, in the case where the slit is arranged in the parallel light flux portion in the image forming optical system (Japanese Patent Laid-Open No. 56-141662), the mounting and positioning of the slit is easy,
It is difficult to simplify the device and ensure reliability, and it is difficult to increase the definition of the focused beam.
【００１０】スリットを被走査面の直前に配設させたも
の（特開昭５９−２１４０１２号公報）は、スリットを
光源から最も遠くに配設されなければならず、スリット
の取り付け・位置決めが難しいという難点がある。ま
た、装置の小型化にも制限がある。In the case where the slit is arranged immediately before the surface to be scanned (Japanese Patent Laid-Open No. 59-214012), the slit must be arranged farthest from the light source, and it is difficult to attach and position the slit. There is a drawback. Further, there is a limit to downsizing of the device.
【００１１】そこで本発明は、従来知られる光ビーム走
査光学系のうち、図１に示すように光源１からの光ビー
ム２３を反射させ偏向する偏向手段４の前後に配設され
る第１、第２の結像光学系２、５が前記光ビーム２３を
偏向手段を介して被走査面６上に結像させるようにし
た、いわゆるポストオブジェクティブ型の光ビーム走査
光学系の場合、結像光学系中の光束整形装置としてスリ
ット３を選択し、特に第２の結像光学系の偏向手段側焦
点位置にスリット３を配設することにより、被走査面６
上に回折の影響をほとんど受けることなく、簡易的で、
高精度に集束ビーム形状を制御することができ、かつ高
精細度に結像させることができる点に着目し、この種の
光学系を改良することにより前記の問題を解消すると同
時に、低価格で小型かつ高解像度の光ビーム走査光学系
を提供することを目的とするものである。In view of the above, the present invention relates to the first known optical beam scanning optical system, which is disposed before and after the deflecting means 4 for reflecting and deflecting the optical beam 23 from the light source 1 as shown in FIG. In the case of a so-called post-objective type light beam scanning optical system in which the second image forming optical systems 2 and 5 form the light beam 23 on the surface 6 to be scanned through the deflecting means, the image forming optical system is used. By selecting the slit 3 as the light beam shaping device in the system, and particularly by disposing the slit 3 at the focal position on the deflecting means side of the second imaging optical system, the surface to be scanned 6 is scanned.
Simple and almost unaffected by diffraction
Focusing on the fact that the focused beam shape can be controlled with high precision and the image can be formed with high definition, and by improving this kind of optical system, the above problems can be solved and at the same time, at low cost. It is an object of the present invention to provide a compact and high resolution optical beam scanning optical system.
【００１２】[0012]
【課題を解決するための手段】上記のような課題を解決
するため、本願第１の発明は、光源からの光ビームを反
射させて偏向し走査を行う偏向手段と、この偏向手段の
前後に配設され、かつ偏向手段以前に収束されている光
ビームを前記偏向手段を介し被走査面上に結像させる第
１、第２の結像光学系とスリットとを備えた光ビーム走
査光学系であって、前記第２の結像光学系の偏向手段側
焦点位置近傍に前記スリットが配設されていることを特
徴とするものである。In order to solve the above problems, the first invention of the present application is directed to a deflecting means for reflecting and deflecting a light beam from a light source for scanning, and before and after the deflecting means. A light beam scanning optical system provided with first and second image forming optical systems and a slit for arranging a light beam, which is arranged and converged before the deflecting means, on the surface to be scanned through the deflecting means. The slit is disposed in the vicinity of the focal position of the second image-forming optical system on the deflecting unit side.
【００１３】本願第２の発明は、第１の発明においてさ
らに、第２の結像光学系が単レンズであることを特徴と
するものである。A second invention of the present application is the one according to the first invention, further characterized in that the second imaging optical system is a single lens.
【００１４】本願第３の発明は、第２の発明においてさ
らに、第２の結像光学系が、偏向手段側にトーリック
面、被走査面側に４次以上の高次展開項を有するトーリ
ック非球面または非円柱面であることを特徴とするもの
である。According to a third aspect of the present invention, in the second aspect, the second imaging optical system further includes a toric surface on the side of the deflecting means and a toric non-form having a higher-order expansion term of the fourth order or higher on the surface to be scanned. It is characterized by being a spherical surface or a non-cylindrical surface.
【００１５】本願第４の発明は、第１〜３のいずれかの
発明においてさらに偏向手段の反射面の形状が円筒面、
球面のいずれかであることを特徴とするものである。According to a fourth invention of the present application, in any one of the first to third inventions, the shape of the reflecting surface of the deflecting means is a cylindrical surface,
It is characterized by being one of spherical surfaces.
【００１６】本願第５の発明は、第１〜４のいずれかの
発明においてさらに被走査面上への結像方法がポストオ
ブジェクティブ型であることを特徴とするものである。A fifth aspect of the present invention is characterized in that, in any of the first to fourth aspects, the method of forming an image on the surface to be scanned is a post-objective type.
【００１７】本願第６の発明は、第１〜５のいずれかの
発明においてさらに第１の結像光学系が単レンズである
ことを特徴とするものである。A sixth invention of the present application is characterized in that, in any one of the first to fifth inventions, the first imaging optical system is a single lens.
【００１８】本願第７の発明は、第１〜６のいずれかの
発明においてさらに面倒れを補正する面倒れ補正手段を
備えることを特徴とするものである。A seventh invention of the present application is characterized in that the invention according to any one of the first to sixth inventions further comprises a surface tilt correcting means for correcting the surface tilt.
【００１９】本願第８の発明は、第１〜７のいずれかの
発明の光ビーム走査光学系を用いたことを特徴とする画
像形成装置である。An eighth invention of the present application is an image forming apparatus using the light beam scanning optical system according to any one of the first to seventh inventions.
【００２０】[0020]
【作用】本願第１の発明の上記構成によれば、光源から
の光ビームを反射させて偏向し走査を行う偏向手段と、
この偏向手段の前後に配設され、かつ偏向手段以前に収
束されている光ビームを前記偏向手段を介し被走査面上
に結像させる第１、第２の結像光学系とスリットとを備
えた光ビーム走査光学系であって、前記第２の結像光学
系の偏向手段側焦点位置近傍に前記スリットを配設する
ことにより、被走査面上に回折の影響をほとんど受ける
ことなく、簡易的で、高精度に集束ビーム形状を制御す
ることができ、かつ高精細度に結像させることができ
る。また結像光学系中に特別に平行光束部を設ける必要
がないため、装置の簡素化・信頼性の確保が容易であ
り、スリットが光源に近い分スリットの取り付け・位置
決めも簡易である。従って、低価格で小型かつ高解像度
の光ビーム走査光学系を容易に実現することができる。According to the above configuration of the first invention of the present application, the deflecting means for reflecting and deflecting the light beam from the light source to perform scanning,
It is provided with first and second imaging optical systems and slits arranged before and after the deflecting means and for focusing the light beams converged before the deflecting means on the surface to be scanned through the deflecting means. In the light beam scanning optical system, the slit is provided in the vicinity of the focal position on the deflecting unit side of the second imaging optical system, so that the surface to be scanned is hardly affected by diffraction and is simple. In addition, the focused beam shape can be controlled with high accuracy, and an image can be formed with high definition. In addition, since it is not necessary to provide a parallel light flux portion in the image forming optical system, it is easy to simplify the device and ensure reliability, and the slits are close to the light source, and the slits are easily attached and positioned. Therefore, it is possible to easily realize a small-sized, high-resolution optical beam scanning optical system at a low price.
【００２１】本願第２の発明の上記構成によれば、第１
の発明においてさらに、第２の結像光学系が単レンズで
あることによって、部品点数を削減し、装置を簡素化す
ることができる。According to the above configuration of the second invention of the present application,
Furthermore, in the invention of No. 2, since the second imaging optical system is a single lens, the number of parts can be reduced and the apparatus can be simplified.
【００２２】本願第３の発明の上記構成によれば、第２
の発明においてさらに、第２の結像光学系が、偏向手段
側にトーリック面、被走査面側に４次以上の高次展開項
を有するトーリック非球面または非円柱面であることに
よって、副走査方向の像面湾曲を十分に補正すると同時
に、ｆθの特性を持たせることができる。According to the above configuration of the third invention of the present application, the second invention
In the invention, the second imaging optical system is a toric aspherical surface or a non-cylindrical surface having a toric surface on the deflecting means side and a fourth-order or higher-order expansion term on the scanned surface side. The field curvature in the direction can be sufficiently corrected, and at the same time, the characteristic of fθ can be provided.
【００２３】本願第４の発明の上記構成によれば、第１
〜３のいずれかの発明においてさらに偏向手段の反射面
の形状が円筒面、球面のいずれかであることによって、
走査画角を広くすることができ、また他のレンズの作用
を偏向手段が兼ね備えるため、部品点数を削減し、装置
を簡素化すると同時に、主走査方向の像面湾曲を十分に
補正することができる。According to the above configuration of the fourth invention of the present application,
In any one of the inventions 1 to 3, the reflecting surface of the deflecting means is a cylindrical surface or a spherical surface,
Since the scanning angle of view can be widened and the deflecting means also functions as another lens, the number of parts can be reduced, the apparatus can be simplified, and at the same time, the curvature of field in the main scanning direction can be sufficiently corrected. it can.
【００２４】本願第５の発明の上記構成によれば、第１
〜４のいずれかの発明においてさらに被走査面上への結
像方法がポストオブジェクティブ型であることによっ
て、第２の結像光学系の構成が簡素になり、部品点数を
削減し、装置を簡素化することができる。According to the above configuration of the fifth invention of the present application, the first
In any one of the inventions 1 to 4, the method of forming an image on the surface to be scanned is a post-objective type, so that the configuration of the second image forming optical system is simplified, the number of parts is reduced, and the apparatus is simplified. Can be converted.
【００２５】本願第６の発明の上記構成によれば、第１
〜５のいずれかの発明においてさらに第１の結像光学系
が単レンズであることによって、部品点数を削減し、装
置を簡素化することができる。According to the above configuration of the sixth invention of the present application,
In any one of the inventions 1 to 5, since the first image forming optical system is a single lens, the number of parts can be reduced and the apparatus can be simplified.
【００２６】本願第７の発明の上記構成によれば、第１
〜６のいずれかの発明においてさらに面倒れを補正する
面倒れ補正手段を備えることによって、偏向手段の回転
軸の振れ、各反射面の傾き、組立精度等に起因した面倒
れに影響なく適正位置に十分精度よく結像することがで
きる。According to the above configuration of the seventh invention of the present application,
In any one of the inventions 1 through 6, by further providing a surface tilt correction means for correcting the surface tilt, a proper position can be obtained without affecting the surface tilt caused by the deflection of the rotation axis of the deflecting means, the inclination of each reflecting surface, the assembly accuracy and the like. Can be imaged with sufficient accuracy.
【００２７】本願第８の発明の上記構成によれば、第１
〜７のいずれかの発明の光ビーム走査光学系を用いたこ
とにより、低価格で小型かつ高解像度の画像形成装置を
容易に実現することができる。According to the above configuration of the eighth invention of the present application,
By using the light beam scanning optical system according to any one of the inventions 1 to 7, it is possible to easily realize a low-cost, small-sized, high-resolution image forming apparatus.
【００２８】[0028]
【実施例】以下本発明の一実施例のポストオブジェクテ
ィブ型走査光学系について、図面を参照しながら説明す
る。図１は本発明の一実施例におけるポストオブジェク
ティブ型走査光学系の構成を示すものである。本発明に
おいては、偏向手段としてのポリゴンミラーの反射面近
傍で副走査方向についてビームが集束されているため、
反射面の形状が円筒面、球面いずれの場合も副走査方向
の屈折力には変化が少ないので動作原理の差異はない。
本実施例は反射面が円筒面の場合である。DESCRIPTION OF THE PREFERRED EMBODIMENTS A post-objective type scanning optical system of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a post-objective type scanning optical system in an embodiment of the present invention. In the present invention, since the beam is focused in the sub-scanning direction near the reflecting surface of the polygon mirror as the deflecting means,
Whether the reflecting surface has a cylindrical surface or a spherical surface, there is little change in the refracting power in the sub-scanning direction, so there is no difference in operating principle.
In this embodiment, the reflecting surface is a cylindrical surface.
【００２９】図１において、１は半導体レーザ、２は集
束レンズ、３は被走査面上に集束されるビーム形状を制
御するスリット、４は円筒面ポリゴン、５は図３
（ａ）、（ｂ）に示した形状の補正レンズ、６は感光ド
ラム、７はポリゴンの回転中心軸である。図３（ａ）は
補正レンズ５の水平方向の形状を示した上面図、図３
（ｂ）は補正レンズ５の垂直方向の形状を示した側面図
を示すものである。図３（ａ）において、８は主走査方
向に平行で光軸を含む面内にあり主走査方向に平行な回
転対称軸、９は光軸上の点、１０は光軸上の点９を中心
とする前記主走査方向に平行な面内に存在する半径Ｒ１
の円弧を回転対称軸８を中心に回転した形状のトーリッ
ク面、１１は図３において示されたＸ−Ｙ−Ｚ座標系に
おいて面の頂点からのサグ量で示すと、数１の式In FIG. 1, 1 is a semiconductor laser, 2 is a focusing lens, 3 is a slit for controlling the shape of a beam focused on the surface to be scanned, 4 is a polygonal polygon, and 5 is a polygonal surface.
A correction lens having the shape shown in (a) and (b), 6 is a photosensitive drum, and 7 is a rotation center axis of the polygon. FIG. 3A is a top view showing the shape of the correction lens 5 in the horizontal direction.
(B) is a side view showing the vertical shape of the correction lens 5. In FIG. 3A, 8 is a rotational symmetry axis parallel to the main scanning direction and in the plane including the optical axis and parallel to the main scanning direction, 9 is a point on the optical axis, and 10 is a point 9 on the optical axis. Radius R1 existing in the plane parallel to the main scanning direction
Is a toric surface having a shape obtained by rotating the circular arc of FIG. 3 around the axis of rotational symmetry 8, and 11 is the expression of Equation 1 when it is represented by the amount of sag from the vertex of the surface in the XYZ coordinate system shown in FIG.
【００３０】[0030]
【数１】 [Equation 1]
【００３１】で示される非円柱面である。また、図３
（ｂ）において、Ｒ３はトーリック面１０の光軸上にお
ける回転対称軸８までの距離、ＴＨはレンズの中心肉厚
である。It is a non-cylindrical surface indicated by. Also, FIG.
In (b), R3 is the distance to the rotational symmetry axis 8 on the optical axis of the toric surface 10, and TH is the center thickness of the lens.
【００３２】具体的数値例を表１、表２、表３、表４に
示す。ただし、Ｙ０は有効走査幅、Ｌは円筒反射面から
感光ドラム６までの距離、Ｒは反射面の曲率、ｒはポリ
ゴンの回転中心から円筒反射面の頂点までの距離、ｄは
補正レンズ５の出射面から感光ドラム６までの距離、ｌ
は補正レンズ５の入射面からスリット３までの距離、Ｒ
１、Ｒ２、Ｒ３、Ｒ４ＴＨは図３（ａ）、（ｂ）にそれ
ぞれ示したものである。Ｋ、Ａ、Ｂ、Ｃ、Ｄは数１の式
で示した非球面係数である。Specific numerical examples are shown in Table 1, Table 2, Table 3 and Table 4. Here, Y0 is the effective scanning width, L is the distance from the cylindrical reflecting surface to the photosensitive drum 6, R is the curvature of the reflecting surface, r is the distance from the rotation center of the polygon to the apex of the cylindrical reflecting surface, and d is the correction lens 5 Distance from exit surface to photosensitive drum 6, l
Is the distance from the entrance surface of the correction lens 5 to the slit 3, R
1, R2, R3, and R4TH are shown in FIGS. 3A and 3B, respectively. K, A, B, C, and D are aspherical surface coefficients shown by the equation (1).
【００３３】[0033]
【表１】 [Table 1]
【００３４】[0034]
【表２】 [Table 2]
【００３５】[0035]
【表３】 [Table 3]
【００３６】[0036]
【表４】 [Table 4]
【００３７】以上のように構成されたポストオブジェク
ティブ型走査光学系について、以下、図４の（ａ）、
（ｂ）を用いてその動作を説明する。図４（ａ）は主走
査方向面内における光路図、図４（ｂ）は副走査方向面
内における光路図を示したものであって、半導体レーザ
１からの光束は集束レンズ２によって主走査方向・副走
査方向それぞれ異なった焦点位置をもつ集束光になり、
副走査方向については円筒面ポリゴン４の反射面近傍に
集束する。円筒面ポリゴン４は回転中心軸７を中心とし
て回転し、入射したレーザ光束を偏向し、補正レンズ５
によって感光ドラム６上に集束し走査される。その際、
補正レンズ５の副走査方向の偏向手段側焦点位置近傍に
スリットを設け、開口部４１の大きさを調整することに
より、被走査面上に集束される副走査方向のビームを所
定の大きさに制御するとともに、ビームの形状の乱れを
補正する。また、補正レンズ５は偏向点と感光ドラム６
上の被走査面とを、副走査方向で幾何光学的に共役にな
るように配置され、円筒面ポリゴン４の面倒れを補正す
るとともに、副走査方向の屈折力が主走査方向において
中心部から周辺部に行くに従って小さくなることで副走
査方向の像面湾曲を補正している。さらに、出射面を４
次以上の高次展開項を有する非円柱面にすることで、被
走査面上における主走査方向の結像位置にｆθの特性を
持たせている。The post-objective type scanning optical system configured as described above will be described below with reference to FIG.
The operation will be described with reference to FIG. 4A is an optical path diagram in the plane in the main scanning direction, and FIG. 4B is an optical path diagram in the plane in the sub-scanning direction. The light flux from the semiconductor laser 1 is main-scanned by the focusing lens 2. Focused light with different focus positions in each direction and sub-scanning direction,
In the sub-scanning direction, the light is focused near the reflecting surface of the cylindrical surface polygon 4. The cylindrical surface polygon 4 rotates about a rotation center axis 7 and deflects the incident laser beam, and the correction lens 5
The light is focused on the photosensitive drum 6 and scanned. that time,
A slit is provided in the vicinity of the focal position of the correction lens 5 in the sub-scanning direction on the deflecting unit side, and the size of the opening 41 is adjusted to make the beam in the sub-scanning direction focused on the surface to be scanned a predetermined size. It controls and corrects the disturbance of the beam shape. Further, the correction lens 5 has a deflection point and the photosensitive drum 6
The upper surface to be scanned is arranged so as to be geometrically and optically conjugate with each other in the sub-scanning direction, the surface tilt of the cylindrical surface polygon 4 is corrected, and the refracting power in the sub-scanning direction from the center part in the main scanning direction. The curvature of field in the sub-scanning direction is corrected by decreasing as it goes to the peripheral portion. In addition, the exit surface is 4
By using a non-cylindrical surface having a higher-order expansion term of the second order or higher, the image forming position in the main scanning direction on the surface to be scanned has the characteristic of fθ.
【００３８】本実施例におけるスリットの構成図を図５
に、主走査方向のビーム形状を図６（ａ）に、副走査方
向のビーム形状を図６（ｂ）に示した。FIG. 5 is a block diagram of the slit in this embodiment.
FIG. 6A shows the beam shape in the main scanning direction, and FIG. 6B shows the beam shape in the sub-scanning direction.
【００３９】以上のように本実施例によれば、補正レン
ズ５の副走査方向の偏向手段側焦点位置近傍にスリット
を配設し、開口部の大きさの調整により、被走査面上に
集束される副走査方向のビームの大きさを制御するとと
もに、ビーム形状の乱れを補正することができる。な
お、図２は上記実施例の走査光学系を画像形成装置に用
いた場合の構成を示すものである。図２において、３１
は感光ドラム、３２は上記実施例の走査光学系、３３は
一次帯電器、３４は現像器、３５は転写帯電器、３６は
クリーナー、３７は前露光ランプ、３８は定着装置、３
９は給紙カセットである。As described above, according to this embodiment, a slit is provided near the focal position of the correcting lens 5 in the sub-scanning direction on the deflecting means side, and the size of the opening is adjusted to focus the light on the surface to be scanned. The size of the beam in the sub-scanning direction that is generated can be controlled, and the disturbance of the beam shape can be corrected. Note that FIG. 2 shows a configuration when the scanning optical system of the above-described embodiment is used in an image forming apparatus. In FIG. 2, 31
Is a photosensitive drum, 32 is the scanning optical system of the above embodiment, 33 is a primary charger, 34 is a developing device, 35 is a transfer charger, 36 is a cleaner, 37 is a pre-exposure lamp, 38 is a fixing device, 3
9 is a paper feed cassette.
【００４０】また本発明はポストオブジェクティブ型走
査光学系のみならずプレオブジェクティブ型走査光学系
にも用いることができ、一方その効果は副走査方向に限
らず主走査方向にも十分適用することができる。The present invention can be applied not only to the post-objective type scanning optical system but also to the pre-objective type scanning optical system, while the effect can be applied not only to the sub-scanning direction but also to the main-scanning direction. .
【００４１】なお、図１の実施例では、第１、第２の結
像光学系２、５が各々単レンズであるが、少なくとも一
方が複数のレンズから構成されていてもよく、さらに偏
向手段４の反射面形状が円筒面であるが球面でも差し支
えない。In the embodiment of FIG. 1, each of the first and second image forming optical systems 2 and 5 is a single lens, but at least one may be composed of a plurality of lenses, and the deflecting means is further included. Although the reflecting surface of No. 4 is a cylindrical surface, it may be a spherical surface.
【００４２】[0042]
【発明の効果】本発明は上記実施例から明らかなように
以下に示す効果を有する。The present invention has the following effects, as is apparent from the above-mentioned embodiments.
【００４３】本願第１の発明によれば、光源からの光ビ
ームを反射させて偏向し走査を行う偏向手段と、この偏
向手段の前後に配設され、かつ偏向手段以前に収束され
ている光ビームを前記偏向手段を介し被走査面上に結像
させる第１、第２の結像光学系とスリットとを備えた光
ビーム走査光学系であって、前記第２の結像光学系の偏
向手段側焦点位置近傍に前記スリットを配設することに
より、被走査面上に回折の影響をほとんど受けることな
く、簡易的で、高精度に集束ビーム形状を制御すること
ができ、かつ高精細度に結像させることができる。また
結像光学系中に特別に平行光束部を設ける必要がないた
め、装置の簡素化・信頼性の確保が容易であり、スリッ
トが光源に近い分スリットの取り付け・位置決めも簡易
である。従って、低価格で小型かつ高解像度の光ビーム
走査光学系を容易に実現することができる。According to the first invention of the present application, the deflecting means for reflecting and deflecting the light beam from the light source for scanning and the light arranged before and after the deflecting means and converged before the deflecting means. A light beam scanning optical system having first and second imaging optical systems for forming an image of a beam on a surface to be scanned through the deflecting means and a slit, the deflection of the second imaging optical system. By arranging the slit in the vicinity of the focal point on the device side, the focused beam shape can be controlled with high precision and with little influence of diffraction on the surface to be scanned, and with high precision. Can be imaged on. In addition, since it is not necessary to provide a parallel light flux portion in the image forming optical system, it is easy to simplify the device and ensure reliability, and the slits are close to the light source, and the slits are easily attached and positioned. Therefore, it is possible to easily realize a small-sized, high-resolution optical beam scanning optical system at a low price.
【００４４】本願第２の発明によれば、第１の発明にお
いてさらに、第２の結像光学系が単レンズであることに
よって、部品点数を削減し、装置を簡素化することがで
きるので、装置の組立・調整の簡素化、高信頼性の確
保、小型化、低価格化を容易に実現することができる。According to the second invention of the present application, since the second imaging optical system is a single lens in the first invention, the number of parts can be reduced and the apparatus can be simplified. It is possible to easily realize simplification of assembly and adjustment of the device, ensuring high reliability, downsizing, and cost reduction.
【００４５】本願第３の発明によれば、第２の発明にお
いてさらに、第２の結像光学系が、偏向手段側にトーリ
ック面、被走査面側に４次以上の高次展開項を有するト
ーリック非球面または非円柱面であることによって、副
走査方向の像面湾曲を十分に補正することができるの
で、副走査方向の集束ビームを十分に均一化した高解像
度化を容易に実現することができると同時に、ｆθの特
性をも容易に実現することができる。According to the third invention of the present application, in the second invention, the second imaging optical system further has a toric surface on the deflecting means side and a higher-order expansion term of the fourth order or more on the scanned surface side. Since the toric aspherical surface or the non-cylindrical surface can sufficiently correct the field curvature in the sub-scanning direction, it is possible to easily realize a high resolution in which the focused beam in the sub-scanning direction is sufficiently uniformized. At the same time, the characteristic of fθ can be easily realized.
【００４６】本願第４の発明によれば、第１〜３のいず
れかの発明においてさらに偏向手段の反射面の形状が円
筒面、球面のいずれかであることによって、走査画角を
広くすることができ、また他のレンズの作用を偏向手段
が兼ね備えるため、部品点数を削減し、装置を簡素化す
ると同時に、主走査方向の像面湾曲を十分に補正するこ
とができるので、主走査方向の集束ビームを十分に均一
化した高解像度化と装置の組立・調整の簡素化、高信頼
性の確保、小型化、低価格化を容易に実現することがで
きる。According to the fourth invention of the present application, in any one of the first to third inventions, the shape of the reflecting surface of the deflecting means is either a cylindrical surface or a spherical surface, so that the scanning angle of view can be widened. In addition, since the deflecting means also functions as another lens, the number of parts can be reduced, the apparatus can be simplified, and at the same time, the field curvature in the main scanning direction can be sufficiently corrected. It is possible to easily realize high resolution with a sufficiently uniform focused beam, simplification of assembly and adjustment of the device, high reliability, downsizing, and cost reduction.
【００４７】本願第５の発明によれば、第１〜４のいず
れかの発明においてさらに被走査面上への結像方法がポ
ストオブジェクティブ型であることによって、第２の結
像光学系の構成が簡素になり、部品点数を削減し、装置
を簡素化することができるので、装置の組立・調整の簡
素化、高信頼性の確保、小型化、低価格化を容易に実現
することができる。According to the fifth invention of the present application, in the invention of any one of the first to fourth inventions, the image forming method on the surface to be scanned is of the post-objective type. Since it can be simplified, the number of parts can be reduced, and the device can be simplified, so that the assembly and adjustment of the device can be simplified, high reliability can be secured, downsizing and cost reduction can be easily realized. .
【００４８】本願第６の発明によれば、第１〜５のいず
れかの発明においてさらに第１の結像光学系が単レンズ
であることによって、部品点数を削減し、装置を簡素化
することができるので、装置の組立・調整の簡素化、高
信頼性の確保、小型化、低価格化を容易に実現すること
ができる。According to the sixth invention of the present application, in any one of the first to fifth inventions, the first imaging optical system is a single lens, so that the number of parts is reduced and the apparatus is simplified. As a result, it is possible to easily realize simplification of assembly and adjustment of the device, ensuring high reliability, downsizing, and cost reduction.
【００４９】本願第７の発明によれば、第１〜６のいず
れかの発明においてさらに面倒れを補正する面倒れ補正
手段を備えることによって、偏向手段の回転軸の振れ、
各反射面の傾き、組立精度等に起因した面倒れに影響な
く適正位置に十分精度よく結像することができるので、
高解像度化、走査特性の高精細度化と同時に、装置の組
立・調整の簡素化、高信頼性の確保を容易に実現するこ
とができる。According to the seventh invention of the present application, in any one of the first to sixth inventions, by further comprising a surface tilt correcting means for correcting the surface tilt, a deflection of the rotating shaft of the deflecting means,
Since it is possible to form an image at an appropriate position with sufficient accuracy without affecting the surface tilt caused by the inclination of each reflecting surface, the assembly accuracy, etc.
It is possible to easily realize high resolution, high definition of scanning characteristics, simplification of assembly and adjustment of the apparatus, and high reliability.
【００５０】本願第８の発明によれば、第１〜７のいず
れかの発明の光ビーム走査光学系を用いたことにより、
低価格で小型かつ高解像度の画像形成装置を容易に実現
することができる。According to the eighth invention of the present application, by using the light beam scanning optical system according to any one of the first to seventh inventions,
It is possible to easily realize a low-cost, small-sized, high-resolution image forming apparatus.
【図１】本発明の一実施例におけるポストオブジェクテ
ィブ型走査光学系の構成図FIG. 1 is a configuration diagram of a post-objective scanning optical system according to an embodiment of the present invention.
【図２】本発明の一実施例の走査光学系を用いた画像形
成装置の構成図FIG. 2 is a configuration diagram of an image forming apparatus using a scanning optical system according to an embodiment of the present invention.
【図３】本発明の一実施例における補正レンズの形状を
示す構成図FIG. 3 is a configuration diagram showing the shape of a correction lens in one embodiment of the present invention.
【図４】本発明の一実施例における光束の様子を示す模
式図FIG. 4 is a schematic diagram showing a state of a light beam according to an embodiment of the present invention.
【図５】本発明の一実施例におけるスリットの形状を示
す構成図FIG. 5 is a configuration diagram showing a shape of a slit in one embodiment of the present invention.
【図６】本発明の一実施例の走査光学系における集束ビ
ーム形状を示す説明図FIG. 6 is an explanatory diagram showing a focused beam shape in the scanning optical system according to the embodiment of the present invention.
【図７】従来例のポストオブジェクティブ型走査光学系
の構成図FIG. 7 is a block diagram of a conventional post-objective scanning optical system.
【図８】図７に示す従来例の走査光学系における集束ビ
ーム形状を示す説明図8 is an explanatory view showing a focused beam shape in the scanning optical system of the conventional example shown in FIG.
１ 半導体レーザ ２ 集束レンズ ３ スリット ４ 円筒面ポリゴン ５ 補正レンズ ６ 感光ドラム ７ 回転中心軸 ３２ 走査光学系 ３３ 一次帯電器 ３４ 現像器 ３５ 転写帯電器 ３６ クリーナー ３７ 前露光ランプ ３８ 定着装置 ３９ 給紙カセット 1 Semiconductor Laser 2 Focusing Lens 3 Slit 4 Cylindrical Surface Polygon 5 Correction Lens 6 Photosensitive Drum 7 Rotation Center Axis 32 Scanning Optical System 33 Primary Charger 34 Developer 35 Transfer Charger 36 Cleaner 37 Pre-exposure Lamp 38 Fixing Device 39 Paper Cassette
Claims (8)
査を行う偏向手段と、この偏向手段の前後に配設され、
かつ偏向手段以前に収束されている光ビームを前記偏向
手段を介し被走査面上に結像させる第１、第２の結像光
学系とスリットとを備えた光ビーム走査光学系であっ
て、前記第２の結像光学系の偏向手段側焦点位置近傍に
前記スリットが配設されていることを特徴とする光ビー
ム走査光学系。1. A deflection means for reflecting and deflecting a light beam from a light source for scanning, and a deflection means arranged before and after the deflection means.
A light beam scanning optical system including first and second image forming optical systems for forming an image of a light beam converged before the deflecting means on the surface to be scanned through the deflecting means, and a slit, The light beam scanning optical system, wherein the slit is disposed in the vicinity of a focal position on the deflecting means side of the second imaging optical system.
求項１記載の光ビーム走査光学系。2. The light beam scanning optical system according to claim 1, wherein the second imaging optical system is a single lens.
ーリック面、被走査面側に４次以上の高次展開項を有す
るトーリック非球面または非円柱面である請求項２記載
の光ビーム走査光学系。3. The second imaging optical system is a toric aspherical surface or a non-cylindrical surface having a toric surface on the deflecting means side and a fourth-order or higher-order expansion term on the scanned surface side. Optical beam scanning optical system.
面のいずれかである請求項１〜３のいずれかに記載の光
ビーム走査光学系。4. The light beam scanning optical system according to claim 1, wherein the shape of the reflecting surface of the deflecting means is either a cylindrical surface or a spherical surface.
クティブ型である請求項１〜４のいずれかに記載の光ビ
ーム走査光学系。5. The light beam scanning optical system according to claim 1, wherein a method of forming an image on a surface to be scanned is a post-objective type.
求項１〜５のいずれかに記載の光ビーム走査光学系。6. The light beam scanning optical system according to claim 1, wherein the first imaging optical system is a single lens.
請求項１〜６のいずれかに記載の光ビーム走査光学系。7. The light beam scanning optical system according to claim 1, further comprising surface tilt correction means for correcting the surface tilt.
走査光学系を用いた画像形成装置。8. An image forming apparatus using the light beam scanning optical system according to claim 1.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5034593A JPH06265808A (en) | 1993-03-11 | 1993-03-11 | Light beam scanning optical system |
| US08/207,690 US5652611A (en) | 1993-03-11 | 1994-03-09 | Optical scanning system and image forming apparatus employing same for electrophoto graphically forming images |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5034593A JPH06265808A (en) | 1993-03-11 | 1993-03-11 | Light beam scanning optical system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06265808A true JPH06265808A (en) | 1994-09-22 |
Family
ID=12856332
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5034593A Pending JPH06265808A (en) | 1993-03-11 | 1993-03-11 | Light beam scanning optical system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06265808A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7754064B2 (en) | 2006-09-29 | 2010-07-13 | Eltron Research & Development | Methods and apparatus for the on-site production of hydrogen peroxide |
-
1993
- 1993-03-11 JP JP5034593A patent/JPH06265808A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7754064B2 (en) | 2006-09-29 | 2010-07-13 | Eltron Research & Development | Methods and apparatus for the on-site production of hydrogen peroxide |
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