JPS63216018A - Optical scanner - Google Patents
Optical scannerInfo
- Publication number
- JPS63216018A JPS63216018A JP62051055A JP5105587A JPS63216018A JP S63216018 A JPS63216018 A JP S63216018A JP 62051055 A JP62051055 A JP 62051055A JP 5105587 A JP5105587 A JP 5105587A JP S63216018 A JPS63216018 A JP S63216018A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- scanning
- scanning direction
- optical
- imaging
- 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
- 230000003287 optical effect Effects 0.000 title claims abstract description 48
- 230000001678 irradiating effect Effects 0.000 claims abstract description 3
- 238000003384 imaging method Methods 0.000 claims description 64
- 230000004075 alteration Effects 0.000 abstract description 7
- 230000015572 biosynthetic process Effects 0.000 abstract 5
- 230000004907 flux Effects 0.000 abstract 3
- 230000000694 effects Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 235000017166 Bambusa arundinacea Nutrition 0.000 description 1
- 235000017491 Bambusa tulda Nutrition 0.000 description 1
- 241001330002 Bambuseae Species 0.000 description 1
- VCUFZILGIRCDQQ-KRWDZBQOSA-N N-[[(5S)-2-oxo-3-(2-oxo-3H-1,3-benzoxazol-6-yl)-1,3-oxazolidin-5-yl]methyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C1O[C@H](CN1C1=CC2=C(NC(O2)=O)C=C1)CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F VCUFZILGIRCDQQ-KRWDZBQOSA-N 0.000 description 1
- 235000015334 Phyllostachys viridis Nutrition 0.000 description 1
- 239000011425 bamboo Substances 0.000 description 1
- 235000020289 caffè mocha Nutrition 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
Landscapes
- Exposure Or Original Feeding In Electrophotography (AREA)
- Lenses (AREA)
- Facsimile Scanning Arrangements (AREA)
- Mechanical Optical Scanning Systems (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は１例えばレーザープリンター等に適用可能な光
走査装置に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical scanning device applicable to, for example, a laser printer.
（従来の技術）
レーザー光などの光ビームを走査して情報を記録する装
置、例えばレーザープリンターでは、一般に、結像レン
ズとしてｆＯレンズ、即ち、焦点比ｌｆと偏向角θが像
高ｙに関して正確に比例関係を保つようにした結像レン
ズが用いられている。(Prior Art) Devices that record information by scanning a light beam such as a laser beam, such as a laser printer, generally use an fO lens as an imaging lens, that is, the focal ratio lf and the deflection angle θ are accurate with respect to the image height y. An imaging lens is used that maintains a proportional relationship between
そして、光ビームを偏向する目的で回転多面鏡が用いら
れ、これにより一定時間内での走査回数の増加を図って
いる。A rotating polygon mirror is used to deflect the light beam, thereby increasing the number of scans within a certain period of time.
しかしながら、これらの装置では、回転多面鏡及びその
駆動モータの微小な加工誤差、これら光学部品の組立調
整誤差等により、ｆＯレンズを介して走査結像されるビ
ームスポットの位置が偏移し、その結果、結像面上での
ピッチむらを発生させ１画像品位を著しく低下させるこ
とになる。However, in these devices, the position of the beam spot scanned and imaged through the fO lens shifts due to minute processing errors in the rotating polygon mirror and its drive motor, assembly adjustment errors in these optical components, etc. As a result, pitch unevenness occurs on the imaging plane, significantly degrading the quality of one image.
これは主に、回転多面鏡の反射面が回転軸に対して傾い
て加工されたり、回転多面鏡の駆動モータの回転軸が傾
いていたりして所謂面倒れが発生することにより、ビー
ムの反射角０に微小な誤差へ〇が発生するためである。This is mainly caused by the reflection surface of the rotating polygon mirror being machined to be tilted with respect to the rotation axis, or the rotation axis of the drive motor of the rotating polygon mirror being tilted, resulting in so-called surface tilt. This is because a small error occurs at the angle 0.
一般に、結像面上でのビームスポットの偏移量Δｙと上
記反射角の誤差Δθとの関係は次のようになる。Generally, the relationship between the amount of deviation Δy of the beam spot on the imaging plane and the error Δθ of the reflection angle is as follows.
ΔＭ＝２・ｆ・Δθ ・・・・（１）この式（１）
で推知できるように、八〇が微小であっても、光走査装
置に結像レンズとして用いられるｆＯレンズの焦点距離
ｆが長いため、ビームスポットの偏移量Δｙは極めて大
きくなる６従って１回転多面鏡の面倒れによる不具合を
補償する必要がある。ΔM=2・f・Δθ...(1) This formula (1)
As can be inferred from the above, even if 80 is small, the focal length f of the fO lens used as an imaging lens in the optical scanning device is long, so the deviation amount Δy of the beam spot becomes extremely large6.Therefore, one rotation It is necessary to compensate for problems caused by the tilting of the polygon mirror.
いま、仮に光走査装置の分解能を１インチ当たり３００
ドツトとすれば、１インチ＝２５．４ｍｍであるから
、必要なビームスポット径は０．０８５ｍｍとなる。Now, suppose the resolution of the optical scanning device is 300 per inch.
In the case of a dot, 1 inch = 25.4 mm, so the required beam spot diameter is 0.085 mm.
ここで、ｆθレンズの焦点距離ｆを２００ｍｍ、許容偏
移量をビームスポット径の約１／４とすればΔｙ＝０．
０２２となり、上記式（１）より反射系の微小誤差ΔＯ
は、
八〇 ＝０．０２２／ （２Ｘ ２００）となり、Δθ
＝１１．３ （秒）が算出され、回転多面鏡の反射面の
傾き誤差を１１秒以内に調整することが要求されること
がわかる。しかし１機械的な工作の精度を上げてこのよ
うな微小な誤差範囲内に調整することは極めて困難であ
り、現実的ではない。Here, if the focal length f of the fθ lens is 200 mm and the allowable deviation amount is approximately 1/4 of the beam spot diameter, Δy=0.
022, and from the above formula (1), the minute error ΔO of the reflection system
is 80 = 0.022/ (2X 200), and Δθ
=11.3 (seconds) is calculated, and it can be seen that it is required to adjust the tilt error of the reflecting surface of the rotating polygon mirror within 11 seconds. However, it is extremely difficult and impractical to increase the precision of mechanical machining and adjust it within such a minute error range.
そこで、従来の光走査装置では一般に、第１１図。Therefore, in the conventional optical scanning device, the image shown in FIG. 11 is generally used.
第１２図にも示されているように、レーザー光源を含む
照射手段からのほぼ平行な光ビーム３１を第１シリンダ
ーレンズ３２により主走査方向にのみ収束させて、図示
されない回転多面鏡の反射面に同回転多面鏡の回転軸に
直交する方向の細線３３を形成させ、上記回転多面鏡に
よる反射光をｆＯレンズでなる結像レンズ３４と第２シ
リンダーレンズ３５によって走査結像面３６に収束させ
るようにすると共に、回転多面鏡の反射面と走査結像面
３６との間で共役関係が成立するように、結像レンズ３
４と合わせで上記シリンダーレンズ３５のパワーを設定
し、もって１回転状態での反射面の傾き誤差を吸収し、
ビームスポットの偏移を抑えるようになっている。As shown in FIG. 12, a substantially parallel light beam 31 from an irradiation means including a laser light source is converged only in the main scanning direction by a first cylinder lens 32, and the reflecting surface of a rotating polygon mirror (not shown) is A thin line 33 is formed in a direction perpendicular to the rotation axis of the rotary polygon mirror, and the light reflected by the rotary polygon mirror is converged onto a scanning imaging plane 36 by an imaging lens 34 made of an fO lens and a second cylinder lens 35. At the same time, the imaging lens 3
In combination with 4, the power of the cylinder lens 35 is set to absorb the tilt error of the reflective surface during one rotation,
It is designed to suppress deviation of the beam spot.
特公昭５２−２８６６６号公報記載のものはその一つで
ある。The one described in Japanese Patent Publication No. 52-28666 is one of them.
また、特開昭５９−１４７３１６号公報に記載されてい
るように、主走査方向に関してｆθレンズを構成し、副
走査方向にのみ収束作用を有し、偏向反射面と走査結像
面との間に共役関係が成立するようにパワーを設定した
特殊な形状の結像レンズ系も提案されている。Furthermore, as described in Japanese Patent Application Laid-Open No. 59-147316, an fθ lens is constructed in the main scanning direction, has a convergence effect only in the sub-scanning direction, and has a convergence effect between the deflection reflection surface and the scanning imaging surface. An imaging lens system with a special shape whose power is set so that a conjugate relationship is established has also been proposed.
さらに、特公昭５ｇ−１５７６７号公報に記載されてい
るように、光束を集束させるための光学系の主走査方向
の焦点距離よりも副走査方向の焦点距離を短＜シ、かつ
、主走査方向及び副走査方向の焦点位置を走査結像面上
で合致させることを特徴とする光走査装置が提案されて
いる。Furthermore, as described in Japanese Patent Publication No. 5g-15767, the focal length in the sub-scanning direction of the optical system for converging the light beam is shorter than the focal length in the main scanning direction, and An optical scanning device has been proposed in which the focal positions in the sub-scanning direction and the sub-scanning direction are made to coincide on the scanning imaging plane.
（発明が解決しようとする問題点）
特開昭５２−２８６６６号公報及び特開昭５９−１４７
３１６号公報記載のものは何れも偏向面上にｗｃ橡を形
成するため、
（１）偏向面の傷、汚れ等の影響を受は易い。(Problems to be solved by the invention) JP-A-52-28666 and JP-A-59-147
Since all of the devices described in Japanese Patent No. 316 form a wc layer on the deflection surface, (1) they are easily affected by scratches, dirt, etc. on the deflection surface;
（２）レザー光による偏向面の焼き付けが発生し易い。(2) Burning of the deflection surface by laser light is likely to occur.
（３）光学系の副走査方向における入射側の開口数が極
めて小さいため、レーザーエネルギーの利用効率が著し
く低下する。(3) Since the numerical aperture of the optical system on the incident side in the sub-scanning direction is extremely small, the utilization efficiency of laser energy is significantly reduced.
という問題がある。There is a problem.
また、特公昭５８−１５７６７号公報記載のものによれ
ば、主走査方向と副走査方向の焦点距離が異なるため、
走査結像面上で真円のビームを得るためには式（２）で
示されているように光学系への入射ビームを楕円形状に
する必要がある。Moreover, according to the one described in Japanese Patent Publication No. 58-15767, since the focal lengths in the main scanning direction and the sub-scanning direction are different,
In order to obtain a perfectly circular beam on the scanning imaging plane, it is necessary to make the beam incident on the optical system elliptical as shown in equation (2).
ただし、λ：波長、ｆ：焦点距離、
ｄ：入射光の径、Ｗｄ：ビームウェストの径そして、光
学系への入射ビームは式（３）で示される条件を満す必
要がある。However, λ: wavelength, f: focal length, d: diameter of incident light, Wd: diameter of beam waist, and the incident beam to the optical system must satisfy the conditions shown in equation (3).
ただし、ｆｙＣ主走査方向の焦点距ｍ。However, fyC focal length in the main scanning direction is m.
ｆｘ：副走査方向の焦点距は。fx: Focal length in the sub-scanning direction.
Ｑｙ＝主走査方向のビーム径、
Ｑｘ＝副走査方向のビーム径、
このように、上記公報記載のものによれば、走査結像面
上でのビーム形状を真円にするためには走査用レンズ系
に入射するビーム形状を楕円形にする必要があり、その
ためにコリメートレンズを含む第ルンズ系中にプリズム
又は凸シリンダーレンズと凹シリンダーレンズの組み合
わせよりなるビーム形状補正用の光学系が必要となる。Qy = Beam diameter in the main scanning direction, Qx = Beam diameter in the sub-scanning direction. Thus, according to the above publication, in order to make the beam shape on the scanning image plane a perfect circle, It is necessary to make the beam shape incident on the lens system elliptical, and for this purpose, an optical system for beam shape correction consisting of a prism or a combination of a convex cylinder lens and a concave cylinder lens is required in the first lens system including the collimating lens. Become.
このため、レンズ系のアライメントが複雑になると共に
、レンズニレメン］−が増大して大幅なコスト上昇をま
ねくことになる。For this reason, alignment of the lens system becomes complicated, and the lens diameter increases, leading to a significant increase in cost.
本発明は、かかる従来の問題点を解消するためになされ
たものであって、光偏向器に照射される光ビームをほぼ
平行光束としながら、光偏向器の所謂面倒れによる副走
査方向へのビームスポットの偏移の補正を可能にし、も
って、偏向反射面でのごみや傷、汚れ等の影響を受動ず
、偏向反射面での焼きつきのない光走査装置を提供する
ことを目的とし、また、走査結像面上での収差補正が容
易な光走査装置を提供することを目的とする。The present invention has been made to solve such conventional problems, and while the light beam irradiated to the optical deflector is made into a substantially parallel light beam, the light beam irradiated to the optical deflector is made into a substantially parallel beam, and the light beam is prevented from moving in the sub-scanning direction due to the so-called surface tilt of the optical deflector. It is an object of the present invention to provide an optical scanning device that enables correction of the deviation of a beam spot, is not affected by dust, scratches, dirt, etc. on the deflection reflection surface, and is free from burn-in on the deflection reflection surface. An object of the present invention is to provide an optical scanning device that allows easy correction of aberrations on a scanning imaging plane.
（問題点を解決するための手段）
本発明は、第１図に示されているように、光源からのビ
ーム１を所定の径のほぼ平行光束として照射する照射手
段と、この照射手段からの光束を偏向する光偏向器２と
、この光偏向器２により偏向された上記光束を結像させ
るための結像レンズ系３と、この結像レンズ系３と走査
結像面との間に配置された凸シリンダーレンズ６とを有
してなる光走査装置であって、その特徴とするところは
、上記結像レンズ系３を複数のレンズエレメントによる
ｆθレンズで構成し、このｆＯレンズの複数のレンズエ
レメントのうちの少なくとも一つの面を主走査方向に曲
率半径が無限大となる曲率無限大面とし、この曲率無限
大面に凹シリンダーレンズ面４を設け、主走査方向の焦
点位１１Ｐｏを上記走査結像面７に一致させると共に、
上記凸シリンダーレンズ６を光軸方向に移動調整して副
走査方向の焦点位置を上記走査結像面７より所定量光軸
方向へずらし、走査結像面７における副走査方向のビー
ム径を主走査方向のビームウェストと略同一にしたこと
にある。(Means for Solving the Problems) As shown in FIG. 1, the present invention includes an irradiation means for irradiating a beam 1 from a light source as a substantially parallel light beam having a predetermined diameter, and a beam 1 from this irradiation means. A light deflector 2 for deflecting a light beam, an imaging lens system 3 for forming an image of the light beam deflected by the light deflector 2, and an arrangement between the imaging lens system 3 and the scanning imaging plane. This optical scanning device has a convex cylindrical lens 6, and its features are that the imaging lens system 3 is composed of an fθ lens made up of a plurality of lens elements; At least one surface of the lens element is an infinite curvature surface whose radius of curvature is infinite in the main scanning direction, a concave cylindrical lens surface 4 is provided on this infinite curvature surface, and the focal point 11Po in the main scanning direction is set as above. While aligning with the scanning imaging plane 7,
The convex cylinder lens 6 is moved and adjusted in the optical axis direction to shift the focal position in the sub-scanning direction by a predetermined amount from the scanning imaging plane 7 in the optical axis direction, and the beam diameter in the sub-scanning direction on the scanning imaging plane 7 is adjusted as the main beam diameter. The reason is that the beam waist in the scanning direction is made approximately the same.
（作 用）
光偏向器２には所定の径のほぼ平行な光ビーム１が照射
され偏向される。結像レンズ系３を構成する複数のレン
ズエレメントによろｆθレンズは、その少なくとも一つ
のレンズエレメントが主走査方向に関しては曲率半径が
無限大であり、副走査方向に関してのみ凹のシリンダー
面４が形成され、結像レンズ系３と走査結像面７との間
に配置された凸シリンダーレンズ６との合成により副走
査方向に係る合成焦点距離が短焦点化される。(Function) A substantially parallel light beam 1 having a predetermined diameter is irradiated onto the optical deflector 2 and is deflected. Due to the plurality of lens elements constituting the imaging lens system 3, at least one lens element of the fθ lens has an infinite radius of curvature in the main scanning direction, and forms a concave cylindrical surface 4 only in the sub-scanning direction. By combining the imaging lens system 3 and the convex cylinder lens 6 disposed between the scanning imaging surface 7, the combined focal length in the sub-scanning direction is shortened.
また、主走査方向の焦点位置と副走査方向の焦点位置を
走査結像面７上で合致させるための所定の基準位置に対
し、凸シリンダーレンズ６を光軸方向に移″Ｓ調整して
副走査方向の焦点位置を走査結像面７から前後に変位さ
せることにより、レンズ系３に入射するビーム形状が真
円であるにもかかわらず、走査語ｔｉｔ面７上で略真円
に等しい所定の万解能を有するビーム径を得ることがで
きる。In addition, the convex cylinder lens 6 is moved in the optical axis direction with respect to a predetermined reference position for matching the focal position in the main scanning direction and the focal position in the sub-scanning direction on the scanning imaging plane 7, and the sub-scanning direction is adjusted. By displacing the focal point position in the scanning direction back and forth from the scanning imaging plane 7, even though the beam shape incident on the lens system 3 is a perfect circle, a predetermined beam shape that is approximately equal to a perfect circle on the scanning word tit plane 7 is formed. It is possible to obtain a beam diameter with universal resolution.
第１図、第２図はこのような作用を説明するものであっ
て、ＰＯは主走査方向の焦点位１ｉＷ、Ｐ＋は凸シリン
ダーレンズ６を前方に変位させたときの副走査方向の焦
点位置、Ｐ１′ は凸シリンダーレンズ６を後方に変位
させたときの副走査方向の焦点位置を示す。ここで十分
に補正されたｆＯレンズを用いれば、主走査方向の焦点
面上でのビーム径は前記式（２）によって得られる。こ
のとき主走力向の焦点距離ｆｙと副走査方向の焦点距ｍ
ｆｘとの関係はｆｙ）ｆｘであって、主走査方向の焦点
位置Ｐｏにおいては主走査方向のビーム径Ｗｄｙと副走
査方向のビーム径Ｗｄｘとの関係はＷｄｙ＞Ｗｄｘとな
って真円にならない。しかし、本発明では第２図に示さ
れているようにｆＯレンズ系と走査結像面７の間に配に
された凸シリンダーレンズ６を前後に所定の量だけ光軸
方向に変位させることにより、主走査方向の焦点位［Ｐ
ｏは走査結像面７から移動させることなく副走査方向の
焦点位はのみを走査結像面７から移動させることができ
、主走査方向の焦点位置Ｐａがある走査結像面７上にお
いて略真円のビームを得ることができる。FIGS. 1 and 2 explain such an effect, where PO is the focal position 1iW in the main scanning direction, and P+ is the focal position in the sub-scanning direction when the convex cylinder lens 6 is displaced forward. , P1' indicates the focal position in the sub-scanning direction when the convex cylinder lens 6 is displaced backward. If a sufficiently corrected fO lens is used here, the beam diameter on the focal plane in the main scanning direction can be obtained by the above equation (2). At this time, the focal length fy in the main scanning direction and the focal length m in the sub-scanning direction
The relationship with fx is fy)fx, and at the focus position Po in the main scanning direction, the relationship between the beam diameter Wdy in the main scanning direction and the beam diameter Wdx in the sub-scanning direction is Wdy>Wdx, and it is not a perfect circle. . However, in the present invention, as shown in FIG. 2, by displacing the convex cylinder lens 6 disposed between the fO lens system and the scanning image plane 7 by a predetermined amount back and forth in the optical axis direction, , focal position in the main scanning direction [P
o can move only the focal position in the sub-scanning direction from the scanning imaging plane 7 without moving it from the scanning imaging plane 7, and approximately on the scanning imaging plane 7 where the focal position Pa in the main scanning direction is located. A perfectly circular beam can be obtained.
ここで、主走査方向の焦点位［Ｐｏに対する副走査方向
の焦点位置Ｐ１のずれ量ΔＱは、であり、ｆｙ≠ｆｘで
あるから、
となる。いま仮りに、主走査方向の焦点距離ｆｙ＝１２
５ｍｍ、副走査方向の焦点圧はｆｘ ＝ ５０ｍｍ、λ
＝７８０ｎｎ＋とし、印字品質を３００ ＤＰＩとすれ
ば、Ｗｄキ０．０８４ｍ＋ｏφとなり、前記式（２）よ
り８年１．４７８ｍｍとなる。そして１以上の条件を基
にΔＱを求めれば、Δｎ４２．８４ｍｍとなる。従って
、上記ΔＱを得るに必要な量ΔＸだけ凸シリンダーレン
ズ６を光軸方向に前後に移動させればよいことになる。Here, the amount of deviation ΔQ of the focus position P1 in the sub-scanning direction with respect to the focus position [Po in the main-scanning direction is, and since fy≠fx, it is as follows. For now, the focal length in the main scanning direction is fy=12
5mm, focal pressure in the sub-scanning direction is fx = 50mm, λ
=780nn+, and if the print quality is 300 DPI, then Wd is 0.084m+oφ, which is 8 years and 1.478mm from the above formula (2). If ΔQ is calculated based on one or more conditions, Δn is 42.84 mm. Therefore, it is sufficient to move the convex cylinder lens 6 back and forth in the optical axis direction by the amount ΔX necessary to obtain the above-mentioned ΔQ.
（実施例）
第３図乃至第５図において、局面に多数の反射面が形成
され、かつ、回転軸を中心に駆動モータによって回転駆
動される回転多面鏡１２の上記反射面には１図示されな
い光源及び照射手段を介して所定のビーム径のほぼ平行
光束１１が照射され、この光束１１を偏向するようにな
っている。上記光束１１は周知のように記録しようとす
る情報信号に応じて変調されている。回転多面ｆｉ１２
による偏向光路上には二つのレンズエレメント１３，１
４でなるｆＯレンズが配置されている。このｆＯレンズ
は結像レンズ系を構成し、走査結像面１６上に結像させ
ろようになっている。この結像レンズ系と走査結像面１
６との間には凸シリンダーレンズ１５が第５図に破線で
示されているように所定の範囲で光軸方向に移動調整可
能に配置され、もって、副走査方向の焦点位置をＰｌと
Ｐ、′ で示されているように主走査方向の焦点位１１
Ｐｏの前後にずらすことができるようになっている。(Example) In FIGS. 3 to 5, one of the reflective surfaces of the rotating polygon mirror 12, which has a large number of reflective surfaces formed on its curved surface and is rotationally driven by a drive motor around a rotation axis, is not shown. A substantially parallel light beam 11 having a predetermined beam diameter is irradiated via a light source and an irradiation means, and this light beam 11 is deflected. As is well known, the light beam 11 is modulated in accordance with the information signal to be recorded. rotating polygon fi12
There are two lens elements 13, 1 on the optical path deflected by
4 fO lenses are arranged. This fO lens constitutes an imaging lens system and is designed to form an image on the scanning imaging plane 16. This imaging lens system and scanning imaging surface 1
6, a convex cylinder lens 15 is disposed so as to be movable and adjustable in the optical axis direction within a predetermined range as shown by the broken line in FIG. , ′, the focal position 11 in the main scanning direction
It is possible to shift it before or after Po.
上記結像レンズ系を構成するｆＯレンズの複数のレンズ
エレメントのうちの一つのエレメント１３は、その光源
側の面が球面で構成され、結像面側が主走査方向に関し
曲率半径が無限大となる無限大面となっており、他方の
レンズエレメント１４は、光源側が凹シリンダー面、結
像側が球面になっている。凸シリンダーレンズ１５は、
光源側が凸シリンダーレンズ面、結像面側が平面になっ
ている。One element 13 of the plurality of lens elements of the fO lens constituting the above-mentioned imaging lens system has a spherical surface on the light source side, and the radius of curvature of the imaging surface side in the main scanning direction is infinite. The other lens element 14 has a concave cylindrical surface on the light source side and a spherical surface on the imaging side. The convex cylinder lens 15 is
The light source side is a convex cylindrical lens surface, and the image forming surface side is a flat surface.
次に、上記の如き光学配置でなる本発明の実施例を示す
。Next, an embodiment of the present invention having the optical arrangement as described above will be described.
実施例１
ν Ｒ（主） Ｒ（副）ｄ Ｎ１
ｏｏｏｏ１３．０
２ −６３．３ −６３．３ ３．０ １．４
８２６１３ ４７８．２１ ４７８．２１ １５．
０４ ｃｌｌ）−２００，０７，２１，７８５７１
５−６７，９３−６７，９３１８２，６２６Ｃｏ
２８．６２ ６．０ １．５１１１Ｂ７
ｏｏ ｏｏ ５０ 、 ＯｆＡ ＝ ２
００．００４７Ｒ１１１１ｆＢ＝ ５０．５０４９ｎｖ
＋
但し、第１面は偏向反射面を示す。使用波長λは７８０
ｎｙｍである。また、νは面番数、ｆＡは主走査方向の
焦点距離、 ｆＢは副走査方向の焦点距離、Ｒ（主）は
主走査方向の曲率半径、Ｒ（副）は副走査方向の曲率半
径、ｄは各面間の距離、Ｎは波長７８０ ｎ ｍに対す
る屈折率を示しており、以下同様とする。凸シリンダー
レンズ１５は前述のようにΔＱ４２．８４＋ｎｎｉの範
囲で前後に移動させられるため、ｄ。Example 1 ν R (main) R (secondary) d N1
oooo13.0 2 -63.3 -63.3 3.0 1.4
82613 478.21 478.21 15.
04 cll)-200,07,21,78571
5-67, 93-67, 93182, 626Co
28.62 6.0 1.5111B7
oo oo 50 , OfA = 2
00.0047R1111fB=50.5049nv
+ However, the first surface represents a deflection reflecting surface. The wavelength used is 780
It is nym. In addition, ν is the surface number, fA is the focal length in the main scanning direction, fB is the focal length in the sub-scanning direction, R (main) is the radius of curvature in the main scanning direction, R (sub) is the radius of curvature in the sub-scanning direction, d represents the distance between each surface, and N represents the refractive index for a wavelength of 780 nm, and the same applies hereinafter. Since the convex cylinder lens 15 is moved back and forth within the range of ΔQ42.84+nni as described above, d.
は上記実施例の１８２．６２を中心として前後に移動す
る。moves back and forth around 182.62 in the above example.
上記実施例によれば、副走査方向の焦点距離を。According to the above embodiment, the focal length in the sub-scanning direction.
ｆＯレンズを構成する凹シリンダーレンズ１４と、ｆＯ
レンズと走査結像面１６との間に配置した凸シリンダー
レンズ１５とによって短焦点化したので、回転多面鏡の
傾きや軸ずれ等の影響によって発生する走査結像面上で
のビームスポットの偏移が少なくなる。そのため１回転
多面鏡の加工誤差やモータ軸のぶれや傾き及び回転多面
鏡と駆動軸との組立調整精度等を著しく緩和することが
可能となり、大幅なコスト低減を図ることができる。ま
た、回転多面鏡の反射面に入射する光束は平行光束であ
るため、反射面の汚れや傷等の影響を受は鴬く、反射面
の焼きつき現象が緩和されて装置の品質を長時間にわた
って保つことができる。The concave cylinder lens 14 constituting the fO lens and the fO
Since the convex cylinder lens 15 placed between the lens and the scanning imaging plane 16 has a short focus, the beam spot on the scanning imaging plane can be prevented from being deflected due to the influence of the tilt of the rotating polygon mirror, axis misalignment, etc. There will be less movement. Therefore, it is possible to significantly reduce processing errors of the single-rotation polygon mirror, vibration and inclination of the motor shaft, assembly adjustment accuracy between the rotary polygon mirror and the drive shaft, etc., and it is possible to significantly reduce costs. In addition, since the light beam that enters the reflective surface of the rotating polygon mirror is a parallel light beam, it is not affected by dirt or scratches on the reflective surface, and the burn-in phenomenon of the reflective surface is alleviated, increasing the quality of the device for a long time. can be kept for a long time.
さらに、ｆＤレンズの設計において、副走査方向のシリ
ンダーレンズのパワーが負のパワーと正のパワーで合成
されるため、収差補正が良好となり、走査結像面での収
束特性の向上を図ることができる。Furthermore, in the fD lens design, the power of the cylinder lens in the sub-scanning direction is combined with negative power and positive power, which improves aberration correction and improves convergence characteristics on the scanning imaging plane. can.
また、凸シリンダーレンズ１５の焦点位置即ち副走査方
向の焦点位置を、走査結像面１６上にある主走査方向の
焦点位置Ｐａの前後に変位させることにより、結像レン
ズ系への入射光束が略真円状の光束であっても、走査結
像面１６上での光束を略真円状にすることができ、上記
結像レンズ系への入射光束を楕円形にする必要はないか
ら、ビーム形状補正用の光学系は不要であり、レンズ系
のアライメントが簡単でレンズエレメントも少なく、コ
ストの安い光走査装置を提供することができる。さらに
、必要に応じて凸シリンダーレンズ１５を変位させるこ
とにより、副走査方向に長いビーム形状を得ることもで
きる。In addition, by displacing the focal position of the convex cylinder lens 15, that is, the focal position in the sub-scanning direction, before and after the focal position Pa in the main scanning direction on the scanning imaging plane 16, the incident light beam to the imaging lens system is Even if the beam is approximately circular, the beam on the scanning imaging plane 16 can be made approximately circular, and there is no need to make the beam incident on the imaging lens system elliptical. An optical system for beam shape correction is not required, alignment of the lens system is simple, the number of lens elements is small, and an inexpensive optical scanning device can be provided. Furthermore, by displacing the convex cylinder lens 15 as necessary, a beam shape that is long in the sub-scanning direction can be obtained.
また、上記実施例によれば、主走査方向の曲率半径が無
限大の面にシリンダー面を形成してなるレンズニレメン
１へ１４を結像レンズ系に用いたので、結像レンズ系を
構成するレンズエレメントの加工性が向上する。Further, according to the above embodiment, since the lenses 1 to 14, which are formed by forming a cylinder surface on a surface with an infinite radius of curvature in the main scanning direction, are used in the imaging lens system, the lenses constituting the imaging lens system Improves workability of elements.
第９図は上記実施例１の主走査方向の収差図である。FIG. 9 is an aberration diagram in the main scanning direction of the first embodiment.
第６図乃至第８図は本発明に係る光走査装置の別の光学
配置例を示す。この例は、結像レンズ系を構成するｆＯ
レンズが、光源側が球面、結像面側が曲率半径無限大面
でなるレンズエレメント１３と、光源側が凹シリンダー
面、結像面側が球面でなるレンズエレメント１４と、こ
れらレンズエレメント１３．１４間に配置されていて、
各面が球面でなるレンズエレメント１３′ とで構成
されている点が第３図乃至第５図の例と異なっており、
その池のモカ成は第３図乃至第５図の例と同じである。6 to 8 show other examples of optical arrangement of the optical scanning device according to the present invention. In this example, fO that constitutes the imaging lens system is
A lens element 13 has a spherical surface on the light source side and a surface with an infinite radius of curvature on the image forming surface side, a lens element 14 has a concave cylindrical surface on the light source side and a spherical surface on the image forming surface side, and is arranged between these lens elements 13 and 14. has been,
It differs from the examples shown in FIGS. 3 to 5 in that it is composed of a lens element 13' each of which has a spherical surface.
The mocha composition of the pond is the same as the examples shown in Figs. 3 to 5.
次に、上記第６図乃至第８図の光学配置例に基づ〈実施
例２及び実施例３を示す。Next, Example 2 and Example 3 will be described based on the optical arrangement examples shown in FIGS. 6 to 8 above.
実施例２
ν Ｒ（主） Ｒ（副）ｄ Ｎ１
ω ｏｏ １２．５２
−２６．８ −２６．８ ２．７ １
．５１１１８３ −６０．５９ −６０．５９
６．５２４ −７８．２６ −７８．２
６ ７．７１ １．７８５７１５ −４２．
１８ −４２．１８ ０．９８６
ｏｏ−１４６，０７８，７１，７８５７１７−１３０，
３４７−１３０，３４７９５，３３４８ω
３０．０ ５．０ １．５１２２７ｇ
ｏｏ ｏｏ ５０．０００
ｆＡ＝ １２５．０００ｍｍ
ｆ１３＝ ５０．６９０８ｍｍ
第１０図は上記実施例２における主走査方向の収差図で
ある。Example 2 ν R (main) R (secondary) d N1
ω oo 12.52
-26.8 -26.8 2.7 1
．． 511183 -60.59 -60.59
6.524 -78.26 -78.2
6 7.71 1.785715 -42.
18 -42.18 0.986
oo-146,078,71,785717-130,
347-130, 34795, 3348ω
30.0 5.0 1.51227g
oo oo 50.000
fA=125.000mm f13=50.6908mm FIG. 10 is an aberration diagram in the main scanning direction in the second embodiment.
実施例３
ν Ｒ（主） Ｒ（副）ｄ ＮＬ
ｃ−） ＣＩ：＋１８．０２ −３８．５
９ −３８．５９ ：１１．８８ １．５１１１
８３ −８７．２１ −８７．２１ ９．３８４
−１１２．６８ −１１２．６８ １１．１ １．
７８５７１５ −６０．７３ −６０．７３ １
．４３６ ０１１） −２００，９３１２，５
２１，７８５７１７−１８７，７−１８７，７１６０，
７１１５８００２８，８５，０，１，５１２２７９ω
００ ５０．０００
ｆＡ＝１８０．００ｍｎ＋
ｆ［ｌ＝ ５０．４５＋＋ｖ
上記実施例２、実施例３の場合も、前記実施例１につい
て述べたような作用効果を奏する。Example 3 ν R (main) R (secondary) d NL
c-) CI: +18.02 -38.5
9 -38.59 :11.88 1.5111
83 -87.21 -87.21 9.384
-112.68 -112.68 11.1 1.
785715 -60.73 -60.73 1
．． 436 011) -200,9312,5
21,785717-187,7-187,7160,
711580028,85,0,1,512279ω
00 50.000 fA=180.00mn+f[l=50.45++v The above embodiments 2 and 3 also have the same effects as described for the above embodiment 1.
ここで、ビームスポット径の許容値をｄｓとすると、副
走査方向の焦点距離ｆＢは。Here, if the allowable value of the beam spot diameter is ds, then the focal length fB in the sub-scanning direction is.
１．５／ｄｓ＜ｆＢ＜ ６ ／ｄｓ
とすることが好ましい。上記条件のうちの下限１．５／
ｄｓを越えると副走査方向の結像特性が悪化して解析限
界内に納めることができくなり、上限６／ｄｓを越える
と副走査方向での焦点距離が長くなり、前記（１）式よ
り許容される傾き誤差Δ０が微小となって本来の目的を
達することができなくなる。It is preferable that 1.5/ds<fB<6/ds. The lower limit of the above conditions is 1.5/
If the upper limit of 6/ds is exceeded, the imaging characteristics in the sub-scanning direction will deteriorate and it will not be possible to keep it within the analysis limit, and if the upper limit of 6/ds is exceeded, the focal length in the sub-scanning direction will become longer, and according to equation (1) above, The allowable tilt error Δ0 becomes so small that the original purpose cannot be achieved.
（発明の効果）
本発明によれば、結像レンズ系と走査結像面との間の凸
シリンダーレンズを光軸方向に移動調整して、副走査方
向の焦点位置を走査結像面上にある主走査方向の焦点位
置からずらすことにより、結像レンズ系への入射光束が
略真円状の光束であっても、走査結像面上での光束を略
真円状にすることができ、上記結像レンズ系への入射光
束を楕円形にするための補正用光学系は不要であるから
。(Effects of the Invention) According to the present invention, the convex cylinder lens between the imaging lens system and the scanning imaging plane is moved and adjusted in the optical axis direction, and the focal position in the sub-scanning direction is set on the scanning imaging plane. By shifting the focus position from a certain main scanning direction, even if the light beam incident on the imaging lens system is a substantially perfect circle, the light beam on the scanning imaging plane can be made into a substantially perfect circle. , since there is no need for a correction optical system for making the light beam incident on the imaging lens system elliptical.
レンズ系のアライメントが簡単でレンズエレメントも少
なく、コストの安い光走査装置を提供することができる
。It is possible to provide a low-cost optical scanning device in which the alignment of the lens system is simple and the number of lens elements is small.
また、副走査方向の焦点距離を、ｆθシリンダ構成する
凹シリンダーと、ｆθシリンダ走査結像面との間に配置
した凸シリンダーレンズとによって短焦点化できるので
１回転多面鏡の傾きや軸ずれ等の影響によって発生する
走査結像面上でのビームスポットの偏移が少なくなる。In addition, the focal length in the sub-scanning direction can be shortened by the concave cylinder constituting the fθ cylinder and the convex cylinder lens placed between the fθ cylinder scanning imaging surface, so that the tilt and axis deviation of the single rotation polygon mirror can be reduced. The deviation of the beam spot on the scanning imaging plane due to the influence of is reduced.
そのため１回転多面鏡の加工誤差やモータ軸のぶれや傾
き及び回転多面鏡と駆動軸との組立調整精度等を著しく
緩和することが可能となり、大幅なコスト低減を図るこ
とができる。また１回転多面鏡の反射面に入射する光束
は平行光束であるため、反射面の汚れや傷等の影響を受
は鴛＜１反射面の焼きつき現象が緩和されて装置の品質
を長時間にわたって保つことができる。Therefore, it is possible to significantly reduce processing errors of the single-rotation polygon mirror, vibration and inclination of the motor shaft, assembly adjustment accuracy between the rotary polygon mirror and the drive shaft, etc., and it is possible to significantly reduce costs. In addition, since the light beam incident on the reflective surface of a single-rotation polygon mirror is a parallel light beam, it is not affected by dirt or scratches on the reflective surface. can be kept for a long time.
さらに、ｆＯシリンダパワーの設計において。Furthermore, in the design of fO cylinder power.
副走査方向のシリンダーレンズパワーが負のパワーと正
のパワーで合成されるため、収差補正が良好となり、走
査結像面での収束特性の向上を図ることができる。Since the cylinder lens power in the sub-scanning direction is combined with negative power and positive power, aberration correction becomes good and convergence characteristics on the scanning imaging plane can be improved.
第１図は本発明に係る光走査装置の基本構成を示す光学
配置図、第２図は同上要部拡大図、第３図は本発明に係
る光走査装置の一つの光学配置例を示す斜視図、第４図
は同上平面図、第５図は同上正面図、第６図は本発明に
係る光走査装置の別の光学配置例を示す斜視図、第７図
は同上平面図、第８図は同上正面図、第９図は実施例１
の主走査方向の収差図、第１０図は実施例２の主走査方
向の収差図、第１１図は従来の光走査装置の例を示す平
面図、第１２図は同上正面図である。
１．１１・・・・平行光束、２．１２・・・・光偏向器
どしての回転多面鏡、３・・・・結像レンズ系、 １３
．１３’。
１４・・・・レンズエレメント、６．１５・・・・凸シ
リンダーレンズ、７，１６・・・・走査結像面、Ｐｏ・
・・・主走査方向の焦点位置。
（ほか１名）
■７ 口
最 ３ 口
ＳＡ（味面吠動 ＡＳ（＊魚吠序） ｆθ竹Ｊｉｆ
ｔ７ 目
軸外力メリルオアｌし力内の横吠え
θ７ｔｔｔ −／、００口
１
りｔシ ４Ｉ
、２
う ４Ｚ口FIG. 1 is an optical layout diagram showing the basic configuration of the optical scanning device according to the present invention, FIG. 2 is an enlarged view of the main parts of the same, and FIG. 3 is a perspective view showing an example of the optical layout of the optical scanning device according to the present invention. 4 is a plan view of the same, FIG. 5 is a front view of the same, FIG. 6 is a perspective view showing another example of optical arrangement of the optical scanning device according to the present invention, FIG. The figure is a front view of the same as above, and FIG. 9 is Example 1
10 is an aberration diagram in the main scanning direction of Example 2, FIG. 11 is a plan view showing an example of a conventional optical scanning device, and FIG. 12 is a front view of the same. 1.11... Parallel light beam, 2.12... Rotating polygon mirror as optical deflector, 3... Imaging lens system, 13
．． 13'. 14...Lens element, 6.15...Convex cylinder lens, 7,16...Scanning imaging plane, Po.
...Focus position in the main scanning direction. (1 other person) ■7 Kuchi Sai 3 Kuchi SA (Taste Mentoring AS (*Fish Order) fθ Bamboo Jif
t7 Eye axis external force Meryl or l and horizontal bark within the force θ7ttt −/, 00 mouth
1 Ritshi 4I, 2 U 4Z mouth
Claims (1)
して照射する照射手段と、この照射手段からの光束を偏
向する光偏向器と、この光偏向器により偏向された上記
光束を結像させるための結像レンズ系と、この結像レン
ズ系と走査結像面との間に配置された凸シリンダーレン
ズとを有してなる光走査装置であって、上記結像レンズ
系を複数のレンズエレメントによるｆθレンズで構成し
、このｆθレンズの複数のレンズエレメントのうちの少
なくとも一つの面を主走査方向に曲率半径が無限大とな
る曲率無限大面とし、この曲率無限大面に凹シリンダー
レンズ面を設け、主走査方向の焦点位置を上記走査結像
面に一致させると共に、上記凸シリンダーレンズを光軸
方向に移動調整して副走査方向の焦点位置を上記走査結
像面より所定量光軸方向へずらし、走査結像面における
副走査方向のビーム径を主走査方向のビームウェストと
略同一にしたことを特徴とする光走査装置。irradiation means for irradiating a light beam from a light source as a substantially circular parallel light beam with a predetermined diameter; a light deflector for deflecting the light beam from the irradiation means; and an image-forming of the light beam deflected by the light deflector. An optical scanning device comprising: an imaging lens system for scanning, and a convex cylinder lens disposed between the imaging lens system and a scanning imaging surface, the imaging lens system comprising a plurality of lenses. At least one surface of the plurality of lens elements of this f-theta lens is an infinite curvature surface whose radius of curvature is infinite in the main scanning direction, and a concave cylinder lens is attached to this infinite curvature surface. The focal position in the main scanning direction is made to coincide with the scanning imaging plane, and the convex cylinder lens is moved and adjusted in the optical axis direction to adjust the focal position in the sub scanning direction by a predetermined amount of light from the scanning imaging plane. An optical scanning device characterized in that the beam diameter in the sub-scanning direction on the scanning imaging plane is made substantially the same as the beam waist in the main-scanning direction by shifting in the axial direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62051055A JPS63216018A (en) | 1987-03-05 | 1987-03-05 | Optical scanner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62051055A JPS63216018A (en) | 1987-03-05 | 1987-03-05 | Optical scanner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63216018A true JPS63216018A (en) | 1988-09-08 |
Family
ID=12876119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62051055A Pending JPS63216018A (en) | 1987-03-05 | 1987-03-05 | Optical scanner |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63216018A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0764868A1 (en) * | 1995-09-22 | 1997-03-26 | Dainippon Screen Mfg. Co., Ltd. | Method of correcting curvature of image surface and optical beam scanning apparatus for use with the same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5984218A (en) * | 1982-10-08 | 1984-05-15 | ゼロツクス・コ−ポレ−シヨン | Flying spot scanner |
| JPS60263917A (en) * | 1984-06-12 | 1985-12-27 | Iwatsu Electric Co Ltd | Correcting optical device for astigmatism |
-
1987
- 1987-03-05 JP JP62051055A patent/JPS63216018A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5984218A (en) * | 1982-10-08 | 1984-05-15 | ゼロツクス・コ−ポレ−シヨン | Flying spot scanner |
| JPS60263917A (en) * | 1984-06-12 | 1985-12-27 | Iwatsu Electric Co Ltd | Correcting optical device for astigmatism |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0764868A1 (en) * | 1995-09-22 | 1997-03-26 | Dainippon Screen Mfg. Co., Ltd. | Method of correcting curvature of image surface and optical beam scanning apparatus for use with the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH0627904B2 (en) | Laser beam scanning optics | |
| US4796962A (en) | Optical scanner | |
| JP2563260B2 (en) | Optical beam scanning device | |
| US5566016A (en) | Laser beam scanner | |
| JP3104618B2 (en) | Optical scanning device and optical lens | |
| EP0813087B1 (en) | Beam scanning apparatus | |
| US6108115A (en) | Scanning optical system | |
| US4586782A (en) | Laser beam optical system with inclined cylindrical lens | |
| JP2001021822A (en) | Optical scanning optical system and image forming device using the system | |
| JPS63216018A (en) | Optical scanner | |
| JPH08248345A (en) | Optical scanner | |
| JP3308342B2 (en) | Semiconductor laser array light source device | |
| JP3472205B2 (en) | Optical scanning optical device and image forming apparatus using the same | |
| JP4418567B2 (en) | Multi-beam scanning optical system and image forming apparatus using the same | |
| JP2657381B2 (en) | Light flux adjusting method for scanning optical device | |
| JPH08179236A (en) | Beam scanner | |
| JP3571808B2 (en) | Optical scanning optical system and laser beam printer including the same | |
| JP3680891B2 (en) | Optical scanning device | |
| JPH112769A (en) | Optical scanner | |
| JP3069281B2 (en) | Optical scanning optical system | |
| JP2750597B2 (en) | High density scanning device | |
| JPS6355517A (en) | Optical scanner | |
| JP3198685B2 (en) | Light beam scanning device | |
| JP3725182B2 (en) | Optical scanning device | |
| JP2834802B2 (en) | Optical scanning device |