JP3073801B2 - Optical scanning lens and optical scanning device - Google Patents

Optical scanning lens and optical scanning device

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Publication number
JP3073801B2
JP3073801B2 JP21236991A JP21236991A JP3073801B2 JP 3073801 B2 JP3073801 B2 JP 3073801B2 JP 21236991 A JP21236991 A JP 21236991A JP 21236991 A JP21236991 A JP 21236991A JP 3073801 B2 JP3073801 B2 JP 3073801B2
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JP
Japan
Prior art keywords
lens
optical scanning
optical
light beam
light
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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Application number
JP21236991A
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Japanese (ja)
Other versions
JPH0553067A (en
Inventor
保夫 石崎
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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Priority to JP21236991A priority Critical patent/JP3073801B2/en
Publication of JPH0553067A publication Critical patent/JPH0553067A/en
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Description

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

【0001】[0001]

【産業上の利用分野】この発明は、光走査用レンズおよ
び光走査装置に関する
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning lens and an optical scanning device.

【0002】[0002]

【従来の技術】等角速度的に偏向する光束を、光走査用
レンズにより被走査面上に光スポットとして集光させて
被走査面を等速的に光走査する光偏向装置は従来から広
く知られている。このような光走査装置において、光源
から被走査面に到る光束光路を直線的に展開した「仮想
光路」を想定し、この仮想光路上で主走査方向と平行に
なる方向を「主走査対応方向」と称し、上記仮想光路上
で副走査方向と平行になる方向を「副走査対応方向」と
称する。上記のような光走査装置においては、周期的に
繰り返される光走査の走査起点を揃えるために、光走査
領域へと偏向する偏向光束を同期検知用光センサーで検
出して同期検出信号を発生させ、この同期検出信号発生
から所定時間後に光走査を開始することが行なわれてい
る。この場合、同期検知用光センサーは、光走査用レン
ズにより光スポットが形成される被走査面と同一の平面
内に配備するのが好ましい。被走査面と同一の面内では
偏向光束が小さい径のスポットに集光しているので、同
期検知用光センサーの小さな受光面でも確実に偏向光束
を検出できるからである。
2. Description of the Related Art Optical deflecting devices that converge a light beam deflected at a constant angular velocity as a light spot on a surface to be scanned by an optical scanning lens and optically scan the surface to be scanned at a constant speed have been widely known. Have been. In such an optical scanning device, assuming a “virtual optical path” in which a light beam path from the light source to the surface to be scanned is linearly developed, a direction parallel to the main scanning direction on this virtual optical path is referred to as “a main scanning direction”. A direction parallel to the sub-scanning direction on the virtual optical path is referred to as a “sub-scanning corresponding direction”. In the optical scanning device as described above, in order to align the scanning starting points of the periodically repeated optical scanning, a synchronous detection signal is generated by detecting a deflecting light beam deflected to the optical scanning region by a synchronous detection optical sensor. The optical scanning is started after a predetermined time from the generation of the synchronization detection signal. In this case, it is preferable that the synchronization detection optical sensor be provided in the same plane as the surface to be scanned on which the light spot is formed by the optical scanning lens. This is because the deflected light beam is focused on a spot having a small diameter in the same plane as the surface to be scanned, so that the deflected light beam can be reliably detected even on the small light receiving surface of the synchronization detecting optical sensor.

【0003】しかし、被走査面には一般に、光導電性の
感光体等の感光性記録媒体が配備されるため、感光性記
録媒体の配備を妨げない位置に同期検知用光センサーを
配備する必要がある。これを実行するための方法として
「同期検知用光センサーの配備位置を、被走査面と同一
の平面内で光走査領域から離して設定する」方法がある
が、この方法の場合、光走査用レンズの主走査対応方向
のレンズ系が大きくなり、光走査用レンズの製造が難し
く、光走査用レンズのコスト高を招来するという問題が
ある。また、別の方法として「光走査用レンズによる集
光光束をミラー等により折り返し、被走査面と等価な位
置(上記ミラーにより被走査面の像が形成される位置)
に光センサーを配備する」方法があるが、ミラー等の配
置のための余分のスペースを必要とし、実際的見地から
すると、ミラーや同期検知用光センサーの配置に対する
制約が大きい。
However, since a photosensitive recording medium such as a photoconductive photosensitive member is generally provided on the surface to be scanned, it is necessary to provide an optical sensor for synchronization detection at a position which does not hinder the arrangement of the photosensitive recording medium. There is. As a method for performing this, there is a method of “setting the arrangement position of the synchronization detection optical sensor away from the optical scanning area in the same plane as the surface to be scanned”. There is a problem in that the lens system in the direction corresponding to the main scanning of the lens becomes large, it is difficult to manufacture the optical scanning lens, and the cost of the optical scanning lens is increased. As another method, “a light beam condensed by the optical scanning lens is turned back by a mirror or the like, and a position equivalent to the surface to be scanned (a position where an image of the surface to be scanned is formed by the mirror)
Although there is a method of “deploying an optical sensor”, extra space is required for the arrangement of a mirror and the like, and from a practical point of view, there are great restrictions on the arrangement of the mirror and the optical sensor for synchronization detection.

【0004】[0004]

【発明が解決しようとする課題】この発明は、上述した
事情に鑑みてなされたものであって、同期検知用光セン
サーの配置の自由度を大きくできる新規な光走査用レン
ズおよび、この光走査用レンズを用いる光走査装置の提
供を目的とする。
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a novel optical scanning lens capable of increasing the degree of freedom in the arrangement of a synchronous detection optical sensor, and a novel optical scanning lens. It is an object of the present invention to provide an optical scanning device using a lens.

【0005】[0005]

【課題を解決するための手段】請求項1の光走査用レン
ズは「光源からの光束を光偏向器により等角速度的に偏
向させ、偏向光束を結像レンズにより被走査面上に光ス
ポットとして集光せしめて光走査を行なう光走査装置」
において、偏向器と被走査面との間の光路上に配備され
るレンズである。上記光走査装置は、光偏向器における
所謂「面倒れ」の補正を行なわないことを前提とする。
According to a first aspect of the present invention, there is provided an optical scanning lens comprising: a light beam from a light source is deflected at an equal angular velocity by an optical deflector, and the deflected light beam is formed as a light spot on a surface to be scanned by an imaging lens. Optical scanning device that performs optical scanning by focusing light. "
, A lens provided on the optical path between the deflector and the surface to be scanned. The above optical scanning device is based on the premise that correction of so-called "surface tilt" in the optical deflector is not performed.

【0006】請求項1記載の光走査用レンズは「結像レ
ンズ部分と同期検出用レンズ部分とを一体化した単体構
造」を有する。「結像レンズ部分」は、偏向光束を被走
査面上に光スポットとして集光させる機能とリニアリテ
ィ補正機能を持ち、「同期検出用レンズ部分」は、偏向
光束を同期検知用光センサー上に集光させる機能を有す
る。結像レンズ部分と同期検出用レンズ部分とは異なる
結像特性を有する。ここに、「結像特性が異なる」と
は、上記各レンズ部分が、焦点距離および/または光軸
を異にすることを意味する。光走査用レンズは、全体が
プラスチックによりモールド成形される。モールド成形
で一体成形される際「モールド成形におけるゲートの側
で、同期検出用レンズ部分が成形」される。上記請求項
1記載の光走査用レンズは、「同期検出用レンズ部分
が、同期検知用の偏向光束を、光走査用の偏向領域から
遠ざける」ように、光軸を調整して形成することができ
る(請求項2)。
The optical scanning lens according to the first aspect has a "single structure in which the imaging lens portion and the synchronization detecting lens portion are integrated". The “imaging lens part” has the function of condensing the deflected light beam as a light spot on the surface to be scanned and the linearity correction function, and the “synchronization detection lens part” collects the deflected light beam on the synchronization detection optical sensor. It has the function of light. The imaging lens portion and the synchronization detection lens portion have different imaging characteristics. Here, "different imaging characteristics" means that the respective lens portions have different focal lengths and / or optical axes. The optical scanning lens is entirely molded from plastic. When integrally molded by molding, “the lens portion for synchronization detection is molded on the side of the gate in molding”. The optical scanning lens according to claim 1 may be formed by adjusting the optical axis such that the synchronous detection lens portion moves the synchronous detection deflected light beam away from the optical scanning deflection area. (Claim 2).

【0007】請求項3記載の光走査装置は、上記のよう
な光走査用レンズを用いる光走査装置であって、「光源
装置」と、この光源装置からの光束を等角速度的に偏向
させる「光偏向器」と、この光偏向器による偏向光束を
被走査面上に光スポットとして集光させる上記「光走査
用レンズ」と、光走査の同期を取るための「同期検知用
光センサー」とを有する。請求項3記載の光走査装置
は、上述の如く、面倒れの補正を行なわないことを前提
とする。従って偏向器としては、面倒れを高精度に補正
した回転多面鏡や、原理的に面倒れの殆ど無いピラミダ
ルミラーやホゾ型ミラーを用いるのが望ましい。請求項
1記載の光走査用レンズに入射する偏向光束は、平行光
束でも、弱い発散性の光束でもあるいは、弱い収束性の
光束でも良い。偏向光束が平行光束である場合には、上
記リニアリティ補正機能は所謂fθ機能であり、結像レ
ンズ部分はfθレンズとなる。
An optical scanning device according to a third aspect of the present invention is an optical scanning device using the optical scanning lens as described above, wherein a "light source device" and a light beam from the light source device are deflected at a constant angular velocity. An optical deflector, the optical scanning lens for condensing the light beam deflected by the optical deflector as a light spot on the surface to be scanned, and an optical sensor for synchronization detection for synchronizing optical scanning. Having. The optical scanning device according to the third aspect is based on the premise that correction of surface tilt is not performed as described above. Therefore, as the deflector, it is desirable to use a rotating polygon mirror whose surface tilt is corrected with high accuracy, a pyramidal mirror or a tenon type mirror which has almost no surface tilt in principle. The deflected light beam incident on the optical scanning lens according to claim 1 may be a parallel light beam, a weakly divergent light beam, or a weakly convergent light beam. When the deflected light beam is a parallel light beam, the linearity correction function is a so-called fθ function, and the imaging lens portion is an fθ lens.

【0008】請求項4記載の光走査用レンズは「光源か
らの光束を主走査対応方向に長い線像として結像させ、
線像の結像位置の近傍に偏向反射面を持つ光偏向器によ
り等角速度的に偏向させ、偏向光束を結像レンズにより
被走査面上に光スポットとして集光せしめて光走査を行
なう光走査装置」において、偏向器と被走査面との間の
光路上に配備されるレンズである。この光走査用レンズ
の用いられる光走査装置は上記のように「面倒れ」を補
正する機能を持っている。請求項4の光走査用レンズ
は、請求項1の光走査用レンズと同じく、結像レンズ部
分と同期検出用レンズ部分とを一体化して成る単体構造
である。「結像レンズ部分」は、主走査対応方向に関し
てリニアリティ補正機能を持ち、副走査対応方向に関し
ては「偏向反射面位置と被走査面位置とを幾何光学的に
略共役な関係とする」機能を有し、偏向光束を被走査面
上に光スポットとして集光させる。「同期検出用レンズ
部分」は、偏向光束を同期検知用光センサー上に集光さ
せ、結像レンズ部分と同期検出用レンズ部分とは異なる
結像特性を有する。即ち、結像レンズ部分と同期検出用
レンズ部分とは、少なくとも主走査対応方向に関して、
焦点距離および/または光軸が異なる。光走査用レンズ
は、全体がプラスチックによりモールド成形される。モ
ールド成形で一体成形される際「モールド成形における
ゲートの側で、同期検出用レンズ部分が成形」される。
上記請求項4記載の光走査用レンズは、「同期検出用レ
ンズ部分が、同期検知用の偏向光束を、光走査用の偏向
領域から遠ざける」ように、光軸を調整して形成するこ
とができる(請求項5)。
According to a fourth aspect of the present invention, there is provided an optical scanning lens which forms a light beam from a light source as a long line image in a main scanning direction,
Optical scanning in which light is deflected at an equal angular velocity by an optical deflector having a deflecting and reflecting surface near the image forming position of a line image, and the deflected light beam is condensed as a light spot on a surface to be scanned by an imaging lens to perform optical scanning. In the "device", it is a lens provided on the optical path between the deflector and the surface to be scanned. The optical scanning device using the optical scanning lens has a function of correcting "surface tilt" as described above. An optical scanning lens according to a fourth aspect is a single-piece structure formed by integrating an imaging lens portion and a synchronization detection lens portion, like the optical scanning lens according to the first aspect. The "imaging lens portion" has a linearity correction function in the main scanning corresponding direction, and has a function of "making the position of the deflecting reflection surface and the position of the scanned surface substantially geometrically optically conjugate" in the sub-scanning corresponding direction. And converges the deflected light beam as a light spot on the surface to be scanned. The "synchronous detection lens portion" focuses the deflected light beam on the synchronous detection optical sensor, and has different imaging characteristics from those of the imaging lens portion and the synchronous detection lens portion. That is, the imaging lens portion and the synchronization detection lens portion are at least in the main scanning corresponding direction.
Different focal lengths and / or optical axes. The optical scanning lens is entirely molded from plastic. When integrally molded by molding, “the lens portion for synchronization detection is molded on the side of the gate in molding”.
The optical scanning lens according to the fourth aspect may be formed by adjusting the optical axis such that the synchronous detection lens portion moves the deflection light flux for synchronization detection away from the light scanning deflection area. (Claim 5).

【0009】請求項6の光走査装置は、請求項4または
5に記載の光走査用レンズを用いる光走査装置である。
この光走査装置は、「光源装置」と、この光源装置から
の光束を主走査対応方向に長い線像として結像せしめる
「線像結像光学系」と、線像の結像位置近傍に偏向反射
面を持ち光束を等角速度的に偏向させる「光偏向器」
と、この光偏向器による偏向光束を被走査面上に光スポ
ットとして集光させる上記「光走査用レンズ」と、光走
査の同期を取るための「同期検知用光センサー」とを有
する。上述の如く、この光走査装置は面倒れを補正する
機能を有するので、光偏向器として、通常の回転多面鏡
等を用いることができる。光走査用レンズに入射する偏
向光束は、副走査対応方向には発散性であるが、主走査
対応方向においては、平行・弱い発散性・弱い収束性の
何れでも良く、偏向光束が主走査対応方向に関して平行
光束であるときは、結像レンズ部分は周知のアナモフィ
ックなfθレンズとなる。
An optical scanning device according to a sixth aspect is an optical scanning device using the optical scanning lens according to the fourth or fifth aspect.
This optical scanning device includes a “light source device”, a “line image forming optical system” for forming a light beam from the light source device as a long line image in the main scanning direction, and a light source near the image forming position of the line image. "Optical deflector" that has a reflective surface and deflects a light beam at a uniform angular velocity
The "optical scanning lens" for condensing the light beam deflected by the optical deflector as a light spot on the surface to be scanned, and the "optical sensor for synchronization detection" for synchronizing optical scanning. As described above, this optical scanning device has a function of correcting surface tilt, so that an ordinary rotating polygon mirror or the like can be used as an optical deflector. The deflected light beam incident on the optical scanning lens is divergent in the sub-scanning direction, but may be parallel, weakly divergent, or weakly convergent in the main scanning direction. When the light flux is parallel in the direction, the imaging lens portion becomes a well-known anamorphic fθ lens.

【0010】なお、請求項1または4において、「偏向
光束を同期検出用光センサー上に集光させる」とは、少
なくとも主走査対応方向において、同期検出用光センサ
ーの受光面内に偏向光束が収束することを意味し、偏向
光束が上記受光面上に像として結像している必要は必ず
しもない。
In the first or fourth aspect, "condensing the deflected light beam on the synchronization detecting optical sensor" means that the deflected light beam is present in the light receiving surface of the synchronization detecting optical sensor at least in the main scanning corresponding direction. This means that the light beam converges, and it is not always necessary for the deflected light beam to form an image on the light receiving surface.

【0011】[0011]

【作用】この発明では上記の如く、光走査用レンズが結
像レンズ部分と同期検出用レンズ部分とを一体化して構
成されるが、結像レンズ部分と同期検出用レンズ部分と
が、異なる結像特性を持つので、同期検知用光センサー
の所望の配置位置に応じて、同期検出用レンズ部分の焦
点距離や光軸を調整して、偏向光束を適正に同期検出用
光センサーの受光面上に集光することができる。請求項
1,2,4,5に記載の光走査用レンズのような、細長
いレンズをモールド成形する場合、成形時のゲートは、
長手方向の一方の側に位置されるのが普通である。ゲー
トの近傍では成形の精度が低下しやすい。このため、レ
ンズ面の精度は、レンズ長手方向のゲートから遠い側で
高く、ゲートに近い側で低くなり、光軸に関して非対称
に成り易い。この発明の光走査用レンズのように、結像
レンズ部分の長手方向端部に同期検出用レンズ部分を一
体的に形成する場合、同期検出用レンズ部分のレンズ面
精度は、結像レンズ部分に比して比較的ラフで良いの
で、上記ゲートを同期検出用レンズ部分側にすることに
より、結像レンズ部分でのレンズ面精度の低下を有効に
防止することができる。また、請求項2,5記載の光走
査用レンズのように「同期検出用レンズ部分が、同期検
知用の偏向光束を、光走査用の偏向領域から遠ざける」
ように、光軸を調整して形成すると、同期検知用光セン
サーの配備位置を光走査用の偏向領域から遠ざけること
ができ、同期検知用光センサーにより、走査光が「ケラ
れ」ないようにすることができ、同期検知用光センサー
の配置位置の自由度が大きくなる。
According to the present invention, as described above, the optical scanning lens is formed by integrating the imaging lens portion and the synchronization detection lens portion. However, the imaging lens portion and the synchronization detection lens portion are different from each other. Since it has image characteristics, the focal length and optical axis of the synchronization detection lens are adjusted according to the desired position of the synchronization detection optical sensor, and the deflected light beam is properly adjusted on the light receiving surface of the synchronization detection optical sensor. Can be collected. When molding an elongated lens, such as the optical scanning lens according to claims 1, 2, 4, and 5, the gate at the time of molding is:
It is usually located on one side in the longitudinal direction. In the vicinity of the gate, the precision of molding tends to decrease. For this reason, the accuracy of the lens surface is higher on the side farther from the gate in the lens longitudinal direction, lower on the side closer to the gate, and tends to be asymmetric with respect to the optical axis. When the synchronization detection lens portion is integrally formed at the longitudinal end of the imaging lens portion as in the optical scanning lens of the present invention, the lens surface accuracy of the synchronization detection lens portion is equal to that of the imaging lens portion. Since the gate may be relatively rough as compared with the above, by setting the gate on the side of the lens portion for synchronization detection, it is possible to effectively prevent a decrease in lens surface accuracy in the imaging lens portion. Further, as in the optical scanning lens according to the second and fifth aspects, "the synchronous detection lens portion moves the deflection light beam for synchronization detection away from the deflection region for optical scanning."
As described above, when the optical axis is adjusted and formed, the arrangement position of the optical sensor for synchronization detection can be moved away from the deflection area for optical scanning, and the optical sensor for synchronization detection prevents the scanning light from being "blurred". Therefore, the degree of freedom of the arrangement position of the optical sensor for synchronization detection is increased.

【0012】[0012]

【実施例】以下、図面に即して具体的な実施例を説明す
る。図1(a)に示す光走査装置は、請求項6の光走査
装置の1実施例である。
BRIEF DESCRIPTION OF THE DRAWINGS FIG. The optical scanning device shown in FIG. 1A is an embodiment of the optical scanning device according to claim 6.

【0013】光源装置1は、半導体レーザーや発光ダイ
オード等の光源とコリメートレンズとの組合せにより構
成され、実質的な平行光束を放射する。放射された平行
光束は、線像結像光学系としてのシリンダーレンズ2に
より、副走査対応方向にのみ集束性を与えられ、光偏向
器である回転多面鏡3の偏向反射面の近傍に、主走査対
応方向に長い線像として結像し、偏向反射面により反射
される。反射光束は、回転多面鏡3の回転により、等角
速度的に偏向する偏向光束となって光走査用レンズ4に
入射し、被走査面に向かって収束する。被走査面には、
母線を被走査面に合致させて、ドラム状の光導電性感光
体5が配備されており、光走査に同期して矢印方向へ回
転し、光走査される感光体周面を副走査方向へ送る。偏
向光束は、各光走査に先立って、同期検知用光センサー
8により検知され、光走査の同期がとられる。
The light source device 1 is composed of a combination of a light source such as a semiconductor laser or a light emitting diode and a collimating lens, and emits a substantially parallel light beam. The emitted parallel light beam is given a converging property only in the sub-scanning corresponding direction by the cylinder lens 2 as a line image forming optical system, and is focused near the deflection reflecting surface of the rotary polygon mirror 3 which is an optical deflector. It forms an image as a long line image in the scanning corresponding direction, and is reflected by the deflecting / reflecting surface. The reflected light flux becomes a deflected light flux deflected at a constant angular velocity by the rotation of the rotary polygon mirror 3, enters the optical scanning lens 4, and converges toward the surface to be scanned. On the scanned surface,
A drum-shaped photoconductive photoconductor 5 is provided with the generatrix aligned with the surface to be scanned. The drum-shaped photoconductive photoconductor 5 rotates in the direction of the arrow in synchronization with the optical scanning, and moves the peripheral surface of the photoconductor to be optically scanned in the sub-scanning direction. send. Prior to each optical scanning, the deflected light beam is detected by the synchronization detecting optical sensor 8, and the optical scanning is synchronized.

【0014】光走査用レンズ4は、図1(b)に示すよ
うに、結像レンズ部分41と同期検出用レンズ部分42
とが一体化された単体構造である。結像レンズ部分41
はアナモフィックなfθレンズであり、主走査対応方向
に関してfθ機能を有する。このため、結像レンズ部分
41により被走査面上に形成される光スポットは、感光
体表面を等速的に光走査する。同期検出用レンズ部分4
2は、偏向光束を同期検知用光センサー8に向かって集
光させる。同期検知用光センサー8は、光走査領域の光
走査開始側の側方において、光走査用レンズ4と被走査
面との間の所望の位置に配備されている。同期検出用レ
ンズ部分42は、その焦点距離を同期検知用光センサー
8の配備位置に応じて設定され、光走査領域に向かって
偏向する偏向光束を、同期検知用光センサー8の受光面
に向かって集光させる。同期検知用光センサー8は、例
えばPINフォトダイオード等であり、その受光面の径
は1〜2mm程度であるから受光面での集光状態は、少
なくとも主走査対応方向において、この受光面領域に集
光する程度で足りる。
As shown in FIG. 1B, the optical scanning lens 4 includes an imaging lens portion 41 and a synchronization detecting lens portion 42.
Is a unitary structure that is integrated. Imaging lens part 41
Is an anamorphic fθ lens, which has an fθ function in the main scanning corresponding direction. Therefore, the light spot formed on the surface to be scanned by the imaging lens portion 41 optically scans the surface of the photoconductor at a constant speed. Synchronous detection lens part 4
Reference numeral 2 focuses the deflected light beam toward the synchronization detection optical sensor 8. The synchronization detecting optical sensor 8 is provided at a desired position between the optical scanning lens 4 and the surface to be scanned on the side of the optical scanning area on the optical scanning start side. The synchronous detection lens portion 42 has its focal length set in accordance with the position where the synchronous detection optical sensor 8 is provided, and deflects a deflecting light beam that deflects toward the optical scanning area toward the light receiving surface of the synchronization detection optical sensor 8. To collect light. The light sensor 8 for synchronization detection is, for example, a PIN photodiode or the like, and its light receiving surface has a diameter of about 1 to 2 mm. It is enough to collect light.

【0015】この実施例において、結像レンズ部分41
は、光偏向器たる回転多面鏡3の面倒れを補正する機能
を有するが、同期検出用レンズ部分42は必ずしも面倒
れ補正機能を持たなくても良い。同期検出用レンズ部分
42に、面倒れ補正機能を持たせない場合には、同期検
知用光センサー8に入射する偏向光束が副走査対応方向
に変動して、場合によっては偏向光束の検出不全を生ず
る可能性もある。これを避けるためには、同期検知用光
センサー8の受光面上に集光する光束が副走査対応方向
に長い形状となるようにすれば良い。そのためには、同
期検出用レンズ部分42のパワーを、主・副走査対応方
向で異ならせれば良い。もっとも、説明中の実施例の場
合は、光走査用レンズ8に入射する偏向光束は主走査対
応方向には平行光束で、副走査対応方向には発散性であ
るので、同期検出用レンズ部分42を球面レンズとして
構成しても、同期検知用光センサー8の受光面に集光し
た光束状態は副走査対応方向に長いものとなるので問題
はない。
In this embodiment, the imaging lens portion 41
Has a function of correcting the tilt of the rotary polygon mirror 3 as an optical deflector, but the synchronization detection lens portion 42 does not necessarily have to have the tilt correction function. If the synchronization detection lens portion 42 is not provided with the surface tilt correction function, the deflection light beam incident on the synchronization detection optical sensor 8 fluctuates in the sub-scanning corresponding direction, and in some cases, the detection failure of the deflection light beam may occur. It can also happen. In order to avoid this, it is only necessary that the light beam condensed on the light receiving surface of the synchronization detecting optical sensor 8 be long in the sub-scanning corresponding direction. For this purpose, the power of the synchronization detection lens portion 42 may be made different in the main / sub-scanning corresponding directions. However, in the case of the embodiment being described, the deflected light beam incident on the optical scanning lens 8 is a parallel light beam in the main scanning corresponding direction and divergent in the sub scanning corresponding direction. Even if is configured as a spherical lens, there is no problem because the state of the light beam focused on the light receiving surface of the synchronization detection optical sensor 8 is long in the sub-scanning corresponding direction.

【0016】同期検出用レンズ部分42の大きさは主走
査対応方向に4〜5mm程度で良く、従って、この部分
を結像レンズ部分41に一体化しても、光走査用レンズ
4の大きさは、従来レンズとそれほど変わらない。光走
査用レンズ4は、プラスチックを材料として、モールド
成形により形成されている。前述の如く、光走査用レン
ズ4のような、細長いレンズをモールド成形する場合、
成形時のゲートを長手方向の一方の側に持つのが普通で
あり、レンズ面の精度は光軸に関して非対称に成り易い
が、この発明の光走査用レンズのように、結像レンズ部
分の長手方向端部に同期検出用レンズ部分を一体的に形
成する場合、同期検出用レンズ部分のレンズ面精度は、
結像レンズ部分に比して比較的ラフで良いので、上記ゲ
ートを同期検出用レンズ部分側にすることにより、結像
レンズ部分でのレンズ面精度の低下を有効に防止するこ
とができる。
The size of the synchronization detecting lens portion 42 may be about 4 to 5 mm in the main scanning corresponding direction. Therefore, even if this portion is integrated with the imaging lens portion 41, the size of the optical scanning lens 4 is It is not so different from conventional lenses. The optical scanning lens 4 is formed by molding a plastic material. As described above, when molding an elongated lens such as the optical scanning lens 4,
It is common to have a gate during molding on one side in the longitudinal direction, and the accuracy of the lens surface is likely to be asymmetric with respect to the optical axis. When the synchronization detection lens portion is integrally formed at the end of the direction, the lens surface accuracy of the synchronization detection lens portion is
Since the gate may be relatively rough as compared with the imaging lens portion, by setting the gate on the side of the synchronization detecting lens portion, it is possible to effectively prevent a decrease in lens surface accuracy in the imaging lens portion.

【0017】図2は、別の実施例を特徴部分のみ示して
いる。この実施例の場合、光偏向器3による有効偏向角
2θ1に対して、有効光走査偏向角2θ2が大きく、角θ
1−θ2が比較的小さい。そこで、同期検知用光センサー
8により、走査光が「ケラれ」ないように、光走査用レ
ンズ4Aの同期検出用レンズ部分42Aの光軸を調整し
て、同期検知用の偏向光束10の方向を光走査用の偏向
領域から遠ざけるようにし、同期検知用光センサー8の
配備位置を光走査用の偏向領域から遠ざけている(請求
項5)。以上、請求項5の光走査用レンズの実施例、請
求項6の光走査装置の実施例につき説明したが、図1の
構成において、シリンダーレンズ2を取り除くと、請求
項3の光走査装置の実施例になる。この装置の場合は、
光偏向器の面倒れを補正しないので、回転多面鏡3は面
倒れの生じないように、偏向反射面や回転軸の精度を十
分に高くしたものを用いるか、あるいは光偏向器として
ピラミダルミラーやホゾ型ミラーを用いる。勿論、光走
査用レンズの結像レンズ部分はアナモフィックにする必
要はなく、光軸の回りに回転対称なレンズ面を持つ通常
のfθレンズとすれば良い。
FIG. 2 shows another embodiment of the invention, in which only the characteristic portions are shown. In this embodiment, the effective deflection angle 2 [Theta] 1 by the optical deflector 3, the effective optical scanning deflection angle 2 [Theta] 2 is large, the angular θ
1 −θ 2 is relatively small. Therefore, the optical axis of the synchronous detection lens portion 42A of the optical scanning lens 4A is adjusted by the synchronous detection optical sensor 8 so that the scanning light is not "eclipsed", and the direction of the synchronous detection deflection light beam 10 is adjusted. Is located away from the optical scanning deflection area, and the position of the synchronization detecting optical sensor 8 is located away from the optical scanning deflection area (claim 5). The embodiment of the optical scanning lens according to claim 5 and the embodiment of the optical scanning device according to claim 6 have been described above. However, when the cylinder lens 2 is removed from the configuration of FIG. An example. For this device,
Since the tilting of the optical deflector is not corrected, the rotating polygon mirror 3 should have a sufficiently high accuracy of the deflecting reflecting surface and the rotating shaft so as to prevent tilting, or use a pyramidal mirror or a mirror as the optical deflector. A tenon mirror is used. Of course, the imaging lens portion of the optical scanning lens does not need to be anamorphic, but may be a normal fθ lens having a lens surface rotationally symmetric about the optical axis.

【0018】[0018]

【発明の効果】以上のように、この発明によれば新規な
光走査用レンズおよび光走査装置を提供できる。この発
明は上述の如き構成となっているから、光走査の同期を
とるための同期検知用光センサーの配部における自由度
が増大する。
As described above, according to the present invention, a novel optical scanning lens and optical scanning device can be provided. Since the present invention is configured as described above, the degree of freedom in the arrangement of the optical sensor for synchronization detection for synchronizing optical scanning is increased.

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

【図1】この発明の実施例を説明するための図である。FIG. 1 is a diagram for explaining an embodiment of the present invention.

【図2】別実施例を特徴部分のみ示す図である。FIG. 2 is a view showing another embodiment of the invention, showing only the characteristic portions;

【符号の説明】[Explanation of symbols]

1 光源装置 2 線像結像光学系としてのシリンダーレンズ 3 光偏向器としての回転多面鏡 4 光走査用レンズ 5 光導電性感光体 8 同期検知用 光センサー 41 結像レンズ部分 42 同期検出用レンズ部分 DESCRIPTION OF SYMBOLS 1 Light source device 2 Cylinder lens as a line image imaging optical system 3 Rotating polygon mirror as an optical deflector 4 Optical scanning lens 5 Photoconductive photoreceptor 8 Synchronous detection optical sensor 41 Imaging lens part 42 Synchronous detection lens part

Claims (6)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】光源からの光束を光偏向器により等角速度
的に偏向させ、偏向光束を結像レンズにより被走査面上
に光スポットとして集光せしめて光走査を行なう光走査
装置において、偏向器と被走査面との間の光路上に配備
されるレンズであって、 リニアリティ補正機能を持ち偏向光束を被走査面上に光
スポットとして集光させる結像レンズ部分と、偏向光束
を同期検知用光センサー上に集光させる同期検出用レン
ズ部分とを一体化してなる単体構造であり、上記結像レ
ンズ部分と同期検出用レンズ部分とが、異なる結像特性
を有し、 全体がプラスチックによりモールド成形され、モールド
成形におけるゲートの側で、同期検出用レンズ部分が成
形されることを特徴とする、光走査用レンズ。
An optical scanning device for performing optical scanning by deflecting a light beam from a light source at an equal angular velocity by an optical deflector and condensing the deflected light beam as a light spot on a surface to be scanned by an image forming lens. A lens disposed on the optical path between the scanner and the surface to be scanned, which has a linearity correction function and focuses the deflected light beam as a light spot on the surface to be scanned, and synchronously detects the deflected light beam Is a unitary structure that integrates a synchronization detection lens part that condenses light on the optical sensor for use.The imaging lens part and the synchronization detection lens part have different imaging characteristics, and the whole is made of plastic. An optical scanning lens, which is molded, and a lens part for synchronization detection is molded on a side of a gate in the molding.
【請求項2】請求項1記載の光走査用レンズにおいて、 同期検出用レンズ部分が、同期検知用の偏向光束を、光
走査用の偏向領域から遠ざけるように光軸を調整されて
いることを特徴とする、光走査用レンズ。
2. The optical scanning lens according to claim 1, wherein the synchronization detection lens portion is adjusted in optical axis so that the deflection light beam for synchronization detection is separated from the deflection region for optical scanning. Characterized by the optical scanning lens.
【請求項3】光源装置と、この光源装置からの光束を等
角速度的に偏向させる光偏向器と、この光偏向器による
偏向光束を被走査面上に光スポットとして集光させる光
走査用レンズと、光走査の同期を取るための同期検知用
光センサーとを有し、 光走査用レンズが請求項1または2に記載の光走査用レ
ンズであることを特徴とする、光走査装置。
3. A light source device, an optical deflector for deflecting a light beam from the light source device at a constant angular velocity, and an optical scanning lens for condensing a light beam deflected by the light deflector as a light spot on a surface to be scanned. And an optical sensor for synchronization detection for synchronizing optical scanning, wherein the optical scanning lens is the optical scanning lens according to claim 1 or 2.
【請求項4】光源からの光束を主走査対応方向に長い線
像として結像させ、上記線像の結像位置の近傍に偏向反
射面を持つ光偏向器により等角速度的に偏向させ、偏向
光束を結像レンズにより被走査面上に光スポットとして
集光せしめて光走査を行なう光走査装置において、偏向
器と被走査面との間の光路上に配備されるレンズであっ
て、 主走査対応方向に関してリニアリティ補正機能を持ち、
副走査対応方向に関しては偏向反射面位置と被走査面位
置とを幾何光学的に略共役な関係とする機能を有し、偏
向光束を被走査面上に光スポットとして集光させる結像
レンズ部分と、偏向光束を同期検知用光センサー上に集
光させる同期検出用レンズ部分とを一体化してなる単体
構造であり、上記結像レンズ部分と同期検出用レンズ部
分とが、少なくとも主走査対応方向に関して異なる結像
特性を有し、 全体がプラスチックによりモールド成形され、モールド
成形におけるゲートの側で、同期検出用レンズ部分が成
形されることを特徴とする、光走査用レンズ。
4. A light beam from a light source is formed as a long line image in a direction corresponding to the main scanning, and is deflected at an equal angular velocity by an optical deflector having a deflecting / reflecting surface near an image forming position of the line image. In an optical scanning device for performing optical scanning by condensing a light beam as a light spot on a surface to be scanned by an imaging lens, a lens provided on an optical path between the deflector and the surface to be scanned, comprising: It has a linearity correction function for the corresponding direction,
An imaging lens portion having a function of making the position of the deflecting reflective surface and the position of the scanned surface substantially geometrically conjugate with respect to the sub-scanning corresponding direction, and condensing the deflected light beam as a light spot on the scanned surface. And a synchronous detection lens portion for condensing the deflected light beam on the synchronous detection optical sensor, and has a unitary structure. The imaging lens portion and the synchronous detection lens portion are at least in the main scanning direction. An optical scanning lens, characterized in that it has different imaging characteristics with respect to the above, wherein the whole is molded from plastic, and a lens part for synchronization detection is molded on the side of the gate in the molding.
【請求項5】請求項4記載の光走査用レンズにおいて、 同期検出用レンズ部分が、同期検知用の偏向光束を、光
走査用の偏向領域から遠ざけるように光軸を調整されて
いることを特徴とする、光走査用レンズ。
5. The optical scanning lens according to claim 4, wherein the synchronization detecting lens portion adjusts the optical axis so as to keep the deflection light beam for synchronization detection away from the deflection region for optical scanning. Characterized by the optical scanning lens.
【請求項6】光源装置と、この光源装置からの光束を主
走査対応方向に長い線像として結像せしめる線像結像光
学系と、上記線像の結像位置近傍に偏向反射面を持ち光
束を等角速度的に偏向させる光偏向器と、この光偏向器
による偏向光束を被走査面上に光スポットとして集光さ
せる光走査用レンズと、光走査の同期を取るための同期
検知用光センサーとを有し、 光走査用レンズが請求項4または5に記載の光走査用レ
ンズであることを特徴とする、光走査装置。
6. A light source device, a line image forming optical system for forming a light beam from the light source device as a long line image in the main scanning direction, and a deflecting / reflecting surface near an image forming position of the line image. An optical deflector for deflecting a light beam at an equal angular velocity, an optical scanning lens for condensing a light beam deflected by the optical deflector as a light spot on a surface to be scanned, and a synchronization detecting light for synchronizing optical scanning. An optical scanning device comprising: a sensor; and the optical scanning lens is the optical scanning lens according to claim 4.
JP21236991A 1991-08-23 1991-08-23 Optical scanning lens and optical scanning device Expired - Lifetime JP3073801B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP21236991A JP3073801B2 (en) 1991-08-23 1991-08-23 Optical scanning lens and optical scanning device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP21236991A JP3073801B2 (en) 1991-08-23 1991-08-23 Optical scanning lens and optical scanning device

Publications (2)

Publication Number Publication Date
JPH0553067A JPH0553067A (en) 1993-03-05
JP3073801B2 true JP3073801B2 (en) 2000-08-07

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JP (1) JP3073801B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0783069B2 (en) * 1985-12-19 1995-09-06 第一精工株式会社 Semiconductor device and manufacturing method thereof
JP3031451B2 (en) * 1994-10-27 2000-04-10 シャープ株式会社 Laser scanning device
US5745285A (en) * 1995-10-31 1998-04-28 Raytheon Ti Systems, Inc. Passive scene base calibration system
JP4708629B2 (en) * 2001-09-07 2011-06-22 キヤノン株式会社 Scanning optical device and image forming apparatus using the same
JP2004219770A (en) * 2003-01-15 2004-08-05 Ricoh Co Ltd Optical scanning device and image forming device
JP4745605B2 (en) * 2003-09-24 2011-08-10 キヤノン株式会社 Scanning optical apparatus and image forming apparatus
JP5098566B2 (en) * 2007-10-19 2012-12-12 コニカミノルタビジネステクノロジーズ株式会社 Optical scanning device
JP2009133939A (en) * 2007-11-29 2009-06-18 Kyocera Mita Corp Optical scanner
JP2018146615A (en) * 2017-03-01 2018-09-20 コニカミノルタ株式会社 Image writing device and image forming apparatus

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