JPH11190822A - Scanning lens mount structure for optical scanner - Google Patents
Scanning lens mount structure for optical scannerInfo
- Publication number
- JPH11190822A JPH11190822A JP9357867A JP35786797A JPH11190822A JP H11190822 A JPH11190822 A JP H11190822A JP 9357867 A JP9357867 A JP 9357867A JP 35786797 A JP35786797 A JP 35786797A JP H11190822 A JPH11190822 A JP H11190822A
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- Japan
- Prior art keywords
- scanning
- scanning lens
- lens
- point
- sub
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Mechanical Optical Scanning Systems (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、レーザプリンタ等
に使用される光走査装置の走査レンズ取付構造に関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning lens mounting structure for an optical scanning device used for a laser printer or the like.
【０００２】[0002]
【従来の技術】レーザプリンタ等に用いられる光走査装
置の光学系では、レーザ光を被走査体上に等速走査させ
て線像を形成するために、偏平形状に形成された走査レ
ンズが、一般的に使用されている。そして、高画質を達
成するために、走査位置について大変高い精度がこの走
査レンズには要求され、その要求を満たすためにこの種
の走査レンズの取付構造に関して、従来より種々の提案
が行われている。2. Description of the Related Art In an optical system of an optical scanning device used in a laser printer or the like, a scanning lens formed in a flat shape is used to form a line image by scanning a scanning object at a constant speed with a laser beam. Commonly used. In order to achieve high image quality, the scanning lens is required to have a very high accuracy regarding the scanning position. In order to satisfy the requirement, various proposals have been made with respect to the mounting structure of this type of scanning lens. I have.
【０００３】例えば、特開平６−３００９５２号公報で
は弾性部材を使用したレンズ取付構造が提案されてい
る。For example, Japanese Patent Laid-Open Publication No. Hei 6-300952 proposes a lens mounting structure using an elastic member.
【０００４】つまり、図８に示すように、合成樹脂製の
走査レンズ６０の光線有効部領域以外の部分にリブ６２
を設け、このリブ６２の光軸中心上の底部に、レンズ中
心を光軸中心に位置決めするための基準丸孔６４及び、
光軸中心方向への回転を規制するための長孔６６が設け
られている。That is, as shown in FIG. 8, a rib 62 is formed on a portion of the scanning lens 60 made of a synthetic resin other than the effective ray region.
And a reference circular hole 64 for positioning the lens center at the optical axis center, at the bottom of the rib 62 above the optical axis center,
An elongated hole 66 for restricting rotation in the direction of the optical axis center is provided.
【０００５】一方、光学箱７０には、基準丸孔６４に嵌
合する第１の突起部７２及び、長孔６６に嵌合してその
上方に突出する第２の突起部７４が設けられ、基準丸孔
６４と第１の突起部７２、長孔６６と第２の突起部７４
をそれぞれ嵌合させ、第２の突起部７４の突出した先端
部に弾性部材７６を係止することによって走査レンズ６
０を光学箱７０に固定する。そして以上により、走査レ
ンズ６０の使用環境の変化によって生じる走査レンズ６
０の変形や破損を防止している。On the other hand, the optical box 70 is provided with a first projection 72 fitted in the reference round hole 64 and a second projection 74 fitted in the long hole 66 and projecting upward. Reference round hole 64 and first protrusion 72, long hole 66 and second protrusion 74
Are fitted to each other, and the elastic member 76 is engaged with the protruding distal end of the second projection 74 to thereby form the scanning lens 6.
0 is fixed to the optical box 70. As described above, the scanning lens 6 caused by the change of the use environment of the scanning lens 60
Zero deformation and damage are prevented.
【０００６】また、特開平７−１７５０００号公報では
接着によるレンズ取付構造が提案されている。[0006] Japanese Patent Application Laid-Open No. 7-175000 proposes a lens mounting structure by adhesion.
【０００７】つまり、図９に示すように、レンズ８０を
取り付けるための取付台８１にレンズ支持基準点８２を
有する複数の支持柱８３（図上、一つのみ示す）を設け
て、レンズ８０とこの支持基準点８２とを当接し、レン
ズ８０と支持柱８３の周辺部を接着剤８４により接着す
ることで、接着剤の収縮によるレンズ８０の変位を防止
している。That is, as shown in FIG. 9, a plurality of support columns 83 (only one is shown in the figure) having a lens support reference point 82 are provided on a mount 81 for mounting the lens 80, and By contacting the support reference point 82 and bonding the lens 80 and the periphery of the support column 83 with an adhesive 84, the displacement of the lens 80 due to contraction of the adhesive is prevented.
【０００８】[0008]
【発明が解決しようとする課題】しかし、上記の２つの
先行例のいずれの取付構造の場合においても、プリンタ
等の機器本体が動作することにより、機器内の温度が上
昇し、それに伴って走査レンズに熱膨張が生じる。この
為、図５（ａ）に示すように、走査面と直交する副走査
方向に曲率すなわちパワーを有する走査レンズでは、副
走査方向の光軸ずれを生じるようになる。However, in any of the above two mounting structures, the temperature inside the device rises due to the operation of the device main body such as a printer, and the scanning is accordingly performed. Thermal expansion occurs in the lens. Therefore, as shown in FIG. 5A, an optical axis shift in the sub-scanning direction occurs in a scanning lens having a curvature, that is, power in a sub-scanning direction orthogonal to the scanning surface.
【０００９】従って、上記のような取付構造では、被走
査体上での走査位置が副走査方向にずれるという問題が
あった。Therefore, the above-described mounting structure has a problem that the scanning position on the object to be scanned is shifted in the sub-scanning direction.
【００１０】本発明は、かかる従来技術の有する不都合
に鑑みてなされたもので、温度上昇で走査レンズが熱膨
張を生じるような場合であっても、被走査体上の副走査
方向の走査位置ずれを抑制し、画像品質を向上しうる光
走査装置の走査レンズ取付構造を提供することを目的と
する。The present invention has been made in view of the inconveniences of the prior art, and even when the temperature of the scanning lens causes thermal expansion due to a rise in temperature, the scanning position in the sub-scanning direction on the object to be scanned. An object of the present invention is to provide a scanning lens mounting structure of an optical scanning device capable of suppressing displacement and improving image quality.
【００１１】[0011]
【課題を解決するための手段】請求項１による光学走査
装置の走査レンズ取付構造は、レーザ光源と、前記レー
ザ光源より射出されたレーザ光を偏向走査する光偏向器
と、偏向走査されたレーザ光を被走査体上に結像する走
査レンズと、を有する光走査装置の走査レンズ取付構造
であって、前記走査レンズは副走査方向に沿って曲率を
有し、前記走査レンズの副走査方向の物体側主点と像側
主点との間の線上であって物体側主点からレンズ面頂点
に至る間の点を通り、主走査方向に沿った延長上の位置
で前記走査レンズを支持する取付固定点と、前記取付固
定点廻りの前記走査レンズの回動を停止するように前記
走査レンズを支持する支持点と、を有したことを特徴と
する。According to a first aspect of the present invention, there is provided a scanning lens mounting structure for an optical scanning device, comprising: a laser light source; an optical deflector for deflecting and scanning laser light emitted from the laser light source; A scanning lens for forming an image on a scanning object, the scanning lens having a curvature along a sub-scanning direction, wherein the scanning lens has a curvature along a sub-scanning direction. The scanning lens is supported at a position on the line extending between the object-side principal point and the image-side principal point and a point extending from the object-side principal point to the lens surface vertex and extending along the main scanning direction. And a support point for supporting the scanning lens so as to stop the rotation of the scanning lens about the mounting fixed point.
【００１２】請求項２による光学走査装置の走査レンズ
取付構造は、前記走査レンズがプラスチックレンズであ
ることを特徴とする。According to a second aspect of the present invention, in the scanning lens mounting structure of the optical scanning device, the scanning lens is a plastic lens.
【００１３】請求項３による光学走査装置の走査レンズ
取付構造は、前記支持点が副走査方向に往復動する調整
機構を有することを特徴とする。According to a third aspect of the present invention, there is provided a scanning lens mounting structure for an optical scanning device, wherein the supporting point has an adjusting mechanism for reciprocating in the sub-scanning direction.
【００１４】請求項１に係る光学走査装置の走査レンズ
取付構造の作用を以下に説明する。走査レンズを支持す
る取付固定点は、走査レンズの副走査方向の物体側主点
と像側主点との間の線上であって物体側主点からレンズ
面頂点に至る間の点を通り、主走査方向に沿った延長上
に位置している。そして、温度上昇により走査レンズに
熱膨張が生じると、取付固定点を中心に走査レンズが傾
動するようになっている。The operation of the scanning lens mounting structure of the optical scanning device according to the first aspect will be described below. The mounting fixed point that supports the scanning lens is on a line between the object-side principal point and the image-side principal point in the sub-scanning direction of the scanning lens, and passes through a point between the object-side principal point and the lens surface vertex, It is located on an extension along the main scanning direction. Then, when thermal expansion occurs in the scanning lens due to a rise in temperature, the scanning lens tilts about the mounting and fixing point.
【００１５】ここで走査レンズにおいて主点と呼ばれる
点は、レンズ光軸上の共役点の一つで、角倍率が＋１と
なるような１組の点であり、物体空間に属するものを物
体側主点、像空間に属するものを像側主点と呼ぶ。ま
た、物体側主点を通る入射光線は、入射光と平行に射出
すると共に像側主点を通過することが一般に知られてい
る。Here, the point called the principal point in the scanning lens is one of conjugate points on the optical axis of the lens, and is a set of points having an angular magnification of +1. Those belonging to the principal point and the image space are called image-side principal points. It is generally known that an incident ray passing through the object-side principal point exits in parallel with the incident light and passes through the image-side principal point.
【００１６】この性質を利用すべく、副走査方向に沿っ
て切った断面における物体側主点を中心に走査レンズが
傾動するように、走査レンズの取付構造を構成すれば、
走査レンズが傾動しても、走査レンズに入射して物体側
主点を通った光は、入射光と平行に射出すると共に像側
主点を通過し、射出光は入射光に対して角度成分を持た
ない。このため、被走査体上の入射光との副走査方向に
沿った走査位置のずれ量は、物体側主点と像側主点との
間の距離に対する傾角の正弦成分のみに抑えることが出
来る。In order to utilize this property, if the scanning lens mounting structure is configured so that the scanning lens tilts about the object-side principal point in a cross section cut along the sub-scanning direction,
Even when the scanning lens is tilted, light that has entered the scanning lens and passed through the object-side principal point exits in parallel with the incident light and passes through the image-side principal point, and the emitted light has an angular component with respect to the incident light. Do not have. For this reason, the shift amount of the scanning position along the sub-scanning direction with respect to the incident light on the object to be scanned can be suppressed to only the sine component of the inclination angle with respect to the distance between the object-side principal point and the image-side principal point. .
【００１７】また、走査レンズの物体側主点から若干変
位した位置を中心に走査レンズが傾動した場合、射出光
は角度成分を持つことになるが、被走査体上での副走査
方向に沿った位置ずれ量を補正する方向に射出光が射出
されるならば、被走査体上での副走査方向の走査位置ず
れ量をより小さくすることが出来る。When the scanning lens is tilted about a position slightly displaced from the object-side principal point of the scanning lens, the emitted light has an angular component, but the emitted light has an angle component along the sub-scanning direction on the object to be scanned. If the emitted light is emitted in the direction in which the misalignment is corrected, the scanning misalignment in the sub-scanning direction on the object to be scanned can be further reduced.
【００１８】請求項２に係る光学走査装置の走査レンズ
取付構造の作用を以下に説明する。本請求項も請求項１
と同様の構成を有しており、重複した説明を省略する。
但し、本請求項では走査レンズが熱膨張率が大きいプラ
スチックレンズとされる。つまり、請求項１の構成を有
すれば、従来技術の構成でプラスチックレンズを使用し
た場合と比較して、被走査体上での副走査方向に沿った
走査位置のずれ量を一層小さくすることが出来る。The operation of the scanning lens mounting structure of the optical scanning device according to claim 2 will be described below. This claim is also claim 1
Has the same configuration as that described above, and redundant description will be omitted.
However, in the present invention, the scanning lens is a plastic lens having a large coefficient of thermal expansion. That is, according to the configuration of the first aspect, the shift amount of the scanning position in the sub-scanning direction on the scanned object is further reduced as compared with the case of using the plastic lens in the configuration of the related art. Can be done.
【００１９】請求項３に係る光学走査装置の走査レンズ
取付構造の作用を以下に説明する。本請求項も請求項１
と同様の構成を有しており、重複した説明を省略する。
但し、本請求項では支持点が副走査方向に往復動する調
整機構を有しているので、熱膨張により生じた傾角を小
さくするようにこの調整機構で支持点を調整すること
で、走査線の湾曲を防止することが出来る。The operation of the scanning lens mounting structure of the optical scanning device according to claim 3 will be described below. This claim is also claim 1
Has the same configuration as that described above, and redundant description will be omitted.
However, since the present invention has an adjusting mechanism in which the supporting point reciprocates in the sub-scanning direction, the supporting point is adjusted by this adjusting mechanism so as to reduce the tilt angle caused by the thermal expansion. Can be prevented.
【００２０】[0020]
【発明の実施の形態】以下、図面を参照して本発明の実
施の形態を詳細に説明する。Embodiments of the present invention will be described below in detail with reference to the drawings.
【００２１】図１には、本実施の形態を適用した光走査
装置の概略構成が示されている。この図に示すように、
レーザ光を射出するレーザ光源１２、駆動回転される回
転多面鏡１８を備えた光偏向器２０、レーザ光源１２か
ら射出されたレーザ光を回転多面鏡１８に導くコリメー
タレンズ１４及びシリンダーレンズ１６、回転多面鏡１
８により偏向されたレーザ光が入射される走査レンズ２
２が、それぞれ光学ベース２４に収容されている。FIG. 1 shows a schematic configuration of an optical scanning device to which the present embodiment is applied. As shown in this figure,
A laser light source 12 for emitting laser light, an optical deflector 20 having a rotating polygon mirror 18 driven and rotated, a collimator lens 14 and a cylinder lens 16 for guiding the laser light emitted from the laser light source 12 to the rotating polygon mirror 18, Polygon mirror 1
Scanning lens 2 on which the laser beam deflected by 8 is incident
2 are housed in the optical base 24, respectively.
【００２２】そして、これらレーザ光源１２、コリメー
タレンズ１４、シリンダーレンズ１６、光偏向器２０及
び走査レンズ２２により、光走査装置が構成され、光偏
向器２０の回転多面鏡１８により偏向されたレーザ光を
走査レンズ２２が被走査体２６上へ導くことになる。The laser light source 12, the collimator lens 14, the cylinder lens 16, the optical deflector 20, and the scanning lens 22 constitute an optical scanning device, and the laser light deflected by the rotary polygon mirror 18 of the optical deflector 20. Is guided by the scanning lens 22 onto the object 26 to be scanned.
【００２３】また、図２及び図３に示すように、走査レ
ンズ２２の左右端に対応した光学ベース２４の部分に
は、一対のＶ字状溝３２Ａ、３２Ｂが設けられ、さらに
これら一対のＶ字状溝３２Ａ、３２Ｂの中間部分に支持
柱３４が植設されている。これに対して、走査レンズ２
２の左右端部には、走査レンズ２２と一体に形成された
円柱状突起部３０Ａ、３０Ｂが設けられている。As shown in FIGS. 2 and 3, a pair of V-shaped grooves 32A and 32B are provided in a portion of the optical base 24 corresponding to the left and right ends of the scanning lens 22, and a pair of V-shaped grooves 32A and 32B are provided. A support column 34 is implanted in an intermediate portion between the V-shaped grooves 32A and 32B. On the other hand, the scanning lens 2
2 are provided with columnar projections 30A and 30B integrally formed with the scanning lens 22 at the left and right ends.
【００２４】尚、この走査レンズ２２は、屈折率ｎ＝
１．５１９１３９のプラスチック材料によって構成さ
れ、それぞれ副走査方向Ｙに沿って曲率であるパワーを
有した入射面Ｓ１及び射出面Ｓ２によりその両面が形成
されている。また、本実施の形態では、レーザ光の進行
方向に測った距離を正とし、面の曲率半径を面の表面か
ら曲率中心にむけて測るものとすると、入射面Ｓ１の曲
率半径Ｒ１はＲ１＝−６６．８８（ｍｍ）であり、射出
面Ｓ２の曲率半径Ｒ２はＲ２＝−１７．９０（ｍｍ）で
ある。The scanning lens 22 has a refractive index n =
Both surfaces are formed by an entrance surface S1 and an exit surface S2 which are made of a plastic material of 1.519139 and each have a power having a curvature along the sub-scanning direction Y. Further, in the present embodiment, assuming that the distance measured in the traveling direction of the laser beam is positive and the radius of curvature of the surface is measured from the surface of the surface toward the center of curvature, the radius of curvature R1 of the entrance surface S1 is R1 = −66.88 (mm), and the radius of curvature R2 of the exit surface S2 is R2 = −17.90 (mm).
【００２５】さらに、両端部に切曲片３８Ａ、３８Ｂを
有すると共に中央部に切片３８Ｃを有する弾性部材３６
が、走査レンズ２２の上部に位置するように、ネジ４０
Ａ、４０Ｂ、４０Ｃ、４０Ｄによって光学ベース２４に
ねじ止められている。Further, an elastic member 36 having cut pieces 38A and 38B at both ends and a cut piece 38C at the center.
Are positioned above the scanning lens 22 so that the screws 40
A, 40B, 40C, 40D are screwed to the optical base 24.
【００２６】従って、光学ベース２４のＶ字状溝３２
Ａ、３２Ｂを取付基準となる取付固定点として、走査レ
ンズ２２の円柱状突起部３０Ａ、３０Ｂが支持され、光
学ベース２４に設けられた支持柱３４を支持基準となる
支持点として、走査レンズ２２の底面が支持される。Therefore, the V-shaped groove 32 of the optical base 24
A, 32B are used as mounting fixing points serving as mounting references, the columnar projections 30A, 30B of the scanning lens 22 are supported, and the supporting columns 34 provided on the optical base 24 are used as supporting points serving as supporting references. Is supported.
【００２７】そして、弾性部材３６に設けられた切曲片
３８Ａ、３８Ｂが、走査レンズ２２の円柱状突起部３０
Ａ、３０ＢをＶ字状溝３２Ａ、３２Ｂに弾性的に押圧
し、弾性部材３６に設けられた切片３８Ｃが、走査レン
ズ２２を光学ベース２４に設けられた支持性３４に弾性
的に押圧する。The cut pieces 38A and 38B provided on the elastic member 36 are connected to the cylindrical projections 30 of the scanning lens 22.
A and 30B are elastically pressed against the V-shaped grooves 32A and 32B, and the section 38C provided on the elastic member 36 elastically presses the scanning lens 22 against the support 34 provided on the optical base 24.
【００２８】ここでは、本実施の形態で使用する走査レ
ンズ２２の円柱状突起部３０Ａ、３０Ｂは、Ｖ字状溝３
２Ａ、３２Ｂによって、レーザ光の走査面内にありかつ
走査レンズ２２の副走査方向Ｙに沿って切った断面にお
ける物体側主点Ｈを通り、主走査方向Ｘに沿った延長上
の位置に配置されている。また、本実施の形態の支持柱
３４は、円柱状突起部３０Ａ、３０Ｂ廻りの走査レンズ
２２の回動を停止するべく、走査レンズ２２の入射面Ｓ
１近傍の底面を支持するように設けられている。Here, the columnar projections 30A and 30B of the scanning lens 22 used in the present embodiment are
By 2A and 32B, they are located on the extension plane along the main scanning direction X, passing through the object side principal point H in the cross section taken along the sub scanning direction Y of the scanning lens 22 within the scanning plane of the laser beam. Have been. In addition, the support column 34 of the present embodiment has an incident surface S of the scanning lens 22 to stop the rotation of the scanning lens 22 around the columnar projections 30A and 30B.
1 is provided to support the bottom surface in the vicinity.
【００２９】次に、本実施の形態に係る光走査装置の温
度上昇に伴って走査レンズ２２が熱膨張した場合の副走
査方向Ｙに沿った走査位置ずれについて、図４に基づき
従来例と対比して具体的に説明する。Next, the scanning position shift along the sub-scanning direction Y when the scanning lens 22 thermally expands due to the temperature rise of the optical scanning device according to the present embodiment will be compared with the conventional example based on FIG. This will be described specifically.
【００３０】図４には、Ａ４紙の短辺の中央部を０ｍｍ
とした−１０５〜＋１０５ｍｍの走査範囲内で、１０°
Ｃ、２０°Ｃ、３０°Ｃの温度上昇時における本実施の
形態及び従来例の走査位置のずれ量δが示されている。
つまり、この図には、被走査体２６上での副走査方向Ｙ
に沿った本実施の形態の走査位置のずれ量δ（ｍｍ）及
び、同じく従来例の走査位置のずれ量δ（ｍｍ）が示さ
れている。FIG. 4 shows that the center of the short side of A4 paper is 0 mm.
10 ° within a scanning range of −105 to +105 mm
The shift amounts δ of the scanning positions of the present embodiment and the conventional example when the temperature rises at C, 20 ° C., and 30 ° C. are shown.
That is, in this figure, the sub-scanning direction Y
, The shift amount δ (mm) of the scanning position of the present embodiment along with the shift amount δ (mm) of the scanning position of the conventional example.
【００３１】例えば、３０°Ｃ上昇時における副走査方
向Ｙに沿った走査位置の従来例及び本実施の形態のずれ
量δをＡ４紙の短辺の中央部（０ｍｍ位置）で比較する
と、従来例では０．０３５ｍｍであるのに対して、本実
施の形態では０．００５８ｍｍであり、副走査方向Ｙに
沿った走査位置のずれ量δが大幅に低減出来ているのが
わかる。For example, comparing the shift amount δ between the conventional example and the present embodiment at the scanning position along the sub-scanning direction Y when the temperature rises by 30 ° C. at the center (0 mm position) of the short side of A4 paper, In the example, it is 0.035 mm, but in the present embodiment, it is 0.0058 mm. It can be seen that the shift amount δ of the scanning position along the sub-scanning direction Y can be significantly reduced.
【００３２】つまりこのように、走査レンズ２２の取付
固定点を、走査面内にありかつ走査レンズ２２の副走査
方向Ｙに沿って切った断面における物体側主点Ｈを通
り、主走査方向Ｘに沿った延長上の位置に設けることに
より、被走査体２６上の副走査方向Ｙに沿った走査位置
ずれをほとんど生じないように出来る。That is, as described above, the fixing point of the scanning lens 22 passes through the object side principal point H in the cross section of the scanning lens 22 along the sub-scanning direction Y within the scanning plane and passes through the main scanning direction X Is provided at an extended position along the scanning line 26, the scanning position shift along the sub-scanning direction Y on the scanned body 26 can be substantially prevented.
【００３３】次に、図５に基づき本実施の形態によるず
れ量δの低減のメカニズムを説明する。この図は本発明
に係わる光走査光学系の副走査方向Ｙの断面図であり、
走査レンズ２２の光軸を一点鎖線、光線を実線、走査面
を点線で示してある。Next, a mechanism for reducing the shift amount δ according to the present embodiment will be described with reference to FIG. This figure is a sectional view of the optical scanning optical system according to the present invention in the sub-scanning direction Y,
The optical axis of the scanning lens 22 is shown by a dashed line, the light beam is shown by a solid line, and the scanning surface is shown by a dotted line.
【００３４】図５（ｂ）に示すように、走査レンズ２２
の取付固定点は、レーザ光が走査される走査面内にあり
かつ走査レンズ２２の走査面に直交する副走査方向Ｙに
沿って切った断面における物体側主点Ｈを通り、主走査
方向Ｘに沿った延長上の位置に設けられている。そし
て、温度上昇により走査レンズ２２に熱膨張が生じる
と、取付固定点を中心に走査レンズ２２が傾動するよう
になる。As shown in FIG. 5B, the scanning lens 22
Is located in the scanning plane where the laser light is scanned and passes through the object-side principal point H in a section taken along the sub-scanning direction Y orthogonal to the scanning plane of the scanning lens 22 and passes through the main scanning direction X Is provided at a position on the extension along. Then, when the thermal expansion occurs in the scanning lens 22 due to the temperature rise, the scanning lens 22 tilts about the fixing point.
【００３５】つまり、副走査方向Ｙに沿って切った断面
における物体側主点Ｈを中心に走査レンズ２２が傾動す
るように、走査レンズ２２の取付構造が構成されている
ので、走査レンズ２２が傾動しても、走査レンズ２２に
入射して物体側主点Ｈを通った光は、入射光と平行に射
出しすると共に像側主点Ｈ1 を通過して、射出光は入射
光に対して角度成分を持たない。That is, the mounting structure of the scanning lens 22 is configured such that the scanning lens 22 is tilted about the object-side principal point H in a cross section cut along the sub-scanning direction Y. be tilted, the light passing through the object side principal point H is incident on the scanning lens 22, passes through the image-side principal point H 1 as well as by injection parallel to the incident light, emitted light with respect to incident light Has no angle component.
【００３６】従って、被走査体上の入射光との副走査方
向Ｙに沿った走査位置のずれ量δを、物体側主点Ｈと像
側主点Ｈ1 との間の距離ＨＨ1 に対する傾角θの正弦成
分であるＨＨ1 ×ｓｉｎθのみに抑えることが出来る。Accordingly, the shift amount δ of the scanning position in the sub-scanning direction Y with respect to the incident light on the object to be scanned is determined by the inclination angle with respect to the distance HH 1 between the object-side principal point H and the image-side principal point H 1. It can be suppressed to only HH 1 × sin θ which is a sine component of θ.
【００３７】以上ここまでは、傾動中心となる取付固定
点が物体側主点Ｈに位置する場合について説明してきた
が、走査レンズ２２の物体側主点Ｈから若干変位した位
置を中心に傾動した場合にも、図６に示すように、被走
査体２６上での副走査方向Ｙに沿った走査位置ずれを小
さく抑える事が出来る範囲が存在する。Up to this point, a case has been described in which the mounting fixed point serving as the tilt center is located at the object-side principal point H. However, the scanning lens 22 is tilted about a position slightly displaced from the object-side principal point H. In this case as well, as shown in FIG. 6, there is a range in which the scanning position shift along the sub-scanning direction Y on the scanned body 26 can be suppressed to a small value.
【００３８】つまり、図６には、入射面Ｓ１から傾動中
心位置までの光線の進行方向に沿った距離（ｍｍ）を横
軸にとり、副走査方向Ｙ位置のずれ量δ（ｍｍ）を縦軸
にとったときにおける、各傾動中心位置における３０°
Ｃ上昇時のＡ４紙の短辺の中央部である走査中央（０ｍ
ｍ）及び走査端（−１０５ｍｍ及び＋１０５ｍｍの位
置）でのずれ量δが、示されている。そして、この図に
示すグラフから、物体側主点Ｈと射出面Ｓ２の表面との
間に傾動中心を位置させることで、０．００５ｍｍ程度
に位置ずれを小さく出来るのがわかる。That is, in FIG. 6, the horizontal axis represents the distance (mm) along the traveling direction of the light beam from the incident surface S1 to the tilt center position, and the vertical axis represents the shift amount δ (mm) of the Y position in the sub-scanning direction. 30 ° at each tilt center position
Scan center (0 m) which is the center of the short side of A4 paper when C rises
m) and the shift amount δ at the scanning end (at the positions of −105 mm and +105 mm) are shown. From the graph shown in this figure, it can be seen that the positional deviation can be reduced to about 0.005 mm by positioning the tilt center between the object-side principal point H and the surface of the exit surface S2.
【００３９】すなわち、図５（ｃ）に示すように、走査
レンズ２２の物体側主点Ｈから若干変位した位置Ｐを中
心に傾動した場合、射出光は角度成分を持つことにな
る。しかし、物体側主点Ｈと射出面Ｓ２の表面との間に
傾動中心を位置させることで、被走査体２６上での副走
査方向Ｙに沿った走査位置のずれ量δを補正する方向に
射出光が射出され、走査位置のずれ量δをより小さくす
ることが出来る。That is, as shown in FIG. 5C, when the scanning lens 22 is tilted about a position P slightly displaced from the object-side principal point H of the scanning lens 22, the emitted light has an angular component. However, by locating the tilting center between the object-side principal point H and the surface of the exit surface S2, the deviation of the scanning position δ along the sub-scanning direction Y on the scanned object 26 is corrected. The emitted light is emitted, and the shift amount δ of the scanning position can be further reduced.
【００４０】以上より、走査レンズ２２の取付固定点
は、レーザ光が走査される走査面内にありかつ走査レン
ズ２２の走査面に直交する副走査方向Ｙに沿って切った
断面における物体側主点Ｈと像側主点Ｈ1 との間の線上
であって物体側主点Ｈからレンズ面頂点が位置する射出
面Ｓ２の表面に至る間の点を通り、主走査方向Ｘに沿っ
た延長上の位置に設ければ良いことなる。As described above, the mounting fixed point of the scanning lens 22 is located on the object side main surface in the cross section taken along the sub-scanning direction Y which is within the scanning plane on which the laser beam is scanned and is orthogonal to the scanning plane of the scanning lens 22. An extension along the main scanning direction X passing through a point on the line between the point H and the image-side principal point H 1 and from the object-side principal point H to the surface of the exit surface S2 where the lens surface vertex is located. What is necessary is just to provide in the upper position.
【００４１】尚、本実施の形態はプラスチック製レンズ
のように熱膨張率が比較的大である場合に好適である
が、ガラス製のレンズに対しても、本発明が適用できる
ことは言うまでもない。The present embodiment is suitable for a case where the coefficient of thermal expansion is relatively large like a plastic lens, but it goes without saying that the present invention can also be applied to a glass lens.
【００４２】また、上記実施の形態では、図４及び図６
に示すように温度上昇時に走査位置の中央と左右端で走
査位置のずれ量δが異なり、被走査体２６上での走査線
の湾曲が生じることがわかる。In the above-described embodiment, FIGS.
As shown in FIG. 7, when the temperature rises, the shift amount δ of the scanning position differs between the center of the scanning position and the left and right ends, and it can be seen that the scanning line curves on the scanned body 26.
【００４３】そこで、支持柱３４の替わりに、図７に示
すように精密調整用スクリュ４２を用いて副走査方向Ｙ
に往復動する調整機構とする。そして、この精密調整用
スクリュ４２の調整機構による調整で、熱膨張によって
生じた走査レンズ２２の傾動を減少させ、走査レンズ２
２の光軸が走査平面と平行になるように走査レンズ２２
の姿勢を調整することで、走査線の湾曲を補正すること
が出来る。Therefore, instead of the support column 34, a fine adjustment screw 42 is used as shown in FIG.
An adjustment mechanism that reciprocates at The adjustment of the fine adjustment screw 42 by the adjustment mechanism reduces the tilt of the scanning lens 22 caused by thermal expansion,
Scanning lens 22 so that the optical axis 2 is parallel to the scanning plane.
By adjusting the posture, the curvature of the scanning line can be corrected.
【００４４】[0044]
【発明の効果】以上説明してきたように請求項１及び請
求項２記載の発明は上記の構成としたため、温度上昇に
より走査レンズに熱膨張が生じても、被走査体上の副走
査方向の走査位置ずれがほとんど発生せず、結果として
画像品質を向上することが出来るという効果を奏する。As described above, the first and second aspects of the present invention have the above-described structure. Therefore, even if a thermal expansion occurs in the scanning lens due to a temperature rise, the scanning lens in the sub-scanning direction on the object to be scanned. Scanning position shift hardly occurs, and as a result, an effect of improving image quality can be obtained.
【００４５】また、請求項３記載の発明は上記の構成と
したため、被走査体上の湾曲を補正することが出来、結
果として、画像品質を向上することが出来るという効果
を奏する。The third aspect of the present invention is configured as described above, so that the curvature on the object to be scanned can be corrected, and as a result, the image quality can be improved.
【図１】本実施の形態の走査レンズ取付構造が適用され
た光走査装置の概略構成図である。FIG. 1 is a schematic configuration diagram of an optical scanning device to which a scanning lens mounting structure according to an embodiment is applied.
【図２】本実施の形態の走査レンズ取付構造の要部を示
した分解斜視図である。FIG. 2 is an exploded perspective view showing a main part of the scanning lens mounting structure according to the embodiment.
【図３】本実施の形態の走査レンズ取付構造の要部を示
した断面図である。FIG. 3 is a cross-sectional view showing a main part of the scanning lens mounting structure according to the embodiment.
【図４】本実施の形態の温度上昇量と被走査体上での副
走査方向に沿った走査位置のずれ量との関係を表したグ
ラフを示す図である。FIG. 4 is a graph showing a relationship between a temperature rise amount and a shift amount of a scanning position along a sub-scanning direction on an object to be scanned in the present embodiment.
【図５】走査レンズが熱膨張した際の走査レンズを通っ
て被走査体上に至る光線の軌跡を対比させて示す図であ
って、（ａ）は従来例の概念図であり、（ｂ）、（ｃ）
は本実施の形態の概念図である。5A and 5B are diagrams showing, in contrast, the trajectories of light rays that reach the scanned object through the scanning lens when the scanning lens thermally expands, wherein FIG. 5A is a conceptual diagram of a conventional example, and FIG. ), (C)
Is a conceptual diagram of the present embodiment.
【図６】走査レンズの取付固定点の位置と被走査体上で
の副走査方向に沿った走査位置のずれ量との関係を表し
たグラフを示す図である。FIG. 6 is a graph showing a relationship between a position of a fixing point of a scanning lens and a shift amount of a scanning position along a sub-scanning direction on an object to be scanned.
【図７】他の実施の形態の走査レンズ取付構造要部の断
面図である。FIG. 7 is a cross-sectional view of a main part of a scanning lens mounting structure according to another embodiment.
【図８】第１の従来例を示す図である。FIG. 8 is a diagram showing a first conventional example.
【図９】第２の従来例を示す図である。FIG. 9 is a diagram showing a second conventional example.
２２ 走査レンズ ３０Ａ、３０Ｂ 円柱状突起部 ３２Ａ、３２Ｂ Ｖ字状溝 ３４ 支持柱 ４２ 精密調整用スクリュ 22 Scanning lens 30A, 30B Cylindrical projection 32A, 32B V-shaped groove 34 Support pillar 42 Precision adjustment screw
Claims (3)
されたレーザ光を偏向走査する光偏向器と、偏向走査さ
れたレーザ光を被走査体上に結像する走査レンズと、を
有する光走査装置の走査レンズ取付構造であって、 前記走査レンズは副走査方向に沿って曲率を有し、 前記走査レンズの副走査方向の物体側主点と像側主点と
の間の線上であって物体側主点からレンズ面頂点に至る
間の点を通り、主走査方向に沿った延長上の位置で前記
走査レンズを支持する取付固定点と、 前記取付固定点廻りの前記走査レンズの回動を停止する
ように前記走査レンズを支持する支持点と、 を有したことを特徴とする光走査装置の走査レンズ取付
構造。1. An optical scanner comprising: a laser light source; an optical deflector that deflects and scans the laser light emitted from the laser light source; and a scanning lens that forms an image of the deflected and scanned laser light on an object to be scanned. A scanning lens mounting structure of the device, wherein the scanning lens has a curvature along a sub-scanning direction, and is on a line between an object-side principal point and an image-side principal point in the sub-scanning direction of the scanning lens. A fixing point for supporting the scanning lens at a position on the extension along the main scanning direction passing through a point from the object-side principal point to the vertex of the lens surface; and a rotation of the scanning lens around the fixing point. And a support point for supporting the scanning lens so as to stop the scanning lens.
あることを特徴とする請求項１記載の光走査装置の走査
レンズ取付構造。2. The scanning lens mounting structure according to claim 1, wherein the scanning lens is a plastic lens.
整機構を有することを特徴とする請求項１記載の光走査
装置の走査レンズ取付構造。3. The scanning lens mounting structure according to claim 1, further comprising an adjusting mechanism for reciprocating the support point in the sub-scanning direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35786797A JP3656383B2 (en) | 1997-12-25 | 1997-12-25 | Scanning lens mounting structure of optical scanning device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35786797A JP3656383B2 (en) | 1997-12-25 | 1997-12-25 | Scanning lens mounting structure of optical scanning device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11190822A true JPH11190822A (en) | 1999-07-13 |
| JP3656383B2 JP3656383B2 (en) | 2005-06-08 |
Family
ID=18456348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35786797A Expired - Fee Related JP3656383B2 (en) | 1997-12-25 | 1997-12-25 | Scanning lens mounting structure of optical scanning device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3656383B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6657760B2 (en) | 2000-01-14 | 2003-12-02 | Canon Kabushiki Kaisha | Image scanning apparatus |
| JP2010008761A (en) * | 2008-06-27 | 2010-01-14 | Sharp Corp | Optical scanner and image-forming device equipped with the same |
| JP2011033735A (en) * | 2009-07-30 | 2011-02-17 | Kyocera Mita Corp | Optical apparatus and image forming apparatus |
| US8004552B2 (en) | 2008-06-27 | 2011-08-23 | Sharp Kabushiki Kaisha | Optical scanning device and image forming apparatus |
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| JPS61185711A (en) * | 1985-02-14 | 1986-08-19 | Matsushita Electric Ind Co Ltd | optical scanning device |
| JPH05127002A (en) * | 1991-10-31 | 1993-05-25 | Ricoh Co Ltd | Plastic lens and lens optical system |
| JPH06300952A (en) * | 1993-04-13 | 1994-10-28 | Canon Inc | Scanning lens holding structure |
| JPH07175000A (en) * | 1993-12-20 | 1995-07-14 | Fuji Xerox Co Ltd | Lens mounting structure |
| JPH09218367A (en) * | 1996-02-08 | 1997-08-19 | Asahi Optical Co Ltd | Scanning optical device |
| JPH11142758A (en) * | 1997-11-05 | 1999-05-28 | Ricoh Co Ltd | Optical scanning device |
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1997
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61185711A (en) * | 1985-02-14 | 1986-08-19 | Matsushita Electric Ind Co Ltd | optical scanning device |
| JPH05127002A (en) * | 1991-10-31 | 1993-05-25 | Ricoh Co Ltd | Plastic lens and lens optical system |
| JPH06300952A (en) * | 1993-04-13 | 1994-10-28 | Canon Inc | Scanning lens holding structure |
| JPH07175000A (en) * | 1993-12-20 | 1995-07-14 | Fuji Xerox Co Ltd | Lens mounting structure |
| JPH09218367A (en) * | 1996-02-08 | 1997-08-19 | Asahi Optical Co Ltd | Scanning optical device |
| JPH11142758A (en) * | 1997-11-05 | 1999-05-28 | Ricoh Co Ltd | Optical scanning device |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6657760B2 (en) | 2000-01-14 | 2003-12-02 | Canon Kabushiki Kaisha | Image scanning apparatus |
| JP2010008761A (en) * | 2008-06-27 | 2010-01-14 | Sharp Corp | Optical scanner and image-forming device equipped with the same |
| US8004552B2 (en) | 2008-06-27 | 2011-08-23 | Sharp Kabushiki Kaisha | Optical scanning device and image forming apparatus |
| JP2011033735A (en) * | 2009-07-30 | 2011-02-17 | Kyocera Mita Corp | Optical apparatus and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3656383B2 (en) | 2005-06-08 |
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