JP4023941B2

JP4023941B2 - Optical scanning device

Info

Publication number: JP4023941B2
Application number: JP03937899A
Authority: JP
Inventors: 友哉大杉
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1999-02-18
Filing date: 1999-02-18
Publication date: 2007-12-19
Anticipated expiration: 2019-02-18
Also published as: JP2000241735A

Description

【０００１】
【発明の属する技術分野】
本発明は、レーザを用いた光走査装置に関し、デジタル複写機、レーザＦＡＸ、レーザプリンタ等に適用し得る光走査装置に関する。
【０００２】
【従来の技術】
近年、レーザプリンタ等において画像形成の高速化と画像の高精細化の要求が高まってきている。この高速化、高精細化を実現するには、レーザビームにより走査しながら感光体上に静電潜像の書き込みを行う光走査における走査速度の高速化、書き込まれた画像の高分解能化を図ることが具体的な解決課題の１つである。
高速化についていうと、レーザビームの走査は、回転多面鏡を回転させることにより行うので、回転多面鏡の回転の高速化によりその実現を図ることが可能であるが、高速回転させると回転多面鏡のダイナミックバランスに起因する振動が大きくなり、また本体駆動系のモータやギヤ等の駆動要素の回転振動等も加わることになり、光走査装置内の光学素子が振動し、感光体面上の光の走査位置のずれが生じ、画像の濃度ムラを発生させるので画質が低下し、高精細化に反するという問題が生じる。
【０００３】
特に、光走査装置内の折り返しミラーは、走査範囲をカバーするミラー面を必要とするので長尺であることが多く、かつその支持に際し支持部材により走査光が遮られないように配慮する結果としてミラー両端を支持する場合が多い。このようなことから、ミラーの中央部に振幅の大きな振動が発生しやすい。
図５はこうした従来の光走査装置の構成の１例を示す。また、その光走査装置を構成する光学素子の配置を図６に示す。
図５及び図６に示すように、この光走査装置は、回転多面鏡５１、回転多面鏡駆動モータ５２、トロイダルレンズ５３、透過ガラス５４，５７、第１折り返しミラー５５、第２折り返しミラー５６、感光体５８、ｆθミラー５９、光学箱６１、半導体レーザユニット６２、折り返しミラー６３、シリンドリカルレンズ６４、同期検知板６５、折り返しミラー６６を構成要素として備える。
装置におけるレーザビームの光路を図６に基づき概略説明する。先ず、半導体レーザユニット６２に在る光源より射出されたレーザビームは、回転多面鏡５１により偏向され、透過ガラス５４を通り、光軸６０に沿いｆθミラー５９に向かい、第１折り返しミラー５５、トロイダルレンズ５３、第２折り返しミラー５６、透過ガラス５７を経て感光体５８上に結像される。
【０００４】
図５及び図６に示す従来の光走査装置が構成要素として用いている折り返しミラーについて図７に基づきより詳細に説明する。図７に示される折り返しミラー支持部は、従来構成の典型例を示すもので、折り返しミラー７１は、レーザビームの画像書込利用範囲７１ｗのビームを遮らないように両端部付近をばね７３により支持部材７２₁及び７２₂に押しつけられており（図示していないが支持部材７２₁の対向位置にもばねが存在する）、これにより反射面の傾きが決められている。
この部分について、図７を矢印Ａの方向から見た図８にその状態が示される。反射面の傾きを精度よく保つために支持部材７２₁、７２₂のミラーへの接触面は小さくして点接触に近い形としている。こうした支持状態にあるミラーを図７のＢの方向から見ると図９のような両側自由端支持のはりに近い形となる。光走査装置内の折り返しミラーは長尺であることが多く、このような両側自由端支持の形では非常に振動しやすく、図９に示すようなモードで振動し（図中、ミラー７１の最大振幅をＳ１で表す）、上記したように画質の低下という問題が生じる。
この問題に対し、ミラーの剛性を高くするためにミラーの板厚を大きくしたり、ミラーの裏面に板ガラスや防振材を貼り付けるなどの対策をした例もあるが、かなりのコストアップとなる。
【０００５】
【発明が解決しようとする課題】
本発明は、従来の光走査装置の高速化において生じる上述した問題点に鑑みてなされたものであって、その目的は、レーザビームの走査範囲をカバーする長尺のミラー面の両端を支持する構造をとる折り返しミラーの中央部に発生しやすい振幅の大きな振動を減少或いは抑制させるようにし、高速動作が可能な光走査装置を提供する。
【０００６】
【課題を解決するための手段】
請求項１の発明は、光束を偏向する光偏向器と、該光偏向器により偏向され生じる走査光束を反射するミラーを有する光走査装置において、前記ミラーは、画像を担った走査光束が投射される有効利用範囲に加え主走査方向に余分な長さ部分を有するとともに、前記有効利用範囲に近接する走査方向両側の箇所及び前記両側の箇所より外側の前記余分な長さ部分の少なくとも３箇所の支持箇所で、支持部材と該支持部材に対し前記ミラーを押し付ける押し付け部材とを、前記ミラーを介して互いに対向配置したことを特徴とするものである。
【０００７】
請求項２の発明は、請求項１記載の光走査装置において、前記余分な長さ部分を前記有効利用範囲の走査方向両側に有することを特徴とするものである。
【０００８】
請求項３の発明は、請求項１又は２記載の光走査装置において、前記支持箇所の中で前記ミラーの反射面の傾きを保持するために機能する箇所を除いた他の支持箇所の少なくとも１つが前記ミラーの反射面に接する弾性体を介して支持されることを特徴とするものである。
【０００９】
請求項４の発明は、請求項１ないし３のいずれかに記載の光走査装置において、前記支持箇所の中で前記ミラーの反射面の傾きを保持するために機能する箇所を除いた他の支持箇所の少なくとも１つが防振材を介して支持されることを特徴とするものである。
【００１０】
請求項５の発明は、請求項１ないし４のいずれかに記載の光走査装置において、前記ミラーを支持部材により支持するためにミラーの反射面を各支持箇所の支持部材に押しつけるばね部材を設けることを特徴とするものである。
【００１１】
請求項６の発明は、請求項５記載の光走査装置において、前記ばね部材を複数の支持箇所に共通に働く単一の部材とすることを特徴とするものである。
【００１２】
【発明の実施の形態】
本発明による光走査装置を添付する図面とともに示す以下の実施例に基づき説明する。なお、光走査装置全体の基本的な構成は、上記で図５及び図６に従来技術として示したものと同様の構成を採ることにより実施しうるので、この点については記載を省略することとし、本発明に特有の構成部分をもつ折り返しミラー部についてのみ以下にその実施例を示す。
【００１３】
図１に本発明による光走査装置を構成する折り返しミラーの実施例を示す。
図１に示す実施例においては、折り返しミラー１を画像書込利用範囲１ｗ（この範囲に投射される走査光束は感光体へ書き込まれる画像を担い反射後に画像を形成するために有効に利用される）に対して走査光の主走査方向に所定長長くし、画像書込利用範囲１ｗに近い所に支持部材２₂，２₃、を、また、画像書込利用範囲１ｗから離れたミラー１の端部に近いところに支持部材２₁，２₄を設ける。図示していないが、これら４つの支持部材に対向するミラーの裏面にはそれぞれ板ばね（図１では、板ばね３₁のみ示される）を備えており、これらの板ばねによりミラー１は各支持部材２₁〜２₄に押しつけられている。ここでは支持部材２₃が上下の２点で折り返しミラー１を受ける形となっているが、これは折り返しミラー１の傾きを所定量に保つためのものであり、他の方法でも良い。例えば支持部析２₂のミラー受け面の高さ方向の位置を支持部析２₁とずらすなどすれば、支持部析２₃は上下に分ける必要はない。
【００１４】
図１を矢印Ｃの方向から見ると、図２のように簡略的に表される。（ミラー１の最大振幅をＳ２で表す）このように、従来の構成例を示す図９と比べ、主走査方向の支持点を増やすことにより折り返しミラーの振動を低減（Ｓ１＞Ｓ２）することができる。また各支持部材２₁〜２₄の間を適当な距離にすることにより、折り返しミラー１の固有振動数をある程度自由に決めることができ、例えばレーザプリンタ本体のメインモータの駆動周波数とこのミラーの固有振動数とを意図的にずらすなどのことが可能となり、単にミラーの剛性を上げるのではなく、効率よくミラーの振動を低減することができる。
【００１５】
なお、図１ではミラーの画像書込利用範囲１ｗ外の部分の主走査方向走査上流側及び走査下流側の両方について、光の主走査方向に２ケ所の支持点を設けた例を示したが、本発明において、画像書込利用範囲１ｗに近い所に設けた支持部材２₂，２₃以外に設けた支持部材は必ずしも２つである必要はなく、４つより多くても良いし、また配置スペースの関係でミラーの長さを十分に取れない場合に１つでも良く、例えば図１で言えば、支持部材２₄をなくし、この場合にも図７の従来例に比べればミラーの振動は低減できる。
【００１６】
図３に本発明による他の実施例の構成を示す。
本実施例は、図１に示す実施例と基本構成において共通するが、相違はミラーの両端部に設けた支持部材２₁及び２₄にゴムクッション４₁及び４₄を設けた点にある。ミラー１は板ばね（図１では、板ばね３₁のみ示される）によりこのゴムクッション４₁，４₄及び支持部材２₂，２₃に押しつけられている。ミラーの傾きは支持部材２₂及び２₃に設けられた３点の受け面により決まり、ゴムクッション４₁，４₄に対向するミラーの裏面にはそれぞれ板ばねを備えており、ミラー１の平面度を悪化させないように支持している。
また、このゴムクッション４₁，４₄を防振性の高いゴムとすると良い。
なお、図３はあくまでも構成の一例であり、本発明において支持部材及びゴムクッションの数や位置は図３の通りである必要はない。すなわち、画像書込利用範囲１ｗ外の部分の主走査方向走査上流側及び走査下流側の両方に支持部材を全体で少なくとも３点設け、その内の２点にはゴムクッションを設けないようにすることが必要条件であり、この必要条件を満足しさえすれば、支持部材及びゴムクッションの数や位置の条件を変更して実施しても良い。
【００１７】
図４に本発明による他の実施例の構成を示す。
図４においては、ミラー１は反射面の裏面が見えており、一対のばねからなる板ばね３₁及び３₂の合計して４つのばね部に対向するミラー面にはそれぞれ支持部材（図４では、支持部材２₂のみ示される）が設けられている。この板ばねを採用することにより部品数が少なくなり、構成及び組み付け作業が簡素化され、作業性も良い。
【００１８】
【発明の効果】
請求項１，２の発明によれば、画像書き込みに用いる走査光束が投射されるミラーの有効利用範囲に近接する走査方向両側の箇所及び前記両側の箇所より外側の前記余分な長さ部分の少なくとも３箇所の支持箇所で、支持部材と該支持部材に対し前記ミラーを押し付ける押し付け部材とを、前記ミラーを介して互いに対向配置したという簡単な構成により、この種の光走査装置の長尺ミラーに生じていたる振動の振幅を低減することができ、画像書き込みの性能を向上させることができる。
【００１９】
請求項３の発明によれば、反射面に接する弾性体を介してミラーを支持することにより、反射面の平面度を悪化させることなく、請求項１，２の作用効果を得ることが出来る。
【００２０】
請求項４の発明によれば、請求項１ないし３の発明による効果に加え、防振材により振動を抑制することによりさらに効率よくミラーの振動を低減するができる。
【００２１】
請求項５，６の発明により、ミラーを支持するための具体化手段として簡単な構成で、確実に動作する手段が提供できる。また、請求項６の発明によれば、部品数が少なくなり、組み付け作業性も良い。
【図面の簡単な説明】
【図１】本発明による光走査装置を構成する折り返しミラーの実施例を示す。
【図２】図１に示す折り返しミラーを矢印Ｃの方向から見た振動の様子を示す簡略図である。
【図３】本発明による光走査装置を構成する折り返しミラーの他の実施例の構成を示す。
【図４】本発明による光走査装置を構成する折り返しミラーのさらに他の実施例の構成を示す。
【図５】従来の光走査装置の構成の１例を示す。
【図６】図５に示す光走査装置を構成する光学素子の配置を示す。
【図７】従来の光走査装置が構成要素とする折り返しミラーの１例を示す。
【図８】図７に示す折り返しミラーを矢印Ａの方向から見た図である。
【図９】図７に示す折り返しミラーを矢印Ｂの方向から見た振動の様子を示す簡略図である。
【符号の説明】
１…折り返しミラー、１ｗ…画像書込利用範囲、
２₁〜２₄…支持部材、３₁，３₂…板ばね、
４₁，４₄…ゴムクッション、
５１…回転多面鏡、５２…回転多面鏡駆動モータ、
５３…トロイダルレンズ、５４…透過ガラス、
５５…第１折り返しミラー、５６…第２折り返しミラー、
５７…透過ガラス、５８… 感光体、５９…ｆθミラー、
６０…光軸、６１…光学箱、
６２…半導体レーザユニット、６３…折り返しミラー、
６４，６６…シリンドリカルレンズ、６５…同期検知板、
７１…折り返しミラー、７１ｗ…画像書込利用範囲、
７２₁、７２₂…支持部材、
７３…板ばね、７４…ねじ、
７５…入射光、７６…反射光。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical scanning device using a laser, and relates to an optical scanning device applicable to a digital copying machine, a laser FAX, a laser printer, and the like.
[0002]
[Prior art]
In recent years, there has been an increasing demand for high-speed image formation and high-definition images in laser printers and the like. In order to realize this high speed and high definition, the scanning speed is increased in the optical scanning in which the electrostatic latent image is written on the photosensitive member while scanning with the laser beam, and the resolution of the written image is increased. This is one of the specific solutions.
In terms of speeding up, the laser beam is scanned by rotating the rotating polygonal mirror, so it can be realized by increasing the rotation speed of the rotating polygonal mirror. Vibration due to the dynamic balance of the main body, and rotational vibrations of driving elements such as motors and gears of the main body drive system are also applied, so that the optical element in the optical scanning device vibrates and the light on the surface of the photosensitive member Since the scanning position shifts and the density unevenness of the image is generated, the image quality is deteriorated, resulting in a problem against high definition.
[0003]
In particular, the folding mirror in the optical scanning device is often long because it requires a mirror surface covering the scanning range, and as a result of consideration that the scanning light is not blocked by the support member when supporting it. In many cases, both ends of the mirror are supported. For this reason, vibration with a large amplitude is likely to occur at the center of the mirror.
FIG. 5 shows an example of the configuration of such a conventional optical scanning device. Further, FIG. 6 shows the arrangement of optical elements constituting the optical scanning device.
As shown in FIGS. 5 and 6, the optical scanning device includes a rotary polygon mirror 51, a rotary polygon mirror drive motor 52, a toroidal lens 53, transmission glasses 54 and 57, a first folding mirror 55, a second folding mirror 56, The photosensitive member 58, the fθ mirror 59, the optical box 61, the semiconductor laser unit 62, the folding mirror 63, the cylindrical lens 64, the synchronization detecting plate 65, and the folding mirror 66 are provided as constituent elements.
The optical path of the laser beam in the apparatus will be schematically described with reference to FIG. First, the laser beam emitted from the light source in the semiconductor laser unit 62 is deflected by the rotary polygon mirror 51, passes through the transmission glass 54, travels along the optical axis 60 toward the fθ mirror 59, the first folding mirror 55, and the toroidal. An image is formed on the photoreceptor 58 through the lens 53, the second folding mirror 56, and the transmission glass 57.
[0004]
The folding mirror used as a component of the conventional optical scanning device shown in FIGS. 5 and 6 will be described in detail with reference to FIG. The folding mirror support portion shown in FIG. 7 shows a typical example of the conventional configuration, and the folding mirror 71 is supported by springs 73 near both ends so as not to block the beam in the image writing utilization range 71w of the laser beam. is pressed against the member 72 ₁ and 72 ₂ (not shown spring is present in a position facing the support member 72 _1), thereby are determined inclination of the reflecting surface.
This state is shown in FIG. 8 when FIG. 7 is viewed from the direction of arrow A. Contact surface of the tilt of the reflecting surface of the mirror support member 72 _1, 72 ₂ in order to maintain good accuracy is in the shape close to point contact to reduce. When the mirror in such a support state is viewed from the direction B in FIG. 7, it becomes a shape close to a beam of both-side free end support as shown in FIG. The folding mirror in the optical scanning device is often long, and is very easy to vibrate in such a form of free-end support on both sides, and vibrates in a mode as shown in FIG. Amplitude is represented by S1, and as described above, the problem of deterioration in image quality occurs.
There are examples of countermeasures such as increasing the thickness of the mirror in order to increase the rigidity of the mirror or attaching a plate glass or vibration isolating material to the back of the mirror, but this increases the cost considerably. .
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems that occur in the speeding up of the conventional optical scanning device, and its object is to support both ends of a long mirror surface that covers the scanning range of a laser beam. Provided is an optical scanning device capable of reducing or suppressing a vibration having a large amplitude that is likely to occur at the center of a folding mirror having a structure and capable of high-speed operation.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is an optical scanning device having an optical deflector for deflecting a light beam and a mirror for reflecting a scanning light beam deflected by the optical deflector, on which the scanning light beam carrying an image is projected. that effectively with use with an excess length portion plus main scanning direction in the range, the effective scanning direction sides close to the range of use positions and at least three of the extra length portion of the outer side portions of the two side The support member and the pressing member that presses the mirror against the support member are arranged to face each other via the mirror at the support location .
[0007]
According to a second aspect of the present invention, in the optical scanning device according to the first aspect, the extra length portions are provided on both sides in the scanning direction of the effective use range.
[0008]
According to a third aspect of the present invention, in the optical scanning device according to the first or second aspect, at least one of the other support locations excluding a location that functions to maintain the tilt of the reflecting surface of the mirror in the support location. One is supported through an elastic body in contact with the reflecting surface of the mirror.
[0009]
According to a fourth aspect of the present invention, in the optical scanning device according to any one of the first to third aspects, the other support except for the portion that functions to maintain the inclination of the reflecting surface of the mirror in the support portion. At least one of the locations is supported via a vibration isolator.
[0010]
According to a fifth aspect of the present invention, in the optical scanning device according to any one of the first to fourth aspects, a spring member is provided to press the reflecting surface of the mirror against the support member at each support location in order to support the mirror by the support member. It is characterized by this.
[0011]
According to a sixth aspect of the present invention, in the optical scanning device according to the fifth aspect, the spring member is a single member that works in common at a plurality of support locations.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An optical scanning device according to the present invention will be described with reference to the following embodiments shown in the accompanying drawings. Note that the basic configuration of the entire optical scanning apparatus can be implemented by adopting the same configuration as that shown as the prior art in FIGS. 5 and 6 above, so that the description thereof will be omitted. Examples of the folding mirror portion having the components unique to the present invention will be described below.
[0013]
FIG. 1 shows an embodiment of a folding mirror constituting an optical scanning device according to the present invention.
In the embodiment shown in FIG. 1, the folding mirror 1 is used in an image writing use range 1w (the scanning light beam projected in this range bears an image written on the photosensitive member and is effectively used to form an image after reflection. ) With a predetermined length longer in the main scanning direction of the scanning light, the support members 2 ₂ and 2 ₃ near the image writing use range 1w, and the mirror 1 away from the image writing use range 1w. Support members 2 ₁ and 2 ₄ are provided near the ends. Although not shown, (in FIG. 1, it is shown only the leaf spring 3 ₁₎ These four support each plate spring on the back surface of the opposing mirror member comprises a mirror 1 by these leaf springs are each supported It is pressed against the members 2 _{1 to} 2 ₄ . While here has a shape in which the supporting member 2 ₃ undergo folding mirror 1 at two points of top and bottom, which are intended to keep the inclination of the folding mirror 1 in a predetermined amount, or in other ways. For example, when such shifting the position in the height direction of the mirror receiving plane of the support section analysis 2 ₂ and the support part analysis 2 _1, the support part analysis 2 ₃ need not be divided up and down.
[0014]
When FIG. 1 is viewed from the direction of arrow C, it is simply represented as shown in FIG. (The maximum amplitude of the mirror 1 is represented by S2) As described above, the vibration of the folding mirror can be reduced (S1> S2) by increasing the support points in the main scanning direction as compared with FIG. 9 showing the conventional configuration example. it can. Further, by setting an appropriate distance between the support members 2 _{1 to} 2 ₄ , the natural frequency of the folding mirror 1 can be freely determined to some extent. For example, the drive frequency of the main motor of the laser printer main body and the mirror It is possible to intentionally shift the natural frequency and the like, and it is possible to efficiently reduce the vibration of the mirror rather than simply increasing the rigidity of the mirror.
[0015]
Although FIG. 1 shows an example in which two support points are provided in the main scanning direction of light on both the upstream side and the downstream side in the main scanning direction of the portion outside the image writing use range 1w of the mirror. in the present invention, a support member provided in addition to the image writing utilization range supporting member 2 ₂ provided as close to 1 w, 2 ₃ need not necessarily two, it may be more than four, also any one when in the context of installation space not sufficiently take the length of the mirror may, for example in the Figure 1, eliminates the support member 2 _4, oscillation of the mirror in comparison with the conventional example of FIG. 7 in this case Can be reduced.
[0016]
FIG. 3 shows the configuration of another embodiment according to the present invention.
This embodiment is common in the basic configuration to the embodiment shown in FIG. 1, except that rubber cushions 4 ₁ and 4 ₄ are provided on support members 2 ₁ and 2 ₄ provided at both ends of the mirror. The mirror 1 is pressed against the rubber cushions 4 ₁ and 4 ₄ and the supporting members 2 ₂ and 2 ₃ by a leaf spring (only the leaf spring 3 ₁ is shown in FIG. 1). The inclination of the mirror is determined by three receiving surfaces provided on the support members 2 ₂ and 2 ₃ , and plate springs are provided on the back surfaces of the mirrors facing the rubber cushions 4 ₁ and 4 ₄ , respectively. Supports not to deteriorate the degree.
The rubber cushions 4 ₁ and 4 ₄ are preferably made of rubber having a high vibration proof property.
FIG. 3 is merely an example of the configuration, and in the present invention, the numbers and positions of the support members and the rubber cushions do not have to be as shown in FIG. In other words, at least three support members are provided on both the upstream side and the downstream side in the main scanning direction of the portion outside the image writing utilization range 1w, and rubber cushions are not provided at two of them. As long as this requirement is satisfied, the number of support members and the number of rubber cushions and the conditions of the positions may be changed.
[0017]
FIG. 4 shows the configuration of another embodiment according to the present invention.
Fig In 4, the mirror 1 is visible back side of the reflecting surface, each support member to the mirror surface facing the total of four spring portion of the leaf spring 3 ₁ and 3 ₂ consisting of a pair of springs (Fig. 4 in, shown only the supporting member 2 ₂₎ is provided. By adopting this leaf spring, the number of parts is reduced, the configuration and assembly work are simplified, and workability is also good.
[0018]
【The invention's effect】
According to the invention of claim 1, 2, of the both sides in the scanning direction the scanning light beam used for the image writing is close to the effective utilization range of the mirror to be projected portion and the excess length portion of the outer side portions of the two side The long mirror of this type of optical scanning device has a simple configuration in which the supporting member and the pressing member that presses the mirror against the supporting member are arranged to face each other via the mirror at at least three supporting points. Thus, the amplitude of vibration generated in the image can be reduced, and the performance of image writing can be improved.
[0019]
According to the third aspect of the invention, by supporting the mirror via the elastic body in contact with the reflecting surface, the effects of the first and second aspects can be obtained without deteriorating the flatness of the reflecting surface.
[0020]
According to the invention of claim 4, in addition to the effects of the inventions of claims 1 to 3, the vibration of the mirror can be reduced more efficiently by suppressing the vibration by the vibration isolator.
[0021]
According to the fifth and sixth aspects of the present invention, a means that operates reliably with a simple configuration can be provided as a specific means for supporting the mirror. According to the invention of claim 6, the number of parts is reduced, and the assembly workability is good.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a folding mirror constituting an optical scanning device according to the present invention.
2 is a simplified diagram showing a state of vibration when the folding mirror shown in FIG. 1 is viewed from the direction of arrow C. FIG.
FIG. 3 shows the configuration of another embodiment of the folding mirror constituting the optical scanning device according to the present invention.
FIG. 4 shows a configuration of still another embodiment of a folding mirror constituting the optical scanning device according to the present invention.
FIG. 5 shows an example of the configuration of a conventional optical scanning device.
6 shows an arrangement of optical elements constituting the optical scanning device shown in FIG.
FIG. 7 shows an example of a folding mirror which is a constituent element of a conventional optical scanning device.
8 is a view of the folding mirror shown in FIG. 7 as viewed from the direction of arrow A. FIG.
9 is a simplified diagram showing a state of vibration when the folding mirror shown in FIG. 7 is viewed from the direction of arrow B. FIG.
[Explanation of symbols]
1 ... Folding mirror, 1w ... Image writing usage range,
2 _{1 to} 2 ₄ ... support member, 3 ₁ , 3 ₂ ... leaf spring,
4 ₁ , 4 ₄ ... rubber cushion,
51 ... Rotating polygon mirror, 52 ... Rotating polygon mirror drive motor,
53 ... Toroidal lens, 54 ... Transmission glass,
55 ... 1st folding mirror, 56 ... 2nd folding mirror,
57 ... Transmission glass, 58 ... Photoconductor, 59 ... fθ mirror,
60 ... optical axis, 61 ... optical box,
62 ... Semiconductor laser unit, 63 ... Folding mirror,
64, 66 ... cylindrical lens, 65 ... synchronization detection plate,
71 ... Folding mirror, 71w ... Image writing use range,
72 ₁ , 72 ₂ ... support members,
73 ... leaf spring, 74 ... screw,
75: Incident light, 76: Reflected light.

Claims

In an optical scanning device having an optical deflector for deflecting a light beam and a mirror for reflecting a scanning light beam deflected by the optical deflector,
The mirror, with the scanning light beam played image has an extra length portion in addition the main scan direction enable usage range to be projected, from the effective scanning direction sides close to the range of use positions and the two side portions An optical scanning characterized in that a support member and a pressing member that presses the mirror against the support member are arranged to face each other through the mirror at at least three support points of the extra length portion on the outside. apparatus.

2. The optical scanning device according to claim 1, wherein the extra length portion is provided on both sides of the effective use range in the scanning direction.

3. The optical scanning device according to claim 1, wherein at least one of the other support portions excluding a portion that functions to maintain the inclination of the reflection surface of the mirror in the support portion is a reflection surface of the mirror. An optical scanning device characterized in that the optical scanning device is supported via an elastic body in contact therewith.

4. The optical scanning device according to claim 1, wherein at least one of the other support portions excluding a portion that functions to maintain the inclination of the reflecting surface of the mirror in the support portion is an anti-vibration unit. An optical scanning device characterized by being supported through a material.

5. The optical scanning device according to claim 1, further comprising: a spring member that presses the reflecting surface of the mirror against the support member at each support location in order to support the mirror by the support member. 6. apparatus.

6. The optical scanning device according to claim 5 , wherein the spring member is a single member that works in common for a plurality of support locations.