JPS604936A - Optical scanning exposure device - Google Patents

Abstract

PURPOSE:To correct intensity of illumination irregularity in a scanning direction and uniform intensity of illumination by arranging a light shield member which is parallel to the lengthwise direction of a slit for exposure between a projection lens and a photosensitive body. CONSTITUTION:When pieces of focusing luminous flux (a)-(d) having angles of views from a film 1 to a lens 2 are projected on the photosensitive body 5, the quantities of light are limited by the slit 7 for exposure. The light shield member 6 is arranged fixedly between moving optical systems 3 and 4, and slit 7 for exposure in the lengthwise direction of the slit; and part of the forcussing luminous flux (a) at the center part of the film is cut off so that the amount of light shielding decreases gradually according to the distance from the center part, and neither the pieces (b) nor (c) of focussing luminous flux at a film end part is cut off. The quantity of exposure becomes less and less toward the film center part, so the intensity of illumination irregularity in the scanning direction is corrected.

Description

【発明の詳細な説明】 本発明は、静止したマイクロフィルム等の原稿の像を移
動光学系により投影し、その投影像を移動する感光体へ
スリット露光する光学走査露光装置、特に感光体表面の
照度ムラを補正する上記の装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical scanning exposure device that projects an image of a stationary document such as a microfilm using a moving optical system, and exposes the projected image to a moving photoreceptor using a slit. The present invention relates to the above device for correcting uneven illuminance.

従来、静止した原稿、例えばマイクロフィルムを移動す
る感光体に拡大投影する方法として、フィルム移動方式
、投影レンズ移動方式及び像界走査方式があるが、最初
の２つの方式は変倍時には、それぞれフィルムやレンズ
の移動速度を変える必要があり、構成が複雑になるため
第７図に示すような像界走査方式が提案されている。こ
の方式は第１図にお℃・て、固定したフィルム／の固定
した投影レンズユによる投影像を像界側で同期して移動
する光学系（ミラー）３及びケを介して移動感光体３に
スリット露光する方式であるが、変倍時でも移動光学系
３及びグの走査速度が一定であるため、構成も比較的簡
単となる。Conventionally, methods for enlarging and projecting a stationary document, such as microfilm, onto a moving photoreceptor include a film movement method, a projection lens movement method, and an image field scanning method. Since it is necessary to change the speed of movement of the lens and the moving speed of the lens, and the configuration becomes complicated, an image field scanning method as shown in FIG. 7 has been proposed. In this method, as shown in Fig. 1, the projected image of a fixed film by a fixed projection lens unit is transferred to a movable photoreceptor 3 via an optical system (mirror) 3 that moves synchronously on the image field side. Although this is a slit exposure method, the scanning speed of the moving optical system 3 and the moving optical system 3 is constant even when changing the magnification, so the configuration is relatively simple.

しかしながら、本方式では第１図に示すようにフィルム
／の画像Ａの結像光束ａ及び画像Ｂの結像光束すは、そ
れぞれ移動光学系３．７及び移動した移動光学系３／　
、　ｌｌ／により、感光体夕のＥに異なった角度でスリ
ット投影され（つまりレンズに対する光束入射角が原稿
走査にともなって変化する）その結果、感光体上にはレ
ンズの６０８９乗則による照度ムラが生じる。更にマイ
クロフィルムの照明系によるムラが加わる。このような
照度ムラを補正する為に、従来は透過光量を不均一にし
た光学フィルターを用処・たり、露光スリット全体を一
体的１（回転させたりしているが、前音は製作に難点が
あり、後者は構成が複雑になるという欠点がある。However, in this method, as shown in FIG.
, ll/, the slit is projected at different angles onto E of the photoconductor (that is, the angle of incidence of the light beam on the lens changes as the original is scanned).As a result, there is illuminance unevenness on the photoconductor due to the 6089th power law of the lens. occurs. Furthermore, unevenness due to the microfilm lighting system is added. In order to correct such uneven illuminance, conventional methods have used optical filters that make the amount of transmitted light uneven, or rotated the entire exposure slit in one piece, but the foreground is difficult to manufacture. However, the latter has the disadvantage that the configuration is complicated.

本発明は、上記の欠点を解消するために為されたもので
、投影レンズと感光体の間の光路中の感光体近傍位置に
露光用スリットを配置し、更にスリット長手方向に平行
な固定の遮光部材を配置することにより、特に走査方向
の照度ムラを補正して露光領域全体に亘り感光体面上で
のその移動方向についての照度の均一化が可能な光学走
査露光装置を提供することを目的とする。The present invention has been made to eliminate the above-mentioned drawbacks, and includes an exposure slit arranged near the photoconductor in the optical path between the projection lens and the photoconductor, and a fixed slit parallel to the longitudinal direction of the slit. An object of the present invention is to provide an optical scanning exposure device that can correct illuminance unevenness in the scanning direction and make the illuminance uniform in the moving direction on the surface of a photoreceptor over the entire exposure area by arranging a light shielding member. shall be.

以下、本発明の詳細な説明の一実施例を示す第２図に従
って説明する。ａ、ｂ、ｃ、ｄは、それぞれレンズコに
対するフィルム／の各画角の結像光束で、感光体Ｓに投
影される際、露光用スリット７によって、光量が制限さ
れる。該露光用スリットは、その長手方向で開口が変え
てあり、長手方向の照度ムラを補正する働きを有する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to FIG. 2, which shows an embodiment of the present invention. A, b, c, and d are imaging light fluxes at respective angles of view of the film and the lens, respectively, and when projected onto the photoreceptor S, the amount of light is limited by the exposure slit 7. The exposure slit has an opening that varies in its longitudinal direction, and has the function of correcting uneven illuminance in the longitudinal direction.

乙は遮光部材で、移動光学系と露光用スリット７の間に
、該露光用スリットの長手方向に平行に、固定して配置
される。遮光部材乙は、フィルム中心部分の結像光束ａ
の一部を遮光し、フィルム中心部分から遠ざかるに従っ
て、初めのうちは、はとんど同じだけ遮光するが、その
後の結像光束ｄから遮光量が漸減し、フィルム端部分の
結像光束す。Reference numeral B denotes a light shielding member, which is fixedly arranged between the moving optical system and the exposure slit 7 in parallel to the longitudinal direction of the exposure slit. The light shielding member B is the imaging light beam a at the center of the film.
As you move away from the center of the film, at first the light is blocked by almost the same amount, but then the amount of light blocked from the imaging light flux d gradually decreases, and the imaging light flux at the edge of the film is completely blocked. .

Ｃでは遮光しないようにする。In C, do not block light.

この様な遮光部材を設ければ、フィルム中心部分に近づ
くほど露光量が少なくなるために、走査方向の照度ムラ
を補正することが可能となる。If such a light shielding member is provided, the amount of exposure decreases as the film gets closer to the center, so it becomes possible to correct uneven illuminance in the scanning direction.

なお更に、他の一実施例として第３図に示すように、遮
光部材ろをコ枚用いてそれぞれ結像光束す及びＣにほぼ
平行に配置することにより、同様に走査方向の照度ムラ
を補正することができる。Furthermore, as another example, as shown in FIG. 3, unevenness in illuminance in the scanning direction can be similarly corrected by using several light shielding members and arranging them approximately parallel to the imaging light beams C and C. can do.

この場合、遮光量はフィルム中心部分より遠ざかるに従
い徐々に減少する。In this case, the amount of light shielding gradually decreases as the distance from the center of the film increases.

また、遮光部材乙の形状としては、本実施例で用いた板
状の他に断面が円形のワイヤー状のものでも効果は得ら
れる。Further, as for the shape of the light shielding member B, in addition to the plate shape used in this embodiment, the effect can also be obtained by using a wire shape with a circular cross section.

以上、説明したように本発明は、露光用スリットを有し
、原稿を走査するにつれて感光体への光束入射角が変化
して行く光学走査露光装置において、該スリットの長手
方向に平行な固定の遮光部材を設けることにより、特に
走査方向の照度ムラ補正を可能にする効果がある。As described above, the present invention provides an optical scanning exposure device that has an exposure slit and changes the angle of incidence of a light beam onto a photoreceptor as a document is scanned. Providing the light shielding member has the effect of making it possible to correct illuminance unevenness, especially in the scanning direction.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は、本発明を適用した像界走査方式の光学走査露
光装置を示す模式図、第２図及び第３図は、それぞれ照
度ムラ補正部材（遮光部材）の一実施例、及び他の実施
例である。 ／・・・・・・フィルム、ｅ２．・・・・・・投影レン
ズ。 ３、　’ｌ・・・移動光学系、　５・・・・・・感光体
。 乙・・・・・・遮光部材、７・・・・・・露光用スリッ
ト。 特許出願人　キャノン株式会社 ヒ 第３図FIG. 1 is a schematic diagram showing an image field scanning type optical scanning exposure apparatus to which the present invention is applied, and FIGS. 2 and 3 show one embodiment of an illuminance unevenness correction member (light shielding member) and another embodiment, respectively. This is an example. /...Film, e2. ...projection lens. 3.'l...Moving optical system, 5...Photoreceptor. B: Light shielding member, 7: Exposure slit. Patent applicant: Canon Co., Ltd. Figure 3

Claims (1)

【特許請求の範囲】[Claims] 露光用スリットを有し、原稿を走査するにつれて感光体
への光束入射角が変化して行く光学走査露光装置におい
て、上記スリットの長手方向に平行な固定の遮光部材を
配置することを特徴とする光学走査露光装置。An optical scanning exposure device having an exposure slit and in which the angle of incidence of a light beam on a photoreceptor changes as a document is scanned, characterized in that a fixed light shielding member is disposed parallel to the longitudinal direction of the slit. Optical scanning exposure device.