JP3559402B2 - Optical printer head - Google Patents

Optical printer head Download PDF

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Publication number
JP3559402B2
JP3559402B2 JP28874896A JP28874896A JP3559402B2 JP 3559402 B2 JP3559402 B2 JP 3559402B2 JP 28874896 A JP28874896 A JP 28874896A JP 28874896 A JP28874896 A JP 28874896A JP 3559402 B2 JP3559402 B2 JP 3559402B2
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Prior art keywords
light emitting
emitting element
light
lens
printer head
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JPH10129035A (en
Inventor
俊次 村野
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Kyocera Corp
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Kyocera Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/435—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material
    • B41J2/447—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources
    • B41J2/45—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of radiation to a printing material or impression-transfer material using arrays of radiation sources using light-emitting diode [LED] or laser arrays
    • B41J2/451—Special optical means therefor, e.g. lenses, mirrors, focusing means

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Mounting And Adjusting Of Optical Elements (AREA)
  • Facsimile Heads (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は電子写真プリンタ等の露光装置として組み込まれる光プリンタヘッドの改良に関する。
【０００２】
【従来の技術】
近年、光プリンタヘッドの光学系として非球面レンズを用いることが提案されており、かかる非球面レンズはビームのすそ引きが少なく、隣接する発光素子からの光の干渉による影響を受けにくい特性を有していることから、解像度が高く、高精度の重ね合わせが必要なカラーグラフィック等の用途に適したものとして注目されている。
【０００３】
このような従来の光プリンタヘッドは、例えば、ガラスやセラミック等から成るベースプレート上に、複数個の発光素子が一定のピッチで配列された発光素子アレイを複数個、直線状に配列実装させるとともに、前記発光素子アレイ上に複数個の非球面レンズを配設した構造を有しており、前記各発光素子アレイの各発光素子を外部からの印画信号に対応させて個々に選択的に発光させるとともに、該発光素子の発した光（ビーム）を非球面レンズを介して外部の感光体に結像させ、感光体面に所定の潜像を形成することによって光プリンタヘッドとして機能する。
【０００４】
尚、前記発光素子アレイとしては、例えば、同一サイズの発光ダイオード素子（以下、ＬＥＤと略記する）を６４個、直線状に配列させて成るＬＥＤアレイ等が用いられ、かかるＬＥＤアレイを用いてＡ４サイズ、３００ｄｐｉの光プリンタヘッドを形成する場合には、４０個のＬＥＤアレイをその各々が前述した非球面レンズと１対１に対応するようにしてベースプレート上に載置させることにより光プリンタヘッドが構成される。
【０００５】
【発明が解決しようとする課題】
しかしながら、この従来の光プリンタヘッドにおいては、光学系として用いられる非球面レンズが所定の収差を有しており、該レンズの周辺域を透過するビームの輪郭が前記収差によって若干、ぼやける傾向がある。このため、各発光素子アレイの両端域に位置する発光素子からのビームの強度が中央域に位置する発光素子からのものよりも弱くなってしまい、その結果、感光体上に照射されるビームの強度、大きさにバラツキを生じて印画の濃度むらが形成される欠点を有している。
【０００６】
【課題を解決するための手段】
本発明は上記欠点に鑑み案出されたもので、ベースプレート上に、多数の発光素子が直線状に配列された発光素子アレイを複数個、列状に配置させるとともに、これら発光素子アレイ上に該アレイと１対１に対応する複数個の非球面レンズを配設させて成る光プリンタヘッドであって、前記各発光素子アレイの両端域に位置する発光素子の長さを中央域に位置する発光素子よりも長くなし、且つ該発光素子アレイと前記非球面レンズとの間に前記発光素子の長さに対応させて曲率を両端部で大きく、中央部で小さくなるように変化させたシリンドリカルレンズを配置したことを特徴とする。
【０００７】
【発明の実施の形態】
以下、本発明を添付図面に基づいて詳細に説明する。
【０００８】
図１は本発明の光プリンタヘッドの一形態を示す縦断面図、図２は図１の光プリンタヘッドの横断面図であり、１はベースプレート、２は発光素子アレイ、２ａは発光素子、３は非球面レンズ、４はシリンドリカルレンズである。
【０００９】
前記ベースプレート１は透光性を有する絶縁材料、例えば石英やサファイア、結晶化ガラス、ホウケイ酸ガラス等から成り、その下面には複数個の発光素子アレイ２やこれら発光素子アレイ２に外部電源からの電力を供給するための配線導体（図示せず）等が取着されている。
【００１０】
前記複数個の発光素子アレイ２はその各々が、四角形状を成す多数の発光素子２ａを一定のピッチで直線状に配列させて成り、該各発光素子２ａを印画信号に対応させて個々に選択的に発光させ、該発光した光（ビーム）を後述するシリンドリカルレンズ４及び非球面レンズ３を介して外部の感光体Ｐに照射させることによって感光体Ｐに所定の潜像を形成する。
【００１１】
このような発光素子アレイ２は、発光素子２ａとしてＧａＡｓＰ系、ＧａＡｌＡｓ系のＬＥＤ等を用い、例えばＧａＡｓＰ系ＬＥＤの場合は、まずＧａＡｓの基板を炉中にて高温に加熱するとともにＡｓＨ３ （アルシン）とＰＨ３ （ホスヒン）とＧａ（ガリウム）を適量に含むガスを接触させて基板表面にｎ型半導体のＧａＡｓＰ（ガリウム−砒素−リン）の単結晶を成長させ、次にＧａＡｓＰ単結晶表面にＳｉ３ Ｈ４ （窒化珪素）の窓付膜を被着させるとともに該窓部にＺｎ（亜鉛）のガスをさらし、ｎ型半導体のＧａＡｓＰ単結晶の一部にＺｎを拡散させてｐ型半導体を形成し、ｐｎ接合をもたすことによって形成される。
【００１２】
尚、前記発光素子アレイ２はＡ４サイズ、３００ｄｐｉの光プリンタヘッドを形成する場合、６４個の発光素子２ａを一単位とした発光素子アレイ２を４０個、その発光面がベースプレート１の下面と対向するようにしてベースプレート１上に配列させ、これらをフリップチップ実装すること、具体的には、発光素子アレイ２の発光面と同一面に形成される多数の端子電極をベースプレート１上の配線導体に対し半田等のロウ材を介して電気的・機械的に接続させることによってベースプレート１の下面に取着される。
【００１３】
一方、前記発光素子アレイ２が配列実装されるベースプレート１の上面側には複数個の非球面レンズ３が、該非球面レンズ３と発光素子アレイ２とが１対１に対応するようにして併設固定されている。
【００１４】
前記複数個の非球面レンズ３は各発光素子２ａの発する光を所定の倍率で拡大し、これを感光体面Ｐに照射・結像させるためのものであり、液晶ポリマー等から成るレンズプレート５等によって支持され、該レンズプレート５の厚み方向に設けられた光透過用の穴５ａを塞ぐようにしてレンズプレート５上に接着固定される。
【００１５】
尚、前記非球面レンズ３は、アクリル樹脂やポリカーボネイト樹脂等の透明樹脂を射出成形したり、或いはガラス等の透光性無機物を加熱プレス成形することによって所定形状に加工される。
【００１６】
また前記ベースプレート１及び複数個の非球面レンズ３を有するレンズプレート５はハウジング部材６に固定させることによって各発光素子アレイ２と各非球面レンズ３とが所定の間隔を隔てて１対１に対応するように併設されている。
【００１７】
前記ハウジング部材６はその上部に第１の基準面６ａを、下部に第２の基準面６ｂを有しており、ハウジング部材６の第１基準面６ａにレンズプレート５の下面外周部を、ハウジング部材６の第２基準面６ｂにベースプレート１の上面外周部を各々、当接固定させることによって各発光素子アレイ２と各非球面レンズ３とは間に所定の距離を隔てて１対１に対応するようになっている。
【００１８】
そして前述した各発光素子アレイ２は、図３に示すように、各発光素子アレイ２の両端域に位置する発光素子２ａの長さＬ１（発光素子２ａの配列方向と直交する方向にかかる寸法）が中央域に位置する発光素子２ａの長さＬ２よりも長くなるように設定されており、更に、このような発光素子アレイ２と非球面レンズ３との間には、発光素子２ａの長さに対応させて曲率（曲率半径の逆数）を変化させた平凸型のシリンドリカルレンズ４が配置されている。
【００１９】
前記発光素子アレイ２は、例えば、６４個の発光素子２ａを用いて３００ｄｐｉの線密度で発光素子アレイ２を形成する場合、中央域に位置する発光素子２ａの長さＬ２を５０μｍに、また両端域に位置する発光素子２ａの長さＬ１を５５〜６０μｍの範囲内にそれぞれ設定する。このような発光素子アレイ２の各発光素子２ａに電流密度を等しくなすようにして電力を印加すると、ベースプレート１を介してシリンドリカルレンズ４に入射する発光素子アレイ２からのビームの長さは各発光素子２ａの長さに応じてそれぞれ異なる。
【００２０】
また一方、このようなビームが透過するシリンドリカルレンズ４は、発光素子２ａからのビームをシリンドリカルレンズ４の曲率に応じて発光素子２ａの長さ方向（副走査方向）にのみ集光・縮小させるためのもので、図４に示すように、シリンドリカルレンズ４の曲率は、発光素子２ａの長さと同様に、その両端部で大きく、また中央部で小さくなるように変化しているため、シリンドリカルレンズ４を透過して非球面レンズ３に入射する発光素子アレイ２からのビームはその大きさを全て等しくなすことができる。しかも、発光素子アレイ２からのビームの集光率はその両端域で高くなっていることから、該集光したビームの強度も発光素子アレイ２の両端域で高い。このため、非球面レンズ３の周辺域を透過するビームの輪郭がレンズ３の収差によって若干ぼやけたとしても、各発光素子２ａの長さ及びシリンドリカルレンズ４の曲率を適宜設定しておくことにより、非球面レンズ３を介して感光体Ｐ上に照射される全てのビームの強度、大きさをほぼ等しく揃えることができ、これによってビームぼけの発生を有効に防止するとともに、濃度むらの無い良好な印画を形成することが可能となる。
【００２１】
尚、このような発光素子２ａの長さは、非球面レンズ３のレンズ特性によって適宜、設定されるものであり、例えば、収差による影響が両端に向かって次第に強く表れる非球面レンズ３の場合には、両端域に位置する発光素子２ａの長さを両端に向かって２〜５μｍずつ長くなるように設定し、シリンドリカルレンズ４の曲率もこれに応じて変化させるようにすれば良い。
【００２２】
また、このようなシリンドリカルレンズ４は、アクリル樹脂やポリカーボネイト樹脂等の透明樹脂を射出成形したり、或いはガラス等の透光性無機物を加熱プレス成形することによって所定形状に加工され、更にこれらを発光素子アレイ２の真上に位置するベースプレート１の上面にエポキシ系接着剤，アクリル系接着剤等を用いて接着固定することによりベースプレート１上に実装される。このとき、シリンドリカルレンズ４はベースプレート１によって支持されるため、別途レンズプレート等を用いる必要はなく、シリンドリカルレンズ４の位置合わせや光プリンタヘッドの構成が比較的簡単である。
【００２３】
かくして上述した光プリンタヘッドは、各発光素子アレイ２の各発光素子２ａを印画信号に対応させて個々に選択的に発光させるとともに、該発光素子２ａの発する光（ビーム）をシリンドリカルレンズ４及び非球面レンズ３を介して外部の感光体Ｐに結像させ、感光体Ｐに所定の潜像を形成することによって光プリンタヘッドとして機能する。
【００２４】
尚、本発明は上述の実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲において種々の変更、改良等が可能であり、例えば、上述した形態において隣接する非球面レンズ３間に遮蔽部材７を配置させても良く、このような遮蔽部材７を用いることによって隣接する発光素子アレイ２からのビームによりゴースト像が形成されるのを有効に防止することができる。
【００２５】
また上述した形態においては発光素子アレイとしてＬＥＤアレイを用いたＬＥＤプリンタヘッドを例に説明したが、ＥＬヘッド、プラズマドットヘッド、液晶シャッタヘッド、蛍光ヘッド、ＰＬＺＴ等の光プリンタヘッドにも適用可能である。
【００２６】
【発明の効果】
本発明の光プリンタヘッドによれば、各発光素子アレイの両端域に位置する発光素子の長さを中央域に位置する発光素子よりも長くなし、発光素子アレイと非球面レンズとの間に発光素子の長さに対応させて曲率を両端部で大きく、中央部で小さくなるように変化させたシリンドリカルレンズを配置したことから、非球面レンズを介して感光体上に照射される全てのビームの強度、大きさをほぼ等しく揃えることができ、これによってビームぼけの発生を有効に防止して濃度むらの無い良好な印画を形成することが可能となる。
【図面の簡単な説明】
【図１】本発明の光プリンタヘッドの一形態を示す縦断面図である。
【図２】図１の光プリンタヘッドの横断面図である。
【図３】発光素子アレイ２を構成する各発光素子２ａの長さを示した模式図である。
【図４】発光素子アレイ２からのビームがシリンドリカルレンズ４を透過する様子を模式的に示す斜視図である。
【符号の説明】
１・・・ベースプレート
２・・・発光素子アレイ
２ａ・・発光素子
３・・・非球面レンズ
４・・・シリンドリカルレンズ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in an optical printer head incorporated as an exposure device such as an electrophotographic printer.
[0002]
[Prior art]
In recent years, it has been proposed to use an aspherical lens as an optical system of an optical printer head. Such an aspherical lens has a characteristic that it has a small beam tail and is hardly affected by light interference from an adjacent light emitting element. Therefore, it has been drawing attention as being suitable for applications such as color graphics that require high resolution and high-precision superposition.
[0003]
Such a conventional optical printer head, for example, on a base plate made of glass, ceramics and the like, a plurality of light emitting element arrays in which a plurality of light emitting elements are arranged at a fixed pitch, while linearly arranged and mounted, It has a structure in which a plurality of aspherical lenses are arranged on the light emitting element array, and each light emitting element of each light emitting element array selectively emits light corresponding to an external printing signal. The light (beam) emitted from the light emitting element is imaged on an external photoconductor via an aspherical lens, and a predetermined latent image is formed on the photoconductor surface to function as an optical printer head.
[0004]
As the light emitting element array, for example, an LED array in which 64 light emitting diode elements (hereinafter abbreviated as LEDs) of the same size are linearly arranged is used. When an optical printer head having a size of 300 dpi is formed, an optical printer head is formed by mounting 40 LED arrays on a base plate such that each of the LED arrays corresponds to the aspherical lens described above on a one-to-one basis. Be composed.
[0005]
[Problems to be solved by the invention]
However, in this conventional optical printer head, the aspheric lens used as the optical system has a predetermined aberration, and the contour of the beam transmitted through the peripheral area of the lens tends to be slightly blurred due to the aberration. . For this reason, the intensity of the beam from the light emitting elements located at both end areas of each light emitting element array becomes weaker than that from the light emitting element located at the central area, and as a result, the intensity of the beam irradiated on the photoconductor is reduced. There is a disadvantage that unevenness in strength and size is caused to cause unevenness in the density of a print.
[0006]
[Means for Solving the Problems]
The present invention has been devised in view of the above-described drawbacks.A plurality of light-emitting element arrays in which a large number of light-emitting elements are linearly arranged are arranged in a row on a base plate. What is claimed is: 1. An optical printer head comprising a plurality of aspherical lenses arranged one-to-one with an array, wherein light-emitting elements located at both end areas of each of the light-emitting element arrays are positioned at a central area. A cylindrical lens which is not longer than the element, and whose curvature is changed between the light emitting element array and the aspherical lens so as to be larger at both ends and smaller at the center corresponding to the length of the light emitting element. It is characterized by being arranged.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0008]
FIG. 1 is a longitudinal sectional view showing one embodiment of the optical printer head of the present invention, FIG. 2 is a transverse sectional view of the optical printer head of FIG. 1, 1 is a base plate, 2 is a light emitting element array, 2a is a light emitting element, 3 Denotes an aspherical lens, and 4 denotes a cylindrical lens.
[0009]
The base plate 1 is made of an insulating material having a light-transmitting property, for example, quartz, sapphire, crystallized glass, borosilicate glass, etc. On its lower surface, a plurality of light emitting element arrays 2 and these light emitting element arrays 2 are supplied from an external power supply. Wiring conductors (not shown) for supplying power are attached.
[0010]
Each of the plurality of light emitting element arrays 2 is formed by linearly arranging a large number of light emitting elements 2a each having a square shape at a constant pitch, and individually selecting each of the light emitting elements 2a in accordance with a print signal. A predetermined latent image is formed on the photoconductor P by irradiating the external photoconductor P with the emitted light (beam) via a cylindrical lens 4 and an aspheric lens 3 described later.
[0011]
Such a light emitting element array 2 uses a GaAsP-based or GaAlAs-based LED as the light-emitting element 2a. For example, in the case of a GaAsP-based LED, first, a GaAs substrate is heated to a high temperature in a furnace, and AsH 3 (arsine) is used. ), PH 3 (phosphine), and a gas containing an appropriate amount of Ga (gallium) are brought into contact with each other to grow an n-type semiconductor GaAsP (gallium-arsenic-phosphorus) single crystal on the substrate surface, and then on the GaAsP single crystal surface. A window film of Si 3 H 4 (silicon nitride) is deposited, and a window of Zn (zinc) is exposed to the window to diffuse Zn into a part of the n-type semiconductor GaAsP single crystal to convert the p-type semiconductor. And a pn junction.
[0012]
When forming an A4 size, 300 dpi optical printer head, the light emitting element array 2 has 40 light emitting element arrays 2 each having 64 light emitting elements 2a as one unit, and the light emitting surface thereof faces the lower surface of the base plate 1. In this manner, these are arrayed on the base plate 1 and flip-chip mounted. Specifically, many terminal electrodes formed on the same surface as the light emitting surface of the light emitting element array 2 are connected to the wiring conductors on the base plate 1. On the other hand, it is attached to the lower surface of the base plate 1 by being electrically and mechanically connected via a brazing material such as solder.
[0013]
On the other hand, on the upper surface side of the base plate 1 on which the light emitting element array 2 is arranged and mounted, a plurality of aspheric lenses 3 are provided and fixed in such a manner that the aspheric lens 3 and the light emitting element array 2 correspond one to one. Have been.
[0014]
The plurality of aspherical lenses 3 are used to magnify the light emitted from each light emitting element 2a at a predetermined magnification, and irradiate and form an image on the photoconductor surface P, such as a lens plate 5 made of a liquid crystal polymer or the like. And is adhesively fixed on the lens plate 5 so as to close the light transmission hole 5a provided in the thickness direction of the lens plate 5.
[0015]
The aspheric lens 3 is formed into a predetermined shape by injection molding a transparent resin such as an acrylic resin or a polycarbonate resin, or by press-molding a transparent inorganic material such as a glass.
[0016]
The base plate 1 and a lens plate 5 having a plurality of aspheric lenses 3 are fixed to a housing member 6 so that each light emitting element array 2 and each aspheric lens 3 correspond one-to-one with a predetermined interval. It is attached to it.
[0017]
The housing member 6 has a first reference surface 6a on an upper portion thereof and a second reference surface 6b on a lower portion thereof. The outer peripheral portion of the lower surface of the lens plate 5 is provided on the first reference surface 6a of the housing member 6, and By fixing the outer peripheral portion of the upper surface of the base plate 1 to the second reference surface 6 b of the member 6, each light emitting element array 2 and each aspheric lens 3 correspond one-to-one with a predetermined distance therebetween. It is supposed to.
[0018]
As shown in FIG. 3, each of the light emitting element arrays 2 described above has a length L1 (dimension in a direction orthogonal to the arrangement direction of the light emitting elements 2a) located at both end regions of each light emitting element array 2. Is set to be longer than the length L2 of the light emitting element 2a located in the central area, and further, the length of the light emitting element 2a is provided between the light emitting element array 2 and the aspherical lens 3. A plano-convex cylindrical lens 4 whose curvature (the reciprocal of the radius of curvature) is changed corresponding to.
[0019]
When forming the light emitting element array 2 with a linear density of 300 dpi using 64 light emitting elements 2a, for example, the length L2 of the light emitting element 2a located in the central region is set to 50 μm, and both ends are set to 50 μm. The length L1 of the light emitting element 2a located in the region is set within the range of 55 to 60 μm. When power is applied to each light emitting element 2a of such a light emitting element array 2 so as to make the current density equal, the length of the beam from the light emitting element array 2 incident on the cylindrical lens 4 via the base plate 1 becomes equal to each light emission. Each differs depending on the length of the element 2a.
[0020]
On the other hand, the cylindrical lens 4 through which such a beam passes condenses and reduces the beam from the light emitting element 2a only in the length direction (sub-scanning direction) of the light emitting element 2a according to the curvature of the cylindrical lens 4. As shown in FIG. 4, the curvature of the cylindrical lens 4 changes so as to be large at both ends and small at the center similarly to the length of the light emitting element 2a. The beams from the light-emitting element array 2 that pass through and enter the aspherical lens 3 can all have the same magnitude. Moreover, since the light collection rate of the beam from the light emitting element array 2 is high at both end areas, the intensity of the condensed beam is also high at both end areas of the light emitting element array 2. For this reason, even if the contour of the beam transmitted through the peripheral area of the aspherical lens 3 is slightly blurred due to the aberration of the lens 3, by appropriately setting the length of each light emitting element 2 a and the curvature of the cylindrical lens 4, The intensity and magnitude of all the beams irradiated onto the photoconductor P via the aspherical lens 3 can be made substantially equal in intensity, thereby effectively preventing the occurrence of beam blur and providing a good density-free image. A print can be formed.
[0021]
The length of the light emitting element 2a is appropriately set according to the lens characteristics of the aspherical lens 3. For example, in the case of the aspherical lens 3 in which the influence of aberration gradually appears toward both ends. May be set so that the length of the light emitting elements 2a located at both end regions increases by 2 to 5 μm toward both ends, and the curvature of the cylindrical lens 4 may be changed accordingly.
[0022]
Further, such a cylindrical lens 4 is processed into a predetermined shape by injection molding a transparent resin such as an acrylic resin or a polycarbonate resin, or by press-molding a transparent inorganic substance such as a glass, and furthermore, these are made to emit light. It is mounted on the base plate 1 by being adhered and fixed to the upper surface of the base plate 1 located directly above the element array 2 using an epoxy adhesive, an acrylic adhesive or the like. At this time, since the cylindrical lens 4 is supported by the base plate 1, there is no need to use a separate lens plate or the like, and the alignment of the cylindrical lens 4 and the configuration of the optical printer head are relatively simple.
[0023]
Thus, the above-described optical printer head selectively emits each of the light emitting elements 2a of each of the light emitting element arrays 2 in accordance with the printing signal, and emits the light (beam) emitted from the light emitting elements 2a to the cylindrical lens 4 and the non-light emitting element. An image is formed on an external photoconductor P via the spherical lens 3 to form a predetermined latent image on the photoconductor P, thereby functioning as an optical printer head.
[0024]
It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention. The shielding member 7 may be disposed on the light emitting element. By using such a shielding member 7, it is possible to effectively prevent a ghost image from being formed by a beam from the adjacent light emitting element array 2.
[0025]
In the above embodiment, an LED printer head using an LED array as the light emitting element array has been described as an example. However, the present invention can be applied to optical printer heads such as an EL head, a plasma dot head, a liquid crystal shutter head, a fluorescent head, and a PLZT. is there.
[0026]
【The invention's effect】
According to the optical printer head of the present invention, the length of the light emitting elements located at both end areas of each light emitting element array is not longer than that of the light emitting element located at the center area, and light is emitted between the light emitting element array and the aspherical lens. Since a cylindrical lens whose curvature was changed to be large at both ends and small at the center corresponding to the length of the element was arranged, all beams irradiated on the photoreceptor via the aspherical lens were The intensity and the size can be made substantially equal, thereby effectively preventing the occurrence of beam blur and forming a good print without density unevenness.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing one embodiment of an optical printer head of the present invention.
FIG. 2 is a cross-sectional view of the optical printer head of FIG.
FIG. 3 is a schematic diagram showing the length of each light emitting element 2a constituting the light emitting element array 2.
FIG. 4 is a perspective view schematically showing a state in which a beam from a light emitting element array 2 passes through a cylindrical lens 4.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base plate 2 ... Light emitting element array 2a ... Light emitting element 3 ... Aspherical lens 4 ... Cylindrical lens

Claims (1)

ベースプレート上に、多数の発光素子が直線状に配列された発光素子アレイを複数個、列状に配置させるとともに、これら発光素子アレイ上に該アレイと１対１に対応する複数個の非球面レンズを配設して成る光プリンタヘッドであって、
前記各発光素子アレイの両端域に位置する発光素子の長さを中央域に位置する発光素子よりも長くなし、且つ該発光素子アレイと前記非球面レンズとの間に前記発光素子の長さに対応させて曲率を両端部で大きく、中央部で小さくなるように変化させたシリンドリカルレンズを配置したことを特徴とする光プリンタヘッド。A plurality of light-emitting element arrays in which a large number of light-emitting elements are linearly arranged on a base plate, and a plurality of aspherical lenses corresponding to the arrays one-to-one on these light-emitting element arrays. An optical printer head comprising:
The length of the light emitting elements located at both end areas of each of the light emitting element arrays is not longer than that of the light emitting elements located at the central area, and the length of the light emitting elements is between the light emitting element array and the aspherical lens. An optical printer head comprising a cylindrical lens in which the curvature is changed so as to be larger at both ends and smaller at the center .
JP28874896A 1996-10-30 1996-10-30 Optical printer head Expired - Fee Related JP3559402B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP28874896A JP3559402B2 (en) 1996-10-30 1996-10-30 Optical printer head

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Application Number Priority Date Filing Date Title
JP28874896A JP3559402B2 (en) 1996-10-30 1996-10-30 Optical printer head

Publications (2)

Publication Number Publication Date
JPH10129035A JPH10129035A (en) 1998-05-19
JP3559402B2 true JP3559402B2 (en) 2004-09-02

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JP28874896A Expired - Fee Related JP3559402B2 (en) 1996-10-30 1996-10-30 Optical printer head

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Publication number Priority date Publication date Assignee Title
JP2008132760A (en) * 2006-10-26 2008-06-12 Seiko Epson Corp Line head and image formation device using it
JP4930697B2 (en) * 2006-10-26 2012-05-16 セイコーエプソン株式会社 Line head and image forming apparatus using the same

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