JP2004268413A - Beam adjusting device for image formation apparatus, and its adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam adjusting device for an image formation apparatus which enables beam adjustment at the image formation apparatus of a finished product, is easy to separate from the image formation apparatus, and can measure by a measurement precision of the same level as that in the case of a measurement by a scanning optical unit single body. <P>SOLUTION: An attachment means 31a which can be engaged with an attachment means 31b of the image formation apparatus 60 is set integrally with the beam adjusting device 10. The beam adjusting device 10 is set detachably to the attachment means 31b via the attachment means 31a within a space occupied by a photoreceptor unit separated from the image formation apparatus 60. Moreover, when the beam adjusting device 10 is fitted in the space via the attachment means 31a and 31b, a measurement position is disposed at a position corresponding to a photoreceptor surface of the photoreceptor unit. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００７８】
以上のような方法により、各色Ｍ，Ｃ，Ｙ，Ｋそれぞれのドットの位置補正量（ΔＸＭｉ，ΔＹＭｉ），（ΔＸＣｉ，ΔＹＣｉ），（ΔＸＹｉ，ΔＹＹｉ），（ΔＸＫｉ，ΔＹＫｉ）が求まる。
【００７９】
走査ビームの光量に誤差があるときは、その誤差を補正する補正データを光量補正データ演算部４９により画素単位に生成する。すなわち、走査ビームの光量分布を、設計値から求まるピーク光量値とドットサイズと比較することで、発光強度又は点灯時間幅を補正する光量補正データを作成する。
【００８０】
以上のようにして位置補正データと光量補正データとを求めると、ＬＤ発光パターン生成部１７によって、最初に用いた試験用の書込みパターンを位置補正データと光量補正データとで修正した変調信号を設定し、これにより走査ビームを出力して、再度感光体位置に走査させて、測定ヘッド２０で測定することにより、効果確認の試験を行う。この効果確認を経て、最終的に位置補正データと光量補正データとからなる補正データが求まる。
【００８１】
このようにして、画像形成装置６０の各走査光学ユニット１１Ｍ，１１Ｃ，１１Ｙ，１１Ｋごとに補正データを求め、求めた補正データは、該当する画像形成装置６０の記憶装置にテーブルデータとして予め登録しておく。そして、画像形成装置６０は、この補正データを用いて走査ビームの出力の補正を行いながら画像の形成をする。以下では、補正データを用いて画像形成装置６０においてどのような制御を行うかについて説明する。
【００８２】
図１６は、本発明に係る一実施例としての第１実施例のビーム調整装置を適用する、画像形成装置の各走査光学ユニットが備えているパルス幅変調装置等の回路構成例を示すブロック図である。
【００８３】
図１６では、画像形成装置６０の各走査光学ユニット１１Ｍ〜１１Ｋがそれぞれ備えているパルス幅変調部７１等の回路構成例を示す。図１６のパルス幅変調部７１は、ＶＣＯ（電圧制御発振器）８１、分周回路８２、位相比較器または位相周波数比較器８３を有し、位相の異なる複数のパルス、例えばＸ０，Ｘ１，Ｘ２，Ｘ３を生成するＰＬＬ（フェーズ・ロックド・ループ）回路８０と、ＰＬＬ回路８０で生成された位相の異なる複数のパルスのうち、１つのパルスを選択するセレクタ８４と、セレクタ８４により選択されたパルスの位相をアナログ的に遅延させるアナログ遅延部８５と、アナログ遅延部８５により位相が一定量遅れたパルスと基準となる基本信号（例えば、外部からのクロックＣＬＫ、あるいは、ＰＬＬ回路８０により生成された位相の異なる複数のパルスのうちの１つのパルス（例えばＸ０など））とによりパルス幅を生成するパルス幅生成部８６とを備えている。これにより、所定周波数の基準となるクロック信号に対し、周波数が逓倍された逓倍クロック信号を生成し、生成した逓倍クロック信号から所定の位相遅延した複数のパルスを生成し、デジタル多値画像データの上位ビット信号（例えばＤ４，Ｄ３，Ｄ２の３ビット）に基づき、前記位相の異なる複数のパルスのうちの１つのパルスを選択し、デジタル多値画像データの下位ビット信号（例えばＤ１，Ｄ０の２ビット）に基づき、所望の位相で遅延させて生成したパルスと、前記デジタル遅延手段により生成された複数のパルスのうちの１つのパルスとに基づいてパルス幅信号で半導体レーザの光出力を駆動し、画像変調信号を生成することができる。また、パルス幅生成部８６は、所望の光出力で半導体レーザを駆動する半導体レーザ駆動部とともに、１チップの集積回路に実装されている。
【００８４】
図１７は図１６のパルス幅変調部７１の動作の概略を説明するためのタイムチャートである。図１７においては、説明を簡単にするため、ＰＬＬ回路８０（図１６参照）において、外部からのクロック（画素クロック）ＣＬＫの周波数は４逓倍されるとする。例えば、ＰＬＬ回路８０に入力するクロックＣＬＫの周波数が５０ＭＨｚであるとき、ＰＬＬ回路８０のＶＣＯ８１から出力されるパルス周波数は、５０×４＝２００ＭＨｚになるとする。図１７（ａ）には４逓倍されたクロック（４×ＣＬＫ）が示されている。ここで、この４逓倍されたクロックのデューティは５０％であるとする。これは、４逓倍されたクロック（４×ＣＬＫ）の周波数（例えば２００ＭＨｚ）をさらに逓倍して４００ＭＨｚの周波数のものにすることができるからである。
【００８５】
また、ＰＬＬ回路８０（図１６参照）の分周回路８２（図１６参照）は、ＶＣＯ８１（図１６参照）から出力される４逓倍されたクロック（４×ＣＬＫ）より図１７（ｂ）〜（ｅ）に示すようなπ／４ずつ位相の異なるパルスＸ０〜Ｘ３を生成する。ここで、このパルス幅変調部７１（図１６参照）のパルス幅変調によって画像の階調表現を行なおうとする場合、最上位ビットがＤ４、最下位ビットがＤ０である画像データ（デジタルデータ；階調を表現するデータ）が入力されると仮定し（すなわち、１ドットあたり２５／３２階調のパルス幅変調を行なうと仮定し）、図１６に示すように、上位ビットＤ４、Ｄ３、Ｄ２がセレクタ８４に入力し、下位ビットデータＤ１、Ｄ０がアナログ遅延部８５に入力するとする。この例の場合、セレクタ８４における論理は、セレクタ８４の出力をＰｓとするとき、例えば次式で表わされる。
【００８６】
Ｐｓ＝Ｄ４・（Ｄ３・Ｄ２・Ｘ３＋Ｄ３・＊Ｄ２・Ｘ２＋＊Ｄ３・Ｄ２・Ｘ１＋＊Ｄ３・＊Ｄ２・Ｘ０）＋＊Ｄ４・（Ｄ３・Ｄ２・＊Ｘ３＋Ｄ３・＊Ｄ２＊Ｘ２＋＊Ｄ３・Ｄ２・＊Ｘ１＋＊Ｄ３・＊Ｄ２・＊Ｘ０） …… （１）
すなわち、セレクタ８４からは、データＤ４，Ｄ３，Ｄ２に応じて、Ｘ３，Ｘ２，Ｘ１，Ｘ０，＊Ｘ３，＊Ｘ２，＊Ｘ１，＊Ｘ０のいずれか１つが選択されて出力される。なお、＊は反転記号である。
【００８７】
次に、アナログ遅延部８５においては、下位ビットデータＤ１，Ｄ０に従い、Ｘ０の周期をＴとするとき、Ｄ１・Ｄ０を（３／３２）Ｔ遅延とし、Ｄ１・＊Ｄ０を（２／３２）Ｔ遅延とし、＊Ｄ１・Ｄ０を（１／３２）Ｔ遅延とし、＊Ｄ１・＊Ｄ０を遅延なしとする。いま、例えば、Ｄ４，Ｄ３，Ｄ２，Ｄ１，Ｄ０が（１，１，０，１，０）であるときには、アナログ遅延部８５の出力をＤ_ＰＬＳ とすると、アナログ遅延部８５の出力Ｄ_ＰＬＳ は、図１７（ｆ）に示すように、Ｘ２＋Δ１（Δ１＝（２／３２）Ｔ遅延）となる。そして、パルス幅生成部８６では、例えば、アナログ遅延部８５の出力Ｄ_ＰＬＳ と＊Ｘ０との論理積をとってＵとする。上述の例では、Ｕ＝＊Ｘ０・（Ｘ２＋Δ１）となり、図１７（ｇ）に示すようなパルスＵが得られる。また、パルス幅生成部８６では、Ｄ４・Ｘ０＋Ｕをパルス幅信号ＰＷＭＯＵＴとして最終的に出力する。そして、パルス幅信号ＰＷＭＯＵＴにより、各ＬＤ１２Ｍ，１２Ｃ，１２Ｙ，１２Ｋを点灯駆動する。すなわち、上述の例では、最上位ビットＤ４が１であるので、図１７（ｈ）に示すようなパルス幅信号ＰＷＭＯＵＴを１ドットに出力することができる。
【００８８】
なお、図１７の例では、１ドット内において左に寄せたドットを形成する例で示しているが、セレクタ８４の論理やアナログ遅延部８５の設定により、ドット内において右に寄せたドット形成もできる。
【００８９】
画像形成装置６０を制御する制御部８７は走査光学ユニット１１Ｍ，１１Ｃ，１１Ｙ，１１Ｋを制御し、画像形成装置内のＲＯＭその他の記憶装置に、位置補正データをテーブルデータ８８として登録しておき、このテーブルデータ８８のルックアップにより、制御部８７が制御信号に基づき、制御信号を出力すれば、走査ビームの照射位置をドットごとに主走査方向に調整することができる。また、光量補正データをテーブルデータ８８として登録しておき、このテーブルデータ８８のルックアップにより、制御部８７が制御信号を出力すれば、パルス幅信号ＰＷＭＯＵＴの出力パルス幅を変えることで発光時間を補正し、各ドットの光量を調整することもできる。
【００９０】
図１８は、走査光学ユニット１１Ｍ〜１１Ｋの概念図である。画像信号をもとに生成された画像データは、上述のようにセレクタ８４、アナログ遅延部８５に入力され、パルス幅生成部８６がパルス幅信号ＰＷＭＯＵＴをもとにＬＤ１２Ｍ〜１２Ｋを点灯駆動する。
【００９１】
このように制御部８７により、制御プログラムに基づきテーブルデータ８８を参照して行われる前述の制御について、位置補正データに基づいて行われる各ドットの主走査方向の位置補正、光量補正データに基づいて行われる各ドットの光量補正によって、各画素の位置は主走査方向に揃っていて、かつ、各画素について当該画素を構成する各色の相互の相対位置も揃う。
【００９２】
以上説明したように、個々の画像形成装置６０に搭載される製品としての走査光学ユニット１１Ｍ〜１１Ｋを対象として、感光体ユニット７２Ｍ〜７２Ｋの感光体表面が存在すべき位置で走査ビーム撮像し、このデータから補正データを作成すれば、走査ビームの補正を的確に行なうことができるので、従来に比べて適切なドットの形成を行うことができる。
【００９３】
補正データとして、位置補正データを前記のとおり作成して画像形成装置６０に適用すれば、走査ビームの位置ずれの補正を的確に行なって、カラー画像形成の画像色ずれを低減させることができる。
【００９４】
この場合に、例えば、前述の理想位置に補正する方法で位置補正データを作成すれば、各ドットを本来あるべき適切な位置に形成して、カラー画像形成の画像色ずれを低減させることができる。
【００９５】
補正データとして、光量補正データを前記のとおり作成して画像形成装置６０に適用すれば、従来に比べて適切な走査ビームの光量でドットの形成を行なうことができる。この場合には、前記のとおり、光量の補正を発光強度の補正により行うことも、発光時間の補正により行うことも可能である。
【００９６】
ビーム調整装置のサイズは、画像形成装置の取り外し可能な感光体ユニットの占有スペースに入る大きさとし、取付け部形状は、感光体ユニットの画像形成装置への取付け部と同じものとし、ビーム調整手段とこの取付手段とを一体的に構成することで、画像形成装置への挿入と、画像形成装置に走査光学ユニットを組付けたまま、実使用状態でのビーム調整を行うことができる。
【００９７】
感光体と同じスペース、同じ取り外し操作で調整装置の取付け取り外しができるため、特別な画像形成装置の改造が要らない。画像形成装置内に取付けて、実際の使用状態で、レーザビームにより形成されるドット位置の測定を高精度に行うことができる。また、完成品でのビーム位置調整が可能であるので、工場での調整工程で簡単な作業により作業者が使用して測定することができる。
【００９８】
感光体面上に光走査によるビームのビーム結像状態を測定するビーム測定手段を設ける。また、画像形成装置の制御手段と通信するための通信手段を設ける。また、これらのビーム測定手段と通信手段を制御するための調整制御手段を設ける。これによって、画像形成装置を調整モードにして、ビーム調整装置からの通信により作動状態でレーザー光の発光制御を行わせ、感光体面上でのビームを測定することができる。
【００９９】
画像形成装置を調整モードにして、作動状態でレーザ光の発光制御を調整装置の制御手段と画像形成装置の制御手段との通信で行えるため、特別な回路を調整装置に設ける必要がなく、コスト及び省スペース化することができる。
【０１００】
光走査によるビームを感光体面の略法線方向に配置した光伝達手段に入射させて、伝達されたビーム像を出射端にて、主走査方向に偏向させる偏向手段を設け、前記光伝達手段の出射端に焦点位置がくるように、拡大光学手段を設け、実際に感光面上に露光したビーム像を拡大したものを、二次元エリアセンサで撮像することができる。また、撮像したビーム像から、ビームの光量やビーム位置（主・副）を演算できる。また、主走査方向に撮像手段と光伝達手段と光偏向手段と拡大検出手段からなる測定ヘッドをお互いの位置関係を保ったまま移動させることで、主走査方向のどの位置においても撮像を行える。
【０１０１】
光ファイバを用いた光伝達手段をビーム結像位置に配置し、光偏向手段によって主走査方向に伝達することで、ビーム像の光拡大光学手段と撮像手段を主走査方向に配置することができるため、従来のように、主走査方向と垂直な方向に配置した場合と比べて、対物レンズの焦点距離とそれ自身の大きさと結像長さ、及び、ＣＣＤカメラの大きさによる測定ヘッドの張出しを小さくできるので、調整装置の側面の断面積を小さくすることができ、調整装置を感光体ドラムユニットより、小さくすることができ、画像形成装置内に直接挿入して、ビーム像の測定及び調整を行うことができる。また、光伝達手段、光偏向手段、拡大光学手段、撮像手段からなる測定ヘッドは、一度調整すれば、それぞれの位置関係を変えることなく、固定した状態で、主走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１０２】
光走査によるビームの結像位置に設けた光伝達手段に光ファイバを用い、そのファイバの配列方向を感光体面の略法線方向に配置することで、ビーム像を確実に取得することができる。
【０１０３】
ビームの結像位置に設けた光ファイバにより、その配列方向を感光体面の略法線方向に配置して、ビーム像を取込み、伝達されたビーム像は高効率、低歪みで伝達されるので、ＣＣＤカメラによって確実にビーム位置の測定を行なうことができる。
【０１０４】
ビーム測定手段を感光体回転中心と同一な回転中心で回転できる回転駆動手段を設けている。例えば、カラー画像形成装置などでは、レイアウト上の制約から、走査ビームを折返しミラーを使って、各色の感光体ユニットへ入射させるが、感光体ユニットの形状が同じであっても、入射ビームの感光体への入射位置が異なる場合がある。このとき、前記回転駆動手段を用いて、ビーム測定手段を回転駆動させてビーム入射方向に略一致する方向に配置することができる。
【０１０５】
同一の調整装置を４台用い、カラー画像形成装置において、ビームの入射方向になるように、予め、回転させるだけで、光走査ビームの調整を一度に行うことができる。
【０１０６】
ビーム測定手段によって撮像されたビーム像は、ビーム位置算出手段を用いて、撮像画面内におけるビーム重心位置が算出され、感光体面上でのビーム位置を取得することができる。
【０１０７】
二次元エリアセンサによって撮像されたビーム像からビーム位置を測定することができる。
【０１０８】
ビーム測定手段に、光伝達手段、光偏向手段、拡大光学手段、撮像手段からなる測定ヘッドを、主走査方向に移動する移動ステージにおいて、その移動量を検出するステージ位置検出手段を設けることで、測定系が主走査方向のどの位置にいるかを正確に測定することができる。また、このステージ位置と前記撮像手段内のビーム位置を加算することで、撮像したビームの主走査方向の絶対位置を取得することができる。
【０１０９】
二次元エリアセンサによって測定されたビーム位置と測定ヘッドの主走査方向の位置を演算することにより、ドットの主走査方向の絶対位置を測定することができる。
【０１１０】
ビーム測定手段によって撮像されたビーム像は、ビーム光量算出手段を用いて、撮像画面内におけるビームの光量分布が算出され、感光体面上でのビームの光量分布を取得することができ、このデータに基づいて、特定の閾値をもとに主・副ビーム径を算出することもできる。
【０１１１】
二次元エリアセンサによって撮像されたビーム像からビーム光量分布を測定することができる。
【０１１２】
ビーム測定手段によって取得したビーム位置データとステージ位置データを記憶する記憶手段を設け、このデータから、位置補正データ演算手段を用いて、ドットの位置ずれ補正データを算出することができる。
【０１１３】
画像形成装置で演算してドット位置ずれ補正データを求める必要がないため、画像形成装置に負荷がかからないので、コストアップにもつながらない。
【０１１４】
ビーム測定手段によって取得したビーム光量データを記憶する記憶手段を設け、このデータから、光量補正データ演算手段を用いて、ビーム光量補正データを算出することができる。
【０１１５】
画像形成装置で演算して光量補正データを求める必要がないため、画像形成装置に負荷がかからないので、コストアップにもつながらない。
【０１１６】
従来例では、取得した二次元受光センサーアレイからの信号を画像形成装置内で演算して、光束位置ずれ補正データを求めているため、装置に演算手段を備える必要があり、コスト高になるという不具合がある。また、通信手段を用いて、別の装置で演算させた場合でも、二次元受光センサーアレイからのデータ量が膨大なため、通信時間に多くの時間を費やし、高速に処理できないという不具合もある。
【０１１７】
本実施例の調整制御手段の出力手段は、取得した各データを外部の汎用の記憶手段付き演算装置に出力し、そこで、位置ずれ補正量、及び、ビーム光量補正量を演算させる。そして、演算結果を再び、入力手段を用いて入力する。すなわち、ドットの位置ずれ補正データ、及び、ビーム光量補正データを外部の演算装置を利用して作成することができる。
【０１１８】
画像形成装置で演算してドットの位置ずれ補正データ、及び、ビーム光量補正データを求める必要がないため、画像形成装置に負荷がかからない。また、外部の汎用の記憶手段付き演算装置で演算させるためビーム調整装置に負荷がかからない。また、コストアップにならない。
【０１１９】
調整制御手段は、画像形成装置の制御手段と通信して走査同期信号を取得して、これをもとに位相遅れ回路により、所定時間遅らせた外部トリガ信号を生成させる。ＣＣＤカメラを外部トリガからの信号により撮像する際に、撮像のタイミングが、カメラの水平同期信号のタイミングに依存することなく、走査ビームが感光体面上を一走査する期間に必ずシャッターが開いている状態にして撮像することができる。
【０１２０】
ＣＣＤカメラを外部トリガからの信号により撮像する際に、カメラの水平同期信号のタイミングに依存することなく、走査ビームを確実に撮像することができる。
【０１２１】
調整制御手段は転送手段を用いて、作成したドットの位置ずれ補正データ、及び、ビーム光量補正データを画像形成装置のＬＤ発光パターン生成手段に転送し、記憶させることができる。
【０１２２】
ドットの位置ずれ補正データ、及び、ビーム光量補正データを画像形成装置のＬＤ発光パターン生成手段に転送し、記憶させることができ、ＬＤから補正された発光光量で、かつ、補正されたタイミングでビームを出射させることができるので、これにより、感光体面上に走査ビームにより形成されるドットが適切な位置に適切な光量にすることができる。
【０１２３】
ビーム調整装置を用いて、画像形成装置のドットの位置ずれとビーム光量を調整することができる。これにより高画質なカラー画像形成装置を提供することができる。
【０１２４】
また、走査光学ユニットで使われているポリゴンミラーの回転精度（ジッター）に起因する等速性誤差によるもの、ポリゴンミラーの長時間の回転に伴う軸受等からの発熱によるもの、ｆθレンズやミラーの形状精度やその取付位置不良によるもの、走査光学ユニット自体の取付誤差によるもの、環境変化（温度、湿度等の変化）による装置フレーム変形によるもの、などによって生じるドット位置ずれ、及び、光量変動を、実際の使用条件で正確に測定して、それぞれの補正データを生成し、ＬＤ発光パターン生成手段に転送し記憶させることで、感光体上に照射される光書込みビームの位置、及び、光量を補正することができる。
【０１２５】
図３は本発明に係る第２実施例のビーム調整装置を示す概略構成図である。
図３では、第１実施例のビーム調整装置１０における測定ヘッド２０の別の構成を示している。なお、測定ヘッド２０以外の構成は、第１実施例と同様であるので、その詳細な説明は省略している。
【０１２６】
図３に示すように、測定ヘッド２０は、撮像手段としての二次元エリアセンサ２１から構成されている。測定ヘッド２０を主走査方向に移動させる手段として移動ステージ２５を設ける。そして、移動ステージ２５の主走査方向の位置は、第１実施例と同様に、位置検出ヘッド２６と位置検出スケール２７から、ステージ位置検出部４４（図２参照）によって検出される。これにより、走査ビームの位置を、二次元エリアセンサ２１の画面内の位置と、測定ヘッド２０の位置から測定できる。また、ビーム光量も測定することができる。
【０１２７】
従来例では、二次元受光センサーアレイは感光体の有効走査幅より長いものを用意する必要があるため、検出部に要するコストが非常に高いものになるという不具合がある。また、一般的に、これだけの検出エリアを持つ二次元センサーアレイの画素サイズは、１０×１０μｍ以上あり、位置の検出分解能をこれ以上あげることができない。また、画素ピッチの整列精度を考慮すると、このセンサによる光束位置ずれの測定精度は１０μｍよりあげることは困難であるという不具合もある。
【０１２８】
本実施例によれば、光走査によるビームを感光体面の略法線方向に配置した撮像手段として、例えば二次元エリアセンサ２１を用いて撮像したビーム像から、ビームの光量や画面内の重心位置をもとに計算したビーム位置（主・副）を演算でき、実際に感光面上のどの位置にビームが露光されたかを算出することができる。また、主走査方向に撮像手段を移動させる移動手段を設けることで、主走査方向のどの位置においても撮像を行える。
【０１２９】
ビームの結像位置に撮像手段として、例えば、二次元エリアセンサを設け、撮像手段を含めた測定ヘッドを主走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１３０】
図４は本発明に係る第３実施例のビーム調整装置を示す概略構成図である。
図４では、第１実施例のビーム調整装置１０における測定ヘッド２０のさらに別の構成を示している。なお、測定ヘッド２０以外の構成は、第１実施例と同様であるので、その詳細な説明は省略している。
【０１３１】
図４に示すように、測定ヘッド２０は、光伝達手段２２と、撮像手段としての二次元エリアセンサ２１とから構成されている。測定ヘッド２０を主走査方向に移動させる手段として移動ステージ２５を設ける。そして、移動ステージ２５の主走査方向の位置は、第１実施例と同様に、位置検出ヘッド２６と位置検出スケール２７から、ステージ位置検出部４４によって検出される。これにより、走査ビームの位置を、二次元エリアセンサ２１の画面内の位置と、測定ヘッド２０の位置から測定できる。また、ビーム光量も測定することができる。このとき、光伝達手段２２に、像を拡大して伝達することが可能なテーパファイバオプティクスプレートを使用している。これにより、ビーム像を拡大して二次元エリアセンサ２１で撮像することができ、走査ビームの位置や光量の測定精度を高めている。
【０１３２】
光走査によるビームを感光体面の略法線方向に配置した光伝達手段に入射させて、途中で拡大されたビーム像が出射端に伝達され、実際に感光面上に露光したビーム像を拡大したものを、二次元エリアセンサで撮像することができる。上記第２実施例と同じく、撮像したビーム像から、ビームの光量やビーム位置（主・副）を演算できる。また、主走査方向に光伝達手段と撮像手段からなる測定ヘッドを移動させることで、主走査方向のどの位置においても撮像を行える。
【０１３３】
走査光学系では、有効書込み幅の端部で走査ビームは斜めに感光体に入射されるため、対物レンズを用いて拡大検出する場合、開口数（Ｎ．Ａ）の関係で、鏡筒でビームがけられてしまうので、対物レンズの向きを変える必要があったが、光ファイバを用いた光伝達手段を用いた場合、ビーム結像位置に配置するだけで、感光体と等価な位置でのビーム像を確実に取得でき、さらに、光伝達手段内で拡大検出することも可能となる。また、光伝達手段と撮像手段を含めた測定ヘッドを主走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１３４】
図７は本発明に係る第４実施例のビーム調整装置に備える測定ヘッドの構成例を示す図である。
図７では、第１実施例のビーム調整装置１０における測定ヘッド２０のさらに別の構成を示している。なお、測定ヘッド２０以外の構成は、第１実施例と同様であるので、その詳細な説明は省略している。
【０１３５】
図７に示すように、第４実施例の測定ヘッド２０は、光伝達手段と光偏向手段とをＬ字型光ファイバ３３で構成した。このように、ビームの結像位置（感光体面上Ｒ）にＬ字型光ファイバ３３を設けることにより、第１実施例の光伝達手段と光偏向手段との機能を合わせて利用することができるので、部品点数を削減することができる。
【０１３６】
光走査によるビームの結像位置に設けた光伝達手段とそこでのビーム像を主走査方向に偏向させる光偏向手段として、Ｌ字型の光ファイバを用いることで、感光体面上のビーム像を主走査方向に偏向させて取得することができる。
【０１３７】
ビームの結像位置に設けたＬ字型光ファイバにより、光伝達手段と光偏向手段の機能を合わせて利用することができるので、部品点数を削減することができる。
【０１３８】
以上のビーム調整装置は、レーザビームプリンタ、レーザファクシミリ等の画像形成装置に用いることができ、この画像形成装置における走査光学ユニットのレーザビームの書込み位置や光量を測定し、補正データを作成し反映させることで、その書込み位置や光量の調整を行うことができ、ビーム補正データ作成方法、カラー画像形成装置、プログラム、記憶媒体及び印刷物にも応用できる。
なお、本発明は上記実施例に限定されるものではない。即ち、本発明の骨子を逸脱しない範囲で種々変形して実施することができる。
【０１３９】
【発明の効果】
以上説明したように、請求項１、１８に記載された発明によれば、感光体ユニットが画像形成装置内に占有するスペース内に、画像形成装置側取付手段を介して、画像形成装置用ビーム調整装置の取付け取り外しができるため、特別な画像形成装置の改造が不要である。また、このビーム調整装置を画像形成装置内に取付けて、実際の使用状態で、レーザビームにより形成されるドット位置及びビーム光量の測定を高精度に行うことができる。また、完成品でのビーム位置及びビーム光量の調整が可能であるので、工場での調整工程で簡単な作業により作業者が使用して測定することができる。
【０１４０】
また、請求項２に記載された発明によれば、感光体と同じスペース、同じ取り外し操作で画像形成装置用ビーム調整装置の取付け取り外しができるため、特別な画像形成装置の改造が不要である。画像形成装置用ビーム調整装置を画像形成装置内に取付けて、実際の使用状態で、レーザビームにより形成されるドット位置の測定を高精度に行うことができる。また、完成品でのビーム位置調整が可能であるので、工場での調整工程で簡単な作業により作業者が使用して測定することができる。
【０１４１】
また、請求項３に記載された発明によれば、画像形成装置を調整モードにして、作動状態でレーザ光の発光制御を調整装置の制御手段と画像形成装置の制御手段との通信で行えるため、特別な回路を調整装置に設ける必要がなく、コスト及び省スペース化することができる。
【０１４２】
また、請求項４に記載された発明によれば、ビームの結像位置に撮像手段として、例えば、二次元エリアセンサを設け、撮像手段を含めた測定ヘッドを光走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１４３】
また、請求項５に記載された発明によれば、光伝達手段によりビームの結像位置のビーム像を拡大して伝達できるので、走査ビームの位置や光量の測定精度を高めることができる。また、光伝達手段と撮像手段を含めた測定ヘッドを光走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１４４】
また、請求項６に記載された発明によれば、測定ヘッドの張出しを小さくできるので、調整装置の側面の断面積を小さくすることができ、ビーム調整装置を感光体ユニットより、小さくすることができ、画像形成装置内に直接挿入して、ビーム像の測定及び調整を行うことができる。また、光伝達手段、光偏向手段、拡大光学手段および撮像手段からなる測定ヘッドは、一度調整すれば、それぞれの位置関係を変えることなく、固定した状態で、主走査方向に移動させることで、有効書込み幅全域での測定することができる。
【０１４５】
また、請求項７に記載された発明によれば、ビームの結像位置に設けた光ファイバにより、その配列方向を感光体面の略法線方向に配置して、ビーム像を取込み、伝達されたビーム像は高効率、低歪みで伝達されるので、撮像手段によって確実にビーム位置の測定を行なうことができる。
【０１４６】
また、請求項８に記載された発明によれば、ビームの結像位置に設けたＬ字型光ファイバにより、光伝達手段と光偏向手段との機能を合わせて利用することができるので、部品点数を削減することができる。
【０１４７】
また、請求項９に記載された発明によれば、同一のビーム調整装置を４台用い、カラー画像形成装置において、ビームの入射方向になるように、予め、回転させるだけで、光走査ビームの調整を一度に行うことができる。
【０１４８】
また、請求項１０に記載された発明によれば、撮像手段によって撮像されたビーム像からビーム位置算出手段によりビーム位置を測定することができる。
【０１４９】
また、請求項１１に記載された発明によれば、撮像手段によって測定されたビーム位置と測定ヘッドの主走査方向の位置を演算することにより、ドットの光走査方向の絶対位置を測定することができる。
【０１５０】
また、請求項１２に記載された発明によれば、撮像手段によって撮像されたビーム像からビーム光量分布を測定することができる。
【０１５１】
また、請求項１３に記載された発明によれば、画像形成装置で演算してドット位置ずれ補正データを求める必要がないため、画像形成装置に負荷がかからないので、コストアップにもつながらない。
【０１５２】
また、請求項１４に記載された発明によれば、画像形成装置で演算して光量補正データを求める必要がないため、画像形成装置に負荷がかからないので、コストアップにもつながらない。
【０１５３】
また、請求項１５に記載された発明によれば、画像形成装置で演算してドットの位置ずれ補正データ、及び、ビーム光量補正データを求める必要がないため、画像形成装置に負荷がかからない。また、外部の汎用の記憶手段付き演算装置で演算させるためビーム調整装置に負荷がかからない。また、コストアップにならない。
【０１５４】
また、請求項１６に記載された発明によれば、撮像手段で外部トリガからの信号により撮像する際に、撮像手段の水平同期信号のタイミングに依存することなく、走査ビームを確実に撮影することができる。
【０１５５】
また、請求項１７に記載された発明によれば、ドットの位置ずれ補正データ及びビーム光量補正データを画像形成装置のＬＤ発光パターン生成手段に転送し、記憶させることができ、ＬＤから補正された発光光量で、かつ、補正されたタイミングでビームを出射させることができるので、これにより、感光体面上に走査ビームにより形成されるドットが適切な位置に適切な光量にすることができる。
【図面の簡単な説明】
【図１】本発明に係る一実施例としての第１実施例のビーム調整装置の概略構成図である。
【図２】本発明に係る一実施例としての第１実施例のビーム調整装置の概略システム構成図である。
【図３】本発明に係る第２実施例のビーム調整装置を示す概略構成図である。
【図４】本発明に係る第３実施例のビーム調整装置を示す概略構成図である。
【図５】本発明に係る一実施例としての第１実施例のビーム調整装置の概略構成を示す正面図である。
【図６】図５のビーム調整装置の概略側面断面図である。
【図７】本発明に係る第４実施例のビーム調整装置に備える測定ヘッドの構成例を示す図である。
【図８】本発明に係る一実施例としての第１実施例のビーム調整装置におけるビーム像の検出タイミングを示したタイミングチャートである。
【図９】本発明に係る一実施例としての第１実施例のビーム調整装置における測定フローチャートである。
【図１０】本発明に係る一実施例としての第１実施例のビーム調整装置におけるＬＤ発光パターン生成部での発光タイミングチャートである。
【図１１】本発明に係る一実施例としての第１実施例のビーム調整装置における、倍率誤差及び走査線曲がり量の測定例を示す図である。
【図１２】本発明のビーム調整装置を用いる、一般的なカラー画像形成装置を示す図である。
【図１３】図１２の画像像形成装置で使用されている感光体ユニットの着脱を示す図である。
【図１４】本発明に係る一実施例としての第１実施例のビーム調整装置における、二次元エリアセンサが撮像したビーム画像を画像処理する様子を示す図である。
【図１５】本発明に係る一実施例としての第１実施例のビーム調整装置における、ドットの測定位置と理想位置との差分から位置補正量を求める工程についての説明図である。
【図１６】本発明に係る一実施例としての第１実施例のビーム調整装置を適用する、画像形成装置の各走査光学ユニットが備えているパルス幅変調装置等の回路構成例を示すブロック図である。
【図１７】図１６のパルス幅変調装置の動作を説明するタイミングチャートである。
【図１８】図１２の画像形成装置に備える、走査光学ユニットの概念図を示した図である。
【符号の説明】
１０ ビーム調整装置（ビーム調整手段）
１１ 走査光学ユニット（光書込み光学系）
１２ レーザ光源（レーザダイオード）
１３ 同期検知ＰＤ（フォトダイオード）
１４ ポリゴンミラー
１５ ｆθレンズ
１６ 同期信号
１７ ＬＤ発光パターン生成部
１８ 検出トリガ発生手段
２０ 測定ヘッド２０（ビーム測定手段）
２１ 二次元エリアセンサ（撮像手段）
２２ 光伝達手段
２３ 光偏向手段
２４ 拡大検出手段（拡大光学手段）
２５ 移動ステージ（移動手段）
２６ 位置検出ヘッド
２７ 位置検出スケール
２８ 移動ステージ用ガイド
２９ 移動ステージ用モータ
３０ 側板
３１ａ，３１ｂ 取付手段
３２ 回転手段
３３ Ｌ字型光ファイバ
４０ 調整制御部（調整制御手段）
４１ 画像処理部
４２ ビーム位置算出部
４３ ビーム光量算出部（ビーム光量算出手段）
４４ ステージ位置検出部（ステージ位置検出手段）
４５ データ記憶部（ビーム光量データを記憶する記憶手段）
４６ 通信部（通信手段）
４７ 機構制御部
４８ 位置補整データ演算部（位置補正データ演算手段）
４９ 光量補整データ演算部（光量補整データ演算手段）
５０ 外部演算装置
５１ データ出力部（出力手段）
５２ データ入力部（入力手段）
５３ データ転送部（転送手段）
５４ 表示部
６０ 画像形成装置
７１ パルス幅変調部
７２，７２Ｍ，７２Ｃ，７２Ｙ，７２Ｋ 感光体ユニット
８０ ＰＬＬ回路
８１ ＶＣＯ
８２ 分周回路
８３ 位相比較器または位相周波数比較器
８４ セレクタ
８５ アナログ遅延部
８６ パルス幅生成部
８７ 制御部
８８ テーブルデータ
Ｓ スペーズ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical scanning writing type image forming apparatus that forms an image by exposing an optical writing beam onto a photoreceptor, for example, a position and an amount of an optical writing beam used in a laser beam printer or a laser facsimile. And an adjusting device.
[0002]
[Prior art]
2. Description of the Related Art A scanning optical unit used in an electrophotographic image forming apparatus such as a laser printer, a copying machine, and a facsimile exposes a photosensitive member with a light writing beam. The scanning optical system generally includes a laser light source, a collimating lens, a scanning lens, a mirror, a polygon mirror, and the like, and a point image on the photoconductor is exposed by scanning in a main scanning direction by rotation of the polygon mirror. . In addition, the rotation of the photosensitive drum performs scanning in the sub-scanning direction, and forms an electrostatic latent image. A toner image is formed by attaching toner to the surface of the photosensitive drum on which the electrostatic latent image has been formed and visualizing the toner image. The toner image is transferred and fixed on a transfer sheet, and the toner image is formed on the transfer sheet. Form an image.
[0003]
In a color image forming apparatus provided with the scanning optical unit for the toners of a plurality of colors, the images on the plurality of photoconductors are sequentially superimposed on one sheet of transfer paper to complete the image. Need to match. However, in the apparatus for performing the exposure processing of the photoconductor using the laser beam as described above, the uniformity error caused by the rotation accuracy (jitter) of the polygon mirror used in the scanning optical unit; Due to heat generated from bearings and the like due to the long rotation of the polygon mirror, due to the shape accuracy of the fθ lens and mirror, or due to poor mounting position, due to mounting error of the scanning optical unit itself, environmental change (temperature, humidity, etc.) ), The dot position shift and the light quantity fluctuation caused by the device frame deformation due to the change of the device frame, and the like, it is not possible to form a high quality image.
[0004]
Therefore, in order to align the dot position in the main scanning direction formed by each scanning optical unit in the color image forming apparatus, and to obtain an appropriate light amount, a technique for measuring the dot position and the light amount, and the obtained measured values are used. A technique for correcting the amount of displacement and the amount of light has been developed.
[0005]
For example, as a scanning beam light amount distribution measuring device of a scanning optical system, a device disclosed in JP-A-2002-86795 is conventionally known. In this measuring apparatus, the position of the scanning beam emitted from the scanning optical unit and the unevenness in the amount of light are measured on the photosensitive member surface. In this measuring apparatus, the beam image is enlarged by an objective lens and imaged by a CCD camera in order to increase measurement accuracy.
[0006]
However, this measuring device has a large measuring system due to the focal length of the magnifying optical element for magnifying and detecting the beam, its own size and image forming length, and the size of the CCD camera, and the replaceable photosensitive drum Can not fit in the space where you place. However, unless the enlargement detection is performed to reduce the size of the measurement system, the measurement accuracy cannot be improved. Therefore, in the conventional measuring device, the dot position and the light amount formed by the scanning beam in the scanning optical unit alone can be measured, but have the same measurement accuracy and can be detached to the finished image forming device. There was no beam conditioner.
[0007]
Further, as a laser beam printer and a method of manufacturing the same, a printer disclosed in Japanese Patent Application Laid-Open No. 2002-19184 is known. In this manufacturing method, in the manufacturing process, after assembling the scanning optical unit and the photoconductor, a two-dimensional light receiving sensor array is inserted immediately before the photoconductor to measure the displacement of the light flux in the main scanning direction and the displacement of the light beam in the sub-scanning direction. Based on the measurement data, on / off control of the semiconductor laser and rotation control of the galvanomirror are performed to correct for scan deviation, curvature, tilt, and the like.
[0008]
[Patent Document 1]
JP-A-2002-86795
[Patent Document 2]
JP-A-2002-19184
[0009]
[Problems to be solved by the invention]
However, in the conventional example disclosed in Japanese Patent Application Laid-Open No. 2002-19184, a two-dimensional light receiving sensor array or a reflective hologram member is inserted immediately before the photoconductor to measure the displacement of the light flux in the main scanning direction and the displacement of the light flux in the sub-scanning direction. The measurement cannot be performed at the actual photoconductor position. In the case of the scanning optical system, since the light is incident on the photoconductor at an angle, even if the measurement position is slightly shifted in the optical axis direction, the position measurement error of the light beam becomes large. For example, at the image height at the end, the light beam is inserted 1 mm before in the optical axis direction, and when the incident angle is 20 °, the measured light flux position in the main scanning direction is:
1000 × tan20 ° = 364 μm
And a very large measurement error occurs. In addition, although there is no mention of the insertion method of the two-dimensional light receiving sensor array and its insertion space, it is very difficult to accurately insert and position these in a state where the scanning unit and the photoconductor of the laser printer are assembled. There is also a defect.
[0010]
Further, according to another conventional example disclosed in Japanese Patent Application Laid-Open No. 2002-19184, it is disclosed that the device is shipped in a state where a reflection hologram member and a light beam splitting unit are incorporated in a device (Japanese Patent Application Laid-Open No. 2002-19184). Paragraph [0049] of the description). In this case, first, since the scanning beam always enters the photoconductor through the reflection hologram member, the beam imaging state deteriorates due to the aging of the reflection hologram member and the deformation due to the heat inside the scanning optical unit. Also, the measurement accuracy of the beam position shift measurement itself is expected to deteriorate. Further, not only does the cost of the components constituting these components increase, but also the provision of a space for disposing them inside the product causes a problem that the device becomes larger.
[0011]
Therefore, the present invention provides an image forming apparatus capable of performing beam adjustment in a completed image forming apparatus, easily detaching the image forming apparatus, and measuring at the same level of measurement accuracy as when measuring with a scanning optical unit alone. It is an object of the present invention to provide a beam adjusting device.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to a first aspect of the present invention includes a photoconductor unit that is detachable at an optical scanning writing position of an optical writing beam, and the attaching unit that detachably attaches the photoconductor unit is an image forming apparatus side attachment. A beam adjusting device that adjusts the optical writing beam by using the image forming apparatus including a unit and a photoconductor unit side attaching unit,
Attachment means engageable with the image forming apparatus-side attachment means is provided integrally with the beam adjusting means, and the beam adjusting means is provided in a space occupied by the photoreceptor unit removed from the image forming apparatus. The image forming apparatus is detachably attached to the image forming apparatus-side attaching means via the engageable attaching means, and further, when the beam adjusting means is attached to the space via the attaching means, A beam adjustment device for an image forming apparatus, wherein a measurement position is arranged at a position corresponding to a photoconductor surface of a body unit. With this configuration, it is possible to insert the beam adjusting device for the image forming apparatus into the image forming apparatus and to perform beam adjustment in an actual use state with the scanning optical unit attached to the image forming apparatus.
[0013]
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the engaging means provided on the beam adjusting means has the same structure as the photosensitive unit side attaching means. It is a beam adjusting device for an apparatus. In this configuration, since the mounting means of the beam adjusting device for the image forming apparatus and the mounting means on the photoconductor unit side have the same structure, the beam adjusting apparatus can be inserted into the image forming apparatus by the same operation as the photoconductor unit, and the image forming apparatus can be scanned. Beam adjustment in an actual use state can be performed with the optical unit attached.
[0014]
According to a third aspect of the present invention, the beam adjustment unit communicates with a beam measurement unit that measures an image forming state of a beam by optical scanning on a photoconductor surface of the photoconductor unit, and a control unit of the image forming apparatus. 3. A beam adjusting device for an image forming apparatus according to claim 1, further comprising a communication unit for controlling the beam measuring unit and the communication unit. . With this configuration, the image forming apparatus is set in the adjustment mode, the light emission control of the laser light is performed in the operating state by the communication from the beam adjustment apparatus, and the beam on the photoconductor surface can be measured.
[0015]
According to a fourth aspect of the present invention, the beam measuring means includes an imaging means disposed at an image forming position of the beam by the optical scanning on the photoconductor surface, and a movement for moving the imaging means in the optical scanning direction. 4. A beam adjusting device for an image forming apparatus according to claim 3, further comprising: In this configuration, as an imaging unit in which a beam by optical scanning is arranged in a substantially normal direction of the photoconductor surface, for example, from a beam image imaged using a two-dimensional area sensor, based on a light amount of the beam and a position of a center of gravity in a screen. The calculated beam position (main / sub) can be calculated, and the actual position on the photosensitive surface where the beam has been exposed can be calculated. Further, by providing a moving unit for moving the imaging unit in the optical scanning direction, imaging can be performed at any position in the optical scanning direction.
[0016]
Also, in the invention according to claim 5, the beam measuring means includes a light transmitting means for enlarging and transmitting a beam image at an image forming position of the beam by optical scanning on the photoconductor surface, and an emission surface of the light transmitting means. 4. The beam adjusting device according to claim 3, further comprising: an imaging unit configured to capture an image; and a moving unit configured to move the light transmitting unit and the imaging unit in a direction of the optical scanning. 5. is there. In this configuration, the beam by the optical scanning is made incident on the light transmitting means, and the beam image enlarged on the way is transmitted to the emission end, and the enlarged beam image actually exposed on the photosensitive surface is taken by the imaging means. Images can be taken. Further, the light amount and beam position (main / sub) of the beam can be calculated from the captured beam image. In addition, by moving the measuring head including the light transmitting unit and the imaging unit in the main scanning direction, imaging can be performed at any position in the main scanning direction.
[0017]
Further, according to a sixth aspect of the present invention, the beam measuring means is disposed at an image forming position of the beam by the optical scanning on the photoreceptor surface, and a light transmitting means for transmitting the beam image; Light deflecting means for deflecting the light beam, magnifying optical means for enlarging the beam image to form an image on an image forming surface, imaging means provided on the image forming surface, the light transmitting means, and the light deflecting device. 4. A beam adjusting apparatus for an image forming apparatus according to claim 3, further comprising a moving unit for moving the optical unit and the imaging unit in the light scanning direction. In this configuration, the light amount and the beam position (main / sub) of the beam can be calculated from the captured beam image. In addition, by moving the measuring head including the imaging unit, the light transmitting unit, the light deflecting unit, and the enlargement detecting unit in the optical scanning direction while maintaining the mutual positional relationship, the imaging can be performed at any position in the optical scanning direction.
[0018]
The invention according to claim 7 is characterized in that the light transmitting means is constituted by an optical fiber bundle, and the arrangement direction of the optical fibers of the optical fiber bundle is arranged substantially in the normal direction of the photoconductor. A beam adjusting device for an image forming apparatus according to claim 5. In this configuration, an optical fiber is used as a light transmitting means provided at a beam image forming position by optical scanning, and the arrangement direction of the fiber is arranged in a substantially normal direction of the photoconductor surface, so that a beam image is reliably obtained. be able to.
[0019]
The invention according to claim 8 is characterized in that the light transmitting means and the light deflecting means are constituted by one L-shaped optical fiber, wherein the beam adjusting device for an image forming apparatus according to claim 6 is provided. It is. In this configuration, an L-shaped optical fiber is used as a light transmitting means provided at an image forming position of a beam by optical scanning and a light deflecting means for deflecting the beam image in the main scanning direction. The beam image can be obtained by being deflected in the main scanning direction.
[0020]
According to a ninth aspect of the present invention, the beam measuring means has the same rotation center as the rotation center of the photoreceptor, and rotates the measurement position in the direction of incidence of the beam by optical scanning of the image forming apparatus. 4. The beam adjusting device for an image forming apparatus according to claim 3, further comprising a rotating unit for moving. In this configuration, for example, in a color image forming apparatus or the like, the scanning beam is incident on the photoconductor unit of each color using a folding mirror due to layout restrictions, but even if the shape of the photoconductor unit is the same, Although the incident position of the incident beam on the photoconductor may be different, since the rotating means is used, the measuring position can be arranged in a direction substantially coincident with the beam incident direction by rotating the beam measuring means.
[0021]
The invention according to claim 10 is characterized in that the beam measurement means includes a beam position calculation means for calculating a beam position in an image screen captured by the imaging means. It is a beam adjusting device for a forming apparatus. With this configuration, the beam position of the beam image picked up by the beam measuring unit is calculated in the imaging screen by using the beam position calculating unit, and the beam position on the photoconductor surface can be acquired.
[0022]
The image forming apparatus according to any one of claims 4 to 6, wherein the beam measuring means includes a stage position detecting means for detecting an amount of movement of the moving means. It is a beam adjusting device for an apparatus. In this configuration, the beam measuring means includes a stage position detecting means for detecting a moving amount of a measuring head comprising a light transmitting means, a light deflecting means, an enlarging optical means and an imaging means in a moving stage moving in the main scanning direction. With this arrangement, the position of the measurement system in the optical scanning direction can be accurately measured. Further, by adding the stage position and the beam position in the imaging unit, the absolute position of the imaged beam in the light scanning direction can be obtained.
[0023]
The invention according to claim 12 is characterized in that the beam measuring means includes a beam light quantity calculating means for calculating a light quantity of a beam in an image screen captured by the imaging means. This is a beam adjusting device for an image forming apparatus. With this configuration, for the beam image captured by the beam measuring unit, the light intensity distribution of the beam in the imaging screen is calculated using the beam light intensity calculating unit, and the light intensity distribution of the beam on the photoconductor surface can be obtained. Based on this data, the main and sub beam diameters can be calculated based on a specific threshold.
[0024]
According to a thirteenth aspect of the present invention, the adjustment control means includes a storage means for storing the beam position data and the stage position data acquired while being moved by the movement means, and a position of a dot formed by the optical writing beam. 5. The beam adjustment device for an image forming apparatus according to claim 4, further comprising a position correction data calculation unit that calculates the shift correction data. In this configuration, it is possible to provide storage means for storing the beam position data and the stage position data acquired by the beam measuring means, and to calculate the dot displacement correction data from this data by using the position correction data calculating means. it can.
[0025]
The invention according to claim 14 is characterized in that the adjustment control means includes a storage means for storing beam light quantity data acquired while being moved by the moving means, and a light quantity correction data calculating means for calculating beam light quantity correction data. 4. The beam adjusting device for an image forming apparatus according to claim 3, wherein: In this configuration, a storage unit for storing the beam light amount data acquired by the beam measuring unit is provided, and from this data, the beam light amount correction data can be calculated using the light amount correction data calculation unit.
[0026]
The invention according to claim 15 is characterized in that the adjustment control means includes an output means for outputting beam position data, stage position data, and beam light quantity data acquired while being moved by the movement means, and the optical writing beam. 4. The beam for an image forming apparatus according to claim 3, further comprising: input means for externally acquiring correction data for positional deviation of dots formed by the method and correction data for the light amount of the optical writing beam. An adjusting device. In this configuration, the output unit of the adjustment control unit outputs the acquired data to an external general-purpose arithmetic unit with a storage unit, and calculates the positional deviation correction amount and the beam light amount correction amount. Then, the operation result is input again using the input means. That is, the dot displacement correction data and the beam light amount correction data can be created using an external arithmetic device.
[0027]
Further, in the invention according to claim 16, the adjustment control means communicates with the control means of the image forming apparatus, and controls the imaging means based on an output signal from a synchronization detection means for detecting a timing of scanning a scanning beam. 5. The beam adjusting device for an image forming apparatus according to claim 4, further comprising a detection trigger signal generating means for measuring an imaging timing. In this configuration, the adjustment control unit communicates with the control unit of the image forming apparatus to acquire the scan synchronization signal, and causes the phase delay circuit to generate an external trigger signal delayed for a predetermined time based on the scan synchronization signal. When taking an image of the imaging unit with a signal from an external trigger, the timing of the imaging does not depend on the timing of the horizontal synchronization signal of the imaging unit, and the shutter is always opened during a period in which the scanning beam scans one surface of the photoconductor. Image can be taken while the camera is in the on state.
[0028]
The invention according to claim 17, wherein the adjustment control means is configured to control the LD light emission pattern generation means of the image forming apparatus to correct positional deviation of dots formed by the optical writing beam and to correct beam light amount of the optical writing beam. 4. The beam adjusting device for an image forming apparatus according to claim 3, further comprising a transfer unit for transferring at least one of the beams. With this configuration, the adjustment control unit can transfer the created dot misalignment correction data and the beam light amount correction data to the LD light emission pattern generation unit of the image forming apparatus using the transfer unit, and store the data.
[0029]
The invention according to claim 18, further comprising a detachable photosensitive member unit at an optical scanning writing position of an optical writing beam, wherein the attaching means for detachably attaching the photosensitive unit is an image forming apparatus-side attaching means and a photosensitive unit. A beam adjusting method for adjusting the optical writing beam using the image forming apparatus configured by the side mounting means,
A beam adjusting unit integrally provided with a mounting means engageable with the image forming apparatus-side mounting means is provided in the space occupied by the photoreceptor unit removed from the image forming apparatus. When the beam adjusting means is mounted in the space via the mounting means, the mounting means is detachably attached to the image forming apparatus-side mounting means via a possible mounting means, and corresponds to the photoreceptor surface of the photoreceptor unit. A beam adjustment method for an image forming apparatus, wherein a beam is adjusted by arranging a measurement position at a position to be adjusted. With this configuration, it is possible to insert the beam adjusting device for the image forming apparatus into the image forming apparatus and to perform beam adjustment in an actual use state with the scanning optical unit attached to the image forming apparatus.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a beam adjustment device according to one embodiment of the present invention, FIG. 2 is a schematic system configuration diagram of a beam adjustment device of one embodiment according to the present invention, and FIG. FIG. 6 is a schematic side cross-sectional view of the beam adjusting device of FIG. 5, and FIG. 8 is a timing chart showing a beam image detection timing in the beam adjusting device of one embodiment according to the present invention. FIG. 9 is a measurement flowchart in the beam adjustment device according to one embodiment of the present invention, FIG. 10 is a light emission timing chart in an LD light emission pattern generation unit in the beam adjustment device according to one embodiment of the present invention, and FIG. FIG. 6 is a diagram illustrating a measurement example of a magnification error and a scanning line bending amount in the beam adjustment device according to the embodiment of the present invention.
[0031]
As shown in FIG. 1, the beam adjusting device 10 includes a measuring head 20, a moving stage 25 that moves the measuring head 20 in the main scanning direction, and a position detecting head 26 that detects a stage position of the moving stage 25 (see FIG. 2). ) And a position detection scale 27 fixedly arranged between the pair of side plates 30.
[0032]
The measuring head 20 includes a light transmitting unit 22, a light deflecting unit 23, an enlarging optical unit 24, and a two-dimensional area sensor 21 as an image pickup unit, and their positional relationship is fixedly arranged. A moving stage 25 is provided as means for moving the measuring head 20 in the main scanning direction. The stage position of the moving stage 25 is detected by a position detecting head 26 (see FIG. 2) attached to the moving stage 25 and a position detecting head having a detection width larger than the effective writing width and fixedly arranged between the pair of side plates 30. Using the scale 27, the position of the measuring head 20 in the main scanning direction is detected by the stage position detecting unit 44 (see FIG. 2). The scanning beam emitted from the scanning optical unit 11 which is a scanning optical system as an optical writing optical system is imaged by the two-dimensional area sensor 21 on the photoconductor surface R.
[0033]
As shown in FIG. 2, image data of a beam image captured by the two-dimensional area sensor 21 is processed by an image processing unit 41 provided in the adjustment control unit 40, and transmitted to a beam position calculation unit 42 and a beam light amount calculation unit 43. Thus, beam position data and beam light amount data are calculated, respectively. Thereby, the beam position of the scanning beam in the main scanning direction can be measured from the beam position in the screen of the two-dimensional area sensor 21 and the position in the main scanning direction of the measuring head 20 equipped with them. Also, the beam light quantity can be measured.
[0034]
Here, a general color image forming apparatus using the beam adjusting device of the present invention will be described with reference to FIGS.
FIG. 12 is a diagram showing a general color image forming apparatus using the beam adjusting device of the present invention, and FIG. 13 is a diagram showing attachment and detachment of a photoconductor unit used in the image forming apparatus of FIG.
[0035]
As shown in FIG. 12, a general color image forming apparatus 60 includes photoconductor units 72M, 72C, and 72Y for each of M (magenta), C (cyan), Y (yellow), and K (black). , 72K are provided detachably.
[0036]
Next, the attachment / detachment of the photoreceptor unit will be described with respect to the photoreceptor unit 72M, and the attachment / detachment of the other photoreceptor units 72C, 72Y, and 72K are the same as those of the photoreceptor unit 72M, and a description thereof will be omitted.
[0037]
As shown in FIG. 13, in order to attach and detach the photoconductor unit 72M used in the image forming apparatus 60, the mounting unit 31b of the photoconductor unit 72M is inserted into the mounting unit 31b of the image forming apparatus 30 while being fitted. It can be installed in the space S of the image forming apparatus 60.
[0038]
FIG. 6 shows a side cross section of the beam adjusting device 10 of FIG. 5, but includes the same mounting means 31a as the photoconductor unit, and a space S occupied by the photoconductor unit in the image forming apparatus 60. Since they are substantially the same or smaller, they can be mounted in the space S from which the photoconductor unit 72M (72C, 72Y, 72K) has been removed. The beam adjustment device 10 is configured such that, when the beam adjustment device 10 is mounted in the space S via the attachment means 31a, the beam measurement position of the beam adjustment device 10 coincides with the photoreceptor surface R.
[0039]
With reference to FIG. 2, the system configuration of the beam adjusting device will be described for the case where the scanning optical unit 11 having the optical scanning writing optical system is measured.
As shown in FIG. 2, the scanning optical unit 11 includes a laser diode (hereinafter, referred to as LD) 12 as a laser light source, a synchronization detection PD 13 for detecting a scanning start position of a scanning beam, a polygon mirror 14, and an fθ lens. 15. The transmission and reception of signals to and from the polygon mirror 14 can be performed using a communication unit 46 that is a communication unit of the beam adjustment device 10.
[0040]
Thus, the LD 12 can be driven in accordance with the modulation signal output from the LD light emission pattern generation unit 17 in response to a command from the adjustment control unit 40, and the scanning beam is passed through a lens (not shown) such as a collimator lens to form a polygon. The light is reflected by the mirror 14, and is focused on the surface R of the photoreceptor and scanned in a straight line by a configuration such as the fθ lens 15.
[0041]
Further, the adjustment control unit 40 can select the light emission pattern stored in the image forming apparatus 60 using the communication unit 46. The light emission pattern includes beam modulation data for one scan or more, and a pulse-modulated beam can be emitted from the LD light emission pattern generation unit 17.
[0042]
The emission timing of the scanning beam generated from the LD emission pattern generation unit 17 is phase-synchronized using a synchronization signal 16 obtained by a synchronization detection PD (photodiode) 13 of the scanning optical system.
[0043]
Further, the beam adjustment device 10 takes in the synchronization signal 16 detected by the synchronization detection PD 13 of the scanning optical system from the image forming device 60, and detects the signal whose phase has been adjusted by the detection trigger generation unit 18 by the two-dimensional area sensor 21. It is a trigger. The adjustment control unit 40 includes a mechanism control unit 47 that controls the moving stage 25 of the measurement head 20.
[0044]
As shown in FIG. 5, the measuring head 20 is composed of a light transmitting unit 22, a light deflecting unit 23, an enlarging optical unit 24, and a two-dimensional area sensor 21. Is arranged.
[0045]
The moving stage 25 is guided by two moving stage guides 28 and is driven by a moving stage motor 29. The moving stage guide 28 is a cylindrical sliding guide with respect to a shaft 28 a (see FIG. 6) fixed to both side plates 30 of the adjusting device 10. The space for the moving stage motor 29 can be saved by using a shaft type linear motor.
[0046]
As shown in FIG. 6, a position detection head 26 is mounted on a side surface of the moving stage 25, and a position detection scale 27 is fixedly arranged in the beam adjustment device 10.
The scanning beam emitted from the scanning optical unit 11 is incident on the light transmitting means 22 disposed on the photosensitive member surface R in a direction perpendicular to the writing direction, and the beam image is deflected in the main scanning direction by the light deflecting means. After being enlarged by the enlargement optical unit 24, the image is captured by the two-dimensional area sensor 21. As a result, the beam image can be enlarged and imaged by the two-dimensional area sensor 21, and the measurement accuracy of the position of the scanning beam and the amount of light is improved.
[0047]
In the measuring head 20 of FIG. 1, in the present embodiment, the light transmitting means 22 has a configuration using a fiber optics plate which is an optical device in which optical fibers are bundled. The diameter of this fiber is about several μm, it can transmit light and images with high efficiency and low distortion, and it is not necessary to provide a focal length unlike a lens. It can be arranged perpendicular to the writing direction. In addition, by using a tapered fiber optics plate capable of transmitting an enlarged image as necessary as the light transmission unit 22, the magnification of the magnification detection unit 24 provided at the subsequent stage can be reduced. is there. If a smaller diameter light transmitting means 22 is required, the light may be condensed and transmitted using a photonic crystal or the like.
[0048]
As shown in FIG. 5, the beam adjusting device 10 can rotate the measuring head 20 in the substantially incident direction of the scanning beam by using the rotating unit 32.
[0049]
As shown in FIG. 2, in the beam adjustment device 10, the beam position calculated by the beam position calculation unit 42 in the image processing unit 41 is obtained from the beam image captured by the two-dimensional area sensor 21.
[0050]
FIG. 14 is a diagram illustrating a state in which a beam image captured by a two-dimensional area sensor is image-processed in the beam adjustment device according to the first embodiment as one embodiment according to the present invention.
FIG. 14 shows a state in which a beam image obtained by capturing the scanning beam scanned at a predetermined dot interval by the two-dimensional area sensor 21 is subjected to image processing by the beam position calculation unit 42 in the image processing unit 41. ing. In the image processing in the beam adjusting device 10, a specific light amount threshold is set from the entire beam image, and an image within a white frame is cut out as a beam region. The position of the center of gravity is calculated from the extracted beam region, and the beam position in the main scanning direction and the sub-scanning direction is obtained based on the coordinates.
[0051]
As shown in FIG. 2, the beam adjustment device 10 includes a position detection head 26 attached to a side surface of a movement stage 25 on which the measurement head 20 is mounted, and a position detection scale 27 fixedly arranged in the beam adjustment device 10. Stage position detecting section 44 for detecting the position in the scanning direction.
[0052]
In the beam adjusting device 10, the beam light amount distribution of the beam is calculated by a beam light amount calculation unit 43 in the image processing unit 41 of the beam image captured by the two-dimensional area sensor 21.
[0053]
Further, the beam adjustment device 10 causes the data storage unit 45 to store the beam position data calculated by the beam position calculation unit 42 and the stage position data detected by the stage position detection unit 44. Based on the stored data, the position correction data calculating unit 48 calculates the amount of positional shift of the dots formed by the scanning beam, and calculates the position correction data.
[0054]
Further, the beam adjustment device 10 causes the data storage unit 45 to store the beam light amount data calculated by the beam light amount calculation unit 43. Based on the stored data, the light amount correction data calculation unit 49 calculates the light amount of the scanning beam, and calculates the light amount correction data.
[0055]
Further, the beam adjusting device 10 includes a data output unit 51 that outputs the beam position data, the stage position data, and the beam light amount data stored in the data storage unit 45 to the external arithmetic device 50, and a position calculated by the external arithmetic device 50. It is also possible to provide a configuration including a data input section 52 for inputting correction data and light quantity correction data.
[0056]
FIG. 8A shows a synchronization signal 16 as shown in FIG. Tc in FIG. 8H is a cycle of one scan. FIG. 8B shows that the synchronization signal 16 in FIG. 8A is counted according to the number of surfaces of the polygon mirror 5 to generate a synchronization signal 16 'after the surface selection. FIG. 8C shows an actual LD drive signal. In this embodiment, three short lightings are performed in one scanning period so that dots are printed at both ends and the center on the surface of the photoconductor.
[0057]
FIG. 8D shows an external trigger signal of the two-dimensional CCD camera (two-dimensional area sensor 21), which is generated as a signal whose phase has been adjusted by the detection trigger generating means 18 (see FIG. 2) based on the synchronization signal 16. You. In this embodiment, a signal whose phase is delayed by Td (approximately 310 μsec) from the immediately preceding synchronization signal 16 is generated. Generally, upon receiving an external trigger signal (FIG. 8D), the CCD camera generates a reset signal (FIG. 8F) at the falling timing of the horizontal synchronization signal (FIG. 8E). At the falling timing of the reset signal, the photodiode portion of the CCD camera is discharged (FIG. 8 (g)), and then the electronic shutter (FIG. 8 (h)) is opened to enable the image pickup. The electronic shutter (FIG. 8 (h)) closes the shutter after a set time has elapsed. In this embodiment, the time during which the shutter is open is set to be the same as one scanning cycle Tc (for example, 400 μsec).
[0058]
In this embodiment, the time for which imaging is to be performed is a period for scanning the effective scanning width of 330 mm, and is a period of Te (for example, 280 μsec) in FIG. Since the timing of the external trigger signal (FIG. 8D) to the CCD camera (two-dimensional area sensor 21) and the horizontal synchronization signal (FIG. 8E) are not constant, the external trigger signal (FIG. 8D) ) And the reset signal (FIG. 8 (f)), and the sum of the discharge period Tg (for example, 30 .mu.sec) of the photodiode unit and 110 .mu.sec at the maximum.
[0059]
At the time of measurement, after detecting the synchronization signal of the scanning optical unit 11 (see FIG. 2), it is necessary to bring the two-dimensional CCD camera (two-dimensional area sensor 21) into a state capable of capturing an image in about 10 μsec. Not acceptable. Therefore, as shown in FIG. 8, the detection trigger generating means 18 generates an external trigger signal (FIG. 8D) whose phase is delayed by Td from the synchronization signal 16. By doing so, the shutter is opened regardless of the timing of the external trigger signal (FIG. 8D) of the two-dimensional CCD camera (two-dimensional area sensor 21) and the horizontal synchronization signal (FIG. 8E). The period Te can be reliably included in the period Te during which the scanning beam is irradiated.
[0060]
As shown in FIG. 2, the beam adjustment device 10 can transfer the generated position correction data and light amount correction data from the data transfer unit 53 to the LD light emission pattern generation unit 17 of the image forming apparatus 60.
[0061]
The beam adjusting device 10 mounted in the image forming apparatus 60 measures the position and the light amount of the scanning beam, and transfers correction data calculated from the measured data to the LD light emission pattern generation unit 17 to reflect the correction data. The beam position and the light amount of the image forming apparatus 60 can be adjusted.
[0062]
Next, the measurement operation will be described with reference to the dot position measurement flowchart of this embodiment in FIG.
First, the measuring head 20 is initially moved to a substantially dot forming position on the beam scanning line using the moving stage 25 (step S1). In the first time, the number of times of moving stage pitch feed is set to zero (step S2). Here, the LD 12 is driven according to the modulation signal output from the LD light emission pattern generation unit 17, and the lighting for a time corresponding to one dot is blinked a plurality of times by the selected light emission pattern during one beam scanning period (step S3). ), The beam is made incident on the measuring head 20, and its beam image is obtained (step S4). At the same time, the stage position of the moving stage 25 on which the measuring head 20 is mounted in the main scanning direction is detected (Step S4). The beam position data calculated based on the acquired beam image and the stage position detection data of the moving stage are stored in the data storage unit 45 (step S5).
[0063]
When the measurement at one measurement position is completed, the measurement head 20 is moved to the next dot formation position using the movement stage 25 (step S2), and the LD light emission pattern generation unit 17 synchronizes with the synchronization signal 16 Then, the scanning beam is continuously irradiated by the predetermined pattern, and the same measurement is performed at the moved position. At this time, by setting the amount of movement of the measuring head 20 to the dot interval, a beam image can always be captured near the center of the two-dimensional area sensor 21. The movement of the measuring head 20 and the measurement are repeated over the entire effective writing width to complete all the measurements. The measurement results of the dot positions can be displayed on the display unit 54 as the respective displacement amounts.
[0064]
FIG. 10 is a diagram illustrating an example of a light emission timing chart in the LD light emission pattern generation unit 17 of the present embodiment.
FIG. 10 (a) shows an LD basic signal, and a certain time width is used to ensure that the synchronization detection PD 13 serving as a scanning synchronization signal detecting unit receives light in order to obtain a synchronization signal 16 which is a scanning start position of a scanning beam. To cause the LD 12 to emit light. FIG. 10B shows a synchronization signal 16 obtained from an output signal from the synchronization detection PD 13. The signal is phase-synchronized by a PLL (Phase Locked Loop) circuit by the scanning synchronization signal detecting means, and the signal whose phase has been adjusted as the pixel clock signal (FIG. 10C) of the scanning optical system at the falling timing of FIG. Generate. The signal (FIG. 10D) is a counter value driven by the pixel clock signal, and the counter is reset to 0 by the synchronizing signal 16, and the actual LD 12 (see FIG. 2) is used by using the counter value. Is controlled. That is, a beam is accurately emitted to a target writing position in the main scanning direction. The signal (FIG. 10E) is a signal that actually drives the LD 12 according to a predetermined pattern set by the adjustment control unit 40. For example, in FIG. 10, a light emission interval Tb (FIG. 10E) is set as a quaternary counter. In this manner, the light emission interval Tb (FIG. 10E) of the dot can be set arbitrarily. Since the timing of the LD drive signal in FIG. 10E is precisely synchronized with the synchronization signal 16, the reproducibility of the dot position on the surface to be scanned can be remarkably improved. For example, Ta in FIG. 10C is the cycle of one pixel, and at the photosensitive member surface position R (see FIG. 2), the effective writing width is 330 mm, the writing density is equivalent to 600 dpi, the scanning cycle is 400 μsec, and the effective scanning width is 400 μsec. If the scanning period rate is 70%,
Ta = 400 × 0.7 × 10−6 / (330 × 600 / 25.4) = 3.6 × 10−8 sec = 36 nsec. The pixel clock (c) has a cycle of 1/36 (nsec) = 27.8 MHz.
[0065]
FIG. 11 is a diagram showing a measurement example of a magnification error and a scanning line bending amount in the beam adjusting device of the first embodiment as one embodiment according to the present invention.
As shown in FIG. 11, the LD light emission pattern generation unit 17 (see FIG. 2) takes in the synchronization signal 16 by the synchronization detection PD 13 as a scanning synchronization signal detecting unit, and synchronizes with this signal to convert the beam to one dot. A light emission mode is provided in which light emission for only time can be repeatedly emitted at regular time intervals during one scanning period. For example, as shown in FIG. 11, the light is turned on every four pixels. In the case of 600 dpi, the pitch between dots is 169.3 μm. The scanning optical unit repeats the movement of the dots hit on the surface to be scanned at the predetermined intervals by using the moving stage 25 (see FIG. 2) by the dot interval calculated from the scanning speed of the scanning optical system and the light emission time interval. In the effective writing width of 11 (see FIG. 2), each beam position data is stored in the data storage unit 45 (see FIG. 2), and each beam position is calculated using the beam position calculation unit 42 (see FIG. 2). I do.
[0066]
FIG. 11 shows beam positions in the main scanning direction and the sub-scanning direction of a plurality of dots that are formed at a constant interval (in FIG. 11, dr1 = dr2 = dr3) in the effective writing width of the scanning optical unit 11 (see FIG. 2). Based on the data, a deviation amount from a predetermined (designed) position, a local magnification error based on a distance between two adjacent points, and a scanning line bending of a scanning optical system based on sub-scanning direction measurement data. It is a schematic diagram of calculating an amount. For example, based on the measurement results at four locations in the measurement ranges A, B, C, and D, the displacement amounts dx0, dx1, dx2, and dx3 at each location, the local pitch intervals dp1, dp2, and dp3, and the scanning line bend. The quantity dy can be obtained respectively. The measurement result of the dot position can display the local magnification error and the amount of scan line bending on the display unit 54 (see FIG. 2).
[0067]
As shown in FIG. 12, in the image forming apparatus 60, as described above, the photoconductor units 72M, 72C, 72Y, and 72K include the respective colors of M (magenta), C (cyan), Y (yellow), and K (black). It is provided detachably for each. Further, the image forming apparatus 60 includes a charger (not shown) for uniformly charging the surface of each of the photoreceptor units 72M, 72C, 72Y, and 72K, and exposes and scans the surface of the corresponding photoreceptor to form an electrostatic latent image. A developing device that holds a developer containing a toner of a predetermined color and applies a developing bias between the scanning optical units 11M, 11C, 11Y, and 11K (see FIG. 18) for forming images. (Not shown) and a transfer device (not shown) that applies a transfer bias between the corresponding photoconductor units 72M, 72C, 72Y, and 72K disposed on the back side of the conveyance surface of the conveyance transfer belt serving as a polymerization device. ), A cleaner (not shown) for removing toner remaining on the surface of each of the photoconductor units 72M, 72C, 72Y, 72K after the transfer of the toner image, and each of the photoconductor units 72M, 72C, 7 Y, discharger to sweep the charge of 72K surface (not shown) and the like are arranged.
[0068]
In the above-described configuration, the toner images of each color of M, C, Y, and K formed on each of the photoconductor units 72M, 72C, 72Y, and 72K by a well-known electrophotographic process are conveyed to each of the photoconductor units. The images are sequentially transferred by a transfer unit onto a sheet moving to 72M, 72C, 72Y, 72K.
[0069]
As a result, the toner images of the respective colors M, C, Y, and K are superimposed and transferred on the sheet, thereby forming a color image. Hereinafter, an example of the image forming apparatus 60 that handles four colors of M, C, Y, and K will be described.
[0070]
In this example, the scanning beams output from the scanning optical units 11M, 11C, 11Y, and 11K are measured for the image forming apparatus 60, and predetermined correction data is created from the results. The step of calculating is described.
[0071]
As shown in FIG. 2, the beam position calculation unit 42 and the beam light amount calculation unit 43 of the beam adjustment device 10 calculate each scanning optical unit 11M from the light amount distribution data of the two-dimensional image data obtained by imaging with the measurement head 20. , 11C, 11Y, and 11K (see FIG. 18), and the beam light amounts.
[0072]
The position correction data calculator 48 calculates the beam scanning position of each of the scanning optical units 11M, 11C, 11Y, and 11K in the main scanning direction from the data of the beam scanning position, and further calculates the positions of the scanning beams detected at all image heights. From the data, a displacement amount from a predetermined position is calculated. The scanning beam position in the scanning area of each of the scanning optical units 11M, 11C, 11Y, and 11K is set at the position of the moving stage 25 in the scanning direction detected by the stage position detection unit 44, of each of the scanning optical units 11M, 11C, 11Y, and 11K. It can be obtained by adding the positions of the two-dimensional area sensor 21 in the screen.
[0073]
Further, the light quantity correction data calculation unit 49 obtains an error in the light quantity of each dot with reference to a predetermined light quantity from the light quantity of the scanning beam detected at the image height from the light quantity data of the scanning beam.
[0074]
Next, in the step of generating correction data for correcting the scanning beam output from each of the scanning optical units 11M, 11C, 11Y, and 11K, the generation of position correction data for correcting the scanning position of the scanning beam will be described as an example. A case in which the amount of deviation from the ideal position is corrected will be described.
[0075]
FIG. 15 is an explanatory diagram of a step of obtaining a position correction amount from a difference between a dot measurement position and an ideal position in the beam adjustment device according to the first embodiment as one embodiment of the present invention.
[0076]
As shown in FIG. 15, the ideal positions of the i-th (i = 1, 2, 3,...) Pixel in the main scanning direction and the sub-scanning direction are (XOi, YOi), and M, M in the main scanning direction and the sub-scanning direction. Assuming that the measurement positions of C, Y, and K are (XMi, YMi), (XCi, YCi), (XYi, YYi), and (XKi, YKi), the position correction amount of each of the colors M, C, Y, and K ( ΔXMi, ΔYMi), (ΔXCi, ΔYCi), (ΔXYi, ΔYYi), (ΔXKi, ΔYKi) are calculated as follows. That is, the position correction amount is obtained from the difference between the measurement position and the ideal position.
[0077]

[0078]
With the above-described method, the position correction amounts (ΔXMi, ΔYMi), (ΔXCi, ΔYCi), (ΔXYi, ΔYYi), and (ΔXKi, ΔYKi) of the dots of the respective colors M, C, Y, and K are obtained.
[0079]
When there is an error in the light amount of the scanning beam, correction data for correcting the error is generated by the light amount correction data calculation unit 49 for each pixel. That is, light amount correction data for correcting the light emission intensity or the lighting time width is created by comparing the light amount distribution of the scanning beam with the peak light amount value obtained from the design value and the dot size.
[0080]
When the position correction data and the light amount correction data are obtained as described above, the LD light emission pattern generation unit 17 sets a modulation signal obtained by correcting the test writing pattern used first with the position correction data and the light amount correction data. Then, a scanning beam is output, the position of the photoconductor is scanned again, and the measurement is performed by the measuring head 20, thereby conducting a test for confirming the effect. After confirming the effect, finally, correction data including the position correction data and the light amount correction data is obtained.
[0081]
In this way, correction data is obtained for each of the scanning optical units 11M, 11C, 11Y, and 11K of the image forming apparatus 60, and the obtained correction data is registered in advance in the storage device of the corresponding image forming apparatus 60 as table data. Keep it. Then, the image forming apparatus 60 forms an image while correcting the output of the scanning beam using the correction data. Hereinafter, how the image forming apparatus 60 performs control using the correction data will be described.
[0082]
FIG. 16 is a block diagram illustrating an example of a circuit configuration of a pulse width modulation device and the like included in each scanning optical unit of an image forming apparatus to which the beam adjustment device according to the first embodiment as one embodiment according to the invention is applied. It is.
[0083]
FIG. 16 illustrates a circuit configuration example of the pulse width modulation unit 71 and the like included in each of the scanning optical units 11M to 11K of the image forming apparatus 60. 16 has a VCO (Voltage Controlled Oscillator) 81, a frequency dividing circuit 82, a phase comparator or a phase frequency comparator 83, and a plurality of pulses having different phases, for example, X0, X1, X2, A PLL (phase locked loop) circuit 80 for generating X3, a selector 84 for selecting one pulse from among a plurality of pulses having different phases generated by the PLL circuit 80, An analog delay unit 85 for delaying the phase in an analog manner; a pulse whose phase is delayed by a predetermined amount by the analog delay unit 85 and a reference basic signal (for example, an external clock CLK or a phase generated by the PLL circuit 80). A pulse width generation unit 86 that generates a pulse width using one pulse (for example, X0 or the like) among a plurality of pulses different from each other. It is provided. Thereby, a frequency-multiplied clock signal whose frequency is multiplied with respect to a clock signal serving as a reference of a predetermined frequency is generated, a plurality of pulses with a predetermined phase delay are generated from the generated multiplied clock signal, and digital multi-valued image data is generated. One of the plurality of pulses having different phases is selected based on an upper bit signal (for example, three bits D4, D3, and D2), and a lower bit signal (for example, D1 and D0 2) of digital multilevel image data is selected. Bit), the optical output of the semiconductor laser is driven by a pulse width signal based on a pulse generated by delaying at a desired phase and one of a plurality of pulses generated by the digital delay unit. , An image modulation signal can be generated. The pulse width generator 86 is mounted on a one-chip integrated circuit together with a semiconductor laser driver that drives a semiconductor laser with a desired optical output.
[0084]
FIG. 17 is a time chart for explaining an outline of the operation of the pulse width modulation section 71 of FIG. In FIG. 17, for the sake of simplicity, it is assumed that the frequency of an external clock (pixel clock) CLK is multiplied by 4 in PLL circuit 80 (see FIG. 16). For example, when the frequency of the clock CLK input to the PLL circuit 80 is 50 MHz, the pulse frequency output from the VCO 81 of the PLL circuit 80 is assumed to be 50 × 4 = 200 MHz. FIG. 17A shows a clock multiplied by 4 (4 × CLK). Here, it is assumed that the duty of the quadrupled clock is 50%. This is because the frequency (for example, 200 MHz) of the quadrupled clock (4 × CLK) can be further multiplied to a frequency of 400 MHz.
[0085]
The frequency divider 82 (see FIG. 16) of the PLL circuit 80 (see FIG. 16) uses the quadrupled clock (4 × CLK) output from the VCO 81 (see FIG. 16) to output the signals shown in FIGS. Pulses X0 to X3 having different phases by π / 4 as shown in e) are generated. Here, when the gradation of the image is to be expressed by the pulse width modulation of the pulse width modulation unit 71 (see FIG. 16), the image data (digital data; It is assumed that data representing gradation is input (that is, pulse width modulation of 25/32 gradations per dot is performed), and as shown in FIG. 16, the upper bits D4, D3, D2 Are input to the selector 84, and the lower bit data D1 and D0 are input to the analog delay unit 85. In the case of this example, when the output of the selector 84 is Ps, the logic in the selector 84 is represented by the following equation, for example.
[0086]
Ps = D4 · (D3 · D2 · X3 + D3 · * D2 · X2 + * D3 · D2 · X1 + * D3 · * D2 · X0) + * D4 · (D3 · D2 · * X3 + D3 · * D2 * X2 + * D3 · D2 · * X1 + * D3 * D2 * X0) (1)
That is, one of X3, X2, X1, X0, * X3, * X2, * X1, * X0 is selected and output from the selector 84 in accordance with the data D4, D3, D2. * Is an inversion symbol.
[0087]
Next, in the analog delay unit 85, when the cycle of X0 is T according to the lower bit data D1 and D0, D1 · D0 is (3/32) T delay and D1 · * D0 is (2/32) Let T be a delay, * D1 · D0 be a (1/32) T delay, and * D1 * D0 be no delay. Now, for example, when D4, D3, D2, D1, and D0 are (1, 1, 0, 1, 0), the output of the analog delay unit 85 is set to D _PLS Then, the output D of the analog delay unit 85 _PLS Is X2 + Δ1 (Δ1 = (2/32) T delay) as shown in FIG. Then, in the pulse width generation unit 86, for example, the output D of the analog delay unit 85 is output. _PLS And the logical product of * X0 and U. In the above example, U = * X0 · (X2 + Δ1), and a pulse U as shown in FIG. 17G is obtained. Further, the pulse width generation unit 86 finally outputs D4.X0 + U as the pulse width signal PWMOUT. Then, each of the LDs 12M, 12C, 12Y, and 12K is driven to light by the pulse width signal PWMOUT. That is, in the above example, since the most significant bit D4 is 1, the pulse width signal PWMOUT as shown in FIG. 17H can be output for one dot.
[0088]
Although the example of FIG. 17 shows an example in which a dot shifted to the left within one dot is formed, the formation of a dot shifted to the right within a dot may be performed according to the logic of the selector 84 and the setting of the analog delay unit 85. it can.
[0089]
A control unit 87 that controls the image forming apparatus 60 controls the scanning optical units 11M, 11C, 11Y, and 11K, and registers position correction data as table data 88 in a ROM or other storage device in the image forming apparatus. If the control section 87 outputs a control signal based on the control signal by looking up the table data 88, the irradiation position of the scanning beam can be adjusted in the main scanning direction for each dot. Further, the light amount correction data is registered as table data 88, and if the control unit 87 outputs a control signal by looking up the table data 88, the light emission time is changed by changing the output pulse width of the pulse width signal PWMOUT. Correction can be performed to adjust the light amount of each dot.
[0090]
FIG. 18 is a conceptual diagram of the scanning optical units 11M to 11K. The image data generated based on the image signal is input to the selector 84 and the analog delay unit 85 as described above, and the pulse width generation unit 86 drives the LDs 12M to 12K to light up based on the pulse width signal PWMOUT.
[0091]
As described above, the control performed by the control unit 87 with reference to the table data 88 based on the control program is based on the position correction of each dot in the main scanning direction performed based on the position correction data and the light amount correction data. Due to the correction of the light amount of each dot, the positions of the pixels are aligned in the main scanning direction, and the relative positions of the colors constituting the pixels are also aligned for each pixel.
[0092]
As described above, for the scanning optical units 11M to 11K as products mounted on the individual image forming apparatuses 60, scanning beam imaging is performed at positions where the photoconductor surfaces of the photoconductor units 72M to 72K should exist. If the correction data is created from this data, the scanning beam can be accurately corrected, so that a more appropriate dot can be formed as compared with the related art.
[0093]
If the position correction data is created as the correction data as described above and is applied to the image forming apparatus 60, the position deviation of the scanning beam can be accurately corrected, and the image color deviation in color image formation can be reduced.
[0094]
In this case, for example, if the position correction data is created by the above-described method of correcting to the ideal position, each dot can be formed at an appropriate position where it should be, and the image color misregistration of the color image formation can be reduced. .
[0095]
If the light amount correction data is created as the correction data as described above and applied to the image forming apparatus 60, dots can be formed with an appropriate light amount of the scanning beam as compared with the related art. In this case, as described above, the light amount can be corrected by correcting the light emission intensity or the light emission time.
[0096]
The size of the beam adjusting device should be large enough to fit into the space occupied by the removable photoreceptor unit of the image forming apparatus, and the shape of the mounting portion should be the same as the mounting portion of the photoreceptor unit to the image forming device. By integrally configuring the mounting means, it is possible to perform insertion into the image forming apparatus and beam adjustment in an actual use state while the scanning optical unit is attached to the image forming apparatus.
[0097]
Since the adjusting device can be attached and detached in the same space and the same detaching operation as the photoreceptor, no special remodeling of the image forming apparatus is required. Attached in the image forming apparatus, it is possible to measure a dot position formed by a laser beam with high accuracy in an actual use state. In addition, since the beam position of the finished product can be adjusted, the measurement can be performed by an operator using a simple operation in the adjustment process at the factory.
[0098]
A beam measuring unit is provided on the surface of the photoreceptor for measuring a beam imaging state of the beam by optical scanning. Further, a communication unit for communicating with the control unit of the image forming apparatus is provided. Further, an adjustment control unit for controlling the beam measurement unit and the communication unit is provided. Thus, the image forming apparatus is set to the adjustment mode, the light emission control of the laser beam is performed in the operating state by the communication from the beam adjustment apparatus, and the beam on the photoconductor surface can be measured.
[0099]
Since the image forming apparatus is set in the adjustment mode and the emission control of the laser beam can be performed in the operating state by communication between the control means of the adjustment apparatus and the control means of the image forming apparatus, there is no need to provide a special circuit in the adjustment apparatus, and the cost is reduced. In addition, space can be saved.
[0100]
Deflection means for irradiating a beam by optical scanning on light transmission means arranged in a direction substantially normal to the surface of the photoreceptor and deflecting the transmitted beam image at an emission end in a main scanning direction is provided. A magnifying optical means is provided so that the focal position is located at the emission end, and a magnified beam image actually exposed on the photosensitive surface can be captured by the two-dimensional area sensor. Further, the light amount and the beam position (main / sub) of the beam can be calculated from the captured beam image. In addition, by moving the measuring head including the imaging unit, the light transmitting unit, the light deflecting unit, and the enlargement detecting unit in the main scanning direction while maintaining the mutual positional relationship, imaging can be performed at any position in the main scanning direction.
[0101]
By arranging the light transmitting means using an optical fiber at the beam imaging position and transmitting the light in the main scanning direction by the light deflecting means, it is possible to arrange the light magnifying optical means and the imaging means of the beam image in the main scanning direction. Therefore, as compared with the conventional case where the measuring head is arranged in a direction perpendicular to the main scanning direction, the extension of the measuring head due to the focal length of the objective lens, the size of itself and the image forming length, and the size of the CCD camera. Can be reduced, the cross-sectional area of the side surface of the adjusting device can be reduced, the adjusting device can be made smaller than the photosensitive drum unit, and can be directly inserted into the image forming apparatus to measure and adjust the beam image. It can be carried out. In addition, the measuring head including the light transmitting unit, the light deflecting unit, the magnifying optical unit, and the image pickup unit, once adjusted, does not change their respective positional relationships, and is moved in the main scanning direction in a fixed state, Measurement can be performed over the entire effective writing width.
[0102]
By using an optical fiber for the light transmitting means provided at the beam imaging position by the optical scanning and arranging the fibers in a direction substantially normal to the surface of the photoreceptor, a beam image can be reliably obtained.
[0103]
With the optical fiber provided at the beam imaging position, the arrangement direction is arranged in the substantially normal direction of the photoconductor surface, the beam image is captured, and the transmitted beam image is transmitted with high efficiency and low distortion, The beam position can be reliably measured by the CCD camera.
[0104]
Rotation driving means is provided for rotating the beam measuring means at the same rotation center as the rotation center of the photoconductor. For example, in a color image forming apparatus or the like, the scanning beam is incident on the photoconductor unit of each color using a folding mirror due to layout restrictions. However, even if the shape of the photoconductor unit is the same, the scanning beam is exposed. The position of incidence on the body may be different. At this time, the beam measuring means can be rotationally driven using the rotation driving means and arranged in a direction substantially coincident with the beam incident direction.
[0105]
In the color image forming apparatus using four identical adjusting devices, adjustment of the light scanning beam can be performed at once by simply rotating the beam so as to be in the incident direction of the beam.
[0106]
The beam image picked up by the beam measuring means is used to calculate the position of the center of gravity of the beam in the imaging screen using the beam position calculating means, so that the beam position on the photoconductor surface can be obtained.
[0107]
The beam position can be measured from the beam image captured by the two-dimensional area sensor.
[0108]
By providing a beam measuring unit, a light transmitting unit, a light deflecting unit, an enlarging optical unit, and a measuring stage including an imaging unit, a moving stage that moves in the main scanning direction, and a stage position detecting unit that detects a moving amount of the measuring head. The position of the measurement system in the main scanning direction can be accurately measured. Further, by adding the stage position and the beam position in the imaging means, the absolute position of the imaged beam in the main scanning direction can be obtained.
[0109]
By calculating the beam position measured by the two-dimensional area sensor and the position of the measuring head in the main scanning direction, the absolute position of the dot in the main scanning direction can be measured.
[0110]
In the beam image picked up by the beam measuring means, the light quantity distribution of the beam in the imaging screen is calculated using the beam light quantity calculating means, and the light quantity distribution of the beam on the photoconductor surface can be obtained. Based on this, the primary and secondary beam diameters can be calculated based on a specific threshold.
[0111]
The beam light amount distribution can be measured from the beam image captured by the two-dimensional area sensor.
[0112]
A storage unit for storing the beam position data and the stage position data obtained by the beam measuring unit is provided, and from this data, dot displacement correction data can be calculated by using a position correction data calculation unit.
[0113]
Since there is no need to calculate dot position deviation correction data by performing calculations in the image forming apparatus, no load is imposed on the image forming apparatus, which does not lead to an increase in cost.
[0114]
There is provided storage means for storing the beam light quantity data acquired by the beam measuring means, and from this data, beam light quantity correction data can be calculated using light quantity correction data calculation means.
[0115]
Since there is no need to calculate light amount correction data by performing calculations in the image forming apparatus, no load is imposed on the image forming apparatus, and this does not lead to an increase in cost.
[0116]
In the conventional example, since the acquired signal from the two-dimensional light receiving sensor array is calculated in the image forming apparatus to obtain the light flux position shift correction data, it is necessary to provide the apparatus with an arithmetic unit, which increases the cost. There is a defect. Further, even when the calculation is performed by another device using the communication means, there is also a problem that a large amount of data is received from the two-dimensional light receiving sensor array, so that a large amount of time is spent on communication time and high-speed processing cannot be performed.
[0117]
The output means of the adjustment control means of the present embodiment outputs the obtained data to an external general-purpose arithmetic device with a storage means, and calculates the positional deviation correction amount and the beam light amount correction amount there. Then, the operation result is input again using the input means. That is, the dot displacement correction data and the beam light amount correction data can be created using an external arithmetic device.
[0118]
Since there is no need to calculate dot misalignment correction data and beam light amount correction data by performing calculations in the image forming apparatus, no load is imposed on the image forming apparatus. In addition, since the calculation is performed by an external general-purpose calculation device with storage means, no load is applied to the beam adjustment device. Also, the cost does not increase.
[0119]
The adjustment control unit communicates with the control unit of the image forming apparatus to acquire the scan synchronization signal, and causes the phase delay circuit to generate an external trigger signal delayed by a predetermined time based on the scan synchronization signal. When capturing an image of a CCD camera using a signal from an external trigger, the shutter is always opened during a period in which the scanning beam scans one surface of the photoconductor without depending on the timing of the horizontal synchronization signal of the camera. An image can be taken in the state.
[0120]
When capturing an image of a CCD camera with a signal from an external trigger, it is possible to reliably capture an image of a scanning beam without depending on the timing of a horizontal synchronization signal of the camera.
[0121]
The adjustment control unit can transfer the created dot misalignment correction data and the beam light amount correction data to the LD light emission pattern generation unit of the image forming apparatus using the transfer unit and store the data.
[0122]
The dot misalignment correction data and the beam light amount correction data can be transferred to the LD light emission pattern generation means of the image forming apparatus and stored therein, and the beam is emitted at the light emission amount corrected from the LD and at the corrected timing. Can be emitted, whereby the dots formed by the scanning beam on the surface of the photoreceptor can have an appropriate amount of light at an appropriate position.
[0123]
Using the beam adjusting device, it is possible to adjust the dot displacement and the beam light amount of the image forming apparatus. Thus, a high-quality color image forming apparatus can be provided.
[0124]
In addition, the error is caused by a constant velocity error caused by the rotation accuracy (jitter) of the polygon mirror used in the scanning optical unit, the heat generated by bearings and the like due to the long-time rotation of the polygon mirror, the fθ lens and the mirror. Dot position deviation and light amount fluctuation caused by shape accuracy or defective mounting position, mounting error of scanning optical unit itself, device frame deformation due to environmental change (change of temperature, humidity, etc.) Correctly measure under actual usage conditions, generate each correction data, transfer to LD light emission pattern generation means and store it, thereby correcting the position of light writing beam irradiated on photoreceptor and light quantity can do.
[0125]
FIG. 3 is a schematic configuration diagram showing a beam adjusting device according to a second embodiment of the present invention.
FIG. 3 shows another configuration of the measuring head 20 in the beam adjusting device 10 of the first embodiment. Since the configuration other than the measuring head 20 is the same as that of the first embodiment, detailed description thereof is omitted.
[0126]
As shown in FIG. 3, the measuring head 20 includes a two-dimensional area sensor 21 as an imaging unit. A moving stage 25 is provided as means for moving the measuring head 20 in the main scanning direction. Then, the position of the moving stage 25 in the main scanning direction is detected by the stage position detecting unit 44 (see FIG. 2) from the position detecting head 26 and the position detecting scale 27, as in the first embodiment. Thus, the position of the scanning beam can be measured from the position in the screen of the two-dimensional area sensor 21 and the position of the measuring head 20. Also, the beam light quantity can be measured.
[0127]
In the conventional example, since it is necessary to prepare a two-dimensional light receiving sensor array longer than the effective scanning width of the photoconductor, there is a problem that the cost required for the detection unit becomes extremely high. In general, the pixel size of a two-dimensional sensor array having such a detection area is 10 × 10 μm or more, and the position detection resolution cannot be further improved. In addition, when the alignment accuracy of the pixel pitch is considered, there is a problem that it is difficult to increase the accuracy of measuring the light beam position deviation by this sensor to more than 10 μm.
[0128]
According to the present embodiment, as an imaging unit in which a beam by optical scanning is arranged in a direction substantially normal to the surface of the photoconductor, for example, a beam image captured using a two-dimensional area sensor 21 is used to determine the light amount of the beam and the position of the center of gravity in the screen. And the beam position (main / sub) calculated based on the above can be calculated, and it is possible to calculate at which position on the photosensitive surface the beam was actually exposed. In addition, by providing a moving unit that moves the imaging unit in the main scanning direction, imaging can be performed at any position in the main scanning direction.
[0129]
By providing, for example, a two-dimensional area sensor as an imaging unit at the beam imaging position and moving the measuring head including the imaging unit in the main scanning direction, it is possible to perform measurement over the entire effective writing width.
[0130]
FIG. 4 is a schematic configuration diagram showing a beam adjusting device according to a third embodiment of the present invention.
FIG. 4 shows still another configuration of the measuring head 20 in the beam adjusting device 10 of the first embodiment. Since the configuration other than the measuring head 20 is the same as that of the first embodiment, detailed description thereof is omitted.
[0131]
As shown in FIG. 4, the measuring head 20 includes a light transmitting unit 22 and a two-dimensional area sensor 21 as an imaging unit. A moving stage 25 is provided as means for moving the measuring head 20 in the main scanning direction. Then, the position of the moving stage 25 in the main scanning direction is detected by the stage position detecting section 44 from the position detecting head 26 and the position detecting scale 27 as in the first embodiment. Thus, the position of the scanning beam can be measured from the position in the screen of the two-dimensional area sensor 21 and the position of the measuring head 20. Also, the beam light quantity can be measured. At this time, a tapered fiber optics plate capable of transmitting an enlarged image is used for the light transmitting means 22. As a result, the beam image can be enlarged and imaged by the two-dimensional area sensor 21, and the measurement accuracy of the position of the scanning beam and the amount of light is improved.
[0132]
The beam from the optical scanning is made incident on the light transmitting means arranged in a direction substantially normal to the surface of the photoreceptor, and the beam image enlarged on the way is transmitted to the emission end, and the beam image actually exposed on the photosensitive surface is enlarged. Things can be imaged with a two-dimensional area sensor. As in the second embodiment, the light amount and the beam position (main / sub) of the beam can be calculated from the captured beam image. In addition, by moving the measuring head including the light transmitting unit and the imaging unit in the main scanning direction, imaging can be performed at any position in the main scanning direction.
[0133]
In the scanning optical system, the scanning beam is obliquely incident on the photoconductor at the end of the effective writing width. Therefore, when the magnification detection is performed using the objective lens, the beam is transmitted through the lens barrel due to the numerical aperture (NA). It was necessary to change the direction of the objective lens because it would be blurred.However, when using a light transmission means using an optical fiber, simply placing it at the beam imaging position, the beam at a position equivalent to the photoconductor An image can be reliably acquired, and further, magnification detection can be performed in the light transmission unit. In addition, by moving the measuring head including the light transmitting unit and the imaging unit in the main scanning direction, it is possible to perform measurement over the entire effective writing width.
[0134]
FIG. 7 is a diagram showing a configuration example of a measuring head provided in a beam adjusting device according to a fourth embodiment of the present invention.
FIG. 7 shows still another configuration of the measuring head 20 in the beam adjusting device 10 of the first embodiment. Since the configuration other than the measuring head 20 is the same as that of the first embodiment, detailed description thereof is omitted.
[0135]
As shown in FIG. 7, in the measuring head 20 of the fourth embodiment, the light transmitting means and the light deflecting means are constituted by L-shaped optical fibers 33. Thus, by providing the L-shaped optical fiber 33 at the beam imaging position (R on the photoconductor surface), the functions of the light transmitting means and the light deflecting means of the first embodiment can be used together. Therefore, the number of parts can be reduced.
[0136]
By using an L-shaped optical fiber as the light transmitting means provided at the beam imaging position of the light scanning and the light deflecting means for deflecting the beam image in the main scanning direction, the beam image on the photoreceptor surface is mainly used. It can be obtained by being deflected in the scanning direction.
[0137]
The function of the light transmitting means and the function of the light deflecting means can be used together by the L-shaped optical fiber provided at the beam imaging position, so that the number of parts can be reduced.
[0138]
The beam adjusting device described above can be used for an image forming apparatus such as a laser beam printer and a laser facsimile, and measures a writing position and a light amount of a laser beam of a scanning optical unit in the image forming apparatus, and creates and reflects correction data. By doing so, the writing position and light amount can be adjusted, and the present invention can be applied to a beam correction data creation method, a color image forming apparatus, a program, a storage medium, and a printed matter.
The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the gist of the present invention.
[0139]
【The invention's effect】
As described above, according to the present invention, the beam for the image forming apparatus is provided in the space occupied by the photoreceptor unit in the image forming apparatus via the image forming apparatus side mounting means. Since the adjustment device can be attached and detached, it is not necessary to remodel a special image forming apparatus. Further, by mounting this beam adjusting device in the image forming apparatus, it is possible to measure the dot position and the light beam amount formed by the laser beam with high accuracy in an actual use state. In addition, since the beam position and the beam light amount of the finished product can be adjusted, the measurement can be performed by an operator using a simple operation in an adjustment process at a factory.
[0140]
According to the second aspect of the present invention, since the beam adjusting device for the image forming apparatus can be attached and detached by the same space and the same detaching operation as the photosensitive member, it is not necessary to remodel the special image forming apparatus. By mounting the beam adjustment device for the image forming apparatus in the image forming apparatus, it is possible to measure the dot position formed by the laser beam with high accuracy in an actual use state. In addition, since the beam position of the finished product can be adjusted, the measurement can be performed by an operator using a simple operation in the adjustment process at the factory.
[0141]
According to the third aspect of the present invention, since the image forming apparatus is set in the adjustment mode, the emission control of the laser beam can be performed in the operating state by communication between the control means of the adjustment apparatus and the control means of the image forming apparatus. It is not necessary to provide a special circuit in the adjusting device, and the cost and space can be saved.
[0142]
According to the invention described in claim 4, for example, a two-dimensional area sensor is provided as an imaging unit at an image forming position of the beam, and a measurement head including the imaging unit is moved in the optical scanning direction. Measurement can be performed over the entire effective writing width.
[0143]
Further, according to the invention described in claim 5, since the beam image at the image forming position of the beam can be enlarged and transmitted by the light transmitting means, the measurement accuracy of the position of the scanning beam and the light amount can be improved. Further, by moving the measuring head including the light transmitting means and the imaging means in the optical scanning direction, it is possible to perform the measurement over the entire effective writing width.
[0144]
Further, according to the invention described in claim 6, since the protrusion of the measuring head can be reduced, the cross-sectional area of the side surface of the adjusting device can be reduced, and the beam adjusting device can be made smaller than the photoconductor unit. It can be directly inserted into the image forming apparatus to measure and adjust the beam image. In addition, the measuring head including the light transmitting unit, the light deflecting unit, the magnifying optical unit, and the imaging unit, once adjusted, does not change their respective positional relationships, and is moved in the main scanning direction in a fixed state, Measurement can be performed over the entire effective writing width.
[0145]
Further, according to the invention described in claim 7, the beam image is captured and transmitted by the optical fiber provided at the image forming position of the beam, with the arrangement direction being arranged substantially in the normal direction of the photoconductor surface. Since the beam image is transmitted with high efficiency and low distortion, the beam position can be reliably measured by the imaging means.
[0146]
According to the invention described in claim 8, the functions of the light transmitting means and the light deflecting means can be combined and used by the L-shaped optical fiber provided at the beam imaging position. Points can be reduced.
[0147]
According to the ninth aspect of the present invention, in the color image forming apparatus using the same four beam adjusting devices, the light scanning beam is simply rotated in advance so as to be in the beam incident direction. Adjustments can be made at once.
[0148]
According to the tenth aspect, the beam position can be measured by the beam position calculation unit from the beam image captured by the imaging unit.
[0149]
According to the eleventh aspect, the absolute position of the dot in the optical scanning direction can be measured by calculating the beam position measured by the imaging unit and the position of the measuring head in the main scanning direction. it can.
[0150]
According to the twelfth aspect of the present invention, it is possible to measure a light beam distribution from a beam image picked up by an image pickup means.
[0151]
Further, according to the invention of claim 13, since it is not necessary to calculate dot position shift correction data by performing calculations in the image forming apparatus, no load is imposed on the image forming apparatus, so that the cost is not increased.
[0152]
Further, according to the invention described in claim 14, since it is not necessary to calculate the light amount correction data by performing calculations in the image forming apparatus, no load is imposed on the image forming apparatus, which does not lead to an increase in cost.
[0153]
Further, according to the invention described in claim 15, since it is not necessary to calculate the dot misalignment correction data and the beam light amount correction data by performing calculations in the image forming apparatus, no load is applied to the image forming apparatus. In addition, since the calculation is performed by an external general-purpose calculation device with storage means, no load is applied to the beam adjustment device. Also, the cost does not increase.
[0154]
According to the invention described in claim 16, it is possible to reliably capture the scanning beam without depending on the timing of the horizontal synchronizing signal of the imaging unit when imaging is performed by the imaging unit using a signal from an external trigger. Can be.
[0155]
According to the seventeenth aspect of the present invention, the dot misalignment correction data and the beam light amount correction data can be transferred to the LD light emission pattern generation unit of the image forming apparatus and stored therein, and can be corrected by the LD. Since the beam can be emitted with the amount of emitted light and at the corrected timing, the dots formed by the scanning beam on the photoreceptor surface can have the appropriate amount of light at the appropriate positions.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a beam adjustment device of a first embodiment as one embodiment according to the present invention.
FIG. 2 is a schematic system configuration diagram of a beam adjusting device of a first embodiment as one embodiment according to the present invention.
FIG. 3 is a schematic configuration diagram showing a beam adjusting device according to a second embodiment of the present invention.
FIG. 4 is a schematic configuration diagram showing a beam adjusting device according to a third embodiment of the present invention.
FIG. 5 is a front view showing a schematic configuration of a beam adjusting device of a first embodiment as one embodiment according to the present invention.
FIG. 6 is a schematic side sectional view of the beam adjusting device of FIG. 5;
FIG. 7 is a diagram showing a configuration example of a measuring head provided in a beam adjusting device according to a fourth embodiment of the present invention.
FIG. 8 is a timing chart showing the detection timing of a beam image in the beam adjusting device of the first embodiment as one embodiment according to the present invention.
FIG. 9 is a measurement flowchart in the beam adjustment device of the first embodiment as one embodiment according to the present invention.
FIG. 10 is a light emission timing chart in an LD light emission pattern generation unit in the beam adjustment device of the first embodiment as one embodiment according to the present invention.
FIG. 11 is a diagram showing a measurement example of a magnification error and a scanning line bending amount in the beam adjusting device according to the first embodiment as one embodiment according to the present invention;
FIG. 12 is a diagram showing a general color image forming apparatus using the beam adjusting device of the present invention.
FIG. 13 is a diagram illustrating attachment / detachment of a photoconductor unit used in the image forming apparatus of FIG. 12;
FIG. 14 is a diagram illustrating a state in which a beam image captured by a two-dimensional area sensor is image-processed in the beam adjustment device according to the first embodiment as one embodiment according to the present invention.
FIG. 15 is an explanatory diagram of a step of obtaining a position correction amount from a difference between a dot measurement position and an ideal position in the beam adjustment device according to the first embodiment as one embodiment of the present invention.
FIG. 16 is a block diagram illustrating an example of a circuit configuration of a pulse width modulation device and the like included in each scanning optical unit of the image forming apparatus to which the beam adjustment device according to the first embodiment as one embodiment according to the invention is applied. It is.
FIG. 17 is a timing chart illustrating the operation of the pulse width modulation device of FIG.
FIG. 18 is a conceptual diagram of a scanning optical unit provided in the image forming apparatus of FIG.
[Explanation of symbols]
10. Beam adjustment device (beam adjustment means)
11 Scanning optical unit (optical writing optical system)
12 Laser light source (laser diode)
13 Sync detection PD (photodiode)
14 Polygon mirror
15 fθ lens
16 Sync signal
17 LD light emission pattern generator
18 Detection trigger generation means
20 measuring head 20 (beam measuring means)
21 Two-dimensional area sensor (imaging means)
22 Light transmission means
23 Light deflection means
24 Magnification detection means (magnification optical means)
25 Moving stage (moving means)
26 Position detection head
27 Position detection scale
28 Moving Stage Guide
29 Moving stage motor
30 side plate
31a, 31b mounting means
32 rotating means
33 L-shaped optical fiber
40 adjustment control unit (adjustment control means)
41 Image processing unit
42 Beam position calculator
43 Beam Light Amount Calculator (Beam Light Amount Calculator)
44 stage position detecting section (stage position detecting means)
45 data storage unit (storage means for storing beam intensity data)
46 communication unit (communication means)
47 Mechanism control unit
48 Position correction data calculation unit (Position correction data calculation means)
49 Light quantity compensation data calculation unit (light quantity compensation data calculation means)
50 External computing device
51 Data output unit (output means)
52 data input unit (input means)
53 Data transfer unit (transfer means)
54 Display
60 Image forming apparatus
71 Pulse width modulation section
72, 72M, 72C, 72Y, 72K Photoconductor unit
80 PLL circuit
81 VCO
82 divider circuit
83 Phase comparator or phase frequency comparator
84 selector
85 Analog delay section
86 pulse width generator
87 control unit
88 Table data
S Spades

Claims (18)

An image having a photoreceptor unit which is detachable at an optical scanning writing position of an optical writing beam, and wherein the attaching means for detachably attaching the photoreceptor unit comprises an image forming apparatus side attaching means and a photoreceptor unit side attaching means. A beam adjusting device that adjusts the optical writing beam using the forming device,
Attachment means engageable with the image forming apparatus-side attachment means is provided integrally with the beam adjusting means, and the beam adjusting means is provided in a space occupied by the photoreceptor unit removed from the image forming apparatus. The image forming apparatus is detachably attached to the image forming apparatus-side attaching means via the engageable attaching means, and further, when the beam adjusting means is attached to the space via the attaching means, A beam adjustment device for an image forming apparatus, wherein a measurement position is arranged at a position corresponding to a photoconductor surface of a body unit. 2. The beam adjusting device for an image forming apparatus according to claim 1, wherein the engaging means provided on the beam adjusting means has the same structure as the attaching means on the photoconductor unit side. The beam adjustment unit includes a beam measurement unit configured to measure an imaging state of a beam formed by optical scanning on a photoconductor surface of the photoconductor unit; a communication unit configured to communicate with a control unit of the image forming apparatus; 3. The beam adjustment device for an image forming apparatus according to claim 1, further comprising an adjustment control unit for controlling the communication unit and the communication unit. The beam measuring unit includes an imaging unit disposed at an image forming position of a beam by optical scanning on the photoconductor surface, and a moving unit that moves the imaging unit in the optical scanning direction. The beam adjusting device for an image forming apparatus according to claim 3. The beam measuring unit includes: a light transmitting unit that enlarges and transmits a beam image at a beam imaging position by light scanning on the photoconductor surface; an imaging unit that captures an emission surface of the light transmitting unit; 4. The beam adjusting device for an image forming apparatus according to claim 3, further comprising a moving unit that moves the unit and the imaging unit in the optical scanning direction. The beam measuring means is disposed at an image forming position of a beam by light scanning on the photoconductor surface, a light transmitting means for transmitting a beam image, a light deflecting means for deflecting the beam image in a light scanning direction, Magnifying optical means for magnifying a beam image to form an image on an image forming surface; imaging means provided on the image forming surface; the light transmitting means; the light deflecting means; the magnifying optical means; 4. A beam adjusting device for an image forming apparatus according to claim 3, further comprising a moving unit for moving a unit in the light scanning direction. The image according to claim 5, wherein the light transmitting unit includes an optical fiber bundle, and an arrangement direction of the optical fibers of the optical fiber bundle is arranged in a substantially normal direction of the photoconductor. Beam adjustment device for forming equipment. 7. The beam adjusting device according to claim 6, wherein the light transmitting unit and the light deflecting unit are configured by one L-shaped optical fiber. The beam measurement unit has a rotation center that is the same as the rotation center of the photoconductor, and includes a rotation unit for rotating a measurement position in a direction of incidence of a beam by optical scanning of the image forming apparatus. The beam adjusting device for an image forming apparatus according to claim 3, wherein: 5. The beam adjusting device according to claim 4, wherein the beam measuring unit includes a beam position calculating unit that calculates a beam position in an imaging screen captured by the imaging unit. 7. The beam adjusting device for an image forming apparatus according to claim 4, wherein said beam measuring means includes a stage position detecting means for detecting a moving amount of said moving means. 5. The beam adjusting device for an image forming apparatus according to claim 4, wherein the beam measuring unit includes a beam light amount calculating unit that calculates a light amount of a beam in an image captured by the image capturing unit. The adjustment control unit includes a storage unit that stores the beam position data and the stage position data acquired while being moved by the moving unit, and position correction data that calculates position deviation correction data of dots formed by the optical writing beam. 5. The beam adjusting device for an image forming apparatus according to claim 4, further comprising a calculating unit. 4. The apparatus according to claim 3, wherein the adjustment control unit includes a storage unit that stores the beam light amount data acquired while being moved by the moving unit, and a light amount correction data calculation unit that calculates the beam light amount correction data. 3. The beam adjusting device for an image forming apparatus according to claim 1. The adjustment control unit includes an output unit configured to output beam position data, stage position data, and beam light amount data acquired while being moved by the movement unit, and a position shift correction of a dot formed by the optical writing beam. 4. The beam adjusting device for an image forming apparatus according to claim 3, further comprising input means for acquiring data and beam light amount correction data of the optical writing beam from outside. The adjustment control unit communicates with the control unit of the image forming apparatus, and detects a trigger timing of the imaging unit based on an output signal from a synchronization detection unit that detects a scanning timing of a scanning beam. The beam adjustment device for an image forming apparatus according to claim 4, further comprising: The adjustment control unit is configured to transfer at least one of positional deviation correction data of dots formed by the optical writing beam and beam light amount correction data of the optical writing beam to an LD emission pattern generation unit of the image forming apparatus. 4. The beam adjusting device for an image forming apparatus according to claim 3, further comprising a transfer unit. An image having a photoreceptor unit which is detachable at an optical scanning writing position of an optical writing beam, and wherein the attaching means for detachably attaching the photoreceptor unit comprises an image forming apparatus side attaching means and a photoreceptor unit side attaching means. A beam adjusting method for adjusting the optical writing beam using the forming apparatus,
A beam adjusting unit integrally provided with an attaching means engageable with the image forming apparatus side attaching means is provided in the space occupied by the photoreceptor unit removed from the image forming apparatus. When the beam adjustment unit is mounted in the space via the mounting unit, the mounting unit is detachably attached to the image forming apparatus side mounting unit via a possible mounting unit. A beam adjustment method for an image forming apparatus, wherein a beam is adjusted by arranging a measurement position at a position to be adjusted.

Images