JP2004320538A

JP2004320538A - Image reading apparatus and image forming apparatus

Info

Publication number: JP2004320538A
Application number: JP2003113054A
Authority: JP
Inventors: Kunihisa Yamaguchi; 邦久山口
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2003-04-17
Filing date: 2003-04-17
Publication date: 2004-11-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus which improves copying quality and does not employ a special device configuration in a change of a copying machine and scanner etc as a means for the purpose, and gets a result same as regular sheet manuscript copying with no floating. <P>SOLUTION: The image reading apparatus comprises a scanner unit A traveling along the bottom surface of a manuscript holder 1. The apparatus reads the image of a manuscript 10 set on the manuscript holder 1. Moreover, the apparatus comprises a range-finding sensor 7 integrally attached to the scanner unit A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、原稿台から浮き上がった原稿の作像を行うスキャナ駆動機構、スキャナデータ取り込み光学系、機構系等を備えた画像読み取り装置、及びこれを備えた画像形成装置に関するものである。
【０００２】
【従来の技術】
従来から書籍等の厚手の原稿のコピーを撮るための画像読み取り装置は知られている（例えば、特許文献１および２参照）。
【特許文献１】特開２０００−１６５６０８公報
【特許文献２】特開２０００−１６５６１７公報
【０００３】
【発明が解決しようとする課題】
特許文献１および２によれば、画像読み取り装置はブック専用機のような形状になり、通常のシート物のコピーには使用し難い形状となっている。また見開きのブック物の複写機想定では読み込み系ユニットが２つも必要となってくるため機械のコスト面でも不向きである。
図６は一般的なスキャナの結像系部分を示す概略図である。図６には、原稿台２１の他に、画像取り込みユニット２２を構成する結像レンズ系２３、ＣＣＤ２４、ランプ２５およびミラー２６が略示されている。
複写機、スキャナ機において、ブック等厚手の原稿のコピーを撮ると、ブックの綴じこみ部が原稿台より浮き上がる現象が生じ、その結果としてコピーの文字歪み、文字ボケ、およびその結果としての原稿の解像不足、また照射光の反射の低下、外部光の入射等による、コピーの黒筋発生等、著しくコピー品質を下げる結果が生じる。
映像の歪みを取り除くことが主眼の技術提案は多いが、原稿歪み、浮き上がりによる原稿ピントのずれをも解消しようとする提案は少ない。
そこで本発明の目的は、上記の問題点を解決するために、コピー品質の劣化を改善し、またそのための手段である複写機およびスキャナ機等の変更が、特殊な機器の形態にならず、さらに通常の浮きのないシート原稿コピーと同等の結果を得る画像読み取り装置を提供することにある。
【０００４】
【課題を解決するための手段】
前記の課題を解決するために、請求項１記載の発明では、原稿台の下面に沿って移動するスキャナ部を有し、前記原稿台上にセットした原稿の画像を読み取る画像読み取り装置において、前記スキャナ部に一体的に取り付けられた測距センサを有する画像読み取り装置を最も主要な特徴とする。
請求項２記載の発明では、前記測距センサは１原稿のスキャン方向、全範囲の距離を測定し、原稿面の前記原稿台からの浮き量を測定する請求項１記載の画像読み取り装置を主要な特徴とする。
請求項３記載の発明では、前記スキャナ部は原稿像を第１ミラーによる反射および集光レンズを介したあと、ＣＣＤセンサ上に結像するよう配置されており、前記原稿像の映像を最初に反射する前記第１ミラーは反射角が変化でき得る構造を有する請求項１記載の画像読み取り装置を主要な特徴とする。
請求項４記載の発明では、前記第１ミラーは、集光レンズ、およびＣＣＤに対し、光軸方向に進退可能である構造を有する請求項３記載の画像読み取り装置を主要な特徴とする。
請求項５記載の発明では、前記第１ミラーの反射角は、常時は基準となる一定の角度を保持し、それに対し変化でき得る角度は増減、両方向に可能である請求項４記載の画像読み取り装置を主要な特徴とする。
請求項６記載の発明では、前記画像読み取り装置のスキャン動作によるＣＣＤおよびレンズ部の作動量と原稿浮き量とにより、原稿面の傾きを計算し、それに対応する角度に、前記第１ミラーの反射角を変化させる請求項２記載の画像読み取り装置を主要な特徴とする。
請求項７記載の発明では、前記スキャナ部の作動量と、それに伴う前記測距離センサにより測定された原稿浮き量から前記原稿面のスキャン方向の原稿長さを計算し、それにあった長さにスキャンデータを置き換えることにより、前記原稿面の浮きによるデータのスキャン方向の圧縮を補正する請求項２記載の画像読み取り装置を主要な特徴とする。
【０００５】
請求項８記載の発明では、原稿面の傾きによる前記ミラー反射面の傾き角の変化、および原稿の浮きによる焦点面の光軸方向長さ変化に対し、前記ＣＣＤから前記原稿面までの距離が変化しないように、前記ＣＣＤと第１反射面の距離を変化させる請求項３記載の画像読み取り装置を主要な特徴とする。
請求項９記載の発明では、前記光軸方向長さ変化の補正を前記第１ミラーに続く、それ以降の反射ミラーによって行う請求項８記載の画像読み取り装置を主要な特徴とする。
請求項１０記載の発明では、前記補正によりスキャナ取り込み位置と、取り込みデータの間の関係はずれるが、仮想平面を想定したデータの位置補正を行うことによって、また隣り合うデータの重み補完を行うことにより補正データを作成し、ずれ補正を行う請求項７または８のいずれか１項記載の画像読み取り装置を主要な特徴とする。
請求項１１記載の発明では、前記測距センサはスキャン方向と直角方向に複数個設け、前記原稿のスキャン方向に対し直角な方向の原稿浮き量の変化も測定する請求項１記載の画像読み取り装置を主要な特徴とする。
請求項１２記載の発明では、複数のセンサの測定浮き量の差が大きく、撮影レンズ系の許容深度内に収まらないときには、収まらない部分の映像を部分取り直し後、合成することにより映像データを作成する請求項８記載の画像読み取り装置を主要な特徴とする。
請求項１３記載の発明では、複写機、スキャナ機には、前記補正動作を行うかどうか選択できるような構成を有し、前記補正動作を始めるときも、原稿面の傾きを計算し、それに対応する角度に前記第１ミラーの反射角を変化させる作動は、原稿全範囲の浮き量の測定を終え、浮き範囲を特定した後、開始する請求項１１記載の画像読み取り装置を主要な特徴とする。
請求項１４記載の発明では、請求項１乃至１１の何れか一項に記載の画像読み取り装置と、画像形成部と、給紙部と、を少なくとも備えたことを特徴とする。
【０００６】
【発明の実施の形態】
以下、図面により本発明の実施の形態を詳細に説明する。図１は本発明による画像読み取り装置の画像取り込み結像部（スキャナ部）を示す概略図である。本発明の目的を達成するためには、（１）原稿に浮きがあって、コピーがボケる問題に関し、原稿がどれだけの量浮き上がっているかを測定する手段が必要であり、その後、測定により得た浮き量に光学系のピントをあわせ、正確な映像情報を得ることが必要となる。
また、（２）原稿の浮き上がりにより、文字が歪む問題に関し、原稿のゆがみ形状を測定し、浮き上がりを解消して原稿が平面状に展開されたと想定した原稿補正を行う必要があり、このために読み取りヘッドのスキャン量（読み込み方向の単位作動量）に合わせた浮き量を測定し原稿の歪み形状を把握する。
さらに、（３）原稿の浮き上がりにより、解像が粗くなること、読めなくなる（映像読み込み方向に対し原稿面の変移角が急なときに生じる）問題に関し、また原稿面の傾きにより、反射光が少なくなりコピーに黒スジが発生する問題に関し、反射ミラーを可動式にし、原稿に正対した角度に出来るだけ近い角度で原稿の情報を読むようにする必要がある。
【０００７】
まず図１により構成を説明する。画像取り込み結像部（スキャナ部）Ａにおいて透明な原稿台１の面の下側には画像取り込みユニット２があり、図１の左から右にスキャンニングを行う。この画像取り込みユニット２内には、画像の映像をＣＣＤ６に導く第１ミラー３、ミラーユニット４が配置され、さらに結像レンズ系５、像を生成するＣＣＤ６を有している。その他ユニット内に測距センサ７を有している。
ここで第１ミラー３は映像光線の反射線を軸として、ミラーモータ８等の作動により反射面の角度を変化させ得る構造を備えている。またミラーユニット４は通常は画像取り込みユニット２に対し静止しているが、モータ等の作動により相対的にスキャンニング方向に可動できる構造（図示していない）を備えている。
図１により作動を説明する。まず原稿台１に原稿が載せられているとき、画像取り込みユニット２は、それに一体的に取り付けられた測距センサ７とともに紙面左から右に作動し、原稿面の映像をＣＣＤ６に取り込んでスキャンニングを行う。
原稿台１の映像は図内のランプ９により照明され、矢印の如く映像光線は第１ミラー３〜ミラーユニット４で反射された後、結像レンズ系５で集光されＣＣＤ６上に像を作ることとなる。
またこれと同時に測距センサ７は、図のａ寸法先の原稿面までの距離変化を測定しており、原稿面の浮きを検出する。これにより、画像取り込みユニット２のスキャン方向へのステップごとの動きに対する、前記浮き量の変化により、原稿面の面形状の変化、傾きを計算するとともに、原稿面を水平に展開したときの長さも計算する。
前記原稿面の傾き結果より、測定した点での画像取り込み時には、原稿面に対し光軸が出来るだけ直角になるようにミラー３の傾き角を設定するとともに、これにより変化する原稿面からＣＣＤ面までの距離を一定に保つために（焦点を合わせるため）、ミラーユニット４の位置を画像取り込みユニット２に対し変化させて焦点を合わせ、画像データを取り込むこととなる。ここでミラーユニット４を作動させる代わりに、結像レンズ系５を作動させて焦点合わせを行うことも可能である。
図２は測距センサおよび測距光線を示す概略図である。図２には原稿１０、投光光源１１、ＣＣＤ位置センサ１２、原稿１０が原稿台１面に密着しているときの測距光線の経路ｂ、原稿１０が原稿台１面からはなれて浮いているときの測距光線の経路ｃを示している。
【０００８】
図３は測距データからの原稿面傾き、原稿展開長さの求め方を説明する概略図である。ここで測距センサ７の測定値より原稿面の面形状の変化、傾き、原稿面を水平に展開した長さの計算方法を図３において説明する。
図３において、センサヘッドの測定ポイントのＸ座標を

とし、それに対応する原稿面の浮き量を

とすると

の大きさはセンサの受光位置の変化に対応して求めることができ、面の傾きは

であり、その法線方向は

となる。
また原稿展開長さは

となる。
【０００９】
図４は原稿の面の法線方向が変化したときにおける第１ミラー３面の傾き角度の修正量を示す概略図である。図６では原稿１０の面の法線方向が鉛直方向に対してαなる角度に変化したときに、第１ミラー３面の水平方向とのなす角を、π／４＋α／２と修正すれば、第１ミラー３面での反射光線はミラーユニット４に至ることとなる。
上記方法により面の変化した原稿１０を補正した形で取り込み、平面展開した原稿データとすることにより、ブック物等における映像情報の取り込み画像改善を行う。
複写機、スキャナ機（とくにブック物等厚手で綴じられた原稿のコピー、スキャン）また立体物の急激な形状変化面の立体形状把握のための３Ｄ映像取り込み装置に応用し得る。
測距センサ７により原稿１０の浮きの有無、浮きの高さが検知できることにより、自動により、浮きのある原稿１０であるかどうかを判定できることとなり、自動補正も可能にする条件である。
浮いた原稿１０、傾いた原稿１０に対しできるだけ、原稿１０に直行した方向から情報を取得し得るようになり、文字の歪み、圧縮が少なく解像度の高い情報、画像をＣＣＤに入力できることになる。
浮いた原稿１０の面のためピントがボケる現象に対し補正が可能となり、ピントの合った画像を得ることができる。
第１ミラー３の反射角が常時は基準となる一定の角度を保持し、それに対し変化でき得る角度が増加または減少の両方向に可能であることはブックの両ページにわたる原稿１０面の面変化等傾きが基準角度に対し正負の関係変化で変わる面に対して必要な項目である。
原稿１０に浮きがない場合、第１ミラー３は４５度の角度で固定されている。これに対し原稿１０がスキャン進行方向に対し浮き始める場合は、ミラー角度は４５度より起こした角度に設定し、原稿１０面の垂直方向の情報を得やすくする。また一方スキャン進行方向に対し、原稿１０の浮き量が減少する場合はその逆のミラー角度の設定となる。
【００１０】
浮き量の測定から面の傾き方向を知ることおよび浮き量の測定から原稿１０の水平展開寸法を知ることができ、データのスキャン方向長さの補正が行え、正確な平面展開原稿に補正することができる。
画像面浮きの焦点合わせを撮影レンズ系の焦点距離変化で行うことも可能であるが、この場合ＣＣＤと撮影レンズ（焦点調整レンズ）の距離を変化させるため、像倍率等の変化が生じる。このため、その後映像の倍率補正を行わなければならないこととなる。
この欠点を避けるため、ミラーの作動による補正を行う。この方法によれば画像の浮きによる画像と撮影レンズとの距離変化がミラーを動かすことにより、光路長としては一定に保つこととなり、倍率等は変化が生じない。
浮き上がり原稿の像をミラーの傾き角度を変え、取り込み位置を変化させて取り込んだ場合、取り込み情報の位置は、原稿が平面である場合の規則的な位置に比べてずれたものとなる。
これは原稿が平面の場合、スキャンピッチを規則的に行えば取り込み情報は規則的なピッチの像となるが、ミラー、取り込み位置を変化させた場合は必ずしも規則的なピッチの像とはならない。
これはミラー駆動および光学系のスキャンを行う駆動源が一般的にステップモーターでありアナログ的にコントロールができないことによる。このため前後のスキャン情報を照らし合わせ、中間的な情報を作り、位置情報を作成する必要が生じることを意味している。
測距センサをスキャン方向と直角に複数個設けその距離を平均化すること等により、スキャン方向と直角方向のデーターの取り込みにより良いミラー角度、取り込み位置を設定できることになる。また直角方向に対しても大きなうねりがあるような場合、直角方向のデータもいくつかの範囲に分けて取り込むことにより、良い情報を得ることができる。
以上画像取り込み動作は、通常のコピー動作に比べ時間を要することになる。そのためコピーの品質にあまりこだわらず、早くコピーが必要な場合、不作動とすることでき、また先立って画像の浮きを検知することにより、原稿に浮きがない場合通常のコピー動作に早く入れるようにする。
【００１１】
なお、上記実施形態では何れも画像読み取り装置単体としての構成例を説明したが、本発明の画像読み取り装置は、複写機、プリンタ、ファクシミリ装置などの電子写真式の画像形成装置の読み取り装置としても適用することができる。即ち、図５は本発明の画像取込み結像部Ａを備えた画像形成装置の概略構成図であり、この画像形成装置は、装置本体３０上面の原稿台１上に原稿給紙装置４０を配置した構成を備え、装置本体３０内には、画像取込み結像部Ａ、画像形成部Ｂ、給紙部Ｃ、書込み光学系Ｄ，及び図示しない電装部等が配置されている。画像形成部Ｂは、感光体３１と、その周囲に配置された帯電部３２，露光部３３，現像部３４，転写部３５，及び定着部３６を備えている。
画像取込み結像部Ａにより読取られた原稿台１上の原稿の画像データは、書込み光学系Ｄによってレーザビームとして感光体３１上に照射されて静電潜像が形成される。この静電潜像は現像部３４によって可視像化され、このトナー像を給紙部Ｃから給紙された転写紙上に転写、定着してから機外に排出される。
このような構成を備えた画像形成装置に対して本願発明の画像取込み結像部Ａを適用することにより、上記各実施形態において示した優れた読み取り効果による画質の向上を図ることができる。
【００１２】
【発明の効果】
以上説明したように、請求項１によれば、測距センサーにより原稿の浮きの有無、浮きの高さが検知でき、これにより、画像補正も可能になる。
請求項２によれば、浮いた原稿、（傾いた原稿）に対し出来るだけ直行した方向から情報を取り込むことができ、文字の歪み、圧縮を補正した画像を入力できる。
請求項３によれば、浮いた原稿、傾いた原稿に対しできるだけ、原稿に直行した方向から情報を取得し得るようになり、文字の歪み、圧縮が少なく解像度の高い情報、画像をＣＣＤに入力できることになる。
請求項４によれば、浮いた原稿面の為ピントがボケる現象に対し補正ができ、ピントの合った画像を得ることができる。
請求項５によれば、これはブックの両ページにわたる原稿面の面変化等、傾きが基準角度に対し正負の関係変化で変わる面に対して必要な項目である。
請求項６によれば、浮き量の測定から面の傾き方向を知ることができ、データのスキャン方向の長さの補正が行え正確な平面展開原稿を作成できる。
請求項７によれば、浮き量の測定から原稿の水平展開寸法を知ることができ、データのスキャン方向の長さの補正が行え正確な平面展開原稿を作成できる。
請求項８によれば、焦点合わせを撮影レンズ系の変化を使わず行うことができ、これによって画像倍率補正を省略できる。
【００１３】
請求項９によれば、浮いた原稿面の為ピントがボケる現象に対し補正ができ、ピントの合った画像をえることができる。
請求項１０によれば、ミラーの傾き角度及び取り込み部の作動量はステップ的な動きであるため、原稿のスキャン情報が必ずしも、平面状態で得たとする情報と一致しないので、前後のスキャン情報と照らし合わせ、中間的な情報を作ることができる。
請求項１１によれば、測距センサをスキャン方向と直角に複数個設けその距離を平均化することにより、スキャン方向と直角方向のデータの取り込みにより良いミラー角度、取り込み位置を設定できることになる。
請求項１２によれば、直角方向に対しても大きなうねりがあるような場合、直角方向のデータもいくつかの範囲に分けて取り込むことにより、良い情報を得ることができる。
請求項１３によれば、原稿（ブック等）がスキャン方向と直角方向に対してもうねり（浮き量の違い）があり、同一焦点深度内に収まらない場合には複数回の取り込み動作を、深度が収まらない範囲においておこない、より良い情報を得ることができる。
請求項１４によれば、上記各請求項に基づく作用効果を発揮する画像形成装置を提供することができる。
【図面の簡単な説明】
【図１】本発明による画像読み取り装置の画像取り込み結像部を示す概略図。
【図２】測距センサおよび測距光線を示す概略図。
【図３】測距データからの原稿面傾き、原稿展開長さの求め方を説明する概略図。
【図４】原稿の面の法線方向が変化したときにおける第１ミラー面の傾き角度の修正量を示す概略図。
【図５】本発明の一実施形態に係る画像形成装置の構成説明図。
【図６】一般的なスキャナの結像系部分を示す概略図。
【符号の説明】
１原稿台、２画像取り込みユニット、３第１ミラー、４ミラーユニット、５結像レンズ系、６ＣＣＤ、７測距センサ、１０原稿、１１投光光源、１２ＣＣＤ位置センサ、Ａスキャナ部、ｂ原稿１０が原稿台１面からはなれて浮いているときの測距光線の経路、ｃ原稿が原稿台面に密着しているときの測距光線の経路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a scanner driving mechanism for forming an image of a document floating from a document table, an image reading apparatus including a scanner data capturing optical system, a mechanism system, and the like, and an image forming apparatus including the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image reading apparatus for taking a copy of a thick original such as a book is known (for example, see Patent Documents 1 and 2).
[Patent Document 1] JP-A-2000-165608 [Patent Document 2] JP-A-2000-165617
[Problems to be solved by the invention]
According to Patent Literatures 1 and 2, the image reading device has a shape like a dedicated book machine, and has a shape that is difficult to use for copying a normal sheet material. Further, in the case of a two-page spread copy machine, two reading units are required, which is not suitable in terms of machine cost.
FIG. 6 is a schematic diagram showing an image forming system portion of a general scanner. FIG. 6 schematically shows an image forming lens system 23, a CCD 24, a lamp 25, and a mirror 26, which constitute the image capturing unit 22, in addition to the document table 21.
When taking a copy of a thick original such as a book in a copier or a scanner, a phenomenon occurs in which the binding portion of the book rises above the platen, and as a result, the character distortion of the copy, the character blur, and the resultant original Insufficient resolution, reduced reflection of irradiation light, incidence of external light, and the like, result in a significant reduction in copy quality, such as black streaks in the copy.
Although there are many technical proposals whose main purpose is to remove image distortion, there are few proposals for eliminating original document shift due to original distortion and floating.
Therefore, an object of the present invention is to solve the above problems, to improve the deterioration of copy quality, and to change the copying machine, scanner, and the like as means for that purpose, do not take the form of special equipment, It is still another object of the present invention to provide an image reading apparatus that can obtain the same result as a normal sheet document copy without floating.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 has an image reading device that has a scanner unit that moves along the lower surface of a document table and reads an image of a document set on the document table. The most main feature is an image reading device having a distance measuring sensor integrally attached to the scanner unit.
According to the second aspect of the present invention, the distance measuring sensor measures the distance in the scanning direction and the entire range of one document, and measures the amount of floating of the document surface from the document table. Characteristics.
According to the third aspect of the present invention, the scanner unit is arranged to form an image of the original image on a CCD sensor after reflecting the original image through a first mirror and a condensing lens. The main feature of the image reading apparatus according to claim 1, wherein the reflecting first mirror has a structure capable of changing a reflection angle.
According to a fourth aspect of the present invention, the image reading apparatus according to the third aspect is characterized in that the first mirror has a structure capable of moving back and forth in the optical axis direction with respect to the condenser lens and the CCD.
According to the fifth aspect of the present invention, the reflection angle of the first mirror always keeps a constant reference angle, and the angle which can be changed can be increased or decreased in both directions. The device is the main feature.
According to the sixth aspect of the present invention, the inclination of the document surface is calculated based on the operation amounts of the CCD and the lens unit by the scanning operation of the image reading device and the document floating amount, and the reflection of the first mirror is adjusted to an angle corresponding thereto. The image reading apparatus according to claim 2 for changing the angle is a main feature.
In the invention according to claim 7, the length of the original in the scanning direction of the original surface is calculated from the amount of operation of the scanner unit and the amount of floating of the original measured by the distance measuring sensor associated therewith. The main feature of the image reading apparatus according to the present invention is that the compression of the data in the scanning direction due to the floating of the document surface is corrected by replacing the scan data.
[0005]
In the invention described in claim 8, the distance from the CCD to the document surface is changed with respect to a change in the tilt angle of the mirror reflecting surface due to the tilt of the document surface and a change in the length of the focal plane in the optical axis direction due to the floating of the document. The main feature of the image reading apparatus according to claim 3 is that the distance between the CCD and the first reflection surface is changed so as not to change.
According to a ninth aspect of the present invention, the main feature of the image reading apparatus according to the eighth aspect is that the correction of the change in the length in the optical axis direction is performed by a reflection mirror subsequent to the first mirror.
According to the tenth aspect of the present invention, the relationship between the scanner capture position and the capture data is deviated by the correction. However, by performing position correction of data assuming a virtual plane, and by performing weight complementation of adjacent data. An image reading apparatus according to any one of

claims

7 and 8, wherein correction data is created and deviation correction is performed.
The image reading device according to claim 1, wherein a plurality of the distance measuring sensors are provided in a direction perpendicular to a scanning direction, and a change in a floating amount of the document in a direction perpendicular to the scanning direction of the document is also measured. Is the main feature.
According to the twelfth aspect of the present invention, when the difference between the measured floating amounts of the plurality of sensors is large and does not fall within the permissible depth of the photographing lens system, the image of the part that does not fit is retaken and then combined to create video data. The image reading apparatus according to claim 8 is a main feature.
In the invention according to claim 13, the copier and the scanner have a configuration capable of selecting whether or not to perform the correction operation. When the correction operation is started, the inclination of the document surface is calculated and the correction is performed. The main feature of the image reading apparatus according to claim 11, wherein the operation of changing the reflection angle of the first mirror to the desired angle is started after the measurement of the floating amount of the entire original document is completed, and the floating range is specified. .
According to a fourteenth aspect of the present invention, at least the image reading device according to any one of the first to eleventh aspects, an image forming unit, and a paper feeding unit are provided.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an image capturing / imaging unit (scanner unit) of an image reading apparatus according to the present invention. In order to achieve the object of the present invention, (1) a measure for measuring how much the document is raised is necessary for the problem that the document is raised and the copy is blurred. It is necessary to focus the optical system on the obtained floating amount and obtain accurate video information.
(2) Regarding the problem that characters are distorted due to the lifting of the document, it is necessary to measure the distortion shape of the document and correct the document assuming that the rising is resolved and the document is spread out flat. The floating amount is measured in accordance with the scanning amount of the reading head (unit operation amount in the reading direction) to grasp the distortion shape of the document.
Further, (3) the problem that the resolution becomes coarse due to the lifting of the document and the reading becomes impossible (occurs when the transition angle of the document surface is steep with respect to the image reading direction), and reflected light is generated due to the inclination of the document surface. With regard to the problem of the occurrence of black streaks in the copy, it is necessary to make the reflecting mirror movable so as to read the information of the document at an angle as close as possible to the angle directly facing the document.
[0007]
First, the configuration will be described with reference to FIG. An image capturing unit 2 is provided below the transparent platen 1 in the image capturing and imaging unit (scanner unit) A, and performs scanning from left to right in FIG. In the image capturing unit 2, a first mirror 3 and a mirror unit 4 for guiding an image image to the CCD 6 are arranged, and further, an image forming lens system 5 and a CCD 6 for generating an image are provided. In addition, a distance measuring sensor 7 is provided in the unit.
Here, the first mirror 3 has a structure capable of changing the angle of the reflection surface by operating the mirror motor 8 or the like with the reflection line of the image light beam as an axis. The mirror unit 4 is normally stationary with respect to the image capturing unit 2, but has a structure (not shown) that can be relatively moved in the scanning direction by operation of a motor or the like.
The operation will be described with reference to FIG. First, when a document is placed on the document table 1, the image capturing unit 2 operates from left to right on the paper together with a distance measuring sensor 7 integrally attached thereto, and captures an image of the document surface into the CCD 6 for scanning. I do.
The image of the document table 1 is illuminated by a lamp 9 in the figure, and the image light rays are reflected by the first mirror 3 to the mirror unit 4 as shown by the arrows, and then condensed by the imaging lens system 5 to form an image on the CCD 6. It will be.
At the same time, the distance measurement sensor 7 measures the change in distance to the original surface at the dimension a in the figure, and detects the floating of the original surface. Thus, the change in the floating amount with respect to the stepwise movement of the image capturing unit 2 in the scanning direction is used to calculate the change in the surface shape and the inclination of the document surface, and the length when the document surface is horizontally developed. calculate.
Based on the result of the inclination of the original surface, at the time of capturing an image at the measured point, the inclination angle of the mirror 3 is set so that the optical axis is as perpendicular to the original surface as possible, and this changes the original surface to the CCD surface. In order to maintain a constant distance (for focusing), the position of the mirror unit 4 is changed with respect to the image capturing unit 2 so as to focus and capture image data. Here, instead of operating the mirror unit 4, it is also possible to operate the imaging lens system 5 to perform focusing.
FIG. 2 is a schematic diagram showing a distance measuring sensor and a distance measuring ray. FIG. 2 shows the original 10, the light projecting light source 11, the CCD position sensor 12, the path b of the distance measuring beam when the original 10 is in close contact with the original table 1, and the original 10 floating away from the original table 1. 4 shows the path c of the distance measuring light beam when the distance is present.
[0008]
FIG. 3 is a schematic diagram for explaining how to obtain the document surface inclination and the document development length from the distance measurement data. Here, a method of calculating the change in the surface shape of the document surface, the inclination, and the length of the document surface horizontally developed from the measured values of the distance measuring sensor 7 will be described with reference to FIG.
In FIG. 3, the X coordinate of the measurement point of the sensor head is

And the corresponding floating amount of the document surface

Then

Can be obtained in accordance with the change in the light receiving position of the sensor.

And its normal direction is

It becomes.
Also, the manuscript deployment length is

It becomes.
[0009]
FIG. 4 is a schematic diagram showing a correction amount of the inclination angle of the first mirror 3 when the normal direction of the surface of the document changes. In FIG. 6, when the normal direction of the surface of the document 10 changes to an angle of α with respect to the vertical direction, if the angle between the horizontal surface of the first mirror 3 and π / 4 + α / 2 is corrected, The light reflected by the first mirror 3 reaches the mirror unit 4.
By taking the original 10 whose surface has changed by the above-described method in a corrected form, and making it into original plane-expanded original data, the captured image of video information in a book or the like is improved.
The present invention can be applied to a copying machine, a scanner machine (especially, copying and scanning of originals bound by a thick material such as a book), and a 3D image capturing device for grasping a three-dimensional shape of a rapidly changing surface of a three-dimensional object.
Since the presence / absence of the document 10 and the height of the document 10 can be detected by the distance measuring sensor 7, it can be automatically determined whether or not the document 10 has the document floating, and this is a condition for enabling automatic correction.
As much as possible, information can be obtained from a direction perpendicular to the original 10 with respect to the floating original 10 and the inclined original 10, so that information and images with less distortion and less compression and high resolution can be input to the CCD.
It is possible to correct the phenomenon of out-of-focus due to the surface of the floating document 10, so that an in-focus image can be obtained.
The fact that the reflection angle of the first mirror 3 always keeps a constant reference angle, and the angle that can be changed with respect to the angle can be increased or decreased in both directions is the change in the surface of the document 10 across both pages of the book. This is a necessary item for a surface whose inclination changes with a positive / negative relationship change with respect to the reference angle.
When the document 10 does not float, the first mirror 3 is fixed at an angle of 45 degrees. On the other hand, when the document 10 starts to float in the scanning direction, the mirror angle is set to an angle raised from 45 degrees to make it easier to obtain information in the vertical direction of the document 10 surface. On the other hand, when the floating amount of the document 10 is reduced with respect to the scanning progress direction, the mirror angle is set in the opposite direction.
[0010]
It is possible to know the inclination direction of the surface from the measurement of the floating amount, and to know the horizontal development dimension of the document 10 from the measurement of the floating amount, to correct the length in the scanning direction of the data, and to correct the document to an accurate planar development document. Can be.
It is also possible to adjust the focal point of the imaging lens system by changing the focal length of the imaging lens system. However, in this case, since the distance between the CCD and the imaging lens (focus adjustment lens) is changed, a change in image magnification or the like occurs. Therefore, the magnification of the video must be corrected thereafter.
In order to avoid this disadvantage, correction is performed by operating the mirror. According to this method, the change in the distance between the image and the photographing lens due to the floating of the image moves the mirror, so that the optical path length is kept constant, and the magnification and the like do not change.
When the image of the raised document is captured by changing the tilt angle of the mirror and changing the capturing position, the position of the captured information is shifted from the regular position when the document is flat.
This is because when the document is flat, if the scanning pitch is performed regularly, the captured information will be an image with a regular pitch, but if the mirror and the capturing position are changed, the image will not always be a regular pitch.
This is because the drive source for driving the mirror and scanning the optical system is generally a step motor and cannot be controlled in an analog manner. This means that it is necessary to collate the preceding and following scan information, create intermediate information, and create position information.
By providing a plurality of distance measuring sensors at right angles to the scanning direction and averaging the distances, it is possible to set a better mirror angle and capturing position for capturing data in a direction perpendicular to the scanning direction. In addition, when there is a large swell in the right-angle direction, good information can be obtained by dividing the data in the right-angle direction into several ranges.
As described above, the image capturing operation requires more time than the normal copying operation. Therefore, it is possible to disable the operation when copying is required without being concerned with the quality of the copy, and to detect the floating of the image beforehand so that if the original does not float, the copy operation can be quickly started. I do.
[0011]
In each of the above embodiments, an example of the configuration of the image reading apparatus alone has been described. However, the image reading apparatus of the present invention may be used as a reading apparatus of an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile apparatus. Can be applied. That is, FIG. 5 is a schematic configuration diagram of an image forming apparatus provided with the image capturing / imaging unit A of the present invention. In this image forming apparatus, a document feeder 40 is arranged on a document table 1 on the upper surface of the apparatus main body 30. The apparatus main body 30 includes an image capturing / imaging unit A, an image forming unit B, a paper feeding unit C, a writing optical system D, and an electrical unit (not shown). The image forming unit B includes a photoconductor 31 and a charging unit 32, an exposing unit 33, a developing unit 34, a transfer unit 35, and a fixing unit 36 disposed around the photoconductor 31.
The image data of the document on the document table 1 read by the image capturing / imaging unit A is irradiated as a laser beam onto the photoconductor 31 by the writing optical system D to form an electrostatic latent image. The electrostatic latent image is visualized by the developing unit 34, and the toner image is transferred onto a transfer sheet fed from the sheet feeding unit C, fixed, and then discharged out of the apparatus.
By applying the image capturing / imaging unit A of the present invention to an image forming apparatus having such a configuration, it is possible to improve the image quality due to the excellent reading effect shown in each of the above embodiments.
[0012]
【The invention's effect】
As described above, according to the first aspect, the presence or absence of the floating of the document and the height of the floating of the document can be detected by the distance measuring sensor, thereby enabling the image correction.
According to the second aspect, it is possible to take in information from a direction as perpendicular as possible to a floating document (or a tilted document), and to input an image in which character distortion and compression have been corrected.
According to the third aspect, it is possible to acquire information from a direction perpendicular to the original as much as possible with respect to a floating original or a tilted original. You can do it.
According to the fourth aspect, it is possible to correct a phenomenon in which the focus is blurred due to the floating document surface, and it is possible to obtain an in-focus image.
According to the fifth aspect, this is an item necessary for a surface whose inclination changes in a positive / negative relationship with respect to the reference angle, such as a surface change of the document surface over both pages of the book.
According to the sixth aspect, the inclination direction of the surface can be known from the measurement of the floating amount, the length of the data in the scanning direction can be corrected, and an accurate flat developed document can be created.
According to the seventh aspect, the horizontal development dimension of the document can be known from the measurement of the floating amount, and the length of the data in the scanning direction can be corrected, so that an accurate planar development document can be created.
According to the eighth aspect, the focusing can be performed without using the change of the photographing lens system, whereby the image magnification correction can be omitted.
[0013]
According to the ninth aspect, it is possible to correct a phenomenon in which the focus is blurred due to the floating document surface, and it is possible to obtain an in-focus image.
According to the tenth aspect, since the tilt angle of the mirror and the operation amount of the capturing unit are step-like movements, the scan information of the document does not always match the information obtained in a flat state, so Compare and create intermediate information.
According to the eleventh aspect, by providing a plurality of distance measuring sensors at right angles to the scanning direction and averaging the distances, it is possible to set a better mirror angle and a capturing position for capturing data in the direction perpendicular to the scanning direction.
According to the twelfth aspect, when there is a large swell also in the right-angle direction, good information can be obtained by dividing the data in the right-angle direction into several ranges.
According to the thirteenth aspect, when a document (book or the like) has a swell (difference in floating amount) in a direction perpendicular to the scanning direction and does not fit within the same focal depth, a plurality of capturing operations are performed. Is performed in a range in which does not fit, and better information can be obtained.
According to the fourteenth aspect, it is possible to provide an image forming apparatus that exerts the functions and effects based on each of the above aspects.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an image capturing and imaging unit of an image reading apparatus according to the present invention.
FIG. 2 is a schematic diagram showing a distance measuring sensor and a distance measuring ray.
FIG. 3 is a schematic diagram illustrating a method for obtaining a document surface inclination and a document development length from distance measurement data.
FIG. 4 is a schematic diagram illustrating a correction amount of a tilt angle of a first mirror surface when a normal direction of a surface of a document changes.
FIG. 5 is a configuration explanatory diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 6 is a schematic diagram showing an image forming system portion of a general scanner.
[Explanation of symbols]
Reference Signs List 1 platen, 2 image capture unit, 3rd mirror, 4 mirror unit, 5 imaging lens system, 6 CCD, 7 distance measuring sensor, 10 document, 11 light source, 12 CCD position sensor, A scanner unit, b Path of the distance measuring ray when the document 10 is separated from the document table 1 and floats, c Path of the distance measuring ray when the document is in close contact with the document table surface

Claims

An image reading apparatus that has a scanner unit that moves along the lower surface of the platen and reads an image of a document set on the platen, wherein the image reading device includes a distance measuring sensor that is integrally attached to the scanner unit. Image reading device.

2. The image reading apparatus according to claim 1, wherein the distance measuring sensor measures a distance in a scanning direction and an entire range of one document, and measures a floating amount of the document surface from the document table.

The scanner section is arranged to form an image on a CCD sensor after reflecting the original image through a first mirror and a condensing lens, and the first mirror that first reflects the image of the original image is a reflective mirror. 2. The image reading device according to claim 1, wherein the image reading device has a structure that can change the angle.

The image reading device according to claim 3, wherein the first mirror has a structure capable of moving back and forth in a direction of an optical axis with respect to a condenser lens and a CCD.

5. The image reading apparatus according to claim 4, wherein the reflection angle of the first mirror always keeps a constant reference angle, and the angle which can be changed with respect to the reference angle can be increased or decreased and can be changed in both directions.

The inclination of the document surface is calculated based on the amount of operation of the CCD and the lens unit by the scanning operation of the image reading device and the amount of document floating, and the reflection angle of the first mirror is changed to an angle corresponding thereto. The image reading device according to claim 2.

By calculating the document length in the scanning direction of the document surface from the document floating amount measured by the scanning amount measured by the distance measuring sensor, and by replacing the scan data with a length corresponding to the operation amount of the scanner unit, 3. The image reading apparatus according to claim 2, wherein compression of data in a scanning direction due to floating of a document surface is corrected.

In response to a change in the tilt angle of the mirror reflecting surface due to the tilt of the document surface and a change in the length of the focal plane in the optical axis direction due to the floating of the document, the distance between the CCD and the document surface does not change. 4. The image reading device according to claim 3, wherein the distance of the first reflection surface is changed.

9. The image reading apparatus according to claim 8, wherein the correction of the length change in the optical axis direction is performed by a reflection mirror subsequent to the first mirror.

Although the relationship between the scanner capture position and the capture data is deviated by the correction, correction data is created by performing position correction of data assuming a virtual plane, and by performing weight complementation of adjacent data, and correcting deviation. The image reading apparatus according to claim 7, wherein the image reading is performed.

2. The image reading apparatus according to claim 1, wherein a plurality of the distance measurement sensors are provided in a direction perpendicular to a scanning direction, and also measure a change in a floating amount of the document in a direction perpendicular to the scanning direction of the document.

When the difference between the measured floating amounts of the plurality of sensors is large and does not fall within the allowable depth of the photographing lens system, the video data is created by re-combining a part of the image of the part that does not fit and then synthesizing. 9. The image reading device according to 8.

The copier and the scanner have a configuration that allows the user to select whether or not to perform the correction operation. When the correction operation is started, the inclination of the document surface is calculated, and the angle of the first mirror is adjusted to an angle corresponding to the inclination. 12. The image reading apparatus according to claim 11, wherein the operation of changing the reflection angle is started after the measurement of the floating amount of the entire original document is completed, and the floating range is specified.

An image forming apparatus comprising at least the image reading device according to claim 1, an image forming unit, and a sheet feeding unit.