JP2005051295A - Original reader and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily confirm whether an abnormality image is produced owing to dust and dirt present in a reading optical path of white reference faces 239, 244, 409. <P>SOLUTION: The original reader is provided with: imaging apparatuses (232 to 236, 207/408) for reading an image of an original and generating an image signal; a means (209/209a) for converting the image signal into digital data, that is, image data; a memory means (215/255a) for storing white reference face data resulting from reading the white reference faces (239/409) by the imaging apparatuses; and a means (216/216a) for applying shading correction to the image data resulting from reading the original by the imaging apparatuses by using the white reference face data of the memory means. The reader also includes: a nonvolatile memory (214/255a) for storing the white reference face data; a means (217/256a) for calculating a difference of the white reference face data resulting from reading the white reference face (239/409) by the imaging apparatuses from the white reference face data in the nonvolatile memory; and a means (79) for outputting an image of the difference being image data. (Refer to Fig.3, 11, 19 (not shown here)). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１３３】
操作ボード２２０の初期設定キー８０ｄが押されたときには、操作ボード２２０は、液晶タッチパネル７９の表示を図１３に示す初期設定メニュー画面に切換える。このメニュー画面上の「スキャナ初期設定」ボタンをクリックすると、操作ボード２２０がその液晶タッチパネル７９に、スキャナ初期設定のメニュー画面を表示する。該メニュー画面には、「白基準面の読取テスト」の項目があり、これをユーザがクリックすると、「白基準面の読取テスト」コマンドをシステムコントローラ３１ａがＣＰＵ２５４に与える。このコマンドに応答して、ＣＰＵ２５４が、「白基準面の読取テスト」を実行する。
【０１３４】
図１４に、「白基準面の読取テスト」の内容を示す。これに進むとＣＰＵ２５４は、ホームポジションＨＰから第１および第２キャリッジの往走査駆動を開始して（ステップ１）、第１ミラー２３３の読取視野に基準白板２３９が入るタイミングで、読取処理２１３に与えるシェーディングゲート信号を”Ｈ”から”Ｌ”に切換え、基準白板２３９の中心あたりに読取視野が進んだタイミングで補正ゲート信号を”Ｈ”から”Ｌ”に切換えて、両信号が”Ｌ”の間に、読取処理２１３により、「白基準面データの更新１」を行う（３１，３２）。「白基準面データの更新１」（３２）では、基準白板２３９の表面の画像データを読取って、１ライン分の読取画像データを、白基準面データとして揮発性メモリ２１５に更新書込する。そしてキャリッジをＨＰに戻す（３３）。ＨＰは、原稿読取窓であるガラス２４０を通して、表面シートスルー読取を行うことができる位置である。
【０１３５】
次にＣＰＵ２５１は、読取処理２１３（図１１）で差分演算を行って、差分値を画像濃度すなわち画像データとして、操作ボード２２０の液晶タッチパネル７９に表示する（３４）。このとき読取処理２１３の差分演算２１７は、不揮発性メモリ２１４より７ビット構成の白基準面データを読み出して上位桁方向の桁シフトにより８ビットデータにして、すなわち読み出しデータ値の２倍を表す白基準面データに変換して、この白基準面データに対する、揮発性メモリ２１５に更新書込みした白基準面データの差分値を算出する。差分値の算出を次に記す：
Ｄｋｎ：揮発性メモリ２１５に蓄積した白基準面データ（８ビット），
ｎは１〜７２００，
Ｄｆｎ：不揮発性メモリ２１４に蓄積した白基準面データ（７ビット），
Ｓｎ ：差分データ，
Ｓｎ ＝｜（Ｄｆｎ×２）−Ｄｋｎ｜。
【０１３６】
差分値データＳｎは、通常の原稿画像データとしてセレクタ２１８および変倍処理２１９を経て、更にＡＣＰで画像処理されてＭＥＭに蓄積され、そして操作ボード２２０の液晶タッチパネル７９に、画像として表示される。図１９に表示例を示す。液晶タッチパネル７９の「基準白板の汚れ」と付記したブロックに、差分値データが複数ラインに及んで繰返し書込表示されるが、図１９では、基準白板２３９に汚れを生じていないため、画像は現れていない。図１９に示す液晶タッチパネル７９に表示された主走査画素位置スクロール矢印をユーザがクリックすることにより、１ライン上の表示領域が変更され、これにともなって横軸の主走査画素位置数字も切り換る。
【０１３７】
次にＣＰＵ２５４は、ガラス２４０を通して表面シートスルー読取を行ない、読取った画像データを揮発性メモリ２１５に更新書込する（３５）。ここでは、原稿の送給を行わないので、搬送ドラム２４４の白色表面を読取った白基準面データが揮発性メモリ２１５に書きこまれる。一方、不揮発性メモリ２５５には、以前に搬送ドラム２４４の白色表面を読取った白基準面データの、上位７ビット（読取データ値の１／２を表わすデータ）が白基準面データとして蓄積されている。次にＣＰＵ２５１は、読取処理２１３の差分演算２５６を用いて、不揮発性メモリ２５５より７ビット構成の白基準面データを読み出して上位桁方向の桁シフトにより８ビットデータにして、すなわち読み出しデータ値の２倍を表す白基準面データに変換して、この白基準面データに対する、揮発性メモリ２１５に更新書込みした白基準面データの差分値を算出する。差分値データは、通常の原稿画像データとしてセレクタ２１８および変倍処理２１９を経て、更にＡＣＰで画像処理されてＭＥＭに蓄積され、そして操作ボード２２０の液晶タッチパネル７９に、画像として表示される（３６）。図１９に表示例を示す。液晶タッチパネル７９の「表面読取の汚れ」と付記したブロックに、差分値データが複数ラインに及んで繰返し書込表示される。図１９には、搬送ドラム２４４の表面からＣＣＤ２０７に至る光路に汚れ又はゴミがあることを表している。
【０１３８】
次にＣＰＵ２５４は、撮像装置４０８による裏面シートスルー読取で白色背板４０９の読取を行ない、読取った画像データを揮発性メモリ２５７に更新書込する（３７）。一方、不揮発性メモリ２２５５ａには、以前に白色背板４０９の白色表面を読取った白基準面データの、上位７ビット（読取データ値の１／２を表わすデータ）が白基準面データとして蓄積されている。次にＣＰＵ２５１は、読取処理２１３ａの差分演算２５６ａを用いて、不揮発性メモリ２５５ａより７ビット構成の白基準面データを読み出して上位桁方向の桁シフトにより８ビットデータにして、すなわち読み出しデータ値の２倍を表す白基準面データに変換して、この白基準面データに対する、揮発性メモリ２５７に読込んだ白基準面データの差分値を算出する。差分値データは、通常の原稿画像データとしてセレクタ２１８ａおよび変倍処理２１９ａを経て、更にＡＣＰで画像処理されてＭＥＭに蓄積され、そして操作ボード２２０の液晶タッチパネル７９に、画像として表示される（３８）。図１９に表示例を示す。液晶タッチパネル７９の「裏面読取の汚れ」と付記したブロックに、差分値データが複数ラインに及んで繰返し書込表示される。図１９には、白色背板４０９の表面から撮像装置４０８の内部の撮像素子に至る光路に汚れあるいはゴミがないことを表している。
【０１３９】
次にＣＰＵ２５４は、システムコントローラ３１ａから、操作ボード２２０の液晶パネル７９に表示した「印刷」，「更新」あるいは「終了」の、ユーザによるクリックに応答する「印刷」，「更新」あるいは「終了」のコマンドが到来するのを待つ（３９，４１，４４）。「印刷」がクリックされるとシステムコントローラ３１ａが、ＭＥＭに蓄積した各差分データに印刷出力のための処理を施して、同一ライン情報を繰返しプリンタ１００に出力して、１枚の用紙上にプリントアウトする（３９，４０）。大略で、図１９に示す液晶タッチパネル７９上の３個の表示ブロックを、１ライン長全体を表わすように広げた形の画像が、用紙上に印刷される。
【０１４０】
「更新」コマンドが到来するとＣＰＵ２５４は、揮発性メモリ２１５にある、表面シートスルー読取による搬送ドラム２４４の白色表面読取の白基準面データ（８ビット）の上位７ビットを摘出して、不揮発性メモリ２に書込み、揮発性メモリ２５７にある撮像装置４０８の裏面シートスルー読取による白色背板４０９の白色表面読取の白基準面データ（８ビット）の上位７ビットを摘出して、不揮発性メモリ２に書込み、そして、キャリッジを走査駆動して基準白板２３９の白色表面を読取って不揮発メモリ２１５に書込みキャリッジをＨＰにもどしてから揮発性メモリ２１５にある基準白板２３９の白色表面の白基準面データ（８ビット）の上位７ビットを摘出して、不揮発性メモリ２１４に書込む４１，４２）。すなわち不揮発性メモリ２１４，２５５および２５５ａの白基準面データを更新する。そして、レジスタＮｓａの原稿読取積算値Ｎｓａを０に初期化する（４３）。
【０１４１】
「終了」コマンドが到来するとＣＰＵ２５４は、「白基準面の読取テスト」を終了する（４４）。
【０１４２】
なお、工場出荷時すなわち基準白板２３９，搬送ドラム２４４および白色背板４０９のいずれも新品でピカピカで、いずれの読取光路にも汚れやゴミがないときに、出荷テスト要員が、上述の「白基準面の読取テスト」を指示し更に「更新」を指示することにより、不揮発性メモリ２１４，２５５および２５５ａには、それぞれ基準白板２３９，搬送ドラム２４４および白色背板４０９の表面を読取った白基準面データが格納されている。
【０１４３】
各基準面および読取光路に汚れやゴミ等がない場合、白基準面データは、図１６に示すような状態であるが、汚れあるいはゴミ付着が発生すると、図１７に示すように異常低濃度ピークが現れ、その差分演算の結果は、図１８に示すものとなる。図１６から図１８を参照すると、ゴミや汚れの影響がない場合は、画像は全面白のデータとなるが、ゴミや汚れの影響があった場合は、図１９に示すように、汚れに対応する位置に黒縦スジが現れる。このことにより、ゴミや汚れの影響が一目瞭然に確認可能とすることができる。
【０１４４】
例えば、図１２に示す「表面のシートスルー読取り」（８）又は「裏面のシートスルー読取り」（１６）によって異常画素が検出されたとき、あるいは定期メンテナンスで、サービスマン等がメンテナンス（基準面，読取光路のクリーニング）を行ったあとに、上述の「白基準面の読取テスト」を指示入力することにより、基準面，読取光路のゴミや汚れがうまく除去できたかを確認することができる。もしクリーニング後においても黒縦スジが認められる場合は、クリーニングした範囲外にまだゴミ等が入り込んでいるものとして、更に装置内部のクリーニング迄実施する判断をすることができる。「白基準面の読取テスト」の結果、ゴミや汚れ対応の黒縦スジがないと、「更新」をクリックして、不揮発性メモリの白基準面データを、最新の読取データに更新しておくことができる。
【０１４５】
図２０に、読取処理２１３，２１３ａの第１変形例を示す。この変形例は、変倍処理２１８，２１８ａを、白基準面データを格納する不揮発性メモリ２１４，２５５および２５５ａの前段に配置して、不揮発性メモリ２１４，２５５および２５５ａに書込む白基準面データの１ライン分の数を、変倍処理２１８，２１８ａによる１画素おきの間引き（５０％の縮小）により、半分に減量し、不揮発性メモリ２１４，２５５および２５５ａから白基準面データを読出す時には変倍処理２１８，２１８ａによる１画素の読み出し白基準面データを２画素に割りつける補間（２００％の拡大）により２倍に拡張する。その他の機能は、図１１に示す読取処理２１３，２１３ａと同様である。
【０１４６】
読取処理２１３，２１３ａの第２変形例では、第１変形例と同様に、不揮発性メモリ２１４，２５５および２５５ａに書込む白基準面データの１ライン分の数を、変倍処理２１８，２１８ａによる１画素おきの間引き（５０％の縮小）により、半分に減量する。そして、差分演算２１７，２５６，２５６ａで、不揮発性メモリ２１４，２５５および２５５ａから読み出した白基準面データは拡張することなく、基準白板２３９，搬送ドラム２４４，白色背板４０９の新たな読取で得る白基準面データの１ライン分の数を、変倍処理２１８，２１８ａによる１画素おきの間引き（５０％の縮小）により、半分に減量して、差分演算に用いる。この第２変形例での差分演算は、
Ｄｋｎ：基準面読取りの白基準面データ，ｎは１〜３６００，
Ｄｆｎ：不揮発性メモリに蓄積した白基準面データ，
Ｓｎ ：差分データ，
Ｓｎ ＝｜Ｄｆｎ−Ｄｋｎ｜
となる。
【０１４７】
この差分データＳｎが画像データとしてＡＣＰに転送されて液晶タッチパネル７９に表示されるので、液晶タッチパネル７９まで転送されるデータ量が半分になる。このことにより本来具備している変倍処理を活用させながら、不揮発性メモリのサイズを小さくすることが可能となる。
【０１４８】
【発明の効果】
白基準面（２３９，２４４，４０９）に汚れがあると、汚れの部位の差分値が大きく、それが高濃度画像で出力される。この出力の目視により、白基準面から撮像素子に至る光路にゴミや汚れがあるかを目視確認できる。そのことによって、ゴミや汚れが原因で異常画像を発生してしまうという装置の状態を正確に把握することが可能となり、サービスマンのメンテナンス時の確認作業効率が向上する。
【図面の簡単な説明】
【図１】本発明の１実施例の、複合画像処理機能があるフルカラー複写機の外観を示す拡大正面図である。
【図２】図１に示すカラープリンタ１００の拡大縦断面図である。
【図３】図１に示すカラースキャナ２１０およびＡＤＦ２３０の拡大縦断面図である。
【図４】図１に示す複写機内の、画像処理システムの構成を示すブロック図である。
【図５】図４に示す画像データインターフェース制御ＣＤＩＣの構成を示すブロック図である。
【図６】図４に示す画像メモリアクセス制御ＩＭＡＣの構成を示すブロック図である。
【図７】図４に示す画像データ処理器ＩＰＰの画像データ処理機能を示すブロック図である。
【図８】図１に示す操作ボード２２０の一部の拡大平面図である。
【図９】図１に示す原稿スキャナ２１０，ＡＤＦ２３０の画像読み取り電気回路系の構成を示すブロック図である。
【図１０】図９に示すスキャナ制御回路２０６およびモータ制御ユニット２６０の構成を示すブロック図である。
【図１１】図９に示す読取処理２１３，２１３ａの機能構成を示すブロック図である。
【図１２】図１０に示すＣＰＵ２５４の、画像読取制御の概要を示すフローチャートである。
【図１３】図８に示す初期設定キー８０ｄが操作されたときに操作ボード２２０が液晶タッチパネル７９に表示するメニュー画面を示す平面図である。
【図１４】図１３に示す「スキャナー初期設定」がクリックされ、それに応答して走査ボード２２０が液晶タッチパネル７９に表示したメニュー画面上の「白基準面の読取テスト」がクリックされたときに、図４に示すシステムコントローラ３１ａおよび図１０に示すＣＰＵ２５４が協働して実行する「白基準面の読取テスト」の内容を示すフローチャートである。
【図１５】図３に示すスキャナ１０の、コンタクトガラス２３１上の原稿の画像読取走査の間に発生するタイミング信号のレベル変化を示すタイムチャートである。
【図１６】基準白板２３９，搬送ドラム２４４，白色背板４０９の読取データである１ライン分の白基準面データの分布の概要を示すグラフである。
【図１７】読取面又は読取光路に汚れ又はゴミがある場合の１ライン分の白基準面データの分布の概要を示すグラフである。
【図１８】図１６に示す基準の白基準面データに対する図１７に示す現在読取した白基準面データの差分値の１ライン上の分布を示すグラフである。
【図１９】図８に示す液晶タッチパネル７９に表示される差分データの画像表示を示す平面図である。
【図２０】図９に示す読取処理２１３，２１３ａの第１変形例を示すブロック図である。
【符号の説明】
１：感光体 ２：帯電装置
３：現像装置 ４：クリーニング装置
５：除電装置 ６：露光装置
７：第１転写ベルト
８〜１０：ローラ
１１：第１転写手段
１２：クリーニング装置
１３：第２転写ベルト
１４〜１６：回転ローラ
１７：第２転写手段
１８：クリーニング装置
１９：チャージャ
２０：用紙（記録媒体）
２１，２２：給紙カセット
２３：定着器 ２４：排紙ガイド
２５：排紙ローラ
２６：排紙スタック
２７：補給トナー収納部
２８：カートリッジ
２９：フレーム ３０：開閉支軸
３１，３２：給紙ローラ
３３：レジストローラ
２２１，２２５：ロータリエンコーダ
２２４：ステッピングモータ
２３１：原稿台ガラス ２３２：照明ランプ
２３３：第１ミラー ２３４：第２ミラー
２３５：第３ミラー ２３６：レンズ
２０７：イメージセンサ ２３８：ステッピングモータ
２３９：基準白板 ２４０：ガラス
２４１：原稿トレイ ２４２：ピックアップローラ
２４３：レジストローラ対 ２４４：搬送ドラム
２４５：押さえローラ ２４６，２４７：排紙ローラ
２４８：排紙トレイ兼用の圧板
２４９：基点センサ ２５０：軸
２５１：スケール ２６０：モータ制御ユニット
４０８：撮像装置 ４０９：白色背板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a document reading apparatus and an image forming apparatus using the same, and can be used for, for example, a document scanner, a copying machine, and a facsimile.
[0002]
[Prior art]
The number of documents handled in the office continues to increase, and in order to improve the efficiency of document management, there is an increasing need for electronic filing systems that use a manuscript scanner to drop paper documents into binarized electronic image data. ing. In an original scanner equipped with an auto document feeder, paper dust or the like is generated in the paper passing path due to rubbing during paper passing. If a large amount of paper passes, dust and dirt such as paper dust enter the paper passing path. accumulate. A streaky abnormal image is generated due to dust and dirt on the scanning line. In order to prevent abnormal images due to dust and dirt adhering to the scanning line, servicemen and users can clean the paper passing route by the number of paper passing to prevent the occurrence of abnormal images. The frequency of occurrence of paper dust is also affected by “paper quality / paper thickness” and “use environment such as temperature and humidity”, and it is not very accurate to clean by looking at the number of sheets passed. When the above dust and dirt enter the shading correction reference data, streaky abnormal images are particularly likely to occur.
[0003]
In the document image reading described in Japanese Patent Application Laid-Open No. 09-074465, in the sheet-through document reading in which the document is fed and driven to read the document image with a stationary imaging device, the white reference plate in the document moving area is used. When reading and shading correction, the white reference plate is easily soiled and black stripes are likely to occur in the read image. Therefore, the reading optical system is provided for scanning the reading optical system along the contact glass on which the document is placed and fixed. The white reference plate outside the document movement area is read immediately before reading the sheet-through document and used for shading correction.
[0004]
Japanese Patent Application Laid-Open No. 2002-165074 discloses an image reading apparatus that reads a sheet-through background plate (document back support plate) through a reading window and detects stains on the reading window based on the read data. Is described.
[0005]
Japanese Patent Application Laid-Open No. 2000-115488 detects image dust position by comparing shading-corrected read data with blank paper read data, and corrects the read data at the dust position based on the data of neighboring pixels. Is disclosed.
[0006]
[Problems to be solved by the invention]
Neither of them can be a perfect measure, so it is the best countermeasure that a serviceman or user performs a paper passing route, cleaning of the reference white plate, re-covering the reference white plate, and the like. However, the cleaning of the paper passing path and the reference white plate may cause dust and dirt to adhere to the user and may cause new dirt on other parts. In addition, the user cannot disassemble and remove the dust that has entered the inside of the machine from the viewpoint of safety. Therefore, the complaint reaches the service store from the user.
[0007]
When the service person removes the dust that has entered the machine, the machine needs to be disassembled and the time required for maintenance is inevitably increased. During this time, the device becomes unusable and the user's work efficiency is significantly degraded. In addition, since the normal service man performs the cleaning of the paper passage route within the reach of the outside of the device, if the presence or absence of dust still entering the device after cleaning cannot be accurately determined, the maintenance is finished as it is, and the user will complain later. May be received again, and the situation may be further deteriorated from the viewpoints of user convenience and serviceman maintenance.
[0008]
An object of the present invention is to make it easy to confirm whether an abnormal image is generated due to dust or dirt in reading a white reference surface.
[0009]
[Means for Solving the Problems]
(1) An image pickup device (232-236, 207/408) that reads an image of a document and generates an image signal, means (209 / 209a) for converting the image signal into digital data, that is, image data, and the image pickup device is a white reference The memory means (215 / 255a) for storing the white reference plane data obtained by reading the plane (239/409), and the image data obtained by reading the document by the image pickup device is used for shading using the white reference plane data of the memory means. In a document reading device comprising a correction means (216 / 216a),
A non-volatile memory (214 / 255a) for storing white reference plane data;
Means (217 / 256a) for calculating a difference between the white reference plane data obtained by the imaging device reading the white reference plane (239/409) and the white reference plane data of the nonvolatile memory; and
Means for outputting the difference as image data (79);
A document reading apparatus (FIGS. 3, 11, and 19), comprising:
[0010]
In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the corresponding matter of the Example shown in drawing and mentioned later in parentheses was added as reference for reference. The same applies to the following.
[0011]
According to this, if there is dirt on the white reference surface, the difference value of the dirt part is large, and it is output as a high density image. By visually checking this output, it can be visually confirmed whether there is dust or dirt in the optical path from the white reference plane to the image sensor. As a result, it is possible to accurately grasp the state of the apparatus that causes an abnormal image due to dust or dirt, and the efficiency of confirmation work at the time of maintenance by a service person is improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(2) input means (80d, 79) for instructing a white reference surface reading test; and
Read test control for reading the white reference plane by the imaging apparatus in response to the white reference plane reading test instruction and outputting the image as the difference calculated by the difference calculation means by the output means (79). The document reading device according to (1), further comprising means (220, 31a, 206).
[0013]
According to this, a user or a service man simply inputs a white reference surface reading test instruction using the input means (80d, 79), and a smear image of the white reference surface is output. Improves the efficiency of checking the dirt on the white reference surface.
[0014]
(2a) The document according to (1) or (2), further comprising: means for detecting abnormal pixels based on image data obtained by performing the shading correction on the white reference plane data obtained by reading the white reference plane by the imaging device. Reader. According to this, when dirt or dust occurs in the optical path from the white reference plane to the image sensor, the part is detected as an abnormal pixel. In response to this detection, when an instruction for a white reference surface reading test is input using the input means (80d, 79), a smear image of the white reference surface is output, and confirmation is easy. Furthermore, immediately after the work of cleaning the optical path from the white reference surface to the image sensor, the input of the white reference surface reading test can be confirmed to be removed using the input means (80d, 79).
[0015]
(3) Contact glass (231) on which an original is placed; an image pickup apparatus that reads an image of an original placed on and fixed to the contact glass by an optical system or an image sensor parallel to the contact glass and generates an image signal (232-236, 207); and a white reference surface (239) disposed outside the document scanning area and readable by the imaging device (1) or (2). FIG. 3). This is an embodiment of an optical scanning method capable of reading a book document. The presence or absence of dirt or dust generated with time in the optical path from the white reference surface (239), which is the surface of the reference white plate 239, to the image sensor 207 can be easily confirmed.
[0016]
(4) Document reading window (240); Document transfer means for feeding the document into the document reading window and passing it through the document reading window (242-247); Reading the image of the document crossing the document reading window through the document reading window (1) to (3), comprising: an imaging device (232-236, 207) that generates image data; and a white reference surface (239) that is disposed outside the original reading window and can be read by the imaging device. The document reading apparatus according to any one of the above.
[0017]
In this embodiment, the white reference surface (239) is not the surface of the white back plate 244 (conveying drum) facing the document reading window (240), but the surface of the reference white plate 239. . The reason is that the white back plate 244 and the document reading window (240) are likely to become dirty and dust is likely to adhere, thereby avoiding erroneous shading correction. Although the reference white plate 239 may become dirty, it is overwhelmingly less dirty than the white back plate 244 and the original reading window (240). However, according to the present embodiment, it is easy to confirm the presence or absence of dirt or dust generated over time in the optical path from the white reference surface, which is the surface of the reference white plate 239, to the image sensor 207.
[0018]
(5) Document transport means (242-247) for feeding the document on the sheet feed table (141) and transporting it to the sheet discharge table (248); an image pickup device for reading an image of the transported document and generating an image signal ( 232-236, 207/408); and a white reference surface (244/409) positioned on the back of the document that is transported facing the imaging device, and any one of (1) to (3) above The document reading device described in 1.
[0019]
This is an embodiment of the sheet-through reading method, and the white reference plane (244/409) is the white back plate 244 (conveying drum) or the white back plate 409 facing the document reading window 240 or the imaging device 409. The white back plate 244, the document reading window 240, the white back plate 409, and the imaging device 408 are easily contaminated. According to this embodiment, it is easy to check the presence or absence of dirt or dust that occurs over time in the optical path from the white back plate 244/409 to the image sensor 207 / image sensor in the image pickup apparatus 408.
[0020]
(5a) contact glass (231) for placing a document;
A first imaging device (232-236, 207) that reads an image of a document placed and fixed on the contact glass and generates an image signal by mechanical scanning of an optical system or an image sensor parallel to the contact glass;
A first white reference surface (239) disposed outside the document scanning area and readable by the first imaging device;
A document reading window (240) which is disposed outside the document scanning area and can be seen through by the first imaging device;
Document transport means (242-247) for feeding a document into the document reading window and passing the document across the document reading window;
A second white reference surface (244) located on the back of the document to be transferred facing the document reading window;
First memory means (215) for storing white reference plane data obtained by reading the first white reference plane by the first imaging device;
First shading correction means (216) for correcting image data read by the first imaging device using white reference plane data of the first memory means;
A first non-volatile memory (214) for storing a first set of white reference plane data;
The first imaging device calculates a first set of differences between the first white reference plane data read from the first white reference plane (239) and the first set of white reference plane data in the first nonvolatile memory (214). First difference calculation means (217);
A second non-volatile memory (255) for storing a second set of white reference plane data;
The first imaging device calculates a second set of differences of the second white reference plane data read from the second white reference plane (244) with respect to the second set of white reference plane data in the second nonvolatile memory (255). Second difference calculation means (256); and
A document reading device comprising means (79) for outputting the difference between the first set and the second set as image data.
[0021]
This is a mode of combination of the above (3) and (5), and the effects described in the above (3) and (5) can be obtained.
[0022]
(5b) Further, a second image pickup device (408) that reads an image of a back surface of the document transported by the document transport means and faces the document reading window (240) and generates an image signal;
A third white reference surface (409) located on the back of the document to be transferred facing the second imaging device;
3rd memory means (255a) which memorize | stores the white reference plane data which the 2nd imaging device (408) read the 3rd white reference plane (409);
Second shading correction means (216a) for correcting image data read by the second imaging device (408) using white reference plane data of the third memory means (255a);
The third set of differences between the third white reference plane data obtained by the second imaging device (408) reading the third white reference plane (409) and the third set of white reference plane data in the third nonvolatile memory (255a). A third difference calculating means (256a) for calculating
The image output means (79) outputs the image as a third set of differences as image data; the document reading apparatus according to (5a) above. This is a mode in which the back side reading imaging device (408) and the white back plate 409 are added to the above (5a) in the mode (5), and the operational effects described in the above (3) and (5) are obtained. Either front side reading or back side reading can be obtained.
[0023]
(5c) The initial white reference plane data of the non-volatile memory is white reference plane data obtained by reading the white reference plane by the image pickup apparatus before the document reader is shipped from the factory; the above (1) to (5b) The document reading apparatus according to any one of the above. According to this, since the white reference plane data obtained by reading the white reference plane when it is new becomes the initial value of the nonvolatile memory, there is no error in detecting the presence or absence of dirt or dust due to individual differences in the machine, and the machine can be used for the first time. Accurate detection of dirt or dust.
[0024]
(5d) The apparatus according to any one of (1) to (5c), further including means for updating and writing white reference plane data obtained by the imaging device reading the white reference plane in the nonvolatile memory; Reader. According to this, the non-volatile memory is updated to the one representing the current state of the white reference surface as the white reference surface changes over time, so that the detection of the presence or absence of dirt or dust can be accurately stabilized over time. .
[0025]
(5e) The update writing unit performs the update writing when the number of times of document reading reaches a set value; the document reading device according to (5d) above. This is convenient because the white reference plane data of the nonvolatile memory is automatically updated as the number of document readings increases.
[0026]
(5f) The means (79) for outputting the image using the difference as image data is a display (79: FIG. 19); The document reading apparatus according to any one of (1) to (5e) above.
[0027]
(5g) The amount of white reference plane data in the non-volatile memory is smaller than the amount of white reference plane data generated by the imaging device reading the white reference plane; The document reading apparatus according to any one of (1) to (5f) above is calculated. According to this, the capacity required for storing the white reference plane data in the nonvolatile memory can be reduced.
[0028]
(5h) The number of bits (7) constituting each data of the white reference plane data of the nonvolatile memory is the number of bits constituting each data of the white reference plane data generated by the imaging device reading the white reference plane ( 8) less by a (a = 1) than the difference calculating means, the difference between the imaging device for the white reference plane data read from the non-volatile memory and data (8 bits) times 2 a times The difference between the white reference plane data generated by reading is calculated; the document reading apparatus according to (5g) above. According to this, the capacity required for storing the white reference plane data in the nonvolatile memory can be reduced.
[0029]
(5i) The white reference plane data of the nonvolatile memory is a small amount (1/2) of data amount obtained by thinning out the white reference plane data generated by the imaging device reading the white reference plane; Reads the white reference plane data of the non-volatile memory and calculates the difference of the white reference plane data generated by the imaging device reading the white reference plane with respect to the data that has been supplemented with thinning (2 × 1/2) by interpolation The document reading apparatus according to (5g) or (5H) above. Thinning out is a so-called image reduction process, and replenishment is an image enlargement process. This also requires less storage capacity for storing the white reference plane data in the nonvolatile memory.
[0030]
(5j) The difference calculation means reads the white reference plane data of the non-volatile memory, reduces the white reference plane data generated when the imaging device reads the white reference plane to a value that matches the read data amount, and performs the difference. The document reading apparatus according to (5g) above. According to this, the amount of difference data is also small, and the amount of data from difference value calculation to image output can be small.
[0031]
(6) Document reading device (210, 230) according to any one of (1) to (5j); converting image data subjected to shading correction output from the document reading device into image data for printing An image forming apparatus comprising: an image data processing apparatus (ACP); and a printing unit (100) for forming an image represented by the image data for printing on a sheet.
[0032]
According to this, the effect described in any of (1) to (5j) can be obtained in the image forming apparatus.
[0033]
Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.
[0034]
【Example】
FIG. 1 shows a multi-function full color digital copying machine according to an embodiment of the present invention. This full-color copying machine is roughly constituted by units of an automatic document feeder (ADF) 230, an operation board 220, a color scanner 210, and a color printer 100. Note that the operation board 220 and the color scanner 210 with the ADF 230 are units that can be separated from the printer 100. The color scanner 210 includes a control board having a power device driver, sensor input, and controller. Communication with the image data processing device ACP (FIG. 4) of the control board in the machine is performed directly or indirectly to read the document image under timing control.
[0035]
The image data processing device ACP (FIG. 4) is connected to a LAN (Local Area Network) connected to a personal computer PC, and the facsimile control unit FCU (FIG. 4) is connected to a telephone line PN (facsimile communication line). The exchange PBX is connected. The printed paper of the color printer 100 is discharged to the paper discharge stack 26 (FIG. 2).
[0036]
FIG. 2 shows the mechanism of the color printer 100. The color printer 100 of this embodiment is a laser printer. The laser printer 100 includes four sets of toner image forming units a to d for forming images of each color of magenta (M), cyan (C), yellow (Y), and black (black: K). Are arranged in this order along the moving direction (lower right to upper left direction y in the figure). That is, it is a four-drum type full-color image forming apparatus.
[0037]
A static eliminating device 5, a cleaning device 4, a charging device 2, and a developing device 3 are arranged on the outer peripheral portion of the photosensitive member 1, which is a first image carrier that is rotatably supported and rotates in the direction of the arrow. A space for storing optical information emitted from the exposure device 6 is secured between the charging device 2 and the developing device 3. There are four photosensitive members 1 (a, b, c, d), and the components for image formation provided around each are the same. The color of the color material (toner) handled by the developing device 3 is different.
[0038]
The photoconductor 1 as the first image carrier is a photoconductor in which an organic semiconductor layer as a photoconductive material is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm. Part of it is in contact with the first transfer belt 7 which is the second image carrier. A belt-like photoreceptor 1 can also be employed.
[0039]
The first transfer belt 7 is supported and stretched between the rotating rollers 8, 9, and 10 so as to be movable in the direction of the arrow. On the back side (inside the loop), the first transfer means 11 is attached to the photoreceptor 1. It is deployed in the vicinity. A cleaning device 12 for the first transfer belt is disposed outside the belt loop. Unnecessary toner remaining on the surface after the transfer from the first transfer belt 7 is wiped off.
[0040]
The exposure device 6 irradiates the uniformly charged surface of the photoconductor as a latent image with optical information corresponding to full-color image formation by a known laser system. An exposure apparatus comprising an LED array and an image forming means can also be employed. The first transfer belt 7 is a belt having a base of a resin film or rubber having a base thickness of 50 μm to 600 μm, and has a resistance value capable of transferring toner from the photoreceptor 1.
[0041]
On the right side of the first transfer belt 7 in FIG. 2, a second transfer belt 13 as a third image carrier is provided. The second transfer belt 13 is supported and stretched between the rotary rollers 14, 15 and 16 so as to be movable in the direction of the arrow, and a second transfer means 17 is provided on the back side (inside the loop). Outside the belt loop, a cleaning device 18 for the second transfer belt, a charger 19 and the like are provided. After the toner is transferred to the paper, the cleaning device 18 wipes away the remaining unnecessary toner.
[0042]
The first transfer belt 7 and the second transfer belt 13 are brought into contact with each other by the second transfer means 17, the roller 16, and the roller 8 supporting the first transfer belt 7, thereby forming a predetermined transfer nip. The second transfer belt 13 is a belt having a base of a resin film or rubber having a base thickness of 50 μm to 600 μm, and is a belt having a resistance value capable of transferring toner from the first transfer belt 7.
[0043]
The paper 20 as a recording medium is stored in the paper feed cassettes 21 and 22 in the lower part of the figure, and the uppermost paper is conveyed one by one by the paper feed rollers 31 or 32 to the registration rollers 33 through a plurality of paper guides. Is done. Above the second transfer belt 13, a fixing device 23, a paper discharge guide 24, a paper discharge roller 25, and a paper discharge stack 26 are arranged.
[0044]
A storage section 27 that can store replenishment toner is provided above the first transfer belt 7 and below the paper discharge stack 26. The toner has four colors, magenta, cyan, yellow, and black, and is in the form of a cartridge 28. The developing device 3 corresponding to the corresponding color is appropriately supplied by a powder pump or the like.
[0045]
The frame 29, which is a part of the main body, has a structure that can be pivoted and opened around the opening / closing support shaft 30. Therefore, the conveyance path of the recording medium is greatly opened to facilitate the processing of the jammed recording medium (paper). ing.
[0046]
Here, the operation of each unit during duplex printing will be described. First, image formation by the photosensitive member 1 is performed. That is, by the operation of the exposure device 6, light from an LD light source (not shown) passes through an optical component (not shown), and among the photoconductors 1 uniformly charged by the charging device 2, the photoconductor of the image forming unit a. Then, a latent image corresponding to the writing information (information corresponding to the color) is formed. The latent image on the photoreceptor 1 is developed by the developing device 3, and a visible image with toner is formed and held on the surface of the photoreceptor 1. This toner image is transferred by the first transfer means 11 to the surface of the first transfer belt 7 that moves in synchronization with the photoreceptor 1. The remaining toner on the surface of the photoreceptor 1 is cleaned by the cleaning device 4 and discharged by the charge removing device 5 to prepare for the next image forming cycle.
[0047]
The first transfer belt 7 carries the toner image transferred on the surface and moves in the direction of the arrow. A latent image corresponding to another color is written on the photoreceptor 1 of the image forming unit b, and developed with a toner of the corresponding color to become a visible image. This image is superimposed on the visible image of the previous color already on the first transfer belt 7, and finally four colors are superimposed. In some cases, only monochrome black is formed.
[0048]
At this time, the second transfer belt 13 moves in the direction of the arrow in synchronism, and the image created on the surface of the first transfer belt 7 is transferred to the surface of the second transfer belt 13 by the action of the second transfer means 17. The The first and second transfer belts 7 and 13 are moved while the images are formed on the respective photoreceptors 1 of the four image forming units a to d in the so-called tandem format, and the image forming is advanced. Can be shortened.
[0049]
When the first transfer belt 7 moves to a predetermined position, a toner image to be created on another surface of the paper is formed again by the photoconductor 1 in the process as described above, and paper feeding is started. When the paper feed roller 31 or 32 rotates counterclockwise, the uppermost paper 20 in the paper feed cassette 21 or 22 is pulled out and conveyed to the registration roller 33.
[0050]
The toner image on the surface of the first transfer belt 7 is transferred by the second transfer unit 17 to one surface of the sheet fed between the first transfer belt 7 and the second transfer belt 13 through the registration roller 33. Further, the recording medium is conveyed upward, and the toner image on the surface of the second transfer belt 13 is transferred to the other surface of the sheet by the charger 19. At the time of transfer, the sheet is conveyed at a timing so that the position of the image is normal.
[0051]
In this embodiment, the polarity of the toner imaged on the photoreceptor 1 is negative. By applying a positive charge to the first transfer means 11, the toner imaged on the photoreceptor 1 is transferred to the first transfer belt 7. By applying a positive charge to the second transfer unit 17, the toner transferred to the first transfer belt 7 is transferred to the second transfer belt 13. By feeding the paper between the first and second transfer belts 7 and 13 and applying a positive charge to the second transfer means 17, the toner transferred to the first transfer belt 7 is transferred to one surface of the paper, Further, the toner transferred to the second transfer belt 13 is given a positive polarity charge from the transfer charger 19, so that the negative polarity toner on the surface of the second transfer belt 13 is sucked and transferred to the other surface of the sheet. The
[0052]
The paper on which the toner images are transferred on both sides in the above steps is sent to the fixing device 23, where the toner images (both sides) on the paper are melted and fixed at one time, and the upper part of the main body frame is guided by the paper discharge roller 25 through the guide 24. Are discharged to the paper discharge stack 26.
[0053]
As shown in FIG. 2, when the paper discharge units 24 to 26 are configured, the side (page) of the double-sided image that is transferred to the paper later, that is, the surface that is directly transferred from the first transfer belt 7 to the paper is the lower surface. Since the image is placed on the paper discharge stack 26, in order to align the pages, the image of the second page is created first, the toner image is held on the second transfer belt 13, and the first page The image is directly transferred from the first transfer belt 7 to the sheet.
[0054]
The image directly transferred from the first transfer belt 7 to the sheet is a normal image on the surface of the photoconductor, and the toner image transferred from the second transfer belt 13 to the sheet is a reverse image (mirror image) on the surface of the photoconductor. It is exposed as follows. Such image forming order for page alignment and image processing for switching between normal and reverse images (mirror images) are also performed by image data read / write control to the memory MEM by IMAC.
[0055]
After the transfer from the second transfer belt 13 to the paper, a cleaning device 18 including a brush roller, a collection roller, a blade, and the like removes unnecessary toner and paper dust remaining on the second transfer belt 13.
[0056]
In FIG. 2, the brush roller of the cleaning device 18 is in a state separated from the surface of the second transfer belt 13. The structure can swing around the fulcrum 18a and can contact and separate from the surface of the second transfer belt 13. Before the transfer to the paper, the second transfer belt 13 is released when the toner image is carried, and when the cleaning is necessary, the second transfer belt 13 is swung in the counterclockwise direction in FIG. The removed unnecessary toner is collected in the toner storage unit 34.
[0057]
The image forming process in the duplex printing mode in which the “duplex transfer mode” is set has been described above. In the case of duplex printing, printing is always performed by this image forming process. In the case of single-sided printing, there are two types of "single-sided transfer mode by the second transfer belt 13" and "single-sided transfer mode by the first transfer belt 7", and the former single-sided transfer mode using the second transfer belt 13 is set. In this case, a visible image formed by superimposing four colors (or monochromatic black) on the first transfer belt 7 is transferred to the second transfer belt 13 and transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a printing screen on the upper surface of the printed paper discharged to the paper discharge stack 26.
[0058]
When the single-sided transfer mode using the latter first transfer belt 7 is set, a visible image formed by superimposing four colors (or single color black) on the first transfer belt 7 is transferred to the second transfer belt 13. Without being transferred to one side of the paper. There is no image transfer on the other side of the paper. In this case, there is a print screen on the lower surface of the printed paper discharged to the paper discharge stack 26.
[0059]
FIG. 3 shows a document image reading mechanism of the scanner 210 and the ADF 230 attached thereto. The document placed on the contact glass 231 of the scanner 210 is illuminated by the illumination lamp 232, and the reflected light (image light) of the document is reflected by the first mirror 233 in parallel with the sub-scanning direction y. The illumination lamp 232 and the first mirror 233 are mounted on a first carriage (not shown) that is driven at a constant speed in the sub-scanning direction y. Second and third mirrors 234 and 235 are mounted on a second carriage (not shown) driven in the same direction as the first carriage, and the image light reflected by the first mirror 233 is The light is reflected downward (z) by the second mirror 234, reflected in the sub-scanning direction y by the third mirror 235, converged by the lens 236, irradiated to the CCD 207, and converted into an electrical signal. The first and second carriages are driven forward (original scanning) and backward (return) in the y direction using the traveling body motor 238 as a drive source.
[0060]
The scanner 210 is equipped with an automatic document feeder ADF230. The originals stacked on the original tray 241 of the ADF 230 are fed between the conveyance drum (platen) 244 and the pressing roller 245 by the pickup roller 242 and the registration roller pair 243, and are brought into close contact with the conveyance drum 244 and placed on the reading glass 240. , And are discharged onto a discharge tray 248 that also serves as a pressure plate below the document tray 241 by discharge rollers 246 and 247.
[0061]
When the image on the surface of the document passes through the reading glass 240 serving as a document reading window, the image is irradiated by the illumination lamp 232 that is moving immediately below the image, and the reflected light on the surface of the document is optical below the first mirror 233. The CCD 207 is irradiated through the system and subjected to photoelectric conversion. That is, it is converted into RGB color image signals. The surface of the transport drum 244 is a white back plate facing the reading glass 240 and is white so as to be a white reference plane.
[0062]
Further, the image on the back side of the document is read and photoelectrically converted by an image pickup apparatus 408 including a light source and an image pickup device. That is, it is converted into RGB color image signals. There is a white back plate 409 facing the imaging device 408, and the document passes between the imaging device 408 and the white back plate 409.
[0063]
A reference white plate 239 and a base point sensor 249 for detecting the first carriage are disposed between the reading glass 240 and the scale 251 for positioning the document start end. Although the reference white plate 239 reads a document having a uniform density due to variations in individual light emission intensities of the illumination lamp 232, variations in the main scanning direction, sensitivity unevenness for each pixel of the CCD 207, and the like. It is prepared to correct the phenomenon in which read data varies (shading correction).
[0064]
FIG. 4 shows the system configuration of the image processing system of the copying machine shown in FIG. In this system, a color document scanner 210 including a reading unit 211 and an image data output I / F (Interface) 212 is connected to an image data interface control CDIC (hereinafter simply referred to as CDIC) of the image data processing apparatus ACP. Yes. A color printer 100 is also connected to the image data processing apparatus ACP. The color printer 100 receives the writing I / F 134 YMCK recording image data from an image data processor IPP (Image Processing Processor; hereinafter simply referred to as IPP) of the image data processing apparatus ACP, and prints it out by the imaging unit 135. The image forming unit 135 is shown in FIG.
[0065]
The image data processing device ACP (hereinafter simply referred to as ACP) includes a parallel bus Pb, an image memory access control IMAC (hereinafter simply referred to as IMAC), an image memory MEM (memory module; hereinafter simply referred to as MEM), and a hard disk device. An HDD (hereinafter simply referred to as HDD), a system controller 31a, a RAM 34, a nonvolatile memory 35, a font ROM 36, a CDIC, an IPP, and the like are provided. A facsimile control unit FCU (hereinafter simply referred to as FCU) is connected to the parallel bus Pb. The operation board 220 is connected to the system controller 31a.
[0066]
The RGB image signals generated by the CCD 207 of the reading unit 211 and the image pickup device 208 of the image reading device 208 of the color original scanner 210 for optically reading the original are processed on the sensor board unit SBU and converted into RGB image data. In addition, shading correction is performed and the data is sent to the CDIC via the output I / F 212.
[0067]
The CDIC performs communication between the output I / F 212, the parallel bus Pb, and the IPP, and the process controller 131 and the system controller 31a that controls the entire ACP with respect to the image data. The RAM 132 is used as a work area for the process controller 131, and the nonvolatile memory 133 stores an operation program for the process controller 131.
[0068]
In addition to the semiconductor memory MEM, there is an HDD for storing a lot of image data. By using the HDD, there is a feature that an external power source is unnecessary and an image can be held permanently. Many original images can be read by a scanner and held in the HDD, and many document images provided by the PC can be held.
[0069]
Image memory access control IMAC (hereinafter simply referred to as IMAC) controls writing / reading of image data and control data to / from MEM and HDD. The system controller 31a controls the operation of each component connected to the parallel bus Pb. The RAM 34 is used as a work area for the system controller 31a, and the nonvolatile memory 35 stores an operation program for the system controller 31a.
[0070]
The operation board 220 inputs processing to be performed by the ACP. For example, the type of processing (copying, facsimile transmission, image reading, printing, etc.), the number of processings, etc. are input. Thereby, the image data control information can be input.
[0071]
The RGB image data read by the scanner 210 and the CCD 207 of the ADF and the imaging device 208 is subjected to image processing for correcting reading distortion such as scanner gamma correction and filter processing by the IPP, and then stored in the MEM. When printing out MEM image data, IPP performs color conversion of RGB signals to YMCK signals, and performs image quality processing such as printer gamma conversion, gradation conversion, and gradation processing such as dither processing or error diffusion processing. The image data after the image quality processing is transferred from the IPP to the writing I / F 134. The writing I / F 134 performs laser control on the gradation processed signal by pulse width and power modulation. Thereafter, the image data is sent to the image forming unit 135, and the image forming unit 135 forms a reproduced image on the transfer paper.
[0072]
Based on the control of the system controller 31a, the IMAC controls the access of image data, MEM, and HDD, develops print data of a personal computer PC (not shown) connected to the LAN (hereinafter simply referred to as PC), Compress / decompress image data for effective use.
[0073]
The image data sent to the IMAC is stored in the MEM or HDD after data compression, and the stored image data is read out as necessary. The read image data is decompressed, returned to the original image data, and returned from the IMAC to the CDIC via the parallel bus Pb. After transfer from the CDIC to the IPP, the image quality processing is performed and the image is output to the writing I / F 134, and a reproduced image is formed on the transfer paper (paper) in the image forming unit 135.
[0074]
In the flow of image data, the functions of the digital multi-function peripheral are realized by the bus control by the parallel bus Pb and the CDIC. Facsimile transmission is performed by performing image processing on the image data read by the scanner 210 and the ADF 230 with the IPP and transferring the image data to the FCU via the CDIC and the parallel bus Pb. The FCU performs data conversion to the communication network and transmits it as facsimile data to the public line PN. Facsimile reception is performed by converting line data from the public line PN into image data by the FCU and transferring it to the IPP via the parallel bus Pb and CDIC. In this case, no special image quality processing is performed, and the image is output from the writing I / F 134 and a reproduced image is formed on the transfer paper in the image forming unit 135.
[0075]
In a situation where a plurality of jobs, for example, a copy function, a facsimile transmission / reception function, and a printer output function operate in parallel, the usage rights of the reading unit 211, the image forming unit 135, and the parallel bus Pb are allocated to the system controller 31a and the process. Control is performed by the controller 131. The process controller 131 controls the flow of image data, and the system controller 31a controls the entire system and manages the activation of each resource. The function selection of the digital multi-function peripheral is performed on the operation board 220, and processing contents such as an image reading function, an image data registration function, a copy function, a print function, a facsimile function, and a connection transfer function are selected by the selection input of the operation board 220. Set.
[0076]
The system controller 31a and the process controller 131 communicate with each other via the parallel bus Pb, CDIC, and serial bus Sb. Specifically, communication between the system controller 31a and the process controller 131 is performed by performing data format conversion for data and interface between the parallel bus Pb and the serial bus Sb in the CDIC.
[0077]
Various bus interfaces such as a parallel bus I / F 37, a serial bus I / F 39, a local bus I / F 33AA, and a network I / F 38 are connected to the IMAC. The system controller 31a is connected to related units via a plurality of types of buses in order to maintain independence in the entire ACP.
[0078]
The system controller 31a controls other functional units via the parallel bus Pb. The parallel bus Pb is used for transferring image data. The system controller 31a issues to the IMAC an operation control command for storing image data in the MEM and HDD. This operation control command is sent via IMAC, parallel bus I / F 37, and parallel bus Pb.
[0079]
In response to this operation control command, the image data is sent from the CDIC to the IMAC via the parallel bus Pb and the parallel bus I / F 37. The image data is stored in the MEM or HDD under the control of the IMAC.
[0080]
On the other hand, the ACP system controller 31a functions as a printer controller, network control, and serial bus control in the case of a call from the PC as a printer function. In the case of via the network, the IMAC receives print output request data via the network I / F 38.
[0081]
In the case of a general-purpose serial bus connection, the IMAC receives print output request data via the serial bus I / F 39. The general-purpose serial bus I / F 39 corresponds to a plurality of types of standards.
[0082]
Print output request data from the PC is developed into image data by the system controller 31a. The development destination is an area in MEM. Font data necessary for expansion is obtained by referring to the font ROM 36a via the local bus I / F 33a and the local bus Rb. The local bus Rb connects the controller 31a to the nonvolatile memory 35a and the RAM 34a.
[0083]
Regarding the serial bus Sb, in addition to the external serial port 32a for connection with the PC, there is also an interface for transfer with the operation board 220 which is an operation unit of the ACP. This is not print development data, but communicates with the system controller 31a via the IMAC, accepts processing procedures, displays the system status, and the like.
[0084]
Data transmission / reception between the system controller 31a and the MEM, HDD, and various buses is performed via the IMAC. Jobs that use MEM and HDD are centrally managed in the entire ACP.
[0085]
FIG. 5 shows an outline of the functional configuration of the CDIC. The image data input / output control 161 receives the image data output from the color document scanner 210 (SBU) and outputs it to the IPP. The IPP performs “scanner image processing” 190 (FIG. 7) and sends it to the image data input control 162 of the CDIC. The data received by the image data input control 162 is subjected to primary compression of the image data in the data compression unit 163 in order to increase the transfer efficiency on the parallel bus Pb. The compressed image data is converted into parallel data by the data converter 164 and sent to the parallel bus Pb via the parallel data I / F 165. Image data input from the parallel data bus Pb via the parallel data I / F 165 is serially converted by the data converter 164. This data is primarily compressed for bus transfer and is decompressed by the data decompression unit 166. The expanded image data is transferred to the IPP by the image data output control 167. In IPP, RGB image data is converted into YMCK image data by “image quality processing” 300 (FIG. 7), converted into image data Yp, Mp, Cp, Kp for image output of the printer 100 and output to the color printer 100. .
[0086]
The CDIC has a conversion function of parallel data transferred by the parallel bus Pb and serial data transferred by the serial bus Sb. The system controller 31a transfers data to the parallel bus Pb, and the process controller 131 transfers data to the serial bus Sb. For communication between the two controllers 31a and 131, the data converter 164 and the serial data I / F 169 perform parallel / serial data conversion. The serial data I / F 168 is for IPP, and serial data transfer is performed with IPP.
[0087]
FIG. 6 shows an outline of the configuration of the IMAC. The IMAC includes an access control 172, a memory control 173, a secondary compression / decompression module 176, an image editing module 177, a system I / F 179, a local bus control 180, a parallel bus control 171, a serial port control 175, a serial port 174, and a network. A control 178 is provided. The secondary compression / decompression module 176, the image editing module 177, the parallel bus control 171, the serial port control 175, and the network control 178 are each connected to the access control 172 via a DMAC (direct memory access control).
[0088]
The system I / F 179 transmits / receives commands or data to / from the system controller 31a. Basically, the system controller 31a controls the entire ACP. The system controller 31a manages the resource allocation of the MEM and HDD, and controls other units through the system I / F 179, the parallel bus control 171 and the parallel bus Pb.
[0089]
Each unit of ACP is basically connected to the parallel bus Pb. Therefore, the parallel bus control 171 manages the transmission / reception of data to / from the system controller 31a, the MEM, and the HDD by controlling the bus occupation.
[0090]
The network control 178 controls connection with the LAN. The network control 178 manages transmission / reception of data to / from an external expansion device connected to the network. Here, the system controller 31a is not involved in the operation management of the connected devices on the network, but controls the interface in the IMAC.
[0091]
The serial port 174 connected to the serial bus has a plurality of ports. The serial port control 175 includes a number of port control mechanisms corresponding to the types of buses prepared. Separately from the external serial port, it controls the command reception with the operation unit or the transmission / reception of data related to display.
[0092]
The local bus control 180 interfaces with a local serial bus Rb to which a RAM 34a necessary for starting the system controller 31a, a nonvolatile memory 35a, and a font ROM 36a for expanding printer code data are connected.
[0093]
In the operation control, command control is performed by the system controller 31a from the system I / F 179. Data control manages MEM and HDD access from external units, with MEM and HDD as the center. Image data is transferred from the CDIC to the IMAC via the parallel bus Pb. Then, the image data is taken into the IMAC by the parallel bus control 171.
[0094]
Memory access of the captured image data leaves the management of the system controller 31a. That is, the memory access is performed by direct memory access control (DMAC) independently of the system control. For access to the MEM and HDD, the access control 172 arbitrates access requests from a plurality of units. The memory control 173 controls the access operation of the MEM and HDD or the data read / write.
[0095]
When accessing the MEM and HDD from the network, data taken into the IMAC from the network via the network control 178 is transferred to the MEM and HDD by the direct memory access control DMAC. The access control 172 arbitrates access to the MEM and HDD in a plurality of jobs. The memory control 173 reads / writes data to / from the MEM and HDD.
[0096]
When accessing the MEM and HDD from the serial bus, the data taken into the IMAC via the serial port 174 by the serial port control 175 is transferred to the MEM and HDD by the direct memory access control DMAC. The access control 172 arbitrates access to the MEM and HDD in a plurality of jobs. The memory control 173 reads / writes data to / from the MEM and HDD.
[0097]
Print output data from a PC connected to the network or serial bus is developed by the system controller 31a in the memory area in the MEM and HDD using the font data on the local bus.
[0098]
The system controller 31a manages the interface with each external unit. For data transfer after being taken into the IMAC, each DMAC shown in FIG. 6 manages memory access. In this case, since each DMAC performs data transfer independently of each other, the access control 172 gives priority to job collisions or access requests regarding access to the MEM and HDD.
[0099]
Here, the access to the MEM and the HDD includes an access from the system controller 31a via the system I / F 179 for developing a bitmap of stored data in addition to the access by each DMAC. The DMAC data permitted to access the MEM and HDD in the access control 172 or the data from the system I / F 179 is directly transferred to the MEM and HDD by the memory control 173.
[0100]
The IMAC has a secondary compression / decompression module 176 and an image editing module 177 for data processing therein. The secondary compression / decompression module 176 compresses and decompresses data so that image data or code data can be effectively stored in the MEM and HDD. The secondary compression / decompression module 176 controls the interface with the MEM and HDD by DMAC.
[0101]
The image data once stored in the MEM and HDD is called from the MEM and HDD to the secondary compression / decompression module 176 via the memory control 173 and the access control 172 by the direct memory access control DMAC. The image data thus converted is returned to the MEM and HDD by the direct memory access control DMAC or output to the external bus.
[0102]
The image editing module 177 controls the MEM and HDD by the DMAC, and performs data processing in the MEM and HDD. Specifically, the image editing module 177 performs rotation processing of image data, synthesis of different images, and the like as data processing in addition to clearing the memory area. The image editing module 177 reads the secondary compressed data from the MEM and HDD, decompresses the secondary compressed data to the primary compressed data by the secondary compression / decompression module 176, and uses the same decoding logic as the CDIC data decompression 163 in the module 177. The next compressed data is decompressed into image data, expanded in the memory in the module 177, and processed. The processed image data is subjected to primary compression with the same encoding logic as the CDIC primary compression logic, and further subjected to secondary compression with the secondary compression / decompression module 176, and written to the MEM and HDD.
[0103]
FIG. 7 shows an outline of the image processing function of IPP. IPP is separated and generated (determination of whether an image is a character area or a photographic area: image area separation) 192, background removal 193, scanner gamma conversion 194, filter 195, color correction 302, magnification change 303, image processing 304, printer gamma conversion 305 And gradation processing 606 is performed. IPP is a programmable arithmetic processing means for performing image processing. Image data input to the CDIC from the output I / F 12 of the scanner 210 is transferred to the IPP via the CDIC, and the signal deterioration accompanying the quantization to the optical system and the digital signal by the IPP (scanner signal deterioration). Is corrected and output (transmitted) to the CDIC again. In the IPP, “image quality processing” 300 is performed on the image data returned from the CDIC to the IPP. In “image quality processing” 300, RGB signals are converted into YMCK signals by color correction 302, and scaling processing such as scaling 303, image processing 304, printer gamma conversion 305, gradation conversion, dither processing, or error diffusion processing is performed. 306 etc. are performed.
[0104]
As shown in FIG. 8, in addition to the liquid crystal touch panel 79, the operation board 220 includes a numeric keypad 80a, a clear / stop key 80b, a start key 80c, an initial setting key 80d, a mode clear key 80e, and a test print key 80f. The test print key 80f is a key for printing only one copy regardless of the set number of print copies and confirming the print result. By pressing the initial setting key 80d, the initial state of the machine can be arbitrarily customized. The paper size stored in the machine can be set or the state set when the copy function reset key is pressed can be arbitrarily set. When the initial setting key 80d is operated, an “initial value setting” function for setting various initial values, an “ID setting” function, a “copyright registration / setting” function, an “usage record output” function, etc. A selection button to specify is displayed. Also, select applications that are preferentially selected when there is no operation for a certain period of time, set the transition time to low power according to the International Energy Star Plan, and set the transition time to auto-off / sleep mode. It is possible to set.
[0105]
On the liquid crystal touch panel 79, various function keys and a message indicating the state of the image forming apparatus are displayed. The LCD touch panel 79 includes a “copy” function, a “scanner” function, a “print” function, a “facsimile” function, a “store” function, an “edit” function, a “register” function, a “concatenate” function, and other functions. A function selection key 80g for displaying and executing is selected. An input / output screen determined for the function designated by the function selection key 80g is displayed. For example, when the “copy” function is designated, as shown in FIG. 8, the function keys 79a and 79b and the number of copies and the image forming apparatus A message indicating the status is displayed. When the operator touches a key displayed on the liquid crystal touch panel 79, the key indicating the selected function is inverted in gray. When the details of the function must be specified (for example, the type of page printing), the detailed function setting screen is displayed by touching the key. Thus, since the liquid crystal touch panel uses a dot display device, it is possible to graphically perform an optimal display at that time.
[0106]
FIG. 9 shows a configuration of an electric system for image reading of the scanner 10 and the ADF 230. The electrical signals output from the image sensor 207, that is, R, G, B color analog image signals are respectively amplified by the signal processing 208 and converted into digital image signals, that is, image data by the A / D conversion 209. This image data undergoes correction processing by the reading processing 213 and is output to the IPP. In the A / D conversion 209, the digitally converted image data is converted into one obtained by removing the portion corresponding to the black offset. In this case, the offset from the black side includes a difference between channels when the output from the image sensor 207 has a two-channel configuration for each of the R, G, and B color components. The main purpose of the arithmetic processing here is to remove error components between channels.
[0107]
The R, G, B color analog image signals output from the imaging device 408 are amplified by the signal processing 208a and converted into image data by the A / D conversion 209a. This image data undergoes a correction process by the reading process 213a and is output to the IPP.
[0108]
The scanner control circuit 206 controls the lamp control circuit 205, the timing control circuit 211, and the motor control unit 260 in accordance with instructions from the system controller 31a and the process controller 131. The lamp control circuit 205 controls on / off of the exposure lamps 232 (232a, 232b) in accordance with an instruction from the scanner control circuit 206, and the brightness (time) of the exposure lamp 232 to the illuminance (light quantity) indicated by the reading process 213. Series average value or smooth value). Reference numerals 232a and 232b may be collectively indicated by reference numeral 232.
[0109]
The motor control unit 260 controls the sub-scanning drive motor 238 and the ADF motor 224 in accordance with instructions from the scanner control circuit 206. These motors are all stepping motors, and rotary encoders (E) 221 and 225 are connected to the shaft of the drive system. The scanning position (y) and drive amount of the first carriage, and the front and rear end positions and feed amount of the ADF feed document are grasped by counting the electric pulses generated by the rotary encoders 221 and 225. The paper sensor 223 shown in FIG. 9 includes a sensor that detects whether a document is on the document tray 241 of the ADF 30, a paper jam detection sensor, and a document size detection sensor.
[0110]
The timing control circuit 211 generates various signals in accordance with instructions or control signals from the scanner control circuit 206, the system controller 31a, and the process controller 131. That is, when image reading is started, a transfer gate signal for transferring data for one line to the shift register and a shift clock pulse for outputting the data of the shift register bit by bit are given to the image sensor 207, and the system controller 31a. In response to this, a pixel synchronization clock pulse CLK, a line synchronization signal LSYNC, and a main scanning effective period signal LGATE are output. The pixel synchronization clock pulse CLK is substantially the same signal as the shift clock pulse given to the image sensor 207. The line synchronization signal LSYNC is a signal corresponding to the line synchronization signal MSYNC output from the beam sensor of the image forming unit 135 of the printer 100, but output is prohibited when the image is not read. The main scanning effective period signal LGATE becomes high level H at a timing at which the image signal output from the image sensor 207 can be considered valid.
[0111]
Upon receiving a reading start instruction from the process controller 131, the scanner control circuit 206 controls the timing control circuit 211 to start reading of the image sensor 207, turns on the exposure lamp 232, and sub-scanning drive motor 238 (manual feed mode). Alternatively, driving of the ADF motor (ADF mode) is started. Further, the sub-scanning effective period signal FGATE is set to a high level H (outside the document area). This signal FGATE is switched to L indicating the inside of the document area when the first carriage reaches the document start end position (position from the home position HP to a + b) in the manual feed mode, and in the ADF mode, the document (from the registration roller) The feed conveyance amount at the front end is the HP position (“feed amount Df from registration roller 243 to base sensor 249” − “HP to base sensor 249”, which is the document reading position in the sheet-through image reading mode using ADF 30. When the feed amount a ") is reached, it is switched to L indicating the document area. When the first carriage passes through the document tail edge in the manual feed mode and when the document tail edge passes HP in the ADF mode, the sub-scan effective period signal FGATE is returned to H indicating the outside of the document area.
[0112]
FIG. 10 shows the configuration of the scanner control circuit 206. The CPU 254 performs input / output control of the scanner control circuit 206 and drive control of the sub-scanning drive motor 238 and the ADF motor. That is, in response to a command such as a test command or a document reading command from the system controller 31a or the process controller 131, carriage driving or ADF driving and image reading are performed. In the ROM 255, a control program for the scanner control circuit 206 is written. A RAM 256 is a working memory used by the CPU 254.
[0113]
FIG. 11 shows a functional configuration of the reading processes 213 and 213a shown in FIG. The A / D converters 209 and 209a convert the image reading signal into an 8-bit digital signal and output it to the reading processes 213 and 213a.
[0114]
In the reading process 213, the shading correction 216 performs shading correction for each scanning line, and corrects variations due to illumination unevenness and sensitivity unevenness for each pixel of the CCD. The image reading signal from the CCD 207 is due to uneven sensitivity at each pixel of the CCD and illuminance distortion due to the highest amount of light from the illumination lamp at the center of the scanning line. Despite variations and distortions. In order to correct this distortion, the reference white plate 239 that becomes uniform white is read, and the obtained image data is stored in the volatile memory 215 as “white reference plane data”. That is, the white reference plane data indicating the degree of “variation / distortion” in the main scanning direction is taken into the volatile memory 215. The shading correction 216 reads “white reference plane data” corresponding to each pixel from the original image data read by the CCD 207 from the volatile memory 215, and based on this, reads “variation, distortion” of the original image data. "Is corrected and output to the scaling process 219 in the next stage.
[0115]
The shading correction 216 includes a shading correction ROM, which includes a white reference for each of combinations of values 0 to 255 that can be taken by “white reference plane data” and values 0 to 255 that can be taken by image data of a document. Original image data that should be obtained when the plane data is assumed to be uniform is written. An image obtained by correcting the reading distortion of the image data of the original by giving a combination of the image data of the original read by the CCD 207 and the white reference plane data (volatile memory 215) addressed to the pixel to the address of the shading correction ROM. The data is output from the shading correction ROM and given to the “magnification process” 219 through the selector 218.
[0116]
Next, the scaling process 219 performs enlargement / reduction processing according to the scaling ratio designated by the user. In this embodiment, the main and sub independent scaling processes are performed. The reading density conversion in the main scanning direction is performed by a scaling process 219. Since the aperture (focusing rate) of the lens 236 and the number of reading pixels on the CCD 207 are fixed, the reading density in the main scanning direction is a constant value. In this embodiment, the reading density in the main scanning direction is set to 600 dpi. With respect to the read data at 600 dpi, the scaling process 219 performs density conversion to an arbitrary dpi by performing a thinning process using a line memory (not shown) or an interpolation process such as double writing. For example, in order to reduce (50%) to 300 dpi, two adjacent pixels of 600 dpi read data are thinned while being converted to their average value (1 pixel), and converted from 2 pixels to 1 pixel. Further, in order to enlarge (200%) to 1200 dpi, one pixel is written twice (2 pixels) and converted to 2 pixels by interpolation processing.
[0117]
The reading density conversion in the sub-scanning direction is performed by mechanical scaling. Stepping motors are used for the traveling body motor 238 and the transport motor 224, and the CPU 254 changes the driving speed of these motors, thereby changing the scanning speed of the document in the sub-scanning direction, that is, changing the reading density in the sub-scanning direction. To convert density. For example, to read at 300 dpi (50% reduction) with respect to a scanning speed of 600 dpi: V, to drive at a scanning speed of 2 × V and drive at 1200 dpi (200% enlargement) , Scanning speed: The motor is driven to scan at V / 2.
[0118]
In order to detect dust and dirt on the optical path from the surface of the reference white plate 239 (white reference surface) to the CCD 207, a non-volatile memory 214 and a difference calculation 217 are provided, and conveyance in front of the glass 240 as an image reading window is provided. In order to detect dust and dirt on the optical path from the white surface of the drum 244 to the CCD 207 through the glass 240, a non-volatile memory 255 and a difference operation 256 are provided. In order to detect reading density abnormal pixels due to dust and dirt on the optical path from the white surface of the transport drum 244 to the glass 240 to the CCD 207 immediately before reading each original, an addition 252, a volatile memory 253, and an abnormal pixel are detected. A detection 254 is provided.
[0119]
In both of the image reading by the optical system scanning for reading the document placed on the contact glass 231 and the surface sheet through image reading for reading the surface of the document conveyed by the conveying drum 244 through the glass 240. The image (white) of the reference white plate 239 is read immediately before image reading of each document, and image data (white reference plane data) is written in the volatile memory 215. For reference, FIG. 16 shows an outline of “white reference plane data”. In the case of front side sheet-through image reading, detection of a reading density abnormal pixel is performed when reading an image (white) on the reference white plate 239. The contents will be described later.
[0120]
When reading of the document is started, the read image data and the white reference plane data of the volatile memory 215 at the pixel position are given to the shading correction 216, and the image data corresponding to both image data is read from the shading ROM, and the selector 218 is read. The image data is output to the scaling process 219, and is subjected to the scaling process at the specified magnification and then output to the image data processing apparatus ACP (FIG. 4). The difference calculations 217 and 256 will be described later.
[0121]
In the reading process 213a, the shading correction 216a performs shading correction for each scanning line, and corrects variations caused by uneven illumination of the imaging device 408, uneven sensitivity for each pixel of the CCD, and the like. The shading correction 216a has the same function as 216 described above. However, the imaging device 408 reads the front surface (white reference surface) of the white back plate 409 facing it, and the white reference surface data stored in the nonvolatile memory 255a and the imaging device 408 read the back side of the document by back sheet through scanning. Image data is provided to the shading correction 216a. The scaling process 219a has the same function as 219 described above. In order to detect dust and dirt on the optical path from the surface of the white back plate 409 to the image pickup device (CCD) 207 of the image pickup device 408, a difference calculation 256a is provided. This difference calculation 256a includes a non-volatile memory 255a. The stored white reference plane data and image data obtained by reading the surface of the white back plate 409 by the imaging device 408 are given. In order to detect reading density abnormal pixels due to generation of dust and dirt in the optical path from the white surface of the white back plate 409 to the image pickup device inside the image pickup device 408 immediately before reading each document by backside sheet through reading, An adder 252a, a volatile memory 253a, and an abnormal pixel detection 254a are provided.
[0122]
When reading of the back side of the document is started by back side sheet through reading, the read image data and the white reference plane data of the volatile memory 255a at the pixel position are given to the shading correction 216a, and both image data are read from the internal shading ROM. Corresponding image data is read out and output to the scaling process 219a through the selector 218a. After the scaling process at the specified magnification is performed, the image data is output to the image data processing apparatus ACP (FIG. 4). The difference calculation 256a and detection of an abnormal reading density pixel will be described later.
[0123]
FIG. 12 shows an outline of document reading control in response to an image reading start signal (start instruction) given by the system controller 31a by the CPU 254 of the scanner control circuit 206. When the image reading start is input from the operation board 20 or the personal computer PC, the system controller 31a gives an image reading start signal to the CPU 254 in response thereto.
[0124]
In response to the image reading start signal, the CPU 254 starts the forward scanning drive of the first and second carriages from the home position HP (step 1), and at the timing when the reference white plate 239 enters the reading field of the first mirror 233. The shading gate signal applied to the reading process 213 is switched from “H” to “L”, and the correction gate signal is switched from “H” to “L” at the timing when the reading visual field advances around the center of the reference white plate 239. Is “L”, “white reference plane data update 1” is performed by the reading process 213 (step 2). In the following, the word “step” is omitted, and only the step number is written in parentheses. In “update of white reference plane data 1”, the image data of the surface of the reference white plate 239 is read, and the read image data for one line is updated and written in the volatile memory 215 as white reference plane data.
[0125]
When the white reference plane data update 1 is completed, the CPU 254 returns the shading gate signal and the correction gate signal to “H”. Then, referring to the detection signal of the sensor for detecting the presence or absence of the document on the document tray 241 of the ADF 30, when the document is not present, the forward scanning is continued to read the document image on the contact glass 231 and the read image. Data shading correction 216 is performed (4). When the tail end of the document on the contact glass 231 is passed, the forward scanning drive of the carriage is stopped, followed by reverse and reverse scanning (return) driving, positioning the first carriage at HP and finishing the carriage driving. (5). Then, the document reading count value Nsa of the register Nsa (one area of the memory) of the nonvolatile memory 257 is incremented by 1 (6).
[0126]
If the detection signal of the sensor for detecting the presence or absence of the document on the document tray 241 of the ADF 30 is that there is a document, the forward drive of the carriage is stopped and returned to HP. That is, the first carriage (first mirror 233) is positioned at the image reading position (glass 240) of the front sheet through (7). Proceeding to “Sheet-through reading of front surface” (8), image reading of the back plate (white surface of the transport drum 244) for the number of main scanning lines is performed, shading correction is performed, and image data at the same pixel position is added. In the volatile memory 253 (9, 10), the abnormal pixel detection 254 calculates the line average value of the integrated image data for one line on the volatile memory 253 (11). Then, pixels having a density level equal to or lower than the threshold value Th1 in which the accumulated image data in pixel units is a predetermined ratio lower than the average value are extracted as abnormal pixel candidates. Next, paying attention to the number of images of the continuous distribution of the abnormal pixel candidates in the main scanning direction, the abnormal pixels are determined. An abnormal pixel candidate group continuously distributed over a predetermined threshold Th2 for detecting the size of the abnormal pixel candidate group is determined as an abnormal pixel due to contamination (11). When an abnormal pixel is detected, a dirt warning is displayed on the liquid crystal touch panel 79 of the operation board 220 (13, 14). If the image reading by the ADF 30 feeding is started in response to the image reading command from the personal computer PC, this dirt warning is transmitted to the PC and displayed on the display connected to the PC. When no abnormal pixel is detected, the dirt warning display is deleted (14).
[0127]
Regardless of whether or not an abnormal pixel is detected, the ADF 30 reads the surface image of the document that is sent to the reading glass 240 and transported, and performs shading correction (15). When the image reading of one document is finished, the document reading count value Nsa of the register Nsa is incremented by 1 (17), and the detection signal of the sensor for detecting the presence or absence of the document on the document tray 241 of the ADF 30 is referred again ( 18) If there is a document, “surface sheet through reading” (8) is subsequently performed. Until there are no more documents on the document tray 241 of the ADF 30, “sheet through reading on the front surface” (8) is performed for each document. When the “sheet-through reading of the front surface” (8) of the last document in the ADF 30 is completed, the CPU 254 ends the document image reading control.
[0128]
When the image reading command is double-sided (front and back) reading, for each original, the process proceeds to “front-side sheet-through reading” (8), and at the timing when the original advances from the reading glass 240 to the imaging device 408, Sheet-through reading "(16). This content is the same as the content of “surface sheet through reading” (8) described above. The image data processing of “front side sheet through reading” (8) is performed by reading processing 213, and the image data processing of “back side sheet through reading” (16) is performed by reading processing 213a.
[0129]
As described above, every time one original is read, the original reading count value Nsa of the register Nsa is incremented by 1 (6, 17). When the reading of the designated document (s) by the scanner 210 and the ADF 230 is completed, the CPU 254 addresses the data Ra of the register Ra of the nonvolatile memory 257 in the number table (Table 1) of the nonvolatile memory 257. The threshold data Rsa is read (19). Next, it is checked whether the document reading frequency value Nsa is the read threshold value data Rsa (20). If so, “white reference plane data update 2” (21) is executed and the data in the register Ra is stored. Increment by one (22).
[0130]
In “White reference plane data update 2” (21), the CPU 254 reads out the white reference plane data in which each data is composed of 8 bits in the volatile memory 215, extracts the upper 7 bits of each data, that is, data The value is halved and updated and written to the nonvolatile memory 214. The reason why the data value is halved is to reduce the required memory capacity of the nonvolatile memory 214.
[0131]
Table 1 shows threshold value data of the number table. Initially, since there is a low probability of dust and dirt being attached, white reference plane data in the nonvolatile memory 214 is updated at intervals of small increments of the document reading count integrated value Nsa. When the integrated value Nsa increases, this interval is increased. It is getting bigger. Further, when the paper path is maintained, the white reference plane data update interval in the nonvolatile memory 214 returns to the initial state (43 in FIG. 14). This makes it possible to carry out a reading test (32 to 34 in FIG. 14) of the reference white plate 239 described later, taking into account the influence of deterioration of the document irradiation lamp over time, and the like. The stain on the white plate 239 can be confirmed (32 to 34 in FIG. 14).
[0132]
[Table 1]

[0133]
When the initial setting key 80d of the operation board 220 is pressed, the operation board 220 switches the display on the liquid crystal touch panel 79 to the initial setting menu screen shown in FIG. When the “scanner initial setting” button on this menu screen is clicked, the operation board 220 displays a scanner initial setting menu screen on the liquid crystal touch panel 79. The menu screen includes an item “white reference plane reading test”. When the user clicks this item, the system controller 31 a gives a “white reference plane reading test” command to the CPU 254. In response to this command, the CPU 254 executes a “white reference surface reading test”.
[0134]
FIG. 14 shows the content of the “white reference surface reading test”. When proceeding to this, the CPU 254 starts the forward scanning drive of the first and second carriages from the home position HP (step 1), and at the timing when the reference white plate 239 enters the reading field of the first mirror 233, the reading processing 213 is performed. The shading gate signal to be applied is switched from “H” to “L”, the correction gate signal is switched from “H” to “L” at the timing when the reading visual field advances around the center of the reference white plate 239, and both signals are “L”. In the meantime, the white reference plane data is updated 1 by the reading process 213 (31, 32). In “White reference surface data update 1” (32), the image data of the surface of the reference white plate 239 is read, and the read image data for one line is updated and written in the volatile memory 215 as white reference surface data. Then, the carriage is returned to HP (33). HP is a position at which surface sheet through reading can be performed through the glass 240 serving as a document reading window.
[0135]
Next, the CPU 251 performs a difference calculation in the reading process 213 (FIG. 11), and displays the difference value as an image density, that is, image data, on the liquid crystal touch panel 79 of the operation board 220 (34). At this time, the difference calculation 217 of the reading process 213 reads 7-bit white reference plane data from the non-volatile memory 214 and converts it into 8-bit data by digit shift in the upper digit direction, that is, white representing 2 times the read data value. Converting to reference plane data, the difference value of the white reference plane data updated and written in the volatile memory 215 with respect to the white reference plane data is calculated. The difference is calculated as follows:
Dkn: white reference plane data (8 bits) stored in the volatile memory 215,
n is 1-7200,
Dfn: white reference plane data (7 bits) stored in the non-volatile memory 214,
Sn: difference data,
Sn = | (Dfn × 2) −Dkn |.
[0136]
The difference value data Sn passes through the selector 218 and the scaling process 219 as normal document image data, is further processed by the ACP, is stored in the MEM, and is displayed on the liquid crystal touch panel 79 of the operation board 220 as an image. FIG. 19 shows a display example. The difference value data is repeatedly written and displayed over a plurality of lines in the block labeled “stain of the reference white plate” on the liquid crystal touch panel 79, but in FIG. 19, since the reference white plate 239 is not dirty, the image is Not appearing. When the user clicks the main scanning pixel position scroll arrow displayed on the liquid crystal touch panel 79 shown in FIG. 19, the display area on one line is changed, and the horizontal scanning main scanning pixel position number is switched accordingly. The
[0137]
Next, the CPU 254 performs surface sheet through reading through the glass 240, and updates and writes the read image data in the volatile memory 215 (35). Here, since the document is not fed, white reference plane data obtained by reading the white surface of the transport drum 244 is written in the volatile memory 215. On the other hand, in the non-volatile memory 255, the upper 7 bits (data representing 1/2 of the read data value) of the white reference plane data that has previously read the white surface of the transport drum 244 are accumulated as white reference plane data. Yes. Next, the CPU 251 reads the 7-bit white reference plane data from the non-volatile memory 255 using the difference calculation 256 of the reading process 213 and converts it into 8-bit data by the digit shift in the upper digit direction, that is, the read data value Conversion to white reference plane data representing twice, and a difference value of the white reference plane data updated and written in the volatile memory 215 with respect to the white reference plane data is calculated. The difference value data passes through the selector 218 and the scaling process 219 as normal document image data, is further processed by the ACP, stored in the MEM, and displayed as an image on the liquid crystal touch panel 79 of the operation board 220 (36). ). FIG. 19 shows a display example. The difference value data is repeatedly written and displayed over a plurality of lines in the block labeled “dirty surface reading” on the liquid crystal touch panel 79. FIG. 19 shows that there is dirt or dust on the optical path from the surface of the transport drum 244 to the CCD 207.
[0138]
Next, the CPU 254 reads the white back plate 409 by backside sheet-through reading by the imaging device 408, and updates and writes the read image data in the volatile memory 257 (37). On the other hand, in the non-volatile memory 2255a, the upper 7 bits (data representing 1/2 of the read data value) of the white reference plane data obtained by previously reading the white surface of the white back plate 409 are stored as white reference plane data. ing. Next, the CPU 251 reads the 7-bit white reference plane data from the non-volatile memory 255a using the difference calculation 256a of the reading process 213a and converts it into 8-bit data by digit shift in the upper digit direction, that is, the read data value Conversion to white reference plane data representing twice, and a difference value of the white reference plane data read into the volatile memory 257 with respect to the white reference plane data is calculated. The difference value data is subjected to selector 218a and scaling processing 219a as normal document image data, further subjected to image processing by ACP, accumulated in MEM, and displayed as an image on liquid crystal touch panel 79 of operation board 220 (38). ). FIG. 19 shows a display example. The difference value data is repeatedly written and displayed over a plurality of lines in a block labeled “dirt of back side reading” on the liquid crystal touch panel 79. FIG. 19 shows that there is no dirt or dust in the optical path from the surface of the white back plate 409 to the image pickup device inside the image pickup apparatus 408.
[0139]
Next, the CPU 254 responds to the click by the user of “print”, “update” or “end” displayed on the liquid crystal panel 79 of the operation board 220 from the system controller 31a, and “print”, “update” or “end”. (39, 41, 44). When “print” is clicked, the system controller 31a performs processing for print output on each differential data stored in the MEM, repeatedly outputs the same line information to the printer 100, and prints on one sheet of paper. Out (39, 40). In general, an image in which three display blocks on the liquid crystal touch panel 79 shown in FIG. 19 are expanded so as to represent the entire length of one line is printed on a sheet.
[0140]
When the “update” command arrives, the CPU 254 extracts the upper 7 bits of the white reference surface data (8 bits) of the white surface reading of the transport drum 244 by the front sheet through reading in the volatile memory 215, 2, the upper 7 bits of the white reference plane data (8 bits) of the white surface reading of the white back plate 409 by the back sheet through reading of the imaging device 408 in the volatile memory 257 are extracted and stored in the nonvolatile memory 2. Writing and scanning the carriage to scan the white surface of the reference white plate 239, return the write carriage to the nonvolatile memory 215 and return the carriage to HP, and then white reference surface data (8 of the white surface of the reference white plate 239 in the volatile memory 215) The upper 7 bits of the bit) are extracted and written into the nonvolatile memory 214 (41, 42). That is, the white reference plane data in the nonvolatile memories 214, 255, and 255a is updated. Then, the original reading integrated value Nsa of the register Nsa is initialized to 0 (43).
[0141]
When the “end” command arrives, the CPU 254 ends the “white reference surface reading test” (44).
[0142]
At the time of shipment from the factory, that is, when the reference white plate 239, the transfer drum 244, and the white back plate 409 are all new and shiny and there is no dirt or dust in any of the reading optical paths, the shipping test personnel By instructing “reading test of surface” and further instructing “update”, the non-volatile memories 214, 255, and 255 a have white reference surfaces obtained by reading the surfaces of the reference white plate 239, the transport drum 244, and the white back plate 409, respectively. Data is stored.
[0143]
When there is no dirt or dust on each reference surface and reading optical path, the white reference surface data is in a state as shown in FIG. 16, but when dirt or dust adheres, an abnormally low density peak is obtained as shown in FIG. And the difference calculation result is as shown in FIG. Referring to FIGS. 16 to 18, when there is no influence of dust or dirt, the image is white data, but when there is an influence of dirt or dirt, as shown in FIG. A black vertical streak appears at the position. As a result, the influence of dust and dirt can be clearly confirmed.
[0144]
For example, when an abnormal pixel is detected by the “sheet through reading of the front surface” (8) or “sheet through reading of the back surface” (16) shown in FIG. After performing the cleaning of the reading optical path, it is possible to confirm whether dust or dirt on the reference plane and the reading optical path have been successfully removed by inputting the above-described “white reference plane reading test”. If black vertical streaks are recognized even after cleaning, it can be determined that dust and the like are still outside the cleaned range, and further cleaning inside the apparatus is performed. If there is no black vertical streak for dust and dirt as a result of the “White Reference Plane Reading Test”, click “Update” to update the white reference plane data in the non-volatile memory to the latest reading data. be able to.
[0145]
FIG. 20 shows a first modification of the reading processes 213 and 213a. In this modification, the scaling process 218, 218a is arranged in front of the non-volatile memories 214, 255, 255a for storing the white reference plane data, and the white reference plane data is written to the non-volatile memories 214, 255, 255a. When the white reference plane data is read out from the non-volatile memories 214, 255, and 255a, the number of one line is reduced to half by thinning out every other pixel (50% reduction) by the scaling processing 218 and 218a. The read white reference plane data of one pixel by the scaling processing 218, 218a is expanded to two times by interpolation (200% expansion) for allocating to two pixels. Other functions are the same as those of the reading processes 213 and 213a shown in FIG.
[0146]
In the second modification of the reading processes 213 and 213a, as in the first modification, the number of one line of white reference plane data to be written in the nonvolatile memories 214, 255, and 255a is changed by the scaling processes 218 and 218a. The amount is reduced by half by thinning out every other pixel (reduction of 50%). The white reference plane data read from the nonvolatile memories 214, 255, and 255a is not expanded by the difference calculation 217, 256, and 256a, and is obtained by a new reading of the reference white plate 239, the transport drum 244, and the white back plate 409. The number of white reference plane data for one line is reduced by half by thinning out every other pixel (50% reduction) by scaling processing 218, 218a and used for the difference calculation. The difference calculation in this second modification is
Dkn: white reference surface data for reference surface reading, n is 1 to 3600,
Dfn: white reference plane data stored in the non-volatile memory,
Sn: difference data,
Sn = | Dfn−Dkn |
It becomes.
[0147]
Since the difference data Sn is transferred to the ACP as image data and displayed on the liquid crystal touch panel 79, the amount of data transferred to the liquid crystal touch panel 79 is halved. This makes it possible to reduce the size of the non-volatile memory while utilizing the scaling process that is originally provided.
[0148]
【The invention's effect】
If the white reference plane (239, 244, 409) is contaminated, the difference value between the contaminated parts is large and is output as a high-density image. By visually checking this output, it can be visually confirmed whether there is dust or dirt in the optical path from the white reference plane to the image sensor. As a result, it is possible to accurately grasp the state of the apparatus that causes an abnormal image due to dust or dirt, and the efficiency of confirmation work at the time of maintenance by a service person is improved.
[Brief description of the drawings]
FIG. 1 is an enlarged front view showing an appearance of a full-color copying machine having a composite image processing function according to an embodiment of the present invention.
FIG. 2 is an enlarged longitudinal sectional view of the color printer 100 shown in FIG.
3 is an enlarged vertical sectional view of the color scanner 210 and the ADF 230 shown in FIG.
4 is a block diagram showing a configuration of an image processing system in the copying machine shown in FIG. 1. FIG.
5 is a block diagram showing a configuration of an image data interface control CDIC shown in FIG. 4. FIG.
6 is a block diagram showing a configuration of an image memory access control IMAC shown in FIG. 4. FIG.
7 is a block diagram showing an image data processing function of the image data processor IPP shown in FIG. 4. FIG.
FIG. 8 is an enlarged plan view of a part of the operation board 220 shown in FIG. 1;
9 is a block diagram showing a configuration of an image reading electric circuit system of the document scanner 210 and the ADF 230 shown in FIG. 1. FIG.
10 is a block diagram showing a configuration of a scanner control circuit 206 and a motor control unit 260 shown in FIG.
11 is a block diagram illustrating a functional configuration of reading processing 213 and 213a illustrated in FIG. 9;
12 is a flowchart showing an outline of image reading control of a CPU 254 shown in FIG.
13 is a plan view showing a menu screen displayed on the liquid crystal touch panel 79 by the operation board 220 when the initial setting key 80d shown in FIG. 8 is operated. FIG.
14 is clicked when “scanner initial setting” shown in FIG. 13 is clicked, and in response to this, “white reference plane reading test” on the menu screen displayed on the liquid crystal touch panel 79 by the scanning board 220 is clicked. 11 is a flowchart showing the content of a “white reference surface reading test” executed in cooperation by the system controller 31a shown in FIG. 4 and a CPU 254 shown in FIG.
15 is a time chart showing a level change of a timing signal generated during image reading scanning of a document on a contact glass 231 of the scanner 10 shown in FIG.
16 is a graph showing an outline of the distribution of white reference plane data for one line, which is read data of the reference white plate 239, the transport drum 244, and the white back plate 409. FIG.
FIG. 17 is a graph showing an outline of the distribution of white reference plane data for one line when there is dirt or dust on the reading surface or the reading optical path.
18 is a graph showing a distribution on one line of a difference value of the currently read white reference plane data shown in FIG. 17 with respect to the reference white reference plane data shown in FIG. 16;
19 is a plan view showing an image display of difference data displayed on the liquid crystal touch panel 79 shown in FIG. 8. FIG.
20 is a block diagram illustrating a first modification of reading processing 213 and 213a shown in FIG. 9. FIG.
[Explanation of symbols]
1: Photoconductor 2: Charging device
3: Developing device 4: Cleaning device
5: Static elimination device 6: Exposure device
7: First transfer belt
8-10: Roller
11: First transfer means
12: Cleaning device
13: Second transfer belt
14-16: Rotating roller
17: Second transfer means
18: Cleaning device
19: Charger
20: Paper (recording medium)
21, 22: Paper cassette
23: Fixing device 24: Paper discharge guide
25: Paper discharge roller
26: Output stack
27: Supply toner storage unit
28: Cartridge
29: Frame 30: Opening and closing spindle
31, 32: Paper feed roller
33: Registration roller
221 and 225: Rotary encoder
224: Stepping motor
231: Platen glass 232: Illumination lamp
233: First mirror 234: Second mirror
235: Third mirror 236: Lens
207: Image sensor 238: Stepping motor
239: Reference white plate 240: Glass
241: Document tray 242: Pickup roller
243: Registration roller pair 244: Conveying drum
245: Pressing roller 246, 247: Paper discharge roller
248: Pressure plate also serving as a discharge tray
249: Base point sensor 250: Axis
251: Scale 260: Motor control unit
408: Imaging device 409: White backboard

Claims (6)

An image pickup apparatus that reads an image of a document and generates an image signal, means for converting the image signal into digital data, that is, image data, memory means for storing white reference plane data obtained by reading the white reference plane by the image pickup apparatus, and In a document reading apparatus comprising: image data obtained by reading an original by an imaging device; and means for correcting shading using white reference plane data of the memory means.
Non-volatile memory for storing white reference plane data;
Means for calculating a difference of white reference plane data obtained by reading the white reference plane by the imaging device with respect to white reference plane data of the nonvolatile memory; and
Means for outputting the difference as image data;
An original reading apparatus comprising: Input means for instructing a white reference plane reading test; and
A reading test control means for reading a white reference plane by the imaging device in response to an instruction of the white reference plane reading test and outputting the image by the output means using the difference calculated by the difference calculating means as image data; The document reading device according to claim 1, further comprising: A contact glass for placing a document; an image pickup device for reading an image of a document placed and fixed on the contact glass by mechanical scanning of an optical system or an image sensor parallel to the contact glass; The document reading device according to claim 1, further comprising: a white reference surface that is arranged outside and can be read by the imaging device. A document reading window; a document transfer means for sending a document to the document reading window and passing the document reading window across the document reading window; 4. The document reading device according to claim 1, further comprising: a white reference surface disposed outside a window and capable of being read by the imaging device. Document transport means for feeding a document on a paper feed tray and transporting it to a paper discharge tray; an imaging device for reading an image of the transported document and generating an image signal; and a back portion of the document transported facing the imaging device 4. The document reading device according to claim 1, further comprising a white reference surface positioned at a position of the document reading device. 6. The document reading device according to claim 1, wherein the image data processing device that converts shading-corrected image data output from the document reading device into image data for printing; and the printing device An image forming apparatus comprising: a printing unit that forms an image represented by the image data on a sheet.

Images