JP3870133B2 - Ink jet recording apparatus and ink jet recording method - Google Patents

Description

の演算によって求めることができ、 同様にしてドットｄ（ｍ＋１）のｍマトリックスラインへの影響度Ｚ_{m ＋１}（Ｌ）を求めることができる。
なお、前記中心角θは、ドットとｍマトリックスラインとの２個の交点と、ドットの中心とを結んだ２本の線分（半径）のなす角度である。
【００５８】
また、ｄ（ｍ）のｍマトリックスラインへの影響度Ｚ_ｍ（Ｌ）は下式により求めることができる。
Ｚ_m（Ｌ）＝１００−Ｚ_m（Ｌ−１）−Ｚ_m（Ｌ＋１）（％）
【００５９】
ここで、ドットの半径Ｒの値が各ノズルによって異なる場合には、それぞれ個別の値を代入することで算出できる。
また、ドットの形状が真円でない場合にも演算は複雑になるが同様に求めることができる。その場合は複雑なドット形状を、演算の容易な所定の形状に近似させても良い。
【００６０】
このようにしてあるマトリックスライン（Ｌ）の記録状態、特に濃度に影響を与えるノズルを解析することで、そのライン（Ｌ）の濃度を予測することができる。
すなわち、理想とする記録ドットによる濃度をＤ_ｉとしラインＬ番目の予測する濃度をＤ_Ｌとすると、
予測する濃度Ｄ_Ｌは、近傍のノズルから吐出されて記録ラインＬにかかるｍ−ａからｍ＋ｂ（ａ、ｂは正の整数）番目のノズルからの影響度Ｚ（Ｌ）を統合した下式で表される。すなわち、
Ｄ_Ｌ＝ｋ_ｄｅｎ（Ｚ_ｍ−ａ（Ｌ）…Ｚ_ｍ−１（Ｌ）＋Ｚ_ｍ（Ｌ）＋Ｚ_ｍ＋１（Ｌ）…Ｚ_ｍ＋ｂ（Ｌ））
【００６１】
ここで、ｋ_ｄｅｎは、ドットの面積から実濃度を求める係数であり、記録物の濃度等を測定して求めることができる。
そして、ヘッド補正に用いる係数Ｈ_ｃｏｎｆは、
Ｈ_ｃｏｎｆ（Ｌ）＝ｋ_ｈｅａｄ×Ｄ_Ｌ／Ｄ_ｉ
として与えられ、記録マトリックスの実際上の記録媒体上の濃度への寄与の状態を知ることができる。
【００６２】
ここで、ｋ_ｈｅａｄは係数Ｋを微調整する係数であり、記録媒体や記録の環境などにより変化し、実験的に求めることができる。
このＨ_ｃｏｎｆを用いて記録する画像を補正したり、各ノズルの吐出にかかわる駆動信号等を制御して吐出量を変更したりすることでヘッドシェーディングを実施する。
【００６３】
このように、上記実施形態においては、各ラインの記録に際して、そのマトリックスラインにかかるように着弾して形成されるドットによって、濃度的な影響を受ける場合にも、その影響を勘案して記録補正を行うようになっているため、インク滴にＹ方向への着弾誤差が生じるようなノズルを有する記録ヘッドにあっても、良好な補正効果を得ることができ、高品位な画像を形成することができる。
【００６４】
また、上記実施形態では、各マトリックスラインＬ毎に対応するノズルの補正係数を算出するようにしたが、一つのマトリックスラインに関して求めた隣接するマトリックスラインからの影響度…Ｚ_ｍ−１（Ｌ）、Ｚ_ｍ（Ｌ）、Ｚ_ｍ＋１（Ｌ）…を用いて、そのマトリックスラインに隣接するマトリックスラインＬ−１を記録するｍ−１番目のノズルに対する補正係数を求めるようにしても良い。具体的には、ヘッド補正に用いる係数Ｈ_ｎｏｚｚを以下のようにして算出する。 すなわち、ラインＬの処理により、本来、ラインＬ−１に対して記録を行うべきｍ−１番目のノズルに対してもヘッド補正を行うこととし、ラインＬの濃度に影響するノズルおよび／またはそのノズルで記録する画像に対しても補正を行う。
【００６５】
ノズルｍによるインクドットに対して影響するインクドットのノズルがＬ−１、Ｌ、Ｌ＋１であった場合には、ヘッド補正に用いる計数Ｈ_ｎｏｚｚは以下のようにして求める。
Ｈ_ｎｏｚｚ（Ｌ）＝Ｚ_ｍ（Ｌ−１）×Ｈ_ｃｏｎｆ（Ｌ−１）＋Ｚ_ｍ（Ｌ）×Ｈ_ｃｏｎｆ（Ｌ）＋Ｚ_ｍ（Ｌ＋１）×Ｈ_ｃｏｎｆ（Ｌ＋１）
また上式では省略したがそれぞれの項に必要に応じて係数を設けても良い。
すなわち、Ｌマトリックスラインを記録するｍ番目のノズルに対する補正係数は、ｍ番目のノズルから吐出されたインク滴によって形成されたインクドットが影響を及ぼしたマトリックスライン（上式ではＬ−１、Ｌ＋１）の予測される記録濃度と理想とする記録濃度の補正についても考慮することになる。
【００６６】
言い換えれば、ｍ番目のノズルから吐出したインクドットが、Ｌ−１マトリックスラインに対する影響度と、Ｌマトリックスライン、Ｌ＋１マトリックスラインに対する影響度とから、Ｌ−１マトリックスライン、Ｌ＋１マトリックスラインの状況に応じて、ヘッド補正データを算出することになる。
上記の方法によれば、例えば着目するマトリックスラインの隣のマトリックスライン側にインクドットが大きくずれて形成されてしまっている場合にも、そのマトリックスラインに影響を与えたノズルに対する画像データの補正および／またはノズルの吐出量の補正によりマトリックスラインの補正を実現することができ、より優れた補正機能を得ることができる。
【００６７】
なお、本発明は、１パス記録動作には特に有効なものとなっているが、記録ヘッドの異なるノズル群によって複数回走査することによって同一の記録領域の画像を完成させるようにしたいわゆるマルチパス方式の記録においても本発明は有効である。マルチパス方式の記録においては、不良ノズルを検知した後、異なる記録走査時にその不良ノズルによって記録された領域を、他のノズル群によって記録するため、一つの不良ノズルによる画像品質の低下を軽減することができるが、さらに本発明は実質的に同一の記録走査において、簡易な処理方法で不良ノズルによる画質劣化を防止できるため、マルチパス記録方式の優位性と相俟ってより高品位な画像を形成することが可能となる。
【００６８】
［第２，３，４の実施形態］
上記第１の実施形態においては、ノズルプロファイル情報を設定する上での重要なパラメータとしてインクドットのＹよれ値を用いたが、本発明はＹよれ値だけでなく、その他の値をパラメータとして用いることも可能である。
【００６９】
例えば、図１２に示す本発明の第２の実施形態にあっては、ステップＳ１３に示すように、前記パラメータとして不良ノズルのＹよれ値１３だけでなく、ドット径を用いており、また、図１３に示す本発明の第３の実施形態においては、ステップＳ２３に示すように、Ｙよれ値、ドット径に加えてＸよれ値を用いており、さらに、図１４に示す本発明の第４の実施形態においては、ステップＳ３３に示すように、Ｙよれ値、ドット径、Ｘよれ値の他に、ドット形状をパラメータとして用いている。
【００７０】
これら第２〜第４の実施形態のように、パラメータをより多く設定するようにした結果、ノズルプロファイル情報としてより精密な情報を得ることができるようになり、前記第１の実施形態に比べ、より階調性に優れ、かつ、すじむらによる影響の少ない画像を得ることが可能となった。なお、図１２ないし図１４において、前述のステップＳ１３，Ｓ２３，Ｓ３３以外のステップは、前記第１の実施形態において説明した各ステップＳ１，Ｓ２及びＳ４〜Ｓ６と略同様である。
【００７１】
また、本発明は、色毎に複数の濃淡インク、大小ドットを使用するインクジェット記録装置に対しても何等支障なく適用可能であり、その場合においても、より高次の画質を記録媒体上に再現することができる。
【００７２】
また、本発明は、図２に示したように、複数のノズルを記録方向に概略垂直に配列してなるノズル群を有し、同一走査で記録することのできる隣接ノズルとの間隔が、記録する画像の各画素に対応した間隔で略配列されているインクジェット記録ヘッドを備えたインクジェット記録装置、すなわち、１回の走査で画像記録が完了するようなフルライン型のインクジェット記録装置には特に有効である。このフルライン型のインクジェット記録装置では、基本的にマルチパス方式のプリンタに比より簡略な構成で記録装置を構成することができると共に、記録速度が格段に速いという利点があり、本発明を適用することによって、画像品質における改善が図られることにより、コスト、記録速度、画質のいずれの面においても優れたインクジェット記録装置の実現が可能となる。
【００７３】
ここで、隣接するノズルの間隔が記録マトリックスの隣接するラインの間隔よりも離れている場合、すなわち、記録ヘッドの解像度が記録マトリックスの解像度より低い場合には、画像の記録はマルチパス方式にて行なったり、同色のインク滴を吐出する他の解像度の高い記録ヘッドを用いて行うこととなる。この場合、解像度の異なる他の記録ヘッドを用いたとしても、記録マトリックスに実質的に同一走査で記録することと同様に記録できるので、本発明は好適に適応できる。またマルチパスでの記録でも、実現することは可能である。しかしながら、近接するノズルは実質的にも近接している方が、前述のように、単純な構成でインクジェットプリンタを構成することができるほか、高速な記録が可能であるので、フルマルチ型プリンタの好適に用いられる。
【００７４】
画像を記録する目的にもよるが、隣接するノズルの解像度は、次のような値であることが望ましい。例えば、インクジェット記録によって、ポケット写真のように小さいサイズの画像を高画質に記録する必要がある場合には、隣接するノズルの間隔は、インク滴の吐出量が４０ｐｌ±１０程度であれば、３００ｄｐｉ（１００μｍ）程度に設定することが好ましく、さらに、吐出量が１０ｐｌ±５程度であれば６００ｄｐｉ（４０μｍ）程度に近接していることが好ましく、さらに好ましくは吐出量が５ｐｌ±２程度であれば１２００ｄｐｉ（２０μｍ）、吐出量２ｐｌ±１程度であれば２４００ｄｐｉ（１０μｍ）とすることが望ましい。また、ポケット写真のように、近接した状態で画像を観る場合とは異なり、遠くから画像を視認する場合には、大きなサイズの記録物を得るならば、より吐出量の大きいノズルを、比較的大きなノズル間隔のノズル列で記録することになるが、その場合にも本発明は好適である。
【００７５】
また、本発明は、電気熱変換体などから発する熱エネルギーによってインクを吐出させるようにした記録ヘッドを用いる記録装置に限らず、ピエゾなどの圧電素子を用いてインクを吐出させるようにした記録ヘッドを用いる記録装置にも適用可能であり、本発明は、インクをノズルより吐出するインクジェット記録装置であれば、いかなるものにも適用可能である。
【００７６】
【実施例】
以下、本発明の実施例を説明する。
〈実施例１〉
上述した本発明の第１の実施形態に示すインクジェット記録装置および記録方法により記録を行った実施例を説明する。記録ヘッドは、１２００ｄｐｉの解像度を有し、ノズルが４０９６ノズル配列されたものとし、１回のインク吐出量（インク滴の量）は４．５±０．５ｐｌに設定した。
【００７７】
色材を含有するインクの組成は以下の通りである。
（処方Ｙインク）
・グリセリン ５．０重量部
・チオジグリコール ５．０重量部
・尿素 ５．０重量部
・イソプロピルアルコール ４．０重量部
・染料Ｃ．Ｉ．ダイレクトイエロー１４２ ２．０重量部
・水 ７９．０重量部
（処方Ｍインク）
・グリセリン ５．０重量部
・チオジグリコール ５．０重量部
・尿素 ５．０重量部
・イソプロピルアルコール ４．０重量部
・染料Ｃ．Ｉ．アシッドレッド２８９ ２．５重量部
・水 ７８．５重量部
（処方Ｃインク）
・グリセリン ５．０重量部
・チオジグリコール ５．０重量部
・尿素 ５．０重量部
・イソプロピルアルコール ４．０重量部
・染料Ｃ．Ｉ．ダイレクトブルー１９９ ２．５重量部
・水 ７８．５重量部
（処方Ｋインク）
・グリセリン ５．０重量部
・チオジグリコール ５．０重量部
・尿素 ５．０重量部
・イソプロピルアルコール ４．０重量部
・染料フードブラック２ ３．０重量部
・水 ７８．０重量部
【００７８】
記録媒体としては電子写真・インクジェット共用紙（ＰＢ・ＰＡＰＥＲ：キヤノン株式会社製）を用いた。これらの色材インク、記録媒体を用いて記録を行った。
【００７９】
記録動作制御は、前述の図８に示すフローチャートに示す手順に従って行った。すなわち、まず、図４に示す階段チャートを出力し、その階段チャートを不図示の光学的センサー（スキャナ）によって４８００ｄｐｉの読み取り解像度で読み取る。この際、ノズルと階段チャートの対応をとるべくチャートに予めマークをつけておきそのマークの位置からノズルと階段チャートの位置関係を合わせておくとよい。そして、各階段チャートの一本の線を細線化処理し、インクドットの重心を求め、理想とする着弾位置からのインクドットのＹよれ値を測定し、全ノズルについてノズルプロファイルを作成した。
【００８０】
各ノズルから吐出されるインクドットの着弾精度は、σ値で６μｍ、最大よれは＋２５μｍであった。このノズルプロファイルを用いて、前述の式により、予測される各記録マトリックスラインの記録濃度を計算し、ヘッド補正データ（ＨＣデータ）を作成した。記録すべき画像の記録データにおける濃度階調値を、各ノズルで記録する記録ライン毎に補正を行い、上述の複数種のインクを用いて記録を行った。その結果、すじむらは低減し、白すじの発生が抑えられた高品位な画像が得られた。
【００８１】
これに対し、上記実施例のヘッド補正処理を行わず、その他の条件を同一のして記録を実行したところ、得られた画像は、白すじが発生した品位の低い画像となった。
また、従来のヘッドシェーディング処理を行って記録したところ、濃度むらは低減されたが、依然としてすじむらが目につく画像が形成され、本実施例によって得られた画像に比べ、画像品位の低下は明らかであった。
【００８２】
（その他）
ところで、本発明は、インクジェット記録方式の中でも熱エネルギーを利用して飛翔的液滴を形成し、記録を行うインクジェット方式の記録ヘッドを用いた記録装置において特に優れた効果をもたらすものとなっている。
【００８３】
その代表的な構成や原理については、例えば、米国特許第４７２３１２９号明細書、同第４７４０７９６号明細書に開示されている基本的な原理を用いて行うものが好ましい。この方式は所謂オンデマンド型、コンティニュアス型のいずれにも適用可能であるが、特に、オンデマンド型の場合には、液体（インク）が保持されているシートや液路に対応して配置されている電気熱変換体に、記録情報に対応していて核沸騰を越える急速な温度上昇を与える少なくとも一つの駆動信号を印加することによって、電気熱変換体に熱エネルギを発生せしめ、記録ヘッドの熱作用面に膜沸騰を生じさせて、結果的にこの駆動信号に一体一で対応した液体（インク）内の気泡を形成できるので有効である。この気泡の成長、収縮により吐出用開口を介して液体（インク）を吐出させて、少なくとも一つの滴を形成する。この駆動信号をパルス形状とすると、即時適切に気泡の成長収縮が行われるので、特に応答性に優れた液体（インク）の吐出が達成でき、より好ましい。このパルス形状の駆動信号としては、米国特許第４４６３３５９号明細書、同第４３４５２６２号明細書に記載されているようなものが適している。なお、上記熱作用面の温度上昇率に関する発明の米国特許第４３１３１２４号明細書に記載されている条件を採用すると、さらに優れた記録を行うことができる。
記録ヘッドの構成としては、上述の各明細書に開示されているような吐出口、液路、電気熱変換体の組合わせ構成（直線状液流路または直角液流路）の他に熱作用部が屈曲する領域に配置されている構成を開示する米国特許第４５５８３３３号明細書、米国特許第４４５９６００号明細書を用いた構成も本発明に含まれるものである。
【００８４】
加えて、複数の電気熱変換体に対して、共通するスリットを電気熱変換体の吐出部とする構成を開示する特開昭５９−１２３６７０号公報や熱エネルギの圧力波を吸収する開孔を吐出部に対応させる構成を開示する特開昭５９−１３８４６１号公報に基づいた構成としても本発明の効果は有効である。すなわち、記録ヘッドの形態がどのようなものであっても、本発明によれば記録を確実に効率良く行うことができるようになるからである。
【００８５】
さらに、記録装置が記録できる記録媒体の最大幅に対応した長さを有するフルラインタイプの記録ヘッドに対しても本発明は有効に適用できる。そのような記録ヘッドとしては、複数記録ヘッドの組合せによってその長さを満たす構成や、一体的に形成された１個の記録ヘッドとしての構成のいずれでも良い。
【００８６】
加えて、上例のようなシリアルタイプのものでも、装置本体に固定された記録ヘッド、あるいは装置本体に装着されることで装置本体との電気的な接続や装置本体からのインクの供給が可能になる交換自在のチップタイプの記録ヘッド、あるいは記録ヘッド自体に一体的にインクタンクが設けられたカートリッジタイプの記録ヘッドを用いた場合にも本発明は有効である。
【００８７】
また、本発明の記録装置の構成として、記録ヘッドの吐出回復手段、予備的な補助手段等を付加することは本発明の効果を一層安定できるので、好ましいものである。これらを具体的に挙げれば、記録ヘッドに対してのキャッピング手段、クリーニング手段、加圧あるいは吸引手段、電気熱変換体あるいはこれとは別の加熱素子あるいはこれらの組み合せを用いて加熱を行う予備加熱手段、記録とは別の吐出を行う予備吐出手段を挙げることができる。
【００８８】
本発明においては、上述した各インクに対して最も有効なものは、上述した膜沸騰方式を実行するものである。
【００８９】
【発明の効果】
以上説明したように本発明においては、記録ヘッドのノズルの吐出特性を表すノズル情報を作成し、作成されたノズル情報と前記記録データとに基づき、前記各ノズルから吐出されるインク滴が形成すべき画像に与える影響を予測し、その予測結果に基づき各ノズルにおけるインク滴の吐出状態を補正する補正情報を作成し、その補正情報に基づきノズルの駆動を制御するようにしたため、例えば、記録ヘッドのノズルから吐出したインク滴が、何らかの理由により理想的着弾位置に正確に着弾しない場合、あるいは各ノズル毎に多少の吐出量の違いがある場合などにおいても、ヘッド補正を行うことで記録画像上に発生するすじむらなどの画像品位の劣化を大幅に改善することができる。
【００９０】
また、記録ヘッドの各ノズルの中に、着弾位置が大きくよれる不良ノズルが存在していた場合、従来のシェーディングでは画像の劣化を解消することができなかったが、本発明によれば、このインク滴の大きなよれによる画像の劣化を補正することが可能となる。従って、上記のような不良ノズルが発生したインクヘッドにあっても、これを交換することなく長期間にわたって使用することができ、ランニングコストを大幅に低減することができると共に、エコロジーの観点からも望ましい結果を得ることができる。また、記録ヘッドの製造上の歩留まりを実質的に向上させることができるため、記録ヘッドの製造コストを低減することも可能となる。
【００９１】
また、本発明における以上の効果は、複数のノズルを配列してなるノズル群の１回の記録走査によって画像を完成させる記録方式において特に顕著であるが、同一の記録領域に対し複数回の記録走査を異なるノズル群を用いて行うようにした所謂マルチパス記録に本発明を適用すれば、画像に生じるすじむらを一層低減することができるようになる。従って、本発明は、いかなるインクジェット記録方式にも有効である。
【図面の簡単な説明】
【図１】本発明の一実施形態にかかるインクジェット記録装置の概略構成を示す正面図である。
【図２】図１に示すインクジェット記録ヘッドの構造を拡大して示す説明図である。
【図３】本発明の実施形態における制御系の構成の一例を示すブロック図である。
【図４】記録ヘッドにおける不良ノズルを検知するための階段チャートの一例であり、（ａ）は正常なノズルを有する記録ヘッドによって形成された階段チャートを、（ｂ）は１８番目と２８番目と３０番目に不良ノズルが存在する記録ヘッドによって形成された階段チャートをそれぞれ示している。
【図５】記録ヘッドにおける不良ノズルを検知するためのドットチャートの一例であり、（ａ）は正常なノズルを有する記録ヘッドによって形成されたドットチャートを、（ｂ）は１８番目と２８番目と３０番目に不良ノズルが存在する記録ヘッドによって形成されたドットチャートをそれぞれ示している。
【図６】記録ヘッドのノズルから吐出されたインク滴によって記録媒体上に形成される様々なインクドットの形状を説明する説明図である。
【図７】本発明の実施形態に適用する理想マトリックスとその理想マトリックスにインク滴が着弾した状態を示す説明図であり、（ａ）はインク滴が記録媒体上に理想的に着弾した状態を示し、（ｂ）はインク滴が記録媒体上に理想的に着弾しなかった状態を示す図である。
【図８】本発明の第１の実施形態における制御動作の一例を示すフローチャートである。
【図９】本発明の第１の実施形態において各ノズルから吐出されたインク滴によって形成される複数のインクドットの一つの理想マトリックスラインへの影響度を説明するための説明図であり、（ａ）は記録ヘッド、理想マトリックス、インク滴が理想的に着弾した状態、およびインク滴が理想的に着弾していない状態をそれぞれ示し、（ｂ）は同図（ａ）に示した着弾ドットの中の中央の３つのインクドットｄ（ｍ−１），ｄ（ｍ）ｄ（ｍ＋１）の形成状態を拡大して示している。
【図１０】本発明の第１の実施形態において各ノズルから吐出されたインク滴によって形成されるインクドットの一つの単位マトリックスへの影響度を説明するための説明図であり、図９（ａ）に示した着弾ドットの中の中央の３つのインクドットｄ（ｍ−１），ｄ（ｍ）ｄ（ｍ＋１）の形成状態を拡大して示している。
【図１１】本発明の第１の実施形態において各ノズルから吐出されたインク滴によって形成される複数のインクドットが一つの理想マトリックスラインに与える影響度を算出する方法を説明するための説明図である。
【図１２】本発明の第２の実施形態おける制御動作を説明するフローチャートである。
【図１３】本発明の第３の実施形態における制御動作を説明するフローチャートである。
【図１４】本発明の第４の実施形態における制御動作を説明するフローチャートである。
【符号の説明】
１ 画像データ入力部
２ 操作部
３ ＣＰＵ
４ 記憶媒体
４ａ 記録マトリクス情報格納部
４ｂ 制御プログラム群格納部
５ ＲＡＭ
６ 画像データ処理部
７ 記録部
８ バスライン
２０ キャリッジ
２１ インクジェット記録ヘッド
２２ インクカートリッジ
２３ フレキシブルケーブル
２４ 記録媒体
２５ 排紙ローラ
２６ 搬送モータ
２７ ガイドシャフト
２８ リニアエンコーダ
２９ 駆動ベルト
３０ キャリッジモータ
３１ キャップ部
３２ 回復ユニット
３３ インク受け[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus and an ink jet recording method for recording an image using an ink containing a coloring material using a multi-nozzle ink jet recording head in which ink discharge ports are arranged in an integrated arrangement. The present invention relates to an inkjet recording apparatus and an inkjet recording method for recording a high-quality recorded image by analyzing and correcting a factor that degrades image quality.
In addition, the present invention is applicable to all devices using recording media such as paper, cloth, leather, nonwoven fabric, OHP paper, and metal. Specific examples of applicable equipment include office equipment such as printers, copiers, and facsimile machines, and industrial production equipment.
[0002]
[Prior art]
With the spread of information processing equipment such as copying machines, word processors, computers, and communication equipment, inkjet recording devices are rapidly spreading as one of the devices that output digital images processed by such equipment. is there. In such a recording apparatus, in order to improve the recording speed, a recording head in which a large number of nozzles including ink discharge ports and liquid paths are integrated is used. Further, in recent years, colorization in information processing equipment has progressed, and in association with this, there has been a demand for colorization in recording apparatuses, and there are those equipped with a plurality of recording heads that eject inks of different colors in response to the request. Commonly used.
[0003]
The ink jet recording method is a non-contact method in which ink, which is a recording liquid, is landed on a recording medium such as paper as flying droplets and the recording medium does not contact the recording head. Recording operation can be performed with noise. In addition, since the density of the ink discharge nozzles can be increased, it is possible to realize high-resolution images and high-speed recording operations at low cost. Furthermore, it is possible to obtain a high-quality image at a low price without requiring special processing such as a phenomenon or fixing on a recording medium such as plain paper.
[0004]
For these reasons, inkjet recording apparatuses are now widely used in various situations. In particular, an on-demand type ink jet recording apparatus can be easily colored, and the apparatus itself can be miniaturized and simplified, so that the demand is expected to increase further in the future. In addition, with the widespread use of color as described above, higher image quality and higher speed tend to increase.
[0005]
[Problems to be solved by the invention]
However, the conventional recording apparatus has the following various problems. That is, in a conventional ink jet recording apparatus using an ink jet recording head in which a plurality of ink discharge nozzles are integrated and arranged, one or a plurality of discharge nozzles are clogged or driven for some reason. When this is not possible, the dots to be recorded by the nozzles will not be recorded on the recording medium. As a result, the non-recorded portion becomes streaks (white streaks) and appears on the image, thus significantly improving the image quality. It was decreasing. In addition, if the discharge state from one or a plurality of discharge nozzles falls into a state that is significantly different from the discharge from other normal nozzles, if the recording operation is continued as it is, white streaks and streaks due to density non-uniformity will occur. This occurred on the image, and the image quality was significantly impaired.
[0006]
Therefore, as a recording method that prioritizes image quality, when a defective nozzle that does not provide a proper discharge state occurs, the cleaning mechanism tries to recover or uses a plurality of nozzle groups that complement each other to perform the same recording. It has also been proposed and implemented to perform so-called multi-pass printing in which an image is completed by manipulating an area a plurality of times to reduce image quality deterioration due to non-ejection nozzles or defective nozzles. However, the multi-pass recording method has a problem that it takes a long recording time to perform recording a plurality of times in one recording area. In addition, the recovery operation by cleaning or the like requires a lot of time and involves consumption of ink that does not directly contribute to recording, resulting in an increase in running cost, which is not preferable from the viewpoint of ecology. It is desirable to limit it to the limit.
[0007]
Also, a technique for improving the image quality by preventing the density unevenness of the recorded image by so-called head shading has been developed. In this head shading, a test pattern having a uniform gradation value is recorded on a recorded image, and the unevenness of the recording density is optically detected. Based on the detection result, addition to the gradation value of the output image is performed. A method of recording with correction such as subtraction is generally known.
[0008]
In addition, in an ink jet recording printer having a recording head in which a plurality of ink discharge nozzles are integrated and arranged, a test pattern having a uniform gradation value is output, and a recording density displacement is optically measured, and a recording density is measured. Assuming that the unevenness in density is uneven due to unevenness in the discharge amount of each nozzle, correct the ink discharge drive method for the discharge amount of each nozzle or perform gamma correction on the recording image corresponding to each nozzle. Etc. have been tried to improve the concentration value.
[0009]
However, the improvement in image quality by such head shading is basically aimed at correcting the unevenness of the size (ejection amount) of the ink droplets ejected from the nozzles. If the ink droplets ejected from the nozzles do not land at the ideal landing position, the image is not improved to the optimum quality, and in particular, the relative scanning between the recording head and the recording medium is performed once. Thus, in the full multi-type ink jet recording using the full line head of the so-called full line recording method for completing the image recording from the recording head, improvement of the image quality is desired.
[0010]
As described above, the conventional inkjet recording method has the above-described problems. In the future, what is necessary for an ink jet recording apparatus is to simultaneously realize higher speed and lower cost in addition to higher image quality, and for this purpose, it is necessary to solve the above-mentioned problems.
[0011]
The present invention has been made in view of the above-mentioned various problems, and even when there are defective nozzles in the nozzles provided in the recording head that cause ink droplets to be greatly swollen, etc. An object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method capable of suppressing the occurrence of the above and enabling appropriate gradation expression and obtaining a high-quality image.
[0012]
[Means for Solving the Problems]
The present invention for achieving the above object has the following configuration.
[0013]
  That is, according to the present invention, a recording head formed by arranging a plurality of nozzles and a recording medium are relatively moved, and ink droplets are ejected from the nozzles on the recording medium in accordance with recording data of an image to be formed. An inkjet recording apparatus for forming an image, wherein each nozzle is based on a landing state of ink droplets ejected from the nozzle on a recording medium.This represents the amount of deviation between the ideal landing position of the ink droplets ejected from the disk and the actual landing position on the recording medium.Nozzle information, Corresponding to each nozzleNozzle information creation means to create, and based on the nozzle information, with respect to a dot position formed by ink droplets ejected from the nozzle, a nozzle corresponding to the dot position and other nozzles located in the vicinity of the nozzle And calculating the ratio of affecting the density of the image for each dot position corresponding to each of the plurality of nozzles,CalculationMeansCalculationBased on the result, correction information generating means for generating correction information for correcting the recording data corresponding to each nozzle, and based on the result of correcting the recording data corresponding to each nozzle according to the correction information, Control means for controlling the drive,The calculation means is configured to determine, based on the shift amount corresponding to each of the plurality of nozzles, an area where a dot formed by an ink droplet ejected from a nozzle corresponding to a predetermined dot position lands on the predetermined dot position; The area where the dots formed by the ink droplets ejected from the nozzles land on the predetermined dot position is determined, and the ratio affects the density of the predetermined dot position.It is characterized by that.
[0014]
  In addition, the present invention relatively moves a recording head having a plurality of nozzles arranged and a recording medium, and ejects ink droplets from the nozzles in accordance with recording data of an image to be formed, thereby forming an image on the recording medium. Ink jet recording method for forming each nozzle based on the landing state of ink droplets ejected from the nozzles on a recording mediumThis represents the amount of deviation between the ideal landing position of the ink droplets ejected from the disk and the actual landing position on the recording medium.Nozzle information, Corresponding to each nozzleNozzle information creation step to be created;Based on the nozzle information, for the dot position formed by the ink droplets ejected from the nozzle, the nozzle corresponding to the dot position and other nozzles located in the vicinity of the nozzle affect the image density. A calculation step for calculating a ratio to be given for each dot position corresponding to each of the plurality of nozzlesAnd saidCalculationOf stepCalculationBased on the result, a correction information generation step for generating correction information for correcting the recording data corresponding to each nozzle, and based on the result of correcting the recording data corresponding to each nozzle according to the correction information, A control step for controlling the drive,In the calculating step, based on the shift amount corresponding to each of the plurality of nozzles, an area where a dot formed by an ink droplet ejected from a nozzle corresponding to a predetermined dot position lands on the predetermined dot position; The area where the dots formed by the ink droplets ejected from the nozzles land on the predetermined dot position is determined, and the ratio affects the density of the predetermined dot position.It is characterized by that.
[0015]
In this specification, the term “nozzle” refers not only to an opening for ejecting ink, but also to a liquid path that communicates with the opening and forms a cylindrical space into which ink to be ejected flows, and ink in the liquid path. Means a structure including discharge energy generating means (for example, an electrothermal transducer, a piezoelectric element, etc.) for generating discharge energy for discharging the liquid from the discharge port.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view showing a schematic configuration of an ink jet recording apparatus according to each embodiment of the present invention. A plurality of ink jet recording heads 21 (21-1 to 21-4) are mounted on the carriage 20, and each ink jet recording head 21 has a plurality of ink ejection openings for ejecting ink. Incidentally, 21-1, 21-2, 21-3, and 21-4 are ink jet recordings for ejecting black (K), cyan (C), magenta (M), and yellow (Y) inks, respectively. It is a head (hereinafter simply referred to as a recording head). A heating element (electrothermal converter) that generates thermal energy for ink ejection is provided inside the ink ejection opening (liquid path) of the recording head 21. The ink cartridge 22 includes ink jet recording heads 21-1 to 21-4 and ink tanks 22-1 to 22-4 that supply ink to them.
[0017]
Control signals and the like to the ink jet recording head 21 are sent via the flexible cable 23. A recording medium 24 such as plain paper, high-quality exclusive paper, OHP sheet, glossy paper, glossy film, postcard or the like is sandwiched between a pair of paper discharge rollers 25 facing each other via a conveyance roller (not shown) to drive the conveyance motor 26. Along with this, it is sent in the arrow direction (sub-scanning direction). The carriage 20 is movably supported by the guide shaft 27 and the linear encoder 28. The carriage 20 reciprocates along the guide shaft 27 in the main scanning direction that intersects (is orthogonal to) the sub-scanning direction along the guide shaft 27 by driving the carriage motor 30 via the driving belt 29. At the time of reciprocal movement, a pulse signal is output from the linear encoder 28, and the position of the carriage 20 can be detected by counting the pulse signal. Further, the heating element of the recording head 21 is driven based on the recording signal as the carriage 20 moves, and forms an image by flying and adhering ink droplets onto the recording medium.
[0018]
A recovery unit 32 having a cap portion 31 is installed at the home position of the carriage 20 set outside the region in the main scanning direction where the recording operation is performed on the recording medium. When recording is not performed, the carriage 20 is moved to the above-described home position, and the ink discharge port surfaces of the corresponding inkjet recording heads 21 are sealed by the caps 31-1 to 31-4 of the cap unit 31, so that the ink solvent is removed. Prevents clogging due to thickening of ink, sticking or adhesion of foreign matters such as dust due to evaporation.
[0019]
Further, the capping function of the cap unit 31 is used for empty ejection in which ink is ejected to the cap unit 31 in a state separated from the ink ejection port in order to eliminate ejection failure and clogging of the ink ejection port with low recording frequency. The pump (not shown) is operated in a state where the ink discharge port surface is sealed with the cap portion 31, and the ink is sucked from the ink discharge port, which is used to recover the discharge function of the discharge port that caused the discharge failure. Reference numeral 33 denotes an ink receiving portion, which performs preliminary ejection toward the ink receiving portion 33 when each of the ink jet recording heads 21-1 to 21-4 passes through the upper portion of the ink receiving portion 33 immediately before recording. In addition, by disposing a wiping member (blade or the like) (not shown) at a position adjacent to the cap portion 31, the ink discharge port forming surface of the recording head 21 can be cleaned.
[0020]
Next, FIG. 2 is an explanatory diagram showing an enlarged configuration of the recording head 21 described above. In FIG. 2, the recording head has a large number of ink discharge nozzles n in a direction substantially perpendicular to the main scanning direction. In this figure, an example in which the ink discharge nozzles are configured in two rows in one print head is shown, but it may be one row or more than three rows, and it is not necessary to line up with linearity. Also, as shown in FIG. 2, the interval W1 between adjacent nozzles in the sub-scanning direction is referred to as the recording head resolution, nozzle pitch, and nozzle density.
[0021]
In addition, this recording head is configured to perform recording corresponding to the width W of the nozzle row by ejecting ink while moving the recording head in the direction of the arrow (main scanning direction) in the figure. The operation (ink ejection operation) can be performed by one or both of the forward and backward movements of the recording head. Furthermore, the same number of recording heads as the number of ink colors used for recording are prepared. For example, when performing full-color recording using three colors of cyan, magenta, and yellow, three recording heads are prepared. When performing monochrome recording using only black ink, one recording head is prepared. Just do it. In the case of recording using dark and light inks, a recording head may be prepared for each of dark cyan, light cyan, dark magenta, light magenta, dark black, light black, dark yellow, light yellow, Further, it is possible to use a recording head that discharges special color ink.
[0022]
The ink jet recording method applicable to the present invention is not limited to the bubble jet (registered trademark) method using a heating element (heater), and for example, a continuous type in which ink droplets are continuously ejected into particles. In this case, a charge control type, a divergence control type, or the like may be used. Further, in the case of an on-demand type that ejects ink droplets as necessary, a pressure control method that ejects ink droplets from an orifice by mechanical vibration of a piezoelectric vibration element can be applied.
[0023]
FIG. 3 is a block diagram showing an example of the configuration of the control system of the ink jet recording apparatus according to each embodiment of the present invention.
In FIG. 3, 1 is an image data input unit for inputting multi-value image data from an image input device such as a scanner or a digital camera, or multi-value image data stored in a hard disk of a personal computer, and 2 is a setting of various parameters. An operation unit 3 having various keys for instructing the start of recording is a CPU as a control means for controlling various arithmetic processes and control operations described later according to various programs in the storage medium.
[0024]
A storage medium 4 stores a control program group 4b such as a control program and an error processing program for controlling the recording apparatus, and nozzle profile information 4a. All recording operations in this embodiment are executed by these programs. As the storage medium 4 for storing the program, a ROM, FD, CD-ROM, HD, memory card, magneto-optical disk, or the like can be used. Reference numeral 5 denotes a RAM used as a work area for various programs in the storage medium 4, a temporary save area for error processing, and a work area for image processing. The RAM 5 can also copy various tables in the storage medium 4, change the contents of the tables, and proceed with image processing while referring to the changed tables.
[0025]
An image data processing unit 6 processes the image data. The input multi-value image data is quantized into N-value image data for each pixel, and the gradation value “T” indicated by each quantized pixel is displayed. The ejection pattern data corresponding to is created. For example, when multi-value image data expressed in 8 bits (256 gradations) is input to the image data input unit 1, the image data processing unit 6 sets the gradation value of the output image data to 25 (= 24 + 1) values. Need to convert. Here, the multi-value error diffusion method is used for the T-value conversion processing of the input gradation image data. However, the image processing method for performing the T-value conversion processing is not limited to the multi-value error diffusion method, and the average density storage method. Any halftone processing method such as a dither matrix method can also be used. Further, by repeating the above-described T-value conversion processing for all the pixels based on the density information of the image, a binary drive signal for ejection and non-ejection for each pixel with respect to each ink nozzle is formed. The nozzle information creation means, the prediction means, the correction information creation means, etc. in the present invention are mainly constituted by the image data processing unit 6 and the CPU 3. It is also possible to control with a printer driver processed in a PC or the like.
[0026]
A recording unit 7 ejects ink based on the ejection pattern created by the image data processing unit 6 to form a dot image on a recording medium, and includes an ink cartridge 22 and a carriage 20. Reference numeral 8 denotes a bus line for transmitting address signals, data, control signals, and the like in the apparatus.
[0027]
Next, using FIG. 4 to FIG. 11, the creation of nozzle information in the recording head, which is one of the features of the present embodiment, the creation method of the recording information of each nozzle performed based on the nozzle information, and the actual The recording operation will be described.
[0028]
Regarding the creation of recording information, first of all, it is detected whether there is a nozzle whose landing position deviates from the desired recording matrix among a plurality of nozzles of the recording head. The first step of the present invention is to know the nozzle information such as the position of the nozzle, the degree thereof, the size of the ink droplet that lands as needed, and the shape of the landed ink dot.
[0029]
For that purpose, first, for example, a pattern (step pattern) as shown in FIG. 4 is recorded using the apparatus of FIG. The staircase pattern may be a pattern in which a short straight line is recorded by ejecting color material dots continuously or discontinuously from each nozzle, for example, every 8 nozzles, and recording is performed for the necessary nozzles. By using this staircase pattern, it is possible to know how much the ink dots ejected from the nozzles have landed on the desired ideal recording matrix MT in the vertical direction in the figure. Specifically, this recorded matter (stair chart) is read and scanned using a sensor (not shown) to measure how many μm it deviates from the ideal landing position, and the measured deviation is referred to as nozzle profile information. To do. Alternatively, the position and amount of displacement may be determined visually without using a sensor, and nozzle profile information may be obtained based on the nozzle information, and that information may be input to the recording apparatus. This nozzle information was prepared for each recording head.
[0030]
The ideal landing position of the nozzle can be determined by, for example, creating an accurate ideal stair chart in advance using general printing or silver halide photography, recording it, and measuring the deviation from the ideal recording matrix. It is also possible to read the recorded stair chart with a scanner (not shown), collate the position of the recording matrix while taking into account the position of each nozzle, and calculate the amount of deviation from the stair chart.
[0031]
Furthermore, as shown in FIG. 5, a dot chart for forming independent ink dots on the recording medium from each nozzle is recorded, and the above-described method is used to shift the X and Y directions from the ideal recording matrix. The nozzle profile information may be created by reading the ink dot diameter and the ink dot shape.
[0032]
The image recording signal can be generated by a method used in a normal ink jet recording apparatus. In the present embodiment, the input image is first color-separated into three primary colors such as C, M, and Y so as to correspond to the heads of each color, and then the color-separated image of each color is binarized by an error diffusion method.
[0033]
Next, a method for creating head correction (HC) data based on the nozzle profile, and a recording process for converting an image to be recorded based on the HC data and controlling ejection and non-ejection of the nozzle group of the recording head Describes how to create data.
[0034]
FIG. 7 shows a basic conceptual diagram of this embodiment. That is, FIG. 7 shows an ideal recording matrix MT and a state where ink dots have landed ideally along the ideal recording matrix MT. The ideal recording matrix MT mentioned here is a matrix virtually set on the recording medium. When a solid image is formed by arranging and arranging ink dots having a fixed shape in a matrix on the recording medium, each dot The minimum unit recording range corresponding one-to-one is the unit matrix MT1. The unit matrix may be referred to as a pixel. The ideal recording matrix MT of this embodiment shown in FIG. 7 has a square unit matrix MT1 arranged in a grid pattern in order to simplify the description. However, the arrangement of the unit matrix MT1 does not have to be a grid pattern, depending on the resolution and recording density of the image. The unit matrix MT1 may have a shape other than a square. For example, a unit matrix on a rectangle can be formed in the main scanning direction with a pitch twice that in the sub-scanning direction.
[0035]
When ink is landed on the ideal recording matrix MT, the ink dots are normally landed on the recording medium in a substantially circular state. Therefore, it is assumed that the shape of the ink dots that have landed ideally is a perfect circle, and the diameter of the perfect circle is set to be the same as the distance between the diagonals of the unit matrix MT1.
[0036]
Here, FIG. 7A shows a state where ink dots have landed ideally. The dots shown here cause ink droplets to be ejected from all nozzles while moving a recording head (not shown) having a nozzle group in which eight nozzles are arranged in the vertical direction along the X direction of the main scanning direction. 7A schematically shows a state in which a solid image is recorded. FIG. 7A shows a state where ink droplets have landed ideally on the recording medium, and FIG. 7B shows a state where ink droplets have landed on the recording medium. Each of the states that did not land ideally is shown.
[0037]
In the state shown in FIG. 7A, the ink droplets ejected from each nozzle of the recording head have landed properly on each unit matrix MT1 in the ideal recording matrix MT without any deviation. The arrangement order in the vertical direction (Y) is the same as the arrangement order in the vertical direction of the nozzles in the recording head. For example, the third dot d3 from the top in the illustrated dot is a dot ejected from the third nozzle from the top in each nozzle of the recording head, and the fourth from the top in the illustrated dot. The dot d4 is a dot ejected from the fourth nozzle from the top among the nozzles of the recording head.
[0038]
On the other hand, as a state where the ink droplets ejected from the recording head have not ideally landed on the recording medium, for example, there is a state shown in FIG.
In the figure, a dot d2 formed by landing an ink droplet ejected from the second nozzle is in a state of landing in a state shifted in the X1 direction and the Y2 direction (upper right direction in the figure). Further, the dot d3 formed by the ink droplet ejected from the third nozzle is shifted in the Y1 direction and landed on the matrix to which the ink droplet ejected from the fourth nozzle is to land.
[0039]
  Furthermore, the dot d4 formed by the ink droplet ejected from the fourth nozzle isY2The ink droplets ejected from the third nozzle are landed on the matrix to be landed.
  Further, the dot d6 ejected from the sixth nozzle and landed forms a dot with a large diameter on the recording medium due to factors such as a larger ink ejection amount than other nozzles.
[0040]
Further, the dot d7 formed by the ink droplets ejected from the seventh nozzle has a smaller ejection amount than the other nozzles, or the ejected ink droplets are divided, resulting in the recording medium. A state where small dots are formed is shown.
[0041]
Although the ink dots shown in FIG. 7 are drawn in a perfect circle, the ink dots may not become a perfect circle depending on the type of the recording medium and the state change from ejection to landing. As shown, ink dots may be formed in various shapes other than a perfect circle on the recording medium. For example, if the discharge amount varies among nozzles, the dots differ in size, and the ink penetrates into the paper fibers in the process where ink droplets landed on the recording medium are absorbed and fixed on the paper surface. If the ink droplets are formed in such a complicated shape, the ink droplets do not land vertically at the time of landing, or if a moment is applied by a wind or the like, a phenomenon such as an elliptical shape or a split may occur.
[0042]
Furthermore, in addition, in the process where ink droplets are ejected from the nozzles of the recording head and land on the recording medium, the ejection amount is uneven, the ejected ink droplets do not fly in the correct direction, or are in flight And even after landing on the recording medium, it is affected by unevenness of the recording medium, permeability to the recording medium, fixing properties, etc., so it is completely uniform on the recording medium. It is difficult to form a dot having a proper shape at an appropriate position. That is, it is extremely difficult to form an ideal dot as shown in FIG.
[0043]
Therefore, conventionally, correction processing such as head shading is performed. In conventional head shading, a recording position by a nozzle with a large discharge amount becomes an image with high density, and a recording position by a nozzle with a small discharge amount becomes an image with low density, so a chart with a constant density is recorded on the recording medium, The recording density is read and correlated with the position of each nozzle, and the output image is corrected so that the portion where the density is high is low and the portion where the density is low is high. Further, the image quality is improved by changing the drive control of each nozzle to shorten the drive pulse of the nozzle having a large discharge amount or increasing the drive voltage of the nozzle having a small discharge amount.
[0044]
However, this head shading correction may not be able to be corrected, and a sufficient effect may not always be obtained. For example, as shown in FIG. 7B, when the ink droplet ejected from the third nozzle and the ink droplet ejected from the fourth nozzle cross and land, the effect of the correction is achieved. May not be obtained. That is, when the density of the third matrix is high, the cause is that there is a problem with the discharge amount of the fourth nozzle, but the density of the dot read as described above is correlated with the nozzle position, and 3 Even if the head shading process for reducing the discharge amount of the second nozzle is performed, the ink dot d3 discharged from the nozzle lands on the fourth matrix, so that the correction of the discharge amount becomes invalid.
[0045]
In addition to this example, when the landing position is deviated from the ideal recording matrix in the X direction or the Y direction, the density of the neighboring matrix lines is increased and the density of the original matrix lines is decreased. Nevertheless, in the conventional head shading, since the deviation amount of the landing position is not considered, correction for increasing the density is applied to the nozzle in which this deviation occurs. For this reason, the density of the recording matrix in the vicinity is further increased, and accurate correction cannot be performed. Conventionally, in order to solve this problem, the recording density values in the vicinity were averaged and processed, but the current inkjet recording apparatus, which is demanding higher image quality, requires a more accurate correction technique. It was.
[0046]
Therefore, in the first embodiment of the present invention, processing is performed according to the procedure shown in the flowchart of FIG. 8 as an example.
First, in step S1, as shown in the stair chart shown in FIG. 4, each chart is recorded so that the ink droplets ejected from each nozzle can be observed on the recording medium, and then the chart is not shown. Reading with an optical sensor (step S2), and based on the read data, the amount of deviation of the landing position from the ideal recording matrix is measured. This measurement may be performed visually. Further, as the measurement of the ejection amount of ink droplets, the size and shape of the landing dots may be measured using an optical sensor (not shown) by recording the dot chart of FIG.
[0047]
As a result of this measurement, ink droplets that formed these dots were ejected when they did not land on the ideal recording matrix, when they differed from the ideal dot diameter, or when the ink dot shape differed from the ideal dot shape, etc. The nozzle is determined as a defective nozzle. Or you may progress to the step which produces the nozzle profile of substantially all the nozzles automatically, without performing determination of a bad nozzle especially.
[0048]
If there is no nozzle determined to be a defective nozzle, the process proceeds to step S6, and a desired image recording operation is performed without performing correction processing.
[0049]
If it is determined in step S2 that there is a defective nozzle, nozzle profile information described later is created for each nozzle in the nozzle group constituting the recording head. That is, in this embodiment, the case where the Y twist value is used as an important parameter of the nozzle profile information is shown. The Y twist value is ejected from the nozzles when the direction of the nozzle array (sub-scanning direction) constituting the recording head is the Y direction and the main scanning direction for moving the recording head relative to the recording medium is the X direction. It means the amount of deviation in the Y direction between the ink droplet landing position (dot center position) and the ideal recording matrix MT center position (ideal grid point). Therefore, when one scan (one pass) printing is performed, if the nozzle pitch is set to be the same as the size of the ideal landing matrix and the nozzle pitch is 1200 dpi (about 20 μm), the nozzle is ejected from the mth nozzle. If the landing position of the ink droplet is shifted to the (m−1) th or (m + 1) th nozzle side by about half a pixel, the Y twist value is +10 μm or −10 μm, and this value is stored as nozzle profile information. . Also, whether the dot diameter of the ink dot (for example, it is caused by the magnitude of the ejection amount) is larger or smaller than the ideal ink dot diameter can be managed as nozzle profile information.
[0050]
Returning to FIG. 8 again, the operation after step S4 will be described. As described above, the Y deflection value of the defective nozzle is measured in step 3, and nozzle profile information is created based on the measured value (step S3). Next, HS data is created by referring to the nozzle profile information (step S4), and HC data (head correction table) corresponding to the size of the recording data of the input image is created from the HS data (step S5). ). Then, the recording data of the input image is converted using the created HC data, and the recording operation is performed according to the recording data (step S6).
[0051]
Here, the creation of each piece of information performed after step S4 in FIG. 8 will be described in more detail with reference to FIGS.
[0052]
In FIG. 9A, from the left, the recording head 21, the ideal recording matrix MT, the state where ink droplets have landed ideally on the ideal recording matrix MT, and the ink droplets ideally onto the ideal recording matrix MT. Each of the states that did not land is shown schematically. Here, in order to simplify the description, a recording head 21 in which five nozzles are provided is schematically shown. FIG. 9B is an explanatory diagram showing, in an enlarged manner, the formation state of the three central ink dots in the landing dots shown in FIG.
[0053]
Each data is created by identifying a nozzle that has ejected at least a portion of the ink dots for each matrix line of the ideal recording matrix MT as a nozzle (cause nozzle) that has a density effect on the matrix line. This is done by determining the proportion of the portion that affects the recording density (hereinafter, this portion is referred to as the affected portion).
[0054]
For example, as shown in FIG. 9B, d (m−1) and d (m) are generated by ink droplets ejected from the m−1th, mth, and m + 1th nozzles with respect to the m matrix line. ) And d (m + 1) dots are determined as follows. That is, the ink dot d (m−1) formed by the (m−1) th nozzle is applied to the m matrix line, that is, the portion that has a density influence on the line (the nozzle shown on the left side in FIG. 9B). The ratio of the hatched portion in the row is 10% of the ideal dot, and the portion of the ink dot ejected from the mth nozzle on the m matrix line (in the nozzle row shown in the center in FIG. 9B). The hatched portion is 80% of the ideal dot, and the portion of the ink dot ejected from the (m + 1) th nozzle on the m matrix line is hatched in the nozzle row shown on the right side in FIG. 9B. (Part) is 5% of the ideal dot. This can be said to be a state where a density of 95% is recorded with respect to an ideal landing state.
Here, attention is paid to the lines on the recording matrix, but as shown in FIG. 10, the ratio of the affected portion of each dot may be obtained individually for each unit matrix MT1.
[0055]
The ratio (influence degree) of the affected part with respect to each matrix line described above can be obtained as follows by referring to the nozzle profile information, in particular, the Y translation value therein.
[0056]
For example, it is assumed that the nozzle pitch (corresponding to the recording matrix) is arranged at 20 μm (corresponding to 1200 dpi), and ink dots having a dot diameter of 30 μm are formed on the recording medium from any nozzle, and further, m−1 to m The Y direction value of the dot by the (m−1) th nozzle is +5 μm, the Y value of the dot by the mth nozzle is 10 μm, and the Y value of the dot by the (m + 1) th nozzle is 5 μm. As shown in FIG. 11 (a), the dots recorded on the m matrix line are based on the dots by the (m-1) th nozzle, the dots by the mth nozzle itself, and the dots by the (m + 1) th nozzle, respectively. It is calculated by the following formula.
[0057]
That is, as shown in FIG. 11 (b), assuming that the dot radius is R, the dot area is S, the Y twist value is Y, and the width of the recording matrix line is P, the dot d (m−1) is m matrix lines. Ratio that affects concentration (degree of influence)_{m − 1}(L) (L is a number indicating the position of the matrix line)

Similarly, the degree of influence Z of the dot d (m + 1) on the m matrix line Z_{m +1}(L) can be obtained.
The center angle θ is an angle formed by two line segments (radius) connecting two intersections of dots and m matrix lines and the center of the dots.
[0058]
Also, the degree of influence Z on the m matrix line of d (m)_m(L) can be obtained by the following equation.
Z_m(L) = 100−Z_m(L-1) -Z_m(L + 1) (%)
[0059]
Here, when the value of the radius R of the dot is different for each nozzle, it can be calculated by substituting an individual value.
Also, when the dot shape is not a perfect circle, the calculation is complicated, but it can be obtained similarly. In this case, a complicated dot shape may be approximated to a predetermined shape that can be easily calculated.
[0060]
In this way, by analyzing the recording state of a certain matrix line (L), particularly the nozzle that affects the density, the density of the line (L) can be predicted.
That is, the density by the ideal recording dot is D_iAnd the line L-th predicted concentration is D_LThen,
Predicted concentration D_LIs expressed by the following equation that integrates the degree of influence Z (L) from the mth to m + b (a and b are positive integers) ejected from the neighboring nozzles and applied to the recording line L. That is,
D_L= K_den(Z_m-a(L) ... Z_m-1(L) + Z_m(L) + Z_{m + 1}(L) ... Z_{m + b}(L))
[0061]
Where k_denIs a coefficient for obtaining the actual density from the area of the dots, and can be obtained by measuring the density of the recorded matter.
The coefficient H used for head correction_confIs
H_conf(L) = k_head× D_L/ D_i
It is possible to know the state of contribution of the recording matrix to the actual density on the recording medium.
[0062]
Where k_headIs a coefficient for finely adjusting the coefficient K, which varies depending on the recording medium, recording environment, etc., and can be obtained experimentally.
This H_confThe head shading is carried out by correcting the image to be recorded using, or by changing the ejection amount by controlling the drive signal related to the ejection of each nozzle.
[0063]
As described above, in the above-described embodiment, when each line is recorded, even if it is affected by density due to dots formed by landing on the matrix line, the recording correction is performed in consideration of the influence. Therefore, even in a recording head having a nozzle that causes an ink droplet landing error in the Y direction, a good correction effect can be obtained and a high-quality image can be formed. Can do.
[0064]
In the above embodiment, the correction coefficient of the nozzle corresponding to each matrix line L is calculated. However, the degree of influence from adjacent matrix lines obtained for one matrix line ... Z_m-1(L), Z_m(L), Z_{m + 1}(L)... May be used to obtain a correction coefficient for the (m-1) th nozzle that records the matrix line L-1 adjacent to the matrix line. Specifically, the coefficient H used for head correction_nozzIs calculated as follows. That is, by the processing of the line L, the head correction is also performed for the m−1th nozzle that should be originally recorded on the line L−1, and the nozzle that affects the density of the line L and / or the nozzle. Correction is also performed on the image recorded by the nozzle.
[0065]
When the nozzles of the ink dots that affect the ink dots by the nozzle m are L-1, L, and L + 1, the count H used for head correction_nozzIs obtained as follows.
H_nozz(L) = Z_m(L-1) × H_conf(L-1) + Z_m(L) x H_conf(L) + Z_m(L + 1) × H_conf(L + 1)
Although omitted in the above equation, a coefficient may be provided for each term as necessary.
That is, the correction coefficient for the m-th nozzle that records the L matrix line is the matrix line affected by the ink dots formed by the ink droplets ejected from the m-th nozzle (L−1, L + 1 in the above equation). The correction of the predicted recording density and the ideal recording density are also taken into consideration.
[0066]
In other words, the ink dots ejected from the m-th nozzle are in accordance with the status of the L-1 matrix line and the L + 1 matrix line based on the influence on the L-1 matrix line and the influence on the L matrix line and the L + 1 matrix line. Thus, the head correction data is calculated.
According to the above method, for example, even when an ink dot is formed on the side of the matrix line adjacent to the matrix line of interest, the image data is corrected for the nozzles that have affected the matrix line. Correction of the matrix line can be realized by correcting the discharge amount of the nozzle and / or a more excellent correction function can be obtained.
[0067]
Although the present invention is particularly effective for a one-pass printing operation, a so-called multi-pass in which an image in the same printing area is completed by scanning a plurality of times with different nozzle groups of the printing head. The present invention is also effective in system recording. In multi-pass printing, after a defective nozzle is detected, the area recorded by the defective nozzle during different scanning scans is recorded by another nozzle group, so that a reduction in image quality due to one defective nozzle is reduced. However, since the present invention can prevent image quality deterioration due to defective nozzles with a simple processing method in substantially the same printing scan, it is possible to obtain a higher quality image in combination with the superiority of the multi-pass printing method. Can be formed.
[0068]
[Second, Third, Fourth Embodiment]
In the first embodiment, the Y dot value of the ink dot is used as an important parameter in setting the nozzle profile information. However, the present invention uses not only the Y dot value but also other values as parameters. It is also possible.
[0069]
For example, in the second embodiment of the present invention shown in FIG. 12, as shown in step S13, not only the Y shading value 13 of the defective nozzle but also the dot diameter is used as the parameter. In the third embodiment of the present invention shown in FIG. 13, as shown in step S23, the X warp value is used in addition to the Y warp value and the dot diameter, and the fourth embodiment of the present invention shown in FIG. In the embodiment, as shown in step S33, in addition to the Y twist value, the dot diameter, and the X twist value, the dot shape is used as a parameter.
[0070]
As a result of setting more parameters as in the second to fourth embodiments, more precise information can be obtained as nozzle profile information, compared to the first embodiment. It has become possible to obtain an image that is more excellent in gradation and less affected by streaking. 12 to 14, steps other than the above-described steps S13, S23, and S33 are substantially the same as steps S1, S2, and S4 to S6 described in the first embodiment.
[0071]
In addition, the present invention can be applied to any inkjet recording apparatus that uses a plurality of dark and light inks and large and small dots for each color without any trouble. Even in such a case, higher-order image quality is reproduced on a recording medium. can do.
[0072]
In addition, as shown in FIG. 2, the present invention has a nozzle group in which a plurality of nozzles are arranged substantially perpendicularly to the recording direction, and the interval between adjacent nozzles that can be recorded in the same scan is recorded. Particularly effective for an inkjet recording apparatus having an inkjet recording head arranged approximately at intervals corresponding to each pixel of an image to be printed, that is, a full-line type inkjet recording apparatus in which image recording is completed in one scan It is. This full-line type ink jet recording apparatus has an advantage that the recording apparatus can basically be configured with a simpler configuration than a multi-pass printer, and the recording speed is remarkably high, and the present invention is applied. As a result, improvement in image quality can be achieved, thereby realizing an ink jet recording apparatus that is excellent in all aspects of cost, recording speed, and image quality.
[0073]
Here, when the interval between adjacent nozzles is larger than the interval between adjacent lines of the recording matrix, that is, when the resolution of the recording head is lower than the resolution of the recording matrix, the image recording is performed by the multi-pass method. Or other high-resolution recording heads that eject ink droplets of the same color. In this case, even if other recording heads having different resolutions are used, since the recording can be performed in the same manner as recording in the recording matrix with substantially the same scanning, the present invention can be suitably applied. Also, it can be realized by multi-pass recording. However, as described above, an ink jet printer can be configured with a simple configuration and the high-speed recording is possible when the adjacent nozzles are substantially close to each other. Preferably used.
[0074]
Although it depends on the purpose of recording an image, it is desirable that the resolution of adjacent nozzles be as follows. For example, when it is necessary to record an image of a small size such as a pocket photograph with high image quality by ink jet recording, the interval between adjacent nozzles is 300 dpi if the ink droplet ejection amount is about 40 pl ± 10. It is preferably set to about (100 μm), and if the discharge amount is about 10 pl ± 5, it is preferably close to about 600 dpi (40 μm), more preferably about 5 pl ± 2. If it is 1200 dpi (20 μm) and the discharge amount is about 2 pl ± 1, it is desirable to set it to 2400 dpi (10 μm). Also, unlike the case of viewing an image in a close state as in a pocket photo, when viewing an image from a distance, if a large size recorded matter is to be obtained, a nozzle with a larger discharge amount is relatively Recording is performed with a nozzle row having a large nozzle interval, but the present invention is also suitable in this case.
[0075]
Further, the present invention is not limited to a recording apparatus using a recording head that discharges ink by heat energy generated from an electrothermal transducer, but a recording head that discharges ink using a piezoelectric element such as a piezo. The present invention can be applied to any recording apparatus as long as it is an inkjet recording apparatus that discharges ink from nozzles.
[0076]
【Example】
Examples of the present invention will be described below.
<Example 1>
An example in which recording is performed by the above-described ink jet recording apparatus and recording method according to the first embodiment of the present invention will be described. The recording head had a resolution of 1200 dpi and 4096 nozzles were arranged, and the ink ejection amount (ink droplet amount) at one time was set to 4.5 ± 0.5 pl.
[0077]
The composition of the ink containing the color material is as follows.
(Prescription Y ink)
・ Glycerin 5.0 parts by weight
・ Thiodiglycol 5.0 parts by weight
・ 5.0 parts by weight of urea
・ Isopropyl alcohol 4.0 parts by weight
Dye C. I. Direct Yellow 142 2.0 parts by weight
・ 79.0 parts by weight of water
(Prescription M ink)
・ Glycerin 5.0 parts by weight
・ Thiodiglycol 5.0 parts by weight
・ 5.0 parts by weight of urea
・ Isopropyl alcohol 4.0 parts by weight
Dye C. I. Acid Red 289 2.5 parts by weight
・ 78.5 parts by weight of water
(Prescription C ink)
・ Glycerin 5.0 parts by weight
・ Thiodiglycol 5.0 parts by weight
・ 5.0 parts by weight of urea
・ Isopropyl alcohol 4.0 parts by weight
Dye C. I. Direct Blue 199 2.5 parts by weight
・ 78.5 parts by weight of water
(Prescription K ink)
・ Glycerin 5.0 parts by weight
・ Thiodiglycol 5.0 parts by weight
・ 5.0 parts by weight of urea
・ Isopropyl alcohol 4.0 parts by weight
・ Dye Food Black 2 3.0 parts by weight
・ Water 78.0 parts by weight
[0078]
As a recording medium, electrophotographic / inkjet paper (PB / PAPER: manufactured by Canon Inc.) was used. Recording was performed using these color material inks and recording media.
[0079]
The recording operation control was performed according to the procedure shown in the flowchart shown in FIG. That is, first, the stair chart shown in FIG. 4 is output, and the stair chart is read at a reading resolution of 4800 dpi by an optical sensor (scanner) not shown. At this time, in order to make correspondence between the nozzle and the stair chart, it is preferable to mark the chart in advance and match the positional relationship between the nozzle and the stair chart from the position of the mark. Then, one line of each stair chart was thinned, the center of gravity of the ink dots was obtained, the Y deflection value of the ink dots from the ideal landing position was measured, and nozzle profiles were created for all nozzles.
[0080]
The landing accuracy of the ink dots ejected from each nozzle was 6 μm in terms of σ value, and the maximum deflection was +25 μm. Using this nozzle profile, the recording density of each recording matrix line predicted was calculated by the above-described equation, and head correction data (HC data) was created. The density gradation value in the recording data of the image to be recorded was corrected for each recording line recorded by each nozzle, and recording was performed using the above-described plural types of ink. As a result, streak unevenness was reduced, and a high-quality image in which the occurrence of white streaks was suppressed was obtained.
[0081]
On the other hand, when the head correction process of the above embodiment was not performed and recording was performed under the same other conditions, the obtained image was a low quality image with white streaks.
In addition, when recording was performed by performing conventional head shading processing, the density unevenness was reduced, but an image with still noticeable streak unevenness was formed, and the image quality was not deteriorated compared to the image obtained by this example. It was clear.
[0082]
(Other)
By the way, the present invention brings about a particularly excellent effect in a recording apparatus using an ink jet recording head that performs recording by forming flying droplets using thermal energy among ink jet recording methods. .
[0083]
As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both a so-called on-demand type and a continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface of the liquid, and as a result, bubbles in the liquid (ink) corresponding to the drive signal can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.
As the configuration of the recording head, in addition to the combined configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action A configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region, is also included in the present invention.
[0084]
In addition, for a plurality of electrothermal transducers, Japanese Patent Application Laid-Open No. Sho 59-123670 that discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer or an aperture that absorbs pressure waves of thermal energy is provided. The effect of the present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461 which discloses a configuration corresponding to the discharge unit. That is, regardless of the form of the recording head, according to the present invention, recording can be performed reliably and efficiently.
[0085]
Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by the recording apparatus. As such a recording head, either a configuration satisfying the length by a combination of a plurality of recording heads or a configuration as a single recording head formed integrally may be used.
[0086]
In addition, even the serial type as shown in the above example can be connected to the main body of the recording head or attached to the main body of the device so that electrical connection with the main body of the device and ink supply from the main body are possible. The present invention is also effective when a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.
[0087]
In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, preheating is performed by using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal converter, a heating element different from this, or a combination thereof. Examples thereof include preliminary discharge means for performing discharge different from the means and recording.
[0088]
In the present invention, the most effective one for each of the above-described inks is to execute the above-described film boiling method.
[0089]
【The invention's effect】
As described above, in the present invention, nozzle information representing the ejection characteristics of the nozzles of the recording head is created, and ink droplets ejected from the nozzles are formed based on the created nozzle information and the recording data. For example, the recording head is configured to predict the influence on the power image, create correction information for correcting the ejection state of the ink droplets at each nozzle based on the prediction result, and control the nozzle drive based on the correction information. Even if the ink droplets ejected from these nozzles do not land exactly at the ideal landing position for some reason, or when there is a slight difference in the ejection amount for each nozzle, the head correction can be applied to the recorded image. Degradation of image quality such as streak in the image can be greatly improved.
[0090]
In addition, when there is a defective nozzle that greatly depends on the landing position among the nozzles of the recording head, the conventional shading cannot solve the image degradation. It is possible to correct image degradation due to large ink droplets. Therefore, even if the ink head has a defective nozzle as described above, it can be used over a long period of time without replacing it, and the running cost can be greatly reduced. Desired results can be obtained. Further, since the manufacturing yield of the recording head can be substantially improved, the manufacturing cost of the recording head can be reduced.
[0091]
The above effects of the present invention are particularly remarkable in a recording method in which an image is completed by a single recording scan of a nozzle group formed by arranging a plurality of nozzles. If the present invention is applied to so-called multi-pass printing in which scanning is performed using different nozzle groups, it is possible to further reduce the unevenness in the image. Therefore, the present invention is effective for any ink jet recording system.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing an enlarged structure of the ink jet recording head shown in FIG. 1;
FIG. 3 is a block diagram showing an example of a configuration of a control system in the embodiment of the present invention.
FIG. 4 is an example of a stair chart for detecting defective nozzles in a print head, (a) is a stair chart formed by a print head having normal nozzles, and (b) is the 18th and 28th charts. Step charts formed by the recording head having the 30th defective nozzle are shown.
FIG. 5 is an example of a dot chart for detecting defective nozzles in a recording head, (a) is a dot chart formed by a recording head having normal nozzles, and (b) is an 18th and 28th dot chart. The dot charts formed by the recording head in which the 30th defective nozzle exists are shown.
FIG. 6 is an explanatory diagram for explaining the shapes of various ink dots formed on a recording medium by ink droplets ejected from the nozzles of the recording head.
FIG. 7 is an explanatory diagram showing an ideal matrix applied to an embodiment of the present invention and a state in which ink droplets have landed on the ideal matrix. FIG. 7A shows a state in which ink droplets have landed ideally on a recording medium. FIG. 6B is a diagram illustrating a state where ink droplets have not landed ideally on the recording medium.
FIG. 8 is a flowchart showing an example of a control operation in the first embodiment of the present invention.
FIG. 9 is an explanatory diagram for explaining the degree of influence of a plurality of ink dots formed by ink droplets ejected from each nozzle on one ideal matrix line in the first embodiment of the present invention; a) shows the recording head, ideal matrix, the state where the ink droplets have landed ideally, and the state where the ink droplets have not landed ideally, and (b) shows the landing dots shown in FIG. The formation state of the central three ink dots d (m−1), d (m) d (m + 1) is enlarged.
FIG. 10 is an explanatory diagram for explaining the degree of influence of an ink dot formed by ink droplets ejected from each nozzle on one unit matrix in the first embodiment of the present invention; The enlarged formation state of the three central ink dots d (m−1), d (m) d (m + 1) among the landing dots shown in FIG.
FIG. 11 is an explanatory diagram for explaining a method of calculating an influence degree of a plurality of ink dots formed by ink droplets ejected from each nozzle on one ideal matrix line in the first embodiment of the present invention. It is.
FIG. 12 is a flowchart illustrating a control operation in the second embodiment of the present invention.
FIG. 13 is a flowchart illustrating a control operation in the third embodiment of the present invention.
FIG. 14 is a flowchart illustrating a control operation according to the fourth embodiment of the present invention.
[Explanation of symbols]
1 Image data input section
2 Operation part
3 CPU
4 storage media
4a Recording matrix information storage unit
4b Control program group storage
5 RAM
6 Image data processor
7 Recording section
8 Bus line
20 Carriage
21 Inkjet recording head
22 Ink cartridge
23 Flexible cable
24 recording media
25 Paper discharge roller
26 Conveyor motor
27 Guide shaft
28 Linear encoder
29 Drive belt
30 Carriage motor
31 Cap part
32 Recovery Unit
33 Ink tray

Claims (6)

Inkjet recording in which a recording head formed by arranging a plurality of nozzles and a recording medium are relatively moved, and ink droplets are ejected from the nozzles according to recording data of an image to be formed to form an image on the recording medium. A device,
Based on the landing state of the ink droplets ejected from the nozzles on the recording medium, nozzle information representing the amount of deviation between the ideal landing position of the ink droplets ejected from each nozzle and the actual landing position on the recording medium. Nozzle information creation means for creating corresponding to each nozzle ;
Based on the nozzle information, for the dot position formed by the ink droplets ejected from the nozzle, the nozzle corresponding to the dot position and other nozzles located in the vicinity of the nozzle affect the image density. A calculating means for calculating a ratio to be given for each dot position corresponding to each of the plurality of nozzles;
Based on the calculation result of the calculating means, and the correction information generation means for generating correction information for correcting the recording data corresponding to each nozzle,
Control means for controlling the drive of each nozzle based on the result of correcting the recording data corresponding to each nozzle according to the correction information,
The calculation means is configured to determine, based on the shift amount corresponding to each of the plurality of nozzles, an area where a dot formed by an ink droplet ejected from a nozzle corresponding to a predetermined dot position lands on the predetermined dot position; An ink jet recording apparatus characterized in that an area where dots formed by ink droplets ejected from the nozzle land on the predetermined dot position is determined to have a ratio that affects the density of the predetermined dot position . 2. The inkjet according to claim 1 , wherein the nozzle information creating unit further obtains a size of an ink dot formed by an ink droplet landed on a recording medium as nozzle information representing a discharge characteristic of the nozzle. Recording device. In the recording of an image to be formed, the correction unit creates correction information for correcting a discharge state of a nozzle that cannot obtain an ideal landing state based on a calculation result of the calculation unit. An ink jet recording apparatus according to claim 1 or 2. Inkjet recording in which a recording head formed by arranging a plurality of nozzles and a recording medium are relatively moved, and ink droplets are ejected from the nozzles according to recording data of an image to be formed to form an image on the recording medium. A method,
Based on the landing state of the ink droplets ejected from the nozzles on the recording medium, nozzle information representing the amount of deviation between the ideal landing position of the ink droplets ejected from each nozzle and the actual landing position on the recording medium. Nozzle information creation step to create corresponding to each nozzle ,
Based on the nozzle information, for the dot position formed by the ink droplets ejected from the nozzle, the nozzle corresponding to the dot position and other nozzles located in the vicinity of the nozzle affect the image density. A calculation step of calculating a ratio to be given for each dot position corresponding to each of the plurality of nozzles ;
Based on the calculation result of the calculating step, the correction information generating step of generating correction information for correcting the recording data corresponding to each nozzle,
A control step of controlling the driving of each nozzle based on the result of correcting the recording data corresponding to each nozzle according to the correction information,
In the calculating step, based on the shift amount corresponding to each of the plurality of nozzles, an area where a dot formed by an ink droplet ejected from a nozzle corresponding to a predetermined dot position lands on the predetermined dot position; An ink jet recording method comprising: obtaining an area where dots formed by ink droplets ejected from the nozzles land on the predetermined dot position, and setting the ratio to affect the density of the predetermined dot position . 5. The ink jet recording method according to claim 4 , wherein in the nozzle information creating step, the size of the ink dots formed by the ink droplets that have landed on the recording medium is further obtained as nozzle information representing the ejection characteristics of the nozzles. . In the correction step, in recording the image to be formed,
6. The ink jet recording method according to claim 4, wherein correction information for correcting a discharge state of a nozzle that cannot obtain an ideal landing state is created based on a calculation result of the calculation step .

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