JP4477293B2 - Photosensitive member sensitivity distribution measuring apparatus and photosensitive member sensitivity distribution measuring method - Google Patents

Description

【０１１４】
Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７は、画像記憶部４に記憶された画像データに基づいて、閾値を超える光学情報を有する画素が直線状に連続するノイズデータを画像データ中から除去するノイズ除去処理を行う。以降、ノイズデータのうち、Ｘ方向（主走査方向）に方向性を有するノイズをＸ方向ノイズ、および、Ｙ方向（副走査方向）に方向性を有するノイズをＹ方向ノイズとする。Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７の構造およびＹ方向ノイズ除去部６およびＸ方向ノイズ除去部７で実行する各ノイズ除去処理については後述するが、該ノイズ除去処理には演算パラメータが必要であり、本実施の形態では、Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７に接続されたパラメータ記憶部８に保存されている演算パラメータを用いる。パラメータ記憶部８に保存される演算パラメータとしては、各画素の光学情報の閾値や、後述する各種ノイズ除去処理での平均値の算出に関わる画素数ｉ等がある。
【０１１５】
Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７においてＸ方向ノイズおよびＹ方向ノイズが除去された画像データは、処理後画像記憶部９に記憶される。
【０１１６】
処理後画像記憶部９は、Ｘ方向ノイズおよびＹ方向ノイズを除去した画像データを実際に記憶する記憶媒体と、該記憶媒体に対して画像データを記憶させる書き込み装置（いずれも図示せず）とを備えている。処理後画像記憶部９では、例えば、ハードディスクやフレキシブルディスク、ＣＤ−Ｒ等を記憶媒体として用いることが可能である。
【０１１７】
画像表示部１０は、処理後画像記憶部９に記憶された画像データの光学情報に基づいて、ノイズ除去後の感光体の感度を反映する画像を表示する。この画像表示部１０は、例えば、ＣＲＴ、液晶モニタ等によって実現することが可能である。本実施の形態では、感光体の感度を反映する画像として、ノイズ除去後の画像データの光学情報に基づいて、帯電、露光後の感光体表面の帯電電荷量あるいは電界強度を濃淡によって示す画像を画像表示部１０に表示する。
【０１１８】
なお、本実施の形態では、処理後画像記憶部９に記憶されたノイズ除去後の画像データに基づく画像を画像表示部１０に表示させるようにしたが、これに限るものではなく、ノイズ除去後の画像を処理後画像記憶部９を介さずに画像表示部１０に直接表示させるようにしてもよい。
【０１１９】
次に、Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７の構成、および、Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７で実行するノイズ除去処理について図３ないし図１０を参照して説明する。
【０１２０】
上述したように、電子写真方式を用いた画像形成に際しては、例えば、Ｘ方向に方向性を有するノイズ（Ｘ方向ノイズ）や、Ｙ方向に方向性を有するノイズ（Ｙ方向ノイズ）等の直線状のノイズが静電潜像中に発生することがある。この直線状のノイズの発生によって、該静電潜像を顕像化した画像中には、感光体の感度ムラに起因せず、閾値を超える光学情報が直線状に連続する縦スジや横スジ等の画像構造Ｎｙ，Ｎｘ（図３，図７参照）が重畳されてしまう。本実施の形態では、Ｙ方向ノイズに起因して発生する画像構造Ｎｙを縦スジとし、Ｘ方向ノイズに起因して発生する画像構造Ｎｘを横スジとする。なお、本実施の形態では、入力装置２により取得した画像データ中で、縦スジＮｙおよび横スジＮｘ部分の画像データがノイズデータである。
【０１２１】
Ｙ方向ノイズ除去部６およびＸ方向ノイズ除去部７は、以下に説明するノイズ除去処理を行うことにより、画像中に発生した縦スジＮｙや横スジＮｘ等を除去する。
【０１２２】
なお、本実施の形態のノイズ除去処理は、方向性を有するノイズの発生方向が既知である場合に有効となる。このため、ノイズ除去処理に先立って、ノイズの発生方向を解析するノイズ方向解析処理を行う。このノイズ方向解析処理によって、ノイズ方向判断手段およびノイズ方向判断ステップとしての機能が実現される。
【０１２３】
一般的に、ノイズの方向は、上述のように、光書き込みの主走査方向あるいは副走査方向に相当する方向であることがほとんどであるので、本実施の形態では、ノイズ除去処理を、ノイズの方向を光書き込みの主走査方向あるいは副走査方向に固定して行っても構わない。
【０１２４】
また、本実施の形態では、ノイズ方向解析処理によって、方向数判断手段および方向数判定ステップとしての機能が実現される。
【０１２５】
なお、ノイズ方向の解析については、公知の画像解析技術を用いて容易に実現することが可能であるため、ここでは説明を省略し、ノイズ方向解析処理が終了し、ノイズの発生方向が既知であるものとして説明する。例えば、画像情報からノイズのみを抽出し、抽出した情報に基づいてノイズの方向を決定することも可能である。
【０１２６】
まず、図３に示すように、感光体４８を均一に帯電、露光、現像し、紙に転写、定着を行うことによって形成したわずかな濃淡変化を有する画像１１中に、Ｙ方向ノイズに起因する縦スジＮｙが重畳している場合に、Ｙ方向ノイズ除去部６によって、画像１１から縦スジＮｙを除去するノイズ除去処理について図４ないし図６を参照して説明する。
【０１２７】
ここで、図４はＹ方向ノイズ除去部６の構成を示すブロック図であり、図５はＹ方向ノイズ除去部６が実行するノイズ除去処理について概略的に説明するフローチャートである。Ｙ方向ノイズ除去部６が実行するノイズ除去処理では、まず、画像記憶部４に記憶されている画像データを、補正前画像データ記憶部１２にコピーする（ステップＳ１）。
【０１２８】
画像平均値算出部１３は、補正前画像データ記憶部１２にコピーされた画像データに基づいて、全画素の光学情報の平均値Ｐaveを取得する（Ｓ２）。本実施の形態の画像平均値算出部１３は、平均値算出部５で算出された全画素の光学情報の平均値Ｐaveを読み出し、この値を全画素の光学情報の平均値Ｐaveとして取得する。なお、平均値Ｐaveを予めパラメータ記憶部８に記憶しておき、ノイズ除去処理に際しては、パラメータ記憶部８に記憶された平均値Ｐaveを読み出すようにしてもよい。
【０１２９】
次に、補正前画像データ記憶部１２に記憶された画像データから、注目画素決定部１４により、図６中Ｐ（ｘ，ｙ）（ただし、ｘ＝１〜Ｎ，ｙ＝１〜Ｍ、（Ｎ，Ｍは正の整数））で示す任意の画素を注目画素Ｐ（ｘ，ｙ)として決定する(Ｓ３)。本実施の形態では、ステップＳ４で、注目画素Ｐ（ｘ，ｙ）のｘ、ｙをそれぞれｘ＝１，ｙ＝１に設定する。なお、注目画素Ｐ（ｘ，ｙ）は、感光体表面の顕像化領域を１００ｍｍ^２以下の単位で分割した単位毎に一点ずつ設定されるように決定する。このとき、感光体表面の顕像化領域は、５０ｍｍ^２以下に分割することが好ましく、０.０１〜２５ｍｍ^２に分割することがより好ましい。
【０１３０】
そして、周辺画素平均値算出部１５によって以下に示す（２）式の演算を行うことにより、この注目画素Ｐ（ｘ，ｙ）を含みＹ方向に沿って２ｎ＋１画素の光学情報の平均値Ｐave（ｘ，ｙ）を算出する（Ｓ５）。ここに、平均値取得手段および平均値取得ステップとしての機能が実行される。このとき、平均値Ｐave（ｘ，ｙ）を算出するための画素数２ｎ＋１の“ｎ”は、パラメータ記憶部８に記憶されている平均値の算出に関わる画素数ｉより取得する。
【０１３１】
【数２】

【０１３２】
続いて、注目画素補正部１６において、ステップＳ５で算出した平均値Ｐave（ｘ，ｙ）および平均値算出部５で算出した画像全体の画素の光学情報の平均値Ｐaveを用いて、注目画素Ｐ（ｘ，ｙ）の光学情報に対し、以下に示す（３）式の演算を施してＰ'(ｘ，ｙ)を取得する(Ｓ６)。ここに、ノイズ除去手段およびノイズ除去ステップとしての機能が実行される。
【０１３３】
【数３】

【０１３４】
これにより、注目画素Ｐ（ｘ，ｙ）の光学情報から、注目画素Ｐ（ｘ，ｙ）を中心としてＹ方向に±ｎ画素の範囲における光学情報の平均値Ｐave（ｘ，ｙ）が閾値として減算され、感光体の感度ムラに起因しないノイズによって発生する縦スジＮｙを除去した光学情報を有する画素Ｐ'（ｘ，ｙ）を取得することができる。
【０１３５】
本実施の形態の感光体感度測定装置１では、縦スジＮｙの連続方向に沿って画像データ中の任意の注目画素Ｐ（ｘ，ｙ）を含む複数（本実施の形態では２ｎ＋１個）の画素の光学情報を平均化した平均値を閾値とすることで、予め設定した既定値を閾値とする場合と比較して、縦スジＮｙを除去する対象となる画像データに適した閾値を設定することができる。
【０１３６】
なお、本実施の形態では、注目画素Ｐ（ｘ，ｙ）を中心としてＹ方向に±ｎ画素の範囲における画素の光学情報の平均値Ｐave（ｘ，ｙ）を算出しているが、これに限るものではなく、注目画素Ｐ（ｘ，ｙ）を通るＹ方向のｋ個の画素（ｋは整数）の光学情報平均値を算出すればよい。このとき、注目画素Ｐ（ｘ，ｙ）は、Ｙ方向において平均を算出する範囲内の中心にある必要はない。
【０１３７】
しかしながら、Ｙ方向ノイズＮｙの除去精度を確保するためには、注目画素Ｐ（ｘ，ｙ）が平均を算出する範囲内の中心にあることが好ましい。
【０１３８】
また、本実施の形態では、処理後の画像の平均濃度を処理前の画像とほぼ等しくするために、（３）式に示すように、画像全体の画素の光学情報の平均値Ｐaveを加算するようにしたが、これに限るものではなく、ノイズ除去後の画像データの濃淡変動のみが必要な場合には、必ずしもＰaveを加算する必要はなく、Ｐaveの代わりに任意の値を加算するようにしてもよい。このような場合にも、Ｐaveの代わりとなる任意の値をパラメータ記憶部８に記憶しておくことで、処理を効率的に行うことができる。
【０１３９】
また、本実施の形態では、平均化を行う注目画素Ｐ（ｘ，ｙ）を含みＹ方向に沿った画素数ｋの大きさを限定するものではないが、画素数ｋは小さすぎても大きすぎても十分なノイズ除去は行えないため、画素数ｋは、注目画素Ｐ（ｘ，ｙ）に対して高い相関が得られる範囲に設定する必要がある。
【０１４０】
そして、得られたＰ'（ｘ，ｙ）の光学情報をこの画素の座標に対応付けて補正後画像データ記憶部１７に記憶するとともに(Ｓ７）、注目画素Ｐ（ｘ，ｙ）におけるｘに１を加算し（Ｓ８）、処理終了判断部１８よって、ｘ＋１で示されるｘがＮより大きくなったと判断されるまで、ステップＳ５からＳ８の処理を繰り返す(Ｓ９のＮ)。
【０１４１】
処理終了判断部１８が、ｘ＋１で示されるｘがＮより大きくなったと判断した場合には（Ｓ９のＹ）、ｙに１を加算し（Ｓ１０)、処理終了判断部１８によって、ｙ＋１で示されるｙがＭより大きくなったと判断される（Ｓ１１のＹ）まで、ステップＳ５からＳ１０の処理を繰り返す（Ｓ１１のＮ)。
【０１４２】
なお、本発明は両端における処理を規定するものではないため、Ｐave（ｘ，ｙ）の演算において、ｙ＜０またはｙ＞Ｍとなる場合、Ｐave（ｘ，ｙ）＝０としても良いし、Ｐave（ｘ，ｙ）＝Ｐave（ｘ，０)またはＰave(ｘ，Ｍ)としてもよい。この場合のパラメータＭも、パラメータ記憶部８に記憶されている。
【０１４３】
これにより、処理を行う対象画像中の任意の注目画素Ｐ（ｘ，ｙ）を、対象画像の全画素に対して設定し、対象画像中の全画素の光学情報から縦スジＮｙを除去することができ、ノイズ除去処理を行うことによって縦スジ部分の画像データとそれ以外の画像データとの間に格差が発生することを抑制することができる。
【０１４４】
このとき、本実施の形態の感光体感度測定装置１では、注目画素Ｐ（ｘ，ｙ）を感光体の画像形成域全面を１００ｍｍ^２以下の単位に分割した単位毎に一点設定されるように決定するため、高解像度の画像形成装置への搭載を目的とする感光体の感度分布を高密度に測定することができる。
【０１４５】
なお、画像データ中におけるノイズ方向が一方向である場合には、縦スジＮｙを除去した画像データを処理後画像記憶部９に記憶する。処理後画像記憶部９は、画像データを構成する各画素の光学情報から縦スジＮｙを除去した後の光学情報を、各画素位置を特定する座標情報に対応付けて記憶する。
【０１４６】
次に、図７に示すように、感度分布の測定対象となる感光体４８を用いて、この感光体４８を均一に帯電、露光および現像し、用紙に転写、定着を行うことにより形成した画像に、感光体４８の感度ムラに起因する画像Ｓ以外に、Ｙ方向ノイズに起因する縦スジＮｙおよびＸ方向ノイズに起因する横スジＮｘが重畳している場合に、この画像から縦スジＮｙおよび横スジＮｘを除去するノイズ除去処理について図８および図９を参照して説明する。
【０１４７】
感度分布の測定対象となる感光体４８を用いて、この感光体４８を均一に帯電、露光および現像し、用紙に転写、定着を行うことにより形成した画像に、Ｙ方向ノイズに起因する縦スジＮｙおよびＸ方向ノイズに起因する横スジＮｘが重畳している場合には、上述したように縦スジＮｙの除去を行い、縦スジＮｙの除去を行った後の画像データに対して、Ｘ方向ノイズ除去部７によって、以下に説明するＸ方向ノイズ除去処理を実行する。なお、縦スジＮｙの除去については説明を省略するが、この場合、図５のステップＳ５によって第一の平均値取得手段および第一の平均値取得ステップとしての機能が実行され、ステップＳ６によって減算手段および減算ステップとしての機能が実行される。
【０１４８】
ここで、図８はＸ方向ノイズ除去部７の構成を示すブロック図であり、図９はＸ方向ノイズ除去部７が実行するノイズ除去処理について概略的に説明するフローチャートである。Ｘ方向ノイズ除去部７が実行するノイズ除去処理では、まず、Ｙ方向ノイズ除去部６の補正後画像データ記憶部１７に記憶されている画像データを、補正前画像データ記憶部１９に記憶する（ステップＳ２０）。
【０１４９】
画像平均値算出部２０は、補正前画像データ記憶部１９に記憶された縦スジＮｙの除去後の画像データに基づいて、全画素の光学情報の平均値Ｐaveを取得する（Ｓ２１）。本実施の形態の画像平均値算出部２０は、画像平均値算出部１３と同様に、平均値算出部５で算出された全画素の光学情報の平均値Ｐaveを読み出し、この値を全画素の光学情報の平均値Ｐaveとして取得する。
【０１５０】
次に、補正前画像データ記憶部１９に記憶された縦スジＮｙの除去後の画像データから、注目画素決定部２１により、Ｐ'（ｘ，ｙ）（ただし、ｘ＝１〜Ｎ，ｙ＝１〜Ｍ、（Ｎ，Ｍは正の整数））で示す任意の画素を注目画素Ｐ'（ｘ，ｙ)として決定する(Ｓ２２)。本実施の形態では、ステップＳ２３で、注目画素Ｐ'（ｘ，ｙ）のｘ、ｙをそれぞれｘ＝１，ｙ＝１に設定する。
【０１５１】
そして、周辺画素平均値算出部２２によって以下に示す（４）式の演算を行うことにより、この注目画素Ｐ'（ｘ，ｙ）を含みＸ方向に沿って２ｎ＋１画素の光学情報の平均値Ｐ'ave（ｘ，ｙ）を算出する（Ｓ２４）。ここに、第二の平均値取得手段および第二の平均値取得ステップとしての機能が実行される。このとき、平均値Ｐ'ave（ｘ，ｙ）を算出するための画素数２ｎ＋１の“ｎ”も、図５の処理と同様に、パラメータ記憶部８に記憶されている平均値の算出に関わる画素数ｉより取得する。
【０１５２】
【数４】

【０１５３】
続いて、注目画素補正部２３において、ステップＳ２４で算出した平均値Ｐ'ave（ｘ，ｙ）および平均値算出部５で算出した画像全体の画素の光学情報の平均値Ｐaveを用いて、注目画素Ｐ'（ｘ，ｙ）の光学情報に対して、以下に示す（５）式の演算を施すことによりＰ''(ｘ，ｙ)を取得する(Ｓ２５)。画像データ中のノイズ発生方向が複数ある場合には、ここに、ノイズ除去手段およびノイズ除去ステップとしての機能が実行される。
【０１５４】
【数５】

【０１５５】
これにより、注目画素Ｐ'（ｘ，ｙ）の光学情報から、注目画素Ｐ'（ｘ，ｙ）を中心としてＹ方向に±ｎ画素の範囲における光学情報の平均値Ｐ'ave（ｘ，ｙ）が減算され、感光体の感度ムラに起因しないＹ方向ノイズＮｙに加えて感光体の感度ムラに起因しないＸ方向ノイズＮｘを除去したＰ''(ｘ，ｙ)を取得することができる。
【０１５６】
そして、得られたＰ''（ｘ，ｙ）の光学情報をこの画素の座標に対応付けて補正後画像データ記憶部２４に記憶するとともに(Ｓ２６)、注目画素Ｐ'（ｘ，ｙ）におけるｘに１を加算し（Ｓ２７)、処理終了判断部２５によって、ｘ＋１で示されるｘがＮより大きくなったと判断されるまで、ステップＳ２４からＳ２７の処理を繰り返す(Ｓ２８のＮ)。
【０１５７】
処理終了判断部２５が、ｘ＋１で示されるｘがＮより大きくなったと判断した場合には（Ｓ２８のＹ）、ｙに１を加算し（Ｓ２９)、処理終了判断部２５によって、ｙ＋１で示されるｙがＭより大きくなったと判断される（Ｓ３０のＹ）まで、ステップＳ２４からＳ２９の処理を繰り返す（Ｓ３０のＮ)。
【０１５８】
なお、本発明は両端における処理を規定するものではないため、Ｐave（ｘ，ｙ）の演算において、ｘ＜０またはｙ＞Ｎとなる場合、Ｐave（ｘ，ｙ）＝０としても良いし、Ｐave（ｘ，ｙ）＝Ｐave（０，ｙ)またはＰave(Ｎ，ｙ)としてもよい。この場合のパラメータＮも、パラメータ記憶部８に記憶されている。
【０１５９】
これにより、ノイズの発生方向が、Ｙ方向およびＸ方向の複数方向である場合にも、感光体の表面状態に起因せず方向性を有するノイズＮｘ，Ｎｙを各連続方向において効果的に除去することができる。
【０１６０】
また、本実施の形態の感光体感度測定装置１では、縦スジＮｙの連続方向に沿って画像データ中の任意の注目画素Ｐ（ｘ，ｙ）を含む複数（本実施の形態では２ｎ＋１個)の画素の光学情報を平均化した平均値を閾値とするとともに、横スジＮｘの連続方向に沿って画像データ中の任意の注目画素Ｐ'（ｘ，ｙ）を含む複数（本実施の形態では２ｎ＋１個)の画素の光学情報を平均化した平均値を閾値とすることで、縦スジＮｙおよび横スジＮｘを除去する対象となる画像データに適した閾値を設定するとともに、全画素の光学情報からこの閾値を減算することにより、ノイズ除去処理を行うことによって縦スジＮｙおよび横スジＮｘ部分の画像データとそれ以外の画像データとの間に格差が発生することを抑制することができる。
【０１６１】
縦スジＮｙおよび横スジＮｘを除去した画像データは、処理後画像記憶部９に記憶される。処理後画像記憶部９は、画像データを構成する各画素の縦スジＮｙおよび横スジＮｘを除去した後の光学情報を、各画素位置を特定する座標情報に対応付けて記憶する。
【０１６２】
次に、画像表示部１０について説明する。画像表示部１０は、上述したように、処理後画像記憶部９に記憶されて縦スジＮｙまたは縦スジＮｙと横スジＮｘとを除去した画像データの光学情報に基づいて、光学情報の大小を帯電電荷量の大小または電界強度の強弱に変換した画像を感光体４８の感度として表示する。ここに、感度取得手段および感度取得ステップとしての機能が実現される。
【０１６３】
本実施の形態によれば、一定の光量の書き込み光を感光体の画像形成域全面に亘って一様に露光して顕像化した画像から、直線状の方向性を有するノイズ画像のみを容易に除去することができる。これによって、測定を繰返し行ったり感光体を損傷させたりすることなく、感光体４８の感度ムラに起因するわずかな濃淡を有する画像Ｓ、すなわち、感光体４８の感度分布のみを反映する画像を画像表示部１０に表示させることができる。感光体４８の感度ムラに起因する画像Ｓは、ノイズ成分に隠れがちであるが、本実施の形態のように縦スジおよび横スジを除去することにより、感光体４８の感度ムラに起因する画像Ｓのみを画像表示部１０に表示させることができるので、オペレーターは、画像表示部１０に表示された画像のわずかな濃淡に基づいて感光体４８の感度分布状態を判断することで、ノイズに影響されることなく感光体４８の感度ムラの良否を判定することができる。
【０１６４】
なお、画像表示部１０に表示される感光体４８の帯電電荷量あるいは電界強度と露光量との間には線形関係がないため、上述したノイズ除去処理は、中間調付近の画像を複数段階に調整した各露光量で露光することで形成した複数の画像に対して行う。
【０１６５】
また、本実施の形態では、Ｘ方向ノイズに起因する横スジＮｘおよびＹ方向ノイズに起因する縦スジＮｙを除去するノイズ除去処理について説明を行ったが、これに限定されるものではなく、直線状に方向性を有するノイズであれば斜め方向のノイズに対しても同様に除去することが可能である。静電潜像中に斜め方向に方向性を有するノイズが発生している場合、該静電潜像を顕像化した画像データに対して回転処理を施して、発生している異常画像構造の方向性がＸ方向またはＹ方向となるように調整することにより、いずれの方向性を有するノイズであっても該ノイズが直線状の方向性を有しているならばこれを除去することができる。なお、画像データに対する回転処理については公知の画像処理技術を用いて容易に実現することが可能であり、ここでは説明を省略する。
【０１６６】
さらに、本実施の形態では、表面感度の測定対象となる感光体４８を用いて用紙上に形成した画像を光学的に読み取る入力装置２を用いた場合について説明したが、感光体上に形成されて用紙に転写する以前のトナー像を光学的に読み取ることで画像データを取得するようにした場合、用紙上に形成した画像から画像データを取得する場合と比較して、転写工程や定着工程を含まない分、転写工程や定着工程に際して発生するノイズを含まない画像データを得ることが可能になるので、感光体４８の感度分布をより高精度に測定することができる。
【０１６７】
加えて、本実施の形態では、帯電電荷量の大小あるいは電界強度の強弱を濃淡で示す画像によって感光体４８の感度分布を反映するようにしたが、これに限るものではなく、感光体４８の感度と感光層４８ｂの膜厚との関係を予め実験等によって取得しておき、取得した感度と膜厚との関係を図示しない記憶装置に記憶させておくことで、ノイズ除去処理後の画像データの光学情報に基づいて取得される感光体４８の感度分布に代えて、帯電電荷量の大小あるいは電界強度の強弱を濃淡で示す画像によって感光層４８ｂの膜厚の分布状態を反映するようにしてもよい。このとき、感度と膜厚との関係を記憶する記憶装置によって膜厚記憶装置が実現され、この膜厚記憶装置に基づいて感光層４８ｂの膜厚の分布状態を反映する画像を表示する処理によって膜厚分布取得手段および膜厚分布取得ステップとしての機能が実現される。
【０１６８】
次に、本発明の第二の実施の形態について図１０を参照して説明する。なお、第一の実施の形態と同一部分は同一符号で示し、説明も省略する。
【０１６９】
図１０は、本実施の形態の感光体感度測定装置３０を示すブロック図である。本実施の形態の感光体感度測定装置３０は、処理後画像記憶部９に記憶された画像データに基づいて、対象とする感光体４８の感度分布状態が規定範囲内であるか否かを判断する感度差判断部３１を備えている。感度差判断部３１での判断に際しては、比較対象となる閾値が必要であり、この閾値はパラメータ記憶部８に記憶されているパラメータを用いる。感度差判断部３１での判断に際して用いる閾値は、予め実験等を行うことによって取得することができる。
【０１７０】
感度差判断部３１は、処理後画像記憶部９に記憶された画像データに基づいて取得される光学情報の最も低い画素の光学情報と、光学情報の最も高い画素の光学情報との差や、全画素の光学情報の平均値や標準偏差等の感度偏差パラメータをパラメータ記憶部８から取得される規定範囲とを比較し、感度偏差パラメータが規定範囲内である場合には良、感度偏差パラメータが規定範囲外である場合には不良である旨を画像表示部１０に表示させる。パラメータ記憶部８において感度偏差パラメータを記憶する記憶媒体としては、例えば、ハードディスク、フレキシブルディスク、ＣＤ−Ｒ、ＣＤ−ＲＷ、ＤＶＤ、ＩＣカード等を例示することができる。ここに、分布状態判断手段および分布状態判断ステップとしての機能が実現される。
【０１７１】
なお、本実施の形態の感度偏差パラメータは、画像記憶部９に記憶された画像データそのものを用いた例について示したが、これに限るものではなく、例えば、隣接する複数の画素を一つの画素として扱い、それらの画素の光学情報の平均値等を感度偏差パラメータとして用いてもよい。
【０１７２】
従来の方法のように、製造した感光体４８が使用可能かどうか判定するために、画像形成された画像中の異常画像の有無を人が判断することで感光体４８の合否を判定すると、人による判定のために個人差および朝夕の時間のバラツキが生じやすいという不具合があるが、本発明の感光分布測定方法により感度分布を測定し、測定した感度分布を判定する規定範囲を設定することにより、評価者の技能によるバラツキや画像形成装置の機器間の差による影響を排除し、感光体４８の合否の判定を適切に行うことができる。
【０１７３】
そして、上述した分布状態判断ステップにおいて、不良と判断された場合には、感光体４８の製造方法に感度分布をフィードバックする。例えば、感度が全体と著しく異なる箇所が点状の場合には、バイトの交換、バイトの送り速度、感光体４８の基体４８ａの回転速度、潤滑液の供給速度等の感光体４８の基体４８ａの作製条件、塗工液中の異物除去等の感光層４８ｂの塗工条件、あるいは、温度、湿度、ダスト濃度、気流の強さと方向等の塗工雰囲気の環境を予め決められた優先順位にしたがって適切な状態に調整する。また、例えば、感度が全体と著しく異なる箇所が斑点状の場合には、感光層４８ｂの塗工条件や塗工雰囲気の環境を予め決められた優先順位にしたがって適切な状態に調整する。これにより、感光体４８の製造方法を適切に改善することができる。
【０１７４】
【実施例】
次に、本発明の実施例について以下に説明する。実施例では、以下に説明するようにして複数の感光体４８を実際に作製し、作製した感光体４８に対して上述したノイズ除去処理を施すことによって得られたデータに基づいて、作製した感光体４８の品質を比較した。
【０１７５】
まず、下記組成の混合物をボールミルポットにとり、φ１０ｍｍアルミナボールを使用して７２時間ボールミリングした。
酸化チタン（ＣＲ−６０：石原産業製）：５０.０重量部
アルキッド樹脂（ベッコライトＭ６４０１−５０：大日本インキ化学工業製）：１５.０重量部
メラミン樹脂（スーパーベッカミンＬ−１２１−６０：大日本インキ化学工業製）１０.０重量部
メチルエチルケトン（関東化学製）：３１.７重量部
【０１７６】
このミリング液に対して、シクロヘキサノン（関東化学製）：１０５.０重量部を加え、さらに２時間ボールミリングして下引き層用塗布液を作製した。
【０１７７】
この下引き層用塗布液中に周長２９０.３ｍｍ、厚さ３０μｍのニッケルシームレスベルト（ビッカース硬度４８０〜５１０、純度９９.２％以上）を浸漬させ、ニッケルシームレスベルトに対して下引き層用塗布液を浸漬塗工し、１３５℃で２５分間乾燥して、膜厚６.５μｍの下引き層を形成した。
【０１７８】
続いて、下記組成の混合物をボールミルポットにとり、φ１０ｍｍ瑪瑙ボールを使用し時間ボールミリングした。
以下に（化１）で示す化学式構造を有する電荷発生物質（リコー製）：１.５重量部
【化１】

以下に（化２）で示す化学式構造を有する電荷発生物質（リコー製）：１.５重量部
【化２】

ポリビニルブチラール樹脂（エスレックＢＬＳ：積水化学製）：１.０部
シクロヘキサノン（関東化学製）：８０.０重量部
【０１７９】
このミリング液に対して、さらにシクロヘキサノン７８.４部とメチルエチルケトン２３７.６重量部とを加えて調整した電荷発生層塗布液を作製した。この電荷発生層塗布液に対して、上述の下引層を積層したニッケルシームレスベルトを浸漬させ、下引層を積層したニッケルシームレスベルトに対して電荷発生層塗布液を浸漬塗工し、１３０℃で２０分間乾燥し、厚さ０.１２μｍの電荷発生層を形成した。
【０１８０】
次に、下記組成の電荷輸送層塗工液を調整した。
以下に（化３）で示す化学式構造を有する電荷輸送物質（リコー製）：７重量部
【化３】

ポリカーボネート樹脂（Ｃ−１４００：帝人化成製）：１０重量部
シリコーンオイル（ＫＦ−５０：信越化学製）：０.００２重量部
テトラヒドロフラン（関東化学製）：８４１.５重量部
シクロヘキサノン（関東化学製）：８４１.５重量部
３−ｔ−ブチル−４−ヒドロキシアニソール（東京化成製）：０.０４重量部
【０１８１】
上述した電荷輸送層塗工液を、下引層、電荷発生層を積層したニッケルシームレスベルトを回転させながらスプレー塗工した後、１４０℃で３０分間乾燥して、厚さ約２５μｍの電荷輸送層を形成して感光体４８を作製した。
【０１８２】
上述のような作製方法により作製される感光体４８のスプレー塗工条件を５種類に変化させて作製した５本の感光体をそれぞれ幅３６７ｍｍに切断し、切断した感光体４８の任意の位置２０点の膜厚を、触針式の膜厚計で測定した。この測定結果に基づいて、（膜厚の最大値−膜厚の最小値）によって取得される値を膜厚のムラとして求めたところ、作製した各感光体４８の膜厚ムラはそれぞれ、０.９μｍ、１.２μｍ、１.８μｍ、２.５μｍ、３.０μｍであった。
【０１８３】
続いて、厚さ０.８ｍｍ、ゴム硬度７０のウレタンゴム上に厚さ約４０μｍのアクリル系粘着剤を積層し、さらに剥離紙を積層した。これを幅４ｍｍ、長さ２８５ｍｍの長さにトムソン刃で打ち抜き寄り止めガイドとした。
【０１８４】
感光体４８の導電性支持体４８ａ（基体）の端部から５ｍｍの両側縁内面に、上記の寄り止ガイドを剥離紙を剥しながら貼り付け固定し感光体を作製した。
【０１８５】
このように作製した感光体４８をＩＰＳｉＯ Ｃｏｌｏｒ ５０００改造機（リコー製）に搭載し画像形成装置を作製した。パソコンで全面グレーの画像を作成し、帯電電圧−８００Ｖ、露光量０.３μＪ／ｃｍ^２で白黒モード、１２００ｄｐｉ、２×２ドットで画像形成を行った。
【０１８６】
このとき用いたＩＰＳｉＯ Ｃｏｌｏｒ ５０００改造機は完成品ではなかったため、感光体４８に起因しない多くの横スジ、縦スジが存在した。
【０１８７】
画像形成した画像を明度リニアな入力特性を持つスキャナにより１００ｄｐｉの解像度でパソコンに電子情報として取り込んだ。取り込んだ画像情報から感光体４８の周方向の長さ２９０.３ｍｍ部分のみをトリミングした。
【０１８８】
この画像データに対して上述した第一の実施の形態と同様にＸ方向およびＹ方向のノイズＮｘ，Ｎｙを除去し、ノイズ除去後の画像を１０×１０画素のフィルタサイズで平滑化を行い、ノイズ除去画像を得た。その結果、ノイズ除去処理前の画像には図２または図６に示すように直線状のノイズが発生していたのに対し、ノイズ除去処理後の画像１１’は図１０に示すように感光体４８の感度ムラに起因する画像Ｓのみ、すなわち、感度分布のみを反映していることが判る。なお、ここでは、膜厚ムラが２.５μｍの感光体を用いて形成した画像について説明する。
【０１８９】
ところで、露光量０.３μＪ／ｃｍ^２では、画像濃度（ＩＤ）と感光体の電界強度（Ｅ：Ｖ／μｍ）との間には、以下に（６）式で示す関係が存在する。
Ｅ＝−２０.１×（１.１９−ＩＤ） …（６）
【０１９０】
画像データは、画像の各座標（感光体表面の各座標）毎に光学情報を有しているため、（６）式によれば、露光量０.３μＪ／ｃｍ^２での、各座標における感光体の電界強度を求めることができる。
【０１９１】
ここで、画像形成域中での電界強度のバラツキの許容範囲を決定付ける規定範囲を０.３５Ｖ／μｍに設定したところ、感光体の膜厚ムラが０.９μｍ、１.２μｍのものは合格で、その他の感光体４８は不合格と判定することができた。
【０１９２】
なお、実施例においては、顕像化された画像における画素と、この画素の感光体４８上での位置との整合を完全にはとらなかったが、例えば、感光体４８の書き込み位置を特定する手段を設けることで、感光体４８の感度ムラが生じた原因解析に用いることができる。
【０１９３】
続いて、電界強度のバラツキが規定範囲内となる膜厚ムラ１.２μｍとなる製造条件で感光体４８を量産し、製造５０本毎に前述の感度分布の測定を行った。これによれば、感光体製造１２００本目に感度分布の閾値を超えてしまったため、量産を中止したが、その後、スプレーガンの清掃を行い製造を再開したところ、感光体製造を２８００本行っても感度分布の閾値を超える感光体４８は製造されなかった。
【０１９４】
【発明の効果】
請求項１記載の発明によれば、一様に帯電した感光体表面を一様に露光走査した静電潜像を顕像化した画像データにおいて、閾値を超える光学情報を有する画素が直線状に連続するノイズデータの光学情報から閾値を減算した後の全画素の光学情報を感光体の感度として取得することで、膜厚測定や電位測定等により感光体の感度を直接測定することによる煩雑な作業や感光体の損傷等を招くことなく顕像化領域全体に亘る感光体の感度分布を容易に測定することができる。更に、ノイズデータの連続方向に沿って画像データ中の任意の注目画素を含む複数の画素の光学情報を平均化した平均値を閾値として取得することで該画像データに適した閾値を設定するとともに、全画素の光学情報からこの閾値を減算することで、ノイズ除去を行うことによってノイズデータとそれ以外の画像データとの間に格差が発生することを抑制することができる。
請求項２記載の発明によれば、実用上、高解像度の画像形成装置での使用を対象とした感光体の感度を高密度に判定することができる。
請求項３記載の発明によれば、ノイズデータの連続方向が複数ある場合にも、各連続方向に沿って画像データ中の任意の注目画素を含む複数の画素の光学情報を平均化した平均値を閾値として取得することで該画像データに適した閾値を設定するとともに、全画素の光学情報からこの閾値を減算することで、ノイズ除去を行うことによってノイズデータとそれ以外の画像データとの間に格差が発生することを抑制することができる。
請求項４記載の発明によれば、感光体の感度ムラの原因となる膜厚ムラが発生し易い方法で形成された感光層を有する感光体であっても発明の効果を得ることができる。
請求項５記載の発明によれば、感光体の感度ムラの原因となる膜厚ムラが発生し易い方法で形成された感光層を最表層に有する感光体であっても発明の効果を得ることができる。
請求項６記載の発明によれば、感度差が規定範囲外であるか否かを正確に判断することができるので、感度差が規定範囲外である場合には、製造方法を変更する等の対応をとることで、感度差が規定範囲外の感光体を大量に生産してしまうことがない。
請求項７記載の発明によれば、記録媒体に形成されたトナー像から画像データを取得することで、画像データを取得するための機構を感光体の周囲に設ける等の構成上の制約を受けることなく、感光体の感度ムラを容易に判定することができる。
請求項８記載の発明によれば、感光体に形成されたトナー像から画像データを取得することができ、記録媒体に形成したトナー像から画像データを取得する場合と比較して、転写以降の工程を含まないため、転写工程以降の工程で発生するノイズの影響を受けない画像データを取得することができる。
請求項９記載の発明によれば、感光体の感度から感光体の顕像化領域全体における感光層の膜厚の分布状態を取得することができるので、膜厚計等を用いて膜厚を直接測定することによって感光層を損傷することがない。
請求項１０記載の発明によれば、一様に帯電した感光体表面を一様に露光走査した静電潜像を顕像化した画像データにおいて、閾値を超える光学情報を有する画素が直線状に連続するノイズデータの光学情報から閾値を減算した後の全画素の光学情報を感光体の感度として取得することで、膜厚測定や電位測定等により感光体の感度を直接測定することによる煩雑な作業や感光体の損傷等を招くことなく顕像化領域全体に亘る感光体の感度分布を容易に測定することができる。さらに、ノイズデータの連続方向に沿って画像データ中の任意の注目画素を含む複数の画素の光学情報を平均化した平均値を閾値として取得することで該画像データに適した閾値を設定するとともに、全画素の光学情報からこの閾値を減算することで、ノイズ除去を行うことによってノイズデータとそれ以外の画像データとの間に格差が発生することを抑制することができる。
請求項１１記載の発明によれば、実用上、高解像度の画像形成装置での使用を対象とした感光体の感度を高密度に判定することができる。
請求項１２記載の発明によれば、ノイズデータの連続方向が複数ある場合にも、各連続方向に沿って画像データ中の任意の注目画素を含む複数の画素の光学情報を平均化した平均値を閾値として取得することで該画像データに適した閾値を設定するとともに、全画素の光学情報からこの閾値を減算することで、ノイズ除去を行うことによってノイズデータとそれ以外の画像データとの間に格差が発生することを抑制することができる。
請求項１３記載の発明によれば、感光体の感度ムラの原因となる膜厚ムラが発生し易い方法で形成された感光層を有する感光体であっても発明の効果を得ることができる。
請求項１４記載の発明によれば、感光体の感度ムラの原因となる膜厚ムラが発生し易い方法で形成された感光層を最表層に有する感光体であっても発明の効果を得ることができる。
請求項１５記載の発明によれば、感度差が規定範囲外であるか否かを正確に判断することができるので、感度差が規定範囲外である場合には、製造方法を変更する等の対応をとることで、感度差が規定範囲外の感光体を大量に生産してしまうことがない。
請求項１６記載の発明によれば、記録媒体に形成されたトナー像から画像データを取得することで、画像データを取得するための機構を感光体の周囲に設ける等の構成上の制約を受けることなく、感光体の感度ムラを容易に判定することができる。
請求項１７記載の発明によれば、感光体に形成されたトナー像から画像データを取得することができ、記録媒体に形成したトナー像から画像データを取得する場合と比較して、転写以降の工程を含まないため、転写工程以降の工程で発生するノイズの影響を受けない画像データを取得することができる。
請求項１８記載の発明によれば、感光体の感度から感光体の顕像化領域全体における感光層の膜厚の分布状態を取得することができるので、膜厚計等を用いて膜厚を直接測定することによって感光層を損傷することがない。
【図面の簡単な説明】
【図１】本発明の第一の実施の形態の感光体感度分布測定装置の構成例を示すブロック図である。
【図２】表面感度の測定対象となる感光体を用いて用紙上に画像を形成するための画像形成装置を概略的に示す縦断側面図である。
【図３】電子写真方式を用いて形成した画像中に発生するノイズを示す説明図である。
【図４】Ｙ方向ノイズ除去部の構成を示すブロック図である。
【図５】Ｙ方向ノイズ除去部が実行するノイズ除去処理について概略的に説明するフローチャートである。
【図６】光学情報を平均化する画素を示す説明図である。
【図７】電子写真方式を用いて形成した画像中に発生するノイズを示す説明図である。
【図８】Ｘ方向ノイズ除去部の構成を示すブロック図である。
【図９】Ｘ方向ノイズ除去部が実行するノイズ除去処理について概略的に説明するフローチャートである。
【図１０】本発明の第二の実施の形態の感光体感度分布測定装置の構成例を示すブロック図である。
【図１１】実施例においてノイズ除去処理後の画像を示す説明図である。
【符号の説明】
１ 感光体感度分布測定装置
２ データ取得手段
４８ 感光体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photoreceptor sensitivity distribution measuring apparatus and a photoreceptor sensitivity distribution measuring method.
[0002]
[Prior art]
In recent years, there has been a demand for an image forming apparatus that can form an image with high resolution, high definition, and faithful to an original image. In particular, recently, there is an increasing demand for an image forming apparatus capable of forming a halftone image such as a photograph. In such image formation using a lot of halftones, the sensitivity unevenness inherent to the photoreceptor itself cannot be ignored when the resolution of the image is 1000 dpi or more, and the surface potential of the photoreceptor in the halftone range is 10 to 20V. In many cases, unevenness occurs in the formed image, resulting in a problem.
[0003]
In general, a photoreceptor is composed of a cylindrical base and a photosensitive layer laminated on the outer peripheral surface of the base. In many cases, the photosensitive layer is formed by sequentially laminating a charge generation layer, a charge transport layer, a protective layer, and the like on the substrate surface. Sensitivity unevenness of a photoreceptor having such a photosensitive layer is caused by uneven surface condition of the substrate, coating unevenness of each layer laminated on the substrate surface, and the like.
[0004]
In particular, in an image forming apparatus using coherent light such as laser light or LED light, density unevenness may occur in a visualized image due to film thickness unevenness of the photoconductor. It is necessary to detect the unevenness of sensitivity early. The density unevenness of the image due to the film thickness unevenness of the photoconductor tends to become more prominent when the resolution of the image written on the photoconductor becomes higher. Therefore, the more the photoconductor is applied to a high-resolution image forming apparatus. Therefore, it is necessary to detect the sensitivity unevenness of the photoconductor early and reliably.
[0005]
By the way, as a method for measuring the sensitivity of the photosensitive member, generally, after charging the photosensitive member, the potential of the photosensitive member when exposed to a certain amount of light is measured, or the photosensitive member is There is a method of measuring the amount of writing light irradiated until reaching a certain amount of potential. Since many photoconductors have a cylindrical shape, when using the measurement method as described above, the surface potential of the photoconductor charged and exposed while rotating around the axis is measured using a surface potentiometer or the like. A method of measuring along the circumference of the heart is common.
[0006]
At this time, if the distance between the photoconductor and the surface electrometer is not always constant, the measurement accuracy of the surface potential deteriorates. Therefore, when measuring the sensitivity of the photoconductor, the photoconductor can be rotated around the axis at a fixed position. The distance between the surface of the photoconductor and the surface electrometer is kept constant by holding the position of the surface electrometer relative to the surface of the photoconductor.
[0007]
However, if the position of the surface electrometer is fixed with respect to the surface of the photoconductor that is rotatably held around the axis at a fixed position, only a part of the sensitivity in the axial direction of the photoconductor can be measured. Since the sensitivity of the photoreceptor varies depending on the surface condition of the substrate and the lamination state of each layer of the photosensitive layer laminated on the substrate surface, it is desirable to measure over the entire visualization region related to image formation on the photoreceptor.
[0008]
In order to measure the sensitivity of the photosensitive member over the entire visualization region, for example, a method of arranging a plurality of surface electrometers along the axial direction of the photosensitive member held rotatably at a fixed position around the axial center Can be considered. According to such a method, it is possible to measure the surface potential of the photoreceptor over a wide range. However, in actuality, if surface electrometers are placed close to each other, the surface electrometers interfere with each other and cannot accurately measure the surface potential of the photoreceptor. There are physical limitations. 100mm over the entire visualization area for high image quality²Although it is necessary to measure the sensitivity of the photosensitive member in each region in the state where the region is divided into the following regions, for the reasons described above, the sensitivity distribution of the photosensitive member can be obtained only with a very rough matrix.
[0009]
In addition, in order to measure the sensitivity of the photoconductor over the entire visualized region, there is also a method of measuring the surface potential while finely changing the position of the surface electrometer relative to the photoconductor along the axial direction of the photoconductor. Conceivable. However, this method requires a great deal of labor for sensitivity measurement. In addition, since charging and exposure are performed each time the sensitivity of a photoconductor is measured, the position of the surface potentiometer with respect to the photoconductor is changed along the axial direction of the photoconductor while changing the entire imaging area. In order to measure the surface potential, charging and exposure are repeated many times, but when charging and exposure are repeated, the first measurement result and measurement are measured despite the measurement of the photosensitivity in the same region. In many cases, the electrostatic characteristics of the photosensitive member are different from the measurement result after the repetition. For this reason, it is often difficult to determine whether the photosensitive member has inherent sensitivity unevenness or sensitivity unevenness caused by repeated measurement.
[0010]
Further, there is a method of measuring the film thickness of each layer forming the photosensitive layer in order to measure the sensitivity of the photosensitive member over the entire visualization region. When measuring the film thickness of each layer forming the photosensitive layer, the film thickness is generally measured by a physical film thickness meter or an eddy current film thickness meter. However, in the method of measuring the film thickness over the entire image forming area of the photoconductor, a great deal of labor is required and the surface of the photoconductor is likely to be damaged by the measurement. For this reason, the current situation is that the measured photoconductor must be discarded.
[0011]
For this reason, there is a need for a simple method for measuring the sensitivity of the photoconductor over the entire visualization region.
[0012]
Here, the surface state of the substrate of the photosensitive member may change uniformly over the entire surface of the substrate, but hardly changes in a partial manner unless it is intentionally manufactured. Further, since the charge generation layer has absorption in the visible region, the film thickness can be determined relatively easily by visual observation. For this reason, it is relatively easy to manage the surface state of the substrate and the film thickness of the charge generation layer.
[0013]
On the other hand, since the charge transport layer and the protective layer, which are not preferable when absorbing the writing light, are generally formed of a transparent material, it is impossible to visually measure the film thickness. Assuming that the surface state of the toner and the film thickness of the charge generation layer are constant, the charge transport layer and the protective layer film are used for images that are uniformly charged and exposed, developed, transferred, and fixed uniformly. It is considered that shading unevenness due to thickness unevenness is generated, and the film thickness distribution of the photoreceptor is reflected. That is, it is considered that the sensitivity unevenness of the photoreceptor can be obtained from the density unevenness of the visualized image.
[0014]
By the way, in image formation using an electrophotographic method, generally, a one-dimensional optical writing is performed in the main scanning direction by a laser, an LED, or the like, and the photosensitive member is moved in the sub-scanning direction to the optical writing position. The two-dimensional electrostatic latent image is formed. For this reason, when the adjustment of the writing device is incomplete or the rotation control of the photoreceptor is incomplete, the two-dimensional electrostatic latent image has a linear shape along the main scanning direction or the sub-scanning direction. It becomes easy to generate noise. Such linear noise has a characteristic that it tends to become noticeable when an image having a uniform density region or a gentle gradation region is formed.
[0015]
When noise occurs in the electrostatic latent image, an abnormal image such as a horizontal stripe or a vertical stripe that is not caused by a photoconductor such as so-called banding is superimposed on an image obtained by visualizing the electrostatic latent image. There are many cases. Horizontal stripes and vertical stripes not caused by this photoconductor occur irregularly, and the image density unevenness due to noise not caused by this photoconductor often becomes equal to or higher than the image density unevenness due to the film thickness distribution of the photoconductor. It may end up. In particular, in a photoconductor intended for use in a high-resolution image forming apparatus, the density of noise not attributable to the photoconductor is less than the slight density unevenness in the image due to the photoconductor such as the film thickness distribution of the photoconductive layer. In most cases, the unevenness is much larger. For this reason, for example, even if the image density of each part of the image is measured by a Macbeth densitometer or the like, it is extremely difficult to measure the image density difference due to the film thickness unevenness of the photoreceptor.
[0016]
Ideally, such a problem caused by noise is to take measures such as sufficient maintenance of the image forming apparatus to eliminate noise in the electrostatic latent image and form an image free from density unevenness due to noise. Although it can be eliminated if possible, in reality, it is difficult to completely suppress the generation of noise. In particular, the situation in which the measurement of the film thickness distribution of the photoconductor is required is that the image forming apparatus itself is often incomplete, such as during the development of an image forming apparatus on which the photoconductor is mounted. It is difficult to avoid noise superimposition.
[0017]
For this reason, in order to determine the sensitivity unevenness of the photoconductor from the density unevenness of the visualized image, it is essential to remove the density unevenness that does not originate from the photoconductor from the formed image.
[0018]
For example, as disclosed in Japanese Patent Application Laid-Open No. 2000-2621, as a conventional technique for detecting density unevenness of an image, an image region is divided into two or more regions for the purpose of inspection of a color filter or the like. There is an “image shading unevenness detection method” in which the unevenness area is specified by comparing the difference between the density average of the area and the overall average and a threshold value set separately.
[0019]
Further, as disclosed in Japanese Patent Laid-Open No. 2001-243473, the difference between the average luminance value of the target image area and the average luminance value of the donut-shaped area set so as to surround the area is calculated and set separately. There is an “image density unevenness detection method” that detects an uneven area in comparison with a threshold value. According to the technique disclosed in the publication, it is possible to improve the detection sensitivity of point-like unevenness for the purpose of detecting unevenness of a color filter.
[0020]
In addition, a method for making noise in an image inconspicuous using a smoothing filter is well known.
[0021]
[Problems to be solved by the invention]
However, the techniques disclosed in Japanese Patent Laid-Open Nos. 2000-2621 and 2001-243473 cannot detect slight shading unevenness from an image on which noise is superimposed. It was not possible to sufficiently extract an image due to uneven thickness.
[0022]
In addition, the method of making the noise in the image less noticeable using the smoothing filter does not remove the noise but only diffuses the noise in the image to make it less noticeable. Therefore, it is difficult to obtain a detailed film thickness distribution of the photoconductor over the image forming area of the photoconductor from the image information of the image formed.
[0023]
Further, since there is no linear correlation between the charge amount or electric field intensity on the photoconductor and the exposure amount, it is impossible to measure useful sensitivity simply by measuring the density of one image.
[0024]
An object of the present invention is to easily measure the sensitivity of a photosensitive member over the entire visualized region without being affected by noise.
[0025]
[Means for Solving the Problems]
  The invention according to claim 1 is a data acquisition means.(A)And noise removal means(B)And sensitivity acquisition means(C)A photosensitive member sensitivity distribution measuring device comprising at least
  Said data acquisition means(A)
  Means for acquiring image data including optical information of each pixel constituting an image obtained by visualizing an electrostatic latent image formed by uniformly exposing and scanning the surface of a uniformly charged photosensitive memberWhen,
  Pixels having the optical information in the acquired image data areIt has directionality in the sub-scanning direction y and / or the main scanning direction x, which is not caused by the sensitivity unevenness of the photoreceptor.Continuous noise data in a straight lineIn order to remove the noise data, the noise dataNoise direction determining means for determining the continuous direction of
  The continuous direction of the noise data determined by the noise direction determination meansIs the sub-scanning direction y, the sub-scanning direction yAny pixel of interest in the image data alongP (x, y)Averaging optical information of multiple pixels includingPave (x, y)Mean value acquisition means to acquireHave
  The noise removing means(B)
  Based on the acquired image data, the average value of the optical information of all pixels is Pave,
  Using the average value Pave (x, y) acquired by the average value acquisition means from the optical information of each pixel of interest P (x, y) as a threshold value,
  P ′ (x, y) = P (x, y) −Pave (x, y) + Pave
By
  Noise removing means (B) for subtracting the threshold value from optical information of noise data in which pixels having optical information are linearly continuous;
  The sensitivity acquisition means(C)
  The noise removing means(B)Sensitivity acquisition means for acquiring optical information of all pixels after subtracting the threshold as the sensitivity of the photosensitive member(C)This is a photosensitive member sensitivity distribution measuring apparatus.
  The invention according to claim 2The target pixel P (x, y)The visible area on the surface of the photoreceptor is 100 mm²One point is set for each unit divided by the following unitsBe doneThe photoconductor sensitivity distribution measuring apparatus according to claim 1.
  The invention described in claim 3The noise direction determination meansDirection number determination means for determining whether there are a plurality of continuous directions of the noise data determined by
  When the number-of-directions determination unit determines that there are a plurality of continuous directions of the noise data, an arbitrary target pixel in the image data is selected along one continuous direction of the noise data determined by the noise direction determination unit. A first average value acquisition means for averaging the optical information of a plurality of pixels including to acquire a first average value;
  Subtracting means for subtracting the first average value acquired by the first average value acquisition means from the optical information of each target pixel, with all the pixels in the image data as the target pixel,
  The optical after the subtraction means subtracts the first average value from a plurality of pixels including any target pixel in the image data along another continuous direction of the noise data determined by the noise direction determination means A second average value acquisition means for averaging information and acquiring a second average value;
  The noise removing means(B)2. All pixels in the image data are used as the target pixel, and the second average value acquired by the second average value acquisition unit is subtracted from the optical information of each target pixel as the threshold value. Or the photosensitive member sensitivity distribution measuring apparatus according to 2Is.
  According to a fourth aspect of the present invention, the photosensitive member has a photosensitive layer in which a plurality of layers, at least one layer of which is formed using a spray coating method, are laminated on a substrate surface.Or3. Photosensitive body sensitivity distribution measuring apparatus according to item 3Is.
  According to a fifth aspect of the present invention, there is provided the photosensitive member sensitivity distribution measuring apparatus according to the first, second or third aspect, wherein the photosensitive member has a photosensitive layer which is laminated on a substrate surface and the outermost layer is formed by using a spray coating method. It is.
  The invention according to claim 6 is the sensitivity acquisition means.(C)A distribution state determination unit that determines whether or not the sensitivity difference in the entire visualized region of the photoconductor is outside a specified range based on the sensitivity of the photoconductor acquired by the image forming apparatus. 3, 4Or5. The photosensitive member sensitivity distribution measuring apparatus according to 5.
  The invention according to claim 7 is the data acquisition means.(A)The image data of an image in which an electrostatic latent image is visualized by transferring the toner attached to the surface of the photosensitive member to a recording medium is acquired.Or6. The photosensitive member sensitivity distribution measuring apparatus according to 6.
  The invention according to claim 8 is the data acquisition means.(A)The image data of an image obtained by visualizing an electrostatic latent image by attaching toner to the surface of the photoconductor is acquired.Or6. The photosensitive member sensitivity distribution measuring apparatus according to 6.
  The invention according to claim 9 is a film thickness storage device that stores the sensitivity of the photoconductor and the film thickness of the photosensitive layer in association with each other in a storage area;
The sensitivity acquisition means with reference to the storage area(C)A film thickness distribution acquisition means for acquiring a distribution state of the film thickness of the photosensitive layer in the entire visualized region of the photoconductor based on the sensitivity of the photoconductor acquired by:
  Claims 1, 2, 3, 4, 5, 6, 7Or8. The photoconductor sensitivity measuring device according to 8.
  The invention according to claim 10 is the data acquisition step.(D)And noise removal step(E)And sensitivity acquisition step(F)A photoreceptor sensitivity distribution measuring method comprising at least
  The data acquisition step(D),
  A step of acquiring image data including optical information of each pixel constituting an image obtained by visualizing an electrostatic latent image formed by uniformly exposing and scanning a uniformly charged photoconductor surface.When,
  Pixels having the optical information in the acquired image data areIt has directionality in the sub-scanning direction y and / or the main scanning direction x, which is not caused by the sensitivity unevenness of the photoreceptor.Continuous noise data in a straight lineIn order to remove the noise data, the noise dataNoise direction determination step for determining the continuous direction of
  The continuous direction of the noise data determined by the noise direction determination stepIs the sub-scanning direction y, the sub-scanning direction yAny pixel of interest in the image data alongP (x, y)Averaging optical information of multiple pixels includingPave (x, y)And the average value acquisition stepHave,
  The noise removing step(E),
Based on the acquired image data, the average value of the optical information of all pixels is Pave,
  Using the average value Pave (x, y) acquired by the average value acquisition means from the optical information of each pixel of interest P (x, y) as a threshold value,
  P ′ (x, y) = P (x, y) −Pave (x, y) + Pave
By
  A noise removal step (E) in which the threshold value is subtracted from optical information of noise data in which pixels having optical information are linearly continuous;
  The sensitivity acquisition step(F),
The noise removing step(E)A sensitivity acquisition step of acquiring the optical information of all the pixels after subtracting the threshold as the sensitivity of the photoconductor(F)This is a method of measuring the sensitivity distribution of a photoreceptor.
  The invention according to claim 11The target pixel P (x, y)The visible area on the surface of the photoreceptor is 100 mm²One point is set for each unit divided by the following unitsThe claim of claim 10This is a photoreceptor sensitivity distribution measuring method.
  The invention according to claim 12The noise direction determination step includesA direction number determining step for determining whether or not the determined continuous direction of the noise data is plural;
  When it is determined that there are a plurality of continuous directions of the noise data, the optical information of a plurality of pixels including an arbitrary pixel of interest in the image data is averaged along one continuous direction of the determined noise data. A first average value acquisition step of acquiring one average value;
  Subtracting the first average value from the optical information of each pixel of interest, with all pixels in the image data as the pixel of interest,
The second average value is obtained by averaging the optical information after subtracting the first average value of a plurality of pixels including any target pixel in the image data along another continuous direction of the determined noise data. A second average value acquisition step of acquiring
ThePossess,
  The noise removing step(E)The photosensitivity distribution measurement method according to claim 10 or 11, wherein all pixels in the image data are used as the target pixel, and the second average value is subtracted from the optical information of each target pixel as the threshold value. is there.
  A thirteenth aspect of the present invention is directed to the photoconductor having a photosensitive layer in which a plurality of layers, at least one layer of which is formed using a spray coating method, are laminated on a substrate surface.Or12. The photosensitive member sensitivity distribution measuring method according to 12.
  A fourteenth aspect of the present invention is directed to the photosensitive member sensitivity according to the tenth, eleventh, twelfth or thirteenth aspect, wherein the outermost layer is a photosensitive layer formed using a spray coating method and is laminated on the surface of the substrate. This is a distribution measurement method.
  According to a fifteenth aspect of the present invention, there is provided a distribution state determination step of determining whether or not the sensitivity difference in the entire visualized region of the photoconductor is outside a specified range based on the acquired sensitivity of the photoconductor. Claims 10, 11, 12, 13Or 14It is a photoreceptor sensitivity distribution measuring method as described.
  The invention according to claim 16In the step of acquiring the image data in the data acquisition step (D), when the electrostatic latent image formed by uniformly exposing and scanning the uniformly charged photoreceptor surface is visualized,An electrostatic latent image formed on the surface of the photosensitive member by the developing device using a developing device that attaches toner to the surface of the photosensitive member and a transfer device that transfers the toner attached to the surface of the photosensitive member to a recording medium. 15. The electrostatic latent image is visualized by transferring the toner adhered to the recording medium to the recording medium by the transfer device.Or15. The method for measuring a photoreceptor sensitivity distribution according to 15.
  The invention according to claim 17 is the data acquisition step.In the step (D) of acquiring the image data, when the electrostatic latent image formed by uniformly exposing and scanning the uniformly charged photoreceptor surface is visualized,Claims: The present invention uses a visualization device that attaches toner to the surface of the photoreceptor, and visualizes the electrostatic latent image by attaching toner to the electrostatic latent image on the surface of the photoreceptor using the visualization device. Term 10, 11, 12, 13, 14Or15. The method for measuring a photoreceptor sensitivity distribution according to 15.
  The invention according to claim 18 refers to a storage area for storing the sensitivity of the photosensitive member and the film thickness of the photosensitive layer in association with each other, and based on the sensitivity of the photosensitive member, the entire visualization region of the photosensitive member. A film thickness distribution acquisition step of acquiring a film thickness distribution state of the photosensitive layer in claim 10, 11, 12, 13, 14, 15, 16.Or17. The method for measuring sensitivity of a photoreceptor according to item 17.
[0065]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. The present embodiment shows an application example to a photosensitive member sensitivity distribution measuring apparatus that measures the sensitivity distribution of a photosensitive member applied to an electrophotographic image forming apparatus.
[0066]
FIG. 1 is a block diagram showing a configuration example of the photosensitive member sensitivity distribution measuring apparatus according to the present embodiment. As shown in FIG. 1, the photosensitive member sensitivity distribution measuring apparatus 1 according to the present embodiment includes an input device 2 serving as a data acquisition unit that acquires image data of an image formed using a photosensitive member whose sensitivity is to be measured. The image processing apparatus 3 that performs various processes on the image data input by the input apparatus 2 and the image display unit 10 that displays the sensitivity distribution state of the photoconductor acquired by the processing in the image processing apparatus 3 are provided.
[0067]
The input device 2 photoelectrically converts optical information of an optically read image, and a reading unit (not shown) that optically reads an image formed on a sheet using a photoconductor to be measured for surface sensitivity. A photoelectric conversion unit (not shown) that acquires image data including optical information of each pixel constituting the image. Examples of the optical information include information representing brightness, reflectance, density, brightness, chromaticity, and the like. Description of the reading unit and the photoelectric conversion unit is omitted because it is a known technique, but the input device 2 is realized by, for example, a scanner, a digital camera (electronic still camera, video camera), a microdensitometer, or the like. Is possible. The input device 2 according to the present embodiment optically reads an image formed on a recording medium such as paper using a photoconductor that is a target of surface sensitivity measurement.
[0068]
Note that the input device 2 of the present embodiment optically reads an image formed on a recording medium using a photoconductor that is a target of surface sensitivity measurement. However, the present invention is not limited to this. The toner image formed on the photoconductor before being transferred onto the paper may be optically read.
[0069]
Further, the input device 2 according to the present embodiment acquires image data by photoelectrically converting an optically read image. However, the present invention is not limited to this, and a photoconductor to be measured for surface sensitivity. By using a medium reading device that stores image data acquired in advance by reading an image formed on a sheet using a storage medium, and acquires the image data by reading the image data stored in the storage medium The input device 2 may be realized.
[0070]
Here, a photoconductor to be measured for surface sensitivity in the present embodiment and an image forming apparatus that forms an image on a sheet using the photoconductor will be described with reference to FIG.
[0071]
FIG. 2 is a longitudinal side view schematically showing an image forming apparatus for forming an image on a sheet using a photoconductor that is a target of surface sensitivity measurement in the present embodiment. A main body housing 41 having a housing shape of the printer 40 is provided with a manual feed tray 42 on which recording media to be manually fed are stacked, and a paper discharge tray 43 on which recording media after image formation is discharged.
[0072]
In the main body housing 41, a paper feed tray 44 that holds a plurality of recording media stacked is provided. In the main body housing 41, a recording medium conveyance path 47 is provided that communicates from the paper feed tray 44 or the manual feed tray 42 to the paper discharge tray 43 via the printer engine 45 and the fixing unit 46.
[0073]
The printer engine 45 includes a photosensitive member 48 provided at the center of the printer engine 45, a charging roller 49 as a charging device disposed around the photosensitive member 48, an exposure scanning device 50, a developing unit 51, and a pre-transfer charger 52. The image forming apparatus includes a transfer charger 53, a separation charger 54, a separation claw 55, a pre-cleaning charger 56, a cleaning unit 57, a charge removal lamp 58, and the like as a transfer device.
[0074]
Since the input device 2 of the photosensitive member sensitivity distribution measuring apparatus 1 acquires image data by optically reading an image formed on a recording medium, in this embodiment, the developing unit 51, the transfer charger 53, and the fixing unit. A visualization apparatus is realized by 46 and the like.
[0075]
In the case of using an input device that acquires image data by optically reading a toner image that has been formed on the photoreceptor and has not yet been transferred to paper, the developing unit 51 that forms the toner image on the surface of the photoreceptor 48 is used. An imaging device is realized.
[0076]
The exposure scanning device 50 includes a light source (not shown) that emits light, a polygon mirror 59 that scans the light emitted from the light source, a motor 60 that rotates the polygon mirror 59, although the description is omitted because it is a known technique. In addition, a mirror 62 that reflects the light scanned by the polygon mirror 59 toward the photoconductor 48 through the lens 61 is provided.
[0077]
Next, the photoconductor 48 will be described. Although not shown in detail because it is a known technique, the photoconductor 48 includes a cylindrical or columnar conductive support 48a and a photosensitive layer 48b provided on the outer peripheral surface of the conductive support 9a. ing.
[0078]
First, the conductive support 48a will be described. The conductive support 48a has a volume resistance of 10^-10A material having conductivity of Ω · cm or less is used. Examples of the conductive material include metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, and metal oxides such as tin oxide and indium oxide. As a conductive support, these conductive materials are coated with film-like plastic, cylindrical plastic, paper, etc. by vapor deposition or sputtering, or aluminum, aluminum alloy, nickel, stainless steel, etc. After the plate is made into a raw pipe by a method such as extrusion or drawing, a pipe whose surface is treated by cutting, superfinishing, polishing, or the like is used.
[0079]
Moreover, the endless nickel belt and the endless stainless steel belt disclosed in Japanese Patent Laid-Open No. 52-36016 can be used as the conductive support 48a.
[0080]
Furthermore, the conductive support 48a may be formed by coating a conductive powder dispersed in an appropriate binder resin on a cylindrical or columnar support and providing a conductive layer. In this case, as the conductive powder, metal powder such as carbon black, acetylene black, aluminum, nickel, iron, nichrome, copper, zinc, silver, or metal oxide powder such as conductive tin oxide, ITO, etc. Is mentioned. Examples of the binder resin for dispersing the conductive powder include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-acetic acid. Vinyl copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin , Epoxy resins, melamine resins, urethane resins, phenol resins, alkyd resins, and other thermoplastic resins, thermosetting resins, and photocurable resins.
[0081]
The conductive layer can be provided by dispersing and applying the above-described conductive powder and binder resin in a suitable solvent as necessary. Examples of the solvent used for generating the conductive layer include tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, and the like. Furthermore, a heat-shrinkable tube containing the above-mentioned conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or polytetrafluoroethylene is placed on a suitable cylindrical substrate. By providing, a conductive support provided with a conductive layer can also be used favorably.
[0082]
Next, the photosensitive layer 48b will be described. The photosensitive layer 48b has a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, and a charge generation layer provided on the charge transport layer. There is a reverse layer type.
[0083]
A charge generation material is contained in the single layer type photosensitive layer and the charge generation layer used for the forward layer type and the reverse layer type. Various materials can be used as the charge generation material. Representative examples include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squalic acid dyes, various phthalocyanine pigments, naphthalocyanine pigments, and azurenium salts. And dyes.
[0084]
The charge generation layer is formed by dispersing the above-described charge generation material together with a binder resin in an appropriate solvent, if necessary, applying this onto a conductive support, and drying. The film thickness of the charge generation layer is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm. In dispersing the charge generating material and the binder resin in the solvent, various dispersing methods such as a ball mill, an attritor, a sand mill, and an ultrasonic wave can be used. Various dispersion methods such as a ball mill, an attritor, a sand mill, and an ultrasonic wave are well-known techniques, and thus description thereof is omitted.
[0085]
The binder resin used in the charge generation layer as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, and poly-N-vinyl. Examples include carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. . Among these, polyvinyl acetal typified by polyvinyl butyral is used favorably. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.
[0086]
Solvents used in the formation of the charge generation layer include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. Can be mentioned. In particular, a ketone solvent, an ester solvent, and an ether solvent can be favorably used as the solvent used in forming the charge generation layer.
[0087]
Next, the charge transport layer will be described. The charge transport layer can be formed by applying a coating solution formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent on the above-described charge generation layer and drying. The film thickness of the charge transport layer is preferably about 5 to 100 μm, and in particular, high resolution image formation is possible by setting the thickness to 5 to 15 μm. Various additives such as a plasticizer, a leveling agent, and an antioxidant can be added to the charge transport layer as necessary.
[0088]
Charge transport materials include hole transport materials and electron transport materials. Among these, examples of the charge transport material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3, Examples thereof include electron-accepting substances such as 7-trinitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
[0089]
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials. These charge transport materials may be used alone or in combination of two or more.
[0090]
Examples of the binder resin used for forming the charge transport layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate. Copolymer, polyvinyl acetate, polyvinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin And thermoplastic or thermosetting resins such as melamine resin, urethane resin, phenol resin, and alkyd resin.
[0091]
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin.
[0092]
Examples of the solvent used for forming the charge transport layer include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.
[0093]
In the photoreceptor 48 of the present invention, a plasticizer or a leveling agent may be added to the charge transport layer. As a plasticizer added to the charge transport layer, a plasticizer used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as it is. The amount of the plasticizer used is suitably about 0 to 30% by weight with respect to the binder resin. As a leveling agent added to the charge transport layer, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, or oligomers can be used. The amount of the leveling agent used is suitably 0 to 1% by weight based on the binder resin.
[0094]
By the way, since the surface state of each layer of the photoconductor 48 and the film thickness of each layer are non-uniform, it causes the sensitivity unevenness of the photoconductor 48, and therefore the surface state of each layer of the photoconductor 48 and the film thickness of each layer. In order to make the thickness uniform, an undercoat layer may be provided between the photosensitive layer 48b and the conductive support 48a, or a protective layer may be laminated on the photosensitive layer 48b.
[0095]
The undercoat layer provided between the conductive support 48a and the photosensitive layer 48b is suitably and preferably set to a film thickness of 0 to 5 μm. The undercoat layer generally comprises a resin as a main component. However, considering that the photosensitive layer 48b is applied thereon with a solvent, these resins are resins having high solvent resistance with respect to general organic solvents. It is desirable to be. As described above, resins having high solvent resistance to general organic solvents include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, and polyurethane. Curable resins that form a three-dimensional network structure, such as melamine resin, phenol resin, alkyd-melamine resin, and epoxy resin.
[0096]
Further, a fine powder pigment of a metal oxide that can be exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, etc. may be added to the undercoat layer in order to prevent moire and reduce residual potential. .
[0097]
Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, the undercoat layer of the present invention includes Al.₂O₃Anodic oxidation, organic materials such as polyparaxylylene (parylene), SiO₂, SnO₂TiO₂, ITO, CeO₂A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used.
[0098]
Similar to the formation of the photosensitive layer 48b, the undercoat layer can be formed by applying various materials for forming the undercoat layer dispersed in an appropriate solvent using the various coating methods described above.
[0099]
Materials used for the protective layer laminated on the photosensitive layer 48b include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide. , Polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene Resins such as polymers, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resins can be used.
[0100]
The protective layer preferably contains wear-resistant particles for the purpose of improving wear resistance. Abrasion-resistant particles include fluorine resins such as polytetrafluoroethylene, silicone resins or metal oxides such as titanium oxide, tin oxide, aluminum oxide, silicon oxide, zirconium oxide, and inorganic materials such as potassium titanate. Etc. can be added. In particular, from the viewpoint of wear resistance, metal oxides are preferable as the wear-resistant particles. The particle diameter of the wear-resistant particles is preferably 0.2 to 0.8 μm, and more preferably 0.3 to 0.7 μm. In particular, since the generation of scratches having a size of 5 to 50 μm related to abnormal images due to white streaks and filming is extremely reduced, it is possible to use a metal oxide having a particle size of 0.3 to 0.6 μm. Very preferable. Among metal oxides, aluminum oxide is preferable because it does not cause a reduction in image quality due to reaction and accumulation with various impurities generated during image formation. Further, among aluminum oxides, those produced by a vacuum process are very preferable because the particle diameter is almost constant and the purity is high.
[0101]
Further, in order to give the protective layer charge mobility, the protective layer usually contains a charge transport material contained in the charge transport layer. Thereby, the residual potential can be lowered, which is preferable. The thickness of the protective layer is suitably about 0.11 to 10 μm.
[0102]
In addition, in the photoreceptor 48 of the present invention, an intermediate layer can be provided between the photosensitive layer 48b and the protective layer. In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, various coating methods as described above can be employed. The thickness of the intermediate layer is suitably about 0.05 to 2 μm.
[0103]
As a method of laminating each layer forming the photosensitive layer 48b, a dip coating method, a ring coating method, a spray coating method, a roll coating method, a blade coating method, a beat coating method (beat coating), a nozzle coating method (nozzle coating), Any coating method such as a spinner coating method (spinner coating) can be used, but at least one of the plurality of layers forming the photosensitive layer 48b is formed by using the spray coating method in the photoreceptor 48 of the present embodiment. The photosensitive layer 48b is formed. Further, the photoreceptor of the present embodiment has a photosensitive layer 48b in which the outermost layer is formed by using a spray coating method. Various coating methods such as dip coating, ring coating, spray coating, roll coating, blade coating, beat coating (beat coating), nozzle coating (nozzle coating), and spinner coating (spinner coating). Since the construction method is a known technique, a description thereof will be omitted.
[0104]
By the way, conventionally, the dip coating method has been mainly used as the coating method of the photosensitive layer 48b. However, although the dip coating method is excellent in mass productivity and can obtain a photoreceptor with a smooth surface shape, it requires a large amount of coating solution, so the coating solution requires long-term stability of several months or more. It is done. In addition, in the dip coating method, it is inevitable that the coating film slips due to gravity, so it is easy to have a long-range film thickness gradient in the vertical direction. Easy to hold. As described above, when each layer forming the photosensitive layer 48b is formed by the dip coating method in the photosensitive member 48 having the photosensitive layer manufactured by laminating a plurality of layers, the time for the lower layer to contact the upper layer coating solution is set. Since it is long, the upper layer cannot be applied when the lower layer is a material that dissolves in the upper layer coating solution.
[0105]
On the other hand, the spray coating method for forming at least one layer of the photosensitive layer 48b of the present embodiment is slightly inferior in mass productivity, but can form a coating film even when the stability of the coating solution is poor. Further, the spray coating method can form a coating film even when the upper layer coating solution dissolves the lower layer because the time during which the upper layer coating solution contacts the lower layer is short. In the spray coating method, if the spray gun is scanned while rotating the substrate, the coating film is formed in the same manner at any location on the substrate.
[0106]
However, on the other hand, in the spray coating method, the coating liquid sprayed from the spray gun during spray coating is subjected to evaporation of the solvent, mixing of impurities, and alteration of the coating liquid before reaching the substrate. Easily, the surface properties and characteristics of the coating film may vary depending on the coating environment (temperature, humidity, and other reactive gas concentrations). In addition, it is inevitable that the coating liquid that has reached the substrate is compressed by the natural evaporation of the solvent, and thus a process of applying a new coating liquid is inevitable. , Coating volume, coating pressure, coating booth size, etc.). For this reason, when film formation by spray coating is performed, there is a problem that spotted film thickness unevenness having a size of several hundred μm to several tens of mm is likely to occur. In particular, when the outermost layer is formed using a spray coating method, the film thickness unevenness of the outermost layer and the unevenness of the surface state appear as the sensitivity unevenness of the photoreceptor 48 as they are.
[0107]
As described above, the nonuniformity of the sensitivity of the photoconductor 48 caused by the non-uniform film thickness and surface condition of the coating film is slightly generated in an image formed using the photoconductor 48, but the density unevenness is generated. . The density unevenness that occurs varies greatly depending on the manufacturing method of the photoconductor 48. In contrast, the dip coating method tends to cause a gentle gradation in the screen, whereas the spray coating method in which the coating solution is applied in the form of a mist. , Coating unevenness of about 1 to 20 mm is likely to occur.
[0108]
As described above, in order to obtain only the sensitivity unevenness of the photoconductor 48, it is preferable to determine the sensitivity nonuniformity of the photoconductor based on the visualized image from which noise not caused by the photoconductor 48 is removed.
[0109]
Various methods for removing noise can be considered as follows. For example, spike noise can be removed by applying a median filter in the main scanning direction and the sub-scanning direction. Further, noise that is not caused by the photoconductor may be removed by performing fast Fourier transform (FFT) and removing band components other than the density unevenness frequency of the photoconductor. However, noise in the main scanning and sub-scanning directions generated in electrophotography is not necessarily spike-like noise or high-frequency noise but also low-frequency noise. With respect to an image in which such noise has occurred, it has been difficult to remove low-frequency noise by a noise removal method using a median filter or FFT.
[0110]
On the other hand, in the present embodiment, noise can be removed by performing the following processing by the image processing apparatus 3.
[0111]
Next, the image processing apparatus 3 will be described. The image processing device 3 includes an image storage unit 4 that temporarily stores image data photoelectrically converted by the photoelectric conversion unit of the input device 2. Although not particularly illustrated, the image storage unit 4 includes a storage medium such as a RAM and a hard disk, and a writing device that stores optical information in the storage medium. The image data stored in the image storage unit 4 is read by the average value calculation unit 5 and used for the calculation of the following equation (1). Further, the image data stored in the image storage unit 4 is subjected to an X-direction noise removal process and a Y-direction noise removal process executed by the X-direction noise removal unit 7 and the Y-direction noise removal unit 6.
[0112]
The average value calculation unit 5 calculates an overall average value obtained by averaging the optical information of each pixel over the entire image by performing the calculation of the expression (1) based on the image data stored in the image storage unit 4. To do.
[0113]
[Expression 1]

[0114]
Based on the image data stored in the image storage unit 4, the Y-direction noise removal unit 6 and the X-direction noise removal unit 7 generate noise data in which the pixels having optical information exceeding the threshold value are linearly continuous from the image data. The noise removal process to remove is performed. Hereinafter, in the noise data, noise having directionality in the X direction (main scanning direction) is referred to as X direction noise, and noise having directionality in the Y direction (sub scanning direction) is referred to as Y direction noise. The structure of the Y direction noise removing unit 6 and the X direction noise removing unit 7 and each noise removing process executed by the Y direction noise removing unit 6 and the X direction noise removing unit 7 will be described later. In this embodiment, calculation parameters stored in the parameter storage unit 8 connected to the Y direction noise removing unit 6 and the X direction noise removing unit 7 are used. The calculation parameters stored in the parameter storage unit 8 include a threshold value of optical information of each pixel, the number i of pixels related to calculation of an average value in various noise removal processes described later, and the like.
[0115]
The image data from which the X direction noise and the Y direction noise have been removed by the Y direction noise removing unit 6 and the X direction noise removing unit 7 is stored in the processed image storage unit 9.
[0116]
The post-processing image storage unit 9 includes a storage medium that actually stores the image data from which the X direction noise and the Y direction noise have been removed, and a writing device (none of which is shown) that stores the image data in the storage medium. It has. In the post-processing image storage unit 9, for example, a hard disk, a flexible disk, a CD-R, or the like can be used as a storage medium.
[0117]
The image display unit 10 displays an image reflecting the sensitivity of the photoconductor after noise removal based on the optical information of the image data stored in the processed image storage unit 9. The image display unit 10 can be realized by a CRT, a liquid crystal monitor, or the like, for example. In the present embodiment, as an image reflecting the sensitivity of the photoconductor, an image showing the charge amount or electric field strength of the surface of the photoconductor after charging and exposure based on the optical information of the image data after noise removal is shown by shading. The image is displayed on the image display unit 10.
[0118]
In the present embodiment, the image based on the image data after noise stored in the processed image storage unit 9 is displayed on the image display unit 10, but the present invention is not limited to this. These images may be directly displayed on the image display unit 10 without passing through the processed image storage unit 9.
[0119]
Next, the configurations of the Y direction noise removing unit 6 and the X direction noise removing unit 7 and the noise removing process executed by the Y direction noise removing unit 6 and the X direction noise removing unit 7 will be described with reference to FIGS. explain.
[0120]
As described above, when an image is formed using the electrophotographic method, for example, linear noise such as noise having directionality in the X direction (X direction noise) and noise having directionality in the Y direction (Y direction noise). May occur in the electrostatic latent image. Due to the occurrence of this linear noise, in the image obtained by visualizing the electrostatic latent image, the optical information exceeding the threshold is not caused by the sensitivity unevenness of the photosensitive member, and the vertical and horizontal stripes in which the optical information exceeds the threshold value are continuously linear. Such image structures Ny and Nx (see FIGS. 3 and 7) are superimposed. In the present embodiment, an image structure Ny generated due to Y direction noise is a vertical stripe, and an image structure Nx generated due to X direction noise is a horizontal stripe. In the present embodiment, the image data of the vertical stripe Ny and horizontal stripe Nx portions in the image data acquired by the input device 2 is noise data.
[0121]
The Y-direction noise removal unit 6 and the X-direction noise removal unit 7 perform a noise removal process described below, thereby removing vertical stripes Ny and horizontal stripes Nx generated in the image.
[0122]
Note that the noise removal processing according to the present embodiment is effective when the direction of occurrence of noise having directionality is known. For this reason, prior to the noise removal process, a noise direction analysis process for analyzing the noise generation direction is performed. By this noise direction analysis processing, functions as a noise direction determination means and a noise direction determination step are realized.
[0123]
In general, the noise direction is almost the direction corresponding to the main scanning direction or the sub-scanning direction of optical writing as described above. The direction may be fixed in the main scanning direction or the sub-scanning direction of optical writing.
[0124]
Moreover, in this Embodiment, the function as a direction number determination means and a direction number determination step is implement | achieved by noise direction analysis processing.
[0125]
The analysis of the noise direction can be easily realized by using a known image analysis technique. Therefore, the description is omitted here, the noise direction analysis process is completed, and the noise generation direction is known. It will be explained as being. For example, it is possible to extract only noise from image information and determine the direction of noise based on the extracted information.
[0126]
First, as shown in FIG. 3, in the image 11 having a slight change in shading formed by uniformly charging, exposing and developing the photoconductor 48 and transferring and fixing the photoconductor 48, it is caused by noise in the Y direction. A noise removal process for removing the vertical stripe Ny from the image 11 by the Y-direction noise removal unit 6 when the vertical stripe Ny is superimposed will be described with reference to FIGS.
[0127]
Here, FIG. 4 is a block diagram showing the configuration of the Y direction noise removing unit 6, and FIG. 5 is a flowchart for schematically explaining the noise removing process executed by the Y direction noise removing unit 6. In the noise removal process executed by the Y-direction noise removal unit 6, first, the image data stored in the image storage unit 4 is copied to the pre-correction image data storage unit 12 (step S1).
[0128]
The image average value calculation unit 13 acquires the average value Pave of the optical information of all pixels based on the image data copied to the pre-correction image data storage unit 12 (S2). The image average value calculation unit 13 of the present embodiment reads the average value Pave of the optical information of all the pixels calculated by the average value calculation unit 5, and acquires this value as the average value Pave of the optical information of all the pixels. The average value Pave may be stored in the parameter storage unit 8 in advance, and the average value Pave stored in the parameter storage unit 8 may be read out during the noise removal process.
[0129]
Next, from the image data stored in the pre-correction image data storage unit 12, the target pixel determination unit 14 performs P (x, y) (where x = 1 to N, y = 1 to M, ( N and M are determined as a pixel of interest P (x, y) (S3). In the present embodiment, in step S4, x and y of the pixel of interest P (x, y) are set to x = 1 and y = 1, respectively. Note that the pixel of interest P (x, y) has a visible area of 100 mm on the surface of the photoreceptor.²It is determined so that one point is set for each unit divided by the following units. At this time, the visualized area on the surface of the photoreceptor is 50 mm.²It is preferable to divide into the following, 0.01 to 25 mm²It is more preferable to divide into two.
[0130]
Then, by calculating the following expression (2) by the peripheral pixel average value calculation unit 15, the optical information average value Pave (2n + 1 pixels) including the target pixel P (x, y) in the Y direction is included. x, y) is calculated (S5). Here, functions as an average value acquisition means and an average value acquisition step are executed. At this time, “n” of the number of pixels 2n + 1 for calculating the average value Pave (x, y) is obtained from the number of pixels i related to the calculation of the average value stored in the parameter storage unit 8.
[0131]
[Expression 2]

[0132]
Subsequently, the target pixel correction unit 16 uses the average value Pave (x, y) calculated in step S5 and the average value Pave of the optical information of the pixels of the entire image calculated by the average value calculation unit 5 to use the target pixel Pave. The optical information of (x, y) is subjected to the calculation of the following equation (3) to obtain P ′ (x, y) (S6). Here, functions as a noise removing means and a noise removing step are executed.
[0133]
[Equation 3]

[0134]
Thereby, from the optical information of the target pixel P (x, y), the average value Pave (x, y) of the optical information in the range of ± n pixels in the Y direction around the target pixel P (x, y) is used as a threshold value. It is possible to obtain a pixel P ′ (x, y) having optical information that has been subtracted and from which vertical stripes Ny generated by noise that is not caused by non-uniform sensitivity of the photosensitive member are removed.
[0135]
In the photosensitive member sensitivity measuring apparatus 1 of the present embodiment, a plurality of (2n + 1 pixels in this embodiment) pixels including any target pixel P (x, y) in the image data along the continuous direction of the vertical stripe Ny. By setting an average value obtained by averaging the optical information in the threshold value as a threshold value, a threshold value suitable for image data from which vertical stripes Ny are to be removed is set as compared with a case where a preset default value is set as the threshold value. Can do.
[0136]
In the present embodiment, the average value Pave (x, y) of the optical information of the pixels in the range of ± n pixels in the Y direction around the target pixel P (x, y) is calculated. The optical information average value of k pixels (k is an integer) in the Y direction passing through the target pixel P (x, y) may be calculated. At this time, the target pixel P (x, y) does not need to be at the center in the range in which the average is calculated in the Y direction.
[0137]
However, in order to ensure the removal accuracy of the Y-direction noise Ny, it is preferable that the target pixel P (x, y) is at the center in the range in which the average is calculated.
[0138]
In this embodiment, in order to make the average density of the processed image substantially equal to that of the image before processing, the average value Pave of the optical information of the pixels of the entire image is added as shown in the equation (3). However, the present invention is not limited to this. When only the density fluctuation of the image data after noise removal is necessary, it is not always necessary to add Pave, and an arbitrary value is added instead of Pave. May be. Even in such a case, the process can be efficiently performed by storing an arbitrary value instead of Pave in the parameter storage unit 8.
[0139]
Further, in the present embodiment, the size of the number k of pixels including the target pixel P (x, y) to be averaged and extending in the Y direction is not limited. Even if it is too much, sufficient noise removal cannot be performed, so the number of pixels k needs to be set in a range in which high correlation is obtained with respect to the target pixel P (x, y).
[0140]
Then, the obtained optical information of P ′ (x, y) is stored in the corrected image data storage unit 17 in association with the coordinates of this pixel (S7), and the x in the target pixel P (x, y) is stored. 1 is added (S8), and the process from step S5 to S8 is repeated until it is determined by the process end determination unit 18 that x indicated by x + 1 is greater than N (N in S9).
[0141]
When the process end determination unit 18 determines that x indicated by x + 1 is greater than N (Y in S9), 1 is added to y (S10), and the process end determination unit 18 indicates y + 1. Until it is determined that y is greater than M (Y in S11), the processes from Steps S5 to S10 are repeated (N in S11).
[0142]
Since the present invention does not prescribe the processing at both ends, if y <0 or y> M in the calculation of Pave (x, y), Pave (x, y) = 0 may be set. Pave (x, y) = Pave (x, 0) or Pave (x, M) may be used. The parameter M in this case is also stored in the parameter storage unit 8.
[0143]
Thereby, an arbitrary target pixel P (x, y) in the target image to be processed is set for all the pixels of the target image, and the vertical stripe Ny is removed from the optical information of all the pixels in the target image. It is possible to suppress the occurrence of a gap between the image data of the vertical stripe portion and the other image data by performing the noise removal process.
[0144]
At this time, in the photoconductor sensitivity measuring apparatus 1 according to the present embodiment, the target pixel P (x, y) is set to 100 mm over the entire image forming area of the photoconductor.²Since it is determined so that one point is set for each unit divided into the following units, it is possible to measure the sensitivity distribution of the photoconductor intended for mounting in a high-resolution image forming apparatus with high density.
[0145]
When the noise direction in the image data is one direction, the image data from which the vertical stripe Ny is removed is stored in the post-processing image storage unit 9. The post-processing image storage unit 9 stores the optical information after removing the vertical stripe Ny from the optical information of each pixel constituting the image data in association with the coordinate information specifying each pixel position.
[0146]
Next, as shown in FIG. 7, an image formed by uniformly charging, exposing and developing the photoconductor 48 using a photoconductor 48 whose sensitivity distribution is to be measured, and transferring and fixing the image on a sheet. In addition to the image S caused by the sensitivity unevenness of the photoconductor 48, when the vertical stripe Ny caused by the Y direction noise and the horizontal stripe Nx caused by the X direction noise are superimposed, the vertical stripe Ny and A noise removal process for removing the horizontal stripe Nx will be described with reference to FIGS.
[0147]
A vertical streak caused by noise in the Y direction is formed on an image formed by uniformly charging, exposing and developing the photoconductor 48 using a photoconductor 48 whose sensitivity distribution is to be measured, and transferring and fixing the image on a sheet. When the horizontal streak Nx resulting from Ny and X direction noise is superimposed, the vertical streak Ny is removed as described above, and the image data after the removal of the vertical streak Ny is performed in the X direction. The noise removal unit 7 performs an X-direction noise removal process described below. Although the description of the removal of the vertical stripe Ny is omitted, in this case, the function as the first average value acquisition means and the first average value acquisition step is executed in step S5 of FIG. 5, and the subtraction is performed in step S6. Functions as means and subtraction steps are executed.
[0148]
Here, FIG. 8 is a block diagram showing the configuration of the X-direction noise removing unit 7, and FIG. 9 is a flowchart schematically explaining the noise removing process executed by the X-direction noise removing unit 7. In the noise removal processing executed by the X direction noise removing unit 7, first, the image data stored in the corrected image data storage unit 17 of the Y direction noise removing unit 6 is stored in the uncorrected image data storage unit 19 ( Step S20).
[0149]
The image average value calculation unit 20 acquires the average value Pave of the optical information of all pixels based on the image data after the removal of the vertical stripe Ny stored in the pre-correction image data storage unit 19 (S21). Similar to the image average value calculation unit 13, the image average value calculation unit 20 of the present embodiment reads the average value Pave of the optical information of all the pixels calculated by the average value calculation unit 5, and reads this value for all the pixels. Obtained as the average value Pave of the optical information.
[0150]
Next, P ′ (x, y) (where x = 1 to N, y =) is obtained from the image data after the removal of the vertical stripe Ny stored in the pre-correction image data storage unit 19 by the target pixel determination unit 21. 1 to M, (N and M are positive integers)) are determined as the target pixel P ′ (x, y) (S22). In the present embodiment, in step S23, x and y of the pixel of interest P ′ (x, y) are set to x = 1 and y = 1, respectively.
[0151]
Then, the average value P of the optical information of 2n + 1 pixels including the pixel of interest P ′ (x, y) is included in the X direction by performing the calculation of the following expression (4) by the peripheral pixel average value calculation unit 22. 'ave (x, y) is calculated (S24). Here, functions as a second average value acquisition means and a second average value acquisition step are executed. At this time, “n” of 2n + 1 pixels for calculating the average value P′ave (x, y) is also related to the calculation of the average value stored in the parameter storage unit 8 as in the process of FIG. Obtained from the number of pixels i.
[0152]
[Expression 4]

[0153]
Subsequently, the target pixel correction unit 23 uses the average value P′ave (x, y) calculated in step S24 and the average value Pave of the optical information of the pixels of the entire image calculated by the average value calculation unit 5, and P ″ (x, y) is obtained by performing the following equation (5) on the optical information of the pixel P ′ (x, y) (S25). When there are a plurality of noise generation directions in the image data, functions as a noise removal means and a noise removal step are executed here.
[0154]
[Equation 5]

[0155]
Thereby, from the optical information of the target pixel P ′ (x, y), the average value P′ave (x, y) of the optical information in the range of ± n pixels in the Y direction with the target pixel P ′ (x, y) as the center. ) Is subtracted, and P ″ (x, y) obtained by removing the X-direction noise Nx not caused by the non-uniform sensitivity of the photoconductor in addition to the Y-direction noise Ny not caused by the non-uniform sensitivity of the photoconductor can be obtained.
[0156]
Then, the obtained optical information of P ″ (x, y) is stored in the corrected image data storage unit 24 in association with the coordinates of this pixel (S26), and at the target pixel P ′ (x, y). 1 is added to x (S27), and the processing from step S24 to S27 is repeated until the processing end determination unit 25 determines that x indicated by x + 1 is greater than N (N in S28).
[0157]
When the process end determination unit 25 determines that x indicated by x + 1 is greater than N (Y in S28), 1 is added to y (S29), and the process end determination unit 25 indicates y + 1. Until it is determined that y is greater than M (Y in S30), the processing from step S24 to S29 is repeated (N in S30).
[0158]
Since the present invention does not prescribe the processing at both ends, when x <0 or y> N in the calculation of Pave (x, y), Pave (x, y) = 0 may be set. Pave (x, y) = Pave (0, y) or Pave (N, y) may be set. The parameter N in this case is also stored in the parameter storage unit 8.
[0159]
Thereby, even when the noise generation direction is a plurality of directions of the Y direction and the X direction, the noises Nx and Ny having directivity regardless of the surface state of the photoreceptor are effectively removed in each continuous direction. be able to.
[0160]
Further, in the photosensitive member sensitivity measuring apparatus 1 of the present embodiment, a plurality (2n + 1 in the present embodiment) including an arbitrary pixel of interest P (x, y) in the image data along the continuous direction of the vertical stripe Ny. A plurality of (in the present embodiment, including an arbitrary pixel of interest P ′ (x, y) in the image data along the continuous direction of the horizontal stripe Nx. By setting an average value obtained by averaging the optical information of (2n + 1) pixels as a threshold value, a threshold value suitable for image data from which vertical stripes Ny and horizontal stripes Nx are removed is set, and optical information of all pixels is set. By subtracting this threshold value from, it is possible to suppress the occurrence of a difference between the image data of the vertical stripe Ny and horizontal stripe Nx portions and the other image data by performing the noise removal process.
[0161]
The image data from which the vertical stripe Ny and the horizontal stripe Nx are removed is stored in the post-processing image storage unit 9. The post-processing image storage unit 9 stores the optical information after removing the vertical stripe Ny and the horizontal stripe Nx of each pixel constituting the image data in association with the coordinate information specifying each pixel position.
[0162]
Next, the image display unit 10 will be described. As described above, the image display unit 10 determines the size of the optical information based on the optical information of the image data stored in the processed image storage unit 9 and from which the vertical streak Ny or the vertical streak Ny and the horizontal streak Nx are removed. An image converted into the magnitude of the charged charge amount or the strength of the electric field strength is displayed as the sensitivity of the photoconductor 48. Here, functions as a sensitivity acquisition means and a sensitivity acquisition step are realized.
[0163]
According to the present embodiment, only a noise image having a linear directivity can be easily obtained from an image obtained by developing a constant amount of writing light uniformly over the entire image forming area of the photosensitive member. Can be removed. As a result, an image S having a slight shading caused by uneven sensitivity of the photoconductor 48, that is, an image reflecting only the sensitivity distribution of the photoconductor 48, without repeating measurement or damaging the photoconductor. It can be displayed on the display unit 10. The image S caused by the sensitivity unevenness of the photoconductor 48 tends to be hidden by the noise component, but by removing the vertical and horizontal streaks as in the present embodiment, the image due to the sensitivity nonuniformity of the photoconductor 48 is obtained. Since only S can be displayed on the image display unit 10, the operator determines the sensitivity distribution state of the photoconductor 48 based on slight shading of the image displayed on the image display unit 10, thereby affecting the noise. Thus, it is possible to determine whether the sensitivity unevenness of the photoconductor 48 is good or bad.
[0164]
Since there is no linear relationship between the charged charge amount or electric field intensity of the photosensitive member 48 displayed on the image display unit 10 and the exposure amount, the above-described noise removal processing is performed in a plurality of stages near halftone images. It performs with respect to the several image formed by exposing with each adjusted exposure amount.
[0165]
In the present embodiment, the noise removal process for removing the horizontal streak Nx caused by the X-direction noise and the vertical streak Ny caused by the Y-direction noise has been described. However, the present invention is not limited to this. If the noise has directionality in the shape, it is possible to remove the noise in the oblique direction in the same manner. When noise having directionality in the oblique direction is generated in the electrostatic latent image, rotation processing is performed on the image data obtained by visualizing the electrostatic latent image, and the generated abnormal image structure By adjusting the directivity to be the X direction or the Y direction, any noise having any directivity can be removed if the noise has a linear directivity. . Note that the rotation processing for image data can be easily realized by using a known image processing technique, and the description thereof is omitted here.
[0166]
Furthermore, in the present embodiment, the case where the input device 2 that optically reads an image formed on a sheet using the photoconductor 48 to be measured for surface sensitivity is described, but the image is formed on the photoconductor. When the image data is acquired by optically reading the toner image before being transferred to the paper, the transfer process and the fixing process are compared with the case of acquiring the image data from the image formed on the paper. Since it is possible to obtain image data that does not include noise generated during the transfer process and the fixing process, the sensitivity distribution of the photoconductor 48 can be measured with higher accuracy.
[0167]
In addition, in the present embodiment, the sensitivity distribution of the photoconductor 48 is reflected by an image showing the magnitude of the charged charge amount or the strength of the electric field in shades, but the present invention is not limited to this. The relationship between the sensitivity and the film thickness of the photosensitive layer 48b is acquired in advance by experiments or the like, and the relationship between the acquired sensitivity and the film thickness is stored in a storage device (not shown), so that the image data after the noise removal processing is performed. Instead of the sensitivity distribution of the photoreceptor 48 acquired based on the optical information, the distribution of the film thickness of the photosensitive layer 48b is reflected by an image showing the magnitude of the charged charge amount or the strength of the electric field in shades. Also good. At this time, a film thickness storage device is realized by a storage device that stores the relationship between the sensitivity and the film thickness, and based on this film thickness storage device, a process for displaying an image reflecting the distribution state of the film thickness of the photosensitive layer 48b is performed. Functions as a film thickness distribution acquisition means and a film thickness distribution acquisition step are realized.
[0168]
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, the same part as 1st embodiment is shown with the same code | symbol, and abbreviate | omits description.
[0169]
FIG. 10 is a block diagram showing the photoreceptor sensitivity measuring apparatus 30 of the present embodiment. The photoconductor sensitivity measuring apparatus 30 according to the present embodiment determines whether the sensitivity distribution state of the target photoconductor 48 is within a specified range based on the image data stored in the post-processing image storage unit 9. A sensitivity difference determination unit 31 is provided. In the determination by the sensitivity difference determination unit 31, a threshold value to be compared is required, and a parameter stored in the parameter storage unit 8 is used as this threshold value. The threshold value used for determination by the sensitivity difference determination unit 31 can be acquired by conducting an experiment or the like in advance.
[0170]
The sensitivity difference determination unit 31 is a difference between the optical information of the lowest optical information pixel acquired based on the image data stored in the processed image storage unit 9 and the optical information of the highest optical information pixel, A sensitivity deviation parameter such as an average value or standard deviation of optical information of all pixels is compared with a specified range acquired from the parameter storage unit 8, and if the sensitivity deviation parameter is within the specified range, the sensitivity deviation parameter is good. If it is out of the specified range, the image display unit 10 is displayed to indicate that it is defective. Examples of the storage medium for storing the sensitivity deviation parameter in the parameter storage unit 8 include a hard disk, a flexible disk, a CD-R, a CD-RW, a DVD, and an IC card. Here, functions as a distribution state determination means and a distribution state determination step are realized.
[0171]
In addition, although the sensitivity deviation parameter of this Embodiment showed about the example using the image data itself memorize | stored in the image memory | storage part 9, it is not restricted to this, For example, several adjacent pixels are made into one pixel. The average value of the optical information of those pixels may be used as the sensitivity deviation parameter.
[0172]
As in the conventional method, in order to determine whether or not the manufactured photoconductor 48 can be used, if a person determines the presence or absence of an abnormal image in the image formed image, There is a problem that individual differences and morning and evening time variations are likely to occur due to the determination by the method, but by measuring the sensitivity distribution by the photosensitive distribution measurement method of the present invention, by setting a specified range for determining the measured sensitivity distribution Therefore, it is possible to appropriately determine whether the photoconductor 48 is acceptable or not by eliminating the influence due to the variation of the skill of the evaluator and the difference between the devices of the image forming apparatus.
[0173]
In the distribution state determination step described above, if it is determined as defective, the sensitivity distribution is fed back to the method for manufacturing the photoconductor 48. For example, when the point where the sensitivity is significantly different from the whole is a dot, the exchange of the cutting tool, the feeding speed of the cutting tool, the rotation speed of the base 48a of the photosensitive member 48, the supply speed of the lubricating liquid, etc. Production conditions, coating conditions for the photosensitive layer 48b such as removal of foreign matter in the coating solution, or environment of the coating atmosphere such as temperature, humidity, dust concentration, strength and direction of airflow, etc. are determined in accordance with a predetermined priority order. Adjust to an appropriate state. Further, for example, when a portion where the sensitivity is significantly different from the whole is spotted, the coating conditions of the photosensitive layer 48b and the environment of the coating atmosphere are adjusted to an appropriate state according to a predetermined priority order. Thereby, the manufacturing method of the photoreceptor 48 can be improved appropriately.
[0174]
【Example】
Next, examples of the present invention will be described below. In the embodiment, a plurality of photoconductors 48 are actually produced as described below, and the produced photoconductors 48 are based on data obtained by performing the above-described noise removal processing on the produced photoconductors 48. The quality of the body 48 was compared.
[0175]
First, a mixture having the following composition was placed in a ball mill pot and ball milled for 72 hours using φ10 mm alumina balls.
Titanium oxide (CR-60: manufactured by Ishihara Sangyo): 50.0 parts by weight
Alkyd resin (Beckolite M6401-50: manufactured by Dainippon Ink and Chemicals): 15.0 parts by weight
Melamine resin (Super Becamine L-121-60: Dainippon Ink and Chemicals) 10.0 parts by weight
Methyl ethyl ketone (manufactured by Kanto Chemical): 31.7 parts by weight
[0176]
To this milling solution, 105.0 parts by weight of cyclohexanone (manufactured by Kanto Chemical Co., Inc.) was added, and ball milling was further performed for 2 hours to prepare an undercoat layer coating solution.
[0177]
A nickel seamless belt (Vickers hardness of 480 to 510, purity of 99.2% or more) having a circumference of 290.3 mm and a thickness of 30 μm is immersed in the coating solution for the undercoat layer, and used for the undercoat layer with respect to the nickel seamless belt. The coating solution was dip coated and dried at 135 ° C. for 25 minutes to form an undercoat layer having a film thickness of 6.5 μm.
[0178]
Subsequently, a mixture having the following composition was placed in a ball mill pot and ball milled for a time using a φ10 mm bowl.
A charge generating material having a chemical structure represented by (Chemical Formula 1) below (manufactured by Ricoh): 1.5 parts by weight
[Chemical 1]

A charge generating material having the chemical structure shown below (Chemical Formula 2) (Ricoh): 1.5 parts by weight
[Chemical 2]

Polyvinyl butyral resin (ESREC BLS: Sekisui Chemical Co., Ltd.): 1.0 part
Cyclohexanone (manufactured by Kanto Chemical): 80.0 parts by weight
[0179]
A charge generation layer coating solution prepared by adding 78.4 parts of cyclohexanone and 237.6 parts by weight of methyl ethyl ketone to the milling solution was prepared. In this charge generation layer coating solution, the nickel seamless belt laminated with the above undercoat layer was dipped, and the charge generation layer coating solution was dip coated on the nickel seamless belt laminated with the undercoat layer. And dried for 20 minutes to form a charge generation layer having a thickness of 0.12 μm.
[0180]
Next, a charge transport layer coating solution having the following composition was prepared.
Charge transport material having the chemical formula structure shown below (Chemical Formula 3) (Ricoh): 7 parts by weight
[Chemical Formula 3]

Polycarbonate resin (C-1400: manufactured by Teijin Chemicals): 10 parts by weight
Silicone oil (KF-50: manufactured by Shin-Etsu Chemical): 0.002 parts by weight
Tetrahydrofuran (manufactured by Kanto Chemical): 841.5 parts by weight
Cyclohexanone (manufactured by Kanto Chemical): 841.5 parts by weight
3-t-butyl-4-hydroxyanisole (manufactured by Tokyo Chemical Industry): 0.04 parts by weight
[0181]
The above-mentioned charge transport layer coating solution is spray-coated while rotating a nickel seamless belt on which an undercoat layer and a charge generation layer are laminated, and then dried at 140 ° C. for 30 minutes, so that the charge transport layer has a thickness of about 25 μm. To form a photoreceptor 48.
[0182]
Five photoconductors manufactured by changing the spray coating conditions of the photoconductor 48 manufactured by the above-described manufacturing method into five types are each cut to a width of 367 mm, and an arbitrary position 20 of the cut photoconductor 48 is obtained. The film thickness of the points was measured with a stylus type film thickness meter. Based on this measurement result, a value obtained by (maximum value of film thickness−minimum value of film thickness) was obtained as film thickness unevenness. They were 9 μm, 1.2 μm, 1.8 μm, 2.5 μm, and 3.0 μm.
[0183]
Subsequently, an acrylic adhesive having a thickness of about 40 μm was laminated on a urethane rubber having a thickness of 0.8 mm and a rubber hardness of 70, and a release paper was further laminated. This was punched with a Thomson blade to a length of 4 mm in width and 285 mm in length to make a detent guide.
[0184]
The above-mentioned detent guides were affixed to the inner surfaces of both side edges 5 mm from the end of the conductive support 48a (base) of the photoconductor 48 while peeling the release paper to prepare a photoconductor.
[0185]
The photoreceptor 48 thus produced was mounted on a modified IPSiO Color 5000 (manufactured by Ricoh) to produce an image forming apparatus. Create a gray image on the whole surface with a personal computer, charge voltage -800V, exposure 0.3μJ / cm²In black and white mode, an image was formed with 1200 dpi and 2 × 2 dots.
[0186]
Since the IPSiO Color 5000 remodeled machine used at this time was not a finished product, there were many horizontal and vertical stripes that were not caused by the photoreceptor 48.
[0187]
The formed image was captured as electronic information in a personal computer at a resolution of 100 dpi by a scanner having lightness linear input characteristics. Only the portion of the circumferential length 290.3 mm of the photosensitive member 48 was trimmed from the captured image information.
[0188]
In this image data, noises Nx and Ny in the X direction and Y direction are removed in the same manner as in the first embodiment described above, and the image after noise removal is smoothed with a filter size of 10 × 10 pixels, A denoised image was obtained. As a result, linear noise was generated in the image before the noise removal processing as shown in FIG. 2 or FIG. 6, whereas the image 11 ′ after the noise removal processing was a photoreceptor as shown in FIG. It can be seen that only the image S resulting from the 48 sensitivity unevenness, that is, only the sensitivity distribution is reflected. Here, an image formed using a photoconductor having a film thickness unevenness of 2.5 μm will be described.
[0189]
By the way, the exposure amount is 0.3 μJ / cm.²Then, the relationship shown by the following equation (6) exists between the image density (ID) and the electric field strength (E: V / μm) of the photosensitive member.
E = −20.1 × (1.19−ID) (6)
[0190]
Since the image data has optical information for each coordinate of the image (each coordinate on the surface of the photoreceptor), the exposure amount is 0.3 μJ / cm according to the equation (6).²Thus, the electric field strength of the photosensitive member at each coordinate can be obtained.
[0191]
Here, when the specified range for determining the allowable range of variation in electric field intensity in the image forming area is set to 0.35 V / μm, the film thickness unevenness of the photoconductor is 0.9 μm and 1.2 μm is acceptable. Thus, the other photoconductors 48 could be determined to be unacceptable.
[0192]
In the embodiment, the pixel in the visualized image is not completely aligned with the position of the pixel on the photoconductor 48. For example, the writing position of the photoconductor 48 is specified. By providing the means, it can be used for analysis of the cause of the sensitivity unevenness of the photoconductor 48.
[0193]
Subsequently, the photoconductor 48 was mass-produced under manufacturing conditions where the variation in electric field strength was within a specified range and the film thickness unevenness was 1.2 μm, and the above-described sensitivity distribution was measured every 50 manufactured. According to this, since the threshold of the sensitivity distribution was exceeded at the 1200th photoconductor production, the mass production was stopped, but after that, the spray gun was cleaned and the production was resumed. No photoconductor 48 exceeding the sensitivity distribution threshold was manufactured.
[0194]
【The invention's effect】
According to invention of Claim 1,In the image data obtained by visualizing the electrostatic latent image obtained by uniformly exposing and scanning the surface of the uniformly charged photoconductor, the threshold value is determined from the optical information of the noise data in which pixels having optical information exceeding the threshold value are linearly continuous. By acquiring the optical information of all pixels after subtraction as the sensitivity of the photoconductor, it causes troublesome work or damage to the photoconductor by directly measuring the sensitivity of the photoconductor by film thickness measurement, potential measurement, etc. It is possible to easily measure the sensitivity distribution of the photosensitive member over the entire visualized region. Furthermore, the threshold value suitable for the image data is set by obtaining an average value obtained by averaging the optical information of a plurality of pixels including any target pixel in the image data along the continuous direction of the noise data as a threshold value. By subtracting this threshold value from the optical information of all the pixels, it is possible to suppress the generation of a difference between the noise data and the other image data by performing noise removal.
According to invention of Claim 2,Practically, the sensitivity of a photoconductor intended for use in a high-resolution image forming apparatus can be determined with high density.
According to invention of Claim 3,Even when there are a plurality of continuous directions of noise data, the image data is obtained by obtaining an average value obtained by averaging optical information of a plurality of pixels including arbitrary target pixels in the image data along each continuous direction as a threshold value. In addition to setting a threshold suitable for, and subtracting this threshold from the optical information of all pixels, it is possible to suppress the generation of a difference between noise data and other image data by performing noise removal. Can do.
According to invention of Claim 4,The effect of the invention can be obtained even with a photosensitive member having a photosensitive layer formed by a method in which unevenness in film thickness that causes uneven sensitivity of the photosensitive member is likely to occur.
According to invention of Claim 5,The effect of the invention can be obtained even with a photoconductor having a photosensitive layer formed on the outermost layer by a method in which film thickness unevenness that causes sensitivity nonuniformity of the photoconductor is likely to occur.
According to the invention described in claim 6, since it is possible to accurately determine whether or not the sensitivity difference is outside the specified range, if the sensitivity difference is outside the specified range, the manufacturing method is changed. By taking this measure, a large number of photoconductors having a sensitivity difference outside the specified range will not be produced.
According to the seventh aspect of the invention, the image data is acquired from the toner image formed on the recording medium, so that there is a structural restriction such as providing a mechanism for acquiring the image data around the photoconductor. Therefore, the sensitivity unevenness of the photoconductor can be easily determined.
According to the eighth aspect of the present invention, image data can be acquired from the toner image formed on the photosensitive member, and compared with the case where the image data is acquired from the toner image formed on the recording medium. Since the process is not included, it is possible to acquire image data that is not affected by noise generated in the processes after the transfer process.
According to the ninth aspect of the present invention, since the distribution state of the film thickness of the photosensitive layer in the entire visualization area of the photoconductor can be obtained from the sensitivity of the photoconductor, the film thickness is measured using a film thickness meter or the like. The direct measurement does not damage the photosensitive layer.
According to the invention of claim 10, in the image data obtained by visualizing the electrostatic latent image obtained by uniformly exposing and scanning the surface of the uniformly charged photoconductor, pixels having optical information exceeding the threshold value are linearly formed. By acquiring the optical information of all pixels after subtracting the threshold from the optical information of continuous noise data as the sensitivity of the photoconductor, it is complicated to directly measure the photoconductor sensitivity by film thickness measurement, potential measurement, etc. The sensitivity distribution of the photoconductor over the entire visualized region can be easily measured without causing work or damage to the photoconductor. Furthermore, the threshold value suitable for the image data is set by acquiring an average value obtained by averaging the optical information of a plurality of pixels including any target pixel in the image data along the continuous direction of the noise data as a threshold value. By subtracting this threshold value from the optical information of all pixels, it is possible to suppress the occurrence of a difference between noise data and other image data by performing noise removal.
According to the invention of the eleventh aspect, the sensitivity of the photosensitive member intended for use in the high-resolution image forming apparatus can be determined with high density in practice.
According to the invention of claim 12, even when there are a plurality of continuous directions of noise data, an average value obtained by averaging optical information of a plurality of pixels including any target pixel in the image data along each continuous direction Is set as a threshold value, and a threshold value suitable for the image data is set, and by subtracting the threshold value from the optical information of all pixels, noise is removed to obtain a difference between the noise data and the other image data. It is possible to suppress the occurrence of disparity.
According to the thirteenth aspect of the present invention, the effect of the invention can be obtained even with a photosensitive member having a photosensitive layer formed by a method in which unevenness of film thickness that causes sensitivity unevenness of the photosensitive member is likely to occur.
According to the fourteenth aspect of the present invention, the effect of the invention can be obtained even with a photosensitive member having a photosensitive layer formed on the outermost layer as a method in which film thickness unevenness that causes sensitivity unevenness of the photosensitive member is likely to occur. Can do.
According to the fifteenth aspect of the invention, it is possible to accurately determine whether or not the sensitivity difference is outside the specified range. Therefore, when the sensitivity difference is outside the specified range, the manufacturing method is changed. By taking this measure, a large number of photoconductors having a sensitivity difference outside the specified range will not be produced.
According to the sixteenth aspect of the present invention, there is a structural restriction such as providing a mechanism for acquiring image data around the photosensitive member by acquiring the image data from the toner image formed on the recording medium. Therefore, the sensitivity unevenness of the photoconductor can be easily determined.
According to the seventeenth aspect of the present invention, image data can be acquired from the toner image formed on the photosensitive member, and compared with the case where the image data is acquired from the toner image formed on the recording medium. Since the process is not included, it is possible to acquire image data that is not affected by noise generated in the processes after the transfer process.
According to the invention described in claim 18, since the distribution state of the film thickness of the photosensitive layer in the entire visualization area of the photoconductor can be obtained from the sensitivity of the photoconductor, the film thickness is measured using a film thickness meter or the like. The direct measurement does not damage the photosensitive layer.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of a photoconductor sensitivity distribution measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a longitudinal side view schematically showing an image forming apparatus for forming an image on a sheet using a photoconductor as a surface sensitivity measurement target.
FIG. 3 is an explanatory diagram showing noise generated in an image formed using an electrophotographic method.
FIG. 4 is a block diagram illustrating a configuration of a Y-direction noise removing unit.
FIG. 5 is a flowchart schematically illustrating noise removal processing executed by a Y-direction noise removal unit.
FIG. 6 is an explanatory diagram showing pixels that average optical information.
FIG. 7 is an explanatory diagram showing noise generated in an image formed by using an electrophotographic method.
FIG. 8 is a block diagram illustrating a configuration of an X-direction noise removing unit.
FIG. 9 is a flowchart schematically illustrating noise removal processing executed by an X direction noise removal unit;
FIG. 10 is a block diagram illustrating a configuration example of a photoconductor sensitivity distribution measuring apparatus according to a second embodiment of the present invention.
FIG. 11 is an explanatory diagram illustrating an image after noise removal processing in the embodiment.
[Explanation of symbols]
1 Photosensitive sensitivity distribution measuring device
2 Data acquisition means
48 photoconductor

Claims (18)

A photoconductor sensitivity distribution measuring apparatus comprising at least data acquisition means (A), noise removal means (B), and sensitivity acquisition means (C),
The data acquisition means (A)
Means for acquiring image data including optical information of each pixel constituting an image obtained by visualizing an electrostatic latent image formed by uniformly exposing and scanning a uniformly charged photoreceptor surface;
Noise that continues in a straight line having directionality in the sub-scanning direction y and / or the main-scanning direction x , which occurs without causing the pixels having the optical information in the acquired image data to be caused by uneven sensitivity of the photoconductor In the case of having data, in order to remove the noise data, noise direction determination means for determining the continuous direction of the noise data;
When the continuous direction of the noise data determined by the noise direction determination unit is the sub-scanning direction y, an arbitrary pixel of interest P (x, y) in the image data is included along the sub-scanning direction y An average value acquisition unit that averages optical information of a plurality of pixels to acquire an average value Pave (x, y) ,
The noise removing means (B)
Based on the acquired image data, the average value of the optical information of all pixels is Pave,
Using the average value Pave (x, y) acquired by the average value acquisition means from the optical information of each pixel of interest P (x, y) as a threshold value, the following expression P ′ (x, y) = P (x, y ) -Pave (x, y) + Pave
The noise removing means (B) for subtracting the threshold value from the optical information of noise data in which pixels having optical information are linearly continuous,
The sensitivity acquisition means (C)
A photosensitive member sensitivity distribution measuring apparatus, wherein the noise removing unit (B) is a sensitivity acquisition unit (C) that acquires optical information of all pixels after the threshold is subtracted as the sensitivity of the photosensitive member. 2. The photosensitive member sensitivity distribution measuring apparatus according to claim 1 , wherein the pixel of interest P (x, y) is set at one point for each unit obtained by dividing the visualized region on the surface of the photosensitive member by a unit of 100 mm < ² > or less. And direction number determining means for continuing direction of the noise data to which the noise direction determination means determines it is determined whether a plurality of,
When the number-of-directions determination unit determines that there are a plurality of continuous directions of the noise data, an arbitrary target pixel in the image data is selected along one continuous direction of the noise data determined by the noise direction determination unit. A first average value acquisition means for averaging the optical information of a plurality of pixels including to acquire a first average value;
Subtracting means for subtracting the first average value acquired by the first average value acquisition means from the optical information of each target pixel, with all the pixels in the image data as the target pixel,
The optical after the subtraction means subtracts the first average value from a plurality of pixels including any target pixel in the image data along another continuous direction of the noise data determined by the noise direction determination means A second average value acquisition means for averaging information and acquiring a second average value;
The noise removing unit (B) sets the second average value acquired by the second average value acquiring unit from the optical information of each pixel of interest as all the pixels in the image data as the pixel of interest. 3. The photosensitive member sensitivity distribution measuring apparatus according to claim 1, wherein the photosensitive member sensitivity distribution is subtracted as a threshold value.   4. The photosensitive member sensitivity distribution measuring apparatus according to claim 1, wherein the photosensitive member has a photosensitive layer in which a plurality of layers, at least one layer of which is formed using a spray coating method, are laminated on a substrate surface.   4. The photosensitive member sensitivity distribution measuring apparatus according to claim 1, wherein the photosensitive member has a photosensitive layer that is laminated on a surface of a substrate and has an outermost layer formed by a spray coating method. Based on the sensitivity of the photoconductor acquired by the sensitivity acquisition unit (C), a distribution state determination unit that determines whether or not the sensitivity difference in the entire visualization region of the photoconductor is outside a specified range is provided. The photoconductor sensitivity distribution measuring apparatus according to claim 1, 2, 3, 4, or 5. The said data acquisition means (A) acquires the said image data of the image which visualized the electrostatic latent image by transferring the toner adhering to the said photoreceptor surface to a recording medium. The photoconductor sensitivity distribution measuring apparatus according to 4, 5, or 6. The said data acquisition means (A) acquires the said image data of the image which visualized the electrostatic latent image by making toner adhere to the said photoreceptor surface. The photosensitive member sensitivity distribution measuring apparatus as described. A film thickness storage device that stores the sensitivity of the photosensitive member and the film thickness of the photosensitive layer in association with each other in a storage area;
A film thickness distribution for acquiring the distribution state of the film thickness of the photosensitive layer in the entire visualization area of the photoconductor based on the sensitivity of the photoconductor acquired by the sensitivity acquisition means (C) with reference to the storage area. Acquisition means;
9. A photoconductor sensitivity measuring apparatus according to claim 1, 2, 3, 4, 5, 6, 7 or 8. A photoconductor sensitivity distribution measuring method comprising at least a data acquisition step (D), a noise removal step (E), and a sensitivity acquisition step (F),
The data acquisition step (D)
Obtaining image data including optical information of each pixel constituting an image obtained by developing an electrostatic latent image formed by uniformly exposing and scanning a uniformly charged photoreceptor surface;
Noise that continues in a straight line having directionality in the sub-scanning direction y and / or the main-scanning direction x , which occurs without causing the pixels having the optical information in the acquired image data to be caused by uneven sensitivity of the photoconductor A noise direction determining step for determining a continuous direction of the noise data in order to remove the noise data in the case of having data;
When the continuous direction of the noise data determined by the noise direction determination step is the sub-scanning direction y, the image data includes an arbitrary pixel of interest P (x, y) along the sub-scanning direction y. An average value acquisition step of averaging optical information of a plurality of pixels to acquire an average value Pave (x, y) ,
The noise removing step (E)
Based on the acquired image data, the average value of the optical information of all pixels is Pave,
Using the average value Pave (x, y) acquired by the average value acquisition means from the optical information of each pixel of interest P (x, y) as a threshold value, the following expression P ′ (x, y) = P (x, y ) -Pave (x, y) + Pave
A noise removing step (E) in which the threshold value is subtracted from optical information of noise data in which pixels having optical information are linearly continuous,
The sensitivity acquisition step (F)
The photosensitive member sensitivity distribution measuring method, wherein the noise removing step (E) is a sensitivity acquisition step (F) in which optical information of all pixels after the threshold is subtracted is acquired as the sensitivity of the photosensitive member. 11. The photosensitive member sensitivity distribution measuring method according to claim 10, wherein the target pixel P (x, y) is set at one point for each unit obtained by dividing the visualized region of the surface of the photosensitive member by a unit of 100 mm ² or less. The direction number determination step of continuing direction of the noise data to which the noise direction determination step determines that determines whether a plurality of,
When it is determined that there are a plurality of continuous directions of the noise data, the optical information of a plurality of pixels including an arbitrary pixel of interest in the image data is averaged along one continuous direction of the determined noise data. A first average value acquisition step of acquiring one average value;
Subtracting the first average value from the optical information of each pixel of interest, with all pixels in the image data as the pixel of interest,
The second average value is obtained by averaging the optical information after subtracting the first average value of a plurality of pixels including any target pixel in the image data along another continuous direction of the determined noise data. A second average value acquisition step of acquiring
Have
The noise removal step (E) uses all the pixels in the image data as the target pixel, and subtracts the second average value from the optical information of each target pixel as the threshold value. Photoconductor sensitivity distribution measurement method.   The photoconductor sensitivity distribution measuring method according to claim 10, 11 or 12, wherein the photoconductor has a photoconductive layer in which at least one layer is formed by spray coating and has a plurality of layers laminated on a substrate surface.   The photoconductor sensitivity distribution measuring method according to claim 10, wherein the photoconductor layer, the outermost layer of which is formed using a spray coating method, is intended for the photoconductor having the substrate surface laminated thereon. 13. A distribution state determination step for determining whether or not the sensitivity difference in the entire visualization region of the photoconductor is outside a specified range based on the acquired sensitivity of the photoconductor. 15. A method for measuring the sensitivity distribution of a photoreceptor according to 13 or 14 .   In the step of acquiring the image data in the data acquisition step (D), the electrostatic latent image formed by uniformly exposing and scanning the surface of the uniformly charged photosensitive member is visualized. An electrostatic latent image formed on the surface of the photoconductor is visualized by the imaging device using a visualization device that attaches toner to the surface of the photoconductor and a transfer device that transfers the toner attached to the surface of the photoconductor to a recording medium. 16. The photosensitive member sensitivity distribution measuring method according to claim 10, wherein the electrostatic latent image is visualized by transferring the adhered toner onto the recording medium by the transfer device.   In the step of acquiring the image data in the data acquisition step (D), the electrostatic latent image formed by uniformly exposing and scanning the surface of the uniformly charged photosensitive member is visualized. The image forming apparatus that causes a toner to adhere to the surface of the photosensitive member and visualizes the electrostatic latent image by attaching the toner to the electrostatic latent image on the surface of the photosensitive member by the image forming device. The photoreceptor sensitivity distribution measuring method according to 10, 11, 12, 13, 14 or 15.   With reference to a storage area in which the sensitivity of the photosensitive member and the film thickness of the photosensitive layer are stored in association with each other, the film thickness of the photosensitive layer in the entire visualization region of the photosensitive member based on the sensitivity of the photosensitive member 18. The method for measuring sensitivity of a photosensitive member according to claim 10, further comprising a film thickness distribution acquisition step of acquiring a distribution state.

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