Image forming apparatus



【課題】二成分現像剤を使用する現像器内の異常を早期に検知し、異常に対し最善に対処して常に安定した画像形成を行う画像形成装置を提供する。 【解決手段】所定の印字休止時に強制的に一定量(1.5g)のトナー補給動作を行う。トナー補給前のトナー濃度センサ48のセンサ出力a、平均値の予測値b(2.63V)、一定時間(現像槽一周分)内のセンサ出力の最大値c、最小値d、算出された平均値eとして以下の状態を検知して括弧内のように対処する。c−d>0.8なら攪拌不良(一定時間攪拌)、c−d≦0.8且つ|b−e|<0.2なら正常、c−d≦0.8且つ|b−e|<0.2且つ|b−e|>0ならキャリア減少(補給閾値を修正)、c−d≦0.8且つ|b−e|<0.2且つb−e≦0且つ|a−e|≧0.3ならトナー過補給(通常補給可能までドットカウンタでトナー消費量を計算)、|a−e|<0.3ならトナー供給不足(オペレータコール)。 【選択図】図7
PROBLEM TO BE SOLVED: To provide an image forming apparatus always stably forming an image by detecting abnormality in a developing unit using a two-component developer in an early stage and coping with the abnormality to the best.SOLUTION: A toner of a constant amount (1.5 g) is forcibly supplied during a predetermined printing pause. The sensor output a of a toner concentration sensor 48 before the toner is supplied, the predicted value b (2.63 V) of the average value, the maximum value c and minimum value d of the sensor output in a fixed time (one round of a developing tank), and a calculated average value e are used to detect the following states and cope with the problems, that is, execute the contents in parentheses: when c-d>0.8 is obtained, stirring failures occur (stirring for the fixed time), when c-d≤0.8 and |b-e|<0.2 are obtained, it is normal, when c-d≤0.8, |b-e|<0.2, and |b-e|>0 are obtained, the number of carriers is decreased (a supply threshold is corrected), when c-d≤0.8, |b-e|<0.2, b-e≤0, and |a-e|≥0.3 are obtained, the toner is over-supplied (toner consumption is calculated by a dot counter, until normal supply becomes possible), and when |a-e|<0.3 is obtained, the supply of the toner is insufficient (operator call).




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Cited By (1)

    Publication numberPublication dateAssigneeTitle
    US-9709919-B2July 18, 2017Ricoh Company, Ltd.Developing device, image forming apparatus, and process cartridge