PAPER FEEDER AND IMAGE FORMING APPARATUS INCLUDING THE SAME

PROBLEM TO BE SOLVED: To acquire the number of remaining recording sheets with high accuracy even if reused recording papers are loaded and accommodated to be extracted for use.SOLUTION: A paper feeder counts the number of recording sheets P extracted by a pickup rocker 23, calculates the difference between a first height h1 and a second height h2 detected by a height sensor 29 when the number of the extracted recording sheets reaches a first number N1 or when the number reaches a second number N2 larger than the first number N1, calculates a thickness t of the recording sheets on the basis of the difference between the heights and the difference between the first number N1 and the second number N2, and calculates the number Na of remaining recording sheets on the basis of the thickness t of the recording sheets and the height N2.SELECTED DRAWING: Figure 4 【課題】再使用の記録紙を積載して収容し、その記録紙を引出して使用する状態においても、残り枚数を高精度で求めることを可能にする。【解決手段】ピックアップローラー２３による記録紙Ｐの引出し枚数を計数し、引出し枚数が第１枚数Ｎ１及び第１枚数Ｎ１よりも多い第２枚数Ｎ２に達したそれぞれのときに高さ位置センサー２９により検出された第１高さ位置ｈ１及び第２高さ位置ｈ２の差を求め、この高さ位置の差及び第１枚数Ｎ１と第２枚数Ｎ２との枚数の差に基づき記録紙の厚みｔを求め、記録紙の厚みｔ及び第２高さＮ２に基づき記録紙の残り枚数Ｎａを求める。【選択図】図４