EDGE DETECTION DEVICE, IMAGE FORMING APPARATUS, EDGE DETECTION METHOD, AND PROGRAM

PROBLEM TO BE SOLVED: To more accurately detect a sheet edge of a recording medium (transfer paper) to be conveyed, the sheet edge to be a reference position to write an image.SOLUTION: An edge detection device comprises: a signal acquisition part 101 that acquires electric signals from a plurality of rows of pixels obtained by projecting light beams from a plurality of light sources that are arranged in a main scanning direction orthogonal to a conveyance direction of a recording medium to be conveyed; a recording medium presence determination part 102 that determines the presence of a recording medium on the basis of an electric signal at the head of the plurality of rows of pixels; an inversion part 103 that, when the electric signals of the plurality of rows of pixels are changed at a predetermined number of pixels, inverts the polarity of the electric signals and outputs resulting electric signals; and a detection part 104 that detects an edge to be a reference position to write an image in the recording medium on the basis of the inversion part 103.SELECTED DRAWING: Figure 6 【課題】搬送される記録媒体（転写紙）の画像書込み基準となる用紙エッジをより正確に検出すること。【解決手段】搬送される記録媒体の搬送方向と直交する主走査方向に配列した複数の光源の光を投射して得られる複数の画素列の電気信号を取得する信号取得部１０１と、取得した複数の画素列の先頭部分の電気信号を基に記録媒体の有無を判断する記録媒体有無判断部１０２と、複数の画素列の電気信号が所定数の画素数で変化した場合に当該電気信号の極性を反転して出力する反転部１０３と、反転部１０３に基づいて上記記録媒体の画像書込み位置の基準となるエッジを検出する検出部１０４と、を備える。【選択図】図６