Image reader having document detector for detecting presence or absence of document sheet to determine reading range

Abstract

In an image reader, a controller control, during a period from a timing when a detector detects an open state of a cover to a timing when the detector detects a closed state of the cover, a document detector to detect whether a document sheet is present or absent every time a prescribed time period is elapsed, and stores in a memory each set of first data indicating absence or presence of the document sheet. The controller determines a first size of the document sheet in a main scanning direction. The controller determines a second size of the document sheet in a sub scanning direction on the basis of the sets of first data. The controller determines a reading range on the basis of the first and second sizes. The reading section reads the determined reading range on the line-to-line basis to obtain an image of the document sheet.