A document reading device includes a document transport and, for reading a document image, an optical reader having a movable exposure which stops at a predetermined reading position and emits light onto the document. A guide member guides the document to the reading position to form a predetermined inclination angle with respect to a flat-plate face of a support, which supports the document being transported when it passes over the reading position. A transport path is formed with the support so that the document passing over the reading position is transported along the flat-plate face. A detection member detects a leading end position of the guide member, the predetermined reading position being set to within a predetermined distance in a transport direction from the leading end of the guide member, which is known beforehand to be stain-free.

The present invention is to provide an image reader including a transparent substrate, which can be used effectively for an extended lifetime. The image reader comprises a transparent substrate and a stationary image pickup opposed to the transparent substrate for reading an image of an original document while the document is being transported between the transparent substrate and the stationary image pickup. The transparent substrate can be turned around and/or upside down relative to the image pickup in order to use the transparent substrate for an extended its service time. Also, the transparent substrate includes at least one first indicator showing an arrangement order how the transparent substrate has been turned around relative to the image pickup.

In image reading apparatus capable of performing a read-while-feed operation in which an original is read while being fed by an image sensor placed at a fixed position, presence/absence of dust and/or dirt on a platen is detected, and, in a case where dust and/or dirt are detected at all of a plurality of predetermined positions by said detector, the read-while-feed operation is inhibited and the presence of dust and/or dirt is notified to a user. When, removal of dust and/or dirt on the platen is detected in a state that the read-while-feed operation is inhibited, the read-while-feed operation is allowed.

The object of this invention is to provide an image reading apparatus capable of greatly reducing generation of a black streak image caused by dust, dirt, or the like at a flow scanning position on a document glass table in flow scanning of reading a document image while moving the document sheet at a predetermined speed. To achieve this object, the CPU of the image reading apparatus performs dust detection processing of detecting dust on the document glass table by a dust detection circuit during a document nonreading period. The CPU executes dust correction processing based on the dust detection result during continuous document reading. During an interval between the end of a series of image reading JOBs and the next image reading JOB, the CPU performs dust avoidance processing of changing the flow scanning position to a position free from any dust on the document glass table. If dust is difficult to avoid, the CPU inhibits flow scanning and executes control of switching flow scanning to optical scanning document reading.