IMAGE READING DEVICE AND IMAGE FORMING APPARATUS

摘要

An image reading device includes: an image reading section configured to read an image of an original document; a document size detecting section configured to use image data acquired by the image reading section with an original cover open to detect a size of the original document in a main scanning direction; and a control section configured to allow the document size detecting section to perform a detection of the size of the original document by lighting a light source of the image reading section at an initial light intensity, subsequently allow the document size detecting section to perform another detection of the size of the original document by lighting the light source at a reduced light intensity, and set, when the same size has been detected in the two detections of the size of the original document, the reduced intensity as a document size detection light intensity.

主权项

1. An image reading device comprising:
an original glass plate for use with an original document placed on a top surface thereof; an original cover pivotally mounted at one edge thereof and capable of surface contact with the original glass plate; an image reading section configured to read the original document to acquire image data of the original document and including a light source capable of irradiating the original document with light from under the original glass plate, an optical system configured to form an optical image of reflected light from the original document irradiated by the light from the light source, and an image sensor configured to convert the optical image formed by the optical system into an electrical signal; a document size detecting section configured to use the image data acquired by the image reading section with the original cover open to detect a size of the original document in a main scanning direction of the image reading section; and a control section configured to allow the document size detecting section to perform a detection of the size of the original document by lighting the light source at an initial light intensity, subsequently allow the document size detecting section to perform another detection of the size of the original document by lighting the light source at a light intensity reduced by a predetermined value from the initial light intensity, and set, when the same size has been detected in the two detections of the size of the original document, the reduced intensity as a document size detection light intensity at which the light source is to be lit in detecting the size of an original document next time.