Patent ID: 8831502

Claim:
An image forming apparatus, comprising: a first image reading unit at an upper portion of a main body of the image forming apparatus; and a second image reading unit at a lateral portion of the main body of the image forming apparatus; wherein the first image reading unit includes a first operating part and a first sheet position sensor, wherein the second image reading unit includes a second operating part and a second sheet position sensor, wherein when the first sheet position sensor detects a first original manuscript sheet, input operation to the second operating part is invalidated, the second image reading unit is disabled, and the second operating part displays a message indicating that the second image reading unit is disabled, wherein when the second sheet position sensor detects a second original manuscript sheet, input operation to the first operating part is invalidated, the first image reading unit is disabled, and the first operating part displays a message indicating that the first image reading unit is disabled, wherein the second image reading unit further includes a unit configured to establish a first state for transporting the second original manuscript sheet for image reading, and a second state for transporting a transfer sheet that is manually fed for image formation by the main body of the image forming apparatus, wherein the second image reading unit has an automatic transport function for transporting the second original manuscript sheet for the image reading, and includes a first tray unit for placing the second original manuscript sheet prior to the image reading and a second tray unit into which the second original manuscript sheet is ejected after the image reading, wherein the first and second tray units are configured to be set in a stored state, in which the first and second tray units are closed toward a surface of the main body of the image forming apparatus on which the second image reading unit is mounted, or in an image-reading state, in which the first and second tray units are opened away from the mounted surface, and wherein the first tray unit is configured to be set in a third state, in which a position of the first tray unit differs from the position of the first tray unit in either the stored state or the image-reading state, for transporting the transfer sheet that is manually fed.