The present application relates to an image processing apparatus and a method for matching and combining two documents with at least some overlap area. The ink channel has a valve accommodation room and a valve opening formed in a wall surface located at one end of the valve accommodation room. The data message communicated between the units are defined into multiple message classes. The machine operates to cause an authorized user to be credited for deposited items such as notes and checks. The battery cover mechanism is convenience to operate, and avoids the interfering signals efficiently.