Patent ID: 7327265

Claim:
A RF tag reader/writer, comprising: a conveyance plate including a conveyance surface for conveying a paper containing a RF tag in a paper conveying direction; an antenna having a front surface facing toward the paper conveyed by the conveyance plate, and a back surface facing away from the paper conveyed by the conveyance plate, at least one radiation element being positioned on the front surface such that the RF tag provided in the paper conveyed on the conveyance surface passes over the radiation element, and all of the back surface being grounded; a communication section for transmitting and receiving radio waves to and from the RF tag through the antenna so as to execute data communication with the RF tag; and a radio wave passage provided in the conveyance plate at a position corresponding to the antenna such that the radio waves between the antenna and the RF tag pass through the radio wave passage; wherein a width along the paper conveying direction of an area over which the at least one radiation element is provided on the front surface of the antenna is not larger than a width of the radio wave passage along the paper conveying direction, and wherein a width of the antenna along the paper conveying direction is larger than the width of the radio wave passage along the paper conveying direction.